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The Interplay between Environmental Filtering and Spatial Processes in Structuring Communities: The Case of Neotropical Snake Communities.

Cavalheri H, Both C, Martins M - PLoS ONE (2015)

Bottom Line: Such pattern suggests that the limited distribution of major snake lineages constrained species distributions.Structure indices for each community were also related to habitat type, showing that communities from non-forest areas tend to be more clustered.Our study showed that both environmental filtering and spatial gradients play important roles in shaping the composition of Neotropical snake communities.

View Article: PubMed Central - PubMed

Affiliation: Departamento de Ecologia, Instituto de Biociências, Universidade de São Paulo, 05508-090, São Paulo, SP, Brazil.

ABSTRACT
Both habitat filters and spatial processes can influence community structure. Space alone affects species immigration from the regional species pool, whereas habitat filters affect species distribution and inter-specific interactions. This study aimed to understand how the interplay between environmental and geographical processes influenced the structure of Neotropical snake communities in different habitat types. We selected six studies that sampled snakes in forests, four conducted in savannas and two in grasslands (the latter two are grouped in a non-forest category). We used the net relatedness and nearest taxon indices to assess phylogenetic structure within forest and non-forest areas. We also used the phylogenetic fuzzy-weighting algorithm to characterize phylogenetic structure across communities and the relation of phylogenetic composition patterns to habitat type, structure, and latitude. Finally, we tested for morphological trait convergence and phylogenetic niche conservatism using four forest and four non-forest areas for which morphological data were available. Community phylogenetic composition changed across forest and non-forest areas suggesting that environmental filtering influences community structure. Species traits were affected by habitat type, indicating convergence at the metacommunity level. Tail length, robustness, and number of ventral scales maximized community convergence among forest and non-forest areas. The observed patterns suggested environmental filtering, indicating that less vertically structured habitats represent a strong filter. Despite the fact that phylogenetic structure was not detected individually for each community, we observed a trend towards communities composed by more closely related species in higher latitudes and more overdispersed compositions in lower latitudes. Such pattern suggests that the limited distribution of major snake lineages constrained species distributions. Structure indices for each community were also related to habitat type, showing that communities from non-forest areas tend to be more clustered. Our study showed that both environmental filtering and spatial gradients play important roles in shaping the composition of Neotropical snake communities.

No MeSH data available.


Map of Brazil indicating snake communities studied.Background colors represent the biomes to which communities belong.
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pone.0127959.g001: Map of Brazil indicating snake communities studied.Background colors represent the biomes to which communities belong.

Mentions: We compiled a database of species composition for snake communities in Brazil using lists from published references in peer-reviewed journals and unpublished data provided by other researchers (S1 Table). In both cases, we used exclusively studies in which local species richness was well sampled (i.e., species accumulation curves reached, or were close to reaching, saturation). Data comprised communities from four major vegetation types, including forests (two communities from Amazon Forest and four from Atlantic Forest) and more open, less vertically structured vegetation types (herein referred to as non-forest areas) such as savannas and grasslands (four communities from Cerrado in central Brazil and two from Campos in the south; Table 1; Fig 1). We grouped these non-forest areas based on the similarity in composition of their snake faunas.


The Interplay between Environmental Filtering and Spatial Processes in Structuring Communities: The Case of Neotropical Snake Communities.

Cavalheri H, Both C, Martins M - PLoS ONE (2015)

Map of Brazil indicating snake communities studied.Background colors represent the biomes to which communities belong.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4465701&req=5

pone.0127959.g001: Map of Brazil indicating snake communities studied.Background colors represent the biomes to which communities belong.
Mentions: We compiled a database of species composition for snake communities in Brazil using lists from published references in peer-reviewed journals and unpublished data provided by other researchers (S1 Table). In both cases, we used exclusively studies in which local species richness was well sampled (i.e., species accumulation curves reached, or were close to reaching, saturation). Data comprised communities from four major vegetation types, including forests (two communities from Amazon Forest and four from Atlantic Forest) and more open, less vertically structured vegetation types (herein referred to as non-forest areas) such as savannas and grasslands (four communities from Cerrado in central Brazil and two from Campos in the south; Table 1; Fig 1). We grouped these non-forest areas based on the similarity in composition of their snake faunas.

Bottom Line: Such pattern suggests that the limited distribution of major snake lineages constrained species distributions.Structure indices for each community were also related to habitat type, showing that communities from non-forest areas tend to be more clustered.Our study showed that both environmental filtering and spatial gradients play important roles in shaping the composition of Neotropical snake communities.

View Article: PubMed Central - PubMed

Affiliation: Departamento de Ecologia, Instituto de Biociências, Universidade de São Paulo, 05508-090, São Paulo, SP, Brazil.

ABSTRACT
Both habitat filters and spatial processes can influence community structure. Space alone affects species immigration from the regional species pool, whereas habitat filters affect species distribution and inter-specific interactions. This study aimed to understand how the interplay between environmental and geographical processes influenced the structure of Neotropical snake communities in different habitat types. We selected six studies that sampled snakes in forests, four conducted in savannas and two in grasslands (the latter two are grouped in a non-forest category). We used the net relatedness and nearest taxon indices to assess phylogenetic structure within forest and non-forest areas. We also used the phylogenetic fuzzy-weighting algorithm to characterize phylogenetic structure across communities and the relation of phylogenetic composition patterns to habitat type, structure, and latitude. Finally, we tested for morphological trait convergence and phylogenetic niche conservatism using four forest and four non-forest areas for which morphological data were available. Community phylogenetic composition changed across forest and non-forest areas suggesting that environmental filtering influences community structure. Species traits were affected by habitat type, indicating convergence at the metacommunity level. Tail length, robustness, and number of ventral scales maximized community convergence among forest and non-forest areas. The observed patterns suggested environmental filtering, indicating that less vertically structured habitats represent a strong filter. Despite the fact that phylogenetic structure was not detected individually for each community, we observed a trend towards communities composed by more closely related species in higher latitudes and more overdispersed compositions in lower latitudes. Such pattern suggests that the limited distribution of major snake lineages constrained species distributions. Structure indices for each community were also related to habitat type, showing that communities from non-forest areas tend to be more clustered. Our study showed that both environmental filtering and spatial gradients play important roles in shaping the composition of Neotropical snake communities.

No MeSH data available.