Optimal Marking of Threatened Species to Balance Benefits of Information with Impacts of Marking

Abstract: Marking animals so that they are uniquely identifiable provides information that may assist conservation efforts. Nevertheless, some methods used to mark animals can be harmful. We used mathematical methods to assess the trade‐off between the impact of marking threatened species and the value of the information gained. We considered the case where 2 management strategies, each aiming to improve a species' survival rate, are implemented in an experimental phase. The results of the experiment were applied in a postexperimental management phase. We expressed the expected number of survivors in both phases mathematically, accounting for any mortality caused by the experiment, and determined the proportion of animals to mark to maximize this number. The optimal number of animals to mark increased with the number of individuals available for the experiment and with the number of individuals to be managed in the future. The optimal solution was to mark only 25% of the animals when there were 1000 individuals available for the experiment, the results were used to manage 2000 individuals, and marking caused mortality of 1%. Fewer animals were marked when there were fewer animals in either phase or when marking caused higher mortality. In the case of the Helmeted Honeyeater (Lichenostomus melanops cassidix), the optimal proportion to mark was <1 if the mortality rate was >0.15%–1%, with the threshold depending on the number of animals in the experimental and postexperimental phases. The trade‐off between gaining more information about a species and possibly harming individuals of that species by marking them is difficult to assess subjectively. We show how to determine objectively the optimal proportion of animals to mark to enhance the management of threatened species.     

Optimal Allocation of Conservation Resources to Species That May be Extinct

Abstract: Statements of extinction will always be uncertain because of imperfect detection of species in the wild. Two errors can be made when declaring a species extinct. Extinction can be declared prematurely, with a resulting loss of protection and management intervention. Alternatively, limited conservation resources can be wasted attempting to protect a species that no longer exists. Rather than setting an arbitrary level of certainty at which to declare extinction, we argue that the decision must trade off the expected costs of both errors. Optimal decisions depend on the cost of continued intervention, the probability the species is extant, and the estimated value of management (the benefit of management times the value of the species). We illustrated our approach with three examples: the Dodo (Raphus cucullatus), the Ivory‐billed Woodpecker (U.S. subspecies Campephilus principalis principalis), and the mountain pygmy‐possum (Burramys parvus). The dodo was extremely unlikely to be extant, so managing and monitoring for it today would not be cost‐effective unless the value of management was extremely high. The probability the Ivory‐billed woodpecker is extant depended on whether recent controversial sightings were accepted. Without the recent controversial sightings, it was optimal to declare extinction of the species in 1965 at the latest. Accepting the recent controversial sightings, it was optimal to continue monitoring and managing until 2032 at the latest. The mountain pygmy‐possum is currently extant, with a rapidly declining sighting rate. It was optimal to conduct as many as 66 surveys without sighting before declaring the species extinct. The probability of persistence remained high even after many surveys without sighting because it was difficult to determine whether the species was extinct or undetected. If the value of management is high enough, continued intervention can be cost‐effective even if the species is likely to be extinct.     

Social‐Psychological Principles of Community‐Based Conservation and Conservancy Motivation: Attaining Goals within an Autonomy‐Supportive Environment

Abstract: Community‐based natural resource conservation programs in developing nations face many implementation challenges underpinned by social‐psychological mechanisms. One challenge is garnering local support in an economically and socially sustainable fashion despite economic hardship and historical alienation from local resources. Unfortunately, conservationists' limited understanding of the social‐psychological mechanisms underlying participatory conservation impedes the search for appropriate solutions. We address this issue by revealing key underlying social‐psychological mechanisms of participatory conservation. Different administrative designs create social atmospheres that differentially affect endorsement of conservation goals. Certain forms of endorsement may be less effective motivators and less economically and socially sustainable than others. From a literature review we found that conservation initiatives endorsed primarily for nonautonomous instrumental reasons, such as to avoid economic fines or to secure economic rewards, are less motivating than those endorsed for autonomous reasons, such as for the opportunity for personal expression and growth. We suggest that successful participatory programs promote autonomous endorsement of conservation through an administrative framework of autonomy support—free and open democratic participation in management, substantive recognition and inclusion of local stakeholder identity, and respectful, noncoercive social interaction. This framework of the autonomy‐supportive environment (self‐determination theory) has important implications for future research into program design and incentive‐based conservation and identifies a testable social‐psychological theory of conservancy motivation.     

Decline in Relative Abundance of Bottlenose Dolphins Exposed to Long-Term Disturbance

Abstract:  Studies evaluating effects of human activity on wildlife typically emphasize short-term behavioral responses from which it is difficult to infer biological significance or formulate plans to mitigate harmful impacts. Based on decades of detailed behavioral records, we evaluated long-term impacts of vessel activity on bottlenose dolphins ( Tursiops sp.) in Shark Bay, Australia. We compared dolphin abundance within adjacent 36-km² tourism and control sites, over three consecutive 4.5-year periods wherein research activity was relatively constant but tourism levels increased from zero, to one, to two dolphin-watching operators. A nonlinear logistic model demonstrated that there was no difference in dolphin abundance between periods with no tourism and periods in which one operator offered tours. As the number of tour operators increased to two, there was a significant average decline in dolphin abundance (14.9%; 95% CI =−20.8 to −8.23), approximating a decline of one per seven individuals. Concurrently, within the control site, the average increase in dolphin abundance was not significant (8.5%; 95% CI =−4.0 to +16.7). Given the substantially greater presence and proximity of tour vessels to dolphins relative to research vessels, tour-vessel activity contributed more to declining dolphin numbers within the tourism site than research vessels. Although this trend may not jeopardize the large, genetically diverse dolphin population of Shark Bay, the decline is unlikely to be sustainable for local dolphin tourism. A similar decline would be devastating for small, closed, resident, or endangered cetacean populations. The substantial effect of tour vessels on dolphin abundance in a region of low-level tourism calls into question the presumption that dolphin-watching tourism is benign.     

The Use of Ecologically Based Screening Criteria in a Community-sponsored Open Space Preservation Programme

The Meridian Township Land Preservation Programme is the first community-sponsored, open space and natural areas preservation programme in Michigan using ecological principles in the ranking of properties for acquisition. The programme was established through a collaborative, multi-stakeholder effort that resulted in a model ordinance, operating procedures, guidelines for landowners to nominate their properties for consideration, and a set of criteria for property selection. The screening criteria include ecological value, natural or functional value, parcel size, surrounding land use, environmental quality, and aesthetic value. The criteria were developed to reflect principles established by landscape ecology and land conservation objectives to maintain a maximum degree of biodiversity and to develop, manage and maintain ecological infrastructure through management of protected areas. The programme is entirely funded through a local millage, which will raise nearly $10 million over 10 years. The target for acquisition of open space is approximately 10% of the currently undeveloped parcels in the township.