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Almoussawi, A., Lenoir, J., Jamoneau, A., Hattab, T., Wasof, S., Gallet-Moron, E., et al. (2019). Forest fragmentation shapes the alpha-gamma relationship in plant diversity. J. Veg. Sci., .
Résumé: Questions Forest fragmentation affects biodiversity locally (alpha diversity) and beyond – at relatively larger scales (gamma diversity) – by increasing dispersal and recruitment limitations. Yet, does an increase in fragmentation affect the relationship between alpha and gamma diversity and what can we learn from it? Location Northern France. Methods We surveyed 116 forest patches across three fragmentation levels: none (continuous forest); intermediate (forest patches connected by hedgerows); and high (isolated forest patches). Plant species richness of both forest specialists and generalists was surveyed at five nested spatial resolutions across each forest patch: 1 m(2); 10 m(2); 100 m(2); 1,000 m(2); and total forest patch area. First, we ran log-ratio models to quantify the alpha-gamma relationship. We did that separately for all possible combinations of fragmentation level (none vs intermediate vs high) x spatial scale (e.g., alpha-1 m(2) vs gamma-10 m(2)) x species type (e.g., alpha-specialists vs gamma-specialists). We then used linear mixed-effects models to analyze the effect of fragmentation level, spatial scale, species type and all two-way interaction terms on the slope coefficient extracted from all log-ratio models. Results We found an interaction effect between fragmentation level and species type, such that forest specialists shifted from a linear (i.e., proportional sampling) to a curvilinear plateau (i.e., community saturation) relationship at low and high fragmentation, respectively, while generalists shifted from a curvilinear to a linear pattern. Conclusions The impact of forest fragmentation on the alpha-gamma relationship supports generalist species persistence over forest specialists, with contrasting mechanisms for these two guilds. As fragmentation increases, forest specialists shift from proportional sampling towards community saturation, thus reducing alpha diversity likely due to dispersal limitation. Contrariwise, generalists shift from community saturation towards proportional sampling, thus increasing alpha diversity likely due to an increase in the edge:core ratio. To ensure long-term conservation of forest specialists, one single large forest patch should be preferred over several small ones.
Mots-Clés: agricultural landscapes; alpha diversity; anthropogenic disturbances; assemblages; community assembly; community patterns; competition; connectivity; dispersal limitations; gamma diversity; habitat conservation strategies; habitat fragmentation; local-regional richness relationship; metacommunity dynamics; regional species richness; relative importance; saturation; specialists; succession
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Alves-Junior, F. D. A., Leitao Camara De Araujo, M. D. S., Bertrand, A., & Souza-Filho, J. F. (2016). First report of two deep-sea shrimps of the genus Acanthephyra A. Milne-Edwards, 1881 (Crustacea: Decapoda: Acanthephyridae) from southwestern Atlantic. Zootaxa, 4184(1), 193–200.
Résumé: This paper reports two deep-sea shrimps, Acanthephyra acanthitelsonis and A. armata from southwestern Atlantic waters. The samples were collected in two different moments, the first in the Potiguar Basin, northeast of Brazil (03/05 degrees S; 38/35 degrees W), covering the states of Rio Grande do Norte (RN) and Ceare (CE) in the year of 2011, and afterward on Rocas Atoll, located in the state of Rio Grande do Norte (RN) (3 degrees 51' S, 033 degrees 49' W; 3 degrees 52' S, 033 degrees 47' W) in the year of 2015. The occurrence of A. acanthitelsonis on Rocas Atoll and A. armata found along the continental slope in the Potiguar Basin, comprising both species, which were recorded for the first time in the southwestern Atlantic. This paper increases the number of Acanthephyra species recorded in Brazilian waters up to six and adds to our knowledge and distribution of deepsea fauna in the south Atlantic.
Mots-Clés: Acanthephyridae; assemblage; caridea; gulf-of-mexico; New Records; northeastern Brazil; Potiguar Basin; ridge; Rocas Atoll; south; zone
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Barnagaud, J. - Y., Kissling, W. D., Tsirogiannis, C., Fisikopoulos, V., Villeger, S., Sekercioglu, C. H., et al. (2017). Biogeographical, environmental and anthropogenic determinants of global patterns in bird taxonomic and trait turnover. Glob. Ecol. Biogeogr., 26(10), 1190–1200.
Résumé: AimTo assess contemporary and historical determinants of taxonomic and ecological trait turnover in birds worldwide. We tested whether taxonomic and trait turnover (1) are structured by regional bioclimatic conditions, (2) increase in relationship with topographic heterogeneity and environmental turnover and change according to current and historical environmental conditions, and (3) decrease with human impact. Major TaxaBirds. LocationGlobal. MethodsWe used computationally efficient algorithms to map the taxonomic and trait turnover of 8,040 terrestrial bird assemblages worldwide, based on a grid with 110km x 110 km resolution overlaid on the extent-of-occurrence maps of 7,964 bird species, and nine ecological traits reflecting six key aspects of bird ecology (diet, habitat use, thermal preference, migration, dispersal and body size). We used quantile regression and model selection to quantify the influence of biomes, environment (temperature, precipitation, altitudinal range, net primary productivity, Quaternary temperature and precipitation change) and human impact (human influence index) on bird turnover. ResultsBird taxonomic and trait turnover were highest in the north African deserts and boreal biomes. In the tropics, taxonomic turnover tended to be higher, but trait turnover was lower than in other biomes. Taxonomic and trait turnover exhibited markedly different or even opposing relationships with climatic and topographic gradients, but at their upper quantiles both types of turnover decreased with increasing human influence. Main conclusionsThe influence of regional, environmental and anthropogenic factors differ between bird taxonomic and trait turnover, consistent with an imprint of niche conservatism, environmental filtering and topographic barriers on bird regional assemblages. Human influence on these patterns is pervasive and demonstrates global biotic homogenization at a macroecological scale.
Mots-Clés: Anthropocene; Beta diversity; Beta-diversity; biogeographical legacies; biotic homogenization; climate changes; community; components; dispersal; functional diversity; functional diversity; life-history traits; mammal assemblages; net primary production; regional assemblages; specialization; species richness
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Bender, M. G., Pie, M. R., Rezende, E. L., Mouillot, D., & Floeter, S. R. (2013). Biogeographic, historical and environmental influences on the taxonomic and functional structure of Atlantic reef fish assemblages. Global Ecology and Biogeography, 22(11), 1173–1182.
Résumé: Aim To disentangle how historic, biogeographic and environmental factors have shaped the composition of different reef fish assemblages, we analysed assemblage structure from a taxonomic (proportions of species from different families) and functional perspective (diet and body size). Location Atlantic Ocean. Methods The distributions of 1629 fish species were compiled for 31 locations across the Atlantic Ocean (39°66′ N, 27°50′ S). These locations provide a richness gradient ranging from 54 species in St Paul's Rocks to 474 in Cuba. We used cluster analyses to assess how historical and biogeographic factors have shaped the taxonomic and functional structure (i.e. the distribution of species within families, diet and body size groups) of assemblages. We then employed a constrained analysis of principal coordinates (CAP) to test the relative influence of the distance from the biodiversity centre in the Atlantic, sea surface temperature, isolation, coral species richness and area, and coastal length on the observed patterns of assemblage structure. Results The taxonomic and functional structure of reef fish assemblages across the Atlantic exhibits a biogeographic fingerprint, with a marked discrimination between species-rich biogenic reefs (concentrated primarily in the Caribbean and composed of small species feeding on invertebrates) and poorer peripheral regions dominated by larger species with more diverse diets. The first CAP axis explains 87% of body size distribution in assemblages, showing that the effects of sea surface temperature and coral richness and those of isolation are antagonistic and can be embedded into a single dimension. Environmental factors, such as temperature and habitat complexity, explain the disproportionate number of small species in the Caribbean, whereas in the remaining regions the predominance of large-bodied fish increases with isolation due to high dispersal ability. Main conclusions We found that historical events, which have shaped the biogeography of reef fishes, and environmental characteristics (coral reefs versus periphery) have both played a role in structuring the taxonomic and functional components of Atlantic fish assemblages.
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Benedetti, F., Ayata, S. - D., Irisson, J. - O., Adloff, F., & Guilhaumon, F. (2019). Climate change may have minor impact on zooplankton functional diversity in the Mediterranean Sea. Divers. Distrib., 25(4), 568–581.
Résumé: Aim To assess the impact of climate change on the functional diversity of marine zooplankton communities. Location The Mediterranean Sea. Methods We used the functional traits and geographic distributions of 106 copepod species to estimate the zooplankton functional diversity of Mediterranean surface assemblages for the 1965-1994 and 2069-2098 periods. Multiple environmental niche models were trained at the global scale to project the species habitat suitability in the Mediterranean Sea and assess their sensitivity to climate change predicted by several scenarios. Simultaneously, the species traits were used to compute a functional dendrogram from which we identified seven functional groups and estimated functional diversity through Faith's index. We compared the measured functional diversity to the one originated from null models to test if changes in functional diversity were solely driven by changes in species richness. Results All but three of the 106 species presented range contractions of varying intensity. A relatively low decrease of species richness (-7.42 on average) is predicted for 97% of the basin, with higher losses in the eastern regions. Relative sensitivity to climate change is not clustered in functional space and does not significantly vary across the seven copepod functional groups defined. Changes in functional diversity follow the same pattern and are not different from those that can be expected from changes in richness alone. Main conclusions Climate change is not expected to alter copepod functional traits distribution in the Mediterranean Sea, as the most and the least sensitive species are functionally redundant. Such redundancy should buffer the loss of ecosystem functions in Mediterranean zooplankton assemblages induced by climate change. Because the most negatively impacted species are affiliated to temperate regimes and share Atlantic biogeographic origins, our results are in line with the hypothesis of increasingly more tropical Mediterranean communities.
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