Drivers of parasite β-diversity among anuran hosts depend on scale, realm and parasite group

Abstract

A robust understanding of what drives parasite β-diversity is an essential step towards explaining what limits pathogens' geographical spread. We used a novel global dataset (latitude −39.8 to 61.05 and longitude −117.84 to 151.49) on helminths of anurans to investigate how the relative roles of climate, host composition and spatial distance to parasite β-diversity vary with spatial scale (global, Nearctic and Neotropical), parasite group (nematodes and trematodes) and host taxonomic subset (family). We found that spatial distance is the most important driver of parasite β-diversity at the global scale. Additionally, we showed that the relative effects of climate concerning distance increase at the regional scale when compared with the global scale and that trematodes are generally more responsive to climate than nematodes. Unlike previous studies done at the regional scale, we did not find an effect of host composition on parasite β-diversity. Our study presents a new contribution to parasite macroecological theory, evidencing spatial and taxonomic contingencies of parasite β-diversity patterns, which are related to the zoogeographical realm and host taxonomic subset, respectively. This article is part of the theme issue ‘Infectious disease macroecology: parasite diversity and dynamics across the globe’.

Infectious disease macroecology: parasite diversity and dynamics across the globe

“…[49,[119][120][121]) could be used to accelerate macroecological exploration of mutualistic networks and other understudied organismal systems. More importantly, findings presented in our issue highlight the need to look beyond the availability of their symbiotic partners and suggest that a deep understanding of the climatic niche of symbionts themselves is crucial for predicting their future distributions under global change [45,56,80].…”

“…Martins et al [56] examine parasite beta-diversity and compare the effects of host distribution, environmental variation and spatial scale in an integrative framework. Beta-diversity reflects compositional change among local communities and regional assemblages, and thus links patterns of diversity at different spatial scales (Anderson et al [57]).…”

“…As the discipline of disease macroecology continues to mature, emphasis has also begun to shift from documenting patterns to exploring the mechanisms that drive them (e.g. [56,87,90]), that is from 'what?' to 'why?'.…”

“…Although parasites must rely on their hosts to complete their reproductive cycles [40,41], the diversity and distribution of parasites at large scale are constrained by both their hosts and the external environmental condition (e.g. Poulin [45]; Martins et al [56]). Therefore, parasitic organisms and free-living organisms are alike in the sense that their macroecological patterns are governed by complex processes, with both abiotic and biotic forces acting in concert to drive their diversity and distribution dynamics.…”

Phanerozoic parasitism and marine metazoan diversity: dilution versus amplification

“…They reviewed the evidence for mechanisms through which community diversity and structure could influence disease, including parasite decoys, predators and low competency hosts. Though the generality of the dilution hypothesis is still debated [53][54][55][56][57], this negative relationship between parasitism and diversity seems especially clear in cases of biodiversity loss [58] but it is likely a scale-dependent phenomenon as are many other patterns [59,60]. At larger spatial scales of observation, one can find evidence for a positive relationship between diversity and parasitism [61,62].…”