Tesi sul tema "Conservation biology"

Bees provide the essential ecosystem service of pollination, contributing ca. 35% of global food production, but declines in their populations have been reported worldwide. Currently, one third of the Irish bee fauna is listed as threatened. This thesis aimed to provide essential information on the conservation genetics and ecology of Irish bees. A comparis?n of published data on microsatellite markers revealed that haplodiploidy alone had no influence on genetic div~rsity whereas eusociality probably reduced it. Globally, >90% of bee species are solitary, rather than social. Ireland has over 75% of the Atlantic zone populations of Colletes floralis, an endangered solitary species. Using novel microsatellite markers,' C. floralis populations exhibited considerable genetic and geographic structuring, with little evidence of inbreeding. The taxonomy of Bombus sensu stricto is complicated by intraspecific variation. ' Phylogenetic analyses of CO1 sequences confirmed a barcoding gap between three cryptic species of the B. lucorum complex. A novel PCR-RFLP method differentiated and described the Irish distribution of them. Furthermore, an independent dataset of Irish bumblebee species tested alternative hypotheses regarding bumblebee declines. Despite parallel declines in Britain and Ireland, there was no relationship between declines and species' European ranges or food-plant specialisatiOIi.. The majority of Ireland's landmass is involved in agriculture, necessitating the accurate description of bee communities within the remaining areas .of conserved habitat. A survey of protected sites found that calcareous grasslands and dry heaths had the highest diversity 'and density of bees, respectively. Despite considerable niche overlap, communities were not highly competitively structured. Up to 72% of the variation in species-abundance distributions could be explained by characters relating to nesting habitat. Only upon integrating population genetics, intrinsic site characters and extrinsic, landscape scale, factors will habitat management translate into sustainable conservation management of Irish bees and the pollination services they provide.

Doutoramento em Biologia
Existe um consenso generalizado de que o estudo da biologia reprodutiva de espécies endémicas, raras ou ameaçadas é essencial para compreender o seu estado actual e no desenvolvimento de estratégias adequadas de conservação in situ e ex situ. Polygala vayredae Costa (Polygalaceae) é uma espécie endémica da cadeia pré-Pirenaica oriental classificada como vulnerável de acordo com as categorias da IUCN. Os objectivos da presente Tese de Doutoramento consistiram em estudar a biologia reprodutiva de P. vayredae, avaliando de que forma pode afectar o ciclo de vida, em fornecer informação de base para futuros programas de conservação e em explorar em maior profundidade as interacções planta-animal e os processos de evolução de determinados traços florais. Para alcançar estes objectivos foram investigados os seguintes tópicos: biologia floral e sistema de reprodução (Capítulo 2), mecanismo de apresentação secundária de pólen (ASP, Capítulo3), ecologia da polinização (Capítulo 4) e mecanismos de dispersão (Capítulo 5). Os resultados revelaram que (1) P. vayredae depende estritamente de vectores de polinização para produzir sementes, (2) as suas características florais (corola fechada, accionada por comportamentos específicos do insecto) limitam o conjunto de polinizadores eficientes, (3) a sua longevidade floral favorece a transferência de pólen mas apresenta também custos reprodutivos sobre o êxito feminino, (4) a ASP acarreta custos reprodutivos sobre o êxito das componentes masculina e feminina, (5) as flores de P. vayredae são visitadas por um diversificado conjunto de insectos, dos quais apenas quatro espécies se comportam como polinizadores eficientes, (6) os polinizadores eficientes são, frequentemente, escassos e variáveis ao longo do tempo e do espaço, (7) os visitantes ineficientes exercem um efeito negativo sobre o comportamentos dos polinizadores eficientes e consequentemente sobre o êxito masculino (reduzindo o fluxo de pólen) e feminino (reduzindo a produção de frutos e sementes), (8) a dispersão dos frutos alados a longas distâncias encontra-se largamente reduzida, e finalmente, (9) a dispersão é maioritariamente efectuada por formigas que dispersam as sementes a distancias reduzidas, com o conjunto de espécies variando grandemente entre populações e anos. Perante estas observações podemos concluir que P. vayredae apresenta os seguintes problemas reprodutivos: limitação de pólen/polinizadores e curtas distâncias de dispersão. Os programas futuros de conservação que considerem estes pontos, conservando a fauna da área e protegendo as interacções planta-animal, promoverão a manutenção das populações e, consequentemente, a conservação desta espécie.
There is a consensus that studies on the reproductive biology of endangered, rare or threatened species are useful for understanding their current status and for evaluating in situ and ex situ management strategies. Polygala vayredae Costa (Polygalaceae) is a narrow endemic species from oriental pre-Pyrenees classified as vulnerable according with the IUCN categories. The aims of this PhD thesis were to study the reproductive biology of P. vayredae, to evaluate the implications of its reproductive features on its life cycle, to provide valuable background information for future management programs and deeply explore plant-animal interactions and the evolution of certain floral traits. To achieve the proposed objectives the following points were investigated: the floral biology and breeding system (Chapter 2), the singular secondary pollen presentation (SPP) mechanism (Chapter 3), the pollination ecology (Chapter 4) and the dispersal mechanisms (Chapter 5). The results revealed that (1) P. vayredae strictly depends on pollen vectors to produce seeds, (2) its floral features (closed corolla and the need to be trigged by specific behaviours of the insects) limit the spectrum of efficient pollinators, (3) its floral longevity favours the opportunity to pollen transfer but also have reproductive costs over female fitness, (4) SPP imposes several reproductive costs over male and female fitness, (5) a large spectrum of floral visitors were observed, but with only four species being efficient pollinators, (6) efficient pollinators were scarce and highly variable both along time and space, (7) inefficient visitors add a negative effect on the behaviour of efficient pollinators and on male (reducing pollen flow) and female components (reducing fruit set and seed ovule ratios), (8) long dispersal of the alate fruits is largely reduced, and finally, (9) dispersal is mainly performed by ants who are able to disperse seeds for short distances, with the spectrum of ant species being spatially and temporally variable. The general conclusions on the status of P. vayredae indicate that this species bears the following reproductive problems: pollen/pollinator limitation and short distance dispersal of the diaspores. Future management programs that account with this issues conserving the fauna of the area and protecting plant-animal interactions will facilitate the maintenance of the populations and thus its conservation.

New Zealand sea lion (Phocarctos hookeri) is a pinniped endemic to New Zealand and is among the rarest of sea lion species. New Zealand sea lions are incidentally caught in the trawl fishery for squid around the Auckland Islands, and a sea lion catch-limit or Fishing Related Mortality Limit (FRML) is used to manage this interaction. Since 2003 such limits have been calculated using an age-structured Bayesian population model. One problem with this approach is that several key demographic parameters have had to be assumed, or are based on very few data. Archaeological and other historical records demonstrate that New Zealand sea lions were substantially more widespread before the arrival of humans to New Zealand than they are today (Chapter 2 published as Childerhouse & Gales 1998). The present population size is clearly reduced, with subsistence and commercial hunting the most likely cause of historical changes in distribution and abundance. Campbell Island, the only significant breeding site outside the Auckland Islands, was thoroughly surveyed for New Zealand sea lions for the first time in 2003. An estimated 385 pups were born there, comprising 13% of the total pup production for the species for 2003 (Chapter 3 published as Childerhouse et al. 2005). This thesis provides the first robust estimates of several demographic parameters for New Zealand sea lions. These data were gained via the capture, tagging and ageing of 865 individual females, which had come ashore to pup between 1999 and 2001. This research was underpinned by the development of a novel and robust ageing technique for live New Zealand sea lions (Chapter 5 published as Childerhouse et al. 2004). Chapters 6, 7 and 8 used analyses of the age structure of these females, and of subsequent resightings of them, and of known-age females between 1998 and 2005, provided the first estimates of individual growth, mean reproductive rate (0.67, SE = 0.01), mean adult survival (0.81, SE = 0.04), and maximum age (28 years) for females. These data show that New Zealand sea lions are among the slowest growing, slowest reproducing, and longest lived sea lion species. Significant differences in the age structure of the two largest breeding colonies highlight flawed assumptions of the current management approach. The application of this new demographic information has the potential to significantly alter the existing management advice relating to the setting of FRMLs and the impact of the squid fishery on the New Zealand sea lion population. Taken alone, these results suggest a dim outlook for an already threatened species. In the context that pup production is in significant decline (e.g. 32% since 1998 Chilvers et al. 2007), the species� foraging environment is thought to be marginal (Costa & Gales 2000), and that resource competition may also be impacting on the population (Chapter 4 published as Childerhouse et al. 2001a), the picture darkens further. Taken as a whole, these data suggest that current management is insufficient to ensure population stasis, let alone meet the Government�s statutory goal of recovery.

The bottlenose dolphins of Fiordland, New Zealand, live at the southern limit of the species' worldwide range. They are exposed to impacts from tourism and habitat modification, particularly in Doubtful Sound, and their conservation requirements are presently unclear. Dolphin abundance was estimated in Doubtful Sound using photo-identification census and capture-recapture techniques (56 individuals; 95% CI: 55-57), detecting a decline of 34-39% over 12 years among adults and sub-adults (>3 years old). The cause of this decline was investigated via demographic modelling in Doubtful Sound and a comparative assessment of population status in Dusky Sound. Capture-recapture modelling of photo-identification data compiled since 1990 yielded a constant adult survival rate marginally lower than prior estimates for wild bottlenose dolphins ([phi]a(1990-2008) = 0.9374; 95% CI: 0.9170-0.9530). Survival of calves (<1 year old) declined to an unsustainable level that is thought to be the lowest recorded for wild bottlenose dolphins ([phi]c(2002-2008) = 0.3750; 95% CI: 0.2080-0.5782) coincident with the opening of a second tailrace tunnel for a hydroelectric power station. Reverse-time capture-recapture modelling detected declines in recruitment (f(1994-2008) = 0.0249; 95% CI: 0.0174-0.0324) and population growth ([lambda](1994-2008) = 0.9650; 95% CI: 0.9554-0.9746) over time consistent with the decline in calf survival (<1 year old) and a separate reduction in juvenile survival (1 to 3 years old) reflecting cumulative impacts. Dolphin abundance was estimated in Dusky Sound using photo-identification census and capture-recapture techniques (102 individuals, 95% CI: 100-104) providing no evidence of interchange with Doubtful Sound. A comparative assessment of health status between Doubtful and Dusky Sounds revealed skin lesioning was more severe in Doubtful Sound, particularly among females, and newborn calves appeared to be smaller and were born over a shorter period: factors that may contribute to the low levels of calf survival in Doubtful Sound. The Fiordland bottlenose dolphins were assessed under IUCN Red List regional criteria. The small size of the population (205 individuals, 95% CI: 192-219) combined with the projected rate of decline in stochastic matrix models (average decline 31.4% over one generation) resulted in a recommended classification of Critically Endangered.

The conservation biology of Euphydryas aurinia was investigated, analysing its metapopulation dynamics, interactions with parasitoids and the efficacy of habitat restoration. Euphydryas aurinia has undergone a widespread national decline in recent years. This decline is quantified at a 10km scale. The distribution in 2020 was predicted for E. aurinia from the 1995-99 distribution, assuming that the current causes and pattern of decline continued. The predicted distribution in 2020 represented a 48% loss in 10km grid square records, with only the core regions surviving. The distribution and persistence of the butterfly was quantified at a regional scale in one, intensively studied area (25km by 25km) in Dorset (England, UK). The metapopulation approach was useful in understanding the occupancy pattern and persistence of E. aurinia within this landscape. The probability of patch occupancy increased with patch connectivity (isolated patches were less likely to be occupied), vegetation height and resource area (patch area multiplied by host plant cover). Such a pattern was consistent with the interpretation that the butterfly persists as a metapopulation. This supported the use of the Incidence Function Model, as a tool to explore the possible fate of E. aurinia in fragmented landscapes in Dorset and in five pairs of independent networks across the species' range in England and Wales. The threshold network area was predicted to be 7 iha, to achieve a 95% probability of persistence for 100 years, for a network within a 4km by 4km area. However, this figure may actually be an underestimate of the area required, if extinction debt is a reality. Parasitoid attack, principally by Cotesia bignellii, appears to have an effect on the population dynamics of E. aurinia and may help to explain the requirement of E. aurinia for large habitat patches. This preliminary work suggests that the parasitoid also has a metapopulation structure and that it is of equal conservation concern. At a local scale the results suggest that the parasitoid and host may have a shifling disiribution, with the butterfly 'escaping' parasitism in some areas. Habitat restoration and re-creation will be necessary in many networks with insufficient habitat area. Experimental investigation into methods of habitat restoration showed that unsuitable but potential habitat may be restored through cutting twice a year in combination with grazing. Habitat re-creation has been shown to be feasible for agriculturally improved sites, but may be more difficult to achieve due to the higher nutrient status and the competitive interaction of other species with the host plant Succisa pratensis.

This study provides the first assessment of demographic and habitat information for pinto abalone (Haliotis kamtschatkana) in San Diego, California, two decades after the closure of all abalone fisheries in southern California. SCUBA surveys conducted from June 2014 to December 2016 indicate that current low densities (0-0.03 individuals/m²) were far below critical thresholds identified for other abalone species (0.15-0.30 abalone/m²) for successful spawning and recruitment. A broad range of sizes were represented (13-146 mm), however, only 95 individuals were found. Some sites showed significant aggregation of adult (> 50 mm) pinto abalone, 30% of adults had a nearest-neighbor within a critical spawning distance of 2 m, and 65% had a neighbor within 5 m, indicating that at least a small proportion of individuals may be capable of reproducing successfully. Pinto abalone showed a significant preference for boulder habitat at a lower relief (< 10 cm) relative to available habitat– a preference that may influence aggregation around habitat features and enhance reproduction. The frequency, timing, and broad spatial distribution of these surveys was not sufficient to measure patterns in recruitment or changes in abundance, particularly over a strong El Niño event that occurred during the study period. There is a critical need for consistent long-term monitoring in southern California to better understand demographic and environmental processes affecting recovery and persistence of populations, particularly at the southern edge of the broad range of pinto abalone.

I studied the in-water anthropogenic impacts on sea turtles, origins of sea turtles on foraging and developmental areas, their migration routes, and described regionally appropriate conservation needs. Sea turtles inhabiting Baja California waters originate on distant beaches in Japan, Hawaii, and southern Mexico. Results from genetic analyses, flipper tagging and satellite telemetry indicate loggerhead turtles (Caretta caretta) feeding along Baja California's coast are born in Japan and make a transpacific developmental migration of more than 20,000 km, encompassing the entire North Pacific Ocean and that East Pacific green turtles (Chelonia mydas) originate on and return to rookeries in Michoacan, and the Islas Revillagigedo, Mexico. Hawksbill turtles (Eretmochelys imbricata), once the target of a lucrative fishery for their shell, are now extremely scarce and only juveniles were encountered. The region's importance to the biology of sea turtles, regionally and Pacific-wide, warrants urgent conservation action. While protected legally, sea turtles are subject to furtive hunting and incidental catch. Coastal development, pollution, and boat collision are secondary threats. Annual consumption of sea turtles in the region is estimated at between 7,800 and 30,000 animals. Sea turtles are eaten regularly in most coastal communities and turtles are considered an irreplaceable traditional food. The decline of sea turtles in these waters has cost us both ecologically and culturally. Sea turtle recovery in Baja California, as all conservation activities, will be a matter of cultural and social evolution. For recovery to occur, strong, community-based incentives and educational programs are needed. In the near term, increased enforcement efforts, monitoring of mortality, and establishment of sea turtle sanctuaries are among the solutions. Without expansion to include community-specific initiatives such efforts may be futile. A long-term, multi-faceted sea turtle "conservation mosaic" program has been launched, consisting of community-based research on life history and population biology, an international education and public outreach campaign, regional sea turtle conservation areas, a monitoring and stranding network, and several policy initiatives that will permanently protect sea turtles and their habitat.

Conservation of phenotypically variable taxa such as the European whitefish (Coregonus lavaretus) can be particularly challenging. In this thesis it is argued that the recent designation of seven native C. lavaretus populations as three endemic species (C. clupeoides, C. stigmaticus and C. pennantii) by Kottelat & Freyhof (2007) are incorrect and cannot be substantiated with the results presented here. However, evidence for important infra-specific variation between populations has been found. Two native Scottish populations of C. lavaretus show considerable variation in morphology, trophic ecology and life history. The variation in these populations warrants protection, one conservation action becoming more commonly utilised in Britain is conservation translocation. It was found that there were significant differences between source and refuge populations in Scotland. The wisdom of using this conservation measure on a phenotypically plastic organism is discussed. Nevertheless the establishment of further refuge populations are considered to be a viable conservation action. Sub-structuring within the largest native Scottish population of C. lavaretus was not found. However, evidence of residence within certain basins of Loch Lomond was found through significant differences in muscle stable isotope signatures. Investigation was also made into the trophic ecology of other fish in Loch Lomond. It was found that brown trout (Salmo trutta) in Loch Lomond have a non-typical migration pattern and invasive ruffe (Gymnocephalus cernuus) now form an important part of the trophic ecology of this site. In Britain several whitefish populations have been invaded by ruffe, a species native to Britain, but not to these sites. An experiment is conducted into the protective ability against ruffe predation on C. lavaretus ova of substrates typical on spawning grounds. It was found that pebbles and gravel form the best spawning substrate. The impact this mortality may have on the life history of Loch Lomond C. lavaretus is discussed. Using information gathered in this study, recommendations for the management of Coregonus spp. are summerised. There is the potential for these recommendations to apply to other phenotypically plastic species that vary between sites such as Arctic charr (Salvelinus alpinus) and brown trout.

Oceanic islands contribute significantly to global biodiversity due to the high levels of endemism they exhibit. Many island species have, however, become extinct following the arrival of humans, and many others remain threatened. This thesis focuses on one of these threatened island species; the St. Helena Plover, Charadrius sanctaehelenae. The objectives of my PhD were threefold: to understand the current status of the St. Helena Plover, to investigate aspects of its environment that may threaten its persistence, and to compare conservation options. Observational data were used to understand how variation in the environment influences the plover’s distribution and demography. This information was used to inform a controlled trial investigating the use of nest exclosures as a way to improve productivity. New understanding of the species’ population ecology was brought together to create a stochastic meta-population model. This model was used to understand the influence of demographic and life history parameters on the population growth rate and to compare alternative conservation options. Indicators of the future status of the St. Helena Plover population appear mixed; with numbers predicted to decline slowly, but with a high chance of species persistence over the timeframe simulated, 50 years. Nest predation by introduced species, predominately cats, was predicted to suppress nest survival and bring productivity at some sites below that required for population stability. The use of nest exclosures did not increase nest survival and led to a decrease in adult survival. Habitat characteristics were more important in determining the species distribution than influencing its demography. The plovers appeared to select breeding habitat to maximise the visibility from the nest and the accessibility of invertebrate prey. Simulations suggested that predator control would have a large beneficial effect on the population growth rate and that concurrent habitat improvement would have greater than additive benefits. Targets for conservation management include Deadwood Plain; predator control as this key site was predicted to lead to the largest increase in the overall population growth rate, and Man and Horse; there may be potential at this site to increase adult survival, which was found to be the most influential demographic parameter.

The globally Near-threatened Damara Tern Sterna balaenarum is little known and faces several conservation issues. The aim of this study was to provide a description of the ecology and numbers of the species and discuss conservation management plans that will effectively ensure its survival.

In order to prevent species extinctions, conservation strategies need to incorporate the identification and mitigation of the root causes of population decline with an assessment of vulnerability to genetic and stochastic factors affecting small populations. Species or populations with small ranges, such as those on islands, are particularly vulnerable to extinction, and deficient knowledge of these species often impedes conservation efforts. The Bahama Swallow (Tachycineta cyaneoviridis) is an endangered secondary cavity-nester that only breeds on three islands in the northern Bahamas: Abaco, Grand Bahama, and Andros. I investigated questions related to population size and distribution, genetic diversity and population structure, breeding biology, and ecological interactions of the swallow, with the goal of informing the conservation and management of the species. Using several population survey methods on Abaco, I found that swallow site occupancy and density is higher in southern Abaco, especially near roads and pine snags. Future research should prioritize identifying the causes of variable and low population densities in parts of the swallow's range. I used microsatellite markers and morphometrics to assess differences between populations on Abaco and Andros. We found a lack of genetic differentiation (G'ST = 0.03) between populations, but differences in morphology suggest that gene flow might be low enough to enable traits under selection to diverge. By locating and monitoring nests, I found that swallows rely on woodpecker-excavated cavities in pine snags and utility poles, and that swallows nesting in pine snags had higher fledging success (92%) than those nesting in utility poles (50-62%). Using a cavity nest-web approach, I assessed how swallows interact with cavity-nesting birds and resources on Abaco. Hairy Woodpeckers (Dryobates villosus) primarily excavated pine snags, while West Indian Woodpeckers (Melanerpes superciliaris) excavated utility poles in non-pine habitat. Only swallows and La Sagra's Flycatchers (Myiarchus sagrae) used nest sites in the pine forest. Swallows in non-pine habitat face competition for cavities with American Kestrels (Falco sparverius), and non-native House Sparrows (Passer domesticus) and European Starlings (Sturnus vulgaris). These results highlight the importance of pine forest and the Hairy Woodpecker for the persistence of the swallow.
Doctor of Philosophy
In order to prevent species extinctions, conservation strategies need to identify and resolve the problems that cause species to decline, as well as address issues characteristic of small populations. Species or populations with small ranges, such as those on islands, are particularly vulnerable to extinction, and lack of knowledge of these species often impedes conservation efforts. The Bahama Swallow is an endangered species that only breeds on three "pine islands" in the northern Bahamas. The swallow is a secondary cavity-nester, which means that it nests in a cavity, usually either a natural tree hole or a hole created by another bird species. In this study, I investigated where swallows are found on the islands, the genetics and body sizes of populations, nesting biology, and connections with other species, with the goal of providing information for the conservation and management of the species. On Abaco, I found that there are more swallows in the southern part of the island, especially near roads and the dead standing pine trees (pine snags) used for nesting. Future research should assess why there are fewer birds in other parts of the swallow's range. I tested whether the genetics and body sizes of populations on Abaco and Andros are different from each other. Populations were genetically similar, but may be separated enough to result in body size differences. I located swallow nests on Abaco, and found that swallows rely on cavities made by woodpeckers in pine snags and utility poles. By visiting some nests repeatedly, I found that swallows nesting in pine snags were more successful than those nesting in utility poles. I also assessed how swallows interact with the other bird species that create and use nesting cavities. Hairy Woodpeckers usually create cavities in pine snags, while West Indian Woodpeckers use utility poles outside of the pine forest. Swallows nesting in the pine forest compete with fewer bird species for cavities than swallows nesting in other habitats. These results show that managing the forest to retain pine snags and Hairy Woodpeckers is important for the conservation of the swallow.

Doutoramento em Biologia
O papel ecológico das gorgónias (Octocorallia: Alcyonacea) nos fundos marinhos rochosos é mundialmente reconhecido. Contudo, a informação acerca da ecologia e biologia das espécies de gorgónias nas zonas temperadas do NE Atlântico é manifestamente escassa, especialmente tendo em consideração as actuais perturbações globais, regionais e locais. Nos fundos rochosos da costa algarvia até aos 30 m, verificouse que várias espécies de gorgónias são abundantes e frequentes, nomeadamente Eunicella labiata, Eunicella gazella, Eunicella verrucosa, Leptogorgia lusitanica e Leptogorgia sarmentosa. As populações de gorgónias são co-dominadas por diferentes espécies que apresentaram elevados índices de associação, indicando reduzidos níveis de competição entre elas. Em todo o caso, a estrutura dos povoamentos diferiu com as condições locais. Todas as espécies evidenciaram padrões de distribuição semelhantes ao longo do gradiente de profundidade, i.e. a abundância aumenta significamente com a profundidade após os 15 m. A profundidades mais baixas (até aos 15 m), a distribuição das gorgónias parece ser condicionada por factores abióticos e pela competição com algas. Com efeito, os padrões de distribuição espacial das espécies de gorgónias na costa algarvia são determinados pela interacção de pressões naturais e antropogénicas (ex. pesca). Ainda que as colónias de maior tamanho não tenham sido restritas a áreas menos pescadas, em áreas mais perturbadas pela pesca, a distribuição dos tamanhos das colónias estava maioritariamente desviada para tamanhos mais pequenos. Os efeitos das perturbações naturais nas populações de gorgónias foram evidenciados pela ocorrência de padrões demográficos distintos em áreas vizinhas sujeitas a níveis semelhantes de pressões antropogénicas. Estes estudos demonstraram, ainda, que os efeitos na distribuição de frequências de tamanho das colónias são dependentes das espécies de gorgónias em causa: Eunicella labiata não parece ser afectada; Leptogorgia sarmentosa é tendencialmente afectada por pressões antropogénicas; Eunicella gazella e Leptogorgia lusitanica aparentam ser afectadas, quer por pressões naturais, quer por pressões antropogénicas. Os efeitos verificados nos padrões da distribuição de frequências de tamanho, particularmente a tendência para o desvio destas frequências para tamanhos mais pequenos em áreas sujeitas a perturbações, poderão ter consequências para a biodiversidade dos fundos sublitorais rochosos na costa algarvia. Com efeito, o presente estudo apoia o paradigma geral de que os corais são habitats que suportam comunidades de elevada biodiversidade e abundância. Num dos poucos estudos que examinam a relação entre as gorgónias e as suas comunidades de invertebrados epibentónicos, foi verificado que as gorgónias (Eunicella gazella e Leptogorgia lusitanica) sustentam comunidades ricas (11 phyla, 181 taxa) e abundantes (7284 indivíduos). Estas comunidades são dominadas por anfípodes, mas os poliquetas tiveram um grande contributo para os níveis elevados de biodiversidade. Verificou-se, igualmente, que o tamanho da colónia desempenha um papel fundamental na biodiversidade, na medida em que as colónias de menor tamanho apresentaram um contributo mais baixo, comparativamente às médias e grandes. Ainda que ambas as gorgónias partilhem a maioria das espécies amostradas, 11 e 18 taxa foram exclusivos de Eunicella gazella e Leptogorgia lusitanica, respectivamente (excluindo indivíduos com presenças únicas). No entanto, a maioria destes taxa eram ou pouco abundantes ou pouco frequentes. A excepção foi a presença de planárias (Turbellaria) de coloração branca nas colónias de Eunicella gazella, provavelmente beneficiando do efeito de camuflagem proporcionado pelos ramos com a mesma coloração. Com efeito, a complementaridade entre as comunidades epibentónicas associadas a ambas as gorgónias diminuiu quando usados os dados de presença/ausência, sugerindo que os padrões de biodiversidade são mais afectados pelas alterações na abundância relativa das espécies dominantes do que pela composição faunística. As comunidades de epifauna bentónica associadas a estas gorgónias não só apresentaram valores elevados de ®-diversidade, como de ¯- diversidade, resultantes de padrões intrincados de variabilidade na sua composição e estrutura. Ainda que o conjunto de espécies disponíveis para colonização seja, na generalidade, o mesmo para ambos os locais, cada colónia apresenta uma parte deste conjunto. Na sua totalidade, as colónias de gorgónias poderão funcionar como uma metacomunidade, mas a estrutura das comunidades associadas a cada colónia (ex. número total de espécies e abundância) parecem depender dos atributos da colónia, nomeadamente superfície disponível para colonização (altura, largura e área), complexidade e heterogeneidade (dimensão fractal e lacunaridade, respectivamente) e cobertura epibentónica “colonial” (ex. fauna colonial e algas macroscópicas; CEC). Numa primeira tentativa para quantificar a relação entre as gorgónias e os invertebrados epibentónicos a elas associados (em termos de abundância e riqueza específica), verificou-se que a natureza e a intensidade destas relações dependem da espécie hospedeira e variam para os grupos taxonómicos principais. No entanto, independentemente do grupo taxonómico, a riqueza específica e a abundância estão significativamente correlacionadas com a CEC. Com efeito, a CEC provavelmente devido a um efeito trófico (aumento da disponibilidade alimentar directo ou indirecto), combinado com a superfície disponível para colonização (efeito espécies-área) foram as variáveis mais relacionadas com os padrões de abundância e riqueza específica. Por outro lado, ainda que a complexidade estrutural seja frequentemente indicada como um dos factores responsáveis pela elevada diversidade e abundância das comunidades bentónicas associadas a corais, a dimensão fractal e a lacunaridade apenas foram relevantes nas comunidades associadas a Leptogorgia lusitanica. A validade do paradigma que defende que a complexidade estrutural promove a biodiversidade poderá ser, então, dependente da escala a que se realizam os estudos. No caso das gorgónias, o efeito da complexidade ao nível dos agregados de gorgónias poderá ser muito mais relevante do que ao nível da colónia individual, reforçando a importância da sua conservação como um todo, por forma a preservar a diversidade de espécies hospedeiras, o seu tamanho e estrutura. Actividades antropogénicas como a pesca, podem, ainda, ter efeitos negativos ao nível da reprodução de espécies marinhas. Analogamente ao verificado para os padrões de distribuição espacial das populações de gorgónias na costa algarvia, a informação relativa à sua reprodução é igualmente escassa. Os estudos realizados em populações de Eunicella gazella a 16m de profundidade, demonstraram que o desenvolvimento anual das estruturas reprodutivas é altamente sincronizado entre os sexos. A razão entre sexos na população foi de 1.09 (F:M), encontrando-se perto da paridade. A espermatogénese estende-se por 6 a 8 meses, enquanto que a oogénese é mais demorada, levando mais de um ano para que os oócitos se desenvolvam até estarem maduros. Antes da libertação dos gâmetas, foi observada uma elevada fecundidade nas fêmeas (27.30§13.24 oócitos pólipo−1) e nos machos (49.30§31.14 sacos espermáticos pólipo−1). Estes valores encontram-se entre os mais elevados reportados à data para zonas temperadas. A libertação dos gâmetas (não há evidência de desenvolvimento larvar, nem à superfície da colónia, nem no seu interior) occorre em Setembro/ Outubro, após um período de elevada temperatura da água do mar. As fêmeas emitem oócitos maduros de elevadas dimensões, retendo, todavia, os oócitos imaturos que se desenvolvem apenas na época seguinte. Ainda que o efeito da pesca nas populações de gorgónias da costa do Algarve seja perceptível, às taxas actuais, o mergulho recreativo não aparenta afectar seriamente estas populações. Contudo, sendo uma indústria em expansão e conhecendo-se a preferência de mergulhadores por áreas rochosas naturais ricas em espécies bentónicas, futuramente poderá vir a afectar estes habitats. A monitorização de mergulhadores na costa algarvia mostrou que a sua maioria (88.6 %) apresenta comportamentos que podem impactar o habitat, com uma taxa média de contactos de 0.340§0.028 contactos min−1. Esta taxa foi mais elevada em mergulhadores com moderada experiência e na fase inicial do mergulho (0–10 min). Os contactos com as barbatanas e mãos foram comuns, resultando, maioritariamente, na resuspensão do sedimento, mas geralmente apresentando um impacto reduzido. Todavia, a fauna também foi afectada, quer por danos físicos, quer pela interacção com os mergulhadores, e num cenário de expansão significativa desta actividade, os impactos na fauna local poderão aumentar, com consequências para os ecossistemas de fundos rochosos da costa sul de Portugal. Na sua globalidade, a informação recolhida nos estudos que contemplam esta tese, por ser em grande parte totalmente nova para a região, espera-se que contribua para a gestão da zona costeira do Algarve.
The ecological role of gorgonians (Octocorallia: Alcyonacea) in marine rocky bottoms is worldwide recognized, but the knowledge on the ecology and biology of NE Atlantic temperate species is insufficient, considering current global, regional and local threats. In the rocky bottoms of the Algarve several gorgonians were abundant and frequent down to 30 m, namely Eunicella labiata, Eunicella gazella, Eunicella verrucosa, Leptogorgia lusitanica and Leptogorgia sarmentosa. There is a high association of several gorgonian species that co-dominate assemblages, indicating low levels of competition among species. Nevertheless, gorgonian assemblages differed in structure, depending on local conditions. All species evidenced a similar depth pattern, i.e. abundance significantly increased with depth below 15 m. At shallower waters (up to 15 m), the distribution of gorgonians may be constrained by abiotic factors and competition with algae. Indeed, the spatial patterns of gorgonian populations along the southern coast of Portugal were driven by the interaction of both natural and anthropogenic pressures (namely fishing). Although larger colonies were not restricted to the sites with lower fishing pressure, gorgonian populations sampled in more intensively fished areas generally presented skewed distributions towards small sizes. The effects of natural disturbance events on the structure of gorgonian populations were evidenced by distinct demographic patterns in nearby areas under similar anthropogenic pressure. The present studies also showed that the effect of disturbance on size-frequency distribution of gorgonian populations is species-dependent: Eunicella labiata does not seem to be affected; Leptogorgia sarmentosa is likely affected mainly by anthropogenic pressures; Eunicella gazella and Leptogorgia lusitanica seem to be affected by both kinds of stress. The effects on sizefrequency distributions patterns, namely the trend to skewed distribution towards small sizes under disturbance may have consequences for biodiversity of rocky sublittoral areas of the Algarve coast. Indeed, the present study supports the general paradigm that corals are habitats of enhanced abundance and biodiversity. In one of the few studies examining the relationship between gorgonians and their associated non-colonial epifaunal assemblages, gorgonians (Eunicella gazella and Leptogorgia lusitanica) were found to support rich (11 phyla, 181 taxa) and abundant (7284 individuals) assemblages. The present study supports the general paradigm that corals are habitats of enhanced abundance and biodiversity. In one of the few studies examining the relationship between gorgonians and their associated non-colonial epifaunal assemblages, gorgonians (Eunicella gazella and Leptogorgia lusitanica) were found to support rich (11 phyla, 181 taxa) and abundant (7284 individuals) assemblages. These epifaunal assemblages were dominated by amphipods, but polychaetes had a relevant contribute to diversity. Colony size was found to have a relevant role on biodiversity patterns, with small size colonies contributing the least for overall biodiversity. Although both gorgonians shared most of the species collected, 11 and 18 taxa were exclusively associated with Eunicella gazella and Leptogorgia lusitanica, respectively (without considering singletons). Nevertheless, most of these exclusive taxa were either rare or uncommon. The exception was the presence of white flatworms Turbellaria in Eunicella gazella colonies probably taking advantage of crypsis with the white Eunicella gazella branches. Indeed, complementarity in the epifaunal assemblages associated with the two gorgonian hosts decreased when data was analysed after presence/absence transformation, suggesting that patterns of biodiversity are more affected by changes in the relative abundance of dominant species rather than in faunal composition. Gorgonian epifaunal assemblages not only showed high values of ®-diversity but intricate patterns of variability in their composition and structure leading to high ¯-diversity. Although the total pool of species available in gorgonian colonies appears to be the same in both sites analysed, each colony yields a rather small set of this species pool. All together, the colonies may act as a metacommunity, but the structure of the assemblage in each colony (e.g. total number of species, dominance) apparently depends upon host attributes, namely the surface available for colonization (colony height, width and area), complexity and heterogeneity (fractal dimension and lacunarity respectively) and “colonial” epibiont cover (e.g. colonial fauna and macroscopic algae; CEC). In a first attempt to explicitly quantify the link between gorgonians and the abundance and species richness of associated non-colonial epifaunal invertebrates, the nature and intensity of these relationships were found to be not only host-dependent but varied from one taxonomic group to another. In all faunal groups associated with the two gorgonian hosts analysed, the species richness and abundance were strongly correlated with CEC. In fact, CEC possibly due to a trophic effect (direct or indirect enhancement of food availability) combined with the surface available for colonization (species-area effect) were the strongest predictors of species richness and abundance. On the other hand, although structural complexity is usually indicated as the main driver for the rich and abundant coral-associated assemblages, fractal dimension and lacunarity were only relevant for the assemblages associated with Leptogorgia lusitanica. The validity of the paradigm that structural complexity enhances biodiversity may be scaledependent. In the case of gorgonians, the effect of complexity at the “garden” level may be much more relevant than at the individual colony level reinforcing the need for the conservation of gorgonian aggregation areas as a whole in order to preserve host diversity and size structure. On the other hand, although structural complexity is usually indicated as the main driver for the rich and abundant coral-associated assemblages, fractal dimension and lacunarity were only relevant for the assemblages associated with Leptogorgia lusitanica. The validity of the paradigm that structural complexity enhances biodiversity may be scale-dependent. In the case of gorgonians, the effect of complexity at the “garden” level may be much more relevant than at the individual colony level reinforcing the need for the conservation of gorgonian aggregation areas as a whole in order to preserve host diversity and size structure. Anthropogenic activities like fishing may also have a negative impact on reproduction. Likewise the lack of information on distribution patterns of gorgonian assemblages and their role on local biodiversity patterns, no information was available for the Algarve coast concerning reproductive patterns of main gorgonian species. The annual development of reproductive structures in Eunicella gazella populations (16m depth) was highly synchronized between sexes. The sex ratio of the population was 1.09 (F:M) being close to parity. The spermatogenic cycle extended for six to eight months, but the oogenic cycle was much longer, taking more than one year for mature oocytes to develop. Prior to spawning, high fecundity was observed in females (27.30§13.24 oocytes polyp−1) and males (49.30§31.14 sperm sacs polyp−1). These values are amongst the highest values reported to date in temperate gorgonians. Broadcast spawning of the gametes (no evidence of surface or internal brooding) occurred in September/October after a period of high sea surface temperatures during summer. Females release large sized mature oocytes but retain immature oocytes that develop only in the next season. Although the effect of fishing on gorgonian assemblages in the Algarve coast is apparent, at current rates, scuba diving does not seem to seriously affect gorgonians. However, this is a growing industry and the preference of scuba divers for natural rocky areas with diverse fauna is well known, which put these habitats under threat. The monitoring of scuba divers in the Algarve showed that most of them (88.6 %) have behaviours that can impact the habitat, presenting a mean contact rate of 0.340§0.028 contacts min−1 (§SE). This rate was higher in scuba divers with moderate experience, and in the initial part of the dive (0–10 min). Contacts with fins and hands were common, mainly resulting in sediment re-suspension, but generally presenting low impact. However, fauna was also affected by physical damage and interactions, and under a scenario of significant expansion of this activity, the impacts on local fauna may increase with consequences for the sublittoral rocky ecosystems of the Algarve coast. Overall, the information gathered in this thesis, most of it completely new for the region, is expected to have a major contribution for the management of the Algarve coast.

The giant bullfrog, Pyxicephalus adspersus, is a large, explosive-breeding anuran from southern Africa, which spends most of the year buried in a state of torpor. In South Africa this species is considered to be Near-Threatened by habitat loss and other factors, especially in the densely human populated Gauteng Province. The aim of this thesis was to obtain essential outstanding information about the ecology of P. adspersus to contribute towards improved conservation management of this species. A model was used to predict the geographic range of P. adspersus in southern Africa, and recent land cover data were used to determine the amount of suitable habitat remaining for this species in Gauteng. As a step towards identifying P. adspersus conservation management units, genetic structure and gene flow for populations from 23 localities in Gauteng and seven additional localities in the north-eastern interior of South Africa was quantified using 708 base pairs of the mitochondrial gene cytochrome b. To investigate the unpredictable activity and unknown spatial habitat requirements of P. adspersus, a population’s spawning and non-breeding activity was monitored, and the movements of 70 adult frogs were radio- or spool-tracked during five summers at a site in Diepsloot, Gauteng. Using skeletohronology, the age distribution of breeding P. adspersus at this and two other peri-urban sites near Johannesburg, Gauteng, was examined. Bioclimatic conditions were predicted to be suitable for P. adspersus in the temperate to semi-arid interior, but not the low-lying eastern subtropical and arid western sides of southern Africa. Limited genetic data suggested that P. adspersus was common in the north-eastern interior of South Africa, and that populations in the Free State Province represent an evolutionary significant unit of this species. In central Gauteng, where P. adspersus may have declined by > 90%, populations < 20 km apart exhibited significant genetic differentiation, possibly as a result of genetic drift. At Diepsloot, both annual numbers of spawning events and numbers of spawning males were positively correlated with rainfall, although other meteorological variables also affected the activity of P. adspersus. Radio- or spool-tracked frogs showed high fidelity to their breeding site and burrows, which were situated up to 1 km away from the water. Male P. adspersus probably live 20 years in the wild, but at some peri-urban breeding sites adult life expectancy and body size may be declining. The geographic range of P. adspersus was predicted to be slightly smaller than that reported by other authors, and deserves phylogeographic validation. The main conservation priority for P. adspersus in South Africa should be the protection of terrestrial habitat for adult foraging and aestivation around, and for juvenile dispersal and gene flow between, breeding sites. In Gauteng, the conservation of a P. adspersus metapopulation is critical, and could most likely be achieved in the northern region of this province. Populations in the Free State Province deserve improved protection given their reported genetic uniqueness. At local spatial scales specific threats (e.g. pollution) should be ameliorated, and long-term monitoring should be implemented to detect real population trends.
Thesis (PhD)--University of Pretoria, 2012.
Zoology and Entomology
Unrestricted

Two rare Banksia species, B. chamaephyton A.S. George and B. elegans Meissner, were the subject of this study. B. chamaephyton is gazetted as rare under the Wildlife Conservation Act of Western Australia and B. elegans has been recorded by various authors as restricted in range and habitat.Data were collected on the distribution, habitat, reproduction and fire responses of each species. Both were found to occur predominantly in the Irwin Botanical District. B. chamaephyton is found in low heath on sand over laterite and B. elegans in scrub or thickets on deep, yellow sands. Data on species co-occurring with B. chamaephyton were gathered for the purpose of identifying habitats with actual or potential populations of the rare species. Several species appeared to be reliable indicators.Both species are represented in areas set aside for conservation although some populations are vulnerable and their loss would considerably reduce the range of each species. Of particular concern are the southernmost populations of B. chamaephyton and the northernmost populations of B. elegans. The latter appears to represent a size variant within the species. Although neither species is currently endangered, it is recommended that B. chamaephyton remain a gazetted rare species and that consideration be given to the gazettal of B. elegans.Both species are xenogamous and probably bird-pollinated although pollination by small mammals is a possibility. Both also have very low fruit and seed set. In B. chamaephyton, this is probably related to resource availability but B. elegans possesses a malformed stigma which may prevent the normal reproductive process from taking place. Most populations of B. elegans are sterile. Further research into the sexual reproduction and propagation of B. elegans is recommended.Fire is important to both species. In B. chamaephyton, fire, together with subsequent wet/dry cycles, is necessary for seed release from the follicles. Seedling recruitment is negligible in B. elegans. Mature individuals of both species survive fire and in B. elegans fire stimulates root suckering. Autumn burns appear to be most suitable for recruitment in both species, preferably at a minimum interval of ten years.

Two rare Banksia species, B. chamaephyton A.S. George and B. elegans Meissner, were the subject of this study. B. chamaephyton is gazetted as rare under the Wildlife Conservation Act of Western Australia and B. elegans has been recorded by various authors as restricted in range and habitat.Data were collected on the distribution, habitat, reproduction and fire responses of each species. Both were found to occur predominantly in the Irwin Botanical District. B. chamaephyton is found in low heath on sand over laterite and B. elegans in scrub or thickets on deep, yellow sands. Data on species co-occurring with B. chamaephyton were gathered for the purpose of identifying habitats with actual or potential populations of the rare species. Several species appeared to be reliable indicators.Both species are represented in areas set aside for conservation although some populations are vulnerable and their loss would considerably reduce the range of each species. Of particular concern are the southernmost populations of B. chamaephyton and the northernmost populations of B. elegans. The latter appears to represent a size variant within the species. Although neither species is currently endangered, it is recommended that B. chamaephyton remain a gazetted rare species and that consideration be given to the gazettal of B. elegans.Both species are xenogamous and probably bird-pollinated although pollination by small mammals is a possibility. Both also have very low fruit and seed set. In B. chamaephyton, this is probably related to resource availability but B. elegans possesses a malformed stigma which may prevent the normal reproductive process from taking place. Most populations of B. elegans are sterile. Further research into the sexual reproduction and propagation of B. elegans is recommended.Fire is important to both species. In B. chamaephyton, fire, together with subsequent ++
wet/dry cycles, is necessary for seed release from the follicles. Seedling recruitment is negligible in B. elegans. Mature individuals of both species survive fire and in B. elegans fire stimulates root suckering. Autumn burns appear to be most suitable for recruitment in both species, preferably at a minimum interval of ten years.

The present Ph.D. thesis aimed to provide a better understanding of Juniperus macrocarpa and the habitat that it characterizes (Juniperus spp. habitat; European priority habitat) in Sardinian coastal dunes, as well as to achieve results useful to support in situ and ex situ conservation actions. In particular, the specific aims of the thesis were: (1) to analyse morphological variation in seeds of Mediterranean Juniperus taxa (at inter- and intraspecific level) and morphometric differences in J. macrocarpa seeds collected in different populations, seasons and sources; (2) to evaluate the effect of the collecting season, source, laboratory pre-treatments and temperatures on seed viability and germination of J. macrocarpa; (3) to investigate factors affecting seedling emergence, survival and growth of the species; (4) to explore the floristic variability of the habitat in Sardinia in relation to geographic, climatic and human variables, as well as the potential effect of human disturbance and sampling period on key plant parameters; and finally (5) to assess the conservation status of this habitat in Sardinia. In the first chapter, a statistical classifier for Mediterranean Juniperus taxa based on seed morphometric parameters analysed by image analysis techniques, was tested at interspecific, specific and intraspecific levels. Analysed seeds came from galbules of Juniperus taxa collected from different regions of the Mediterranean Basin and galbules of J. macrocarpa collected in 2010 from four Sardinian populations, in two seasons and in plants and soil. Two taxonomic treatments for Juniperus genus (Flora Europaea and The Plant List) were compared and inter-population, seasonal and source variability in seed morphology were analysed. High percentages of correct identification were reached for both taxonomic treatments at specific and intraspecific level and from the comparison among taxa of the J. oxycedrus, J. communis and J. phoenicea complexes. Moreover, this statistical classifier discriminated J. macrocarpa seeds collected in spring better than those collected in autumn, but it seemed not to be able to discriminate those seeds collected from plants and soil, nor those ones collected in different populations from the same geographical region. In the subsequent chapter, seed viability and germination phenology of J. macrocarpa were investigated. For this purpose, ripe galbules in four localities and in two seasons, both from plants and soil, were collected. In order to verify the presence of physiological dormancy, warm (W) and cold stratification (C), two combinations of them (W+C and C+W), and no pre-treatment (control) were applied. After pre-treatments, seeds were incubated in a range of constant (10–25°C) and alternating (25⁄10°C) temperatures. Seed viability was low (ca. 40%) and the source (plant or soil) had not a significant effect on it, but it varied significantly according to season, showing lower percentages for seeds collected in autumn than in spring. Seed germination was low (ca. 10%), the control and W were the most effective on stimulating germination, while C negatively affected germination. The best temperatures for germination were 15 and 20°C and seeds collected in spring showed higher germination percentages (ca. 11%) than in autumn (ca. 7%). Seeds of J. macrocarpa are dormant and the results of this study suggested the presence of secondary dormancy induced by cold stratification. The germination phenology all along the dispersal season (from autumn to spring) was illustrated, as well as the potentiality of this taxon to create a soil seed bank. In the third chapter, factors affecting emergence, survival and growth of J. macrocarpa seedlings, were investigated. For this study, permanent plots were placed and periodically monitored. Within them, besides seedling parameters (emergence, survival and growth), several biotic and abiotic variables (solar radiation, tree cover, herbaceous plus scrub cover, distance from the closer J. macrocarpa female, number of galbules on the soil and event number of herbivore trace) were measured. Linear mixed-effects models were used to test the relative importance of different groups of explanatory variables on seedling parameters. A total of 536 seedlings were marked, most of which emerged in winter. The "microclimate" was the best fit model explaining emergence, highlighting the positive relation between the number of emerged seedlings and tree cover. Survival was very low and most of the seedlings died in the first months from emergence, reaching the highest mortality rate in the first summer. High values of both herbivory and solar irradiation increased mortality risk. Our results confirmed that J. macrocarpa is a slow growing species, and no seedlings reached the subsequent size class. Moreover, growth depended on suitable microhabitats, and in particular it was positively related to tree cover, hours of sunlight, and herbaceous plus scrub cover. Despite these relevant results, long-term studies are needed to identify key issues in the life cycle of J. macrocarpa (e.g. germination, fitness, and recruitment). In the last chapter, the floristic variability of Juniperus spp. habitat in Sardinia in relation to geographic, climatic and human variables was explored. Two data sets were created: the first one by inputting phytosociological relevés available in literature and our own relevés; the second one by including for each relevé geographic, climatic and floristic variables, as well as sampling period and human disturbance as categorical variables. The floristic composition differed among sites and this variation was mainly ruled by a latitudinal gradient linked to a climatic gradient. Regarding the results of key parameters in the evaluation of the habitat quality, floristic richness was positively influenced by low and medium level of human disturbance; the endemic taxa cover was positively related to a medium level of human disturbance, while the alien taxa cover was positively related to recent samplings. The conservation status of Juniperus spp. habitat in Sardinia following the IUCN protocol we also assessed. Preliminary results showed that this habitat should be considered as endangered (EN) at a regional level. In conclusion, our results gave new findings for the recovery and conservation planning of the species and the habitat under study. Specifically, we found that spring was the best season for seed collection. We also suggest: autumn as the period for planting or sowing, with planting being preferable to sowing; shielding plants from solar radiation under canopy; the application of techniques such as organic blanket when sowing is the selected option. In addition, in order to improve the conservation status of Juniperus spp. habitat, we advise management measures such as the eradication of alien taxa, as well as interventions aimed to reduce human impact on the dune systems.

Includes bibliographical references.
Providing an economic case for establishing new protected areas and demonstrating how conservation enhances human well-being is becoming necessary to reinforce moral arguments for biodiversity protection. Accordingly; this study aimed to assess whether the spatial distribution of priority areas changes in accordance with gains in economic-efficiency when ecosystem service benefits are explicitly considered. Using the site-selection software Marxan, priority areas for South Africa were identified under four scenarios, two of which incorporated a spatial cost benefit analysis of the opportunity costs and ecosystem service benefits associated with conservation. Additional scenarios assessed how reserve design and costs changed when communal-land agriculture and resource use were weighted to account for the social costs of conservation. Opportunity costs were spatially variable and greatest in regions where mixed commercial farming was practiced. Economic benefits exceeded costs in the western interior, northern regions and along the eastern coastline. These areas contracted when ecosystem service benefits were more conservatively estimated by applying the principle of additionality. There was minimal to moderate spatial agreement between the scenarios (0.12 < κ < 0.55).When economic benefits were considered, areas that made more economic sense from a conservation management perspective were prioritized. These changes in spatial distribution were associated with gains in economic efficiency. The cost: benefit ratio was ca. 10 times greater than when no economic variables were considered (scenario 1 = 10.44 vs. scenario 4 = 1.15). When heavy weightings (> 100) were applied, the reserve systems became dispersed (R = 0.91 (for weighting factor of 10), R = 0.52 (for weighting factor of 1000)) in the former homelands and more costly overall (difference of R2.95B between the extremes). Considering the economic benefits of conservation changes the spatial distribution of priority areas and improves their economic efficiency. Disregarding economic benefits may compromise the implementation potential of priority areas, particularly when the economic benefits of competing land-uses are brought to the table. Furthermore, it is important to explicitly consider the social costs of conservation and consider resettlement or compensation costs among the trade-offs.

Thesis: S.M., Massachusetts Institute of Technology, Department of Biology, 2015.
Cataloged from PDF version of thesis.
Includes bibliographical references (pages 54-59).
Muscleblind (Mbl) is an evolutionarily conserved family of proteins involved in many aspects of RNA metabolism, including alternative splicing. Disruption of Muscleblind in several animals lends to a variety of defects and disease, including the multi-systemic disorder Myotonic Dystrophy (DM). Though much is known about the involvement of Muscleblind in DM, there is much basic knowledge of the protein's function to be discovered. We approach this problem by exploring the functional conservation of a diverse subset of Muscleblind homologs. The functions of Muscleblinds from a basal metazoan, Trichoplax adhaerens, a primitive chordate, Ciona intestinalis, and the model organisms, Drosophila melanogaster and Caenorhabditis elegans were compared to human Muscleblind-like (MBNL). The zinc finger RNA-binding domains are the most conserved region between homologs, suggesting a conserved role in RNA binding and splicing regulation. To test this, we used splicing reporter assays with validated human MBNL-regulated mini-genes and performed RNA sequencing experiments in mouse embryonic fibroblasts (MEFs). Additionally, we accessed the subcellular localization of the homologs to determine conservation of extra-nuclear functions. Reporter assays in HeLa cells showed that the homologs can positively and negatively regulate splicing. Our RNA-seq experiments led us to discover hundreds of endogenously regulated splicing events, including the identity of the transcripts, direction of splicing regulation, types of splicing events, and the magnitude of alternate exon inclusion in the spliced mRNAs. Additionally, we identified a spectrum of splicing events, from those uniquely regulated by a single Muscleblind, to events regulated by all Muscleblinds, and, characterized the variation in splicing activity that exists between homologs. A subset of events regulated by mammalian Muscleblind were oppositely regulated by non-mammalian homologs. Muscleblinds show nuclear-cytoplasmic localization, which suggests conservation in extra-nuclear functions. In conjunction with exon and intron sequences, this information provides a future tool to discover conserved and novel RNA regulatory elements used by diverse Muscleblinds to regulate splicing and in putative cytoplasmic functions. These data could also be used to determine functionally important residues in Muscleblind proteins and help us better understand the protein family.
by Julia C. Oddo.
S.M.

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Biology, 2012.
Cataloged from PDF version of thesis.
Includes bibliographical references (p. 21-23).
Exon scrambling is a phenomenon in which the exons of an mRNA transcript are spliced in an order inconsistent with that of the genome. In this thesis, I present a computational analysis of scrambled exons in human and mouse. RNA-seq data was mapped to the genome and all unaligned reads were subsequently mapped to a database of all possible exon-exon junctions. Eight conserved genes were found to undergo scrambled splicing in both species. In several cases, not only the gene was conserved, but the particular exons involved were conserved as well. Reading frame was preserved in just over half of the events, indicating that although some transcripts may be translated into protein, some may be non-functional or may play a regulatory role. The introns flanking scrambled exons were significantly longer than average, providing clues to the mechanism for this abnormal splicing pattern. The results of this study demonstrate that presence of scrambled transcripts in the cell is infrequent, but can be conserved over tens of millions of years of evolution, suggesting it has a biological function.
by Monica L. Hamilton.
S.M.

The efficacy of intensive rotational targeted grazing (IRTG) for suppression of the invasive shrub, multiflora rose (Rosa multiflora) was investigated in upstate New York. Sheep stocked at high density were rotated through a circuit of enclosures at a frequency of 3-d per enclosure, from May-September, 2011 and 2012. The photosynthetic surface areas (PSA) and vitality of R. multiflora plants were evaluated before (May 2011) and after treatment by grazing (Sept 2011). Changes over time were compared with similar measurements of ungrazed plants. Species richness (S) was estimated in each enclosure before (May) and after (September) treatment. PSA in grazed enclosures declined by 56.8% over the 2011 season and by 62.5% during the 2012 season. One year after ITRG treatment, healthy R. multiflora plants in grazed enclosures had declined by 91% and unhealthy and dead plants had increased by more than 200%. The distributions of healthy, unhealthy and dead plants, in grazed and ungrazed enclosures, though not different before treatment (chi square goodness of fit test; p>0.05?? were different one year later (p<0.001). Mean S in grazed enclosures increased by 27% over the season and by the end of the study, S was 12% higher than ungrazed enclosures. Evidence of stress in R. multiflora (clumping, dwarfing and reddening of leaves) at the end of the 2011 season led me to investigate the possible presence of rose rosette disease (RRD) during 2012. Potential stress was confirmed in plants experiencing leaf reddening. Chlorophyll a concentrations were significantly lower in red than green leaves (Student?s t = 5.20, df=28, p<0.001). Not unexpectedly, Normalized Difference Vegetative Index (NDVI) lso differed in red and green leaves (Student?s t = 2.76, df=32, p<0.01). Green leaves had higher dry weights than red leaves (Student?s t=14.13, df=151, p<0.001). Wool from the sheep, and R. multiflora leaf and petiole samples were collected to determine if the eriophyid mite, Phyllocoptes fructiphilus, a vector for RRD was present. No significant evidence of P. fructiphilus in leaf and petiole (Mean=0.00 N=414 SD=.71) or wool samples (Mean=0.00 N=11 SD=0) was found. This was unexpected, although it would only take one mite to be the vector if that particular mite was carrying the rose rosette virus. Further studies would be required to test whether rose rosette was confirmed in this population. Visual evidence of RRD symptoms were more prevalent in grazed enclosures than ungrazed locations, and a greater decline in grazed enclosures was clear.

Includes bibliographical references.
The Northern Rockhopper Penguin Eudyptes moseleyi is listed as Endangered due to an estimated 57% decrease in breeding numbers over the past 37 years. Approximately 85% of the global population breeds at the Tristan da Cunha archipelago (Tristan, Inaccessible and Nightingale Islands) and nearby Gough Island in the central South Atlantic Ocean. The population on Gough Island declined by 50-60% between 1982 and 2005, but in the Tristan da Cunha archipelago the population trend over the last few decades is believed to be stable despite long-term human exploitation (particularly egg collection on Nightingale Island in recent years).This study compares aspects of the breeding biology on Gough Island (where population numbers are decreasing) and Nightingale Island (where numbers are thought to be stable) based on data gathered from five colonies in the 2012/13 and 2013/4 breeding seasons. On Nightingale Island, breeding success was 6.5% lower and 40-day old chick mass 47% less(implying poor juvenile recruitment)compared to on Gough Island. Poor foraging conditions for birds on Nightingale Island is the most probable explanation for these results, and future studies should focus on the foraging locations used by birds on both islands. Additionally, egg collection practices on Nightingale Island may have had a negative impact on the population, and I recommend that the temporary ban on egg-collection at Nightingale Island is made permanent. It is also possible that the population on Gough Island is no longer in decline, or is declining for reasons unrelated to breeding success; to verify this and confirm the findings of this study, future population trends and chick fledging mass on both islands should be monitored over the long-term.

This thesis examines two potential conservation problems for a residential sub-population of ~75 bottlenose dolphins (Tursiops sp.) in Cockburn Sound, a small embayment within the southern metropolitan waters of Perth, Western Australia: (1) human-induced habitat change and (2) illegal feeding (i.e. unregulated provisioning) of dolphins. The work is important because Cockburn Sound is the most intensively utilised marine environment in Western Australia and industrial, commercial, and recreational uses of the area will intensify in coming decades. These considerations, coupled with the demographic and ecological vulnerability of residential populations of small cetaceans, suggested a risk of population decline without a more informed scientific basis for management. This study (2000 – 2003) complemented an earlier study of the Cockburn Sound dolphins (1993 – 1997) to provide a decade-long longitudinal study of the population. The original contributions of this study relate to: (a) the foraging ecology of dolphins;(b) the effects and mechanisms of human-dolphin interaction, particularly interactions based on unregulated provisioning; and (c) an integration of previous research and other information. Studies of the foraging ecology of dolphins within Cockburn Sound were undertaken between 2000-2 to determine the areas used by dolphins and their feeding behaviours so that the implications of human-induced habitat change could be assessed. These studies used belt transect sampling and event-specific sampling of foraging aggregations of dolphins to quantify the foraging habitat use of dolphins within the Sound and to characterise spatial and temporal patterns in aggregations of foraging dolphins. The results showed that the density of foraging dolphins varied significantly across habitats and that foraging aggregations consistently occur in an area known as the Kwinana Shelf during the austral autumn-spring period. The studies also suggested that the foraging ecology of dolphins in Cockburn Sound reflects the consistent utilisation of both: (a) low-density prey species (i.e. individual or weakly-schooling prey) and (b) high-density prey species (i.e. schooling species such as forage fish). These findings indicate that ecosystem-based conservations of the population should consider the conservation requirements of dolphin prey species and the ecological integrity of key foraging habitats like the Kwinana Shelf. Human-dolphin interactions based on the illegal feeding of dolphins in Cockburn Sound escalated between 1993 and 2003. By 2003, a total of 14 individuals exhibited behaviours indicative of conditioning to human interaction by food reinforcement, including some individuals that engaged in provisioning interactions on a chronic (i.e. long-term) basis. Observations of the effects of unregulated provisioning indicated that: (a) provisioned dolphins sustained increased higher rates of human-induced injury than non-provisioned dolphins and (b) provisioning was associated with substantial and enduring behavioural changes including changes in ranging and association patterns. Other observations of human-induced injury in Cockburn Sound included seven instances of calf entanglement. These findings indicate that the effects of illegal feeding and other forms of direct human-dolphin interaction (e.g. entanglement) could achieve biological significance for the population. The possible contribution of (a) human influences, (b) social learning, and (c) behavioural propensities (e.g. age and sex) on the acquisition of an attraction response to human provisioning was examined through logistic regression analysis using age, sex, use of high-boat density areas, and the number of close associates that were previously provisioned as predictor variables and the acquisition of an attraction response as the dependent variable. This analysis was supplemented by behavioural observations of interactions between provisioned and naïve individuals during provisioning interactions. The results supported three findings: (1) a relatively high level of exposure to human provisioners was a significant predictor for the acquisition of an attraction response by dolphins; (2) social learning contributed to the acquisition of an attraction response in those individuals that more frequently utilised high-boat density areas; and (3) the potential contribution of behavioural propensities relating to age and sex was uncertain. These conclusions suggest that the acquisition of an attraction response to human provisioning can best be understood as the outcome of a complex of interacting factors. The findings also indicate: (a) the management value of individual-specific and longitudinal data for the management of harmful human-wildlife interactions and (b) the potential for social learning to contribute to the development and persistence of these interactions. The findings of this study indicate that population decline in Cockburn Sound could be induced by: (1) a reduction in the Sound’s environmental carrying capacity or (2) mortality, injury, and behavioural changes resulting from interactions with humans. The potential for such a decline and evidence demonstrating the harmful effects of human activities on dolphins supports the application of preventative approach to the management of illegal feeding and entanglement and a precautionary approach to environmental impact assessments of proposed developments. Mitigation of direct human-dolphins like illegal feeding requires an enforcement and education program to encourage more responsible human attitudes towards interactions with dolphins. Research on the ecology and composition of finfish assemblages and the trophic structure of the Kwinana shelf would assist efforts to mitigate the impact of human-induced habitat change.

Conservation biology emerged as an activist discipline in the 1980s in response to increasing evidence that Earth is undergoing a biodiversity crisis. Building on foundations of biological science and applied resource management methods, this new discipline called upon its practitioners to both undertake scientific research to improve understanding of all species and ecosystems, and to take social and political action to protect and enhance endangered biodiversity. In the current era of declining budgets for biodiversity research and management, volunteer citizen science is gaining recognition as an important strategy for expanding and extending the work of embattled professional conservation biologists. New technologies such as handheld computers, GPS, GIS, interactive map services, and the internet, and the wide-spread availability, adoption and adaptation of these technologies by the general public, have created an environment where citizens can be rapidly mobilized to gather, process, and communicate data in support of conservation biology’s twin goals. In this thesis I explore citizen science within conservation biology and within the concept of the GeoWeb. I trace the history of citizen science in biology since the late 1800s to the current day, to better understand the practice and its contribution to conservation science. I find that citizen science is often employed to undertake research at large spatial scales, and that often location is a key attribute of the data citizens gather; as a result, the infrastructure and methods of the GeoWeb are fundamental to many citizen science projects. In the spirit of conservation biology, I pair my research of citizen science with the assembly of a set of best practices for increasing the impact of the practice on the conservation agenda, and then evaluate twelve current citizen science projects currently underway in British Columbia against these practices. I conclude that citizen participation in biological science furthers both of conservation biology’s goals: it both increases our body of knowledge about biodiversity, and helps to develop an informed and empowered constituency for conservation action and ecologically sustainable stewardship.

The genus Restrepia is well known to orchid enthusiasts but its micromorphology has not been described, and its pollination and breeding systems have not been investigated. The aim of this investigation was, therefore, to add to existing knowledge so that the resultant data could be used to facilitate ex situ conservation initiatives. A detailed electron microscopy study (SEM) of the floral organs was performed. This confirmed the structure of the dorsal sepal and lateral petal osmophores, their secretory nature together with that of the synsepal and the labellum. It was postulated how, by manipulating different labellar surface textures, the flower might use these ‘tactile guides’ to steer the insect (fly) through the flower. The cirrhi were postulated to help by destabilising the pollinator in flight, trapping it and bringing about pollination. The papillate structure of the calli was established and their optical properties investigated. Media comparison investigations established that Western medium supported the highest germination rates and, with the addition of banana supplement, the highest rates for seedling growth and development. This represented the first protocol for axenic germination of Restrepia in the literature (Millner et al., 2008) and provided a tested methodology for investigating breeding systems and producing Restrepia plant material for both scientific and horticultural purposes. Self-pollinations were found to produce fewer embryos compared to cross-pollinations. The operation of self-incompatibility (SI) was confirmed by the study of pollen tube growth which further confirmed the time interval between pollination and fertilisation. A time line from pollination/fertilisation to flowering was established. The type of SI in operation was best explained by gametophytic incompatibility. This demonstrated that it was possible to raise Restrepia hybrids and species from seed, by performing intraspecific crosses so helping to preserve them for posterity and relieve pressure on wild populations. Narrow endemic Restrepia species face combined threats from habitat loss, habitat degradation and problems of viable seed production due to the effects of SI and inbreeding depression (ID). Recently developed online resources, such as GeoCAT, were used to perform a Red List assessment in order to identify the degree of threat individual species faced, both globally and nationally. All species were classified as facing substantial levels of threat; although this was lessened for populations in protected habitats. Conservation is needed for cultivated collections as well as these wild populations by keeping alive existing knowledge and expertise in growing these species.

Reproductive science plays an important role in conservation biology. Quantitative studies of basic reproductive biology in wildlife are critical for the development of successful assisted reproductive technologies. Investigation of the volume regulatory mechanism of spermatozoa could produce options to improve the cryopreservation of spermatozoa and provide a non-hormonal contraceptive option for men, both of which could have significant impacts on global biodiversity preservation. Volume regulation of somatic cells involves the movement of osmolytes through various channels, including potassium channels. The potassium channels involved in volume regulation of human, monkey, and murine spermatozoa were investigated. Flow cytometry was used to gauge the sensitivity of the volume regulatory process of spermatozoa to various potassium channel inhibitors and a simultaneous hypotonic challenge. Channels potentially involved in regulatory volume decrease of spermatozoa varied with species but included voltage-gated (Kv) channels 1.4, 1.5, 1.7, 4.1, 4.2 and 4.3 as well as TWIK1, TWIK2, TASK1, TASK2, TASK3, TREK2 , and minK. The presence of some of these channels was confirmed by western blotting and immunocytochemistry. Changes in the motility patterns of human and monkey spermatozoa in the presence of potassium channel inhibitors during hypotonic stress were also observed, suggesting a relationship between volume regulation and motility. To evaluate potential organic osmolytes involved in, and compare effects of CPAs on, volume regulation, the isotonicity of murine epididymal spermatozoa was measured using a null point method. Spermatozoa were then exposed to high concentrations of various osmolytes and cryoprotective agents in isotonic medium to evaluate which compounds were able to penetrate the sperm plasma membrane. The osmotic responses of spermatozoa from strains of mice known to have spermatozoa of high (B6D2F1) and low (C57BL6) post-thaw fertility were compared during various osmotic challenges in various media. These experiments indicated that spermatozoa from B6D2F1 mice may have better volume regulation capabilities than spermatozoa from C57BL6 mice, suggesting that better post-thaw fertility of murine spermatozoa could be influenced by the volume regulatory process. The knowledge gained from these experiments could contribute to improved sperm handling and preservation techniques and be used to develop non-hormonal male contraceptives based on inhibiting volume regulation.

The present study primarily examined habitat selection in the noctule bat by comparing used resources with samples of available resources. The distribution of individual bats of different reproductive status was also investigated, in relation to resources, to enable the prediction of future events under different habitat management scenarios. Individual bats were radio tracked to determine foraging and roosting habitat preferences in a cultural landscape. Noctules consistently preferred to forage over broadleaved woodland and pasture rather than arable land and moorland. A comparison of habitat use and foraging activity demonstrated that non-lactating bats used less preferred habitats significantly more than lactating bats. However, there was little difference in the timing of foraging activity or in the distances traveled to foraging grounds between the two groups. Roosting requirements were identified using data from three separate study sites and intraspecific roosting behaviour was investigated at the radio-tracking site. Noctules consistently selected old woodpecker holes that were larger, further from the ground and in more open situations. Lactating bats changed roosts less frequently and generally occupied one specific roost, which was larger than the other roosts used by the same colony. The echolocation calls used by noctules are particularly suited to monitoring using bat detectors. Formal evidence that noctule calls could be accurately identified from field recordings was obtained by comparing the calls from tracked bats with calls recorded from Leisler's bats.

RAPD was used to assess genetic diversity among 18 populations of Talbotiella gentii, a ceasealpnoid, legume and an endemic rare species in Ghana in order to adopt proper conservation measures to prevent the species from extinction. Cluster analysis and correspondence analysis showed a clear distinction between populations into there major groups based on geographical origin. A total of 81 polymorphic bands were generated from 8 primers and used in the analysis. Amova analysis showed that 94.05% of the genetic variation was partitioned among populations while only 5.95% was found within population. Possible reasons for the high genetic differentiation (PHIst= 0.941) and the low levels of genetic variation within populations are inbreeding and genetic drift. The study also focused on the reproductive biology of Talbotiella from flowering stage through to seed germination and seedling survival to identify weak points that might contribute to its rarity and impeded its conservation. Talbotiella flowers from late October and fruit ripening starts in late January. Fruit abortion was found to be high; outcrossing hand pollination increased fruit and seed set, seed mass, seed germination and seedlings survival. Air sampling at 3 populations of Talbotiella using 3 Agar media was carried out to find out the prevalence of fungi. Out of 17 genera of fungi observed, Fusarium verticilloides was found to be dominant in Talbotiella populations and mainly occupies the stigmatic surface of Talbotiella. Fungal infestation was found to interfere with germination of pollen on stigmatic surface of the species. The results indicate that conservation strategies should focus on preserving all populations in order to capture genetic variation among populations.

The Blue Mountains Water Skink (Eulamprus leuraensis), restricted to the endangered habitat of highland peat-swamps, is known from fewer than 60 isolated sites in the Blue Mountains region of south-eastern Australia. The sole endemic vertebrate of the region, this scincid lizard is imperilled by many threats. From three years of field surveys, I show that E. leuraensis live almost exclusively within swamps, with very few inhabiting the swamp margins and none recorded in the surrounding woodland. Paradoxically, this endangered species appears to be the most abundant vertebrate in these swamps. My surveys show that urbanisation and frequent major fires both reduce the abundance of these skinks, but do not extirpate them. A longer period of time since a major fire, conversely, increases the abundance of this reptile. Groundwater loss and alterations in surface water chemistry extirpate populations of this species: its restriction to groundwater-dependent swamps renders it highly sensitive to habitat degradation through hydrological disturbance. To conserve E. leuraensis in the wild, we need to protect its swamp habitat from the impacts of urbanisation, intensified fire regimes, reduced groundwater, water pollution and longwall mining. The conservation message for management authorities is clear: ‘protect the habitat, protect the skink.’

This thesis examines two potential conservation problems for a residential sub-population of ~75 bottlenose dolphins (Tursiops sp.) in Cockburn Sound, a small embayment within the southern metropolitan waters of Perth, Western Australia: (1) human-induced habitat change and (2) illegal feeding (i.e. unregulated provisioning) of dolphins. The work is important because Cockburn Sound is the most intensively utilised marine environment in Western Australia and industrial, commercial, and recreational uses of the area will intensify in coming decades. These considerations, coupled with the demographic and ecological vulnerability of residential populations of small cetaceans, suggested a risk of population decline without a more informed scientific basis for management. This study (2000 - 2003) complemented an earlier study of the Cockburn Sound dolphins (1993 - 1997) to provide a decade-long longitudinal study of the population. The original contributions of this study relate to: (a) the foraging ecology of dolphins;(b) the effects and mechanisms of human-dolphin interaction, particularly interactions based on unregulated provisioning; and (c) an integration of previous research and other information. Studies of the foraging ecology of dolphins within Cockburn Sound were undertaken between 2000-2 to determine the areas used by dolphins and their feeding behaviours so that the implications of human-induced habitat change could be assessed. These studies used belt transect sampling and event-specific sampling of foraging aggregations of dolphins to quantify the foraging habitat use of dolphins within the Sound and to characterise spatial and temporal patterns in aggregations of foraging dolphins. The results showed that the density of foraging dolphins varied significantly across habitats and that foraging aggregations consistently occur in an area known as the Kwinana Shelf during the austral autumn-spring period. The studies also suggested that the foraging ecology of dolphins in Cockburn Sound reflects the consistent utilisation of both: (a) low-density prey species (i.e. individual or weakly-schooling prey) and (b) high-density prey species (i.e. schooling species such as forage fish). These findings indicate that ecosystem-based conservations of the population should consider the conservation requirements of dolphin prey species and the ecological integrity of key foraging habitats like the Kwinana Shelf. Human-dolphin interactions based on the illegal feeding of dolphins in Cockburn Sound escalated between 1993 and 2003. By 2003, a total of 14 individuals exhibited behaviours indicative of conditioning to human interaction by food reinforcement, including some individuals that engaged in provisioning interactions on a chronic (i.e. long-term) basis. Observations of the effects of unregulated provisioning indicated that: (a) provisioned dolphins sustained increased higher rates of human-induced injury than non-provisioned dolphins and (b) provisioning was associated with substantial and enduring behavioural changes including changes in ranging and association patterns. Other observations of human-induced injury in Cockburn Sound included seven instances of calf entanglement. These findings indicate that the effects of illegal feeding and other forms of direct human-dolphin interaction (e.g. entanglement) could achieve biological significance for the population. The possible contribution of (a) human influences, (b) social learning, and (c) behavioural propensities (e.g. age and sex) on the acquisition of an attraction response to human provisioning was examined through logistic regression analysis using age, sex, use of high-boat density areas, and the number of close associates that were previously provisioned as predictor variables and the acquisition of an attraction response as the dependent variable. This analysis was supplemented by behavioural observations of interactions between provisioned and naive individuals during provisioning interactions. The results supported three findings: (1) a relatively high level of exposure to human provisioners was a significant predictor for the acquisition of an attraction response by dolphins; (2) social learning contributed to the acquisition of an attraction response in those individuals that more frequently utilised high-boat density areas; and (3) the potential contribution of behavioural propensities relating to age and sex was uncertain. These conclusions suggest that the acquisition of an attraction response to human provisioning can best be understood as the outcome of a complex of interacting factors. The findings also indicate: (a) the management value of individual-specific and longitudinal data for the management of harmful human-wildlife interactions and (b) the potential for social learning to contribute to the development and persistence of these interactions. The findings of this study indicate that population decline in Cockburn Sound could be induced by: (1) a reduction in the Sound?s environmental carrying capacity or (2) mortality, injury, and behavioural changes resulting from interactions with humans. The potential for such a decline and evidence demonstrating the harmful effects of human activities on dolphins supports the application of preventative approach to the management of illegal feeding and entanglement and a precautionary approach to environmental impact assessments of proposed developments. Mitigation of direct human-dolphins like illegal feeding requires an enforcement and education program to encourage more responsible human attitudes towards interactions with dolphins. Research on the ecology and composition of finfish assemblages and the trophic structure of the Kwinana shelf would assist efforts to mitigate the impact of human-induced habitat change.