Natural abiotic factors more than anthropogenic perturbation shape the invasion of Eastern Mosquitofish (Gambusia holbrooki)

Abstract

Eastern Mosquitofish (Gambusia holbrooki) is an invasive and globally widespread species that is considered highly tolerant. We used species distribution models (SDMs) to assess factors, including the role of anthropogenic perturbation, that mediate its invasion on a regional scale. A better understanding of the important large-scale factors may help us identify future areas of concern and potential avenues for control. We built SDMs from presence records and randomly selected pseudo-absences of mosquitofish on a 10-× 10-km grid. We used 10 modeling techniques implemented in the biomod2 software and ensemble forecasts. Final models contained 12 environmental predictors, including natural environmental factors (elevation, slope, topographic index, precipitation, accumulated flow, temperature mean and range) and anthropogenic perturbation indicators (population density, urban and agricultural land uses, number of local and upstream dams). Elevation, temperature, and accumulated flow most strongly influenced mosquitofish distribution, and mosquitofish were found more frequently in downstream, warmer waters. Anthropogenic features, except the number of upstream dams, were poorer predictors of mosquitofish presence than were natural environmental factors. The best models suggested that mosquitofish are more likely to occur in areas with more dams upstream, but removing this predictor did not strongly affect model results. Restoration efforts or modifications to anthropogenic features appear unlikely to alter mosquitofish distribution patterns, highlighting the importance of preventing introductions to new areas. Mosquitofish have been extensively documented in the Iberian Peninsula, but consensus methods suggest many additional suitable areas from which records were not found. Thus, this highly invasive species is or may become much more widely distributed than current observations in the region.

Effects of size and sex on swimming performance and metabolism of invasive mosquitofish Gambusia holbrooki

“…These results support the idea that the invasive success of mosquitofish is partly explained by water flow and hydrological alteration (Meffe 1984;Murphy et al 2015). In freshwater ecosystems, abiotic factors (such as water quality, substrate composition and flow regime) are considered to be important predictors of ecosystem invasibility (Marchetti et al 2004;Lapointe et al 2012;Murphy et al 2015). In freshwater ecosystems, abiotic factors (such as water quality, substrate composition and flow regime) are considered to be important predictors of ecosystem invasibility (Marchetti et al 2004;Lapointe et al 2012;Murphy et al 2015).…”

“…These findings were more clearly observed in females, which certainly display more variability in body shape and have a wider mass range (Plaut 2002). These results support the idea that the invasive success of mosquitofish is partly explained by water flow and hydrological alteration (Meffe 1984;Murphy et al 2015). These results support the idea that the invasive success of mosquitofish is partly explained by water flow and hydrological alteration (Meffe 1984;Murphy et al 2015).…”

“…Mosquitofish are small-bodied fish, inhabiting the water-column and surface microhabitats. Water resource development and non-native species have been demonstrated as primary drivers in the decline of native fishes in lotic habitats, and decreasing water flows in rivers and streams due to dam construction and water extraction can facilitate invasion by mosquitofishes (Murphy et al 2015;Pool & Olden 2015). The mosquitofish is highly invasive despite its poor swimming capacity, which may be compensated by behavioural adaptations (e.g.…”

“…Oxygen consumption measurements are generally used to estimate metabolic rates (Bell & Terhune 1970;Price et al 2012), whereas critical swimming speed is a standard measurement for evaluating the swimming capabilities of fish (Plaut 2001). The eastern mosquitofish is a so-called 'limnophilic' species, and water flow is known to affect its invasive success (Benejam et al2010;Murphy et al 2015). Multiple autoecological aspects have been assessed for mosquitofish in the Iberian Peninsula, such as salinity tolerance, life-history traits, habitat requirements, parasite interactions, aggressive behaviour or prey selection (Garc ıa-Berthou 1999; Alcaraz & Garc ıa-Berthou 2007a; Benejam et al 2009;Carmona-Catot et al 2013Magellan & Garc ıa-Berthou 2016).…”

“…survival, feeding, mating or predator avoidance), particularly in studies of fish as an integral part of aquatic ecosystems (Plaut 2001;Killen et al 2007;Huang et al 2013). Furthermore, this information could be used to identify potential target areas for invasion under fluctuating hydrological conditions (Murphy et al 2015), which may have implications for water management (e.g. Ward et al 2003).…”