Invaders are not a random selection of species

Abstract

We assembled information on 119 species of freshwater macroinvertebrate invaders in North America and Europe, and compared them to all native freshwater species in North America and Europe. We tested whether the invaders were a random or selected group among taxa (phylum or class), water quality requirements, and feeding habit. We found that freshwater macroinvertebrate invaders are not a random selection of species, and are overrepresented by molluscs and crustaceans, while taxa richness of native communities are dominated by insects. Over 35% of native species of aquatic invertebrates in North America are only able to live in areas with excellent or very good water quality, and are intolerant of organic pollution. In contrast, all invaders are tolerant of at least moderate amounts of organic pollution. There was a significant difference in the distribution of feeding habits between native species and invaders: collector-filterers (including suspension feeders) were 2.5-3 times more abundant, and predators were 3-4 times less abundant among invaders than among native invertebrates. The ongoing spread of exotic species affects the biodiversity of selected taxa, shifts communities toward greater tolerance of organic pollution and increases the numbers of suspension feeders, thereby enhancing benthic pelagic coupling in waterbodies with high densities of invaders. Because these processes are very similar in Europe and North America, we suggest that the observed patterns may have a common global effect.

Scale dependent effects of native prey diversity, prey biomass and natural disturbance on the invasion success of an exotic predator

“…For example, the invasive ladybird beetle, Coccinella septempunctata, will readily exploit alternative prey in alpha fields, when densities of their preferred aphid prey are low and native ladybirds have already dispersed (Evans 2004). Similar patterns have been found with many other invasive generalist predators, leading to the general notion that a broad generalist diet is a common trait contributing to invasion success (Karatayev et al 2009;Snyder and Evans 2006;Lodge 1993). As such the amount of prey as opposed to the diversity of prey may be a more important factor limiting the abundance of invasive crayfish predators as small scales.…”

The river Rhine: a global highway for dispersal of aquatic invasive species

“…These processes may be facilitated by colonization of groups of co-adapted invaders. Karatayev et al (2009) conclude that the ongoing spread of nonindigenous species not only affects biodiversity but also strongly shifts communities toward greater tolerance of organic pollution and increases the numbers of suspension feeders, thereby enhancing benthic pelagic coupling in aquatic ecosystems with high densities of invaders.…”

“…Biological trait analyses show that aquatic invaders in North America and Europe are not a random selection of species (Karatayev et al 2009). Invaders are over-represented by molluscs and crustaceans (mainly collector-filterers) and tolerate at least moderate amounts of organic pollution.…”

Recommendations on methods for the detection and control of biological pollution in marine coastal waters

“…Bioinvasion studies lack being more analytical and predictive because of uncertainties about vectors involved in the transportation process (Minchin, 2007a), numbers of established and spreading NIS, propagule pressure (Johnston et al, 2009), biological traits of invaders (Karatayev et al, 2009) and their environmental tolerance limits (Olyarnik et al, 2009), their functional role (Crooks, 2009) and the impacts on environment, economy and human health (Olenin et al, 2007).…”