When can efforts to control nuisance and invasive species backfire?

Department of Natural Resources, Cornell University, Ithaca, New York 14853, USA.
Ecological Applications (Impact Factor: 4.13). 09/2009; 19(6):1585-95. DOI: 10.1890/08-1467.1
Source: PubMed

ABSTRACT Population control through harvest has the potential to reduce the abundance of nuisance and invasive species. However, demographic structure and density-dependent processes can confound removal efforts and lead to undesirable consequences, such as overcompensation (an increase in abundance in response to harvest) and instability (population cycling or chaos). Recent empirical studies have demonstrated the potential for increased mortality (such as that caused by harvest) to lead to overcompensation and instability in plant, insect, and fish populations. We developed a general population model with juvenile and adult stages to help determine the conditions under which control harvest efforts can produce unintended outcomes. Analytical and simulation analyses of the model demonstrated that the potential for overcompensation as a result of harvest was significant for species with high fecundity, even when annual stage-specific survivorship values were fairly low. Population instability as a result of harvest occurred less frequently and was only possible with harvest strategies that targeted adults when both fecundity and adult survivorship were high. We considered these results in conjunction with current literature on nuisance and invasive species to propose general guidelines for assessing the risks associated with control harvest based on life history characteristics of target populations. Our results suggest that species with high per capita fecundity (over discrete breeding periods), short juvenile stages, and fairly constant survivorship rates are most likely to respond undesirably to harvest. It is difficult to determine the extent to which overcompensation and instability could occur during real-world removal efforts, and more empirical removal studies should be undertaken to evaluate population-level responses to control harvests. Nevertheless, our results identify key issues that have been seldom acknowledged and are potentially generic across taxa.

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Available from: Elise F Zipkin, Feb 26, 2015
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    • "Marine invertebrates provide interesting models to study the genetics of invasion biology because they can spread rapidly due to their high fecundities and lifestages that allow for long range dispersal (Gilg et al. 2010). High fecundity is a characteristic trait of successful invasive species, allowing the invader to overcome diminished population sizes (Kolar and Lodge 2001; Zipkin et al. 2009). In addition, the ability to disperse over long distances is often understudied with regard to the spread of invasive species across the globe (Suarez et al. 2001; Gaylord et al. 2002). "
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    ABSTRACT: The goal of this study was to investigate the phylogeny, invasion history and genetic structure of the global invader Megabalanus coccopoma. First, we created a Bayesian phylogeny using cytochrome oxidase I and 16S mitochondrial genes of samples we collected and sequences available on GenBank for all species in the genus Megabalanus. Second, we compared the genetic differences within and between native and invasive populations verified as M. coccopoma by constructing a haplotype network of the COI sequences and estimating gene diversity (h) and nucleotide diversity (π). Finally, we ran an analysis of molecular variance and calculated pairwise ΦST to evaluate the similarity among populations. We identified several lineages that correspond to putatively different species of Megabalanus and uncovered nomenclature discrepancies among GenBank samples and undocumented lineages from our own collections. However, we found that the majority of samples were indeed M. coccopoma. Among populations of M. coccopoma, levels of within-population genetic diversity were not significantly different (ph = 0.131, pπ = 0.129) between native (h = 0.970, π = 0.00708) and non-native populations (h = 0.950, π = 0.00605) and analysis of molecular variance analyses revealed that 98.34 % of the genetic variation was partitioned within populations with a significant global ΦST = 0.017. Our results revealed that invasions in at least the southeastern United States and Brazil are composed of multiple lineages; however, we found that most of the global invasion occurred from a single lineage, M. coccopoma, and that no significant genetic differentiation exists between native and non-native populations of this species.
    Biological Invasions 08/2014; 16(8). DOI:10.1007/s10530-013-0624-7 · 2.72 Impact Factor
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    • "Harvest may even increase overall density (overcompensation; e.g., Jonze´n and Lundberg 1999, Zipkin et al. 2009). Compensation and overcompensation have been observed in many pest species (e.g., Buckley et al. 2001, Jonze´n et al. 2002, Zipkin et al. 2008, Pardini et al. 2009) and may underlie the persistence of invasive populations under management. "
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    ABSTRACT: The population effects of harvest depend on complex interactions between density dependence, seasonality, stage structure, and management timing. Here we present a periodic nonlinear matrix population model that incorporates seasonal density dependence with stage-selective and seasonally selective harvest. To this model, we apply newly developed perturbation analyses to determine how population densities respond to changes in harvest and demographic parameters. We use the model to examine the effects of popular control strategies and demographic perturbations on the invasive weed garlic mustard (Alliaria petiolata). We find that seasonality is a major factor in harvest outcomes, because population dynamics may depend significantly on both the season of management and the season of observation. Strategies that reduce densities in one season can drive increases in another, with strategies giving positive sensitivities of density in the target seasons leading to compensatory effects that invasive species managers should avoid. Conversely, demographic parameters to which density is very elastic (e.g., seeding survival, second-year rosette spring survival, and the flowering to fruiting adult transition for maximum summer densities) may indicate promising management targets.
    Ecological Applications 12/2013; 23(8):1893-905. DOI:10.1890/12-1712.1 · 4.13 Impact Factor
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    • "The outcome of species invasions may depend upon initial conditions, such as the number of invasive propagules (Lockwood et al. 2005) or the state of the invaded community (Case 1990). Finally, restoring communities to pre-invasion states is often impossible, even when the invasive is reduced to extremely low numbers (e.g., Cox and Allen 2008, Zipkin et al. 2009, Firn et al. 2010), suggesting the possibility of hysteresis. Rusty crayfish (Orconectes rusticus) are an invasive species capable of producing rapid transitions in ecosystems, sometimes across multiple trophic levels (Lodge et al. 1994, Wilson et al. 2004). "
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