Rozprawy doktorskie na temat „High altitude ecology”

Although knowledge of peatland CH₄ and CO₂ exchange in temperate mountain ecosystems is available, information about carbon (C) exchange in peatlands of the Andean mountains is limited and these ecosystems may behave differently given the particular characteristics of the Andean tropics. These ecosystems are highly productive and under pressure by grazing. Our first objective was to measure baseline carbon dioxide (CO₂) and methane (CH₄) flux in an undisturbed peatland in Cayambe-Coca National Park. Our second objective was to quantify CO₂ and CH ₄ fluxes in an intensively cattle grazed peatland near Antisana Ecological Reserve. CO₂ and CH₄ effluxes were measured using a static chamber method. The mean NEE values for the undisturbed and disturbed site were -0.69 ± 0.08 and -1.25 ± 0.13 g CO₂ m ^-2 hr^-1 respectively. A significant correlation between microtopography and CO₂ and CH₄ flux was found in the undisturbed site, with higher NEE, GPP, ER and CH₄ values in hummocks than in lawns. Microtopography doesn’t seem to be a controller of CO ₂ efflux in the grazed site, although the NEE and GPP rates are higher than those found in the undisturbed site, and show a linear relationship with vegetation cover. CH₄ emissions in the undisturbed site were low (8.1 ± 1.17 mg CH₄ m^-2 d ^-1). However, CH₄ emissions at the grazed site were very high (132.25 ± 34.22 mg CH₄ m^-2 d ^-1), which might be attributed to the high physical impact and inputs from cattle. In summary, it appears that cattle grazing may be capable of large changes to C exchange and greenhouse gas fluxes in Andean peatlands.

Includes bibliographical references
Eastern high - altitude grasslands of South Africa are centres for endemism and harbour fauna and flora of regional and international conservation concern. This area also provides important ecological services such as provision of water to communities downstream. Sweet and sour veld support beef livestock farming during summer months. The aesthetic beauty of the region makes the area a prime tourist destination too. More recently the area is becoming a target of other agricultural projects such man - made forests. Other new developments that need to be mitigated against are development of renewable energy projects such as pumped water schemes to generate electricity or wind farms. Additional habitat is lost when these projects are connected to the national grid. In this thesis, I use bird data and vegetation data to compare, contrast and suggest management tools to manage this area. I present data that I collected at Ingula Pumped Storage Scheme spanning five years from the beginning of the construction of the scheme to near its completion in 2012 as a case study to manage similar habitats. Chapter 1 presents a brief overview of ecological importance of this area and the history behind the construction of pumped storage scheme at Ingula. A literature review in Chapter 2 investigates management tools to manage these grasslands for avian diversity. Fire and grazing is a key management tool cited to make habitat suitable for birds. While few studies from this type of grassland exist, studies from outside South Africa suggest that fire and grazing supplement each other as management tool to make habitat suitable for species with contrasting ecological requirements. A mosaic of grass heights and cover across the landscape translates to species habitat suitability. Chapter 3 explores species richness through years, seasons and impact of grass height and cover on bird species richness. Species richness was highest in summer suggesting that management should make habitat for species suitable in summer when most priority species are likely to use the habitat. The main disadvantage of using bird species richness is that fieldworkers must know their species well. Secondly, use of species richness must be treated with caution because this method does not account for species detectability in time and in space. In Chapter 4 I use hierarchical distance sampling models which take into account both the detection and the biological process. To demonstrate this I used common grassland bird species which can easily be identified during monitoring. The downside of this approach is that because these species are common and therefore occur almost everywhere, they may not easily respond to lack of habitat heterogeneity. The technical disadvantage of using this method is to accurately allocate species to within distance bands, making this method challenging for fieldworkers. Chapter 5 presents random plot occupancy which records only detection - nondetection of birds during repeated plot surveys. This method accounts for observational and biological processes too and in addition implements rigorous statistical inferences to predict how birds respond to habitat variable s as influenced by management decision on fire and grazing. Finally, adverse weather conditions may hamper surveying all plots in some years. Through occupancy modelling it is possible to predict species occupancy on plots that were not surveyed during some years and finally this method has been improved to include rare species. This is my preferred method to monitor management effect on habitat suitability for birds at Ingula. Adaptive management, a pillar of which is adaptive monitoring is a new paradigm shift in conservation. In Chapter 6, I capture interactions between burning and grazing and effects on grass height and cover to predict habitat suitability for birds including large threatened Ingula birds using a simulation models. This model sets a stage for implementing adaptive management through experimental plots to capture a set of management uncertainties regarding the use of fire and grazing as management tools. Chapter 7 summarizes the thesis and acknowledges that Ingula consists of other equally important habitat and ecosystem such as cool moist mountain forest and matrix of grassland wetland that equally need to be conserved.

This thesis contributes to the understanding of two of the most intriguing questions that forest ecologists have faced over recent decades: 1) how high diversity is maintained in species-rich ecosystems; and 2) what is the role of spatio-temporal environmental variation in structuring forest communities. The aims of the research were to ascertain how species composition varies both spatially and temporally and how changes in the vegetation can be understood in the context of species coexistence theories (niche versus neutral). A group of 38 sympatric species, including 9 species of Quercus, on which little ecological research has been undertaken, were used in this study. The data used in this project include eleven years of periodic remeasurements of permanent plots established in high-altitude oak forests in Mexico. Adult, sapling and seedling trees were studied as well as their environmental surrounding. Spatial and temporal variations in forest composition were analysed using multivariate statistical approaches. The results show that there are discrete communities in these mixed oak forests that correspond to specific environments. At a broad scale the study area can be classified into two floristic zones, a mesic zone characterised by associations that include Quercus candicans, Q. laurina and Q. castanea and; a xeric zone dominated by Q. crassipes. However of a finer scale of analysis important variation in composition was associated with different life stages of the trees, with adult trees showing much stronger environmental associations than seedlings and saplings. Successional pathways and rates vary at relatively fine scales. This may be as a result of dominance alternation between dominant canopy species. Micro-niche zonation processes caused by a high degree of environmental heterogeneity combined with individual species traits explain the coexistence of phylogenetically similar sympatric Quercus species. A hierarchy of processes, each acting at a different spatial and temporal scale, determines species diversity and coexistence. The overall findings support the idea that niche differentiation rather than chance events such as dispersal limitation, are more important in permitting species coexistence.

Global declines and disappearances of amphibians from high altitude, pristine habitats have been reported in recent years. To date the cause of many of these declines and/or disappearances has not been identified. Although it is well documented that life history characteristics of temperate amphibians are influenced by altitude (due to systematic variation of temperature with altitude), little work has been carried out on the effects of altitude on Australian anurans. This lack of ecological data is a major impediment to identifying the causal factors responsible for amphibian declines. Due to differences in life history characteristics, high altitude populations may be less resilient than their lowland counterparts and subsequently may be more vulnerable to extinction. Consequently, the main aim of this study was to determine whether altitude influenced life history characteristics and ultimately population resilience of anurans in the southeast Queensland region. Six anuran species; Litoria chloris, L. lesueuri, L. pearsoniana (Anura: Hylidae), Mixophyes fasciolatus, M. fleayi and M. iteratus (Anura: Myobatrachidae) were studied over three field seasons (1997-1999) in 18 sites of varying altitude (100-950m) in the southeast Queensland region. The life history characteristics examined were: activity and breeding season length, fecundity and egg size, number of clutches produced per season, tadpole growth and development rates, longevity, age at maturity, reproductive life span, average lifetime fecundity, survival and recapture rates. The data were collected using a combination of field-based surveys (body sizes, clutch sizes, and survival and recapture rates), museum specimen dissections (clutch and egg sizes), reciprocal transplant field experiments (tadpole growth and development rates) and skeletochronology (longevity, age at maturity, reproductive lifespan and average lifetime fecundity). On average, high altitude populations of all species had shorter breeding and activity seasons than low altitude populations (up to 10 weeks less in some cases). The magnitude of the difference in breeding season length varied among years depending on the average temperature and rainfall for the year; i.e. differences appeared greater in warmer and wetter years. Within a population males had longer breeding and activity seasons than females. Although breeding season length varied with altitude, the number of nights that individuals were active within the breeding season did not vary; i.e. low altitude populations were not active for more nights despite having a longer breeding season. This result was attributed to the absence of a relationship between individual activity and environmental variables (air temperature, rainfall, etc.) in many of the populations. Generally, intraspecific clutch size did not vary significantly with altitude. This result was due to the absence of a significant relationship between female body size and altitude (as clutch size is proportional to female body size). Egg size also did not vary with altitude however, suggesting egg size may be canalized (i.e. fixed) in these species. Results also suggest that females of these species only produce one clutch of eggs per season. Interspecific differences in reproductive characteristics largely reflected differences in reproductive mode, larval habitat and female body size. Altitude negatively influenced growth and development rates in L. chloris and development rates in L. pearsoniana. Tadpoles raised at high altitudes were also generally larger at each Gosner Development Stage in both species. The results of the reciprocal transplant experiments suggested that most of the variation in growth and development rates was due to environmental factors (water temperature) rather than genetic or maternal factors. Altitude or genetic factors did not significantly affect tadpole survival in either species. The results suggest that tadpoles occurring at high altitudes take longer to reach metamorphosis and do so at a larger size than their lowland counterparts. With the exception of L. lesueuri, skeletochronology was suitable for age estimation in the study species. Altitude had a significant effect on the age at maturity or longevity in some of the species, however there were trends toward older individuals and older ages at maturity in high altitude populations for the remaining species. Females were generally older than males for all species and in the case of longer-lived species (i.e. Mixophyes spp.) also tended to be older when breeding for the first time. The large overlap of body sizes of individuals of different ages demonstrates that body size is a poor indicator of age in these species. This is the first study to estimate average lifetime fecundity for more than one amphibian species and/or population. The results suggest that the absence of significant altitudinal variation in the average lifetime fecundity of different populations is due to tradeoffs made by females (current reproduction vs. survival). There was no significant altitudinal variation in annual survival and recapture rates in any of the species, and generally there was no difference in the survival and recapture rates of males and females in each population. Within a year, monthly survival and recapture rates were more variable at low than high altitudes and this was attributed to the longer breeding season of low altitude populations. The results did not support previous studies that suggested there was a size bias in survival and recapture rates. The shorter breeding seasons, slower growth and development rates, older age at maturity and greater longevity found in the high altitude study populations will result in increased generation time in those populations. In turn, increased generation time can cause high altitude populations to be less resilient (i.e. population takes longer to return to equilibrium after a disturbance away from equilibrium) (Pimm et al. 1988, Pimm 1991) and ultimately more vulnerable or prone to extinction or decline. The majority of unexplained global amphibian declines have occurred at high altitudes in tropical and subtropical areas. These latitudinal patterns may be explained by the narrow range of environmental tolerances exhibited by tropical organisms resulting in mountains being effectively “higher” in the tropics. Consequently, high altitude tropical species are likely to be even more vulnerable than temperate species occurring at similar altitudes. Further work on the effects of geographic variation, especially interactions between altitude and latitude are needed to evaluate the hypotheses for the causes of these declines and disappearances.
Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Environmental and Applied Science
Science, Environment, Engineering and Technology
Full Text

This thesis presents the results of a study to examine long-term forest dynamics in the high-altitude mountains of West-Central Mexico. Vegetation dynamics on temporal scales ranging from 10² to 10³ years were reconstructed in order to provide essential information on the temporal variability of ecological patterns and processes in these forests; information that is of direct relevance for their current and future conservation and management strategies. Vegetation and palaeoecological methods undertaken included fossil and modern pollen analysis, vegetation surveys, microfossil charcoal analysis, magnetic susceptibility, inorganic and organic geochemistry, radiocarbon and ²¹⁰Pb dating. These were used to evaluate the long-term dynamics of three forest types; Pine Forest, Cloud Forest and Transitional Forest on timescales spanning the past 4260, 1340 and 1230 years respectively. The main drivers of change were climate and disturbance events induced by climate fluctuations, for example increased fire frequency. The reconstructed records indicate that the sequences from the Cloud Forest and the Transitional Forest spanned two wet and one dry climatic interval while the Pine Forest sequence spanned two dry and two wet periods. The impact of these climatic fluctuations was significant on all three forest types and resulted in variations in forest diversity, taxonomic turnover and successional change. The climate change episodes observed in these records seem to be the local manifestation of climatic events that were occurring throughout Mexico at these intervals in time. Human influences were evident in the three forests through the appearance of cultural taxa, particularly during the driest period (~ 1200 yr BP). There is little evidence from these records, however, to suggest a widespread clearance of the landscape for agriculture. Results from this study support the current conservation and management recommendations for Cloud Forest to exclude timber extraction, grazing and agricultural activities from this forest type. In the Pine Forest, human interventions such small-scale agriculture, prescribed burning and silvicultural actions are in agreement with the longterm pine ecology and as such, total exclusion of human activities is not necessary. For the Transitional Forest, results from this study suggest that there needs to be the establishment of adequate plans to reduce frequent fires to arrest the development of prone-to-fire taxa.

Global declines and disappearances of amphibians from high altitude, pristine habitats have been reported in recent years. To date the cause of many of these declines and/or disappearances has not been identified. Although it is well documented that life history characteristics of temperate amphibians are influenced by altitude (due to systematic variation of temperature with altitude), little work has been carried out on the effects of altitude on Australian anurans. This lack of ecological data is a major impediment to identifying the causal factors responsible for amphibian declines. Due to differences in life history characteristics, high altitude populations may be less resilient than their lowland counterparts and subsequently may be more vulnerable to extinction. Consequently, the main aim of this study was to determine whether altitude influenced life history characteristics and ultimately population resilience of anurans in the southeast Queensland region. Six anuran species; Litoria chloris, L. lesueuri, L. pearsoniana (Anura: Hylidae), Mixophyes fasciolatus, M. fleayi and M. iteratus (Anura: Myobatrachidae) were studied over three field seasons (1997-1999) in 18 sites of varying altitude (100-950m) in the southeast Queensland region. The life history characteristics examined were: activity and breeding season length, fecundity and egg size, number of clutches produced per season, tadpole growth and development rates, longevity, age at maturity, reproductive life span, average lifetime fecundity, survival and recapture rates. The data were collected using a combination of field-based surveys (body sizes, clutch sizes, and survival and recapture rates), museum specimen dissections (clutch and egg sizes), reciprocal transplant field experiments (tadpole growth and development rates) and skeletochronology (longevity, age at maturity, reproductive lifespan and average lifetime fecundity). On average, high altitude populations of all species had shorter breeding and activity seasons than low altitude populations (up to 10 weeks less in some cases). The magnitude of the difference in breeding season length varied among years depending on the average temperature and rainfall for the year; i.e. differences appeared greater in warmer and wetter years. Within a population males had longer breeding and activity seasons than females. Although breeding season length varied with altitude, the number of nights that individuals were active within the breeding season did not vary; i.e. low altitude populations were not active for more nights despite having a longer breeding season. This result was attributed to the absence of a relationship between individual activity and environmental variables (air temperature, rainfall, etc.) in many of the populations. Generally, intraspecific clutch size did not vary significantly with altitude. This result was due to the absence of a significant relationship between female body size and altitude (as clutch size is proportional to female body size). Egg size also did not vary with altitude however, suggesting egg size may be canalized (i.e. fixed) in these species. Results also suggest that females of these species only produce one clutch of eggs per season. Interspecific differences in reproductive characteristics largely reflected differences in reproductive mode, larval habitat and female body size. Altitude negatively influenced growth and development rates in L. chloris and development rates in L. pearsoniana. Tadpoles raised at high altitudes were also generally larger at each Gosner Development Stage in both species. The results of the reciprocal transplant experiments suggested that most of the variation in growth and development rates was due to environmental factors (water temperature) rather than genetic or maternal factors. Altitude or genetic factors did not significantly affect tadpole survival in either species. The results suggest that tadpoles occurring at high altitudes take longer to reach metamorphosis and do so at a larger size than their lowland counterparts. With the exception of L. lesueuri, skeletochronology was suitable for age estimation in the study species. Altitude had a significant effect on the age at maturity or longevity in some of the species, however there were trends toward older individuals and older ages at maturity in high altitude populations for the remaining species. Females were generally older than males for all species and in the case of longer-lived species (i.e. Mixophyes spp.) also tended to be older when breeding for the first time. The large overlap of body sizes of individuals of different ages demonstrates that body size is a poor indicator of age in these species. This is the first study to estimate average lifetime fecundity for more than one amphibian species and/or population. The results suggest that the absence of significant altitudinal variation in the average lifetime fecundity of different populations is due to tradeoffs made by females (current reproduction vs. survival). There was no significant altitudinal variation in annual survival and recapture rates in any of the species, and generally there was no difference in the survival and recapture rates of males and females in each population. Within a year, monthly survival and recapture rates were more variable at low than high altitudes and this was attributed to the longer breeding season of low altitude populations. The results did not support previous studies that suggested there was a size bias in survival and recapture rates. The shorter breeding seasons, slower growth and development rates, older age at maturity and greater longevity found in the high altitude study populations will result in increased generation time in those populations. In turn, increased generation time can cause high altitude populations to be less resilient (i.e. population takes longer to return to equilibrium after a disturbance away from equilibrium) (Pimm et al. 1988, Pimm 1991) and ultimately more vulnerable or prone to extinction or decline. The majority of unexplained global amphibian declines have occurred at high altitudes in tropical and subtropical areas. These latitudinal patterns may be explained by the narrow range of environmental tolerances exhibited by tropical organisms resulting in mountains being effectively “higher” in the tropics. Consequently, high altitude tropical species are likely to be even more vulnerable than temperate species occurring at similar altitudes. Further work on the effects of geographic variation, especially interactions between altitude and latitude are needed to evaluate the hypotheses for the causes of these declines and disappearances.

In the archaeological literature, mountains are often portrayed as the boundaries between inhabited spaces. Yet occupying high elevations may have been an adaptive choice for ancient peoples, as rapidly changing elevations also offer variation in climate and resources over a relatively small area. So what happens, instead, if we put mountain landscapes at the center of our analyses of prehistoric seasonal rounds and ecological adaptation? This Ph.D. argues that, in order to understand any landscape that includes mountains, from the Alps to the Andes, one must include the ecology and archaeology of the highest elevations. Specifically, I base my findings on new fieldwork and lithic collections from the Absaroka and Beartooth Mountains in the Greater Yellowstone Ecosystem (GYE) of the Rocky Mountains, which was a vital crossroads of prehistoric cultures for more than 11,000 years. I include five interlocking analyses. First, I consider the impacts of anthropogenic climate change on high elevation cultural resources, focusing on the diminishing resiliency of ancient high elevation ice patches and the loss of the organic artifacts and paleobiological materials they contain. Second, I create a dichotomous key for chronologically typing projectile points, suggesting a methodological improvement for typological dating in the GYE and for surface archaeology more broadly. Third, I use obsidian source data to consider whether mountain people were a single, unified group or were represented by a variety of peoples with different zones of land tenure. Fourth, I consider high elevation occupation in both mountain ranges as part of the seasonal round, using indices of diversity in tool types and raw material to study how the duration of those occupations changed through time. And, finally, I test the common contention that ancient people primarily used mountains as refugia from extreme climatic pressure at lower elevations. Ultimately, I find that, in both mountain ranges, increased high elevation activity is most highly correlated with increased population, not with hot, dry climatic conditions. In other words, the mountains were more than simply refugia for plains or basin people to occupy when pressured by climatic hardship. In addition, between the Absarokas and the Beartooths the evidence suggests two different patterns of occupation, not a monolithic pan-mountain adaptation. These results demonstrate the potential contributions of surface archaeology to our understanding of prehistory, and have important implications for the way we think about mountain landscapes as peopled spaces in relation to adjacent lower-elevation areas.

The main aim of this study was to determine if Ischyrolepis sieberi, a common restiod species found at high altitudes in the Cederberg captures fog to supplement its water needs. This was done by comparing the isotopic ratios of δD and δ¹⁸O in captured fog, rainwater, and stream water and comparing these to the δD and δ¹⁸O values found in the xylem water of Ischyrolepis sieberi plants growing at the study site. The δD values of the collected fog samples were enriched relative to rainwater, stream water, and xylem water from I. sieberi, however these differences were not significant. The δ¹⁸O values of the I. sieberi xylem water were significantly (p < 0.01) more enriched than rain, stream, and fog water. The xylem water of I. sieberi was depleted in δD and enriched in δ¹⁸O relative to all other water sources. The plants therefore did not appear to be utilizing fog during the three months of this study. The δ¹⁸O values of I. sieberi were consistently 4-6‰ enriched compared to rainwater, suggesting that they are utilizing rainwater, which has undergone fractionation due to evaporation in the soil before being taken up by the plants. This study was run during the wet winter months. The δD and δ¹⁸O values from previous data suggest that the I. sieberi plants do utilize fog during the dry summer months.

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O Parque Estadual da Serra do Papagaio (PESP), situado na porção Meridional da Serra da Mantiqueira, sul de Minas Gerais, representa uma grande extensão de formações vegetacionais altimontanas com altitudes que alcançam 2.350 m. O objetivo deste trabalho foi conhecer a composição florística dos campos de altitude do PESP, suas relações fitogeográficas com outras áreas campestres das regiões Sul e Sudeste do Brasil e analisar a estrutura da vegetação ao longo de um gradiente altitudinal. Expedições mensais de campo foram realizadas entre maio de 2015 e outubro de 2016 para coleta de material botânico e realização dos inventários fitossociológicos. Para avaliar a estrutura da vegetação foi utilizado o método de interceptação em linha, com alocação de nove áreas abrangendo três faixas altitudinais entre 1.650 m e 2.050 m. Para analisar as relações fitogeográficas foram selecionadas 14 localidades do Sul e Sudeste do país. Foram realizadas análises de similaridade quantitativas e qualitativas além do cálculo da diversidade para cada faixa altitudinal para avaliar a formação de grupos relacionados à altitude. O primeiro capítulo traz a composição florística dos campos de altitude do PESP, onde foram encontradas 276 espécies, 159 gêneros e 48 famílias de angiospermas, sendo Asteraceae a família mais rica (58 spp.) e Baccharis o gênero mais representativo (12 spp.). Foram encontradas onze espécies sob algum grau de ameaça e duas espécies endêmicas do PESP. As análises fitogeográficas mostraram uma grande dissimilaridade florística entre as 14 localidades analisadas, indicando que as formações campestres são singulares e demandam atenção especial para a conservação. O segundo capítulo apresenta a distribuição das espécies ao longo de um gradiente altitudinal. Foram encontradas 96 espécies nas linhas amostradas, sendo Poaceae (64,3%), Melastomataceae (11,3%) e Asteraceae (8,7%) as famílias com maiores valores de cobertura. A diversidade de Shannon (H’) para cada altitude apontou um padrão similar na distribuição espacial das espécies, enquanto as análises de similaridade demonstraram um forte agrupamento das áreas localizadas em faixas altitudinais comuns, elucidando a importância da conservação dos campos de altitude para a manutenção da biodiversidade da flora altomontana.
The Parque Estadual da Serra do Papagaio (PESP) is located in the southern portion of Serra da Mantiqueira, south of Minas Gerais and represents a large expanse of altitudinal vegetation formations with altitudes that reach 2.350 m. The aim of this work was to carry out the floristic survey of the PESP altitude fields (campos de altitude), their phytogeographic relationships with other rural areas of Southern and Southeastern regions of Brazil, and to analyze the vegetation structure along an altitudinal gradient. Monthly expeditions were carried out between May 2015 and October 2016 for the collection of botanical material and the realization of phytosociological inventories. The line intercept method was used to evaluate the vegetation structure. Were inventoried nine areas covering three altitudinal ranges between 1.650 m and 2.050 m. In order to analyze the phytogeographic relations, were selected 14 localities of Brazil South and Southeast. Quantitative and qualitative similarities analyzes were carried out. In addition, the diversity index (H') were calculated for each altitudinal range in order to evaluate the formation of groups related to altitude. The first chapter presents the floristic composition of the PESP altitude fields, where 276 species, 159 genera and 48 families of angiosperms were found, with Asteraceae being the richest family (58 spp.) and Baccharis the most representative genus (12 spp.). Eleven species are in some threatness category and two species were considered endemic to the PESP. The phytogeographic analyzes showed a great floristic dissimilarity between the 14 localities analyzed, indicating that the formations are unique and require special attention for conservation. The second chapter presents the distribution of the species along an altitudinal gradient. 96 species were found in the sampled lines, with Poaceae (64.3%), Melastomataceae (11.3%) and Asteraceae (8.7%) being the families with the highest coverage values. The diversity of Shannon (H') for each altitude showed a similar pattern in the spatial distribution of species, while the similarity analyzes demonstrated a strong grouping of the areas located in common altitudinal bands, elucidating the importance of the conservation of altitude fields for the maintenance of the biodiversity of the high altitude flora.

Les alpages laitiers des alpes du nord externes (france) representent un type de systeme ecologique original refletant les effets des pratiques d'eleveurs (fertilisation, paturage) combines aux contraintes du milieu montagnard (etage subalpin). Face aux mutations recentes des modes d'exploitation des alpages, des recherches ont ete engagees pour comprendre et prevoir l'impact des pratiques pastorales sur la dynamique de ces pelouses d'altitude. Nous proposons un modele d'evolution de la composition botanique qui integre l'effet des facteurs anthropiques et celui des facteurs edaphiques. Ce modele s'appuie sur une analyse factorielle des correspondances portant sur un echantillonnage de six cent releves floristiques couvrant l'ensemble de la zone d'etude. La reconstitution des trajectoires dynamiques se fait principalement par une approche synchronique, completee par des observations diachroniques qui ont permis de preciser les vitesses d'evolution de la vegetation. L'essentiel des travaux porte sur des situations de deprise: la dynamique de la vegetation y reflete une degradation de la fertilite des sols consecutive a l'abandon ou a l'allegement de la fertilisation. Cette evolution est generalement lente: deux a cinq decennies sont necessaires pour que l'on enregistre des changements notables dans la composition botanique. Les resultats mettent egalement en evidence l'influence des parametres edaphiques sur les limites et le deroulement de ces successions. Les modalites d'evolution de la vegetation et la hierarchie des facteurs sont precisees dans des trajectoires-types qui permettent d'adapter localement la demarche de diagnostic ecologique. Differents indicateurs, relatifs aux processus physiologiques ou demographiques d'evolution de la vegetation, sont testes afin de preciser ou d'anticiper le diagnostic floristique. Les indices de diversite specifique ou factorielle restent d'un usage delicat en raison de leur sensibilite a l'egard des methodes d'echantillonnage et d'observation. Les indices de nutrition minerale font rapidement apparaitre les modifications d'equilibres trophiques qui suivent l'arret ou la reprise de la fertilisation

Common to the temperate floras throughout sub-Saharan Africa is a group of taxa with strong ties to the Cape Floristic Region (CFR) (≈ Cape elements). Their distribution is limited to the eastern escarpment of Africa (e.g. the Drakensberg Alpine Centre - DAC), on nutrient-rich humic soils, as well as on isolated sandstone outcrops of low elevation, on nutrient-poor soils (e.g. the Pondoland Centre - PC), suggesting that intrinsic soil fertility is not the primary determinant of their distribution. The principal aim of this study was to determine which aspect of the edaphic environment of the DAC is most influenced by temperature, that may indirectly render it nutrient-poor and therefore provide suitable niches for Cape elements, as in the PC. A multidisciplinary approach involving aspects of plant biogeography, plant ecology, plant ecophysiology and soil chemistry was therefore adopted. The study regions were the DAC, PC and the KwaZulu-Natal Midlands. The flora of the DAC was resurveyed for this study, and is richer than previously thought: 2818 native taxa, most of which (2520) are angiosperms. The phytogeography of the DAC and PC is discussed, and comparisons are made with the floras of KwaZulu-Natal and the CFR. Their climatic environments, as well as those for the CFR and Sneeuberge, were compared using rainfall and temperature data from a range of sources. These climatic regimes were correlated with the floristic patterns of Cape elements for the high-altitude regions of South Africa and Lesotho. Altitude and rainfall increased, and temperature decreased, as the number of Cape elements increased towards the DAC. This study provided a contemporary inventory of the Cape elements of the DAC and PC. A total of 89 genera are recognised as Cape elements, of which 60 (c. 67%) are shared between the two regions. The highest number of Cape elements recorded for the eastern escarpment was the DAC (72 genera), with the highest number from all sites analysed being the PC (77 genera). The most Cape elements are contributed by the Asteraceae, Scrophulariaceae, Iridaceae, Fabaceae, Orchidaceae and Restionaceae, partly due to the success of annual aerial parts and their geophytic growth forms, which are convergent in these families. Further compartmentalisation into life and growth forms shows that most Cape elements of the DAC and PC are either ericoid (and sclerophyllous) or mesic herbs and shrubs. The ecological and ecophysiological aspects of this study involved the use of reciprocal pot experiments established along a gradient of altitude from coastal hinterland to mountain, that investigated the interactions between altitude, temperature and substrate on plant productivity in sites known either to support or to exclude Cape elements. Three soils were used at each site, representative of the DAC, PC and KwaZulu-Natal Midlands. The interactions between 'soil' and 'site' (≈ the climatic environment) were quantified using a temperate test taxon (Diascia) that has a strong Cape-centred distribution. Plant characters relating to morphology and nutrient content, and soil characters relating to fertility, were used as the basis for comparing treatment effects (soil-site interactions). Soil nitrogen availability was assayed using pot experiments with Eragrostis curvula (Schrad.) Nees. Wheat pot experiments revealed no Al³⁺ toxicity in 'Drakensberg' soil. Non-metric multidimensional scaling (NMDS) and redundancy analysis (RDA) indicated that all soil-site interactions were significant contributors to biomass differences, and that the Cape taxon performed poorly in the nutrient-rich Drakensberg soil at low altitude. Soil samples indicated that Drakensberg soil was the most nutrient-rich, and Pondoland soil the most nutrient-poor. Although total nitrogen in Drakensberg soil was six times higher than Pondoland soil, both soils mineralised similar low levels of nitrogen at their respective spring temperatures. The result for Drakensberg soil (simulated so as to include the effect of altitude) meant that only 1.7% of its total nitrogen was mineralisable at 12°C (its mean spring temperature). These findings suggest that nitrogen mineralisation rate is a key growth-limiting factor in the DAC, exacerbated by a number of complex interactions with soil pH and organic matter. It is hypothesized that Cape elements are preadapted to high-altitude habitats. These habitats are nutrient-deprived due to low temperatures, which reduce metabolic rates and the movement of ions in cold soils. This constraint imposes nutrient-related stresses similar to those of the CFR and PC. Taxa that are adapted to the nutrient-poor soils of the CFR are preadapted to the temperature-induced 'nutrient-poor' soils of the DAC and vice versa. This 'compatibility' has allowed the reciprocal exchange of taxa between regions, as suggested by cladistic biogeographical analyses using Cliffortia, Disa, Moraea and Pterygodium. The strong overlap of Cape elements between the CFR and PC is a product of similar nutritional niches and ancient floristic continuity. The result therefore is a high number of Cape elements common to the DAC and PC.
Thesis (Ph.D.)-University of KwaZulu-Natal, Pietermaritzburg, 2004.

Thesis (M.S.)--University of Wisconsin--Madison, 2004.
Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 131-139).

Dissertação de Mestrado em Ecologia apresentada à Faculdade de Ciências e Tecnologia
Ceratium furcoides (Levander) Langhans é uma espécie invasora de fitoplâncton para as águas doces brasileiras, associada a impactos ecológicos que afetam a qualidade da água e a comunidade aquática local. Este estudo explorou as interações entre espécies fitoplanctónicas durante a invasão de C. furcoides e os vetores (variáveis meteorológicas, físicas e químicas), contribuindo para sua dominância e florescimento numa barragem subtropical de altitude (Marrecas, Sul do Brasil). O programa de monitorização foi implementado semanalmente a mensal desde 2014 (n = 116), dependendo da densidade das cianobactérias. Testes descritivos, de hipóteses, correlações e estatística multivariada (PCA e CCA) foram utilizados para compreender os padrões de distribuição temporal (sazonal e interanual) da comunidade fitoplanctónica e as variáveis ambientais. Durante o estudo, C. furcoides (Miozoa) evitou os verões e preferiu as primaveras, exibindo em outubro de 2014 a maior densidade reportada (15.865 ind.mL-1). Apresentou uma correlação com a presença de ferro, manganês e turbidez, evidenciando a sua dependência do período de mistura que re-suspende os seus cistos do fundo, ativando-os com a luz e as altas temperaturas do “epilimnion” (camada superior da coluna de água num lago estratificado) (temperatura ótima para a espécie durante a primavera). Chroomonas, Cryptomonas (Cryptophyta), Discostella (Bacillariophyta), e depois de 2016 também Chlamydomonas (Chlorophyta) foram os únicos taxa presentes durante os picos de C. furcoides. Chroomonas, Cryptomonas e Aulacoseira (Bacillariophyta), que habitam águas turbulentas, correlacionaram-se positivamente com o invasor, enquanto as Chlorophyta (Sphaerocystis, Schroederia e Monoraphidium) e as Bacillariophyta (Urosolenia, Rhizosolenia e Discostella) preferiram o verão e o outono, Cyanobacteria (Pseudanabaena). que preferiram o inverno e o outono, Ochrophyta (Mallomonas) que evitavam a primavera e Chlamydomonas sem sazonalidade, todos apresentaram correlações negativas com o invasor. Os picos de C. furcoides foram associados a maiores níveis de oxigénio dissolvido e menor riqueza de espécies. Ao longo do tempo, C. furcoides e o resto dos picos de densidade do fitoplâncton diminuíram consideravelmente mostrando, embora não conclusivamente, evidências de coexistência estável.
Ceratium furcoides (Levander) Langhans is a phytoplankton species invasive in Brazilian freshwaters, associated with ecological impacts affecting the water quality and local aquatic community. This study explored the interactions between phytoplankton species during the invasion of C. furcoides and the drivers (meteorological, physical, and chemical variables) contributing to its dominance and blooms in a subtropical high-altitude reservoir (Marrecas, Southern Brazil). The monitoring program was implemented weekly to monthly since 2014 (n=116), depending on the cyanobacteria density. Descriptive, hypothesis tests, correlations, and multivariate statistics (PCA and CCA) were employed to understand the temporal (seasonal and interannual) distribution patterns of the phytoplankton community and the environmental variables. During the study, C. furcoides (Miozoa) avoided summers and preferred springs (southern hemisphere), displaying in October of 2014 the highest density ever reported (15,865 ind.mL-1). It showed correlation with iron, manganese, and turbidity evidencing its dependency on the mixing period which resuspends its cysts from the bottom, activating them with the light and high temperatures of the epilimnion/surface (optimal temperature for the species during spring). Chroomonas, Cryptomonas (Cryptophyta), Discostella (Bacillariophyta), and after 2016 also Chlamydomonas (Chlorophyta) were the only taxa present during C. furcoides peaks. Chroomonas, Cryptomonas, and Aulacoseira (Bacillariophyta), which inhabit turbulent waters, correlated positively with the invader while, Chlorophyta (Sphaerocystis, Schroederia, and Monoraphidium) and Bacillariophyta (Urosolenia, Rhizosolenia, and Discostella) that preferred summer and fall, Cyanobacteria (Pseudanabaena) that preferred winter and fall, Ochrophyta (Mallomonas) that avoided spring, and Chlamydomonas with no seasonality, all showed negative correlations with the invader. C. furcoides peaks were associated with higher dissolved oxygen levels and lower species richness. Throughout time, C. furcoides and the rest of the phytoplankton density peaks decreased considerably showing, although not conclusively, evidence of stable coexistence.
Outro - Erasmus Mundus grant, International Master in Applied Ecology program

The westernmost spur of the Tibetan Plateau stretches to Eastern Ladakh in India. It is a region which remains poorly explored because of challenging conditions and long periods of political instability. At the same time, it is one of the highest places on earth supporting angiosperm life, which goes beyond 6000 m a.s.l. here. The whole region, due its remoteness, is practically unaffected by plant invasions and direct human activities. Thus, Ladakh represents a kind of "natural experiment", providing very long gradient of elevation suitable for comparative functional ecology as well as for testing various hypotheses concerning limitations of vascular plants. Arid climate and extreme elevations are the common factors. Our team pursued the goal of systematic botanical and ecological exploration of Ladakh, started by late Leoš Klimeš. This thesis provides insight into the main vegetation types, clonality in plants, plant-plant interactions and soil phototroph communities.

Pygmy tarsiers (Tarsius pumilus) of Central Sulawesi, Indonesia are the only species of tarsier known to live exclusively at high altitudes. This study was the first to locate and observe multiple groups of this elusive primate. This research tested the hypothesis that variation in pygmy tarsier behavior and morphology correlates with measurable ecological differences that occur along an altitudinal gradient. As a response to decreased resources at higher altitudes and the associated effects on foraging competition and energy intake, pygmy tarsiers were predicted to exhibit lower population density, smaller group sizes, larger home ranges, and reduced sexually selected traits compared to lowland tarsiers. Six groups containing a total of 22 individuals were observed. Pygmy tarsiers were only found between 2000 and 2300 m, indicating allopatric separation from lowland tarsiers. As expected, the observed pygmy tarsiers lived at a lower density than lowland tarsier species, in association with decreased resources at higher altitudes. The estimated population density of pygmy tarsiers was 92 individuals per 100 ha, with 25 groups per 100 ha. However, contrary to expectation, home range sizes were not significantly larger than lowland tarsier home ranges, and average NPL was smaller than those of lowland tarsiers. The average home range size for the observed pygmy tarsiers was 2.0 ha, and the average nightly path length (NPL) was 365.36 m. Pygmy tarsiers exhibited a nonrandom, clumped distribution near forest edges. While insect abundance and biomass were found to decrease as altitude increased, insect abundance and biomass was higher along anthropogenic edges. Thus, tarsiers within the study area may mitigate the decreased availability of insects at high altitudes by remaining close to forest edges, which in turn may be related to smaller than expected home range sizes. Further, estimates of pygmy tarsier abundance may be inflated because of increased insect abundance along anthropogenic edges. Contrary to the prediction for smaller group sizes as a response to feeding competition, the observed pygmy tarsiers lived in relatively large groups with multiple adult males. However, in support of the prediction for energetic constraints on body proportions, the observed pygmy tarsiers did not exhibit sexually selected traits. The pygmy tarsiers exhibited low sexual dimorphism and small relative testes mass, a trend opposite from lowland tarsier species, which may indicate a constraint on the development of those traits. Considered together, these results suggest that the observed pygmy tarsiers have adapted to life in an environment with limited resources. Future studies should explore the possible contributing effects of seasonality and topography.

This inquiry has been concerned with identifying aesthetic languages that make visible relationships and processes that connect body and world beyond the surface of the skin. It hypothesised that aesthetic language provides a material connection which co-enables this exchange. Examining the aesthetic dimension of the embodiment-environment intersection, this inquiry reasoned, could make tangible the material continuum generated through transient processes of living. The key sites of the home and the landscape framed the scope of this research. The methodology used to undertake this research combined multi-artform practice spanning sculpture, video, installation, and drawing, visual diary-led observation and critical reflection, theoretical research, and critical engagement with the work of other artists and practitioners working in two- and three-dimensions. An examination of subjectivity and of aesthetics as an intersection of body and world centres this research. A new materialist perspective provides a logic and drive for scrutinising this intersection. New materialism unsettles traditional assumptions about the passivity of matter. It provides a framework for re-imagining the materiality of the world and the position of human subjectivity within it: a re-imagining, this research contends, that the current ecological crisis demands. The notion of aesthetics used in this inquiry is an embodied aesthetics that refers to the meaningful sensuousness that adheres and orients the body in the world. Ideas from John Dewey and the field of everyday aesthetics informed critical engagement in this embodied aesthetics through creative practice. This approach enabled a dialogue between special aesthetic experiences, everyday aesthetics, and habitual perception to emerge in the research. This research used aesthetics to examine how spaces are demarcated and different experiences enabled. Over time, the home as it is situated within the landscape became analogous for the body’s intertwining with the environment. In this context, the material passage of water through the home provided a powerful and instructive embodiment of this intertwining, revealing both the demarcation and the continuity of disparate spaces. The final body of artwork is an installation that integrates the key aesthetic languages developed through this inquiry to form a three-dimensional river that is animated with the everyday sounds of water and the textures of domestic warmth. It is titled Oikos, the Greek root for ecology. ‘Oikos’ means ‘whole house and dwelling place’. The artwork reflects the multi-layering of aesthetic relationships through which our bodies fuse with this world.