Spread dynamics of invasive species

Abstract

Species invasions are a principal component of global change, causing large losses in biodiversity as well as economic damage. Invasion theory attempts to understand and predict invasion success and patterns of spread. However, there is no consensus regarding which species or community attributes enhance invader success or explain spread dynamics. Experimental and theoretical studies suggest that regulation of spread dynamics is possible; however, the conditions for its existence have not yet been empirically demonstrated. If invasion spread is a regulated process, the structure that accounts for this regulation will be a main determinant of invasion dynamics. Here we explore the existence of regulation underlying changes in the rate of new site colonization. We employ concepts and analytical tools from the study of abundance dynamics and show that spread dynamics are, in fact, regulated processes and that the regulation structure is notably consistent among invasions occurring in widely different contexts. We base our conclusions on the analysis of the spread dynamics of 30 species invasions, including birds, amphibians, fish, invertebrates, plants, and a virus, all of which exhibited similar regulation structures. In contrast to current beliefs that species invasions are idiosyncratic phenomena, here we provide evidence that general patterns do indeed exist.conservation ͉ invasion ͉ population dynamics ͉ range expansion ͉ regulation

The response of plant community diversity to alien invasion: evidence from a sand dune time series

“…A final third phase follows in which aliens have no or only little further areal expansion (Pyšek and Hulme 2005). Thus, alien populations can persist in relatively low numbers for decades before exploding, after various ecological and evolutionary processes have come into play, and then enter a chronic phase (Arim et al 2006;Strayer et al 2006) in which the probability of invasion increases with time after their introduction (residence time). All of the recorded species were introduced, either accidentally or voluntarily, after 1500 and can, accordingly, be classified as neophytes (CelestiGrapow et al 2009(CelestiGrapow et al , 2010bPyšek et al 2004).…”

Potential dispersal mechanisms of the cryptogenic anemone, Anemonia alicemartinae

“…This corresponds well with the observations of Rivadeneira & Oliva (2001) who described anemones as semi-sessile organisms that can only move relatively short distances. The establishment of individuals at new sites depends on several factors, including genetic variability, body size, abundance, local adaptation abilities and physical tolerance (Arim et al 2006). According to our fi ndings, the behavior of Anemonia alicemartinae may be a dispersal strategy which could explain its establishment success on the coast of Chile.…”

Distribution and spread of the invasive slug Arion vulgaris Moquin-Tandon in Norway

“…Single records might only reveal spreading of this species in the year of sampling and we do not know if it will be found the following years. Observations suggest that A. vulgaris follows a typical pattern of an invasive species with an explosion in density a few years after being introduced into a new area, followed by a stabilisation period when density flattens out (Shigesada & Kawasaki 1997;Arim et al 200�).…”