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Canopy height explains species richness in the largest clade of Neotropical lianas

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Meyer et al. (2019) – Global Ecology and Biogeography

Tall and structurally complex forests can provide ample habitat and niche space for climbing plants, supporting high liana species richness. We test to what extent canopy height (as proxy of 3D habitat structure), climate and soil interact to determine species richness in the largest clade of Neotropical lianas. We expect that the effect of canopy height on species richness is higher for lianas from closed tropical rainforests compared to riparian and savanna habitats. We used structural equation models to evaluate direct and indirect effects of canopy height, climate (temperature, precipitation and precipitation seasonality), and soil (cation exchange capacity and soil types) on overall Bignonieae species richness (339 liana species), as well as on species richness of lianas from forest, riparian and savanna habitats, respectively. We further performed multiple regression models with Moran’s eigenvector maps to account for spatial autocorrelation. Canopy height was a key driver of liana species richness, in addition to climate and soil. Both, overall species richness and forest species richness showed a strong positive relationship with canopy height whereas the relationship was less pronounced for riparian species. Richness of savanna species even decreased with increasing canopy height. Climate also explained a substantial proportion of variation in liana species richness whereas soil variables showed little explanatory power. The relationship between canopy height and liana species richness differs among habitats. While forest and riparian lianas probably benefit from physical support to reach the forest canopy to escape low light availability in the understory, a high light availability in open habitats and an increased risk of embolism of conductive vessels for lianas with long stems living in areas with high seasonality might explain the inverse relationship between species richness and canopy height in savannas.

www.doi.org/10.1111/geb.13004

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Meyer et al. (2019) - Global Ecology and Biogeography

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Effects of neutrality and productivity on mammal richness and evolutionary history in Australia

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Coelho et al. (2018) – Ecography

Explaining how heterogeneous spatial patterns of species diversity emerge is one of the most fascinating questions of biogeography. One of the great challenges is revealing the mechanistic effect of environmental variables on diversity. Correlative analyses indicate that productivity is associated with taxonomic, phylogenetic, and functional diversity of communities. Surprisingly, no unifying body of theory has been developed to understand the mechanism by which spatial variation of productivity affects the fundamental processes of biodiversity. Based on widely discussed verbal models in ecology about the effect of productivity on species diversity, we developed a spatially explicit neutral model that incorporates the effect of primary productivity on community size and confronted our model’s predictions with observed patterns of species richness and evolutionary history of Australian terrestrial mammals. The imposed restrictions on community size create larger populations in areas of high productivity, which increases community turnover and local speciation, and reduces extinction. The effect of productivity on community size modeled in our study causes a higher accumulation of species diversity in productive regions even in the absence of niche-based processes. However, such a simple model is not capable of reproducing spatial patterns of mammal evolutionary history in Australia, implying that more complex evolutionary mechanisms are involved. Our study demonstrates that the overall patterns of species richness can be directly explained by changes in community sizes along productivity gradients, supporting a major role of processes associated with energetic constraints in shaping diversity patterns.

www.doi.org/10.1111/ecog.03784

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Coelho et al. (2018) - Ecography

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Evolution of anuran foam nest: trait conservatism and lineage diversification

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Pereira et al. (2017) – Biological Journal of the Linnean Society

Key innovations are organismal traits that trigger adaptive radiation and lineage diversification. The wide range of anurans’ reproductive strategies from aquatic to terrestrial modes are potential key innovations. One such strategy is the foam nest, a structure with multiple functions that originated independently several times in distinct continents. Here we explore several evolutionary aspects associated with foam nest in multiple lineages to test the hypothesis that this trait is phylogenetically conserved and has influenced diversification. We used the most inclusive anuran phylogeny to date to reconstruct ancestral states, measure phylogenetic signal and evaluate models of trait-dependent diversification. Our results show that foam nest appeared during the Paleocene-Eocene transition (c. 55 Myr) in three major groups (Leptodactylidae, Limnodynastidae and Rhacophoridae) and has been highly conserved ever since. The foam nest probably originated from an ancestor with aquatic reproduction, except in Rhacophoridae, in which it evolved from an ancestor with jelly nests. Despite possessing several ecological functions, we only found evidence of foam nest influence on diversification rates in the South American lineage Leptodactylidae. We suggest that foam nest was an important adaptation for lineages to survive through historical climatic changes and to reproduce in dry open areas.

https://doi.org/10.1093/biolinnean/blx110

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Pereira et al. (2017) - BJLS

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Ancestral reconstruction of reproductive traits shows no tendency toward terrestriality in Leptodactyline frogs

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Pereira et al. (2015) – BMC Evolutionary Biology

Traditionally, the evolution of terrestrial reproduction in anurans from ancestors that bred in water has been accepted in the literature. Still, the existence of intermediate stages of water dependency, such as species that lay eggs close to water (e.g., in burrows) instead of in bodies of water, supports the hypothesis of an ordered and gradual evolution in the direction of a more terrestrial form of reproduction. However, this conventional view has recently been challenged by some anurans groups. Leptodactylinae frogs are a remarkable example of anurans with an outstanding diversity in terms of reproductive features, with distinct water dependency among lineages. Here, we tested the hypothesis of a gradual and ordered tendency towards terrestriality in Leptodactylinae, including the existence of obligatory intermediate stages, such as semi-terrestrial reproductive strategies. We also addressed the association between reproductive modes and morphological and ecological features. An ancestral reconstruction analysis indicated that even though shifts from aquatic to terrestrial breeding occurred throughout the history of Leptodactylus and Adenomera, shifts from terrestrial to aquatic reproduction happened at almost the same frequency. Our results also demonstrated that reproductive modes for semi-terrestrial tadpoles were not necessarily an intermediate form between aquatic and terrestrial breeds. Correlations among reproductive modes and other life-history traits suggested that tadpole environment, clutch size, nuptial spines, and egg pigmentation were co-evolving and driven by water dependency. Our results found no evidence of evolutionary tendencies toward terrestriality in Leptodactylinae. We found reversals from terrestrial to aquatic tadpole development and no evidence of obligatory intermediate stages, such as semi-terrestrial reproductive strategies. We also found correlations between reproductive modes and other life-history traits driven by water dependence. Aquatic reproductive modes are associated with higher clutch sizes, lentic waters, and the presence of nuptial spines and egg pigmentation.

www.doi.org/10.1186/s12862-015-0365-6

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Pereira et al. (2015) - BMC

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Anuran diversity (Amphibia) in recovered areas of mining activity in Cerrado and Eucalyptus urophylla planting in central Brazil

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Nomura et al. (2012) – Bioscience Journal

Amphibians diversity in the Cerrado is threatened mainly by the increase in human activities. Current legislation requires potentially impactful ventures to implement environmental programs that include the recovery of degraded areas and the study of ecological mechanisms associated with the recolonization of altered areas. The objectives of this study were: to evaluate possible differences in species composition in anuran assemblages between areas of modified topography (ATM) and areas of unmodified topography (ATNM); and to compare the species richness of anurans between ATM and ATNM. Despite the greater number of species recorded in ATM (28 species) compared to ATNM (22 species), there was no difference in richness when comparing rarefaction curves or estimated richness (jackknife1). However, the two assemblies differed in relative abundance curves, especially in terms of the pattern of the most abundant species. Locally, the co-occurrence analysis demonstrated that species in the ATM co-occur less than expected at random, which indicates the sharing of environments for reproduction mediated by competitive interactions. The presence of artificial water bodies with high structural heterogeneity, associated with forest fragments in good condition are factors that contribute to the maintenance of a high diversity of amphibians in the area.

https://seer.ufu.br/index.php/biosciencejournal/article/view/12278

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Nomura et al. (2012)

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