Maintenance of tree phylogenetic diversity in a highly fragmented rain forest

Abstract

Summary1. Deforestation and forest fragmentation can drive species to local extinction, potentially changing the phylogenetic community structure and diversity of remaining assemblages. We tested this hypothesis analysing a large vegetation data set from a highly fragmented rain forest. 2. We assessed 9000 trees (both saplings and adults) from 268 species in 45 rain forest patches (ranging from < 1 to 700 ha) in three landscapes with different deforestation levels (4%, 11%, and 24% forest cover) in Los Tuxtlas, Mexico. We tested whether species density (i.e. number of species per unit area) and phylogenetic structure and diversity differed among landscapes, whether they were related to patch area, and whether the relationships differed among landscapes. 3. Overall, the observed differences in sapling and adult species densities across forest patches and landscapes (e.g. lower species densities in smaller patches) resulted in few and very weak changes in the phylogenetic community structure and diversity. Our results indicate that local extirpation of tree species may occur randomly or uniformly (but not in a clustered manner) throughout the phylogenetic tree, supporting the hypothesis of low phylogenetic conservatism of traits associated with vulnerability to forest fragmentation in the Neotropics. 4. Synthesis. This study indicates that in highly deforested and fragmented rain forests, the local extirpation of tree species does not occur across entire lineages. These novel and hopeful findings have direct implications for the ecology and conservation of fragmented rain forests. The maintenance of phylogenetic diversity in highly fragmented landscapes suggests that ecosystem function and stability may be maintained despite the loss of a number of tree species. We argue that in this unique Neotropical region, both large and small rain forest patches are critical for conserving regional tree evolutionary history.

Community assembly after long-term fragmentation: a case study of tropical rainforest in Xishuangbanna, south-west China

“…The phylogenetic distance between co-existing species changed to be more phylogenetically distant as indicated by the higher MPD and lower MNND in 2008. Our result is congruent with a study which showed that forest fragment can still maintain high phylogenetic diversity (Arroyo-Rodríguez et al 2012), though this is a temporal phenomenon.…”

“…Local climatic conditions in the fragmented rainforest usually change slowly towards being relatively drier (Li et al 2000), which adversely affects primary rainforest species (Zhu et al 2010). Research on forest fragmentation has become a major focus worldwide (Henle et al 2004;Safi et al 2011;Arroyo-Rodríguez et al 2012;Habel and Zachos 2012). Some researchers found decreased biodiversity in forest fragments (Hautier et al 2009;Goddard et al 2010;Safi et al 2011), while others indicated that a large proportion of biodiversity was maintained in fragmented tropical landscapes (ArroyoRodríguez and Toledo-Aceves 2009;Fahrig et al 2011;Arroyo-Rodríguez et al 2012).…”

Evolutionary heritage influences Amazon tree ecology

“…These results also indicate that changes in environmental conditions or disturbance regimes that favour particular life-history strategies will ultimately erode evolutionary diversity [54,55], although the presence of some convergent evolution across lineages may prevent significant loss of phylogenetic diversity over some scales of anthropogenic disturbance [56]. Our results may therefore help to resolve why different studies of the effect of disturbance on phylogenetic diversity have obtained contrasting results [54–56]: in particular, this study suggests that investigating the PS of traits that influence species ability to persist after disturbance within the species pool of interest will be critical to understand how disturbance will alter phylogenetic diversity. Finally, our results also suggest that any long-term changes in the evolutionary diversity of intact Amazonian forests may indicate functional shifts in these diverse ecosystems.…”

The assembly of tropical tree communities – the advances and shortcomings of phylogenetic and functional trait analyses

“…Accordingly several recent studies have investigated the phylogenetic dispersion of trees in these re-assembling communities (Letcher 2010, Letcher et al 2011, Arroyo-Rodriguez et al 2012, Ding et al 2012, Norden et al 2012, Whitfi eld et al 2012. Given their dynamic nature and their increasing dominance in tropical landscapes, secondary forests are therefore some of the best laboratories for studying tropical tree community assembly.…”