The impact of native competitors on an alien invasive: Temporal niche shifts to avoid interspecific aggression?

Wildlife Conservation Research Unit, Department of Zoology, University of Oxford, Tubney House, Abingdon Road, Tubney, Oxford OX135QL, UK.
Ecology (Impact Factor: 4.66). 06/2009; 90(5):1207-16. DOI: 10.1890/08-0302.1
Source: PubMed


The American mink, Neovison vison, is an established, alien invasive species in the United Kingdom that originally colonized the country at a time when two native mustelids (otters, Lutra lutra, and polecats, Mustela putorius) were largely absent. Both of these species are now recovering their populations nationally. We compared the relative abundance and the behavior of mink in the 1990s and in the 2000s in an area of southern England where both otters and polecats were absent in the 1990s but reappeared in the intervening years. We found that mink were still abundant in the 2000s in the presence of otters and polecats, but that they appeared to have altered some aspects of their behavior. In accordance with previous studies, we found that mink consumed fewer fish in the presence of otters. We also found that mink were predominantly nocturnal in the 1990s (in the absence of competitors) but were predominantly diurnal in the 2000s (in the presence of competitors). We hypothesize that this temporal shift may be an avoidance mechanism allowing the coexistence of mink with the otter and the polecat, although we are unable to attribute the shift to one or the other species. We also found that mink in the presence of competitors weighed less but remained the same size, suggesting the possibility of a competitor-mediated decline in overall body condition. This is one of very few field studies demonstrating a complete temporal shift in apparent response to competitors. The implications of this study are that recovering otter populations may not lead to significant and long-term reductions in the number of invasive mink in the United Kingdom as has been suggested in the media, although we cannot exclude the possibility of a decline in mink in the longer-term.

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Available from: Michael D.F. Thom, Dec 21, 2013
    • "Biotic interactions have been long known to influence establishment success of alien species (Py sek & Prach, 1993;Lloret et al., 2005;Harrington et al., 2009). Nevertheless, this issue Figure 3Gaussian kernel displaying relationships between species richness and taxonomic distinctness in source and recipient areas for (a) Lithobates catesbeianus and (b) Rhinella marina. "
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    ABSTRACT: Aim Invasive species present negative impacts on native biodiversity at a global scale. A key goal of community ecology is to identify what drives invasiveness, but hypotheses relying on biotic mechanisms remain largely untested for many groups. Here we asked whether source and recipient communities of two highly successful invasive anurans (the bullfrog Lithobates catesbeianus and the cane toad Rhinellla marina) differ consistently from a taxonomic and/or functional standpoint. If affirmative, this pattern could suggest that taxonomic and/or functional distances between an invasive species and a potentially recipient community might influence the alien’s invasive potential. Location World-wide. Methods Based on co-occurrence data of 1061 amphibian species, we compared 30 source to 30 recipient communities of bullfrogs and cane toads by means of biotic metrics that summarize taxonomic and functional diversity and the relative position of the invasive species within the community. We also included environmental drivers that reportedly influence invasibility (climate, resource availability, spatial heterogeneity, and propagule pressure). Results Both invasive species were functionally distant to their respective recipient communities; in contrast, community diversity did not explain much variation between source and recipient communities. Climate matching possibly influenced cane toad’s but not bullfrog’s invasiveness, and landscape factors had little relevance overall. Main conclusion This study advances the notion that the relative position of a recently introduced species within the native functional space may help predicting its invasive potential.
    No preview · Article · Jan 2016 · Diversity and Distributions
    • "Such animals may shift their activity patterns to avoid or reduce the risk of predation (Fenn and Macdonald 1995; Fraser et al. 2004), or extent of interference competition for resources by other species (Valeix et al. 2007; Harrington et al. 2009). Temporal partitioning is one way a species can differentiate their ecological niche (Schoener 1974; Kronfeld-Schor and Dayan 2003), avoid predation risk, and coexist with other animals (Fenn and Macdonald 1995; Harrington et al. 2009)—the basis of the " risk allocation hypothesis " (Lima and Bednekoff 1999; Beauchamp and Ruxton 2011). For many species, temporal niche adjustment is also an advantageous strategy for avoiding high levels of human disturbance (Schwartz et al. 2010). "
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    ABSTRACT: Activity patterns of wildlife are often associated with the risk of predation, foraging requirements, and impacts of anthropogenic disturbance. Animals may adjust their temporal niche by shifting their activity patterns in relation to anthropogenic disturbance activities; however, few studies have recorded this response. We investigated the extent to which disturbances associated with pastoralism changed the timing of foraging and activity patterns of Himalayan marmot, a widely distributed rodent that inhabits alpine meadows in the mountains of central Asia. Using a scan-sampling observational approach, we collected data from 30 marmot sites in the Upper Mustang region of Annapurna Conservation Area, Nepal. We developed an index of pastoralism intensity for each site, based on the presence of livestock, herders, guard dogs, distance from pastoralist camps, and density of major tracks. Using this index, marmot time spent above-ground, and foraging distance from burrows, was compared between high and low pastoralism sites. Using a linear mixed modeling approach, there was no significant difference between areas of high and low pastoralism in either the total daily activity time or foraging distance from burrows. However, marmots adjusted their diurnal patterns of activity and the distances moved from their burrows in relation to the timing of pastoralist activities (temporal niche shift). In areas experiencing high levels of pastoralism, marmots were less active during periods of herding activity, and compensated by increasing activity when herding activity was less. By changing foraging behaviors, any increase in pastoralism may have significant consequences in terms of marmot population viability.
    No preview · Article · Jun 2015 · Behavioral Ecology
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    • "Smaller predators can adjust their activity and movements to reduce the risk of interspecific encounters with larger, dominant ones (e.g. Durant, 1998; Harrington et al., 2009; Vanak et al., 2013). Seidensticker (1976) and Karanth & Sunquist (2000) suggested an extensive temporal overlap of activity between tigers and common leopards, which do not support temporal partitioning between these cats (but see Steinmetz et al., 2013). "

    Full-text · Dataset · Jan 2015
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