Patch connectivity and genetic diversity conservation in the federally endangered and narrowly endemic plant species Astragalus albens (Fabaceae)

To evaluate the sufficiency of US federal critical habitat designations and a proposed conservation plan in promoting the long-term persistence of the endangered plant Astragalus albens, patterns of genetic diversity and landscape connectivity were examined. A. albens harbors substantial genetic variation and shows no evidence of historic bottlenecks, suggesting little risk of extinction due to genetic homogeneity (A = 2.40; P = 0.50) or inbreeding (f = −0.08) within occurrences. Low genetic differentiation among occurrences (θ_p = 0.01) indicates relatively high gene flow or little genetic drift. The 91 patches of A. albens were connected into a single network at a distance of 2100 m; 94% of patches were <1000 m from at least one other patch. Managing ecological conditions that maintain large population sizes and connectivity among populations throughout the species’ ecological and geographic ranges will most likely conserve existing diversity. Both reserve networks partially accomplish these goals by including most extant occurrences and >89% of the aerial extent of the species, including the largest populations, and capturing all detected alleles. However, both conservation networks fail to conserve occurrences from one portion of the species’ range, possibly speeding loss of unique local adaptations. In addition, connectivity of the whole network is reduced with the 65 patches designated as critical habitat being connected at a distance of 6200 m and the proposed reserve sites being connected at a distance of 9500 m. Although total network connectivity would be reduced, connectivity at scales most relevant to gene flow (e.g., <1000 m) remains sufficiently in tact to provide a relatively promising outlook for species persistence.     

An attempt to recover the Po'ouli by translocation and an appraisal of recovery strategy for bird species of extreme rarity

The Po'ouli (Melamprosops phaeosoma), a Hawaiian honeycreeper endemic to Maui, has a population of only three known individuals; no breeding pair currently exists, and their home ranges are too far apart for breeding to occur. Without timely intervention this monotypic genus will likely go extinct. Conservationists have faced a dilemma: facilitate breeding amongst the known individuals, manage their ecosystem to benefit uncounted Po'ouli, or a combination of both? Po'ouli biology is poorly known - but their remote home ranges are closely monitored. A State and Federal Environmental Assessment in 1999 recommended that one Po'ouli be translocated into the home range of another in an attempt to facilitate breeding. This first manipulative recovery action was achieved in April 2002, and provided valuable new information for future captive management efforts, but upon release, radio telemetry confirmed that the translocated bird returned to its own home range after one day. We describe the recent progress that has been made to recover the Po'ouli, and critically evaluate the Po'ouli case study and the lessons learned from it that can help expedite recovery of other birds of extreme rarity.     

Paying for wolves in Solapur, India and Wisconsin, USA: Comparing compensation rules and practice to understand the goals and politics of wolf conservation

With growing pressure for conservation to pay its way, the merits of compensation for wildlife damage must be understood in diverse socio-ecological settings. Here we compare compensation programs in Wisconsin, USA and Solapur, India, where wolves (Canis lupus) survive in landscapes dominated by agriculture and pasture. At both sites, rural citizens were especially negative toward wolves, even though other wild species caused more damage. Wisconsin and Solapur differ in payment rules and funding sources, which reflect distinct conservation and social goals. In Wisconsin, as wolves recolonized the state, some periodically preyed on livestock and hunting dogs. Ranchers and some hunters were more likely to oppose wolves than were other citizens. The Wisconsin compensation program aimed to restore an iconic species by using voluntary contributions from wolf advocates to pay affected individuals more for wolf losses than for other species. By contrast, wolves had been continuously present in Solapur, and damages were distributed amongst the general populace. Government-supported compensation payments were on offer to anyone suffering losses, yet claims registered were low. There were no significant differences in attitudes of any particular segment of the population, but those losing high value livestock applied for compensation. Residents at both sites did not report (Wisconsin) or expect (Solapur) a change in attitude towards wolves as a result of compensation, yet they support the existence of such programs. To assess the merits of any compensation program, one must disentangle the multiple goals of compensation, such as reducing wolf killing or more fairly sharing the costs of conserving large carnivores.     

Survey of New Zealand Department of Conservation staff involved in the management and recovery of threatened species

In terms of managing biodiversity, a third of the land area of New Zealand is included in a conservation estate of national parks, reserves and sanctuaries. Administration of this large natural heritage asset is by 13 separate Department of Conservation (DOC) conservancies. A survey was conducted, across all conservancies, of DOC staff directly involved with the management and recovery of threatened New Zealand species. The aim of the survey was to gain an insight into how DOC staff regard the management tools available to them for the recovery of threatened species. The survey also assessed the perceived relevance of the threatened species recovery plans (TSRPs) currently in use by these staff. The results of the survey show that in general, the DOC staff consider that a lack of adequate funding, poor communication between conservancies and staff shortages have resulted in failure to achieve comprehensive management and recovery of threatened species. There was an expectation for TSRPs to comprehensively guide management and recovery actions but most staff concluded that TSRPs failed to meet this objective. It was identified that TSRPs need to be kept up-to-date and preferably in an electronic format accessible to all DOC staff throughout New Zealand. There was strong support for the establishment of a national approach for the recovery of threatened species. Concern was expressed that current resourcing only allowed recovery of a very small number of New Zealand’s threatened species with staff calling for secure funding for the duration of threatened species recovery programmes.     

Recovery expenditures for birds listed under the US Endangered Species Act: The disparity between mainland and Hawaiian taxa

Since the arrival of humans more than half of the Hawaiian archipelago’s known endemic bird taxa have been lost. Of the taxa that remain, 31 are federally listed under the US Endangered Species Act and 17 have populations of less than 1000 individuals. Previous studies have documented a geographic disparity in recovery expenditures on listed species, but none have specifically focused on Hawaiian birds. To draw attention to this disparity with the aim to improve Hawaiian bird conservation, I summarized recovery expenditures on listed birds from 1996 to 2004 comparing mainland and Hawaiian taxa in the context of their degree of endangerment. Federal and state spending on the 95 listed bird taxa over this nine year period totaled $752,779,924. Hawaiian birds comprise a third of the listed bird taxa (n = 31), yet dedicated recovery expenditures was only $30,592,692 or 4.1% of the total spent on all listed birds. Despite similar priority ranks assigned by the US Fish and Wildlife Service, listed mainland birds received over 15 times the funding of Hawaiian birds. In general, the threats to island taxa are unlike those of mainland taxa (e.g., non-native predators), management actions are expensive, and in many cases they must be conducted in perpetuity. Because of the status of many Hawaiian birds and the threats facing them, current recovery expenditures are inadequate to prevent additional extinctions.     

Population viability, ecological processes and biodiversity: Valuing sites for reserve selection

No-take reserves constitute one tool to improve conservation of marine ecosystems, yet criteria for their placement, size, and arrangement remain uncertain. Representation of biodiversity is necessary in reserve planning, but will ultimately fail for conservation unless factors affecting species’ persistence are also incorporated. This study presents an empirical example of the divergent relationships among multiple metrics used to quantify a site’s conservation value, including those that address representation (habitat type, species richness, species diversity), and others that address ecological processes and viability (density and reproductive capacity of a keystone species, in this case, the black chiton, Katharina tunicata). We characterized 10 rocky intertidal sites across two habitats in Barkley Sound, British Columbia, Canada, according to these site metrics. High-richness and high-production sites for K. tunicata were present in both habitat types, but high richness and high-production sites did not overlap. Across sites, species richness ranged from 29 to 46, and adult K. tunicata varied from 6 to 22 individuals m⁻². Adult density was negatively correlated with species richness, a pattern that likely occurs due to post-recruitment growth and survival because no correlation was evident with non-reproductive juveniles. Sites with high adult density also contributed disproportionately greater potential reproductive output (PRO), defined by total gonad mass. PRO varied by a factor of five across sites and was also negatively correlated with species richness. Compromise or relative weighting would be necessary to select valuable sites for conservation because of inherent contradictions among some reserve selection criteria. We suspect that this inconsistency among site metrics will occur more generally in other ecosystems and emphasize the importance of population viability of strongly interacting species.     

Dispersal of breeding, adult male Phocarctos hookeri: Implications for disease transmission, population management and species recovery

Dispersal impacts on a range of population parameters making it a key piece of information in species conservation. Despite its importance, dispersal is poorly characterized for many species: pinnipeds are no exception. Understanding dispersal patterns of the New Zealand sea lion Phocarctos hookeri is crucial in the conservation management of the species as its recovery to a non-threatened status hinges on range recolonisation. In this study, we examined the movements of breeding adult male New Zealand sea lions within and following the breeding season of the 2002/03 austral summer using a novel multi colony approach. Based on resightings of 202 individually identifiable adult males, we found (1) a previously unappreciated, high level of dispersal by adult territorial males between breeding colonies during the pupping period and (2) that breeding males disperse to the extremes of the species’ range at the end of female oestrous. Our findings are contrary to the current paradigm of otariid breeding behaviour, which is believed to consist of prolonged, uninterrupted male territoriality based on intense male-male competition and sustained fasting. Adult male dispersal between colonies and across the species range has important implications for adult males as vectors of disease in three recent epizootics, species management and species recovery via recolonisation as males are apparently remaining part of a localized, vulnerable breeding population.     

Chemical composition and diversity influence non-additive effects of litter mixtures on soil carbon and nitrogen cycling: Implications for plant species loss

Diverse plant litter mixtures frequently decompose differently than expected compared to the average of the component species decomposing alone, and it remains unclear why decomposition may respond non-additively to diversity. Here, we hypothesized that litter chemical composition and chemical diversity would be important determinants of the strength and direction (synergistic versus antagonistic) of non-additive soil carbon (C) and nitrogen (N) cycling responses to litter mixtures. To test this, we performed a soil incubation experiment using litter mixtures comprised of up to four plant species, and we measured three components of decomposition: respiration, net N mineralization, and microbial biomass N accumulation. We used nine chemical traits to calculate the chemical composition and diversity of the litter mixtures. First, we found that respiration responded as the average of the individual species in the mixture (i.e. additively), rather than non-additively as initially predicted. Second, litter mixtures stimulated significantly more net N immobilization than expected in 64% of cases, and non-additive responses were highly dependent on mixture chemical composition, and were influenced to a lesser degree by chemical diversity. Specifically, concentrations of tannins and certain low molecular weight phenolics in the mixtures were positively correlated with greater N immobilization than expected. Non-additive N mineralization responses were poorly correlated with traditional measures of litter chemistry like N concentration, C:N, lignin:N, and phenolic:N. Our results also show that non-additive N mineralization responses were affected by loss of some species significantly more than others, and the effects of species loss could depend on 1) whether a species contains compounds with strong effects on non-additive responses; and 2) whether those compounds are also found in other species. Finally, litter mixtures stimulated more microbial biomass N than expected in 45% of cases, but non-additive responses were only weakly dependent on the litter chemistry variables that we measured.