Estimating costs and outcomes of invasive American mink (Neovison vison) management in continental areas: a framework for evidence based control and eradication

Abstract

Introduced predators are a major threat to biodiversity. While in island ecosystems the favoured management option is species eradication, in continental areas most managers tend to control-orientated options, assuming that eradication is an impossible goal. However, many management actions are conducted without precise or quantifiable goals, and their output is difficult to assess due to the lack of experimental approaches and scientific evidence. Here, we analyse the results of a typical small-scale short-term management action consisting of livetrapping and culling invasive American mink. We estimate the American mink population size at the beginning of the study assuming three different scenarios, assess the output of the management action in each scenario and model the results of further trapping efforts. Based on the results we estimate the effort and economic costs required for culling different population percentages per unit area, as well as the costs and feasibility of eradication. Our results provide a basis for planning invasive predator management, setting realistic management goals and estimating funding required, as well as a framework for managers to evaluate on-going management actions. In addition, our results suggest that American mink eradication from some continental areas would be feasible with current techniques at a moderate-low cost. We suggest that invasive predator management in continental areas should move towards eradication when feasible, regarding control as a second option.

The impact of river fragmentation on the population persistence of native and alien mink: an ecological trap for the endangered European mink

“…Despite the cost and effort of control/eradication projects (see Zabala et al 2010) their eventual success will not guarantee a recovery of European mink populations because of the deleterious effects of habitat fragmentation.…”

“…In the case of absolute barriers there are no possibilities of exiting the river due to the existence of other impediments. (1) the length of the main river (streams between 4 and 15 m in width), considering only those streams which are represented on the 1:50,000 and 1:25,000 scale maps (http://www1.euskadi.net/cartografia/ see in Zabala et al 2010); (2) the length of the largest stretch of the main river free from barriers; (3) the number of river dams in the main stream which could be considered as real barriers to mink movement (little dams or those with fish scales were not considered); (4) the number of tributaries affected by slight river barriers; (5) the number of tributaries affected by moderate river barriers; (6) the number of tributaries affected by absolute river barriers; (7) the number of tributaries which were free from barriers. We only considered tributaries of at least one km in length and 1.5 m in width, represented on the 1:10,000 scale maps (http://www1.euskadi.net/cartografia/).…”

The compensatory potential of increased immigration following intensive American mink population control is diluted by male-biased dispersal

“…Zabala et al 2010), nevertheless remains dependent on funding packages of fixed duration and is subject to interim lapses in financial support, as well as pressure to deliver more for less resources. Therefore, a management approach with a focus on known hotspot areas, or extrapolating across habitat types, should represent an efficient use of available resources.…”

Misleading interpretation of shifting baseline syndrome in the conservation of European mink

“…Meanwhile, the Spanish distribution area is being overtaken by the American mink, and local extinctions of the European species are being confirmed less than 10 years after invasion (Zabala et al 2010;Zuberogoitia et al 2013;Põdra et al 2014).…”