A Source Area Approach Demonstrates Moderate Predictive Ability but Pronounced Variability of Invasive Species Traits

<div><p>The search for traits that make alien species invasive has mostly concentrated on comparing successful invaders and different comparison groups with respect to average trait values. By contrast, little attention has been paid to trait variability among invaders. Here, we combine an analysis of trait differences between invasive and non-invasive species with a comparison of multidimensional trait variability within these two species groups. We collected data on biological and distributional traits for 1402 species of the native, non-woody vascular plant flora of Austria. We then compared the subsets of species recorded and not recorded as invasive aliens anywhere in the world, respectively, first, with respect to the sampled traits using univariate and multiple regression models; and, second, with respect to their multidimensional trait diversity by calculating functional richness and dispersion metrics. Attributes related to competitiveness (strategy type, nitrogen indicator value), habitat use (agricultural and ruderal habitats, occurrence under the montane belt), and propagule pressure (frequency) were most closely associated with invasiveness. However, even the best multiple model, including interactions, only explained a moderate fraction of the differences in invasive success. In addition, multidimensional variability in trait space was even larger among invasive than among non-invasive species. This pronounced variability suggests that invasive success has a considerable idiosyncratic component and is probably highly context specific. We conclude that basing risk assessment protocols on species trait profiles will probably face hardly reducible uncertainties.</p></div

Comparison of functional diversity indices among Austrian plants that are either invasive or not invasive elsewhere in the world.

<p>Black triangles symbolize the diversity index values calculated for the group of the 305 invasive plants. The boxplots represent the range of index values calculated for 1000 equally large re-samples from the whole pool of 1402 native species with the bold lines indicating the 0.95 confidence interval of these re-sample based values. Panel (a) represents results for Functional Richness (defined by the volume of the functional space) and panel (b) results for Functional Dispersion (defined by the mean distance in multidimensional trait space of individual species to the centroid of all species), respectively. Label ‘all traits’ give results calculated with the total set of collected traits, label ‘invasive traits’ calculations based on traits that proved useful to distinguish invasive and non-invasive species in the preceding analyses.</p

Traits and trait groups used to explain invasiveness.

<p>Traits and trait groups used to explain invasiveness.</p

Best GLMM to explain invasiveness of Austrian non-woody vascular plants in other parts of the world.

<p>Best GLMM to explain invasiveness of Austrian non-woody vascular plants in other parts of the world.</p

MOESM2 of Effectiveness of management interventions for control of invasive Common ragweed Ambrosia artemisiifolia: a systematic review protocol

Additional file 2. Search comprehensiveness assessment

data_package.zip

<div>Data from the paper</div><div><b>Invasive alien pests threaten the carbon stored in Europe’s forests</b></div><div>by Rupert Seidl, Günther Klonner, Werner Rammer, Franz Essl, Adam Moreno, Mathias Neumann, and Stefan Dullinger</div><div>Nature Communications, 9, 2018.</div><div><br></div><div>https://www.nature.com/articles/s41467-018-04096-w<br></div><div>https://doi.org/10.1038/s41467-018-04096-w<br></div><div><br></div><div>The data set contains raster data (TIF format), see readme.txt for further details.</div

Data for Conti et al. 2017 JofEcol

Data for Conti et al. 2017 JofEco

Naturalizations have led to homogenization of the Malesian flora in the Anthropocene

Aim: Worldwide, floras are becoming homogenized at global scales, but regional patterns vary. Here, we present the first assessment for the Malesian phytogeographical region in terms of the timing of introductions, direction, magnitude and drivers of floristic change due to alien plant naturalizations.Location: Malesian phytogeographic region, including Southeast Asia and the Pacific.Taxon: Tracheophyta (vascular plants).Methods: We compiled data on first records of naturalized plants in Malesia to investigate temporal trends in the rate and origin of introductions. We then calculated β‐diversity (including turnover and nestedness) for the native, naturalized and Anthropocene (native + naturalized) floras for each pair of island groups (36 pairs), and a homogenization index for the native and Anthropocene floras, using presence/absence data for 31,580 plant species. Mantel tests were used to investigate the geographic, climatic and anthropogenic correlates of dissimilarity and homogenization.Results: Around 75% of all naturalized species documented to date were already reported for the first time within Malesia prior to 1950. This has led to homogenization between the historic (native) and contemporary (Anthropocene) floras for all island group pairs. Turnover was the most important process for driving compositional dissimilarity between island groups in Malesia in the native and Anthropocene floras, but homogenization resulted from decreases in nestedness and turnover. Differences in average taxonomic homogenization for island groups were associated with differences in their level of anthropogenic modification.Main Conclusions: This study improves current understanding of the direction and drivers of floristic homogenization in one of the world's most diverse tropical regions. Alien plant introductions carry a long historical legacy in Malesia, and naturalizations of these plants have led to overall taxonomic homogenization of the region's flora. Expected increases in the magnitude of human modification, without appropriate policy, will likely lead to further reductions in the floristic uniqueness of island groups.</p

The naturalized vascular flora of Malesia

Major regional gaps exist in the reporting and accessibility of naturalized plant species distribution data, especially within Southeast Asia. Here, we present the Malesian Naturalized Alien Flora database (MalNAF), the first standardized island-group level checklist of naturalized vascular plant species for the Malesian phytogeographical region. We used MalNAF to investigate the composition, origins, and habitat preferences of the naturalized flora. The naturalized vascular flora of Malesia consists of at least 1177 species. Richness is highest in the Philippines (539 spp.) and lowest in the Maluku Islands (87 spp.). But, the Lesser Sunda Islands had the highest naturalized species richness relative to native richness and Singapore has a higher naturalized plant species richness than would be expected given its size. When comparing the data for Malesia with a global dataset, we found that naturalized richness increased with area for islands but not for continental regions. Across the archipelago, 31 species are widespread, occurring in every island group, but the majority have a limited distribution of 2.4 ± 2.3 (mean ± SD) island groups per naturalized species. The naturalized plant species are representatives of 150 families, twenty of which are newly introduced to the region. Families richest in naturalized plant species in Malesia were Fabaceae (= Leguminosae) (160 spp.), Poaceae (= Gramineae) (138 spp.), and Asteraceae (= Compositae) (96 spp.). Most of these have a native range that includes tropical Asia, closely followed by those from Southern America (inclusive of the Caribbean, Central and South America), although at the island-group level, most have a higher proportion with a Southern American native range. Most naturalized species occur in anthropogenic habitats, but many are present in “natural” habitats with fewer species, such as Leucaena leucocephala, reported from specialized habitats like drylands. MalNAF provides a baseline for future studies of naturalized plant species distributions in the region.</p

Illustration of three country-level cases with different current land conditions and their potential for restoration and conservation.

(A) High proportion of large contiguous natural areas, (B) average global proportions, and (C) high proportion of shared areas plus cities and farms (see text). These cases are based on realistic examples of the average and of the spectrum of the three conditions across countries (naturebeyond2020.com/3conditions/; [13]). The shading illustrates the proportion of each condition. The proportion of degraded land ecosystems is shown in the lower patterned triangles. The area under protection by 2030 (Target 3) is shown in the upper yellow-dashed triangles (dispersed over shared and cities and farms categories to show the current reality, and representing 50%, 30%, and 10% of total area under protection in A, B, and C, respectively). Restoration of transformed to natural ecosystems by 2030 (Target 2 of the GBF) is shown by the green blobs spread across the degraded area (representing 20% of the degraded area in each case).</p