Aquatic pollution increases the relative success of invasive species

Abstract

Although individual ecosystems vary greatly in the degree to which they have been invaded by exotic species, it has remained difficult to isolate mechanisms influencing invader success. One largely anecdotal observation is that polluted or degraded areas will accumulate more invaders than less-impacted sites. However, the role of abiotic factors alone in influencing invisibility has been difficult to isolate, often because the supply of potential invaders is confounded with conditions thought to increase vulnerability to invasion. Here, we conducted a field experiment to test how the assemblages of exotic versus native marine invertebrates changed during community assembly under different exposure levels of a common pollutant, copper. The experiment was conducted by deploying fouling panels in a Randomized Block Design in San Francisco Bay. Panels were periodically removed, placed into buckets with differing copper concentrations, and returned to the field after 3 days. This design allowed propagule availability to the plates to be statistically independent of short-term copper exposure. The results demonstrate that copper caused significant differences in community structure. Average native species richness was significantly affected by copper exposure, but average exotic richness was not. The total native species pool within treatments exhibited a greater than 40% decline within increasing copper, while the exotic species pool did not change significantly. These results confirm that anthropogenic alteration of abiotic factors influences invader success, indicating that management strategies to reduce invader impacts should include both efforts to improve environmental conditions as well as reduce invader supply.

Is <em>Fundulus heteroclitus</em> Intrusion Depleting Winter Marsh Pools of Native Fish Species?

“…Also, these ecosystems have experienced degradation caused by climatic changes, namely high temperatures and low precipitation [8]. The completion of the Alqueva dam located 150 km from the Guadiana River 2 of 16 mouth promoted a reduction in freshwater inflow leading to the degradation of salt marsh vegetation in the lower Guadiana estuary [9]. Moreover, climate change scenarios, predict for this region an increase in temperature, length, and frequency of dry periods [8].…”

“…In the Guadiana estuary, a community shift has been already documented, including plankton and fish [9,11,12]. In addition, first occurrences of several marine invasive species have also been recorded, with potentially detrimental effects on native biota [13].…”

An introduced Polychaete in South America - Ecologic Affinities of Manayunkia speciosa (Polychaeta, Sabellidae) and the Oligochaetes of Uruguay River, Argentina

“…Polluted areas could accumulate a higher quantity of invasive species than the less impacted areas (Crooks et al, 2011). Freshwater ecosystems are particularly affected by biological invasions.…”

“…The anthropogenic alteration of the abiotic factors (pollution, physic disturbances, artificial navigation routes, etc.) facilitates biological invasions (Crooks et al, 2011;Gabel et al, 2011). Estuaries, coastal lagoons and inner waters generally present more species of introduced invertebrates than the marine environments (Zaiko et al, 2011).…”

Pressão de propágulos ou distúrbios? Decifrando os determinantes da invasão por cachorros na Mata Atlântica

“…Dado o grande número de casos de invasões de espécies, que ocorrem em uma variedade enorme de circunstâncias específicas, há evidências na literatura de que várias dessas hipóteses possam explicar a invasão em pelo menos algum grau em alguma circunstância (Catford et al, 2009). Ainda assim, algumas hipóteses têm sido rotineiramente corroboradas em diferentes grupos e ambientes, principalmente aquelas relacionadas à pressão de propágulos (Lockwood et al, 2005;Colautti et al, 2006;Simberloff, 2009; 2013) e aquelas associadas ao papel dos distúrbios no ambiente (Byers, 2002;Crooks et al, 2011;Jauni et al, 2015;Gantchoff & Belant, 2015).…”