Made available in DSpace on 2014-12-17T14:33:09Z (GMT). No. of bitstreams: 1 KarolLBOF_DISSERT_PARCIAL.pdf: 340660 bytes, checksum: f2a188d52831a6a40d06910a31049e94 (MD5) Previous issue date: 2012-07-05 / How ecologically similar species are able to coexist has always generated great interest in the scientific community. Classical niche theory predicts that species coexistence is only possible when they segregate in at least one dimension of the ecological niche, thus leading to ecological differentiation among species. However, recent work has shown that species that are more similar in some ecological traits are the ones more prone to be able to coexist (environmental filter). The knowledge of how these forces act shaping ecological communities can reveal co-existence strategies, providing important information for management and conservation of the species. This study tested these hypotheses using a pair of coexisting species of Herpsilochmus, H. pectoralis and H. sellowi. In this study I use high resolution (50 x 50 m) ecological niche models to Identify which environmental factors best predict species occurrence. Next, I calculate the overlap in habitat use by species and build null models to test the hypothesis of spatial niche segregation. In addition, I obtain the selectivity parameters of habitat use to test whether the species H. pectoralis (larger body size) is less selective than H. sellowi (smaller body size) as stated in the literature for other species. The results reject the ecological equivalence among species, revealing that the species of Herpsilochmus explore the habitat differently, having different environmental niches. The hypothesis of environmental filter was not observed in my analysis, the observed overlap in habitat use among species was lower than expected by chance. Evidence that Herpsilochmus are spatially segregating reinforces the hypothesis of interspecific competition as the predominant force in the selection of microhabitat of the species. However, more data and experiments are necessary to state categorically that the observed pattern is a result of current or past competition / Como esp?cies similares ecologicamente s?o capazes de coexistir sempre gerou grande interesse na comunidade cient?fica. A teoria cl?ssica de nicho prev? que para que a coexist?ncia seja poss?vel as esp?cies devem segregar em alguma dimens?o do nicho ecol?gico, portanto levando a diferencia??o entre as esp?cies. No entanto, trabalhos recentes tem demonstrado que justamente esp?cies mais similares em algumas caracter?sticas ecol?gicas seriam mais capazes de coexistir (filtro ambiental). O conhecimento de como essas for?as atuam nas comunidades pode revelar estrat?gias de coexist?ncia, trazendo importantes informa??es para o manejo e conserva??o das esp?cies. Neste estudo testei essas hip?teses de coexist?ncia utilizando o par de esp?cies Herpsilochmus pectoralis e H. sellowi. Para isso utilizei modelos de nicho ecol?gico em alta resolu??o (50 x50 m).Identifiquei quais os fatores ambientais estudados melhor predizem a ocorr?ncia das esp?cies. Em seguida, calculei a sobreposi??o no uso de h?bitat pelas esp?cies e constru? modelos nulos para testar a hip?tese de segrega??o de nicho espacial. Ainda, calculei par?metros de seletividade do uso do h?bitat para testar se a esp?cie H. pectoralis (esp?cie de maior tamanho de corpo) ? menos seletiva que o H. sellowi (esp?cie de menor tamanho de corpo) como previsto na literatura para outras esp?cies.Os resultados rejeitam a equival?ncia ecol?gica entre as esp?cies, revelando que as esp?cies de Herpsilochmus exploram o habitat de forma diferenciada, possuindo nichos ambientais distintos. A hip?tese de filtro ambiental n?o foi evidenciada em nossas an?lises, sendo a sobreposi??o no uso do h?bitat observada entre as esp?cies menor do que o esperado ao acaso. Evid?ncias de que os Herpsilochmus est?o segregando espacialmente refor?a a hip?tese da competi??o interespec?fica como for?a predominante na sele??o de microh?bitat das esp?cies. No entanto, para afirmar categoricamente que o padr?o observado ? efeito de uma competi??o atual ou passada experimentos futuros s?o sugeridos

Les modèles de distribution d’espèces ont été identifiées comme pertinents pour cartographier et caractériser la qualitéd’habitat des moustiques vecteurs du paludisme, Anopheles, afin de participer à l’estimation du risque de transmission decette maladie et à la définition de stratégies de lutte anti-vectorielle ciblées. La transmission du paludisme dépend de laprésence et de la distribution des vecteurs, qui dépendent elles-mêmes des conditions environnementales définissant laqualité des habitats écologiques des Anopheles. Cependant, dans certaines régions, les données de captures d’Anophelessont rares, et rend difficile la cartographie de leurs habitats. De plus, le recueil de ces données est très souvent soumis à desbiais d’échantillonnage.Cette thèse fournit une solution à la cartographie des vecteurs du paludisme, en considérant deux aspects très peu étudiésdans la modélisation : le faible nombre de sites de présence disponibles et l’existence d’un biais d’échantillonnage. Uneméthode originale de correction de l’effet du biais d’échantillonnage est proposée puis appliquée à des données de présencedu principal vecteur du paludisme en Guyane, Anopheles darlingi. Un modèle de distribution d’An. darlingi a ensuite étéconstruit, permettant d’obtenir une carte de qualité d’habitat en cohérence avec la connaissance des entomologistes etfournissant des performances de prédiction élevées. La méthode de correction proposée a ensuite été comparée auxméthodes existantes dans un contexte applicatif caractérisé par la rareté des données d’occurrence de l’espèce et laprésence d’un biais d’échantillonnage. Les résultats montrent que la méthode développée est adaptée aux cas où le nombrede sites de présence est faible. Cette thèse contribue, d’une part, à combler les lacunes théoriques et d’applicabilité desméthodes actuelles visant à corriger l’effet des biais d’échantillonnage et, d’autre part, à compléter la connaissance sur ladistribution spatiale et la bioécologie du principal vecteur du paludisme en Guyane française. / Species distribution models are identified as relevant to map and characterize the habitat quality of Anopheles genusmosquitoes, transmitting malaria, and thus to both participate in the estimation of the transmission risk of this disease and inthe definition of targeted vector control actions. The malaria transmission depends on the presence and distribution of thevectors, which are themselves dependent on the environmental conditions that define the quality of the ecological habitats of the Anopheles. However, in some areas, Anopheles collection data remain scarce, making it difficult to model these habitats. In addition, the collection of these data is very often subjected to significant sampling biases, due, in particular, to unequal accessibility to the entire study area. This thesis provides a solution to the mapping of malaria vectors, considering two very few studied aspects in modeling: the low number of available presence sites and the existence of a sampling bias. An original method for correcting the effect of the sampling bias is proposed and then applied to presence data of Anopheles darlingi species - the main vector of malaria in South America - in French Guiana. Then, a distribution model of An. darlingi was built to obtain a map of habitat quality consistent with entomologists’ knowledge and providing high prediction performances. The proposed correction method was then compared to existing methods in an application context characterized by the scarcity of the species occurence data and the presence of a sampling bias. The results show that the developed method is adapted to cases where the number of sites of presence is low. This thesis contributes, on the one hand, to fill theoretical and applicability lacuna of current methods intended to correct the effect of the sampling bias and, on the other hand, to supplement the knowledge on both the spatial distribution and the bio-ecology of the main malaria vector in French Guiana.

Studies of the occurrence of montane and boreomontane species in ravines of the sandstone landscape are scarce and the occurrence of these species are explained by the presence of temperature inversion. The question is, which factors limit the occurrence ofthese species in ravines with temperature inversion. The aim of this diploma thesis is to reveal factors that influence the occurrence of Huperzia selago in inverse ravines of sandstone landscape. This work uses a habitat variables recorded directly for populations of H. selago and variables derived from a digital elevation model. These derived variables are also used for creation of two predictive models of geographic distribution of H. selago in the National Park Bohemian Switzerland. When we summarize the most informative variables of predictive models and habitat conditions significantly different from control sites, we get the typical habitat of H. selago. Such sites will likely be found on the rock at the bottom of the valley. Factors that influence the suitability of habitat are: moisture, vegetation type, slope, and distance to the bottom of the valley.

All species of orchids are sensitive plants and records of their distribution are rare. Their rarity is related to their complex biology and their sensitivity to changes in the environment. It is necessary to pay attention to these threatened species, so that we could preserve them from extinction. For their effective protection we need to know the main causes of extinction of their localities. It is also useful to know the factors, which determine their distribution, so that we could find new localities, where they occur. In this thesis I analyzed some climatic, geographic and ecological factors in the Jeseníky mountains and their surroundings. First, I visited localities of orchids, which were registered in large databases of their presence in the past. The four most numerous species were analyzed using the program MaxEnt. Based on the revisions, existence of 2/3 of the revised localities was confirmed, 8% of the revised localities became extinct because of overgrowth or due to human intervention in the landscape. From the MaxEnt results it is clear, that for all species the most important factor at the 50 × 50 m scale, is the type of biotope and heterogeneity of the countryside. The most suitable biotopes are floodplain and wetland forests, mesophile meadows, natural scrubs, peat bogs and...

Submitted by Jadson Francisco de Jesus SILVA (jadson@uefs.br) on 2018-02-21T21:35:29Z No. of bitstreams: 1 Disserta??o Pos banca Final.pdf: 10846078 bytes, checksum: 3a74cdd39783b17cdb4b6e3cc625186c (MD5) / Made available in DSpace on 2018-02-21T21:35:29Z (GMT). No. of bitstreams: 1 Disserta??o Pos banca Final.pdf: 10846078 bytes, checksum: 3a74cdd39783b17cdb4b6e3cc625186c (MD5) Previous issue date: 2017-09-29 / Funda??o de Amparo ? Pesquisa do Estado da Bahia - FAPEB / The genus Anomochloa Brongn. includes a single species, A. marantoidea Brongn., known as the earliest extant grass. It is a rare species from the Brazilian Atlantic rainforest, endemic to the southern Bahia. Only two populations were discovered so far, occurring out protected areas with few individuals registered, thus, A. marantoidea is considered critically threatened with extinction. The study of this species is highly important to understand evolutionary processes within Poaceae family. The present study aimed to increase the knowledge about its geographic range, to evaluate its potential areas of occurrence and to access its genetic diversity, detecting probable genetic threats as a result of its small population size. These data are essential for the development of conservation programs. Two new populations were recently discovered and the modeled ecological niche to A. marantoidea did not diverge from the expected geographical extent, denoting high climatic restriction and reasserting its rarity. The variables Index of Tree Cover and Rainfall are the main components that influence its restricted distribution. The levels of genetic diversity within the populations accessed by molecular markers indicate that A. marantoidea exhibits capacity for favorable response in short time and a conservation plan may be efficient to maintain its current genetic diversity. This diversity is correlated to the population size, for this reason, the propagules necessary for establishing new populations in climatically suitable sites must be originated from the largest populations. Genetic structure analysis suggests recent fragmentation and low gene flow among populations showing high levels of inbreeding. In this way, we recommend human mediated gene flow between the populations in order to mitigate the risks of inbreeding depression. It is hypothesized that the genetic differences among populations are caused mostly by random drift, resulting in populations with few individuals more genetically differentiated than the large ones. This implies that a minimum number of individuals (~100) is desirable to avoid the decrease of genetic diversity in populations. / O g?nero Anomochloa Brongn. inclui uma ?nica esp?cie, A. marantoidea Brongn., reconhecidamente a mais antiga entre as gram?neas viventes. ? uma esp?cie rara, end?mica da Mata Atl?ntica do sul do estado da Bahia com apenas duas popula??es conhecidas at? pouco tempo, ambas com poucos indiv?duos e nenhuma em ?rea protegida, sendo considerada criticamente amea?ada de extin??o. O conhecimento sobre essa esp?cie ? de suma import?ncia para compreender a evolu??o dentro da fam?lia, e assim, o presente trabalho visou ampliar o conhecimento acerca da extens?o da distribui??o geogr?fica da mesma e avaliar suas ?reas potenciais de ocorr?ncia, bem como conhecer os n?veis de diversidade e amea?as gen?ticas resultantes do pequeno tamanho populacional, dados essenciais para programas que visem sua conserva??o. Duas novas popula??es foram localizadas recentemente e o nicho ecol?gico modelado n?o divergiu da distribui??o esperada, indicando uma alta restri??o clim?tica e reafirmando a raridade da esp?cie. O ?ndice de cobertura vegetal e a precipita??o foram os principais requisitos ambientais a influenciar sua distribui??o t?o restrita. Os n?veis de diversidade gen?tica nas popula??es inferidos por marcadores moleculares indicam que a esp?cie tem capacidade para responder imediatamente bem em curto prazo e que um plano de conserva??o pode ser eficiente em manter a atual diversidade espec?fica. Esta diversidade se mostrou relacionada com tamanho populacional, assim, prop?gulos para o estabelecimento de novas popula??es em s?tios climaticamente adequados devem ser obtidos das maiores popula??es. An?lises de estrutura??o gen?tica sugerem fragmenta??o recente e indicam baixo fluxo g?nico entre as popula??es conhecidas da esp?cie, com consequentes altos n?veis de endogamia, por isso ? recomendado fluxo g?nico mediado por atividade humana entre as popula??es para evitar depress?o endog?mica. ? hipotetizado que diferen?as gen?ticas entre as popula??es s?o causadas majoritariamente por deriva aleat?ria, o que tornou popula??es com menos indiv?duos mais diferenciadas geneticamente daquela com o maior n?mero. Isso implica que um n?mero m?nimo de indiv?duos (~100) ? desej?vel para evitar redu??o na diversidade gen?tica das popula??es.

The well-known symbol for conservation, the giant panda bear, and the original red panda have been forced into remote habitats due to anthropogenic disturbance, making ecological study difficult. Therefore the first known species distribution model was created to predict the most likely areas of occurrence within the known range of these elusive animals. These models were then projected onto North America and evaluated against existing breeding programs. Additionally, the close proximity of the Gray Fossil Site and the discovery of the most complete fossil red panda specimens in the world allowed ecomorphological comparisons between the modern red panda, Ailurus fulgens and the fossil red panda, Pristinailurus bristoli. Spatial data and morphometric results from this study will aid conservation work and breeding programs globally.

No description available.

The hemlock woolly adelgid, an invasive non-native insect, is threatening eastern hemlock in Kentucky. This study examined three techniques to map the distribution of eastern hemlock using decision trees, remote sensing, and species distribution modeling. Accuracy assessments showed that eastern hemlock was best modeled using a decision tree without incorporating satellite radiance. Using the distribution from the optimal model, risk maps for susceptibility to hemlock woolly adelgid infestation were created using two species distribution models. Environmental variables related to dispersal were used to build the models and their contributions to the models assessed. The models showed similar spatial distributions of eastern hemlock at high risk of infestation.

Little is known about the distribution of black corals in the northwestern Gulf of Mexico. Of thirty-nine species of black coral documented in the Western Atlantic, thirty have been previously documented by various studies in the Gulf of Mexico. This study proposes potential range extensions for four black coral species, including Stichopathes gracilis, Stichopathes semiglabra, Tanacetipathes paula, and Tanacetipathes spinescens, to include the Gulf of Mexico. The validation of in situ identifications of black coral species is evaluated, and recommendations for species identifications and species groupings are made. Black coral associated fauna are documented, supporting known associations and documenting potentially new associations and species. Habitat suitability models for the distribution of black coral species at selected banks in the northwestern Gulf of Mexico were generated. Presence-only models made using the MaxEnt modeling program were compared to presence-absence models made using Boosted Regression Tree modeling techniques. Presence-absence models were documented to have greater predictive accuracy than the presence-only models, which showed evidence of model overfitting. The model was projected to five similar salt-dome features in the region, highlighting extensive habitat for multiple black coral species in these unexplored habitats. This study presents habitat suitability maps as a testable hypothesis for black coral distribution in the mesophotic zone of this region.

Aim MaxEnt, a very popular species distribution modelling technique, has been used extensively to relate species’ geographic distributions to environmental variables and to predict changes in species’ distributions in response to environmental change. Here, we test its predictive ability through time (rather than through space, as is commonly done) by modeling colonizations and extinctions. Location Continental U.S. and southern Canada. Time period 1979-2009 Major taxa studied Twenty-one species of passerine birds. Methods We used MaxEnt to relate species’ geographic distributions to the variation in environmental conditions across North America. We then modelled site-specific colonizations and extinctions between 1979 and 2009 as functions of MaxEnt-estimated previous habitat suitability and inter- annual change in habitat suitability and neighborhood occupancy. We evaluated whether the effects were in the expected direction, we partitioned model’s explained deviance, and we compared colonization and extinction model’s accuracy to MaxEnt’s AUC. Results IV Colonization and extinction probabilities both varied as functions of previous habitat suitability, change in habitat suitability, and neighborhood occupancy, in the expected direction. Change in habitat suitability explained very little deviance compared to other predictors. Neighborhood occupancy accounted for more explained deviance in colonization models than in extinction models. MaxEnt AUC correlates with extinction models’ predictive ability, but not with that of colonization models. Main conclusions MaxEnt appears to sometime capture a real effect of the environment on species’ distributions since a statistical effect of habitat suitability is detected through both time and space. However, change in habitat suitability (which is much smaller through time than through space) is a poor predictor of change in occupancy. Over short time scales, proximity of sites occupied by conspecifics predicts changes in occupancy just as well as MaxEnt. The ability of MaxEnt models to predict spatial variation in occupancy (as measured by AUC) gives little indication of transferability through time. Thus, the predictive value of species distribution models may be overestimated when evaluated through space only. Future prediction of species’ responses to climate change should make a distinction between colonization and extinction, recognizing that the two processes are not equally well predicted by SDMs.