Functional trait differences between native and invasive species across six habitats in the Czech Republic
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| Year of publication | 2016 |
| Type | Conference abstract |
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| Description | Invasive species may be invasive because they are similar to native species or alternatively they may be invasive by exploiting a separate niche. Here we investigate the relationship between plant invasion status (Native, Naturalized or Invasive) and species traits using a countrywide data from the Czech Republic. The data set contains 5950 species of which 4984 are classified as native, 784 are classified as naturalized (non-native but not spreading) and 182 are designated as invasive (non-native and spreading). Each species in the data set was matched with species level plant functional traits. We focused our analyses on three life history traits: height, specific leaf area (SLA) and germinule weight because these traits encapsulate three independent axes for plant life history evolution (Westoby 1998). The species data was further broken down into six unique habitats: grassland, ruderal, scree, wetland, scrub and forest. Our analysis of single traits indicated that invasive species were significantly different for both height and germinule weight in 5 of 6 habitats but for only 2 habitats for specific leaf area. The direction of the difference was only consistent for height data; when significant, invasive plants were taller than native plants. To examine life history strategies and potential trade-offs, we combined the trait data into a multi-dimensional niche index using non-metric multidimensional scaling (NMDS) and subsequently analyzed the distance between the native multi-dimensional trait index and the invasive multi-dimensional trait index using a cumulative density function that measured the distance of the invasive NMDS from the centroid of the native NMDS trait space. Using this more integrated measure, we find that five of six habitats show that the invasive species trait space occurs farther away from the center of the native species centroid trait distribution than expected by chance; further, the only non-significant habitat, wetlands, followed the pattern but was not statistically significant. Thus it appears that that invasive species occupy a multi-dimensional trait space at the outer edge of the native trait space trait space; this occurrence at the boundary of the niche space implies that invasive species are successful because they are beating the native species at their own game, rather than exploiting a unique strategy. |
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