O lagarto Tropidurus torquatus (Wied, 1820) possui ampla distribuição geográfica e é encontrado em abundância nas áreas onde ocorre, sendo considerada uma espécie apropriada para estudos ecológicos. No presente estudo nós analisamos o período de atividade, o uso do microhabitat, a intensidade de forrageamento, a dieta e a ecologia térmica de uma população de T. torquatus do Costão de Itacoatiara, no Parque Estadual da Serra da Tiririca, situado nos municípios de Niterói e Maricá, RJ. Os dados foram coletados em dois períodos: entre julho de 2004 e janeiro de 2008 para estudo do período de atividade, uso do microhabitat e intensidade de forrageamento, e entre julho e agosto de 2010 para estudo da ecologia térmica e dieta. Todos os indivíduos coletados eram adultos, com comprimento rostro-cloacal médio de 66,2 12,0mm para machos (n = 11) e 64,1 8,0mm para fêmeas (n = 03). O período de atividade de T. torquatus no Costão de Itacoatiara durou de 12 a 14 horas. Teve um padrão unimodal na estação seca, com pico de atividade entre 09:00h e 13:00h, durante as horas mais quentes do dia. Na estação chuvosa o padrão de atividade foi bimodal, com um pico entre 8:00h e 9:00h e outro entre 16:00h e 17:00h, ambos associados aos horários de temperaturas ambientais mais amenas. O período de atividade não diferiu entre as estações, o que pode ser explicado pelo extenso pico de atividade dos lagartos na estação seca. Os microhabitats mais utilizados foram o substrato rochoso do Costão e a bromélia, refletindo a disponibilidade destes na área. A intensidade de forrageamento não diferiu sazonalmente e o tempo médio que os lagartos ficaram parados foi maior do que o tempo médio em deslocamento. A dieta foi onívora e esteve composta por artrópodes, principalmente insetos, e material vegetal, principalmente frutos. Os principais insetos consumidos foram Formicidae, Coleoptera e Hymenoptera não-Formicidae como pequenas vespas e abelhas. Os frutos, as sementes e as flores consumidos pertenciam às cactáceas Rhipsalis cereoides e Coleocephalocereus fluminensis, para as quais T. torquatus pode ser um potencial agente dispersor de sementes na área. Lagartos maiores consumiram itens maiores, mas em menor número, indicando um balanço energético positivo. O consumo de material vegetal variou de acordo com o tamanho dos lagartos, aumentando sua proporção nos indivíduos mais velhos. A temperatura média em atividade de T. torquatus foi de 34,3 2,5C, estando na faixa de temperatura corpórea média encontrada para outras populações e para outros Tropidurus. O substrato foi a fonte de calor ambiental com maior importância relativa para a termorregulação dos lagartos durante a estação seca, explicando cerca de 48% da variação na temperatura corpórea da população. Os lagartos termorregularam de forma passiva, principalmente em relação à temperatura do substrato. / The lizard Tropidurus torquatus (Wied, 1820) has a wide geographical distribution and is abundant within its area of occurrence, thus making it a suitable species for ecological studies. In the present study we analysed the activity period, microhabitat use, foraging intensity, diet and thermal ecology of a T. torquatus population in Costão de Itacoatiara, State Park of Serra da Tiririca, situated in the municipalities of Niterói and Maricá, RJ. Data were collected in two steps: between July 2004 and January 2008 for the activity period, microhabitat use and foraging intensity studies and between July and August 2010 for diet and thermal ecology studies. All specimens collected were adults, with snout-vent length = 66,2 12,0mm for males (n = 11) and 64,1 8,0mm for females (n = 3). The activity period of T. torquatus in Costão de Itacoatiara was between 12 and 14 hours. In the dry season it had a unimodal pattern, with a peak between 09:00 and 13:00h, during the hottest hours of the day. In the rainy season the pattern was bimodal, with a peak between 8:00 and 9:00h and another between 16:00 and 17:00h. Both periods were associated with lower temperatures. There was no significant difference in activity period between seasons, which can be explained by the intense lizard activity period in dry season. The most used microhabitats were rock and bromeliads, which reflects the wide availability of these microhabitats in the study area. Foraging intensity showed no seasonal differences and the mean time that lizards were stationary was higher than the mean time lizards were moving. Diet was omnivorous and composed of arthropods, mainly insects, and vegetable matter, mainly fruits. The most consumed insects were Formicidae, Coleoptera, and other Hymenoptera such as small wasps and bees. Fruits, seeds and flowers consumed belonged to the Cactaceae Rhipsalis cereoides and Coleocephalocereus fluminensis, for which T. torquatus seems to be a potential seed dispersor. Larger lizards consumed larger items, but in smaller numbers, indicating a positive energetic balance. The consumption of vegetable matter varied with lizard size, increasing its proportion in older individuals. The mean activity temperature was 34.3 2.5C, which was inside the range of mean temperature registered for other populations and Tropidurus species. Substrate was the most important environmental heat source for lizard thermoregulation along the dry season, explaining about 48% of the variation in lizard body temperature. The T. torquatus population was predominantly thermoconformer, mainly in relation to the substrate temperature.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The macro and microhabitat use by small-mammal was investigated in an Atlantic Forest- Pampa mosaic. A grid with 88 traps was used, being 27 installed in the understory every two traps placed on the ground, which were 70 m apart of each other. The fieldwork was carried out in 17 monthly phases, during five days, from June 2011 to October 2012, totalizing a sampling effort of 7480 trap-nights. An analysis of variance was used to verify differences in richness, total abundance and abundance of each species among grassland, edges and forest. The same analysis was performed to test if the body mass of each species differs between the vegetation types. Eleven environmental variables measured were summarized through a principal component analysis (PCA). Subsequently, a multiple linear regression analysis was performed between richness and total abundance of each species and the first two axes of PCA. The environmental variables were also correlated to the abundance of small mammal through an analysis of redundancy (RDA). Analysis of variance showed no difference in total abundance and richness for any vegetation types. However, abundance of Oligoryzomys nigripes differed significantly (Q = 1.88, P = 0.0009), being higher in grassland. Considering body mass, there was a significant difference for Akodon montensis (Q = 1824, P = 0.046) and O. nigripes (Q = 1262.1, P = 0.001). The first axis of the PCA, were associated Didelphis albiventris and O. nigripes (r = 0.06, P = 0.022, r = 006, P = 0.018, respectively), and related to variables that characterize forest environments (higher density of woody vegetation). Analysis of variance showed that environmental complexity is not the main factor influencing the richness and abundance of species in the studied area, but there were differences in the pattern of individual distribution according to age, since adults selected best environments than young. The PCA and RDA showed significant effect of microhabitat variables on species occurrence. The presence of A. montesis was influenced by zoochorous dispersion and number of epiphytes, while D. albiventris and O. nigripes were related to forested environments, with greater trees abundance, DAP and litter. The last ones were also correlated with open environments, being D. albiventris related to ferns and distance of water and O. nigripes related to grasses. / A distribuição macro e micro-espacial de pequenos mamíferos não-voadores em uma área de mosaico entre Floresta Atlântica e Pampa foi investigada. Foi utilizada uma grade com 88 armadilhas, 27 foram instaladas no sub-bosque a cada duas armadilhas instaladas no solo, as quais distavam 70 m uma da outra. Foram realizadas 17 fases mensais de campo, durante cinco dias, de junho de 2011 a outubro de 2012, totalizando um esforço amostral de 7480 armadilhas-noite. Uma análise de variância (ANOVA) foi utilizada para verificar se existem diferenças na riqueza, abundância total e abundância de cada espécie entre as fitofisionomias de campo, borda e interior de floresta. Também foi testada a existência de diferenças na massa corporal dos indivíduos para cada espécie, entre essas fitofisionomias. Onze variáveis ambientais mensuradas foram resumidas através de uma análise de componentes principais (PCA). Posteriormente, foi realizada uma análise de regressão linear múltipla entre a riqueza e a abundância total e de cada espécie e os dois primeiros eixos do PCA. As variáveis ambientais brutas foram relacionadas com a abundância de mamíferos por meio de uma análise de redundância (RDA). A análise de variância não mostrou diferença na riqueza e abundância total das espécies para nenhuma das fitofisionomias. Oligoryzomys nigripes foi mais abundante na fitofisionomia de campo (Q = 1,88, P = 0,0009). Quanto à massa corporal, houve diferença significativa para Akodon montensis (Q = 1824, P = 0,046) e O. nigripes (Q = 1262,1, P = 0,001). O primeiro eixo da PCA, associado com Didelphis albiventris e O. nigripes estiveram associadas (r = 0,06; P = 0,022; r = 006; P = 0,018, respectivamente), foi relacionado às variáveis que caracterizam ambientes florestais. A análise de variância mostrou que a complexidade ambiental não é o principal fator que influencia a riqueza e a abundância das espécies na área estuda, porém houve diferenças no padrão de distribuição dos indivíduos conforme a idade, com indivíduos adultos selecionando ambientes distintos dos jovens. A RDA mostrou que a abundância de A. montesis foi influenciada pela dispersão zoocórica e número de epífitas, já D. albiventris e O. nigripes foram relacionados a ambientes florestados, com maior número de árvores, DAP e folhiço. Esses últimos foram correlacionados também a ambientes campestres, com D. albiventris se relacionando a locais com presença de samambaias e distantes da água e O. nigripes a ambientes com alta abundância de gramíneas.

Les microhabitats portés par les arbres (dendro‐microhabitats), comme les cavités, sont nombreux dans les forêts naturelles. Une revue de la littérature a révélé qu'ils sont des ressources d'habitat évolutives, temporaires, et déterminantes pour la bio‐complexité des écosystèmes forestiers. Leur étude est cependant récente et les connaissances sont par conséquent fragmentaires. En forêt exploitée, les dendro‐microhabitats sont des objets sylvicoles simples et bien catégorisés, souvent comme des défauts de l'arbre dévaluant sa valeur commerciale. Comment concilier alors le maintien d'objets écologiques cruciaux et les objectifs économiques de production de bois de haute qualité marchande ? Ce travail de thèse avait comme objectifs d'une part de contribuer à une meilleure qualification du rôle écologique des dendro‐microhabitats pour la biodiversité et, d'autre part, de fournir des éléments de réponse pratiques aux gestionnaires d'espaces forestiers soucieux d'intégrer la conservation d'une diversité d'espèces dans leur gestion courante. Il a nécessité la mise en place de 1028 placettes dans 210 forêts françaises dans lesquelles nous avons observé environ 55 000 arbres. Nous avons étudié les relations entre les dendromicrohabitats et la richesse et la composition spécifiques de neuf taxons. Dans le cadre de l'analyse des caractéristiques‐clés de l'arbre et du peuplement pour les dendro‐microhabitats, nous avons montré que l'association des variables essence et diamètre explique respectivement 26 % et 31 % de la variance de l'occurrence des dendro‐microhabitats et de leur diversité dans les hêtraies‐sapinières inexploitées depuis plus de 100 ans. Nous avons défini des seuils de diamètre significatifs pour l'occurrence et la diversité des dendro‐microhabitats portés par le Hêtre (Fagus sylvatica L.) et le Sapin pectiné (Abies alba Mill.). D'autre part, la densité de dendro‐microhabitats et le volume de bois mort ainsi que leurs diversités respectives sont relativement constants tout au long du cycle sylvigénétique des forêts mixtes de montagne. Les feuillus secondaires jouent un rôle crucial dans la régulation de ces stocks en les complétant dans les phases où les dryades fournissent peu de dendro‐microhabitats et de bois mort. Un minimum de 10 hectares est nécessaire pour observer toute la diversité des dendro‐microhabitats. Dans les forêts exploitées, nous avons observé des patrons d'occurrence des dendro‐microhabitats drastiquement différents de ceux observés dans les forêts inexploitées depuis plus d'un siècle : les dendro‐microhabitats y sont toujours moins diversifiés et la densité relative de chaque type est modifiée. Après arrêt de l'exploitation, la reconstitution des stocks de dendro‐microhabitats est lente dans les forêts feuillues de plaine. Un arrêt de l'exploitation pendant 30 années est insuffisant pour observer une reconstitution du stock de dendro‐microhabitats dans tous les contextes et pour changer significativement les communautés de Coléoptères saproxyliques. En mesurant la contribution des dendro‐microhabitats à la biodiversité, nous avons observé que la densité d'arbres porteurs de cavités et de sporophores de champignons lignivores est une variable structurante pour la composition des assemblages et la richesse spécifique des Coléoptères saproxyliques. La densité d'arbres porteurs de dendro‐microhabitats et d'arbres porteurs spécifiquement de bois dur sans écorce ou de sporophore de polypores est significativement corrélée à la richesse spécifique des polypores. Le degré d'ouverture du peuplement ou les conditions climatiques locales affectent, dans certains cas, ces relations. Afin d'harmoniser les futurs protocoles de recherche sur les dendro‐microhabitats et de faciliter le partage des données, nous avons proposé une typologie hiérarchique de référence des dendro‐microhabitats. / Tree microhabitats, such as cavities, are diverse and abundant in natural forests. A literature review revealed that they are dynamic and temporary key habitat resources for the complexity of forest ecosystems. However, since their study is recent, they are still poorly known. In harvested forest, tree microhabitats are well categorized as silvicultural items, mostly as wood defaults decreasing its commercial value. Therefore, how to reconcile the retention of ecological objects crucial for biodiversity and the production of high‐quality timber? This PhD thesis aimed, on the one hand, at participating to better qualify the ecological roles of tree microhabitats for forest biodiversity and, on the other hand, at giving practical recommendations to forest managers who integrate the conservation of species diversity in their usual management. 1028 plots were set up in 210 French forests to observe about 55,000 trees. We studied the relationships between tree microhabitats and species richness and composition of 9 taxa. Through the analysis of key features for tree microhabitats at the tree and stand levels, we showed that tree species and diameter at breast height explain 26 and 31 % of the variations in microhabitat occurrence and diversity, respectively, in beech‐fir forest unlogged for more than 100 years. We highlighted significant diameter thresholds for the occurrence and diversity of microhabitats borne by beech (Fagus sylvatica L.) and silver fir (Abies alba Mill.). Furthermore, tree microhabitat density, deadwood volume and their diversity were shown to be roughly constant throughout the silvigenetic cycle in mountain mixed forests. Secondary tree species play a crucial role in the regulation of deadwood and microhabitat pools, especially during the phases where the dryad trees supply a low amount of microhabitats and deadwood. A surface of unharvested forest more than 10 hectares in area is necessary to observe the whole microhabitat diversity. Microhabitat occurrence patterns in logged forests were drastically different from those observed in forests unlogged for more than one century: tree microhabitats were systematically less diverse and the relative density of microhabitat types was modified. Moreover, the restoration of tree microhabitat pools was slow in set‐aside plain broadleaved forests. More than 30 years without harvests were not sufficient to observe the restoration of the tree microhabitat pool and significant changes in saproxylic beetle communities in all forest contexts. We measured the contribution of tree microhabitats to biodiversity, and we observed that the density of cavity‐ and fungus‐bearing trees were significant drivers for species richness and composition of saproxylic beetle assemblages. The density of trees bearing microhabitats, especially bark losses, significantly influenced the species richness of polypores. The stand openness and local climatic conditions affected these relationships in several forest‐taxon cases. We proposed a reference hierarchical typology of tree microhabitats in order to harmonize survey protocols and to facilitate data sharing in the future. Furthermore, we improved the consideration of tree microhabitats in an integrated management tool, i.e. the Potential Biodiversity Index (PBI). We also included the tree microhabitat pool into a simulation model of mountain forest dynamics (Samsara 2). Apart from being relevant management tools in conservation biology, tree microhabitats stand for natural microcosms available to further fundamental ecological researches. We hope that our work will help foresters to have a new insight on their managed forests.

Vam monitoritzar paràmetres físics i químics, macroinvertebrats bentònics, clorofil·la a, productors primaris i matèria orgànica durant un any (2001-2002) per examinar els efectes d'una font puntual sobre la composició taxonòmica, la estructura de la comunitat, l'organització funcional, la utilització de l'habitat i la estoquiometria al riu la Tordera (Catalunya).Aigües avall de la font puntual, concentració de nutrients, cabal i conductivitat eren majors que al tram d'aigües amunt, mentre que oxigen dissolt era menor. La densitat de macroinvertebrats era més elevada al tram d'aigües avall però la biomassa era similar als dos trams. La riquesa taxonòmica al tram de dalt era un 20% més alt que al tram de baix. Els anàlisis d'ordenació separen clarament els dos trams en el primer eix, mentre que els dos trams presentaven una pauta temporal similar en el segon eix. La similaritat entre els dos trams en composició taxonòmica, densitats i biomasses després de les crescudes d'abril i maig de 2002, indiquen que les pertorbacions del cabal poden actuar com a un mecanisme de reinici de la comunitat bentònica i jugar un paper important per a la restauració d'ecosistemes fluvials.Els dos trams presentaven una biomassa de perifiton, plantes vasculars, CPOM i FPOM similars, mentre que clorofil·la a, algues filamentoses, molses i SPOM eren majors al tram d'aigües avall. La densitat relativa de trituradors era menor sota la font puntual mentre que col·lectors i filtradors van ser afavorits. La biomassa relativa de trituradors també era menor sota la font puntual, però la biomassa de col·lectors i depredadors va augmentar. Les relacions entre densitat de grups tròfics i els seus recursos eren rarament significatives. La relació s'explicava millor amb la biomassa de macroinvertebrats. Els dos trams compartien la mateixa relació per raspadors, col·lectors i filtradors però no per trituradors i depredadors.La densitat i la biomassa de macroinvertebrats es trobaven positivament correlacionades amb la quantitat de recursos tròfics i la complexitat d'habitat, mentre que la riquesa taxonòmica es trobava negativament relacionada amb paràmetres hidràulics. La influència dels substrats inorgànics prenia menor rellevància per a la distribució dels macroinvertebrats. Els anàlisis d'ordenació mostren com les variables del microhabitat de major rellevància eren CPOM, clorofil·la a, algues filamentoses i velocitat. La cobertura de sorra només era significativa per al tram d'aigües amunt i les molses, al d'aigües avall. El número de correlacions significatives entre macroinvertebrats i les variables del microhabitat era més elevat per al tram de dalt que per al de baix, bàsicament per diferències en composició taxonòmica. La biomassa de macroinvertebrats va aportar una informació semblant a la obtinguda per la densitat.Perifiton i molses tenien uns continguts de nutrients similars en els dos trams. Els %C i %N d'algues filamentoses també eren similars en els dos trams però el %P sota la font puntual era el doble que al tram de dalt. Les relacions estoquiomètriques en CPOM, FPOM i SPOM eren considerablement menors sota la font puntual. Els continguts elementals i relacions van ser molt variables entre taxons de macroinvertebrats però no van resultar significativament diferents entre els dos trams. Dípters, tricòpters i efemeròpters presentaven una estoquiometria similar, mentre que el C i el N eren inferiors en moluscs i el P en coleòpters. Els depredadors presentaven un contingut en C i N més elevat que la resta de grups tròfics, mentre que el P era major en els filtradors. Els desequilibris elementals entre consumidors i recursos eren menors en el tram d'aigües avall. A la tardor i l'hivern la major font de nutrients va ser la BOM mentre que a la primavera i a l'estiu va ser el perifiton. / We monitored physical and chemical parameters, benthic macroinvertebrates, chlorophyll a, primary producers, and organic matter for one year (2001-2002) to assess the effect of a point source input on the taxa composition, community structure, functional organization, microhabitat distribution, and elemental stoichiometry in La Tordera stream (Catalonia, NE Spain).Below the point source, nutrient concentrations, discharge, and specific conductance were higher than at the upstream reach, while dissolved oxygen decreased. Total macroinvertebrate density was higher at the downstream reach than at the upstream reach. The two reaches did not differ in macroinvertebrate total biomass. On average, taxa richness at the upstream reach was 20% higher than at the downstream reach. Ordination analysis clearly separated the samples of the two reaches in the first axis and corroborated the effect of the point source on the benthic community. The two reaches followed a similar temporal pattern with respect to the distribution of taxa along the second axis. Higher similarities between the two reaches in taxa composition, densities and biomass after the spates of April and May 2002, suggest that flooding events may act as a reset mechanism for benthic communities and play an important role in stream restoration.The two reaches did not differ in standing stocks of periphyton, vascular plants, CPOM and FPOM. Chlorophyll a, filamentous algae, mosses, and SPOM concentrations were increased by the point source. Relative density of shredders was reduced at the downstream reach, whereas gatherers and filterers were enhanced. Relative biomass of shredders decreased below the point source as well, but gatherers diminished and predators increased. The relationships between density of functional feeding groups and their presumed food resources were rarely significant. The relation between consumers and their food resources was best explained through macroinvertebrate biomass. The two reaches had the same relationship for scrapers, gatherers, and filterers, but differed for shredders and predators.Macroinvertebrate density and biomass were positively correlated with food resources and complexity of habitat architecture while taxa richness was negatively correlated with hydraulic parameters. Inorganic substrate exerted a lesser influence on macroinvertebrate distribution. Ordination analysis revealed that the microhabitat variables of major relevance at the two reaches were CPOM, chlorophyll a, filamentous algae, and maximum water velocity. Sand coverage was only retained at the upstream reach and moss, at the downstream reach. The number of significant correlations between macroinvertebrates and microhabitat variables was higher at the upstream reach than at the downstream reach mainly because of higher taxa richness. Macroinvertebrate biomass provided similar information to that obtained from density in our study case.Periphyton and mosses had similar nutrient contents in the two reaches. The %C and %N filamentous algae was also similar in the two reaches, but %P below the point source was two times higher than that at the upstream reach. Stoichiometric ratios for CPOM, FPOM, and SPOM decreased considerably below the point source. Elemental contents and ratios were highly variable among macroinvertebrate taxa but did not differ significantly between the two reaches, indicating homeostatic regulation. Dipterans, caddisflies, and mayflies had similar elemental contents and stoichiometry, whereas C and N were lower in mollusks and P in beetles. Predators had the higher C and N contents, while %P was higher in filterers and lower in scrapers. Elemental imbalances between consumers and resources were amended at the downstream reach relative to the upstream reach. Macroinvertebrates represented, on average, relatively low nutrient storage in the ecosystem. At the upstream reach, autochthonous production represented the major input of nutrients into the ecosystem food web, whereas the major source of P for heterotrophic production at the downstream reach was represented by allochthonous inputs.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Distinct environmental characteristics can directly affect community structure, they offer varying conditions and resources, which allows each area to establish different groups of species. In this study we analyzed two amphibian assemblages between October 2012 and September 2013 in two areas with different degrees of environmental heterogeneity, one in the Caatinga (Monument Natural Grota do Angico - MNGA ) and the other in the Atlantic Rainforest (Refugio de Vida Silvestre Mata do Junco - RVSMJ), both in the state of Sergipe. We used information about the spatial and food niches and their relationships with ecological and historical factors. We analyzed 1,332 records (999 - RVSMJ 333 - MNGA) of 28 species (22 - RVSMJ and 15 - MNGA, nine common to both areas). The food and space niche overlap was relatively high in both study sites. Nine types of microhabitats were used by the species being the most common, regardless of the area, soil (45.1 %), water (23.7 %) and leaflitter (8.6%). The most important preys in their diets were Formicidae and Coleoptera in both areas. Individuals in the Atlantic rainforest were relatively smaller than those of the Caatinga area suggesting differentiated investments between reproduction and growth between the areas. The results suggest that the assemblages from both areas are influenced by historical or phylogenetic factors only in the use of space assets. Their diets are strongly influenced by the availability of resources the environment offers. / Características ambientais distintas podem afetar diretamente a estruturação das comunidades, pois oferecem recursos e condições variadas, o que permite que em cada área, grupos diferenciados de espécies se estabeleçam. Nesse estudo duas taxocenoses de anfíbios anuros foram analisadas entre outubro de 2012 e setembro de 2013, em duas áreas com diferentes graus de heterogeneidade ambiental, uma na Caatinga (Monumento Natural Grota do Angico MNGA) e outra de Mata Atlântica (Refugio da Vida Silvestre Mata do Junco RVSMJ), ambas no estado de Sergipe. Foram utilizadas informações sobre os nichos espacial e alimentar e suas relações com fatores ecológicos e históricos. Foram tomados 1.332 registros (999 - RVSMJ e 333 - MNGA) pertencentes a 28 espécies (22 RVSMJ e 15 MNGA, sendo nove comuns as duas áreas). A sobreposição de nicho espacial e alimentar foi relativamente alta em ambas as áreas. Nove tipos de microhábitats foram utilizados pelas espécies sendo os mais comuns, independente da área, solo (45,1%), água (23,7%) e folhiço (8,6%). As presas mais importantes das dietas foram Formicidae e Coleoptera em ambas as áreas. Os indivíduos da Mata Atlântica foram relativamente menores que os da Catinga sugerindo investimentos diferenciados em reprodução e crescimento entre as áreas. Os resultados obtidos sugerem que as taxocenoses de ambas as áreas são influenciadas por fatores históricos ou filogenéticos somente na utilização dos recursos espaciais. Suas dietas são fortemente influenciadas pelas disponibilidades de recursos que o ambiente oferece.

Submitted by Jean Medeiros (jeanletras@uepb.edu.br) on 2016-05-17T13:11:30Z No. of bitstreams: 1 PDF - Fabrício Correia Diniz.pdf: 1709834 bytes, checksum: 43e4f8c72a3f970f3e159f409f5fad74 (MD5) / Approved for entry into archive by Secta BC (secta.csu.bc@uepb.edu.br) on 2016-07-21T20:41:52Z (GMT) No. of bitstreams: 1 PDF - Fabrício Correia Diniz.pdf: 1709834 bytes, checksum: 43e4f8c72a3f970f3e159f409f5fad74 (MD5) / Made available in DSpace on 2016-07-21T20:41:52Z (GMT). No. of bitstreams: 1 PDF - Fabrício Correia Diniz.pdf: 1709834 bytes, checksum: 43e4f8c72a3f970f3e159f409f5fad74 (MD5) Previous issue date: 2016-02-16 / The composition and structure of the shrub and tree vegetation along the altitudinal gradient are reflections of environmental heterogeneity resultant from the interaction of several variables, resulting in the formation of distinct floristic arrangements. Aimed to evaluate and understand the formation and variance of shrub-tree communities along na altitudinal gradient in Brazilian semiarid according to variables abiotic and biotic. The search was accomplished along an altitudinal gradient in Serra da Arara in São João do Cariri/PB. It was established 100 permanent plots distributed in four transects 25 and each with 100 m², forming a continuum in the gradient, distant from one another 10 m, two on the slope northeast of the mountain range and two in the southeast side, including all plants with height ≥ 1 meter and DNS (diameter at ground level) ≥ 3 cm. Measured weekly rainfall, humidity, temperature and winds peed at three locals situated in the altitudes (up to 500 m), foot; (up to 600 m) intermediate altitude; (> 600 m) in the top and each parcel were measured the altitude, ground slope, soil depth, rockiness, amount of burlap and presence of terrestrial bromeliads. There was the formation of two distinct floristic groups, one (G1) at the lower altitudes (between 479 to 563 meters) and other (G2) in the higher altitudes plots (between 564 to 653 meters) with composition and structure that differed significantly. The rainfall, humidity, temperature and winds peed can not explain the formation of floristic groups. The altitude, the presence of Bromeliaceae and amount of burlap are the predictive variables which together with the slope, rockiness and soil depth influence on the formation of groups formed along the gradient. Conclude that these variables jointly with the species in each habitat floristic group act as filters, resulting in na environmental heterogeneity with distinct microhabitats forming. / A composição e estrutura da vegetação arbustiva-arbórea ao longo do gradiente altitudinal são reflexos da heterogeneidade ambiental resultante da interação de diversas variáveis, resultando na formação de arranjos florísticos distintos. Objetivou-se avaliar e compreender a formação e divergência de comunidades arbustivo-arbóreas ao longo de um gradiente altitudinal no semiárido brasileiro de acordo com variáveis abióticas e bióticas. O trabalho foi realizado ao longo de um gradiente altitudinal na Serra da Arara em São João do Cariri/PB. Estabeleceu-se 100 parcelas permanentes distribuídas em quatro transectos de 25 e cada uma com 100 m², formando um continuum no gradiente, distando uma da outra 10 m, dois na vertente nordeste da serra e dois na vertente sudeste, incluindo todas as plantas com altura ≥ 1 metro e DNS (diâmetro ao nível do solo) ≥ 3 cm. Mediu-se semanalmente a pluviosidade, umidade, temperatura e velocidade do vento em três pontos localizados nas altitudes de (até 500 m), sopé; (até 600m), altitude intermediária; (> 600 metros), topo e em cada parcela foram medidas a altitude, declividade do terreno, profundidade do solo, rochosidade, quantidade de serapilheira e presença de bromélias terrestres. Houve a formação de dois grupos florísticos distintos, um (G1) nas menores altitudes (entre 479 a 563 metros) e o outro (G2) as parcelas de maiores altitudes (entre 564 a 653 metros), com composição e estrutura que diferiram significativamente. A pluviosidade, umidade, temperatura e velocidade do vento não conseguem explicar a formação dos grupos florísticos. A altitude, presença de Bromeliaceae terrestres e quantidade de serrapilheira constituem as variáveis preditivas que juntamente com a declividade, rochosidade e profundidade do solo influenciam na formação dos grupos formados ao longo do gradiente. Conclui-se que estas variáveis juntamente com as espécies em cada grupo florístico atuam como filtros de habitat, resultando numa heterogeneidade ambiental com formação de microhabitats distintos.

In lowland river systems, in-channel, slow-flowing or still-water areas (still-water patches, SWPs) are considered to be important habitats for many organisms, particularly the early-life stages of fish and shrimp. However, the distribution of the early life-stages of fish and shrimp among these habitats appears to be very patchy and studies suggest that the quality and diversity of microhabitat conditions within SWPs and the accessibility of SWPs to spawning adults and dispersing young may be important determinants of their suitability as nursery habitat. The aims of this thesis were to examine the utilisation of still-water patches by fish and shrimp in a lowland river in relation to habitat suitability and accessibility, with particular emphasis on early-life stages. To determine the factors influencing habitat selection among SWPs, the environmental variability in SWP habitat, and both the distribution and the movement patterns of fish and shrimp, were examined in the Broken River, a lowland river in south-eastern Australia. SWP habitat was found to be highly spatially and temporally variable in the Broken River. SWPs differed in relation to permanence, accessibility and microhabitat variables, and all life-stages of fish and shrimp were found to be significantly spatially aggregated among SWPs. This suggests that individual SWPs may differ in their suitability as habitat, and/or in their accessibility to dispersing organisms and indicates either differential rates of retention, movement into SWPs, spawning effort or survival among SWPs for these organisms. Significant associations were found for all species and life-stages in relation to the microhabitat characteristics of SWPs. The two introduced species, carp and gambusia, were found to have fewer associations, which suggests that these species are habitat generalists. Cover and SWP morphology variables were shown to be important for all native species. Significant, positive associations were found for most species and life-stages with large, deep, SWPs containing instream cover, however, the extent of cover preferred was variable. It was hypothesised that large, deep SWPs that contain instream cover are more environmentally stable and provide better foraging efficiency and reduced competition for space, whilst also providing refuge from predators and, that they may be easier to locate than smaller patches. Specific associations with microhabitat variables differed among all species and life-stages, and this was attributed to differences in diet and predation rates. Consequently, generalised microhabitat relationships for particular life-stages or species could not be identified and the results from this thesis suggest that a diversity of microhabitat conditions are required to meet the differing requirements of various life-stages and species. Significant associations were also found for most groups in relation to the accessibility characteristics of SWPs, indicating that the ability of individuals to access SWPs is an important factor in determining their distribution among SWPs. This further suggests that movement is an important factor in the distribution pattern of fish and shrimp among SWPs. Significant associations were found for most groups in relation to patch isolation, adjacent hydraulic habitat and entrance conditions, indicating that landscape composition and configuration as well as boundary conditions may be important determinants of organisms being able to locate suitable patches. Associations with accessibility variables differed among species and life-stages, and may be attributable to differences in movement capabilities. Field manipulations of instream cover and entrance depth were conducted to further examine the habitat associations found. The results confirmed a positive relationship between instream cover and fish and shrimp abundances. No species, however, responded consistently to the manipulation of entrance depths, and this was attributed to water level rises throughout the experiment and/or the correlation of entrance depth with SWP depth. However, the results from the field manipulations suggested that deeper habitats are able to be exploited by small-bodied adults and larvae when significant levels of instream cover are also available as refuge from predation. In order to confirm the importance of movement in the selection of SWP habitat by fish and shrimp, the movement patterns of fish and shrimp into and out of SWPs were investigated. Whilst the results from this aspect of the study were inconclusive for fish, the results for shrimp confirmed that adults and larvae moved routinely into and out of SWPs. However, for all shrimp species, movement appeared to be limited to a certain period of larval development, indicating that SWP quality and stability may be more important at particular stages of development than others. The results of this thesis have demonstrated the importance of SWP quality and stability for fish and shrimp in the Broken River and have shown that habitat preferences vary among individual species and life-stages. Consequently, in order to manage for multiple species and life-stages, consideration must be given not only to the availability of SWPs, but also to their stability over time and to the availability of a diverse range of microhabitats. In addition, consideration must also be given to the accessibility of SWPs and this will require a greater knowledge of the specific spawning and dispersal requirements of the organisms which utilise these patches, in combination with a greater understanding of the impacts of flow modification on riverine landscape composition and configuration.

Les acariens microprédateurs du genre Dermanyssus (espèces du groupe gallinae), inféodés aux oiseaux, représentent un modèle pour l'étude d'association lâche particulièrement intéressant : ces arthropodes aptères font partie intégrante du microécosystème du nid (repas de sang aussi rapide que celui du moustique) et leurs hôtes sont ailés. En outre, D. gallinae est une espèce d'importance économique, ce qui rend possible des comparaisons entre colonisation de milieux anthropisés et sauvages. Au début de l'étude, les espèces du groupe gallinae sont très mal délimitées. Les caractères morphologiques utilisés sont variables au sein de l'espèces, voire de la population, très chevauchants entre espèces. Afin de mieux comprendre les exigences écologiques du développement de D. gallinae et d'appréhender ses voies de dissémination, une investigation comparative basée sur des séquences d'ADN entre espèces du groupe gallinae a été adoptée. Un cheminement d'ordre taxinomique a permis de poser les bases nécessaires. Ensuite, l'exploration de certaines caractéristiques écologiques du groupe gallinae en relation avec sa phylogénie (spécificité d'hôte, flexibilité évolutive) a été menée à bien. Une espèce a été décrite, D. apodis, une lignée de D. gallinae constitue aussi une probable espèce inédite et D. longipes regroupe deux entités. Des différences écologiques marquées entre D. gallinae et les autres espèces semblent résulter non seulement de l'activité humaine, mais aussi de caractéristiques intrinsèques. Aujourd'hui, le rôle des flux commerciaux dans la dispersion de D. gallinae en élevage de pondeuses s'avère primordial, au moins en France, celui des oiseaux sauvages presque nul.

Snake populations in the North American tallgrass prairie appear to be declining, yet data unavailability impedes the development of enhanced ecological understanding of snake species-habitat relationships and also hinders snake conservation efforts. This study addresses both issues for the snakes of Illinois in two steps. In a two-year mark-recapture study at twenty-two sites within six northern Illinois prairie preserves, I investigated snake species-habitat relationships using habitat variables at three scales: microhabitat (< 100 m), landscape (1 - 10 km), and regional (> 10 km). A total of 120 snakes representing seven species was captured using drift fence arrays associated with funnel traps and sheet metal cover. The low numbers and diversity of snakes captured, when compared to historic evidence, indicate that Illinois snake populations have declined. At the microhabitat scale, non-metric multidimensional scaling and Mantel tests revealed a relationship between snake species composition and elevation. At the landscape-scale, snake species composition varied along an agricultural-urban cover gradient. Classification and regression trees and maximum entropy models (Maxent) were used to identify the scales at which snake species-habitat relationships were strongest. Six of seven regression trees for individual snakes species contained habitat variables at the landscape scale. Important landscape characteristics included patch size, isolation, and land cover, metrics that strongly covary with habitat loss. Microhabitat features only appeared in the regression trees of two species and in three Maxent models. This study indicates that habitat loss has shaped the current distribution of snake species in Illinois's remnant prairies and that snake conservation efforts should emphasize the landscape-scale. Finally, I developed a risk ranking system based on natural and life history characteristics to assess the conservation status of Illinois's 38 snake species. Cluster analysis identified eight groups of snakes, similar in terms of risk factors, with high risk species sharing characteristics such as large body size, long life span, limited habitat breadth, and a high anthropogenic threat ranking. Here, I emphasize the need for basic demographic studies on snakes and suggest that ranking systems be used with population data (when available) and expert opinion to identify snake species of conservation concern in other regions. / Dissertation

Studies of secondary seed dispersal by small mammals have largely been focused on the interaction between nut-bearing tree species and sciurid rodents such as squirrels, and on heteromyid rodents in the southwestern United States. However, there is now evidence that wind-dispersed tree species such as pines also undergo a process of secondary seed dispersal, where animals redistribute (cache) seeds that have already fallen to the ground, often in microhabitats more suitable for successful seed germination. In Florida sandhill, where fire suppression has threatened wind-dispersed longleaf pine ( Pinus palustris) by encouraging the encroachment of hardwoods such as sand live oak ( Quercus geminata), secondary seed dispersal may be an important factor in determining community composition and persistence of longleaf pine systems. Using a combination of seed depots and seed predator exclosures, I looked at both longleaf pine and sand live oak in terms of whether small animals such as squirrels ( Sciurus carolinensis) and cotton mice ( Peromyscus gossypinus) cache the seeds, and where the seeds of these two tree species best germinate. Since sand live oak acorns are prone to infestation by weevils ( Curculio spp.), I also examined whether nut condition affects acorn germination potential. I found that longleaf pine seeds are cached by small mammals to a small degree. While these seeds are not moved great distances from where they originate, they are often redistributed into microhabitats that promote successful seed germination. Caging experiments indicated that seeds were most likely to germinate when buried in open areas between adult trees, and to some degree, under shrub cover. On the other hand, sand live oak acorns appear to face heavy predation by large seed predators such as raccoons ( Procyon lotor) and wild pigs (Sus scrofa). Those acorns that do escape predation, including weevil-infested acorns, may provide an opportunity for seedling establishment. However, it appears that sand live oak depends heavily on vegetative sprouting for regeneration. This suggests that even in the absence of fire, longleaf pines in Florida sandhill are able to persist through secondary seed dispersal by small animals coupled with heavy seed predation on competing sand live oak.