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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
231

Assessing the distribution of bats in southern Africa to highlight conservation priorities

Cooper-Bohannon, Rachael January 2015 (has links)
Approximately 25% of bats globally are threatened, but limited data on African bats, which account for 20% of bat species, hinders our understanding of their conservation status across this ecologically diverse continent. This study combined: modelling techniques, to predict current species distributions for 58 southern African bat species and project past, current and future distributions of 22 endemic and near-endemic species; bat acoustic surveys, to assess landscape features influencing bat activity in arid and semi-arid regions; and conservation planning software to design a large-scale monitoring network for bats across this subcontinent. Species distribution models were employed using a robust and well established presence-only modelling technique (Maximum Entropy – Maxent) to model the current distributions of 58 species in southern Africa. Although the important eco-geographical variables were species- or in some cases family-specific, overall water availability (both temporary and permanent), seasonal precipitation, vegetation and karst (caves/limestone) areas were the most important factors associated with distribution patterns. These species distributions were then used to identify range-restricted and narrow niche breadth species, alongside other life-history strategies considered to put species at risk, such as Old World pteropodids and cave-dwelling bats to identify species most at risk. Nine of the 58 species in this study were identified as ‘at risk’. Considering range-restriction and endemism separately, the results showed that range-restricted species were a higher proportion (50%) of ‘at risk’ species than endemics (41%) but six of the nine identified species were endemic and range restricted (67%). If only areas of high species richness are prioritised, important areas with low species richness but rare, ‘at risk’ or endemic species would be excluded. Species distributions are not fixed but may shift due to changes in environmental conditions. Accurately predicting changes in species’ distributions due to anthropogenic climate change remains a fundamental challenge for conservation biologists, and this is amplified when dealing with taxa such as bats that are inherently difficult to study and in areas, such as Africa, with sparse ecological data. To better understand endemic bat species risk to climate change in southern Africa and to highlight historical and future likely refugia, Maxent was employed to forecast range-shifts for 22 southern African endemic or near-endemic species. Species distributions were projected during the Last Glacial Maximum (LGM ~22,000 BP), present (1950-2000) and future (2070: averaged 2061-2080, using IPCC5 scenarios) climatic conditions. Climate change was predicted to change species composition extensively within a relatively short timescale (within 60 years). By 2070, 86% of species modelled are predicted to have range contractions and six species were highlighted to be most at risk, with range contractions of more than 20%. The majority of southern Africa is composed or arid or semi-arid regions. Generally arid and semi-arid areas are overlooked and understudied due to low species richness, yet these areas are known to have a high proportion of endemic species. As part of this study, driven transects were carried out across arid and semi-arid areas to assess bat activity in these areas. Bat activity was recorded at 94% of the acoustic surveys, demonstrating that driven transects are an effective method of surveying bats in southern Africa. Bat activity increased at lower altitudes and higher latitudes, which characteristically have more rainfall, permanent water and vegetation. Although water has been shown in other studies to be important for bats, temporary water was not shown to influence bat activity and permanent water was positively correlated with bat activity for hipposiderids and rhinolophids and FM bats, which may reflect the fact that water features important for bats at smaller scale. The same two vegetation types that were consistently negatively correlated with bat activity were drier vegetation types (Karoo-Namib shrubland) and high salinity halophytic vegetation. Finally, a systematic conservation planning software tool (Marxan) was used to design multi-species monitoring networks that incorporated all 58 target species across the 11 ecoregions found in southern Africa. To ensure rare, endemic and range-restricted species were monitored at the same level as widespread species, species distributions (mapped using Maxent) were extracted by ecoregion. Monitoring targets (i.e. a percentage of species distribution across ecoregions) were standardised to ensure the same percentage of predicted distribution was included across all species (rare and widespread). To account for different resources and capacity, three optimal monitoring networks (minimum monitoring stations to achieve the monitoring targets) were proposed to survey 1, 5 or 10% of all species distributions within each ecoregion. The optimal solution for monitoring 1% of species distributions within ecoregions was found by monitoring 1,699 stations (survey sites), or for 5% 8,486 stations and finally for 10% 17,867 stations would be needed. In conclusion, the findings presented in this thesis have important conservation implications and have the potential to inform the practical steps required towards the introduction of a bat monitoring programme in southern Africa. While this study has highlighted challenges to African bat conservation, it has also demonstrated that an integrated and multi-disciplinary approach, using emerging techniques and conservation tools (e.g. conservation planning and automated call analysis software) can be used to fill knowledge gaps and inform conservation priorities in the absence of systematically collected data.
232

Wildlife impacts of, and public attitudes towards, small wind turbines

Tatchley, Cerian January 2015 (has links)
Global wind power generation has grown rapidly in response to targets to reduce greenhouse gas emissions as part of efforts to mitigate climate change, and to increase energy security. While much of the focus in wind energy technology to date has been on wind farms, a relatively recent development is the expansion of the micro-wind sector (turbines generating < 100 kW), and there are now over 870,000 small wind turbines (SWTs) installed globally. However, official planning guidance for SWTs in the UK and elsewhere is lacking. This may be a barrier to SWT installations if there is confusion over the requirements to gain planning permission. One reason for the lack of planning guidance is that our understanding of the wildlife impacts of SWTs is limited and therefore it is difficult to make recommendations for their mitigation. There are a range of potential negative effects wind power can exert on wildlife, in particular on birds and bats, yet to date, there has been very little published research into the wildlife impacts of SWTs. Mortality rates of wildlife at SWTs appear to be relatively low, but disturbance of bats, highly protected species, near SWTs has been previously demonstrated. However, the extent (if any) of this disturbance at habitat features of known importance was unclear. Therefore this thesis used acoustic surveys of bat activity to quantify disturbance of use of linear features (e.g. hedgerows, treelines), habitat important to bats for commuting and foraging, caused by SWTs. Firstly, bat activity did decline after experimental installation of SWTs 5m away from linear features. This decline was species-specific with Pipistrellus pygmaeus showing declines in activity in close proximity to the SWT associated with SWT operation, while P. pipistrellus activity declined in response to installation both at the SWT site and 30m away. Secondly, bat use of linear features is lower when SWTs are located nearby. In particular, P. pygmaeus activity at linear features is lower the closer a SWT is to the feature, and at high wind speeds Myotis spp. use of linear features is similarly lower where SWTs are located nearby. This disturbance did not dissipate along the linear features away from the SWT for at least 60m. This is much further than previously documented disturbance of bats by SWTs, which appeared fairly localised, and may be due to the importance of linear features specifically for commuting between habitat fragments. If so, the cumulative impacts of such disturbance will be important in areas where suitable foraging and roosting habitats is limited and fragmented, and linear features suitable for commuting between habitat fragments are already rare. These results offer support for recommendations that SWTs should be subject to siting restrictions that create a buffer distance between them and important bat habitats such as linear features. Specifically, this thesis recommends that in landscapes with few alternative commuting routes or where particularly rare bat species are present SWT installations require buffer distances to ensure they are a minimum of 60m away from linear features. There has also been a lack of research into public attitudes towards SWTs, despite local attitudes towards wind farm developments having been linked to planning outcomes, implying attitudes can be a barrier to installations. This thesis presents the results of the first survey of public attitudes specifically towards SWTs. Generally attitudes towards SWTs were positive, with over half of respondents rating SWTs as acceptable across a range of landscape settings. However, as for wind power where public attitudes in general are positive but local wind farm developments may still face opposition, only 35% of respondents were in favour of having a SWT installed in sight of their home. A key finding of this survey was that acceptance of SWTs significantly differed between landscape settings, with those in hedgerows and gardens being less well accepted compared to those on road signs, buildings and fields. Respondent comments highlighted visual impacts, efficient use of technology, noise impacts, wildlife impacts and educational value as important factors in their decisions regarding SWT acceptability. Public concern about wildlife impacts appears to be responsive to context, being important to the lower acceptance of SWTs in hedgerows, which were perceived to be particularly risky for wildlife. Potential SWT owners are also shown to be concerned about wildlife impacts from SWTs. Using a choice experiment methodology, an economics technique that allows valuation of non-market goods, farmers (a group most likely to own SWTs in the UK) were found to be willing-to-pay, through loss of SWT earnings from electricity generation, to avoid disturbance of birds and bats or collision mortality of bats. These findings also support the recommendation of the use of buffer distances for SWTs. Buffer distances between SWTs and linear features will help to alleviate public and SWT owner concerns about wildlife impacts, and also increase public acceptance of SWTs by encouraging their installation away from some of the least accepted landscape settings such as hedgerows. Further, potential SWT owners were also found to have no significant preference for avoiding siting restrictions of SWT installations, suggesting they are open to the use of buffer distances, although the suggested distances were substantially smaller than those this thesis ultimately recommends. The findings presented in this thesis have implications for planning guidance, policy makers and developers, but also raise many questions that will require further study. A list of planning guidance recommendations and a list of recommendations for future SWT research are presented in the final section.
233

Bat species diversity and habitat use assessment with focus on endangered Indiana bats in the Wright State University woods.

Rude, Megan R. 04 September 2019 (has links)
No description available.
234

The social structure, ecology and pathogens of bats in the UK

August, Thomas Adam January 2012 (has links)
This thesis examines the ecology, parasites and pathogens of three insectivorous bat species in Wytham Woods, Oxfordshire; Myotis nattereri (Natterer’s bat), M. daubentonii (Daubenton’s bat) and Plecotus auritus (Brown long-eared bat). The population structure was assessed by monitoring associations between ringed individuals, utilising recent advances in social network analysis. Populations of both M. daubentonii and M. nattereri were found to subdivide into tight-knit social groups roosting within small areas of a continuous woodland (average minimum roost home range of 0.23km2 and 0.17km2 respectively). If this population structure is a general attribute of these species it may make them more sensitive to small scale habitat change than previously thought and has implications for how diseases may spread through the population. M. daubentonii had a strong preference for roosts close to water, away from woodland edge and in areas with an easterly aspect. The factors driving roost choice in M. nattereri and P. auritus remain elusive. The segregation of M. daubentonii into bachelor and nursery colonies was not a result of the exclusion of males from roosts close to water by females, or variation in microclimate preferences between the sexes, as was predicted. Body condition (weight/forearm length) was correlated with host characteristics including age and reproductive status, and weather variables. Astroviruses and Coronaviruses, which have characteristics typical of zoonotic viruses, were identified in UK bat species for the first time. Coronaviruses identified formed species-specific clades while Astroviruses were highly diverse. Though not closely related to human viruses these are potential zoonotic diseases of the future. Models of Coronavirus and ectoparasite distribution suggest individual attributes (e.g. sex and age) and population structure (e.g. the formation of nursery and bachelor colonies) are important predictors of parasite and pathogen prevalence. This study characterises a system that offers many opportunities for future research including studies of sociality, disease modelling and conservation management.
235

ROOSTING BEHAVIOR, HABITAT USE, AND RELATIVE ABUNDANCE OF THE NORTHERN LONG-EARED BAT (<em>MYOTIS SEPTENTRIONALIS</em>) FOLLOWING ARRIVAL OF WHITE-NOSE SYNDROME TO MAMMOTH CAVE NATIONAL PARK

Thalken, Marissa M. 01 January 2017 (has links)
White-Nose Syndrome (WNS; Pseudogymnoascus destructans) is responsible for the regional population collapse of many cave-hibernating bat species, including the northern long-eared bat (Myotis septentrionalis), in eastern United States and Canada. I evaluated roosting behavior, habitat selection, and landscape-scale distribution of roosts of the northern long-eared bat during spring emergence and the early maternity season in Mammoth Cave National Park, Kentucky, USA, from 2015 to 2016. Logistic regression analysis comparing habitat features of roosts with random plots indicated selection of roosts reflected the costs of energetic demands by sex and reproductive status. Relative abundance of local bat species was assessed pre- and post-arrival of WNS in the Park during the summer season, with capture rates observed during the progression of WNS indicating that the fungal disease led to declines in the overall abundance of several bat species on the summer landscape, especially the northern long-eared bat. Distributional trends were quantified using spatial point pattern analysis which indicated that bats had clear roosting patterns associated with landscape level features and habitat resources. Monitoring bat populations regionally and at local scales will be imperative to helping conservation efforts for several bat species most affected by WNS.
236

Parfum de figues : approche évolutive de la communication entre une plante, ses insectes pollinisateurs et ses vertébrés disperseurs / « Parfums de figues » : an evolutionary approach to communication between a plant, its pollinating insects and its vertebrate seed dispersers

Soler, Catherine 03 December 2010 (has links)
Pour l'ensemble des organismes vivants, la communication (intra ou interspécifique) est le véhicule de l'information, un élément central dans l'interaction entre individus. Elle a ainsi des impacts primordiaux sur les traits d'histoire de vie des espèces, et est donc façonnée par la sélection naturelle. Au cours de cette thèse, nous nous sommes intéressés à l'évolution de la médiation chimique, c'est-à-dire à la transmission d'informations par voie chimique entredeux individus, dans les interactions plantes/animaux. Nous avons choisi le modèle figuier et ses partenaires mutualistes, de la guêpe pollinisatrice aux vertébrés disperseurs de graines. La médiation chimique (ici émission de bouquets volatils constitués de terpènes et de dérivés benzéniques et d'acides gras) permet aux figuiers d'assurer leur reproduction, par attraction des pollinisateurs et des disperseurs de graines. Il existe environ 800 espèces de figuiers à travers le monde, à distribution principalement tropicale. Les figuiers, fructifiant toute l'année,sont souvent qualifiés d'espèce clef de voute des écosystèmes tropicaux, car ils assurent ainsi le maintien des populations de frugivores dans les forêts tropicales dans les périodes où très peu d'espèces d'arbres fructifient. L'interaction figuier/disperseur est plutôt généraliste, alors que le mutualisme figuier/pollinisateur, un exemple de nursery pollination, est hautement spécifique et obligatoire. Au cours de cette thèse, nous avons mis en évidence que les contraintes phylogénétiques et géographiques exercées sur la médiation chimique étaient négligeables, alors que les pressions de sélection que représentent les mutualistes sont nettement plus importantes dans l'évolution de cette médiation. Ainsi, sexe et stade phénologique du figuier et identité du partenaire mutualiste sont des informations qui peuvent être portées par la médiation chimique. Notre approche, globale et multidisciplinaire, des interactions entre les figuiers et leurs partenaires mutualistes aux deux phases de dispersions des gènes de la plante, permet une meilleure compréhension de l'évolution de la communication, et montre que les pressions façonnant ce message façonnent l'interaction elle-même. / For all living organisms, communication (intra-or interspecific) is the vehicle of information, anelement central to interactions among individuals. It thus has fundamental impacts on lifehistory traits of species, and is shaped by natural selection. This thesis is concerned with thechemical mediation of communication, i.e., the transmission of information by chemical signals,in the context of animal-plant interactions. We chose as a model system the interactionsbetween figs and their mutualist partners, including both pollinating fig wasps and vertebrateseed dispersers. Chemical mediation (in this case the emission of bouquets of volatilecompounds comprising terpenes, benzenoids and fatty acid derivatives) enables figs to ensuretheir reproduction by attracting pollinators and seed dispersers. There exist about 800 species ofFicus worldwide, principally in tropical regions. Figs, which fruit throughout the year, are oftenconsidered keystone species of tropical ecosystems, because their year-round fruiting maintainspopulations of seed-dispersing frugivores during fruit-poor lean seasons'. Interactions betweenfig species and seed-dispersing animals are generalist' (i.e., broad food species ranges), whilefig/pollinator mutualisms, examples of nursery pollination' systems, are highly species-specificand obligatory. In this thesis, we showed that phylogenetic and geographic constraints actingon chemical mediation are negligible, whereas selection pressures grounded in pollination andseed-dispersal mutualisms play a strong role in shaping the evolution of chemical mediation.Thus, chemical mediation carries information such as the sex and developmental stage of thefig tree, as well as the identity of the mutualistic partner. Our comprehensive, multidisciplinaryapproach to interactions between figs and their mutualist partners in the two phases ofdispersal of the plant's genes leads to an improved understanding of the evolution ofcommunication, and showed that the selective pressures shaping the message are also thoseshaping the interaction itself.
237

Změny středoevropské netopýří fauny na hranici pliocen/pleistocen: rod Myotis / Changes in mid-European bat fauna along the Plio/Pleistocene boundary: denus Myotis

Trávníčková, Eva January 2016 (has links)
This diploma thesis summarizes results of the detailed morphometric analysis of extensive fossil materials of the genus Myotis from the upper Pliocene deposits of Javoříčské caves (Czech Republic) and Urwista cave (Poland). Patterns of phenotype variation of particular fossil populations were analyzed with aid of uni- and multivariation techniques, compared with type series of fossil taxa described from MN15 site Gundersheim and a comparative series of extant European species. Nine fossil and 10 extant species were identified and further reexamined in terms of their phenotype variation and possible phylogenetic relations. The phenotype structure of fossil assemblages were compared to that of Gundersheim and extant European fauna: samples from Urwista cave show clear resemblances to the former one, those from Javoříčské cave exhibit certain similarities to the extant European fauna despite clear differences in variation patterns of particular species. Technical preparation, documentation by photographic material, measurement and statistical analysis is included in this work. Key words: bats, Pliocene, phenotype dynamics, community structure
238

Evaluación descriptiva de la rabia humana y animal, y desarrollo de un modelo predictivo de rabia bovina en el Perú / Descriptive evaluation of human and animal rabies, and development of a predictive model of bovine rabies in Peru

Stanojlovic, Francisco Miroslav Ulloa 21 March 2019 (has links)
La rabia es una enfermedad viral, con una alta tasa de mortalidad, la cual es principalmente transmitida por el perro doméstico y el murciélago hematófago, Desmodus rotundus. A pesar de las acciones de prevención y control aún es endémica en el Perú. Los principales objetivos del presente trabajo fueron la descripción de la rabia humana y animal en el Perú, como también el desarrollo de un modelo predictivo de transmisión del virus de la rabia en el ganado bovino. Se utilizaron los reportes nacionales oficiales de casos y brotes de rabia humana y animal entre los años del 2001 al 2017. Los resultados indicaron que los casos de rabia humana ocurren principalmente como consecuencia del ciclo silvestre, y se presentan con mayor frecuencia en las regiones amazónicas. Mientras que los casos de rabia canina han sufrido un reciente aumento debido al brote de la enfermedad en el sur del Perú. Por otro lado, los focos de la rabia bovina han sido bastantes frecuentes a lo largo de los años, y se encuentran distribuidos especialmente a lo largo de los valles interandinos y regiones amazónicas del Perú. Asimismo, el riesgo de transmisión de rabia de murciélagos hematófagos para bovinos se estimó mediante la adaptación de un modelo de receptividad y vulnerabilidad basado en árboles de decisión, para el desarrollo de un modelo predictivo de rabia bovina por distritos. Los datos oficiales de los brotes de la enfermedad en bovinos y la información sobre alteraciones ambientales se utilizaron como covariables. La densidad de bovinos y las características geomorfológicas de cada distrito fueron obtenidas a través del último censo nacional agropecuario y de los sistemas de información geográfica disponibles. El modelo fue validado a través de la evaluación de algunos escenarios que fueron concebidos a partir de diferentes puntos de corte de las variables de receptividad en comparación con la información de los brotes de los últimos 6 años, a fin de encontrar el grado de predicción más adecuado para la ocurrencia de brotes de rabia por distrito. Entre las principales conclusiones, se encuentra la importancia del mantenimiento de las políticas nacionales de prevención y promoción de la salud de la rabia humana y animal en el Perú. Además, del desarrollo de nuevos criterios de intervención que prioricen la ecología de los transmisores del virus a las poblaciones susceptibles, lo que puede representar una mejor opción que otras medidas preventivas que no han tenido el éxito esperado. Finalmente, el modelo de predicción para la rabia bovina propuesto, a pesar de depender de la información generada por la vigilancia epidemiológica de la enfermedad, representa una herramienta interesante para optimizar su funcionamiento a nivel nacional. / Rabies is a viral disease, with a high mortality rate, that is mainly transmitted by the domestic dogs and the hematophagous bat, Desmodus rotundus. Despite the prevention and control actions, it is still endemic in Peru. The main objectives of the present work were the description of human and animal rabies in Peru, as well as the development of a predictive model of transmission of rabies virus in livestock. The official national reports of cases and outbreaks of human and animal rabies between the years 2001 to 2017 were used. The results indicated that human cases of rabies mainly occur as a consequence of the wild cycle, that are presented with higher frequency in the Amazonian regions. While dog cases of rabies have suffered a recent increase due to the outbreak of the disease in Southern Peru. On the other hand, the outbreaks of bovine rabies were frequent over the years being distributed particularly along the inter-Andean valleys and Amazonian regions of Peru. Additionally, the risk of rabies transmission from hematophagous bats to bovines was estimated through the adaptation of a receptivity and vulnerability model based on decision trees, for the development of a predictive model of bovine rabies by districts. The official data of outbreaks of the disease in bovines and the information on environmental alterations were used as covariates. The density of livestock and the geomorphological characteristics of each district were obtained through the last national livestock census and the geographic information systems available. The model was validated through the evaluation of some scenarios that were conceived from different cut points of the receptivity variables compared to the information of the outbreaks from the last 6 years, in order to find the most suitable degree of prediction for the occurrence of rabies outbreaks by district. Among the main conclusions, is the importance of maintainance of the national policies of prevention and health promotion of human and animal rabiesin Peru. Moreover, the developing of new intervention criteria that prioritize the ecology of the transmitters of the virus to the susceptible populations, which may represent a better option than other preventive measures that havent had the expected success. Finally, the proposed bovine rabies prediction model, despite being dependent on the information generated by the epidemiological surveillance of the disease, represents an interesting tool to optimize its functioning at national level.
239

The use of incidence data to estimate bat (Mammalia: Chiroptera) species richness and taxonomic diversity and distinctness within and between the biomes of South Africa, Lesotho and Swaziland

Seamark, Ernest C.J. 09 January 2014 (has links)
A thesis submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in partial fulfilment of the requirements for the degree of Master of Science. Johannesburg, 2013. / Species richness and estimates of species richness were calculated based on assemblages of bats, within the biomes of South Africa, Lesotho and Swaziland following the vegetation classification of Mucina and Rutherford (2006). Similarity indices were used to explore the various relationships between the assemblages between the various biomes. Taxonomic diversity and distinctness examined the various assemblages within each of the biomes to investigate which biomes contained assemblages that were taxonomically diverse and/or taxonomically distinct compared to all species known to occur within South Africa, Lesotho and Swaziland. The Desert biome had the lowest recorded species richness (5 species), and there was insufficient data to calculate estimates of species richness for this biome. While the Albany had 11 species recorded with species estimates (Est.) ranging between 11-12, then in increasing order - Nama-Karoo (12 species, Est. 13-25 species), Succulent-Karoo (13 species, Est. 15-30 species), Fynbos (17 species, Est. 18-25 species), Indian Ocean Coastal Belt (31 species, Est. 32-36 species), Forest (32 species, Est. 37-46 species), Grassland (39 species, Est. 42-54 species), Azonal (45 species, Est. 49-63 species) and Savanna (57 species, Est. 59-67 species). The mean recorded estimates (based on the averages of all models) and rounding up to a full species indicates that the Albany biome contains the lowest expected species richness of 12 species, then Fynbos and Nama-Karoo (21 species), Succulent-Karoo (22 species), Indian Ocean Coastal Belt (34 species), Forest (43 species), Grassland (49 species), Azonal (54 species) and Savanna (64 species). Sample completeness was calculated for each of the biomes which indicates in ascending order that the Albany biome is 93.2% complete followed by the Indian Ocean Coastal Belt biome (91.1%), Savanna biome (89.9%), Azonal biome (84.1%), Fynbos biome (81.5%), Grassland biome (80.7%), Forest biome (75.8%), Succulent-Karoo biome (61.3%), and Nama-Karoo biome (59.9%). This showed that the Albany biome was found to be the only biome that has been sufficiently sampled. The Jaccard and Sørensen pair wise indices resulted in the clustering of the biomes with similar species richness, due to the large range in species richness (5-57 species) between the biomes. The Lennon et al. (2001) index which is not affected by large species richness between the samples indicated that the Desert and Nama-Karoo assemblages were most dissimilar to one another, while the Indian Ocean Coastal Belt assemblage was the most similar to the remaining biome assemblages. The Albany biome assemblage and Azonal biome assemblage were shown to the most dissimilar to one another. The Grassland, Nama-Karoo and Savanna biomes contribute to higher taxonomic diversity, while the Albany, Azonal, Fynbos, Nama-Karoo and Succulent-Karoo biomes contain lower species richness generally but represent a higher taxonomic distinctness from the chiroptera assemblages in the Grassland and Savanna biomes. The Desert, Forest and Indian Ocean Coastal Belt biomes do not iv contain bat assemblages that are neither taxonomically distinct nor diverse when compared to the taxa of South Africa, Lesotho and Swaziland. The bat assemblage within the Nama-Karoo are both taxonomically diverse and distinct from chiroptera assemblages found within the other nine biomes, requiring a greater focus on conservation actions for the bat species assemblage located within this biome.
240

A estrutura populacional da quiropterofauna em sub-bosque florestal: o uso da amostragem sistemática / Bats population structure in understory forest: use of systematic sampling

Lazo, Lizie Jatkoske 21 September 2011 (has links)
Os métodos de amostragem por conveniência procuram maximizar o volume das amostras e podem, neste sentido, ser bastante eficazes, porém, o esperado é que venham a comprometer a acurácia e a precisão na representação de espécies em sub-bosque floretal. Isto se deve ao fato dos pesquisadores, usualmente, alocarem as redes-neblina em locais conhecidos por atrair uma maior abundância de animais e onde estes apresentariam uma redução em sua habilidade para detectar e se esquivar à rede-neblina, como em rotas de voo, fontes alimentares e abrigos. A alocação determinística das redes pode, desta forma, resultar em um elevado viés amostral, caracterizado pela superamostragem de algumas espécies que, frequentemente, utilizam estes espaços, em detrimento daquelas que, ao contrário, estariam sendo sub-representadas por não os utilizarem na mesma proporção. Baseado nisto, este estudo teve por principal objetivo o desenvolvimento de método padronizado, que pudesse elevar a acurácia e a precisão na obtenção de dados populacionais de quirópteros em sub-bosque florestal, com foco na amostragem sistemática. Como procedimentos metodológicos, uma área amostral de 8,82 ha foi delimitada em três fragmentos florestais, no interior do estado de São Paulo, dos tipos vegetacionais cerradão (22º15\'S e 47º39\'W), floresta estacional semidecidual (22º09\'S e 47º33\'W) e eucalipto (22º11\'S e 47º39\'W), para o que um conjunto móvel de doze redes-neblina foi utilizado na captura e recaptura dos quirópteros, no período de jul/2009 a jun/2010, totalizando um esforço amostral de 155.520 h.m2. A taxa de detecção das redes-neblina foi estimada, através de observações em tempo real, e utilizada na correção das estimativas populacionais. A habilidade de detecção e esquiva à captura foi elevada, porém, não diferiu do observado nas rotas de voo, anteriormente demonstrado por estudos comportamentais. O resultado disto foi o registro de quatorze espécies e, pela correção das estimativas, Desmodus rotundus foi a dominante na região e no eucalipto, enquanto que Micronycteris microtis foi a espécie mais abundante no cerradão e, Glossophaga soricina, na floresta estacional semidecidual. A abundância da Carollia perspicillata não foi corrigida, devido a sua elevada taxa de recaptura atribuída à redução na habilidade para detectar as redes, levando a uma redução de sua importância, dentre as espécies dominantes, na região e nos fragmentos de vegetação nativa. De forma inovadora, foi possível estimar o índice de densidade e o padrão de distribuição populacionais, e, ainda, dada a padronização espacial, compreender a influência de aspectos como a altitude e a declividade do solo, a densidade da vegetação, a presença e a altura do dossel florestal, sobre as populações de quirópteros. Assim, foi concluído que a amostragem sistemática pode ser mais acurada e precisa para os estudos populacionais por reduzir os vieses amostrais dos métodos de amostragem por conveniência, aumentar nossa compreenção sobre os parâmetros populacionais e a forma com que os quirópteros interagem com o ecossistema florestal, e potencializar a comparação de dados em diferentes situações e localidades. / Bats population convenience sampling methods mostly focus on maximizing sample volumes. This method can be highly effective in delivering significant number of samples, but on the other hand can potentially compromise accuracy and precision in representation of species potentially available in understory forests. This is due to the fact that researchers tend to position mist-nets according to known places by attracting greater abundance of bats and where its might be less attentive to the presence of mist-nets, such as bats flyways, food sources and shelters. However, the deterministic approach for mist-nets placement allocation may lead to a misrepresentation of the species in specific habitats and result in oversampling of the species that usually occur in those places. Based on this, the key objective of this study was to develop an standardized protocol that enhances accuracy and precision when collecting bat samples in understory forest, with focus on the evaluation of the systematic sampling. An sample area of 8.82 ha was delimited in three forest fragments within São Paulo State. These were of the vegetation types of cerradao (22º15\'S to 47º39\'W), semideciduous florest (22º09\'S to 47º33\'W) and forestation of eucalyptus (22º11\'S to 47º39\'W). A mobile set of twelve mist-nets was used to capture and recapture of bats from the Jul/2009 to Jun/2010, totaling a sampling effort of 155,520 h.m2. The detectation rate of mist-net of bats was estimated by observations in real time and was used to obtain correct population estimates. The ability of bats to detect and evade capture was hight, but consistent with observed for the flyways, earlier demonstrated by behavioral studies. The result of this was fourteen species recorded in the understory of the different forest fragments, and through the correctness of the estimates, the Desmodus rotundus was dominant in the region and in eucalyptus, while Micronycteris microtis was the most abundant specie in the cerradao and Glossophaga soricina in the semideciduous forest. The abundance of the Carollia perspicillata has not been corrected, due to its hight rate of recapture what was possibly the result of a reduced ability to detect the mist-net, leading to a reduction in your importance amoung the dominant species in the region and fragments of native vegetation. The proposed systematic design innovated and led to enhanced accuracy and precision, beyond to enable the estimate density level and the population distribution patterns. Thus, the spatial standardization in allocation mist-nets provides far representation of the influence of all habitat conditions on the bat populations, such as altitude and slope soil, vegetation density, presence and height of the forest canopy. Therefore, the overall conclusion was that the systematic sampling can be more accurate and precise for bats population studies by reduce convenience sampling methods biases, increase the understanding bats interaction with the forest ecosystem and the potentiate data comparation in different situations and localizations.

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