Dans le contexte actuel de crise de biodiversité, il est primordial de comprendre où et comment se distribuent les êtres vivants. En utilisant les données de biodiversité gérées par le GBIF (> 640 millions d'occurrences) et couvrant 24 classes taxonomiques, j'ai étudié un patron de biodiversité remarquable, le gradient latitudinal de diversité (LDG). Cet objectif m'a d'abord amené à produire des outils informatiques afin de manipuler ces données de biodiversité (Big Data), puis à évaluer la qualité des données. J’ai alors mis en évidence deux phénomènes importants. Premièrement, un fort biais taxonomique existe dans les données d'occurrences de biodiversité. Certains taxons sont plus étudiés que d'autres, créant un déficit de connaissance pour certains groupes et se révélant problématique pour notre compréhension globale de la biodiversité. Ce biais semble s'expliquer en partie par l'impact des préférences sociétales. Deuxièmement, un changement radical dans la production de ces données: de plus en plus de données primaires de biodiversité sont de simples observations et non plus des spécimens récoltés et mis en collection. Les dangers et avantages liés à ce changement de pratique sont discutés, le rôle de spécimens vouchers est rappelé et la nécessité d'acquérir des données supplémentaires est soulignée. Enfin, fort de cette analyse critique des données primaires de biodiversité, six hypothèses pouvant expliquer le LDG sont testées sur un jeu de données nettoyées couvrant huit classes taxonomiques. Ce test permet de réfuter une hypothèse de contrainte géométrique récente mais jamais testée pour finalement révéler que l'hypothèse de productivité est la mieux soutenue. / In the current context of biodiversity crisis, it is essential to understand where and how life is distributed. Using biodiversity data managed by the GBIF (>640 million occurrences) covering 24 taxonomic classes, I investigated one of the best-known biodiversity patterns: the latitudinal diversity gradient (LDG), which is characterized by an increase in specific richness as we approach the equator. This objective first led me to produce informatics tools for handling large amount of data (Big data paradigm), before evaluating the quality of primary biodiversity data. Two important outcomes resulted from this evaluation. First, I highlight that a strong taxonomic bias exists in biodiversity occurrences. This bias implies that some taxa are more studied than others, creating a knowledge gap detrimental to our understanding of biodiversity as a whole. This bias is strongly impacted by societal preferences rather than research activity. Second, a radical change in biodiversity data gathering practices is happening: primary biodiversity data are now mostly observation-based and not specimen-based. Assets and liabilities of this shift are discussed, while the role of voucher specimens is reiterated and, for observations, the need for ancillary data is underlined. Finally, six hypotheses proposed to explain the LDG are tested on a cleaned dataset encompassing eight taxonomic classes. A recent, but never tested, version of the geometric constraint hypothesis is refuted, while the productivity hypothesis is strongly supported.

As restingas constituem um mosaico de ambientes presentes nas planícies costeiras brasileiras. Sua vegetação se desenvolve em areias quartzosas e engloba variadas formações, de comunidades herbáceas de dunas até florestas. A restinga sulbrasileira se estende entre as latitudes 28°30'S, no estado de Santa Catarina, e 33°45'S, no extremo sul do Rio Grande do Sul. Esta tese visou compreender, em escala geográfica mais ampla, a influência de variáveis ambientais sobre a estrutura e composição dos componentes arbóreo e herbáceo-subarbustivo nas florestas da restinga sulbrasileira. Em 15 remanescentes florestais distribuídos nessa região, realizou-se a caracterização florística e fitossociológica do componente arbóreo e verificou-se a relação entre diversidade, latitude e variáveis climáticas. O levantamento do componente arbóreo foi feito em áreas de 0,1 ha em cada remanescente, subdivididas em 10 parcelas de 10 x 10 m. Todas as árvores com DAP>= 3,0 cm foram registradas. Com os parâmetros estruturais usuais em fitossociologia foi feita uma análise da variância, comparando-se os remanescentes. Também foi avaliada a composição do solo superficial (20 cm de profundidade) dos remanescentes. Os dados de riqueza e informações sobre temperatura atmosférica e precipitação foram empregados em análises de regressão para verificar sua relação com a latitude. Realizou-se ainda uma Análise de Agrupamento para avaliar a similaridade florística entre as áreas. A composição e estrutura do componente herbáceo-subarbustivo sob diferentes níveis de uso por gado bovino nos remanescentes também foi estudada. A fitossociologia da sinúsia herbácea-subarbustiva foi feita em 10 parcelas de 1,0 m² e a florística, nas 10 parcelas de 10 x 10 m. Registrou-se a intensidade de uso por gado através de visualização direta ou vestígios dos animais. Foram feitas análise da variância e Análise de Coordenadas Principais com índices estruturais da sinúsia herbácea-subarbustiva nos remanescentes, comparando-os quanto à intensidade de uso por gado bovino. Registraram-se 116 espécies arbóreas no total, porém a riqueza variou de 11 a 43 espécies por remanescente. Espécies provenientes por mais de uma rota de imigração e pelo corredor atlântico contribuíram com 43% e 39% dessa flora, respectivamente. A diversidade arbórea variou de 1,372 a 3,175 nats/ind. O componente arbóreo apresentou densidade entre 1.520 e 3.830 ind./ha, porte baixo e predomínio de diâmetros pequenos. Constataram-se diferenças significativas na estrutura do componente arbóreo entre alguns remanescentes. Essas diferenças podem estar relacionadas a variações nas condições de fertilidade, acidez e teores de alumínio no solo. Houve uma distinção florística no componente arbóreo entre o norte e o centro-sul da restinga sulbrasileira, além de gradientes de riqueza e diversidade no sentido norte-sul relacionados às condições de temperatura e precipitação. Para a sinúsia herbácea-subarbustiva, constataram-se diferenças significativas no conjunto de variáveis estruturais (cobertura, altura e medidas de diversidade) entre remanescentes sob níveis médio e alto de uso por gado bovino. Sob alta intensidade de uso por gado bovino, a sinúsia herbácea-subarbustiva apresenta menores valores de altura, riqueza, diversidade e equabilidade e alta dominância de poucas espécies. O estudo destes componentes permitiu verificar que variáveis edáficas, climáticas e antrópicas condicionam a estrutura florestal em diferentes intensidades e/ou escalas espaciais. / (Structure and phytogeographic features of forest remnants in south Brazilian restinga). Restingas comprise a mosaic of environments present in Brazilian coastal plains. Its vegetation grows in quartzarenic sands and includes several formations, from dune herb communities to forests. South Brazilian restinga extents between latitudes 28°30'S, in Santa Catarina state, and 33°45'S, in the extreme southern of Rio Grande do Sul. This thesis aimed to investigate, in broader geographical scale, the influence of environmental variables on structure and composition of tree and herb-subshrubby components in south Brazilian restinga forests. We analysed the floristic and phytosociological patterns of tree component and the relation among diversity, latitude and climatic variables into 15 forest remnants distributed in this region. Tree component survey was carried out in 0.1 ha areas, subdivided in 10 x 10 m plots. All trees with DBH >= 3.0 cm were sampled. With structural parameters usually estimated in phytosociology an ANOVA was performed to seek for relations among the remnants. The composition of superficial soil (20 cm deep) was also assessed in the remants. Richness, atmospheric temperature and rainfall data were employed in regression analyses to verify its relation to latitude. A Cluster Analysis was also performed to evaluate floristic similarity among areas. Composition and structure of herb-subshrubby component under different levels of cattle usage in remnants was studied as well. Phytosociology of herb-subshrubby synusiae was carried out in 10 plots of 1.0 m² and the floristics was accomplished in those 10 x 10 m plots. The intensity of cattle usage was registered by direct observation or animal traces. We performed an ANOVA and Principal Coordinates Analysis with herb-subshrubby structural data among remnants to compare them in relation to cattle usage levels. We sampled 116 tree species, but remnant richness varied from 11 to 43 species. Species from more than one immigration route and from the Atlantic route contributed with 43% and 39% of this flora, respectively. Diversity of trees varied from 1.372 to 3.175 nats/ind. Tree synusiae had density between 1,520 and 3,830 ind./ha, low height and predominance of small diameters. Significant differences in tree component structure were observed among some remnants. These differences may be related to variations in conditions of soil fertility, acidity and aluminium content. A floristic distinction between the northern and the central-southern portion of south Brazilian restinga was verified, besides richness and diversity gradients towards north-south associated to temperature and rainfall conditions. For herb-subshrubby synusiae, significant differences were observed in the set of structural variables (coverage, height and diversity measures) among remnants under moderate and high cattle-using levels. Under high cattle-using levels, herb-subshrubby synusiae shows lower values of height, richness, diversity and eveness, and higher dominance of few species. The study of these components permited to verify that soil, climatic and anthropic variables determined forest structure in different intensities and/or spatial scales.

As restingas constituem um mosaico de ambientes presentes nas planícies costeiras brasileiras. Sua vegetação se desenvolve em areias quartzosas e engloba variadas formações, de comunidades herbáceas de dunas até florestas. A restinga sulbrasileira se estende entre as latitudes 28°30'S, no estado de Santa Catarina, e 33°45'S, no extremo sul do Rio Grande do Sul. Esta tese visou compreender, em escala geográfica mais ampla, a influência de variáveis ambientais sobre a estrutura e composição dos componentes arbóreo e herbáceo-subarbustivo nas florestas da restinga sulbrasileira. Em 15 remanescentes florestais distribuídos nessa região, realizou-se a caracterização florística e fitossociológica do componente arbóreo e verificou-se a relação entre diversidade, latitude e variáveis climáticas. O levantamento do componente arbóreo foi feito em áreas de 0,1 ha em cada remanescente, subdivididas em 10 parcelas de 10 x 10 m. Todas as árvores com DAP>= 3,0 cm foram registradas. Com os parâmetros estruturais usuais em fitossociologia foi feita uma análise da variância, comparando-se os remanescentes. Também foi avaliada a composição do solo superficial (20 cm de profundidade) dos remanescentes. Os dados de riqueza e informações sobre temperatura atmosférica e precipitação foram empregados em análises de regressão para verificar sua relação com a latitude. Realizou-se ainda uma Análise de Agrupamento para avaliar a similaridade florística entre as áreas. A composição e estrutura do componente herbáceo-subarbustivo sob diferentes níveis de uso por gado bovino nos remanescentes também foi estudada. A fitossociologia da sinúsia herbácea-subarbustiva foi feita em 10 parcelas de 1,0 m² e a florística, nas 10 parcelas de 10 x 10 m. Registrou-se a intensidade de uso por gado através de visualização direta ou vestígios dos animais. Foram feitas análise da variância e Análise de Coordenadas Principais com índices estruturais da sinúsia herbácea-subarbustiva nos remanescentes, comparando-os quanto à intensidade de uso por gado bovino. Registraram-se 116 espécies arbóreas no total, porém a riqueza variou de 11 a 43 espécies por remanescente. Espécies provenientes por mais de uma rota de imigração e pelo corredor atlântico contribuíram com 43% e 39% dessa flora, respectivamente. A diversidade arbórea variou de 1,372 a 3,175 nats/ind. O componente arbóreo apresentou densidade entre 1.520 e 3.830 ind./ha, porte baixo e predomínio de diâmetros pequenos. Constataram-se diferenças significativas na estrutura do componente arbóreo entre alguns remanescentes. Essas diferenças podem estar relacionadas a variações nas condições de fertilidade, acidez e teores de alumínio no solo. Houve uma distinção florística no componente arbóreo entre o norte e o centro-sul da restinga sulbrasileira, além de gradientes de riqueza e diversidade no sentido norte-sul relacionados às condições de temperatura e precipitação. Para a sinúsia herbácea-subarbustiva, constataram-se diferenças significativas no conjunto de variáveis estruturais (cobertura, altura e medidas de diversidade) entre remanescentes sob níveis médio e alto de uso por gado bovino. Sob alta intensidade de uso por gado bovino, a sinúsia herbácea-subarbustiva apresenta menores valores de altura, riqueza, diversidade e equabilidade e alta dominância de poucas espécies. O estudo destes componentes permitiu verificar que variáveis edáficas, climáticas e antrópicas condicionam a estrutura florestal em diferentes intensidades e/ou escalas espaciais. / (Structure and phytogeographic features of forest remnants in south Brazilian restinga). Restingas comprise a mosaic of environments present in Brazilian coastal plains. Its vegetation grows in quartzarenic sands and includes several formations, from dune herb communities to forests. South Brazilian restinga extents between latitudes 28°30'S, in Santa Catarina state, and 33°45'S, in the extreme southern of Rio Grande do Sul. This thesis aimed to investigate, in broader geographical scale, the influence of environmental variables on structure and composition of tree and herb-subshrubby components in south Brazilian restinga forests. We analysed the floristic and phytosociological patterns of tree component and the relation among diversity, latitude and climatic variables into 15 forest remnants distributed in this region. Tree component survey was carried out in 0.1 ha areas, subdivided in 10 x 10 m plots. All trees with DBH >= 3.0 cm were sampled. With structural parameters usually estimated in phytosociology an ANOVA was performed to seek for relations among the remnants. The composition of superficial soil (20 cm deep) was also assessed in the remants. Richness, atmospheric temperature and rainfall data were employed in regression analyses to verify its relation to latitude. A Cluster Analysis was also performed to evaluate floristic similarity among areas. Composition and structure of herb-subshrubby component under different levels of cattle usage in remnants was studied as well. Phytosociology of herb-subshrubby synusiae was carried out in 10 plots of 1.0 m² and the floristics was accomplished in those 10 x 10 m plots. The intensity of cattle usage was registered by direct observation or animal traces. We performed an ANOVA and Principal Coordinates Analysis with herb-subshrubby structural data among remnants to compare them in relation to cattle usage levels. We sampled 116 tree species, but remnant richness varied from 11 to 43 species. Species from more than one immigration route and from the Atlantic route contributed with 43% and 39% of this flora, respectively. Diversity of trees varied from 1.372 to 3.175 nats/ind. Tree synusiae had density between 1,520 and 3,830 ind./ha, low height and predominance of small diameters. Significant differences in tree component structure were observed among some remnants. These differences may be related to variations in conditions of soil fertility, acidity and aluminium content. A floristic distinction between the northern and the central-southern portion of south Brazilian restinga was verified, besides richness and diversity gradients towards north-south associated to temperature and rainfall conditions. For herb-subshrubby synusiae, significant differences were observed in the set of structural variables (coverage, height and diversity measures) among remnants under moderate and high cattle-using levels. Under high cattle-using levels, herb-subshrubby synusiae shows lower values of height, richness, diversity and eveness, and higher dominance of few species. The study of these components permited to verify that soil, climatic and anthropic variables determined forest structure in different intensities and/or spatial scales.

O camarão corrupto Callichirus seilacheri foi erigido por Bott (1955) através de uma breve e incompleta descrição carente da maioria das ilustrações sobre as principais estruturas corporais desta espécie. Callichirus seilacheri é considerada, atualmente, como o único representante do gênero Callichirus na costa do Pacífico Leste. Sua distribuição geográfica abrange um amplo gradiente latitudinal de aproximadamente 50º graus (~13º N - 37º S) desde a praia Los Blancos (localidade-tipo), El Salvador até Lenga na costa de Chile. O estado taxonômico da grande população de C. seilacheri tem sido questionado no passado em reiteradas oportunidades. Este questionamento tem relação com a falta de estudos taxonômicos associados com estas populações e com o fato que alguns antecedentes moleculares têm demonstrado que as populações de Callichirus da costa do Pacífico de Nicarágua e México são diferentes. Considerando estes antecedentes, o primero objetivo do presente estudo foi avaliar o estado taxonômico de C. seilacheri na costa do Pacífico Leste da América Central. Para isto, foi coletado material de C. seilacheri em diferentes localidades da costa do Pacifico de América Central, incluindo a localidade-tipo desta espécie na costa de El Salvador. Conforme as observações morfológicas do material coletado, os caracteres diagnósticos de C. seilacheri incluem entre outros aspectos: (i) pedúnculos oculares com uma alongada projeção pré-córneal, cujas pontas divergem lateralmente; (ii) segmentos terminais do pedúnculo antênular e antenal com as bases paralelas; e (iii) pereiópodo maior do primeiro par de pereiópodos dos machos adultos com o mero armado de um lóbulo retangular na região ventral anterior e ísquio curvado para baixo com um gancho na margem ventral. Uma das descobertas mais relevantes foi que todas as fêmeas de C. seilacheri têm ambos gonóporos masculino e feminino, o qual representa o primeiro registro de intersexualidade no gênero Callichirus. O segundo objetivo desta tese foi avaliar se a espécie da costa chilena Callichirus garthi (Retamal, 1975), considerada como uma sinonímia-junior de C. seilacheri da costa do Pacífico da América Central, é uma espécie válida. Para isto, comparou-se o material-tipo de C. garthi e outros lotes desta espécie coletados ao longo da costa de Chile (~18º e 37º S) com os espécimes de C. seilacheri coletados na localidade-tipo (Playa Los Blancos, El Salvador) e em outras localidades da América Central. A comparação morfológica revelou importantes diferenças morfológicas entre os tipos morfológicos identificados em ambas espécies. Entre as principais diferenças e possível mencionar que C. garthi possui as pontas dos pedúnculos oculares paralelas, enquanto que em C. seilacheri são divergentes formando um angulo de 60-70°. Os machos adultos de ambas espécies compartilham quelípodos desiguais na fase adulta, mas somente, C. seilacheri tem um gancho sobre a margem ventral do ísquio e um lóbulo meral retangular. A analise morfológica do material biológico coletado em ambas regiões permite concluir que os espécimes coletados ao longo da costa do Chile pertencem à C. garthi, enquanto que os exemplares coletados na costa do Pacífico da Costa Rica pertencem à espécie C. seilacheri. Conforme a essas informações, C. garthi é uma espécie válida. Portanto, sugere-se a separação da grande população de C. seilacheri em duas diferentes populações: (i) uma pertencente ao C. seilacheri a qual ocorre desde a costa do El Salvador ate Costa Rica (~19º N 08º N), (ii) outra pertencente ao C. garthi a qual ocorre entre os 18º S e 37º S da costa chilena. A hipótese do centro abundância (HCA) é baseada na suposição de que as retricções fisiológicas limitam o desenvolvimento das populações nas bordas do seu intervalo de distribuição. Com o intuito de testar a validez desta hipótese, espécimes da espécie modelo Callichirus garthi foram coletados em sete populações distribuídas ao longo da costa chilena. Em cada população foram avaliados a densidade junto com uma serie de atributos populacionais de C. garthi (e.g. tamanho máximo do corpo, razão sexual, etc). Os principais resultados revelaram que C. garthi foi significativamente menos abundante nas populações locais, perto do centro e aumentou para as bordas norte e sul da sua distribuição na costa do Chile. No extremo sul e norte da distribuição, a estrutura da população foi composta por indivíduos de todos os tamanhos, em contraste com às localidades do centro, onde os indivíduos estavam concentrados em uma faixa de tamanho mais estreita. Surpreendentemente, nas bordas (norte e sul), à razão entre os sexos foi estremamente equilibrada. A abundância local foi levemente correlacionada com a distância entre cada localidade e o rio mais próximo e foi fortemente correlacionada com a estrutura da população. Aparentemente, a proximidade de um rio oferece as condições ideais para que C. garthi forme populações densas e equilibradas, o qual seria um reflexo do sucesso a nível individual que esta espécie atinge em direção às bordas. O modelo de distribuição de abundância de C. garthi pode ser considerado como uma exceção nas populações naturais devido que na maioria dos estudos prévios nesta matéria o modelo usualmente reportado é o modelo normal de abundância para um dos extremos. As generalizações acerca do padrão reprodutivo dos invertebrados bentônicos costeiros propõem que as espécies tropicais tenham reprodução do tipo continua, como reflexo das baixas oscilações térmicas ao longo de todo o ano (hipótese de Orton). Com o propósito de testar esta suposição em um ambiente tropical da América, foram realizados durante um ano amostragens mensais em uma população de C. seilacheri da costa do Pacífico de Costa Rica (América Central). Os resultados revelaram que C. seilacheri tem uma marcada sazonalidade reprodutiva, a qual contradiz os padrões esperados em regiões tropicais. As fêmeas ovígeras estiveram presentes desde maio até novembro, o que está estatisticamente relacionado com a diminuição da salinidade durante a estação chuvosa. A temperatura não teve influência sobre a periodicidade reprodutiva. Aparentemente, à reprodução em C. seilacheri está fortemente relacionada com a variabilidade climática da costa do Pacífico na Costa Rica, sendo desencadeada por oscilações na salinidade. Uma comparação entre C. garthi da costa chilena e C. seilacheri da costa do Pacífico da América Central revelou importantes diferenças na produção de ovos. Callichirus seilacheri produz uma media de quatro menos ovos e menores que C. garthi da costa do Chile. A variabilidade nas características reprodutivas (produção e tamanho dos ovos) e de tamanho corporal dos indivíduos observada nestas duas espécies de camarões corruptos sugerem a imposição de importantes restrições fisiológicas dadas principalmente por a temperatura em ambas às regiões da América. Os aspectos examinados no presente estudo constituem novos antecedentes sobre a taxonômia, morfologia e ecología em um dos gêneros da família Callianassidae mais representativos nas praias de areia da América. Cada um destas informações pode ser considerado de especial relevância para a conservação das populações de C. garthi e C. seilacheri no Pacífico Leste. Especialmente, porque ambas espécies são frequentemente recolhidas como isca para a pesca comercial e esportiva em algumas pequenas vilas costeiras. / The ghost shrimp Callichirus seilacheri was erected by Bott (1955) through a brief and poorly illustrated description. This species is considered as the only one current representative of genus Callichirus along the eastern Pacific. Their distribution encompasses approximately 50 degree of latitude, from Los Blancos, El Salvador (13º N) to Lenga, Chile (37º S). The identity of the large population of C. seilacheri along the Pacific coast of Americas has been questioned by different researchers whom have indicated the existence of more than one species of Callichirus for the Pacific coast of Mexico and the Pacific coast of Costa Rica and Nicaragua. Considering this information, the first focus of this thesis was realize a redescription of C. seilacheri based on specimens collected in different localities from Central America, including the type-locality of this species. According to the observations, the diagnostic features of C. seilacheri include (i) the eyestalks with elongated precorneal projection with tips diverging laterally; (ii) terminal segments of antennular peduncle and antennal with the parallel base and (iii) adult male with larger cheliped with rough rectangular lobe over anterior ventral margin of merus, ischium curved downward with a hook on ventral margin. All females analyzed herein have both male and female gonopores, thus firstly recorded the presence of intersex within the genus Callichirus. The second objective of this thesis was test whether Callichirus garthi (Retamal, 1975) which is considered as a junior synonymy of C. seilacheri constitute a valid species for the eastern Pacific. For this, a full comparison between specimens of the genus Callichirus collected along the Pacific coast of Central America and Chilean coast, including the type-locality of C. seilacheri and C. garthi was realized. The comparison revealed important morphological differences between both species. For example, in C. garthi the tips of the eyestalk are parallel while diverge distally forming an about 60-70° angle in C. seilacheri. Adult males of both species share unequal chelipeds; however, only C. seilacheri has a hook on ventral margin of ischium and its merus is armed with a rectangular lobe over anterior ventral margin. Additional material collected along the Chilean coast and from different localities from the Pacific coast of Costa Rica allowed confirms the taxonomic status of both species in the Eastern Pacific. All specimens collected along the Chilean coast belong to C. garthi while those of Costa Rica fit to form of C. seilacheri from El Salvador. According to the results, C. garthi is a valid species. Therefore, it is postulated the separation of large population of C. seilacheri into two different populations: (i) one belonging to C. seilacheri which distributes from Mexico to Costa Rica (~19º 08º N), (ii) other assigned to C. garthi which encompasses, at least, between 18º S 37º S of the Chilean coast. The abundant-centre hypothesis (ACH) is based on the assumption that physiological constraints limit populations at the edges of their distributional range. In the third chapter is examined the applicability of the ACH in a marine system by testing whether physiological predictions are reflected in large-scale variations of life-history traits. In order to achieve this information, specimens of Callichirus garthi were collected in the intertidal zone at seven sampling sites. In each site we evaluated (i) local abundance, (ii) maximum body size, (iii) sex-ratio, (iv) length-size frequency distribution, and (v) size at maturity. The main outcomes revealed that C. garthi is a species of low occurrence which was present in seven of all visited beaches (N = 61). Callichirus garthi was clearly less abundant within local populations near the centre and increased towards the northern and southern edges of its distribution. This pattern of abundance was significantly fitted by the abundant edge model. At the southern end and northern of the distribution, population structure was composed by individuals of all sizes in contrast with localities from the centre where individuals were concentrated in a narrow size range. Surprisingly at the edges (north and south), the sex ratio was extremely balanced. Physical variables (SST, grain size) had not influences on variation of life-history traits; however, the local abundance was slightly correlated with the distance between each locality and the closest river and was strongly correlated with population structure. Overall, the observed pattern was intimately linked with input of nutrients from the closest rivers. The findings allow separate the great population of C. garthi along the Chilean coast in two kinds: (A) stable populations (at the border of distribution), and (B) unstable populations (at the centre of distribution). In both cases, the population demography is controlled by dense-dependent factors. The results underline the importance of incorporating ecological, physiological and life-history studies in future tests of the ACH. Generalizations about breeding patterns of near-shore benthic marine invertebrates have proposed that tropical species have continuous reproduction as a reflection of constant temperature throughout the year (Ortons hypothesis). Based on this assumption, it was analysed the reproductive periodicity and egg production in the intertidal ghost shrimp Callichirus seilacheri from the Central Pacific coast of Costa Rica. In order to obtain such information, a total of 449 individuals were collected monthly from December 2011 to November 2012. The results showed that females with ovaries filled with mature oocytes were present throughout the whole year. However, the presence of ovigerous females was restricted to the period between May and November which fits to a seasonal breeding cycle. Apparition of egg-bearing females was statistically correlated with the decrease of salinity detected during rainy season, but not with temperature. Compared to C. garthi from temperate waters, C. seilacheri produced on the average four times less eggs and smaller. Variability in reproductive features and body size of these species seem to reflect physiological constraints imposed by temperature in cold and warm regions. The aspects examined in each chapter of this thesis constitute new antecedents about morphology, taxonomy, and ecology of one of the most representative genus of the family Callianassidae from American coast. Each one of these informations may be considered of especial importance for the management and conservation of the Callichiruss populations from the eastern Pacific. Especially, because both species herein analyzed are frequently collected as bait for commercial and recreational fishing in some small villages along Pacific coast of America.

As restingas constituem um mosaico de ambientes presentes nas planícies costeiras brasileiras. Sua vegetação se desenvolve em areias quartzosas e engloba variadas formações, de comunidades herbáceas de dunas até florestas. A restinga sulbrasileira se estende entre as latitudes 28°30'S, no estado de Santa Catarina, e 33°45'S, no extremo sul do Rio Grande do Sul. Esta tese visou compreender, em escala geográfica mais ampla, a influência de variáveis ambientais sobre a estrutura e composição dos componentes arbóreo e herbáceo-subarbustivo nas florestas da restinga sulbrasileira. Em 15 remanescentes florestais distribuídos nessa região, realizou-se a caracterização florística e fitossociológica do componente arbóreo e verificou-se a relação entre diversidade, latitude e variáveis climáticas. O levantamento do componente arbóreo foi feito em áreas de 0,1 ha em cada remanescente, subdivididas em 10 parcelas de 10 x 10 m. Todas as árvores com DAP>= 3,0 cm foram registradas. Com os parâmetros estruturais usuais em fitossociologia foi feita uma análise da variância, comparando-se os remanescentes. Também foi avaliada a composição do solo superficial (20 cm de profundidade) dos remanescentes. Os dados de riqueza e informações sobre temperatura atmosférica e precipitação foram empregados em análises de regressão para verificar sua relação com a latitude. Realizou-se ainda uma Análise de Agrupamento para avaliar a similaridade florística entre as áreas. A composição e estrutura do componente herbáceo-subarbustivo sob diferentes níveis de uso por gado bovino nos remanescentes também foi estudada. A fitossociologia da sinúsia herbácea-subarbustiva foi feita em 10 parcelas de 1,0 m² e a florística, nas 10 parcelas de 10 x 10 m. Registrou-se a intensidade de uso por gado através de visualização direta ou vestígios dos animais. Foram feitas análise da variância e Análise de Coordenadas Principais com índices estruturais da sinúsia herbácea-subarbustiva nos remanescentes, comparando-os quanto à intensidade de uso por gado bovino. Registraram-se 116 espécies arbóreas no total, porém a riqueza variou de 11 a 43 espécies por remanescente. Espécies provenientes por mais de uma rota de imigração e pelo corredor atlântico contribuíram com 43% e 39% dessa flora, respectivamente. A diversidade arbórea variou de 1,372 a 3,175 nats/ind. O componente arbóreo apresentou densidade entre 1.520 e 3.830 ind./ha, porte baixo e predomínio de diâmetros pequenos. Constataram-se diferenças significativas na estrutura do componente arbóreo entre alguns remanescentes. Essas diferenças podem estar relacionadas a variações nas condições de fertilidade, acidez e teores de alumínio no solo. Houve uma distinção florística no componente arbóreo entre o norte e o centro-sul da restinga sulbrasileira, além de gradientes de riqueza e diversidade no sentido norte-sul relacionados às condições de temperatura e precipitação. Para a sinúsia herbácea-subarbustiva, constataram-se diferenças significativas no conjunto de variáveis estruturais (cobertura, altura e medidas de diversidade) entre remanescentes sob níveis médio e alto de uso por gado bovino. Sob alta intensidade de uso por gado bovino, a sinúsia herbácea-subarbustiva apresenta menores valores de altura, riqueza, diversidade e equabilidade e alta dominância de poucas espécies. O estudo destes componentes permitiu verificar que variáveis edáficas, climáticas e antrópicas condicionam a estrutura florestal em diferentes intensidades e/ou escalas espaciais. / (Structure and phytogeographic features of forest remnants in south Brazilian restinga). Restingas comprise a mosaic of environments present in Brazilian coastal plains. Its vegetation grows in quartzarenic sands and includes several formations, from dune herb communities to forests. South Brazilian restinga extents between latitudes 28°30'S, in Santa Catarina state, and 33°45'S, in the extreme southern of Rio Grande do Sul. This thesis aimed to investigate, in broader geographical scale, the influence of environmental variables on structure and composition of tree and herb-subshrubby components in south Brazilian restinga forests. We analysed the floristic and phytosociological patterns of tree component and the relation among diversity, latitude and climatic variables into 15 forest remnants distributed in this region. Tree component survey was carried out in 0.1 ha areas, subdivided in 10 x 10 m plots. All trees with DBH >= 3.0 cm were sampled. With structural parameters usually estimated in phytosociology an ANOVA was performed to seek for relations among the remnants. The composition of superficial soil (20 cm deep) was also assessed in the remants. Richness, atmospheric temperature and rainfall data were employed in regression analyses to verify its relation to latitude. A Cluster Analysis was also performed to evaluate floristic similarity among areas. Composition and structure of herb-subshrubby component under different levels of cattle usage in remnants was studied as well. Phytosociology of herb-subshrubby synusiae was carried out in 10 plots of 1.0 m² and the floristics was accomplished in those 10 x 10 m plots. The intensity of cattle usage was registered by direct observation or animal traces. We performed an ANOVA and Principal Coordinates Analysis with herb-subshrubby structural data among remnants to compare them in relation to cattle usage levels. We sampled 116 tree species, but remnant richness varied from 11 to 43 species. Species from more than one immigration route and from the Atlantic route contributed with 43% and 39% of this flora, respectively. Diversity of trees varied from 1.372 to 3.175 nats/ind. Tree synusiae had density between 1,520 and 3,830 ind./ha, low height and predominance of small diameters. Significant differences in tree component structure were observed among some remnants. These differences may be related to variations in conditions of soil fertility, acidity and aluminium content. A floristic distinction between the northern and the central-southern portion of south Brazilian restinga was verified, besides richness and diversity gradients towards north-south associated to temperature and rainfall conditions. For herb-subshrubby synusiae, significant differences were observed in the set of structural variables (coverage, height and diversity measures) among remnants under moderate and high cattle-using levels. Under high cattle-using levels, herb-subshrubby synusiae shows lower values of height, richness, diversity and eveness, and higher dominance of few species. The study of these components permited to verify that soil, climatic and anthropic variables determined forest structure in different intensities and/or spatial scales.

The Florida Reef Tract (FRT) extends from the tropical Caribbean northward along the Florida coast into a warm temperate environment where tropical reef communities diminish with increasing latitude. This study was designed to map the nearshore benthic habitats including coral reefs and evaluate how the benthic communities differ between habitats and along the coast. Benthic communities across the northern FRT from Key Biscayne to Hillsboro Inlet (25.5°-26.3° N) were digitized from aerial photography taken in 2013 at a 1:1,000 scale. Three main hard-bottom habitat types were identified that ran parallel to shore and consecutively further away from shore: Colonized Pavement, Ridge, and Inner Reef. Five 1-km wide cross-shelf corridors (numbered 1-5, south to north) were designated and spaced as evenly as possible throughout the region. Five sites per habitat per corridor (70 total) were randomly selected and quantitative data collected within 4,200 m2. Significant differences in percent benthic cover among habitats were found in all corridors and within habitat types between corridors, indicating cross-shelf and latitudinal variation. Mean stony coral density increased with depth, with the Inner Reef habitat being significantly higher than both the Colonized Pavement and Ridge. Mean stony coral species richness also increased with depth, with all habitats significantly different from one another. A total of 22 stony coral species were identified within the mapped region, the three most abundant being Porites astreoides, Siderastrea siderea, and Acropora cervicornis. Results from this study support the ecosystem regions denoted in the Walker (2012) study. Corridor 1, located in the Biscayne Region, was the only corridor to contain any seagrass. In addition, Corridor 1 Inner Reef had significantly higher values for mean stony coral density, mean stony coral species richness, mean gorgonian density of the plume morphotype, and mean density of stony corals infected with Cliona spp. Corridors 2-4, located in the Broward-Miami Region, had some variability associated with them, but were generally similar in benthic composition. Corridor 5, likewise located in the Broward-Miami Region but in close proximity to the Deerfield Region, also had differences associated with it. Both the Colonized Pavement and Ridge habitats in Corridor 5 had the lowest mean coral species richness, as well as total absence of both sponge species noted in this study. Corridor 5 Inner Reef also had significantly lower mean stony coral densities compared to Corridors 1, 2, and 4. As such, these results support the idea of different biogeographic regions occurring off the southeastern Florida coast. This study produced two key findings. It discovered over 110 large (>2 m) resilient coral colonies, of which 50 were alive in various conditions. This study also found 38 acres of dense Acropora cervicornis patches, tripling the previously known area within the study region. These are the largest dense patches in the continental United States.

Latitudinal gradient of diversity is typically being explained by the three main hypotheses: The Resources Limitation Hypothesis, The Speciation Rate Hypothesis and The Niche Conservatism Hypothesis. In my study I tested basic assumptions of these hypotheses using native and non-native vascular plants obtained from the new database GloNAF (Global Naturalized Alien Flora). I tested an effect of precipitation, NPP, temperature and historical velocity (difference in temperature and precipitation between the Last Glacial Maximum and present) on species richness. Given that the distribution of non-native species is among continents irregular (we can divide them into two groups - Australia with Europe and North America and South America with Africa and Asia), I tested the abovementioned relationships at both - global and continental scale. Species richness of native species increased with NPP, precipitation and temperature and decreased with the difference in temperature. The global distribution of non-native plants increased with precipitation and temperature velocity and decreases with temperature and precipitation velocity, although the results varied for particular continents. Unlike other studies the number of non-native species didn't correlate with the number of native plant species. Concurrently...

The mangrove forest is an ecosystem distributed worldwide along tropical andsubtropical coastlines. The environmental conditions are known to affect species distributionpatterns, and to understand them is one of the main goals of biogeography. The association ofenvironmental factors (e.g. temperature and precipitation) and species distribution patterns haschallenged scientists since long. Species are distributed in a geographical space, however, whyspecies are present in a certain location but absent in another is a fundamental question inbiogeography. This PhD thesis aims at better understanding the most intriguing issues relatedto the role of environmental factors associated with mangrove distribution range limits andspecies richness from regional (Brazilian mangroves) to global scales.For the Brazilian mangroves, two scales were used to comprehend the spatial ecological nicheof mangrove tree species. First, the entire Brazilian mangrove-lined coast was considered, andseveral environmental variables were used to explain what is driving mangrove tree speciesdistribution. Second, a detailed analysis of daily Sea Surface Temperature (SST) data for theBrazilian mangrove forest at the southernmost mangrove range limit was done, and comparedwith a site beyond the range limit. The chilling events of SST data, also considering oceancurrents, show that Laguncularia racemosa is probably bounded by the southernmost Brazilianmangrove limit because of a dispersal constraint rather than by the frequency of chillingevents. However, the abundance of L. racemosa in Laguna at the Southern mangrove rangelimit, compared with only a few individuals of A. schaueriana, is probably associated with thechilling events of SST constituting a constraint to the latter species. This proves that mangroverange limits are not explained by a single causeThis PhD thesis also has the objective to evaluate the influence of upwelling intensity onthe distribution worldwide, which is its approach at a global scale. The sea surface temperature(SST) had been identified as one of the key drivers of global mangrove distribution, given thecoincidence of isotherms with mangrove global limits. However, other factors play a role in thevariability of SST. Cold waters from deep ocean layers rise to the surface (upwelling systems),which reduces SST values and can trigger aridity. Although previous research has confirmedthat mangrove distribution is driven by a variety of factors, this PhD thesis additionallydemonstrates a significant influence of upwelling intensity, and hence provides elements for abetter understanding of the factors driving mangrove expansion/retraction at a global scale. Inaddition, this work emphasizes climate and oceanographic processes influencing mangroverange limits. While contributing to a better understanding of some of the most intriguingquestions on the macroecology of mangrove, this PhD thesis also raises new questions thatshould be studied by future research. / Doctorat en Sciences / info:eu-repo/semantics/nonPublished

Eastern Sand Darter (Ammocrypta pellucida) is listed as Threatened under the Canadian Species at Risk Act. Canadian populations are declining primarily due to the siltation of sandy depositional areas, the preferred habitat of the species. Little other relevant biological information is available for most Canadian populations and only limited information is available for populations in the United States. To supplement the paucity of information, this study collected biological information on A. pellucida during field surveys in 2006- 2007 from 10 sites located around the Big Bend Conservation Area in the lower Thames River, Ontario, Canada. Collected data were used to estimate critical life history traits including: longevity, fecundity, clutch size and number, growth, survival, age-at-first-maturity and cohort age structure. Longevity was 3+ years, with age-at-first-maturity being 1+ for both sexes. A minimum of 2 clutches, were laid per year with an average clutch size of 71 eggs. Average density within in the study area was 0.36 ± 0.11 A. pellucida/m². Quantitative comparison of lower Thames River biological information with a more southerly A. pellucida population in the Little Muskingum River, Ohio, demonstrated little latitudinal variation between the populations. Data comparison suggests that localized environmental factors are affecting biological characteristics, in particular water temperature that may be controlled by differences in riparian cover and/or groundwater input. Field derived life history information was used to create a Leslie matrix model which was used for population viability analysis. Perturbation analyses of reproductive scenarios involving changes in clutch numbers and size and age-at-first maturity found large variations in the finite rate of population growth. Elasticity analyses further indicated that 0+ survival and 1+ fertility were the limiting life history parameters. Thus allowing fish to survive until first reproduction would have the largest overall impact on improving population viability. Inclusion of environmental stochasticity in the model facilitated estimation of extinction probabilities in the range of 0.13 to 0.21 within 100 years. Based on the above, it is recommended that management activities for protection and restoration of A. pellucida focus on habitat protection of nursery and spawning areas.

Eastern Sand Darter (Ammocrypta pellucida) is listed as Threatened under the Canadian Species at Risk Act. Canadian populations are declining primarily due to the siltation of sandy depositional areas, the preferred habitat of the species. Little other relevant biological information is available for most Canadian populations and only limited information is available for populations in the United States. To supplement the paucity of information, this study collected biological information on A. pellucida during field surveys in 2006- 2007 from 10 sites located around the Big Bend Conservation Area in the lower Thames River, Ontario, Canada. Collected data were used to estimate critical life history traits including: longevity, fecundity, clutch size and number, growth, survival, age-at-first-maturity and cohort age structure. Longevity was 3+ years, with age-at-first-maturity being 1+ for both sexes. A minimum of 2 clutches, were laid per year with an average clutch size of 71 eggs. Average density within in the study area was 0.36 ± 0.11 A. pellucida/m². Quantitative comparison of lower Thames River biological information with a more southerly A. pellucida population in the Little Muskingum River, Ohio, demonstrated little latitudinal variation between the populations. Data comparison suggests that localized environmental factors are affecting biological characteristics, in particular water temperature that may be controlled by differences in riparian cover and/or groundwater input. Field derived life history information was used to create a Leslie matrix model which was used for population viability analysis. Perturbation analyses of reproductive scenarios involving changes in clutch numbers and size and age-at-first maturity found large variations in the finite rate of population growth. Elasticity analyses further indicated that 0+ survival and 1+ fertility were the limiting life history parameters. Thus allowing fish to survive until first reproduction would have the largest overall impact on improving population viability. Inclusion of environmental stochasticity in the model facilitated estimation of extinction probabilities in the range of 0.13 to 0.21 within 100 years. Based on the above, it is recommended that management activities for protection and restoration of A. pellucida focus on habitat protection of nursery and spawning areas.