Resident‐immigrant dichotomy matters for classifying wetland site groups and metacommunities

Abstract

Summary The fact that species have resident (autochthonous) or immigrant (allochthonous) status at any given locality may have strong implications for ecological analysis. We used wetlands and adult odonates as a model system to evaluate the resident‐immigrant dichotomy for two modes of community analysis: (1) grouping sites based on species compositional variation and (2) identifying metacommunity structure. We tested a hypothesis of gradient‐structured (non‐random) resident occurrence versus unstructured (random) immigrant occurrence in the metacommunity context and predicted the resident occurrence would more effectively partition community variation and produce stronger site groupings than total (resident + immigrant) occurrence. Site group classification after fractioning out resident occurrence consistently and in some cases dramatically outperformed total occurrence. Resident damselflies produced the strongest classifications, which we attribute to greater dispersal limitation, environmental sorting or both. As predicted only the resident occurrence led to identifiable metacommunity structures, primarily Clementsian‐style turnover. This suggests the resident occurrence is gradient‐driven with species responding similarly to abiotic filters, whereas immigrant occurrence is more opportunistic and random. The resident‐immigrant dichotomy appears to have strong influence on quantitative classification of sites and metacommunities, and species composition of resident adult damselflies is potentially useful for differentiating and indicating site groups of non‐forested freshwater wetlands.

Species residency status affects model selection and hypothesis testing in freshwater community ecology

“…This agrees with earlier findings of non-random resident versus random immigrant species occurrence within the meta-community context (Bried et al, 2015b) and helps to explain some structural patterns identified in that study. This agrees with earlier findings of non-random resident versus random immigrant species occurrence within the meta-community context (Bried et al, 2015b) and helps to explain some structural patterns identified in that study.…”

“…A resident species occurrence designation, as determined previously using the same data set (see Bried et al, 2015a), required >20 individuals during at least one survey, tenerals on at least two surveys or species detection (teneral or not) on at least four surveys, with some exceptions (see Bried et al, 2015b). A resident species occurrence designation, as determined previously using the same data set (see Bried et al, 2015a), required >20 individuals during at least one survey, tenerals on at least two surveys or species detection (teneral or not) on at least four surveys, with some exceptions (see Bried et al, 2015b).…”

“…As such, resident communities may show a decay of compositional similarity among sites, driven by decreasing environmental similarity and increasing dispersal limitation over geographic distance (Nekola & White, 1999;Siepielski & McPeek, 2013). The alternative could be random community patterns with no clear signature of structuring, as might be expected for immigrants (Bried et al, 2015b). The alternative could be random community patterns with no clear signature of structuring, as might be expected for immigrants (Bried et al, 2015b).…”

“…Species-level residency state, although often treated as taxonomically fixed according to dispersal mode (e.g. This multi-state occurrence is important (at least implicitly) in studying actively dispersed animals and may strongly influence ecological inference and applications (Bried et al, 2015b;Patten, Bried & Smith-Patten, 2015). This multi-state occurrence is important (at least implicitly) in studying actively dispersed animals and may strongly influence ecological inference and applications (Bried et al, 2015b;Patten, Bried & Smith-Patten, 2015).…”

“…For example, as a result of local adaptation or in situ experience during ontogeny, resident species occurrence is expected to create a more non-random community structure compared to immigrant species occurrence (Bried et al, 2015b). For example, as a result of local adaptation or in situ experience during ontogeny, resident species occurrence is expected to create a more non-random community structure compared to immigrant species occurrence (Bried et al, 2015b).…”