Tesi sul tema "Forest biodiversity"

Thesis (Ph. D.)--University of New South Wales.
Photocopy of original held in Defence Academy Library, University College, University of New South Wales. Includes bibliographical references. Also issued online.

Mestrado em Gestão da Floresta e dos Recursos Naturais no Mediterrâneo (MedFor) - Instituto Superior de Agronomia
Deforestation and forest degradation are global challenges that negatively affect forests, ecosystem services and biodiversity. The concept of ‘Forest Landscape Restoration’ has emerged as a contribution to address these challenges and recover forests, restore biodiversity, improve ecosystem services and human well-being, thus contributing to the Sustainable Development Goals. Forest landscape restoration may create opportunities for biodiversity conservation, reduction of erosion, water regulation, and supply of food and wood products. Today, Forest Landscape Restoration projects are applied with a wide variety of approaches. However, there is still a need to assess how this concept is being put into practice by different initiatives. This includes getting information on project locations, project main objectives, methods, implications on biodiversity and ecosystem services, nutritional benefits of trees, and evaluate how the selection of tree species is done. In order to provide a complete picture of forest landscape restoration practices around the world, this research focused on obtaining information from various projects through an online survey aimed at practitioners of forest restoration worldwide. Responses from 47 FLR projects showed that most restoration activities targeted are currently undergoing in the tropics. Increasing vegetation cover and recovering biodiversity were the most common objectives. About 60% of the projects used a mixture of artificial and natural regeneration. According to the responses, in most of the projects (75%), 100% of the planted species were native to the project site. The diversity of planted species was on average of 1 to 3 species per hectare. From the total list of 141 responses, 131 planted tree species were derived, threatened species covered a small proportion of 17%. In general, FLR projects did not plant any edible tree species. It was also found that project managers and local communities are often involved in species selection, in most cases both men and women
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Thesis (doctoral)--Swedish University of Agricultural Sciences, 2008.
Thesis documentation sheet inserted. Includes appendix of reprints of five papers and manuscripts co-authored with others. Includes bibliographical references. Also partially issued electronically via World Wide Web in PDF format; online version lacks appendix of papers.

Globally, biodiversity is declining due to loss, fragmentation and degradation of habitat, which undermines ecosystem functioning and therefore threatens also the ability of ecosystems to supply ecosystem services. Moreover, there is a need for adapting to climate change as well as securing the supply of energy, which have led to a shift in energy consumption from fossil fuel to renewables, especially biomass, which in turn put increasing pressure on ecosystems and biodiversity. In Sweden, forest bioenergy has an important role, and high forest biomass production is an important societal objective. Intensified forestry could increase the biomass production through monocultures of native or introduced tree species as well as forest fertilization. However, due to negative effects on natural forest structures and processes, a more intensive forestry could be detrimental to forest biodiversity. The balance between energy demand and the long-term capacity of ecosystems to supply goods and services as well as support biodiversity is therefore crucial. The existing energy models and research have relatively low concerns on land use, landscape and biodiversity, comparing with high enthusiastic on energy economics, climate change and greenhouse gas emission research. Consequently, it would be difficult to provide comprehensive decision support by using only these economy and climate change oriented tools. However, ecological assessment models and multi-criteria approaches exist with great potential for linking with suitable energy models. This will enable the development of more comprehensive decision support tools for assessing future energy scenarios, integrating main policy concerns when assessing renewable energy options. The research was based on a survey on existing energy models and a case study of forest biomass extraction in Kronoberg, a region in southern Sweden. The aim of this project was to develop and test methods for integrated the sustainability assessment of forest biomass extraction for bioenergy purposes by incorporating effects on biodiversity. Forest growth was simulated under two management scenarios: Even-aged-forestry (EAF) and continuous-cover-forestry (CCF), in a time period between 2010-2110. The GIS-based approaches for assessment of biomass impacts on biodiversity involved an ecological network assessment of prioritized ecological profiles across the landscape under the two scenarios.

QC 20160111

Thesis (doctoral)--Swedish University of Agricultural Sciences, 2002.
Abstract inserted. Appendix includes reprints of a published paper and three manuscripts, each co-authored with a different author. Includes bibliographical references. Also partially issued electronically via World Wide Web in PDF format; online version lacks appendix.

Neotropical forests have experienced high rates of biodiversity loss as a result of burgeoning land-use changes. Habitat conversion into cropland, pastures, and more recently hydroelectric lakes, are leading drivers of forest loss and fragmentation of pristine forests in the world’s most biodiverse region. This thesis aims to improve our understanding of the impacts of habitat fragmentation on biodiversity loss in Neotropical forests by evaluating the patterns of floristic changes and vertebrate extinctions in forest patches. Two approaches at different scales were conducted. First, a systematic literature review was carried out on the effects of fragmentation on Neotropical primates at a continental-scale. Second, biodiversity inventories were conducted on medium and large bodied vertebrates (including mammals, birds and tortoises) and trees ≥10 cm diameter at breast height at 37 islands and three continuous forest sites within the Balbina Hydroelectric Reservoir in Brazilian Amazonia. Patch area was a key driver of species persistence for all study taxa, yet other factors were also important. Hunting pressure exerted a strong influence on patterns of primate persistence within 760 fragments, and edge effects, including edge-related ground-fires, were the main predictors of floristic transitions using data from 87 quarter hectare forest-plots at Balbina. Additionally, matrix composition and species life-history traits played a key role in explaining patterns of species persistence. This study therefore highlights the importance of considering anthropogenic stressors in assessing the effects of land-use change to explain patterns of species persistence in forest patches, aside from including parameters related to the matrix and ecological life history traits of focal species. As conservation recommendations, prioritising large (>100 ha) patches, increasing their protection, and enhancing connectivity of surrounding habitats becomes clearly important. For future Amazonian dams, it is recommended that engineers should consider the overall topography of planned reservoirs to maximise landscape connectivity and/or reject plans targeting unfavourable river basins.

This study seeks to investigate whether the biodiversity conservation of the Sinharaja rainforest in Sri Lanka can be economically justified solely in terms of its non-timber forest products (NTFPs) extraction potential as claimed by some recent research. A variety of methods and techniques were deployed including a botanical inventory survey, a crosssectional ethnobotanical survey, an ethnobotanical log-book survey and an ethnozoological survey. Several aspects relating to the NTFPs use: a) valuing the total inventory stock, the total extractable stock limit, the potential flow and actual flow; b) estimating the wild meat flow; c) seasonality of harvesting; d) sustainability issues; e) influence of phytosociological characteristics; f) influence of socio-economic characteristics; and g) forest accessibility; and h) market accessibility were investigated. Biophysical and socio-economic factors influencing the NTFPs value were investigated using a regression analysis. The impact of the NTFPs extraction on the regeneration of the natural population was investigated using three forest sites, a proximal site, a distant site, and a logged forest. The local peoples' perception about the sustainability of NTFPs harvesting was analysed using logit regression analysis. A geographic information system was used to investigatet he influenceo f accessibilityt o the forest and to the marketplace from the villages on the forest products flow. Finally, the NTFPs value was compared with alternative land-clearance use and timber use values. The results indicate that the NTFPs extraction value is insufficient on its own to economically justify the rainforest biodiversity conservation in Sri Lanka, and perhaps elsewhere. There is also some doubt about the long term sustainability of forest products extraction. The study concludes that the rainforest conservation will have to be justified by a full total economic value (use and non-use values) appraisal, together with other scientific and ethical reasoning and cannot be promoted solely on the basis of non-timber extraction value.

Aims: We aimed to enhance the conservation of forest biodiversity investigating: (i) The suitability of sampling methods for assessing patterns and trends of plant diversity; (ii) The effects of forest management and abandonment on biodiversity. Main study area: Foreste Casentinesi National Park (Italy). Methods: (i) We generated a georeferenced data set by assembling the available forest vegetation data for the study area, to investigate their spatial and temporal patterns. Then, we analyzed the consistency between preferential and probabilistic samplings. Further, we performed a resurvey study based on the oldest vegetation data in the data set. (ii) We analyzed the effects of management vs. abandonment of mountain beech forests on vascular plants and epiphytes. Finally, we compared richness and functional diversity metrics in capturing the effects of management-related habitat factors on biodiversity, analyzing European beech forests in Denmark. Results: (i) The preferential survey provides a biased estimation of patterns and trends of plant diversity, while a probabilistic method is more statistically representative, but it may fail to record important biodiversity features. Therefore, both sources of information should be considered to maximize the effectiveness of plant diversity assessment and monitoring. Structural and compositional dynamics assessed in the resurvey study reflect a widespread process of abandonment of mountains in the second half of 20th century. (ii) Different species groups show contrasting responses to management and abandonment and at present the occurrence of conservation-relevant species results a relevant metric for planning and evaluating conservation actions, especially for less studied organism groups. Conclusions: The use of proper, and standardized, sampling methods and metrics for biodiversity assessment is baseline for an effective conservation planning. A multi-taxon approach is highly recommended to avoid misleading conclusion for conservation. Further studies to identify suitable indicators of overall biodiversity may support rapid assessment methods for practical conservation.

Bibliography: leaves 86-97.
Lepfodon smithii (Leptodontaceae) and Pterogonium gracile (Leucodontaceae) are widespread and disjunctly distributed moss species, that in South Africa are confined to forest patches believed to be relics of vast forests that existed before the Pleistocene glaciation period. These two species exhibit similar distribution and ecologies and frequently co-occur. Wardia hygrometrica is a southwestern Cape endemic that is restricted to streams within the kloofs that the forests generally occupy. In an attempt to trace the species histories and their subsequent colonization of forest patches, two molecular markers, internal transcribed spacer (ITS) nuclear rDNA and trnL-F cpDNA were employed.

Currently, existing European beech forests (Fagus sylvatica L.) are scarce and fragmented across vast parts of their potentially natural distribution. About 25 % of the global range of beech forests is located in Germany. Thus, Germany has a particular responsibility to integrate biodiversity conservation aspects into beech forest use. In this thesis, the influence of naturalness-promoting management on forest structure and breeding birds was investigated – in comparison to management without a biodiversity focus (different management) and forests sites that have been unmanaged for different periods of time (recently: unmanaged for 14-32 years as of 2012, and long-term: unmanaged for 65 years or since at least 1900). With a total area of 714 ha, 22 study sites located in the northeastern part of Germany were studied. Forest structure was studied using forest development phases (FDPs), which divide the forest life cycle into different periods. FDPs are characterized by a defined combination of five structural parameters such as canopy cover, diameter at breast height, tree height, regeneration cover and deadwood amount. FDPs were mapped during the winters of 2012 and 2013 according to a dichotomic decision tree. Breeding bird abundances were determined in 19 study sites and each study site was mapped 10 times between March and July of the same years using a territory mapping method. FDP patterns such as proportions, patch sizes, distances between patches of the same FDP, evenness, FDP transition within a decade and transition diversity, as well as bird abundances and development of bird densities within a decade were analyzed. Study sites under naturalness-promoting management differ clearly from differently managed sites and they are comparable or develop similarly to (long-term) unmanaged stands regarding FDP patterns. This also applies for the composition of the breeding bird community and the development of breeding bird species within a decade. The effect of naturalness-promoting management within the last decade is strong as evidenced by: significant decreases in FDP patches in size, the development of FDP richness towards a complete set; the comparability of transition proportion and transition diversity with long-term unmanaged sites (for former gaps, regeneration phase, early-, mid- and late optimum phase as well as disintegration phase); the higher total abundances of all breeding birds as compared with differently managed and recently unmanaged sites; and the highest number of increasing bird species amongst all management types. Further, the occurrence of breeding birds is linked to FDPs. On the one hand, the breeding bird community has a strong preference for FDPs of later-stages such as the terminal and disintegration phases. On the other hand, every bird species has its own set of preferred and avoided FDPs and every FDP has several bird species preferring it. Thus, a complete set of all FDPs at small scale is necessary for the habitat requirements of birds inhabiting beech forests. In conclusion, 1) the positive impact of naturalness-promoting management on forest biodiversity is already detectable after a decade and 2) FDPs are a suitable indicator can be used as an innovative indicator for monitoring the impact of forest management on biodiversity.

As the doubling time of the global human population decreases, increasing emphasis is placed on sustainable development by both policy makers and scientists. Sustainable forest management is one part of the overall picture of sustainable development. One method to assess sustainable forest management is through the use of criteria and indicators. Criteria represent sustainable management goals. Indicators are measurable quantities that designate whether the goals are being met. The maintenance of forest health and vitality is a criterion of the Montréal Process Criteria and Indicators for the Conservation and Sustainable Management of Temperate and Boreal Forests. Measures of air pollution, forest disturbance, and change in ecological integrity provide indicators of how well forest health and vitality are being maintained. Using national databases, I assess air pollution in the United States, demonstrate the use of epidemiological approaches to examine forest disturbances, and develop an analytical technique to identify gaps and target priorities in reserve networks. The analyses in this dissertation offer new approaches to large-scale analysis of Montréal Process Criteria and Indicators. The results can be summarized as follows. (1) From 1994 through 2000 air pollution was highest in the northeastern United States and the oak-hickory and loblolly-shortleaf forest type groups were consistently exposed to more air pollution than other forest types. Conversely, the western white pine and larch forest type groups were consistently exposed to less air pollution than all other forest types. (2) Examination of the southeastern United States revealed high rates of forest fragmentation in the piedmont and coastal plain region. In the Pacific North west, insect and pathogen activity was analyzed and recurring clusters of high rates of activity were identified. (3) Although protected areas of the Douglas-fir forest type group occurred throughout much of the species range, most existed in colder and drier parts of the range. To conserve representative habitats, future conservation efforts would be most effective in warmer and wetter areas of western Oregon, northwestern Washington, and northwestern California.

Climate change is expected to drastically change the environmental conditions which forests depend. Lags in tree species movements will likely be outpaced by a more rapidly changing climate. This may result in species extirpation, a change in forest structure, and a decline in resistance and resilience (i.e., the ability to persist and recover from external perturbations, respectively). In the northern Great Lakes region of North America, an ecotone exists along the boreal-temperate transition zone where large changes in species composition exist across a climate gradient. Increasing temperatures are observed in the more southern landscapes. As climate change is expected to substantially affect mid-continental landscapes, this region is especially vulnerable to climate change. My research assessed the effects of climate change under business as usual (BAU) management as well as alternative management strategies. To do so, I simulated forest change in two landscapes (northeastern Minnesota and northern lower Michigan) under three climate change scenarios (current climate, low emissions, and high emissions), and four management scenarios (BAU, modified silviculture, expanded reserves, and climate suitable planting) with a spatially-explicit forest simulation model from year 2000 to year 2150. Specifically, I explored how climate change would affect relationships between tree species diversity and productivity; how expanded reserves and modified silviculture may affect aboveground biomass (AGB) and species diversity; how climate suitable planting may affect functional diversity, and AGB; and how alternative management may affect the resistance and resilience of forests to multiple disturbances interacting with climate change. Under the BAU management scenario, I found that current and low emissions climate scenarios did not affect the relationship between species diversity and productivity; however, under a high emissions climate scenario, a decline in simulated productivity was coupled with a stronger positive relationship between diversity and productivity. Under the high emissions climate scenario, overall productivity declined in both landscapes with specific species declines projected for boreal species such as balsam fir (Abies balsamea) and black spruce (Picea mariana). Under alternative management scenarios, I simulated a limited ability to increase tree species and functional diversity, AGB, and net primary productivity under climate change. The limits of management were especially apparent under the high emissions climate scenario. In a novel approach to measuring resilience, I plotted the recovery of both initial species composition and AGB to stochastic fire events for each simulation. This approach assessed both a general response (i.e. AGB) with a more specific response (i.e. species composition). My results suggest that climate change will reduce the resilience of northern Great Lake forest AGB and species composition and that management effects will be largely outweighed by the declines expected due to climate change. My results highlight the necessity to consider even more innovative and creative solutions under climate change (e.g., planting species from even further south than I simulated).

This study reports forest structure, regeneration and the soil properties from unlogged and logged forest in the Bulungan Research Forest, Malinau District, East Kalimantan, Indonesia. Four sites were compared by using four 1-ha replicate plots in each of primary forest (PF), 5, 10 and 30-yr old logged forest (LF-5, LF-10, LF- 30). The tree species composition differ among forest types, as it was shown that the mean value of similarity indices for all pairs were 0.215 (for the Jaccard index) and 0.353 (for the Sorensen index). The low values for similarities among forest types were most probably caused by low numbers of species shared between each forest type. Both correlation values, r = 0.023 for Jaccard index and r = 0.031 for Sorensen index, showed no strong correlation between the similarity index (C) and the distance between forest types. This supports the use of a chronosequence approach. A total of 914 tree species with ³ 10 cm dbh were recorded from 223 genera and 65 families. There were no significant differences in mean species numbers (166 – 180/ha) among treatments. Mean density of species was lower in LF-5 and LF-10 (501/ha) than in PF or LF-30 (605/ha and 577/ha); similarly to mean basal area (LF-5, 28.5 m2/ha; LF-10, 32.6 m2/ha) vs. PF (45.8 m2/ha) and LF-30 (46.9 m2/ha). Dead wood on the forest floor was significantly higher in LF-10 (75 m3/ha) than in the other treatments. Seedlings (< 2 cm dbh) of 1,022 species were recorded from 408 genera and 111 families. The mean number of tree seedling species ranged between 170-206; the mean density of seedlings was about two-fold lower in LF-10 (2790/ha) than in the other treatments. Saplings (>2 – 9.9 cm dbh) of 802 species belonged to 241 genera and 65 families. There was a high variability in species richness across treatments (89 – 191/ha), but not in stem numbers. The Dipterocarpaceae family was dominant in all treatments, followed by the Euphorbiaceae. The soils were acidic, low in nutrients and had low to very low fertility. Both primary and logged forest areas are marginal or not suitable for sustained production of plantation crops. Logging caused soil compaction in LF-30. Although in terms of number of species and trees, amount of BA, number of saplings and seedlings LF-30 appeared to have satisfied prescriptions for a second harvest, ecologically the forest is far from mature. The Indonesian Selective Cutting and Replanting (TPTI) system may need to be revised to a 35 – 45 year cycle to ensure long-term forest productivity in terms of not only timber but other goods and ecosystem services, the value of which are never quantified in monetary terms, but can be higher than the timber revenue.

Orientador: Ricardo Jannini Sawaya
Banca: Marcio Roberto Costa Martins
Banca: Laura Rodrigues Vieira de Alencar
Banca: Fernando Rodrigues da Silva
Banca: Cristiano de Campos Nogueira
Resumo: A Mata Atlântica da América do sul é um mosaico de diferentes fitofisionomias, relacionadas a pressões seletivas correspondentes a fatores ecológicos e evolutivos distintos, os quais regulam a distribuição da biodiversidade entre os habitats. Exploramos, neste trabalho, como a diversidade de serpentes é distribuída ao longo do gradiente latitudinal da Mata Atlântica. Primeiro analisamos a associação entre a riqueza em espécies e a diversidade filogenética de serpentes com tempo para especiação e extensão geográfica ao longo do gradiente latitudinal. Nós também exploramos as amplitudes de nicho climático destas serpentes. E, finalmente, decompusemos a composição filogenética de ilhas costeiras do sudeste da Mata Atlântica no intuito de entender como área e distância com o continente poderia afetar diferentes componentes da diversidade de serpentes. Encontramos que área é o principal fator relacionado com riqueza em espécies, independentemente do tempo para especiação. Observamos a maior riqueza em espécies em linhagens mais recentes nas zonas serranas do sudeste. Amplitudes de nicho climático, associadas à precipitação, mostraram conservação filogenética, afetando a distribuição dos clados mais recentes. Em nosso exemplo de ilhas, mostramos que distintos fatores ecológicos podem afetar riqueza em espécies e diversidade filogenética diferentemente. Desta maneira, fatores idiossincráticos poderiam gerar diferentes respostas em diferentes linhagens ao longo do gradiente...
Abstract: The Atlantic Forest of South America is a mosaic of different vegetation physiognomies corresponding to distinct evolutionary and ecological factors that drive biodiversity distribution. One of these factors is climatic variation. We explored herein how snake diversity, (measured as species richness and phylogenetic diversity) is distributed along the Atlantic Forest latitudinal gradient, taking area and time-for-speciation into account. We first analyzed the association of species richness and phylogenetic diversity with time-forspeciation and geographical extent along the latitudinal gradient. We also explored climatic niche breadths. And finally, we decomposed the phylogenetic composition across coastal islands in southeastern Atlantic Forest, to understand how island area and distance from the mainland drive different components of snake diversity. We found that area is a major driver of species richness, regardless of time-for-speciation. We observed higher species richness of more recent lineages in southeastern mountain ranges. Climatic niche breadths associated to precipitation showed phylogenetic conservatism, affecting the distribution of more recent clades. In our island case study, we show that distinct ecological factors can drive species richness and phylogenetic diversity differently. In this way, idiosyncratic factors generate different responses in different lineages across environmental gradients. We hope to shed some light on ecological and historical ...
Doutor

Swedish forests are mostly used for timber harvesting and 96 % of this harvesting is made by clear cutting while only 4 % is effected through other methods such as single tree harvesting. All species are not affected by forestry to same magnitude. Some specifically generalists are not affected at all. Hence, this study, had its aim to find out vascular plant species that persist, disappear or colonize other species as a result of anthropogenic disturbances in different production forests, so as to determine not only if canopy openness affects the species distribution but also the magnitude of the effects. I examined 10 different forest localities during May and June 2008. Three of these localities were made up of clear cut forest plots, 3 with partially cut down forest plots and 4 with undisturbed production forest plots. Species composition and diversity were then compared between these plots. A total of 34 different species were found. Statistical Analysis was made on how well the species in the partially cut down forest plots fitted into the undisturbed forest group as well as comparing this results with results of how counterpart species in the clear cut forest plots fitted into the undisturbed forest groups. These results showed that there was no significant difference, ANOVA values of P = 0.839, 0.602 and 0.564 respectively among the species composition between the forest, partially cut down and clear cut forest groups between the forest, partially cut down and clear cut forest plots. However, among the 54 species found in all study plots, 11 were common between the forest and partially logged sites whereas only Carex sp in the clear cut forest was common to those in the forest plots implying that canopy openness did not affect the total species number but had an effect in species composition. Clear cutting seems to kill off everything but trees and generalists. Hence, resiliency of vegetation should be increased by management practices that ensure the maintenance of prior species.

The Effects of Tropical Forest Management on Biodiversity and Ecosystem Functioning Eleanor M. Slade 1. Between 35 % and 50 % of all closed-canopy tropical forest has been lost, and the rate of deforestation continues to increase throughout the tropics. Despite a wealth of literature on the effects of tropical forest disturbance on the diversity and composition of a variety of taxa, there is still no clear consensus on the value of disturbed forests for biodiversity. 2. If forest management practises are to be sustainable in the long-term they should maintain both biodiversity and ecosystem functioning (the interactions and processes of the ecosystem), as well as a timber harvest. However, few studies have investigated the extent to which ecosystem functioning is reduced in logged forests. The effects of different logging intensities on a variety of taxa, and the ecosystem processes with which they are associated, were assessed in the Danum Valley Conservation Area in Sabah (Malaysian Borneo). 3. Even under high logging intensities, the forests of Sabah appear to have been managed in a way that maintains timber yields in the short-term. However, other aspects of forest structure had been affected, which could have important consequences ecologically, and for the long-term sustainability of timber harvests. 4. Combining field studies with manipulative experiments allows assessment of the impacts of species changes associated with habitat modification on measures of ecosystem functioning. Dung beetle (Coleoptera: Scarabaeidae: Scarabaeinae) functional group richness and composition were manipulated in a series of field experiments. Certain functional groups and species were found to have a greater impact on ecosystem functioning than others; nevertheless a full complement of species was needed to maintain full ecosystem functioning. 5. Dung beetles appeared to be relatively robust to changes in forest structure associated with selective logging, but species richness was reduced with high-intensity logging. There was a corresponding decrease in ecosystem functioning (dung and seed removal) with a decrease in species richness, and a decrease in the biomass of large nocturnal tunnellers, suggesting that although some species are dominant, rare species are also needed to preserve full ecosystem functioning. 6. A complex interaction between birds and ants resulted in reduced herbivory of seedlings of the important timber tree, Parashorea malaanonan, in some instances. However, this interaction was not affected by either selective or high intensity logging. Seedfall of P. malaanonan, was reduced in logged forest compared to primary forest. Despite insect seed predation being higher in primary forest, there was still successful recruitment during a non-mast year. Parasitism of insect-predated seeds was found to be inversely density dependent, and was higher in logged forest where seed predation was lower. 7. The results of this thesis suggest that the forests of Sabah appear to be being logged under a management system that is compatible with sustainable timber management, but not necessarily sustainable forest management. Low intensity selective logging seems to preserve much of the original forest structure, biodiversity and ecosystem functioning compared to logging at higher intensities. However, ecosystem processes were variable in their response to logging, suggesting that management decisions should be based on the consideration of multiple taxa and processes.

As the past century’s technological development has progressed the Swedish boreal forests have transformed into dense, highly productive, homogenous and coniferous forests. The area around Saxdalen in Ludvika municipality has long been dominated forests which have been heavily worked since the 18th century. There are in Ludvika 119 000 hectares of productive forest land. Around 70 percent are owned by forest companies and 20 by private forest owners. The forestry is governed by national laws and instructions from the Swedish Forest Agency. Foresters may also choose to abide by certification systems such as FSC and PEFC. 80 percent of Swedish productive forest is certified. This thesis is based on literature review and 8 field studies of regeneration fellings in Saxdalen. The purpose of this thesis is to understand to what degree environmental considerations are taken during regeneration fellings to preserve biodiversity. The focus of the thesis has been the preservation of storm sturdy trees, deciduous trees and standing dread trees, larger tree stumps and protected zones around watercourses. The protected zones were found severely lacking in practically all the observed fellings. The quality the trees preserved varied greatly between the fellings. In this study there were no found links between the ownership form or certification system and the considerations taken during regeneration fellings. A lot of parties are involved in fellings and those responsible aren’t always in full control. The work of preserving boreal forests resilience and biodiversity must be conducted in more strategic and coordinated fashion. There must be common criteria and strategies for large forest areas so that species can spread and survive the forestry, especially considering future climate change.

Det svenska kulturlandskapet har förändrats radikalt under de senaste 200 åren från ett varierat och heterogent landskap till ett mer monotont, homogeniserat landskap som följd av att olika former av mänskligt resursutnyttjande har effektiviserats. Detta har lett till en fragmentering av livsmiljöerna för flera av kulturlandskapets arter. Kraftledningsgator kan tänkas hysa naturtyper som påminner om vissa av de nu försvunna eller fragmenterade livsmiljöerna (t ex betad skogsmark och vissa typer av ängsmarker) och skulle kunna ha en viktig betydelse som reträttplats och/eller spridningskorridor för dessa arter.

I en fallfällsinventering i Köpings och Strängnäs kommun i Mälardalen undersöktes förekomst och abundans av marklevande evertebrater i kraftledningsgator, skog och betesmark. Jämförelser i förekomst och abundans gjordes mellan dessa marktyper (d v s kraftledningsgator, skog och betesmark), samt mellan positioner inom kraftledningsgator (centrala och distala delar) och närliggande skogsmark. Jämförelserna innefattade dels analyser av artantal (eller snarare antal taxa) och flera olika biodiversitetsindex och dels analyser av likhet i artförekomst och individantal med "likhetsindex" (similarity index). Separata analyser gjordes inom olika taxonomiska grupper (t ex alla taxa, endast inom insekter, endast inom spindeldjur). Antalet replikat tillät statistisk testning av eventuella mönster i antal taxa och biodiversitetsindex.

Inga signifikanta skillnader dokumenterades, varken mellan de olika marktyperna eller mellan positioner inom kraftledningsgator och närliggande skog. Vi tolkar dessa resultat som att kraftledningsgator med avseende på antal taxa respektive biodiversitet inte är (signifikant) sämre än skogs- eller betesmark. Det kan betonas att det inte heller fanns något konsekvent (icke-signifikant) mönster som pekade på att så skulle vara fallet. Antal taxa och biodiversitetsindex tar ingen hänsyn till vilka arter eller taxa som ingår i analyserna. En naturtyp som hyser en individ- och artrik fauna bestående av oönskade arter (introducerade arter, "skadedjur" etc.) registrerar t ex ett högre biodiversitetsindex än en naturtyp med fåtaligt förekommande rödlistade, skyddsvärda arter. Likhetsindex belyser bättre vilka arter som är inblandade. Visserligen tas inte heller här hänsyn till exakt vilka arter som ingår (eller deras eventuella önskvärdhet eller skyddsvärde), men ett högt index indikerar att samma arter förekommer i de jämförda naturtyperna. I denna studie indikerar ett högt likhetsindex dessutom att antalet individer av de inblandade arterna är likartat, eftersom ett index som tar hänsyn till abundans användes.

Resultaten visade överlag höga likhetsindex, speciellt verkade kraftledningsgator och skogsmark hysa likartad evertebratfauna medan likheten mellan kraftledningsgator och betesmark var mindre uttalad. Sammanfattningsvis indikerar studien att kraftledningsgator inte verkar vara lågvärdiga livsmiljöer för de marklevande evertebrat-taxa som ingått i studien. Vi föreslår att kraftledningsgator med väl avvägda rutiner för röjning och skötsel skulle kunna spela en viktig roll i skapandet av artrika kantzoner eller marker som liknar ängs- eller betesmarker med svag hävd.

As a consequence of the intensification of various forms of human resource utilization rural Sweden has changed radically over the past 200 years from offering a varied and diverse landscape to a more monotonous, homogenised type of environment. This has led to fragmentation of habitats for many of the species occurring. Power line corridors might harbour habitats that resemble some of the now lost or fragmented habitats (e.g. grazed forest land and certain types of meadow), and could have important functions as refuge habitats and / or distribution corridors for these species.

In a pitfall trap study in Köping and Strängnäs municipalities in Mälardalen, the occurrence and abundance of ground-living invertebrates were investigated in power line corridors, adjoining forest and pastures. Comparisons were made between these habitat types, and between positions within the power line corridor (central and distal parts) and the nearby forested area. The comparisons included analysis of number of species (or rather the number of taxa) and several biodiversity indexes, as well as analysis of the similarity of the occurrence of certain species and individual numbers by use of "similarity index". Separate tests were made in different taxonomic groups (e.g. all taxa, only within insects, only within spiders). The number of replicates allowed statistical testing of patterns in the number of taxa and biodiversity index.

No significant differences were documented, neither between the different habitat types, nor between positions in the power line corridors and nearby forest. There was also no consistent (non-significant) pattern indicating that this would be the case. We suggest these results to indicate that power line corridors at least are not (significantly) poorer quality habitats than are forest or pasture land with regard to number of taxa and biodiversity. Number of taxa and biodiversity indices take no account of the species or taxa included in the analysis. Thus the same weight is assigned to an unwanted species (e.g. an invasive pest species or parasite) as to a red-listed, highly valued species. Similarity index takes more heed to the species involved. Although similarity indices do not consider the exact identity of involved species (or their possible value or desirability), a high index value indicates that the same species occur in the compared habitats. In this study, where an index that takes into account the abundance of species was used, a high similarity index value also indicates that the numbers of individuals are similar.

Overall, the results showed high similarity between habitat types. This would suggest that, to a large extent, power lines, forest and pasture land had the same composition of taxa, and that the taxa had similar abundances. Power lines and forest seemed to exhibit particularly high similarities, whereas the similarity between power lines and pasture land was less pronounced. Thus, this study indicates, in contrast to several previous suggestions, that power line corridors do not seem to be low quality habitats. We also suggest that power line corridors with well designed management routines could play an important role creating edges and habitats resembling meadow or low intensity grazed pasture land.

South American temperate forests are globally exceptional for their high concentration of endemic species. These ecosystems are one of the most endangered biomes on Earth because nearly 60% of forests have been lost. Current knowledge of most Neotropical forest owls is limited. I examined (i) detectability, (ii) occurrence and habitat-resource utilization across spatial scales, and (iii) surrogacy reliability of the threatened habitat-specialist rufous-legged owls (Strix rufipes) and habitat-generalist austral pygmy-owls (Glaucidium nana) in southern Chile. During 2011-2013, I conducted 1,145 owl broadcast surveys, and established 505 vegetation plots and 505 avian point-transects across 101 sites comprising a range of conditions from highly degraded habitat to structurally complex old-growth forest stands. I recorded 292 detections of S. rufipes and 334 detections of G. nana. Detectability for both owls increased with greater moonlight and decreased with environmental noise, and for G. nana greater wind speed decreased detectability. Detection of either species was positively correlated with the detection of the other species. For S. rufipes, occurrence probability ranged from 0.05-1 across sites, and was positively associated with bamboo density and the variability in diameter at breast height of trees (multi-aged forests). For G. nana, occurrence ranged from 0.67-0.98, but the parameter estimates for covariates overlapped zero, meaning they occurred across the full range of habitat conditions. Relative to G. nana, S. rufipes had lower total resource utilization, but achieved similar peak occurrence for resources related to stand-level forest complexity and forest homogeneity at the landscape scale. I found that S. rufipes were reliable surrogates for avian species richness, endemism and measures of functional biodiversity (e.g. large-tree users, understorey users, degree of community specialization). Strix rufipes and specialist avian species and guilds aggregated at the relatively stable, least degraded, sites. This “specialist aggregation” was driven by forest-stand structural complexity. Forest management practices that maintain multi-aged stands with large trees and high bamboo cover will benefit both owls, and will be linked to a higher density of vulnerable endemic species, specialized wildlife communities and, likely, ecosystem stability in temperate forests.
Forestry, Faculty of
Graduate

Expanding anthropogenic development within the tropical forest biome is driving the loss of an irreplaceable global resource. Mega-diverse tropical forests are vital for regulating the global carbon cycle, and are essential for climate change mitigation. Today, over half of the world’s remaining tropical forest is degraded or regenerating secondary forest. Tropical forests are becoming increasingly fragmented through the expansion of agriculture and roads. Landscape-scale flooding of terrestrial habitats caused by dam construction is an emerging driver of habitat loss and fragmentation. Much attention has been paid to the long-term impacts of tropical forest fragmentation for biodiversity, ecosystem functioning, and carbon emissions. Most of our understanding of the impacts associated with habitat fragmentation originates from systems in which the habitat matrix surrounding remnant forest patches is another, albeit low quality, terrestrial habitat. However, dam-induced habitat fragmentation results in remnant terrestrial biological communities becoming isolated on islands within a water matrix. A water matrix presents the worst-case scenario for remnant habitat fragments. In Chapter 2 I synthesise the results of numerous studies reporting the responses of taxonomic groups to isolation on reservoir land-bridge islands, and uncover a globally-applicable pattern of extinction debt acting upon remnant biological communities on reservoir islands. All islands, regardless of taxonomic group, habitat type, or island area lose species as island isolation time increases. Moreover, I show that contrary to existing ecological theory, once terrestrial habitat becomes isolated within a water matrix, it is effectively too isolated for species losses to be buffered by metapopulation dynamics. Dam development is rapidly expanding in the largest remaining tract of intact tropical forest, the Amazon Basin. In Chapters 3 and 4 I study the Balbina mega-dam system in the central Brazilian Amazon. Here, I use detailed field inventories of trees and lianas on islands and in continuous mainland habitat to determine the impact of landscape-scale habitat fragmentation caused by reservoir creation on these taxonomic groups. I find that islands maintain tree communities at significantly lower densities, richness and diversity compared to continuous forest. Furthermore, tree communities on islands exhibit compositional divergence from those found in mainland continuous forest. Island tree assemblages are dominated by low-wood density species, and may be on a trajectory towards communities characteristic of early successional forests with reduced carbon storage capacity. In contrast, liana assemblages remain compositionally intact and are becoming increasingly dominant relative to trees. Thus, lianas appear robust to many of the negative impacts associated with landscape-scale habitat fragmentation. As insular tree communities continue to degrade through area- and edge-effects, lianas may become a key feature of this archipelagic landscape due to their competitive advantage over trees in disturbed forest habitats. Lianas significantly inhibit tree recruitment and carbon storage. Thus, findings from Chapters 3 and 4 provide strong evidence for additional, and currently unaccounted-for biodiversity and carbon impacts associated with tropical dams. As development of tropical forest regions increases, there is an urgent need to reconcile the need for resources with the need for ecosystem service provision, such as carbon storage, particularly as we attempt to mitigate the impacts of rising atmospheric carbon. Recent studies have shown that secondary tropical forests have the potential to rapidly uptake atmospheric carbon, and act as a powerful tool in climate change mitigation policy. Broad-scale estimates of secondary forest carbon uptake are currently based on above-ground biomass alone. In Chapter 5 I present carbon stock estimates of additional tropical forest carbon pools - soil and dead woody biomass - in secondary forests ranging from 40-120 years. I find that soil fertility (nitrogen concentration) is key in determining carbon storage in secondary forests, and that the stability of carbon stocks held in dead woody biomass increases with secondary forest stand age. I highlight the need to integrate detailed site-specific information into broad-scale predictive models of secondary tropical forest carbon sequestration. This thesis links ecological theory and landscape-scale field inventories, to provide new understanding of the long-term costs of tropical forest fragmentation for biodiversity conservation and carbon storage, and provides further evidence of the important role secondary tropical forests may play in carbon sequestration and climate change mitigation.

Mangrove forests provide a significant contribution to human well-being; particularly through climate change mitigation and adaptation (CCMA) due to disproportionately high carbon sequestration and coastal protection from tropical storms. However, mangrove community structure drivers of these ecosystem services (ES), rehabilitation potential for high CCMA ES delivery, and their resilience to climate change impacts remain poorly understood and monitored. This thesis uses field- and satellite remote sensing-based methods and a dual focus at a Philippines-specific and West Africa to South Asian-scale to quantitatively assess mangrove CCMA ES delivery. The first three chapters provide a background, and literature review on ES delivery, ecological restoration and resilience to perturbations, mangrove ES, their anthropogenic and climate change threats, and current management. Chapters 4 and 5 detail the case study selection and methodologies employed. Chapter 6 focuses on the flora community structure drivers of mangrove ES delivery, and shows that divergent controls can drive trade-offs in the delivery of key CCMA benefits. Chapter 7 focuses on the potential of mangrove rehabilitation for high CCMA ES delivery, and shows that mangrove rehabilitation in abandoned aquaculture ponds can provide high relative CCMA benefits, revealing large areas of abandoned aquaculture with favourable tenure status for greenbelt rehabilitation. Chapter 8 focuses on remote monitoring of mangrove resilience to sea level rise, and the potential anthropogenic and abiotic factors influencing these, establishing a methodology for continued remote monitoring and revealing variability in resilience and resistance across forests. Overall, it is demonstrated that current mangrove management in the Philippines and globally may be insufficient to secure high CCMA ES delivery, due to (1) non- consideration of flora community structure, site-specific and areal requirements, (2) complexity in governance systems for reclamation of mangrove lands, and (3) a lack of spatial planning and zoning to accommodate mangrove resilience to climate-induced perturbations.

Biological communities are changing across the globe as a result of anthropogenic pressures; abundances of individuals are declining within populations and species are becoming extinct. Biological diversity and trophic complexity in grasslands and soil food webs are positively associated with the cycling of nutrients in soil and water, primary productivity and decomposition. Since these ecosystem processes underpin a number of goods and services to society, human-driven changes in the structure of ecosystems could negatively impact upon human wellbeing. However, the majority of our knowledge of the role of biodiversity in ecosystem functioning comes from studies conducted in temperate grassland systems. Consequently, our understanding of how of higher-level organisms influence ecological processes in different ecosystems is limited. This thesis aims to address these knowledge gaps by investigating how dung beetle traits and functional diversity influence the secondary dispersal of seeds and the emergence and survival of seedlings in the northeastern Brazilian Amazon. My first research aim was to understand the importance of intraspecific variability in dung beetle traits for the accuracy of functional diversity (FD) indices (Chapter 2). This chapter demonstrates that intraspecific differences in dung beetle traits are small compared to between species differences. However, failure to include intraspecific variability resulted in large errors in the calculation of FD indices when describing small and/or species poor communities. Second, I investigated how dung beetle diversity influences secondary seed dispersal, and the role of environmental context in modulating relationships. Here I reveal positive relationships between dung beetle functional diversity and both the probability of seed burial and the dispersion of seeds throughout the soil profile. However, these patterns were dependant on soil type and thus environmental context (Chapter 3). Finally, I explored the multitrophic significance of findings from Chapter 3 by testing how dung beetle communities affect the burial of different sizes of seeds and emergence and survival of seedlings (Chapter 4). Results from this chapter demonstrate how dung beetles could influence vegetation regeneration because beetle diversity negatively affected the likelihood that experimental seeds emerged from the soil surface, but positively impacted on the likelihood that emerged seeds survived until the end of the experiment period. Furthermore, I show that large seeds could be more vulnerable to anthropogenic driven changes in dung beetle communities than smaller seeds. These research aims were realised through field-based experiments from which I sampled and identified approximately 2,650 dung beetles from 180 naturally formed communities, collected more than 17,000 morphological trait measurements and sieved approximately 11 tonnes of soil in search of 1800 seed mimics. Overall, this work demonstrates diversity in dung beetle communities is positively associated with the ecological processes they govern but that environmental context is instrumental in modulating biodiversity-ecosystem functioning relationships. I use the outcomes from this work to discuss the challenges in describing diversity-functioning relationships across trophic levels. Finally, I highlight that ecological processes are the product of complex species-specific interactions, dependent on the biotic and abiotic environment. Therefore, predicting the consequences of anthropogenic-driven species losses for the structure and functioning of natural systems is a major research challenge.

Species’ ranges are configured according to their tolerance of environmental conditions, especially climate, and their history of dispersal since speciation. Previous studies of the potential impact of climate change on biodiversity have been biased towards species of high latitudes. This situation results from a lack of detailed knowledge about the distribution of tropical biodiversity, and from the smaller degree of warming expected at low latitudes. However, various General Circulation Models (GCMs) simulate regional drying and increasing seasonality for parts of the tropics, including Amazonia. This may have a greater impact on tropical forest flora than temperature change alone. The Amazon region holds a high proportion of global biodiversity, yet conservation plans rarely consider possible climate change impacts. This thesis presents a methodology for projecting a set of Amazonian plant species’ ranges from limited data, and estimating their response to climate change scenarios. Species are classified into plant functional types (PFTs), which share traits such as growth form and reproductive strategy. Species' current distributions are modelled over a coarse scale (a 1º latitude-longitude grid), using a suitability index based on bioclimate variables. Distributions are additionally limited by species’ absolute tolerances to extreme values, and by dispersal barriers. A sizestructured population is simulated for each cell, to enable modelling of lags in response to climate change. In the standard impact scenario (SIS), future population processes are simulated over 100 years, with changes in the variables governing cell suitability being applied annually according to anomalies from a selected GCM. The run is repeated for each species using anomalies of half that magnitude, as a reduced-impact scenario (RIS). The range of potential outcomes for each species and PFT is evaluated. Widespread impacts are seen under both scenarios. An alternative impact scenario (AIS) is devised to examine the effects of allowing some "c-species" to thrive under heightened AET. The most vulnerable taxonomic groups, PFTs and geographical regions are identified as targets for monitoring and conservation action. In particular, there is a dramatic loss of species' viability in much of northeastern Amazonia at 2095 under all scenarios. The far western part of Amazonia is identified as important for persistence of the greatest number of species. Areas falling between the major rivers of the region have very limited distribution data, so are highlighted for future biodiversity survey work.

La presente tesi è stata ideata come contributo al crescente bisogno di avere solide basi scientifiche e strumenti efficaci per la comprensione, il monitoraggio e la gestione del paesaggio mirati alla conservazione della sua biodiversità. I concetti, le teorie, le metodologie e le ipotesi testate nel presente lavoro, poggiano le loro basi scientifiche nella disciplina dell'Ecologia del Paesaggio (Landscape Ecology). L'Ecologia del Paesaggio è una branca relativamente moderna dell'ecologia, che ha come obiettivo lo studio delle interazioni che intercorrono tra il pattern spaziale ed i processi ecologici in un mosaico territoriale. In particolare, la presenti tesi ha voluto approfondire alcuni aspetti chiave dell’Ecologia del Paesaggio e si è proposta di fornire un doppio contributo: uno nell'ambito delle metodologie per l'analisi multi-temporale e multi-scalare del paesaggio e l'altro nell'ambito dell'applicazione dell'Ecologia del Paesaggio alla conservazione e la gestione della biodiversità. Il presente lavoro di tesi è stato organizzato in tre sezioni a loro volta articolate in capitoli. La prima sezione è stata pensata per dare risposta alla seguente domanda: (I) When Are Two Landscapes Significantly Different? Applications in Temperate Forest Landscapes (Capitoli 1-2). La seconda sezione è focalizzata sull’analisi della frammentazione nel tempo e presenta dei casi studio in paesaggi subtropicali: (II) Measuring Forest Fragmentation Over Time: Applications in Subtropical Forests Landscapes (Capitoli 3-5). La terza sezione è costituita da numerose applicazioni dell’ecologia del paesaggio alla conservazione della natura: (III) Applying Landscape Ecology in Biological Conservation (Capitoli 6-10). Nelle prime due sezioni sono stati proposti ed implementati nuovi approcci per quantificare ed analizzare il pattern spaziale del paesaggio. In particolare nel primo e secondo capitolo della prima sezione è stato proposto lo sviluppo di metodi in grado di (i) fornire un contesto statisticamente robusto all'interno del quale confrontare il pattern spaziale di due paesaggi diversi oppure dei loro cambiamenti nel tempo e di (ii) analizzare la dipendenza scalare del cambiamento del pattern. Per fornire un contesto statisticamente robusto all'interno del quale confrontare due paesaggi, sono necessarie delle repliche, dalle quali derivare stime, valori medi, intervalli di confidenza. Nel Capitolo 1 è stato proposto di utilizzare modelli neutrali di simulazione del paesaggio. In particolare, tali modelli, hanno permesso di simulare un set di paesaggi i cui pattern spaziali hanno proprietà statistiche in comune (composizione e configurazione) con i paesaggi reali. Una volta simulate un numero sufficiente di repliche, sulle quali calcolare i diversi indici di pattern, è stato possibile ottenere distribuzioni empiriche per ogni indice. Tali distribuzioni sono state utilizzate per confrontare due o più paesaggi e determinare se, le differenze osservate in termini di indici di paesaggio, sono significative ad un determinato livello di confidenza. Nel Capitolo 2 viene adoperato un approccio simile al fine di determinare l'esistenza di scale spaziali significative alle quali emergono determinati processi ecologici. Le metodologie sopra menzionate, sono state utilizzate per la quantificazione del pattern spaziale di paesaggi appenninici (foreste temperate). La seconda sezione ha riguardato lo studio dei cambiamenti temporali in paesaggi subtropicali. Sono stati proposti nuovi metodi per la quantificazione del fenomeno della frammentazione basati su: un approccio di tipo campionario (Capitoli 3 e 4) e un approccio multi-scala (Capitolo 5). Nello specifico, è stato proposto un metodo per lo studio della frammentazione delle foreste subtropicali che si basa sulla stima della copertura e configurazione spaziale delle foreste attraverso campionamento di cartografie derivate da immagini satellitari. Tramite tale applicazione è stato possibile ottenere una valutazione statistica sul contributo relativo della perdita delle foreste (forest loss) e del cambiamento della loro struttura spaziale (spatial pattern change) nel processo di frammentazione. Nel capitolo 5 il processo di frammentazione è stato quantificato utilizzando la "context analisi multi-scalare". Secondo questo approccio la qualità, la funzionalità e la persistenza degli elementi del paesaggio (p.es., pixel di bosco nel caso di cartografia raster, ecc.) sono fortemente condizionate dalle caratteristiche del mosaico territoriale che li circonda. In altre parole, ogni località classificata come bosco, viene definita sulla base del tipo di frammentazione che caratterizza il paesaggio circostante (p.es copertura e connettività) la quale viene descritta a scale spaziali multiple, da scale locali a regionali. Le metodologie proposte nella presente ricerca, hanno degli evidenti vantaggi ma anche delle limitazioni e, possono essere utilizzati in maniera complementare per descrivere e confrontare, in un contesto statistico robusto, numerose tipologie di paesaggio. L’utilità delle nuove metodologie è stata testata nello studio di diversi mosaici territoriali caratteristici di ecosistemi temperati e subtropicali. Le metodologie proposte potrebbero essere testate anche in altri paesaggi quali i paesaggi urbani e, in questo contesto, potrebbero aprire un interessante ambito di ricerca per studi futuri. La terza sezione è stata costruita come una raccolta di casi studio in cui, gli strumenti dell'Ecologia del Paesaggio, vengono applicati allo studio ed alla conservazione di comunità e specie particolarmente minacciate. Nel Capitolo 6 sono stati studiati gli effetti della frammentazione sulla biodiversità di flora vascolare in foreste temperate. In particolare sono state analizzate le relazioni tra il pattern spaziale (dimensione, geometria e grado di isolamento delle macchie di paesaggio) di un habitat forestale tipico dei paesaggi appenninici italiani (Faggeti degli Appennini con Taxus e Ilex – EU cod. 9210*) e le caratteristiche floristiche di tali formazioni. Nel capitolo 7, si è affrontata la problematica della conservazione di specie volatrici (chirotteri) a livello di paesaggio in relazione alla presenza di impianti eolici sul territorio. Per quanto riguarda il Capitolo 8, si è indagato sulla conservazione e la gestione degli habitat di duna costiera tenendo conto delle loro valenze sia in termini di biodiversità floristica che di fauna. Nello specifico sono stati analizzati dati derivati da cartografia digitale degli habitat d’interesse conservazionistico (Direttiva Habitat 92/437CEE) insieme a dati radiotelemetrici di Testudo hermanni come esempio di specie di fauna minacciata (EN IUCN 2014) e caratteristica di questi habitat. Nel capitolo 9, si è analizzata la riposta del paesaggio vegetale di alta quota al riscaldamento climatico globale. In particolare, sono state studiate la trasformazioni della vegetazione sommitale avvenute durante gli ultimi 10 anni sulle vette italiane (Appennino centrale e Alpi Sudorientali - rete Long Term Ecological Research). Infine, nel capitolo 10 è stata proposta e testata una procedura per la cartografia dell’età dei boschi in base a immagini telerilevate e modelli alsometrici. Nel presente lavoro di dottorato, sono state affrontate numerose problematiche relative all’analisi delle trasformazioni del pattern spaziale nel tempo e alla conservazione della biodiversità di differenti habitat e specie particolarmente minacciate da fattori ambientali ed antropici. Le informazioni e le metodologie fornite dalla presente tesi offrono strumenti adeguati per definire misure di conservazione e piani di gestione capaci di migliorare il destino degli habitat naturali e semi-naturali e delle specie che ospitano.
This thesis was conceived as a contribution to the increasingly urgent need to have sound scientific basis and effective tools to understand, monitor and manage the landscape in order to preserve the biological diversity that characterize landscapes. In this work, concepts, theories, methodologies and tested hypothesis, are proper of Landscape Ecology. Landscape Ecology is a young branch of modern ecology that deals with interrelationship between the spatial pattern and ecological processes in a given land mosaic. In particular, this thesis work offers a double contribution: First, it provides new methodologies for the multi-temporal and multi-scale analysis of the landscape and its changes and; second, it applies Landscape Ecology theories and methods to the conservation and the management of landscape biodiversity issues. The thesis work is organized into three sections, which are in turn subdivided into different chapters. The first section attempts to answer the following question: (1) When Are Two Landscapes Significantly Different? Applications in Temperate Forest Landscapes (Chapters 1, 2). The second section focuses on the analysis of forest fragmentation over time in subtropical forests landscapes: Measuring Forest Fragmentation Over Time: Applications Subtropical Forest Landscapes (Chapters 3-5). Finally, the third section deals with some implementations of Landscape Ecology in biological conservation: Applying Landscape Ecology in Biological Conservation (Chapters 6-10). The first section of the thesis focuses on the development of new methods in order to (i) provide the statistical significance of the observed differences when comparing different landscapes or their changes over time and (ii) analyze the scale dependence of the spatial pattern change. To properly handle the first issue, a new method to test the statistical significance of pattern metric values between two maps was proposed. In particular, the method was based on the use of Neutral Landscape Models (NLMs) able to reproduce a set of real-like (in terms of composition and configuration) simulated landscapes. For each simulated landscape, pattern metrics can be computed and can used to produce null empirical distributions for each metric. These empirical distributions can be used to determine if, the observed differences in terms of pattern metrics are significant for a given confidence interval. The second goal was achieved by extending the NLMs approach into the spatial domain to analyze the scale-dependence of landscape changes. Both methods were demonstrated in temperate forest landscapes. The second section deals with the analysis of forest fragmentation in subtropical ecosystems. Also in this case new methods to quantify the spatial pattern of forests over time were proposed. First, the analysis of the spatial pattern change by means of sample-based techniques. By randomly sampling forest cover multi-temporal maps it was possible to statistically quantify and distinguish changes in forest cover from changes in the spatial pattern of forest. Second, the process of forest fragmentation was studied according to the “landscape context analysis” that is, each forest location was described by its context, using indices derived from the landscape that surrounds it, across a range of scales (from local to regional). These methods each have their own set of advantages and limitations, and yet may work in a complementary manner. Moreover, in this work the usefulness of the proposed techniques was demonstrated in different environments such as temperate and subtropical forests. However, they can be easily extended to other landscapes such as urban landscapes and, in this respect, they could be an interesting field of further researches. The third section presents a series of study cases where landscape ecology was applied to biodiversity conservation. In particular, five works were presented: the first deals with the relationship between landscape structure and biodiversity in temperate forest landscapes. The second focuses on the impact of windfarms on the foraging habitat of two bat species at landscape level. The third was aimed to the study of the habitat selection by terrestrial tortoise in high conservation value protected areas. The fourth work analyzes short-term variations of high vegetation summit to the global warming. Finally, the fifth study case deals with the spatial estimation of forest age structure on the basis of remote sensing images and yield models. All the presented contributions deal with landscape ecology. Landscape change is known as one of the most important driver of the biodiversity crisis worldwide. In this respect, the present thesis attempted to give an important contribution to the quantification of the landscape spatial pattern and thus to the relationship between spatial pattern and ecological processes (e.g., fragmentation, habitat selection, etc.). Moreover, these findings potentially addressed the urgent need to have useful tools in order to define conservation measures and management plans, which are essential for the protection of natural and semi-natural habitats and their threatened species in a changing world.

Depuis les années 1980, de nombreuses études ont montré l’importance des peuplements forestiers très matures et de leurs attributs constitutifs (arbres de gros diamètre, bois morts…) pour la conservation de la biodiversité forestière. Ces travaux ont permis d’initier un processus en faveur d’une meilleure reconnaissance de la fonction écologique des forêts. La plupart de ces études ne tiennent cependant pas compte de la notion d’ancienneté des forêts, i.e. de la continuité temporelle de l’état boisé. Cette notion apparaît pourtant pertinente pour expliquer la répartition de certaines espèces. Ainsi, une forêt ancienne, même rajeunie par une perturbation, pourrait jouer un rôle pour la conservation de la biodiversité tout aussi important qu’une forêt récente constituée de peuplements très matures. Cette relation a priori contrastée entre biodiversité et maturité d’une part et biodiversité et ancienneté d’autre part, soulève de nombreuses questions quant aux choix stratégiques à mettre en place pour une conservation et une gestion optimale de la biodiversité en forêts. Plus généralement, ces notions permettent de questionner l’influence relative des activités humaines passées et actuelles sur la biodiversité forestière. Afin de préciser les effets relatifs de l’ancienneté et de la maturité sur la biodiversité, une approche combinant géohistoire et sciences de l’environnement a été mise en place. Un dispositif d’étude de 70 sites, croisant des forêts anciennes ou récentes avec des peuplements peu matures ou très matures, a été développé dans les Préalpes francçaises (Vercors, Chartreuse et Bauges). Pour chacun des sites, l’ancienneté et la maturité ont été caractérisées et quatre groupes taxinomiques ont été inventoriés : flore vasculaire, coléoptères saproxyliques, collemboles et macrolichens épiphytes. Nos résultats indiquent une absence flagrante d’effet d’héritage dû aux usages passés, à la fois dans les sols et sur la biodiversité. Les espèces étaient avant tout influencées par la maturité des peuplements, notamment la diversité des bois morts pour les coléoptères saproxyliques et l’ouverture de la canopée pour la flore vasculaire. Le sol, à travers le pH et les formes d’humus, avait également un rôle structurant fort sur la flore vasculaire et les collemboles, et le climat, à travers les températures, sur les coléoptères saproxyliques. Cet effet limité de l’ancienneté, comparativement aux études antérieures, est à mettre en relation avec le contexte écologique, paysager et historique des forêts de montagne : fort taux de boisement, forte proportion de forêts anciennes, surfaces boisées peu fragmentées, usage ancien peu impactant et gestion forestière actuelle assez extensive. Nos résultats montrent ainsi que l’effet des usages anciens sur la biodiversité dépend fortement du contexte. Ils soulignent l’importance de la prise en compte des conditions environnementales locales, attributs de maturité mais aussi conditions climatiques et édaphiques, pour une compréhension plus fine des patrons de biodiversité en forêts de montagne
Since the 1980s, numerous studies had shown the importance of stand maturity, especially old-growth habitat features (very large trees, deadwood…) for forest biodiversity conservation. This work led to a better recognition of the ecological function of forests. However, most of these studies do not take account of forest continuity, i.e. the temporal continuity in forested condition. Forest continuity has been used to explain some species distribution. Therefore, ancient forests, even rejuvenated by disturbances, may be of greater conservation interest for biodiversity than recent forests composed of overmature stands. This a priori contrasting relationship between biodiversity and stand maturity on the one hand and biodiversity and forest continuity on the other hand, raises many questions about the most appropriate policy choices to conserve and manage adequately forest biodiversity. More generally, these concepts allow the questioning of the relative influence of past and present human-induced environmental changes on forest biodiversity. To clarify the relative effects of forest continuity and stand maturity on biodiversity, we developed an approach in which we combined historical ecology and environmental sciences. We established 70 sites in the French Prealps (Vercors, Chartreuse and Bauges) in which we crossed ancient or recent forests with mature or overmature stands. For each site we characterized forest continuity and stand maturity and assessed the response of four taxonomic groups: vascular plants, saproxylic beetles, springtails and epiphytic macrolichens. Results showed an obvious lack of legacy effect on both soil conditions and biodiversity. Species were above all influenced by stand maturity, especially deadwood diversity for saproxylic beetles and canopy openness for vascular plants. Soil conditions, through pH and humus forms, had also a great structuring role on vascular plants and springtails, and climatic conditions, through temperature, on saproxylic beetles. Comparatively to previous studies, this quite limited effect of forest continuity can be linked with the ecological, landscape and historical context of mountain forests: high percentage of forest cover, high proportion of ancient forests, low-fragmented wooded areas, past land use being low impacting and current extensive forest management. Overall, our results show that the effect of forest continuity on biodiversity is context dependent and underline the necessity to better account for local environmental conditions, stand maturity attributes but also climatic and edaphic conditions, to improve our understanding of biodiversity patterns in mountain forests

Globally, more than half of the world's population is living in urban areas and it is well accepted that human activities (e.g. climate warming, pollution, landscape homogenization) pose a multitude of threats to ecosystems. Largely, human-related impacts on biodiversity will hold consequences for larger ecological processes and research looking into human impacts on sensitive epiphytic lichen and moss communities is an emerging area of research. While seemingly small, lichen and moss communities exist on nearly every terrestrial ecosystem on Earth and contribute to whole-system processes (e.g. hydrology, mineral cycling, food web energetics) worldwide. To further examine human impacts on epiphytic communities, I conducted three studies examining urbanization and climate warming effects on epiphytic lichen and moss biodiversity and ecology. In the first study I revisited a historic urban lichen community study to assess how urban lichen communities have responded to regional air quality changes occurring over the last nearly two decades. I further investigated, for the first time, the biodiversity of urban tree canopy-dwelling lichen communities in a native coniferous tree species, Pseudotsuga menziesii. I found that urban parks and forested areas harbor a species rich community of lichens epiphytes. Further, I found evidence for the distinct homogenization of urban epiphytic lichen communities, suggesting that expanding beyond simplistic measures of biodiversity to consider community composition and functional biodiversity may be necessary when assessing the ecology and potential ecosystem services of epiphyte communites within urbanizing landscapes. Next, I present the first tall tree canopy study across a regional gradient of urbanization near Portland, Oregon, USA. I found that tall tree canopy epiphyte communities change dramatically along gradients of increasing urbanization, most notably by the transitioning of species functional groups from sensitive, oligotrophic species to a dominance of urban-tolerant, eutrophic species. The implications these dramatic shifts in species composition have on essential PNW ecosystem processes, like N-fixation and canopy microclimate regulation, is still not well understood and is difficult to formally evaluate. However, I find strong evidence that native conifer trees in urban areas may provide a diversity of essential ecosystem services, including providing stratified habitat for epiphyte communities and their associated micro arthropod communities and the scavenging of atmospherically deposited nutrients. Future work is needed to understand how losses in canopy N fixation and species with large biomass (both lichens and bryophytes) will affect nutrient and hydrologic cycling in the PNW region, which continue to undergo rapid growth and urbanization. The final chapter investigates the impacts of passive warming by Open Top Chambers (OTCs) in moss-dominated ecosystems located on the Western Antarctic Peninsula, an area of increasing climate warming. I compared species-specific temperature effects, moss canopy morphology, sexual reproductive effort and invertebrate communities between OTC and control moss communities for two moss species, Polytrichastrum alpinum and Sanionia uncinata, that make up over 65% of the terrestrial vegetative cover in the area. I found distinct reproductive shifts in P. alpinum under passive warming compared to controls. Moss communities under warming also had substantially larger total invertebrate communities than those in control moss communities, and invertebrate communities were significantly affected by moss species and moss reproductive effort. Further, substantial species-specific thermal differences among contiguous patches of these dominant moss species were revealed. These results suggest that continued warming will differentially impact the reproductive output of Antarctic moss species and is likely to dramatically alter terrestrial ecosystems dynamics from the bottom up. This combined work provides a diverse contribution to the field of epiphyte ecology and biology by providing new insights on how human impacts will affect epiphyte lichen and moss communities across diverse ecosystems, in light of a rapidly changing planet.

Processes structuring bee communities in agricultural landscapes are well-documented compared to those in other anthropogenic landscapes, like production forests. Forests across the temperate zone have historically been under-sampled, in part due to the perception that they provide little habitat to support diverse bee communities. While research suggests that early successional habitats support high levels of bee species richness and abundance, little empirical evidence exists to support the notion that forests, in turn, do not. To understand the relationship between forest successional age and major elements of the bee community, I sampled bees in a southern production pine forest in Hancock County, MS across 2012 and 2013. I found that while bee abundance declines with successional age, species richness does not. Combining this work with other recent research, I propose a generalized framework for understanding the role of disturbance and forest structure in structuring bee communities of southern forests.

Gli ecosistemi attraverso il loro normale funzionamento offrono una gamma di beni e servizi importanti per il benessere umano, che sono chiamati collettivamente servizi ecosistemici (ES). Le città dipendono dagli ecosistemi e dei loro componenti per sostenere condizioni a lungo termine per la vita. La fornitura di servizi ecosistemici varia spazialmente attraverso paesaggi, determinata da diverse interazioni sociali, politiche ed ecologiche e coinvolge l'analisi dell'ambiente in una prospettiva interdisciplinare basata sull'integrazione delle dimensioni ecologiche e socio-economiche. Questo studio rappresenta una ricerca multidisciplinare che si è concentrata sull'analisi di molteplici servizi ecosistemici nell'area urbana di Milano (Italia), con particolare riguardo a quelli forniti dai parchi e dalle foreste urbane. Cinque studi specifici sono stati sviluppati al fine di analizzare i diversi servizi ecosistemici legati alla biodiversità, alla mitigazione dell'inquinamento, allo stoccaggio del C organico dei suoli urbani, e ai servizi culturali. Il primo studio ha proposto una metodologia per definire spazialmente l'estensione della regione urbana (UR) di Milano.La frammentazione del paesaggio e l'espansione urbana sono stati quantificati. I risultati hanno rivelato che la UR di Milano soffre di alto grado di frammentazione del paesaggio in tutta l'area, con i principali territori frammentati nel nord della città di Milano (Monza e Varese). L'espansione urbana ha mostrato una tendenza all'aumento negli ultimi 50 anni, raggiungendo valori allarmanti fino ad oggi. Nel secondo studio è stato studiato il ruolo delle foreste urbane nella fornitura di habitat idonei per la biodiversità. Sono state analizzate le caratteristiche ambientali del contesto urbano a diverse scale e come la struttura della vegetazione influenza la presenza di diverse specie di uccelli. Lo studio ha mostrato come i pattern di biodiversità trovati possono essere spiegati considerando gli effetti delle caratteristiche ambientali che agiscono a vari livelli e che le aree verdi urbane possono quindi essere gestite attivamente al fine di preservare la diversità biologica. Il terzo studio rappresenta un lavoro preliminare sul potenziale di degradazione di idrocarburi delle comunità microbiche epifite su Platanus x acerifolia, alberi comuni utilizzati in aree urbana. Il quarto studio stima lo stoccaggio del C organico (OC stock) dei terreni urbani dei parchi, foreste e altre tipologie di coperture del suolo urbano. OC stock medio trovato per i suoli urbani di Milano è paragonabile ai valori trovati per i terreni agricoli in Lombardia. OC stock è stato trovato più elevato per i parchi rispetto ad altre zone, ma senza una chiara differenziazione tra tipologie di area. I risultati evidenziano come la complessa eterogeneità dei suoli urbani insieme con l'incertezza delle loro origini, la loro storia e la gestione possono riassumere i limiti nella nostra capacità di modellare le loro caratteristiche. Il quinto studio ha analizzato i servizi ecosistemici culturali (CES) percepiti dai cittadini in uno dei più grandi parchi dell'area di studio (Parco Nord). Lo studio presenta una metodologia per utilizzare la mappatura CES (PPGIS) a supporto delle decisioni nella pianificazione territoriale. Un confronto con i benefici culturali percepiti da persone e quelli percepiti dalla direzione del parco ha mostrato luoghi nel parco con concentrazioni di valori diversi, e in altri luoghi con concentrazioni dello stesso tipo di valore e presenza di hotspot e coldspot di CES in termini di ricchezza.
Ecosystems, through their normal functioning, provide a range of goods and services important for human well-being, which are collectively called ecosystem services (ES). Cities depend on ecosystems and their components to sustain long-term conditions for life. The provision of ecosystem services varies spatially across landscapes, determined by diverse human social, political and ecological interactions and it involves the analysis of the environment in an interdisciplinary perspective based on the integration of ecological and socio-economic dimensions. This study represented a multi-disciplinary research that focused on the analysis of multiple ecosystem services in the urban area of Milan (Italy) with particular regard to those provided in urban parks and forests. Five specific studies had been developed in order to analyse different ecosystem services related to biodiversity, pollution mitigation, organic C storage by soils, and cultural services.The first study proposed a methodology to spatially define the extent of the urban region (UR) of Milan. Landscape fragmentation and urban sprawl where quantified. Results revealed that the UR of Milan suffers of high degree of landscape fragmentation throughout the area, with the major fragmented territories in the north of the city Milan (Monza and Varese). Urban sprawl showed an increasing trend in the last 50 years, reaching alarming values to date. In the second study the role of urban forests in providing suitable habitats for biodiversity was analysed.It analysed which environmental features of the urban environment affected biodiversity patterns at different scales and how vegetation structure influenced the presence of different birds species. The study showed how the biodiversity patterns found can be explained by considering the effects of environmental features acting at different scales and that urban green areas can therefore be actively managed by foresters and city planners to preserve the biological diversity that they harbour. The third study represents a preliminary work that aimed at analyse the hydrocarbon-degrading potential of epiphytic microbial communities on Platanus x acerifolia, trees common used in an urban area. The fourth study deal with the estimation of organic C storage by urban soils of parks, forests and other typology of urban land covers. Mean C stock found for the urban soils of Milan was comparable to values found for the agricultural soils by previous studies. C stock was found higher for parks compared to other areas, but no clear differentiation has been found in order to define a typical C stock for each land cover or use type. Results highlight how the complex heterogeneity of urban soils together with the uncertainty of their origins, their history and management may summarize the reasons of the limitation in our capacity to model their characteristics. The fifth study analysed cultural ecosystem services (CES) perceived by citizen in one of the larger park of the study area (Parco Nord). The study aimed to present a methodology to integrate CES mapping (PPGIS) with decision support in land use planning. A comparison analysis with cultural benefits perceived by people and those intended to be provided by park management was performed. Results showed places in the park that had bundles of different values, and other places with clusters of the same value type. Comparison analysis revealed hotspot and coldspot of CES in terms of richness.

The removal of indigenous forest and associated fragmentation of habitats has probably had significant impacts on the diversity of stream communities in New Zealand. In this study I investigated the effects of forest fragmentation on stream invertebrate communities on Banks Peninsula. Six catchments were investigated, three with continuous indigenous forest in the riparian zone and three with fragmented indigenous riparian forest. An extensive benthic survey was conducted at three sites in each river catchment, one downstream on the mainstem of the river and two sites in different headwater tributaries. Adult sampling, consisting of malaise and sticky trapping, was also conducted at a sub-set of sites. Taxonomic richness of both the benthic and adult communities was significantly higher in continuous forest than in fragmented forest, and the composition of benthic communities also differed between continuous and forest fragments. Furthermore, benthic invertebrate densities were higher in fragments than continuous forest sites. The fragments in the headwaters were more likely to support forest specialist taxa (e.g. the stonefly Zelandobius wardi, and the caddisfly Costachorema peninsulae), than the downstream fragments. My results indicate that forest fragmentation has resulted in marked changes in benthic communities on Banks Peninsula, and that location of the fragment within the catchment also is important in influencing the diversity and composition of benthic communities. The maintenance of indigenous forest in the headwaters of streams may be essential for the persistence of endemic and forest specialist taxa on Banks Peninsula.

There are an overwhelming number of biodiversity indices and indicators available for ecologists and conservationists to use when seeking to understand how biodiversity responds to human disturbance. In choosing between measures there is often an underlying assumption that if a measure works well for one group it will be equally applicable to another. In this study, I use multiple taxa to explore the performance of a wide range of alpha and beta diversity measures for studying biodiversity responses to human disturbance in tropical forest. I sampled 18 sites along a gradient of human disturbance from primary tropical forest to banana monocultures in Peru. I chose three taxonomic groups and one audio approach, which have all been suggested to be useful indicators for studying biodiversity responses to disturbance: orchid bees (n = 1783), dung beetles (n = 3787), butterflies (n = 2506) and soundscape samples (n = 6600). This allowed me to identify how these groups responded to disturbance, which diversity measures were most sensitive for detecting those changes and whether the same measures were suitable for all groups. I used Hill numbers to measure alpha diversity and explored beta diversity by looking at changes in community composition and two new measures of beta diversity: redundancy and representativeness. To see how the diversity patterns changed when taxonomic similarity was considered, I used a recently developed family of similarity-sensitive diversity measures and compared the results of these against more traditional measures. I found that the diversity indices that were best for detecting disturbance patterns varied widely among taxonomic groups. For dung beetles, species richness and community composition were the most effective measures, whereas these performed poorly for orchid bees. Abundance and redundancy were more sensitive for detecting a response to disturbance in orchid bees. Using the butterfly dataset, I show that the inclusion of species similarity completely changed the diversity patterns found across the disturbance gradient. The similarity of species present in a community is likely to be important for the preservation of evolutionary adaptability and the provision of ecosystem functions and I therefore suggest that diversity measures based on similarity will be a useful additional tool for conservation and impact assessments. Acoustic diversity showed unintuitive responses to disturbance, with higher diversity detected in more disturbed forest, and more research is required to assess the performance of different acoustic indices in rainforest environments. Overall, my results demonstrate the importance of choosing diversity indices carefully to suit the taxa being studied to avoid missing important ecological responses, including a consideration of species similarity. I recommend that, where possible, multiple diversity indices and taxonomic groups should be used to reduce this risk and provide a comprehensive understanding of ecosystem patterns in response to environmental change.

Neste trabalho avaliámos o impacto que a perturbação humana das comunidades da floresta nativa da ilha Terceira (Açores) tem sobre a riqueza específica e nas interações ecológicas entre plantas e polinizadores. Para o efeito selecionámos dois locais emparelhados (um bem conservado e outro degradado), em duas áreas de estudo (Lomba e Pico Galhardo) e analisámos a integridade das redes ecológicas planta-polinizador. Constatámos que nas áreas bem conservadas as interações são dominadas por espécies nativas, enquanto que nas áreas perturbadas, apesar da prevalência de plantas introduzidas, os polinizadores nativos têm um papel relevante. Em cada área houve apenas uma planta que concentrou as visitas dos polinizadores, que na sua maioria pertenceram à ordem Diptera e tiveram hábitos generalistas; Biodiversity and plant-pollinator interactions in native forest areas of Terceira island (Azores) Abstract: In this work we evaluate the effect of anthropogenic disturbance in native forest communities of Terceira island (Azores) on species richness and on plant-pollinator ecological interactions. We selected paired sampling sites (one well-preserved and one disturbed) in two study areas (Lomba and Pico Galhardo) and we analysed plant-pollinator networks integrity. We found that native species dominate in well-preserved sites whereas in disturbed sites, despite the prevalence of introduced plants, native pollinators play an important role. In each area there was a plant that received most of the insect visits, being these mainly from Diptera order and having generalist behaviour.

The thesis outlines the impacts produced on local indigenous people by the protection of the Ngel Nyaki Forest Reserve in Taraba State, eastern Nigeria. After locating my work in various fields of literature and providing detailed background information on the area in which I conducted my fieldwork and the people who inhabit that area, I proceed onto the core of my thesis, which is two-fold. Firstly, I outline the impacts produced on the local people who inhabit the settlements surrounding the reserve. I elucidate the social, cultural, psychological, economic, and residential impacts of protecting the reserve. Second, I show how local people have adapted to these profound impacts. I show that they have negotiated the effects in various ways, including migration, livelihood diversification and shifting economic dependencies.