Humidity levels drive reproductive modes and phylogenetic diversity of amphibians in the Brazilian Atlantic Forest

Abstract

Aim The diversity of reproductive modes among amphibians constitutes a striking example of how differences in the biology of species provide important explanations for species distribution patterns on a broad scale. We hypothesize that sites with a higher humidity level will support more modes of reproduction than drier sites and will consequently exhibit a higher phylogenetic diversity. Furthermore, if there is a gradient in the tolerance of reproductive modes to desiccation, there will be a nested pattern in the composition of reproductive modes among sites. Location Twenty‐seven forest sites in the Brazilian Atlantic Forest. Methods Through a path analysis approach, we evaluated the direct and indirect effects of the humidity level on the number of reproductive modes, as well as the relative importance of both variables on amphibian phylogenetic diversity. A nestedness analysis was used to quantify the extent to which the compositions of both species and reproductive modes in drier sites correspond to subsets of those in sites with higher annual precipitation. Results We found that the reproductive modes present in drier sites are non‐random subsets of those present in sites with higher humidity levels. Because reproductive modes are phylogenetically conserved among amphibians, sites with a greater number of reproductive modes supported greater phylogenetic diversity. Sites with high precipitation throughout the year provided suitable environmental conditions for a larger number of reproductive modes, whereas sites with low precipitation and typical seasonal climates supported only those reproductive modes specialized to resist desiccation. Main conclusions Our results show that humidity‐related variables are key environmental factors related to both the richness of reproductive modes and phylogenetic diversity. Our results support the hypothesis that the higher phylogenetic diversity found in moister sites reflects differences in the tolerance to desiccation among different reproductive modes. Given that reproductive modes are associated with susceptibility to desiccation, their incorporation into explanatory models may trigger a significant advance in the understanding of the mechanisms regulating the species richness and composition of amphibian communities.

Anurans of the Agudos and Jaú municipalities, state of São Paulo, Southeastern Brazil

“…This discrepancy is a result of several interrelated factors, such as topography, altitude, rainfall, humidity and temperature (Rossa-Feres et al 2011;Haddad et al 2013). According to Silva et al (2012), regions with strong seasonal climates support only those reproductive modes that are resistant to the desiccation of eggs, thus reducing the phylogenetic diversity of the given region. The low rainfall recorded for nearly nine months of the year in the inland areas of the state of São Paulo provides few survival opportunities for groups with complex reproductive modes, which is reflected in the lower diversity of this region.…”

Reproductive biology of a bromeligenous frog endemic to the Atlantic Forest: Aparasphenodon arapapa Pimenta, Napoli and Haddad, 2009 (Anura: Hylidae)

“…Furthermore, additional attention has been dedicated to specific reproductive modes since they respond differently to habitat disturbance and deserve a different conservation approach. As pointed out by Loyola et al (2008) and Silva et al (2012) conservation assessments for the Atlantic Forest should include aspects of amphibian life history. Aparasphenodon arapapa is an endemic species from the Atlantic Forest, with a specific and rare reproductive mode and its populations and conservation status deserve attention.…”

The utility of open-access biodiversity information in representing anurans in the Brazilian Atlantic Forest and Cerrado

“…The highest density of occurrence records within the AF and CER is in southeastern Brazil (mainly in the state of São Paulo), and doubtless is a result of a recent initiative to advance the biodiversity knowledge of the state of São Paulo, with an increase in anuran surveys (the Biota-FAPESP Program, see Rossa-Feres et al 2011). The vouchers from most of the anuran inventories supported by this program were deposited in herpetological collections that are hosted in the SpeciesLink database (e.g., Vasconcelos and Rossa-Feres 2005, Santos et al 2007, 2009, Zina et al 2007, Silva et al 2012. Although other areas of Atlantic Forest have enough point records to be considered minimally represented, this is clearly not the case for anurans in the CER.…”