Influence of species invasion, seasonality, and connectivity on fish functional and taxonomic beta-diversity in a Neotropical floodplain (original) (raw)
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Frontiers in Environmental Science
An intensively debated issue in ecology is whether the variations in the biodiversity patterns of different biological groups are congruent in space and time. In addition, ecologists have recognized the necessity of accounting for both taxonomic and functional facets when analysing spatial and temporal congruence patterns. This study aimed to determine how the cross-taxon congruence of taxonomic and functional beta diversity varies across space and time, using data from four floodplains at a continental scale. Our general hypothesis was that the congruence between aquatic biological groups, either taxonomic or functional, would decrease with the “between-group” functional distance. Also, we examined how congruence patterns varied across spatial and temporal scales by focusing on how the cross-taxon relationships differ among Brazilian floodplains and between dry/wet periods. Our study comprised information on eight biological groups from the four largest Brazilian river-floodplain s...
Journal of Biogeography, 2020
Aim: Fish community composition is shaped by current and historical factors. In recently formed ecosystems, however, as the Quaternary coastal lagoons of South America, the influence of historical factors has less frequently been investigated. The low rate of endemism in these lagoons suggests a limited role for speciation while their dynamic formation history suggests local extinction and dispersal limitation could have affected present species composition. We aimed to assess the influence of past and current factors on the beta diversity of those communities and explore the main processes involved. Location: Atlantic coast of South America. Taxon: Fishes (173 species). Methods: We built a dataset of species occurrence in 129 lagoons across eight freshwater ecoregions of the world (FEOWs) located between latitudes 0° and 36°, and calculated beta diversity (β jac) and its turnover (β jtu) and nestedness (β jne) components. We used a partial Mantel test and multiple regressions on distance matrices to evaluate the importance of past and current factors, and of geographical distance in determining beta diversity. Past variables were those representing the historical freshwater habitat during the last glacial maximum (LGM), and contemporary variables were those related to current habitat. Results: We found high values of β jac within the FEOWs, with β jtu prevailing over β jne. Both past (palaeodrainage) and current (drainage area, salinity and lagoon area) factors affected species dissimilarity (β jac = 46%) and its components (β jtu = 44% and β jne = 20%), although explanation was, in part, shared with geographical distance. Individually, the influence of past factors was prevalent in beta diversity and its components. Main conclusions: The large influence of the past factors on beta diversity suggests that major changes in the availability of freshwater habitats and connectivity since the Pleistocene must have affected the colonization, extinction and recolonization processes of fishes along the eastern coast of South America. We suggest that the
PLoS ONE, 2012
The concept of b-diversity, defined as dissimilarity among communities, has been widely used to investigate biodiversity patterns and community assembly rules. However, in ecosystems with high taxonomic b-diversity, due to marked environmental gradients, the level of functional b-diversity among communities is largely overlooked while it may reveal processes shaping community structure. Here, decomposing biodiversity indices into a (local) and c (regional) components, we estimated taxonomic and functional b-diversity among tropical estuarine fish communities, through space and time. We found extremely low functional b-diversity values among fish communities (,1.5%) despite high dissimilarity in species composition and species dominance. Additionally, in contrast to the high a and c taxonomic diversities, a and c functional diversities were very close to the minimal value. These patterns were caused by two dominant functional groups which maintained a similar functional structure over space and time, despite the strong dissimilarity in taxonomic structure along environmental gradients. Our findings suggest that taxonomic and functional b-diversity deserve to be quantified simultaneously since these two facets can show contrasting patterns and the differences can in turn shed light on community assembly rules.
Navigating the multiple meanings of β diversity: a roadmap for the practicing ecologist
Ecology Letters, 2011
A recent increase in studies of b diversity has yielded a confusing array of concepts, measures and methods. Here, we provide a roadmap of the most widely used and ecologically relevant approaches for analysis through a series of mission statements. We distinguish two types of b diversity: directional turnover along a gradient vs. nondirectional variation. Different measures emphasize different properties of ecological data. Such properties include the degree of emphasis on presence ⁄ absence vs. relative abundance information and the inclusion vs. exclusion of joint absences. Judicious use of multiple measures in concert can uncover the underlying nature of patterns in b diversity for a given dataset. A case study of Indonesian coral assemblages shows the utility of a multi-faceted approach. We advocate careful consideration of relevant questions, matched by appropriate analyses. The rigorous application of null models will also help to reveal potential processes driving observed patterns in b diversity.
Hydrobiologia, 2011
This study evaluated whether the alpha and beta diversity of fishes in vegetated littoral zones of floodplain lakes in the Pantanal are randomly distributed on three different spatial scales: within the lake, among lakes, and between regions. Three alternative hypotheses were contrasted: (1) that regional diversity is generated at local scale, depending on the internal environmental heterogeneity of lakes, (2) that the diversity of fishes in floodplain lakes is produced at intermediate spatial scales, depending on structural differences and on the landscape matrix between lakes, and (3) that the diversity of fishes in the littoral zone is generated at regional scale, due to regional differences in land-use pattern and the presence of a geographical barrier represented by the river. Our results indicate that the regional diversity of fishes in the vegetated littoral zone of lakes in the northern Pantanal is a consequence of high diversity at the local level (a) and the wide differences in species composition among lakes and between regions. This suggests that we need to maintain environmental heterogeneity, represented by the structural differences among the lakes and their landscape matrix as well as regional differences in the flood pattern, if we hope to preserve the diversity of fishes in the region. Besides, it is necessary to establish new conservation units at the different Pantanal subregions, which should incorporate a set of lakes with different landscape features such as size, shape, and distance from and degree of connection to rivers.
Acta Scientiarum. Biological Sciences, 2015
We tested the hypothesis that the contribution of the nestedness component is higher in environments with more similar features (lentic or lotic), whereas the contribution of the turnover component is higher in environments with more dissimilar features (lotic vs. lentic). To this end, we partitioned beta diversity of the Oligochaeta community into 12 environments of the Upper Paraná River floodplain. We recorded 986 individuals of 17 taxa. Through Redundancy Analysis, we observed a differentiation between lentic and lotic habitats both by environmental features as species composition. Our hypothesis was partially supported, because in environments with more similar hydrological characteristics, we observed a greater contribution of the nestedness component only in lentic environments, whereas in lotic environments, the turnover component showed a higher value. Moreover, when analyzed the different environments (lentic vs. lotic), we noticed a very similar contribution of both components. Some species were more frequent, as A. pigueti and P. americana, while others were exclusive to some environments (N. bonettoi and H. aedeochaeta). We evidenced the importance of each component in structuring Oligochaeta community, nonetheless, in a different way between environments with more similar (nestedness to lentic and turnover to lotic) or dissimilar (almost the same contribution of both) features.
Programa de P os-graduac ßão em Sociedade, Tecnologia e Meio Ambiente, UniEvang elica, An apolis, Brazil SUMMARY 1. Understanding the relationships between different components of diversity is needed to improve conservation strategies for freshwater habitats. Here, we studied relationships between taxonomic and functional components of fish assemblages in 27 headwater and 22 main stem habitats of tropical streams in Central Brazil. 2. Using quantile regression analysis, we evaluated relationships between (i) taxonomic richness (S) and functional richness (FRic); (ii) taxonomic diversity (D + ) and functional diversity (MPD) and (iii) and taxonomic richness and functional diversity. 3. Taxonomic richness and diversity (S and D + ) were correlated with functional richness and diversity (FRic and MPD) in headwaters and main stems. However, relationships between taxonomic and functional components differed across habitat types within a catchment. Relationships between S and FRic and D + and MPD were stronger than those between S and MPD. 4. Combined, these findings imply that caution is advised when using one diversity component as a surrogate for another diversity component in studies directed towards the conservation of fishes in tropical headwaters and main stems. Moreover, conservation and management strategies must take account of habitat-specific relationships of the diversity components of fish assemblages when implementing management programmes.
Anais da Academia Brasileira de Ciências
Species distribution mapping methods have their advantages and limitations concerning their use on theoretical and/or applied macroecological approaches. However, it remains underexplored how the estimates of community ecology metrics vary across the distributions generated by different mapping methods. Here, we mapped the distribution patterns of the anuran beta diversity in the Atlantic Forest and Cerrado hotspots generated by three mapping methods: point-to-grid (PTG), extent-of-occurrence (EOO), and ecological niche modelling (ENM) maps, so we were able to compare the congruence of the local contribution to beta diversity index (LCBD) among them, as well as their turnover and nestedness components. PTGs generated the most divergent LCBD values probably due to the more resolved spatial scale in which species' presence are considered, so EEO and ENM generated similar beta diversity estimates for both hotspots. High LCBD values in the Cerrado were recorded in ecotone regions, whereas in the Atlantic Forest the highest beta diversity values were found along the Atlantic coast. The structure of beta diversity of PTG showed way too high values of importance for the turnover component compared to the EEO and ENM maps, which also recorded higher importance for the turnover than for the nestedness component.
Ecology and evolution, 2017
We partitioned the total beta diversity in the species composition of anuran tadpoles to evaluate if species replacement and nestedness components are congruent at different spatial resolutions in the Brazilian Atlantic Forest. We alternated the sampling grain and extent of the study area (among ponds at a site, among ponds within regions, among sites within regions, and among sites within regions pooled together) to assess the importance of anuran beta diversity components. We then performed variation partitioning to evaluate the congruence of environmental descriptors and geographical distance in explaining the spatial distribution of the species replacement and nestedness components. We found that species replacement was the main component of beta diversity, independent of the sampling grain and extent. Furthermore, when considering the same sampling grain and increasing the extent, the values of species replacement increased. On the other hand, when considering the same extent a...