Patterns of parasite community dissimilarity: the significant role of land use and lack of distance‐decay in a bat–helminth system

Abstract

Increasing community dissimilarity across geographic distance has been described for a wide variety of organisms and understanding its underlying causes is key to understanding mechanisms driving patterns of biodiversity. Both niche‐based and neutral processes may produce a distance decay relationship; however, disentangling their relative influence requires simultaneous examination of multiple potential drivers. Parasites represent a unique opportunity in which to study distance decay because community dissimilarity may depend on environmental requirements and dispersal capability of parasites as well also those of their hosts. We used big brown bats Eptesicus fuscus and their intestinal helminths to investigate: 1) independent contributions of geographic and environmental distances on dissimilarity of intestinal helminth component communities between populations of big brown bats; 2) which environmental variables best explained variation in community dissimilarity; and 3) whether similar patterns of decay with geographic or environmental distance were observed for within‐host population and within‐individual host parasite communities. We used compositional measures of community dissimilarity to examine how parasite communities may change with geographic distance and varying environmental conditions. Non‐spatial variables strongly influenced compositional parasite community dissimilarity over multiple community scales, and we observed little evidence for spatial processes such as distance decay. Environment surrounding roost sites better predicted helminth community dissimilarity than any other class of variables and landcover classes representing anthropogenic modification consistently explained variation in community structure. Our results indicate that human disturbance drives significant patterns of parasite community dissimilarity, most likely by changing the presence or abundance of intermediate hosts in an area.

Compositional turnover in host and parasite communities does not change network structure

“…Distance-decay relationships are a common observation in both free-living (Soininen et al 2007, Korhonen et al 2010) and parasitic (Poulin 2003, Warburton et al 2016 communities. There are numerous reasons why we would expect helminth parasite communities to become dissimilar with increasing geographic distance.…”

“…Host-parasite networks offer an interesting test of distance-decay relationships, as they networks differ markedly from other types of networks in their interaction patterns (Poisot et al (2013)). Historically, host-parasite distancedecay relationships have largely been confined to examinations of relationships between host or parasite community turnover as a function of environmental or geographic distance (Oliva and Teresa González 2005, Thieltges et al 2009, Warburton et al 2016, or parasite community dissimilarity as a function of host traits or phylogenetic distance (Poulin 2010). Relating host and parasite dissimilarity to one another, Krasnov et al (2012) was the first, to our knowledge, to link the similarity of host communities to the similarity of parasite communities among geographic locations (but see Pellissier et al (2013) for a more recent example).…”

Climate, host phylogeny and the connectivity of host communities govern regional parasite assembly

“…A strong incentive exists to identify barriers to species establishment and determine how these barriers modulate invasion risk (Hoberg, ; Kelly, Paterson, Townsend, Poulin, & Tompkins, ; Springborn et al., ). For parasites, geographic barriers (such as distance or mountain ranges) are known to constrain species’ distributions (Brooks & Ferrao, ; Krasnov, Shenbrot, Khokhlova, & Degen, ; Lafferty, ; Warburton, Kohler, & Vonhof, ). In addition, environmental barriers (such as temperature and precipitation) drive development or transmission rates for many parasites, especially vector‐borne parasites such as those causing malaria and lyme disease (Epstein, ; Githeko, Lindsay, Confalonieri, & Patz, ; Patz, Campbell‐Lendrum, Holloway, & Foley, ).…”

“…A strong incentive exists to identify barriers to species establishment and determine how these barriers modulate invasion risk (Hoberg, 2010;Kelly, Paterson, Townsend, Poulin, & Tompkins, 2009;Springborn et al, 2015). For parasites, geographic barriers (such as distance or mountain ranges) are known to constrain species' distributions (Brooks & Ferrao, 2005;Krasnov, Shenbrot, Khokhlova, & Degen, 2016;Lafferty, 2009;Warburton, Kohler, & Vonhof, 2016).…”

Did biogeographical processes shape the monogenean community of butterflyfishes in the tropical Indo-west Pacific region?

“…Oliva and Gonzalez, 2005; Pérez 67 del Olmo et al, 2009;Timi et al, 2010). However, some studies have shown that other parameters 68 such as host phylogenetic distance or environmental conditions may play a more important role in 69 driving similarity of parasite communities than geographical distance (Vinarski et al, 2007; 70 Thieltges et al, 2010;Warburton et al, 2016). 71 5 In a recent study, Locke et al, (2012) showed that distance decay depends upon the 72 geographic scale of the study and latitude, being more significant further from the Equator.…”