Toward Consensus-Based Actions that Balance Invasive Plant Management and Conservation of At-Risk Fauna

Abstract

Limiting the spread of invasive plants has become a high priority among natural resource managers. Yet in some regions, invasive plants are providing important habitat components to native animals that are at risk of local or regional extirpation. In these situations, removing invasive plants may decrease short-term survival of the at-risk taxa. At the same time, there may be a reluctance to expand invaded habitats to benefit at-risk species because such actions may increase the distribution of invasive plants. Such a dilemma can result in "management paralysis," where no action is taken either to reduce invasive plants or to expand habitats for at-risk species. A pragmatic solution to this dilemma may be to develop an approach that considers site-specific circumstances. We constructed a "discussion tree" as a means of initiating conversations among various stakeholders involved with managing habitats in the northeastern USA to benefit several at-risk taxa, including New England cottontails (Sylvilagus transitionalis). Major components of this approach include recognition that expanding some invaded habitats may be essential to prevent extirpation of at-risk species, and the effective control of invasive plants is dependent on knowledge of the status of invasives on managed lands and within the surrounding landscape. By acknowledging that management of invasive plants is a complex issue without a single solution, we may be successful in limiting their spread while still addressing critical habitat needs.

Developing a habitat suitability index to guide restoration of New England cottontail habitats

“…We acknowledge that generically, invasive shrubs cannot be easily categorized as either detrimental or beneficial to NECs. Available information suggests that the cover value of certain invasive shrubs can be comparable to, or even greater than, some native shrubs (Litvaitis et al 2013); and relative value of invasive and native shrubs as winter forage are largely unknown. Additional considerations when addressing management protocols toward invasive shrubs would be their prevalence in the surrounding landscape (Litvaitis et al 2013) and the importance of the site to other thicketaffiliated taxa.…”

“…Available information suggests that the cover value of certain invasive shrubs can be comparable to, or even greater than, some native shrubs (Litvaitis et al 2013); and relative value of invasive and native shrubs as winter forage are largely unknown. Additional considerations when addressing management protocols toward invasive shrubs would be their prevalence in the surrounding landscape (Litvaitis et al 2013) and the importance of the site to other thicketaffiliated taxa. For example, some invasive shrubs support fewer insects that are an important food source of nesting songbirds and their developing offspring (Fickenscher et al 2014).…”

Separating Proactive Conservation from Species Listing Decisions

“…This interaction has the capacity to further alter composition of shrublands in favor of invasive shrubs and slow natural succession. While the possibility of invasive shrubs to increase or decrease habitat quality for New England cottontails was recognized prior to the listing decision (Litvaitis et al, 2013 ), there had been no research on the impact of exotic invasive plants on habitat quality for New England cottontails. Anecdotal observations indicated that where these shrubs were abundant, their removal might result in destruction of critical resources for New England cottontails and patch level extinctions (Litvaitis et al, 2013 ).…”

“…While the possibility of invasive shrubs to increase or decrease habitat quality for New England cottontails was recognized prior to the listing decision (Litvaitis et al, 2013 ), there had been no research on the impact of exotic invasive plants on habitat quality for New England cottontails. Anecdotal observations indicated that where these shrubs were abundant, their removal might result in destruction of critical resources for New England cottontails and patch level extinctions (Litvaitis et al, 2013 ). Since then, formal study has supported the hypothesis that the architecture of dense invasive shrubs, such as multiflora rose ( Rosa multiflora ) and Japanese barberry ( Berberis thunbergii ), can provide valuable cover resources to New England cottontail and promote survival under certain high-canopy conditions (Cheeseman et al, 2019a ; Cheeseman et al, 2018 ).…”

Determinants of home-range size of imperiled New England cottontails (Sylvilagus transitionalis) and introduced eastern cottontails (Sylvilagus floridanus)

“…Invasive shrub species are also particularly pervasive in successional shrublands (Litvaitis et al 2013). For New England cottontails these shrubs may provide a beneficial cover resource (Litvaitis et al 2013;Warren et al 2016;Cheeseman et al 2018), but may also reduce the abundance and diversity of other plant species (Silander and Klepeis 1999;Yurkonis et al 2005), which could have detrimental impacts on the quality or availability of forage resources.…”