Variation in habitat connectivity generates positive correlations between species and genetic diversity in a metacommunity

Abstract

An increasing number of studies are simultaneously investigating species diversity (SD) and genetic diversity (GD) in the same systems, looking for 'species- genetic diversity correlations' (SGDCs). From negative to positive SGDCs have been reported, but studies have generally not quantified the processes underlying these correlations. They were also mostly conducted at large biogeographical scales or in recently degraded habitats. Such correlations have not been looked for in natural networks of connected habitat fragments (metacommunities), and the underlying processes remain elusive in most systems. We investigated these issues by studying freshwater snails in a pond network in Guadeloupe (Lesser Antilles). We recorded SD and habitat characteristics in 232 ponds and assessed GD in 75 populations of two species. Strongly significant and positive SGDCs were detected in both species. Based on a decomposition of SGDC as a function of variance-covariance of habitat characteristics, we showed that connectivity (opportunity of water flow between a site and the nearest watershed during the rainy season) has the strongest contribution on SGDCs. More connective sites received both more alleles and more species through immigration resulting in both higher GD and higher SD. Other habitat characteristics did not contribute, or contributed negatively, to SGDCs. This is true of the desiccation frequency of ponds during the dry season, presumably because species markedly differ in their ability to tolerate desiccation. Our study shows that variation in environmental characteristics of habitat patches can promote SGDCs at metacommunity scale when the studied species respond homogeneously to these environmental characteristics.

Spatial mismatches between plant biodiversity facets and evolutionary legacy in the vicinity of a major Mediterranean city

“…For example, Davis et al (2008), who investigated mammal diversity, and Kraft et al (2010), who focused on plant diversity, demonstrate some spatial discrepancies between simple counts of endemic species richness and ongoing diversification within the California biodiversity hotspot. Other recent studies report robust links between the genetic and specific components of biodiversity (e.g., He et al, 2008;Papadopoulou et al, 2011;Lamy et al, 2013) and support the existence of surrogates of genetic diversity under certain conditions and scales. These results emphasise that, for system-based conservation planning (Whittaker et al, 2005;Rodrigues and Brooks, 2007), and to better understand the future of biodiversity under global change (Lee and Jetz, 2008), we need to improve our knowledge of the relevance and consistency of putative links between the different components of biodiversity.…”

“…As previously shown by Lamy et al (2013) correlations analyses between species and genetic diversities should be conducted at the relevant spatial and temporal scales. Our results are demonstrating that coarse scale studies of biodiversity will overlook evolutionary legacy as well as crucial areas for long-term persistence.…”

Positive relationship between genetic- and species diversity on limestone outcrops in the Carpathian Mountains

“…While in oceanic island systems area/heterogeneity and isolation may be prime drivers of diversity, in mainland islands additional factors such as the matrix effect (Cook et al, 2002) and climate-driven habitat contractions and expansions (Puş caş et al, 2008) further complicate the interpretation of biological patterns. Although there is accumulating theoretical and empirical support for similarity between oceanic and mainland island systems (Vellend, 2003;Vellend and Geber, 2005;Wehenkel et al, 2006;Sei et al, 2009;Lamy et al, 2013), nonsignificant (Puş caş et al, 2008;Taberlet et al, 2012) and negative (Silvertown et al, 2009;Fady and Conord, 2010) correlations have also been reported. An important source of these contradictory results is the lack of a clear outline of the history of fragmentation and extent of habitat isolation, despite readily available frameworks (Watson, 2002).…”

Parallel effects of environmental properties on genetic diversity and species diversity

“…群落中的均匀程度 (Whittaker, 1972) (Vellend, 2003(Vellend, , 2004Struebig et al, 2011;Wei & Jiang, 2012;Lamy et al, 2013 Fig. 1 A theoretical model which depict the parallel effects of environmental properties on genetic diversity and species diversity (refer to Vellend & Geber, 2005) 表1 不同生态过程对遗传多样性与物种多样性的平行效应(参考Vellend和Geber, 2005) Table 1 The parallel effects of different ecological processes on genetic diversity and species diversity (refer to Vellend & Geber, 2005) Fig.…”