The use of human mediated translocations has been an increasing component of many species recovery initiatives, including for numerous imperiled Lepidopteran species. Despite the identified need for this ex situ strategy, few such programs are conducted in a scientifically repeatable way, are executed with a structured decision-making process, are well documented throughout, or are documented only in gray literature. The International Union for Conservation of Nature’s Guidelines for Reintroductions and Other Conservation Translocations are an important tool for conservation practitioners to help implement comprehensive translocation planning. These generalized guidelines are intended to be applicable to all taxa. Though there is a growing body of literature and supplementary guidelines for many vertebrate classes, other proposed standards fail to capture the specific biology of many invertebrate groups, like Lepidoptera. Here, we present a targeted list of detailed recommendations that are appropriate for Lepidopteran translocation programs to expand on the broad and tested guidelines developed by the IUCN. We assert that the increased standardization and repeatability among Lepidopteran translocations will improve the conservation outcomes.
With only ~1% of native prairie remaining in North America, populations of many prairie-obligate species, including the imperiled Dakota skipper butterfly, have drastically declined in recent decades. Unfortunately, population recovery is impeded by an insufficient understanding of Dakota skipper biology. Because larvae have never been naturally observed in the wild, even basic life history elements including preferred host plant(s) are not well understood, and potential hosts have been inferred from grasses inhabiting remnant sites rather than direct observations. To improve our understanding of Dakota skipper biology and habitat needs and inform recovery efforts, we conducted a no-choice performance experiment offering larvae 1 of 5 commonly occurring native grasses and 2 pervasive invasive grass species found across their historic range. We monitored larvae during key life history intervals and evaluated host plant quality by measuring larval and pupal mass, time to pupation, and survivorship. Larvae fed on all offered host grasses, but mass, phenology, and survivorship varied among treatments. Larvae reared on prairie dropseed and porcupine grass had the highest survival, the shortest time to adulthood, and the greatest mass, whereas larvae provided smooth brome and Kentucky bluegrass fared poorly for all observed metrics. All other grasses offered during the study were deemed ‘medium’ quality. Our results suggest that although larvae can feed on a variety of potential host plants, these hosts vary in quality. Invasive grasses across prairies in North America may pose an ecological trap to the conservation of Dakota skipper and other prairie-obligate Lepidoptera.
Vector-borne disease prevalence is increasing at a time when surveillance capacity in the United States is decreasing. One way to address this surveillance deficiency is to utilize established infrastructure, such as zoological parks, to investigate animal disease outbreaks and improve our epidemiological understanding of vector-borne pathogens. During fall 2020, an outbreak of epizootic hemorrhagic disease (EHD) at the Minnesota Zoo resulted in morbidity and seroconversion of several collection animals. In response to this outbreak, insect surveillance was conducted, and the collected insects were tested for the presence of epizootic hemorrhagic disease virus (EHDV) by RT-qPCR to better understand the local transmitting vector populations responsible for the outbreak. Six pools of Culicoides biting midges were positive for EHDV, including three pools of Culicoides sonorensis, two pools of Culicoides variipennis, and a pool of degraded C. variipennis complex midges. All three endemic serotypes of EHDV (1, 2, and 6) were detected in both animals and midge pools from the premises. Despite this outbreak, no EHDV cases had been reported in wild animals near the zoo. This highlights the importance and utility of using animal holding facilities, such as zoos, as sentinels to better understand the spatio-temporal dynamics of pathogen transmission.
The field of wildlife conservation is comprised of a variety of players with different contexts and approaches. Zoos and aquariums, historically largely focused on public entertainment, are shifting more towards conservation-minded missions and can play a unique role in wildlife conservation by leveraging their distinct assets. The Minnesota Zoo is an AZA-accredited institution and an agency of the State of Minnesota that has been conducting wildlife conservation for over 40 years. Here, we review our current portfolio of local field projects, including initiatives targeting pollinators, native mussels, turtles, and bison, using several considerations to structure and better understand how our unique context has shaped our work. Our designation as a state agency has impacted our initiatives by necessitating a focus on local efforts and has facilitated many partnerships with other government agencies. Indeed, partnerships have been vital to our success and have shaped our programs significantly since their inception. All of the Zoo’s conservation initiatives are built on a bedrock of sound science, and we continue to contribute to the field through research, utilizing the expertise of department staff. In addition, the various funding streams that support our programs have dramatically shaped our work and have created some siloing of staff within the department. However, grant funding can serve as a buffer against the impacts of economic uncertainty, as evidenced during the COVID-19 pandemic. Lastly, our programs have expanded and our objectives have pivoted over the years in response to changing needs and opportunities; such flexibility—and increased flexibility for our staff—is imperative to the future success of these efforts. The Minnesota Zoo’s narrative is unique and helps us understand how we can continue to most effectively carry out local conservation efforts. As we work to protect habitats and save species from extinction, it is important to utilize the distinct assets that each organization can contribute in order to have the greatest collective impact.
Population viability analysis (PVA) can be a useful decision‐support tool to leverage uncertainty to avoid conservation hesitancy and paralysis. We developed a novel PVA model to help evaluate the effectiveness of a range of ex situ management options for the Critically Endangered Poweshiek skipperling butterfly. The PVA indicated that the last three known United States populations face high likelihoods of extinction in the absence of supportive ex situ management, particularly when population sizes and in situ survival rates are low. Modelling indicated that a headstarting program initiated in 2017 to reinforce these populations was only likely delaying extirpation. Persistence probabilities fell once the program was concluded, regardless of population size or survival rate. An alternative ex situ breeding program provided significant boosts to the persistence of all populations by producing significantly more individuals available for releases than a headstarting program reliant on in situ population sizes could provide. Withholding individuals to establish a large ex situ breeding population did not impose a notable penalty on wild populations and improved persistence. Persistence was boosted further when an ex situ breeding program was combined with headstarting to reinforce populations. Based on these model outcomes, we elected to pivot management strategies from headstarting to reinforcement via an ex situ breeding programme. Effective PVAs are contingent on the incorporation of as much information as possible, acknowledgement of uncertainty, and flexibility. PVAs provide research opportunities and have been under‐utilised in insect conservation. Our model is likely the first to link ex situ management to in situ dynamics for an invertebrate.