Not everything is everywhere: the distance decay of similarity in a marine host–parasite system

Aim We investigated how the spatial distribution of parasites, measured as either their geographical range size or their frequency of occurrence among localities, relates to either their average local abundance or the variance in their abundance among localities where they occur. Location We used data on the abundance of 46 metazoan parasite species in 66 populations of threespine sticklebacks, Gasterosteus aculeatus, from Europe and North America. Methods For each parasite species, frequency of occurrence was calculated as the proportion of stickleback populations in which it occurred, and geographical range size as the area within the smallest possible polygon delimited using the coordinates of the localities where it occurred. Generalized linear models were used to assess how these two measures of spatial distribution were influenced by several predictor variables: geographical region (North America or Europe), life cycle (simple or complex), average local abundance, the coefficient of variation in abundance across localities, and median prevalence (proportion of infected hosts within a locality). Results Our analyses uncovered four patterns. First, parasites in North America tend to have higher frequencies of occurrence among surveyed localities, but not broader geographical ranges, than those in Europe. Second, parasite species with simple life cycles have wider geographical ranges than those with complex cycles. Third, there was a positive relationship between average abundance of the different parasite species and their frequency of occurrence, but not between average abundance and geographical range size. Fourth, the coefficient of variation in abundance covaried positively with both the frequency of occurrence and geographical range size across the different parasite species. Thus, all else being equal, parasites showing greater site‐to‐site variability in abundance occur in a greater proportion of localities and over a broader geographical area than those with a more stable abundance among sites. Main conclusions Local infection patterns are linked with large‐scale distributional patterns in fish parasites, independently of host effects, such that local commonness translates into regional commonness. The mechanisms linking parasite success at both scales remain unclear, but may include those that maintain the continuum between specialist and generalist parasites. Regardless, the observed patterns have implications for the predicted changes in the geographical distributions of many parasites in response to climate change.

show abstract

“…, 1996; Cone et al. , 2004; Pérez‐del‐Olmo et al. , 2009) and of a study on avian malaria (Szöllösi et al.…”

Section: Discussionmentioning

confidence: 99%

Scaling up from epidemiology to biogeography: local infection patterns predict geographical distribution in fish parasites

Poulin

Blanar

Thieltges

et al. 2011

Journal of Biogeography

View full text Add to dashboard Cite

show abstract

“…Like other assemblages, parasite communities in any given host species show a clear decay in compositional similarity as a function of the distance separating them: nearby host populations tend to have many parasite species in common, whereas distant ones share very few. This phenomenon applies to varying degrees to a wide range of host and parasite taxa [81][82][83][84][85][86]. Several mechanisms can act, alone or in combination, to produce a decrease of the similarity in species composition between two communities with increasing distance between them [87].…”

Section: Host Dispersal and Distance Decay Of Similaritymentioning

confidence: 99%

The comparative ecology and biogeography of parasites

Poulin

Krasnov

Mouillot

et al. 2011

Phil. Trans. R. Soc. B

View full text Add to dashboard Cite

Comparative ecology uses interspecific relationships among traits, while accounting for the phylogenetic non-independence of species, to uncover general evolutionary processes. Applied to biogeographic questions, it can be a powerful tool to explain the spatial distribution of organisms. Here, we review how comparative methods can elucidate biogeographic patterns and processes, using analyses of distributional data on parasites (fleas and helminths) as case studies. Methods exist to detect phylogenetic signals, i.e. the degree of phylogenetic dependence of a given character, and either to control for these signals in statistical analyses of interspecific data, or to measure their contribution to variance. Parasite-host interactions present a special case, as a given trait may be a parasite trait, a host trait or a property of the coevolved association rather than of one participant only. For some analyses, it is therefore necessary to correct simultaneously for both parasite phylogeny and host phylogeny, or to evaluate which has the greatest influence on trait expression. Using comparative approaches, we show that two fundamental properties of parasites, their niche breadth, i.e. host specificity, and the nature of their life cycle, can explain interspecific and latitudinal variation in the sizes of their geographical ranges, or rates of distance decay in the similarity of parasite communities. These findings illustrate the ways in which phylogenetically based comparative methods can contribute to biogeographic research.

show abstract

“…While a number of empirical analyses have firmly established exponential decay (Nekola and White 1999, Qian et al 2005, Jobe 2007, linear (Blanchette et al 2008, Perez-del-Olmo et al 2009) and power law (Harte et al 1999, Condit et al 2002, Green et al 2004) forms have also been documented. While a number of empirical analyses have firmly established exponential decay (Nekola and White 1999, Qian et al 2005, Jobe 2007, linear (Blanchette et al 2008, Perez-del-Olmo et al 2009) and power law (Harte et al 1999, Condit et al 2002, Green et al 2004) forms have also been documented.…”

mentioning

confidence: 99%

Scale dependency in the functional form of the distance decay relationship

Nekola

McGill

2014

Ecography

View full text Add to dashboard Cite

We examine a novel mathematical approach which posits that the decay of similarity in community composition with increasing distance (aka distance decay) can be modeled as the sum of individual species joint-probability vs distance relationships. Our model, supported by analyses of these curves from three datasets (North American breeding birds, North American taiga plants, and tropical forest trees), suggest that when sampling grain is large enough to avoid absences due to stochastic sampling effects, and/or sampling extent is large enough to generate species turnover through the deterministic crossing of environmental and/or geographical range limits, species joint-probability over increasing distance will generally exhibit exponential decay. However, at small scales where occurrence is driven more by stochastic sampling effects, species joint-probability curves exhibit a power-law decay form. Lacking a theoretical prediction of how individual species joint-probability relationships combine to generate community distance decay, we also performed a meta-analysis of 26 ecological and 4 human-system datasets, using non-linear regression to mean and quantile non-linear regression at tau  0.95 for linear, exponential, and power-law decay forms. These analyses demonstrate that the functional form of community distance decay -as shown by comparison of AIC ranks -is largely determined by observational scale, with power law decay prevailing within domains where the species pool remains constant, while exponential decay prevails at larger scales over which the species pool varies, paralleling the patterns predicted in our mathematical approach.

show abstract

Not everything is everywhere: the distance decay of similarity in a marine host–parasite system

Cited by 53 publications

References 24 publications

Scaling up from epidemiology to biogeography: local infection patterns predict geographical distribution in fish parasites

Scaling up from epidemiology to biogeography: local infection patterns predict geographical distribution in fish parasites

The comparative ecology and biogeography of parasites

Scale dependency in the functional form of the distance decay relationship

Contact Info

Product

Resources

About