Optimal allocation of conservation effort among subpopulations of a threatened species: How important is patch quality?

Money is often a limiting factor in conservation, and attempting to conserve endangered species can be costly. Consequently, a framework for optimizing fiscally constrained conservation decisions for a single species is needed. In this paper we find the optimal budget allocation among isolated subpopulations of a threatened species to minimize local extinction probability. We solve the problem using stochastic dynamic programming, derive a useful and simple alternative guideline for allocating funds, and test its performance using forward simulation. The model considers subpopulations that persist in habitat patches of differing quality, which in our model is reflected in different relationships between money invested and extinction risk. We discover that, in most cases, subpopulations that are less efficient to manage should receive more money than those that are more efficient to manage, due to higher investment needed to reduce extinction risk. Our simple investment guideline performs almost as well as the exact optimal strategy. We illustrate our approach with a case study of the management of the Sumatran tiger, Panthera tigris sumatrae, in Kerinci Seblat National Park (KSNP), Indonesia. We find that different budgets should be allocated to the separate tiger subpopulations in KSNP. The subpopulation that is not at risk of extinction does not require any management investment. Based on the combination of risks of extinction and habitat quality, the optimal allocation for these particular tiger subpopulations is an unusual case: subpopulations that occur in higher-quality habitat (more efficient to manage) should receive more funds than the remaining subpopulation that is in lower-quality habitat. Because the yearly budget allocated to the KSNP for tiger conservation is small, to guarantee the persistence of all the subpopulations that are currently under threat we need to prioritize those that are easier to save. When allocating resources among subpopulations of a threatened species, the combined effects of differences in habitat quality, cost of action, and current subpopulation probability of extinction need to be integrated. We provide a useful guideline for allocating resources among isolated subpopulations of any threatened species. © 2010 by the Ecological Society of America.

Extremely Low Microsatellite Diversity but Distinct Population Structure in a Long-Lived Threatened Species, the Australian Lungfish Neoceratodus forsteri (Dipnoi)

The Australian lungfish is a unique living representative of an ancient dipnoan lineage, listed as ‘vulnerable’ to extinction under Australia’s Environment Protection and Biodiversity Conservation Act 1999. Historical accounts indicate this species occurred naturally in two adjacent river systems in Australia, the Burnett and Mary. Current day populations in other rivers are thought to have arisen by translocation from these source populations. Early genetic work detected very little variation and so had limited power to answer questions relevant for management including how genetic variation is partitioned within and among sub-populations. In this study, we use newly developed microsatellite markers to examine samples from the Burnett and Mary Rivers, as well as from two populations thought to be of translocated origin, Brisbane and North Pine. We test whether there is significant genetic structure among and within river drainages; assign putatively translocated populations to potential source populations; and estimate effective population sizes. Eleven polymorphic microsatellite loci genotyped in 218 individuals gave an average within-population heterozygosity of 0.39 which is low relative to other threatened taxa and for freshwater fishes in general. Based on F_ST values (average over loci = 0.11) and STRUCTURE analyses, we identify three distinct populations in the natural range, one in the Burnett and two distinct populations in the Mary. These analyses also support the hypothesis that the Mary River is the likely source of translocated populations in the Brisbane and North Pine rivers, which agrees with historical published records of a translocation event giving rise to these populations. We were unable to obtain bounded estimates of effective population size, as we have too few genotype combinations, although point estimates were low, ranging from 29 - 129. We recommend that, in order to preserve any local adaptation in the three distinct populations that they be managed separately.

Managing threatened species – the ecological toolbox, evolutionary theory and the declining-population paradigm

1. The management of threatened species is an important practical way in which conservationists can intervene in the extinction process and reduce the loss of biodiversity. Understanding the causes of population declines (past, present and future) is pivotal to designing effective practical management. This is the declining-population paradigm identified by Caughley. 2. There are three broad classes of ecological tool used by conservationists to guide management decisions for threatened species: statistical models of habitat use, demographic models and behaviour-based models. Each of these is described here, illustrated with a case study and evaluated critically in terms of its practical application. 3. These tools are fundamentally different. Statistical models of habitat use and demographic models both use descriptions of patterns in abundance and demography, in relation to a range of factors, to inform management decisions. In contrast, behaviourbased models describe the evolutionary processes underlying these patterns, and derive such patterns from the strategies employed by individuals when competing for resources under a specific set of environmental conditions. 4. Statistical models of habitat use and demographic models have been used successfully to make management recommendations for declining populations. To do this, assumptions are made about population growth or vital rates that will apply when environmental conditions are restored, based on either past data collected under favourable environmental conditions or estimates of these parameters when the agent of decline is removed. As a result, they can only be used to make reliable quantitative predictions about future environments when a comparable environment has been experienced by the population of interest in the past. 5. Many future changes in the environment driven by management will not have been experienced by a population in the past. Under these circumstances, vital rates and their relationship with population density will change in the future in a way that is not predictable from past patterns. Reliable quantitative predictions about population-level responses then need to be based on an explicit consideration of the evolutionary processes operating at the individual level. 6. Synthesis and applications. It is argued that evolutionary theory underpins Caughley’s declining-population paradigm, and that it needs to become much more widely used within mainstream conservation biology. This will help conservationists examine critically the reliability of the tools they have traditionally used to aid management decision-making. It will also give them access to alternative tools, particularly when predictions are required for changes in the environment that have not been experienced by a population in the past.

Managing threatened species: the ecological toolbox, evolutionary theory and declining-population paradigm

1. The management of threatened species is an important practical way in which conservationists can intervene in the extinction process and reduce the loss of biodiversity. Understanding the causes of population declines (past, present and future) is pivotal to designing effective practical management. This is the declining-population paradigm identified by Caughley. 2. There are three broad classes of ecological tool used by conservationists to guide management decisions for threatened species: statistical models of habitat use, demographic models and behaviour-based models. Each of these is described here, illustrated with a case study and evaluated critically in terms of its practical application. 3. These tools are fundamentally different. Statistical models of habitat use and demographic models both use descriptions of patterns in abundance and demography, in relation to a range of factors, to inform management decisions. In contrast, behaviour-based models describe the evolutionary processes underlying these patterns, and derive such patterns from the strategies employed by individuals when competing for resources under a specific set of environmental conditions. 4. Statistical models of habitat use and demographic models have been used successfully to make management recommendations for declining populations. To do this, assumptions are made about population growth or vital rates that will apply when environmental conditions are restored, based on either past data collected under favourable environmental conditions or estimates of these parameters when the agent of decline is removed. As a result, they can only be used to make reliable quantitative predictions about future environments when a comparable environment has been experienced by the population of interest in the past. 5. Many future changes in the environment driven by management will not have been experienced by a population in the past. Under these circumstances, vital rates and their relationship with population density will change in the future in a way that is not predictable from past patterns. Reliable quantitative predictions about population-level responses then need to be based on an explicit consideration of the evolutionary processes operating at the individual level. 6. Synthesis and applications. It is argued that evolutionary theory underpins Caughley's declining-population paradigm, and that it needs to become much more widely used within mainstream conservation biology. This will help conservationists examine critically the reliability of the tools they have traditionally used to aid management decision-making. It will also give them access to alternative tools, particularly when predictions are required for changes in the environment that have not been experienced by a population in the past.

Assessing programs for monitoring threatened species – a tale of three honeyeaters (Meliphagidae)

We critically evaluated population-monitoring programs for three endangered species of Australian honeyeater: the helmeted honeyeater, Lichenostomus melanops cassidix, the black-eared miner, Manorina melanotis, and the regent honeyeater, Xanthomyza phrygia (Meliphagidae). Our results challenge the common assumption that meaningful monitoring is possible in all species within the five-year lifetime of recovery plans. We found that the precision achievable from monitoring programs not only depends on the monitoring technique applied but also on the species' biology. Relevant life-history attributes include a species' pattern of movement, its home-range size and its distribution. How well understood and predictable these attributes are will also influence monitoring precision. Our results highlight the large degree of variability in precision among monitoring programs and the value of applying power analysis before continuing longer-term studies. They also suggest that managers and funding agencies should be mindful that more easily monitored species should not receive preferential treatment over species that prove more difficult to monitor.

Stakeholder perceptions of threatened species and their management on urban beaches

We surveyed 579 recreationists regarding management of the threatened, beach-dwelling Hooded Plover Thinornis rubricollis. We postulated that: (1) lower awareness of the species and higher ‘inconvenience’ of management would engender less favourable perceptions of conservation and management; and (2) that frequency of beach use and dog ownership may mediate perceptions and levels of awareness and inconvenience. Overall, inconvenience was low while awareness and support for plover conservation were high. Education and awareness strategies were considered less effective than regulations; exclusion and regulations were considered less desirable than on-ground protective measures. Awareness, frequency of beach use and dog walking did not influence the perceived effectiveness of different managements. More frequent beach users had greater awareness of the species and their plight but reported greater inconvenience associated with management. Respondents with high awareness rated the severity of human-related threats higher; low awareness was associated with more inconvenience associated with on-ground protection, and exclusion and regulations. Dog walkers reported more inconvenience associated with exclusions and regulations than non-dog walkers. Dog walkers who used the beach infrequently rated threats significantly higher than frequent beach users. Conservation and education strategies could usefully be tailored to beach users’ level of use and pet ownership.

Persistence of a threatened species in a modified alpine resort environment: the broad-toothed rat

Habitat change due to resort development threatens rare and endemic fauna of alpine and subalpine regions. There is an urgent need to understand species persistence in such areas. The broad-toothed rat (Mastacomys fuscus) is a rare, specialist species found in alpine and subalpine regions of Australia. We conducted fecal pellet surveys in an alpine resort to determine the species' distribution and habitat requirements. Eight individuals were radiotracked to investigate movement patterns and habitat use. Fecal pellets were found in areas of dense vegetation cover up to 1 m above ground. Home ranges were small (1,488-6,106 m²) and encompassed managed indigenous vegetation on or beside ski runs. Five individuals regularly crossed a narrow (3-5 m) cleared track. Two adult males dispersed (including traversing a wide grassy ski run) up to 1 km. The ability to cross modified areas and move throughout the landscape is proposed as a key factor facilitating the persistence of M. fuscus in the resort. Enhancing the capacity of species to move between habitat patches should be incorporated into alpine resort management plans. Such management will become increasingly important as anthropogenic disturbance increases in alpine regions.

Do social values influence levels of conservation effort in threatened species? The case of two Australian chats

This research aims to understand why one of two almost identical subspecies of the Australian yellow chat Ephthianura crocea has received significantly higher levels of local and institutional support than the other despite both having the same conservation status and taxonomic distinctiveness, factors commonly thought to influence conservation effort. Using a qualitative multiple case study approach we explored how a range of social factors, including stakeholder attitudes and institutional, policy and operational aspects, might have affected conservation efforts for the two taxa. Our results suggest that the conservation trajectories of these two subspecies have diverged since their identification as threatened species in 2000 because of differences in the social landscapes within which they persist. For one subspecies local advocacy was kindled initially by the small number of local endemic bird species but developed into a strong emotional engagement, resulting in increased local awareness, government funding, and effectiveness of conservation action. The other subspecies has had to compete for attention with approximately 200 other threatened taxa occurring in its region. No individual advocate has accorded this subspecies a high priority for action, and none of those responsible for its conservation have seen it or acknowledged an emotional attachment to it. Our findings confirm that initiation of conservation effort is strongly tied to the social values of individuals with power to take action, regardless of legislation.

A new and threatened species of Scinax (Anura: Hylidae) from Queimada Grande Island, southeastern Brazil

We describe a new species of hylid frog, Scinax peixotoi, from Queimada Grande Island, southeastern Brazil. The new species belongs to the Scinax perpusillus species group, in which all known forms inhabit bromeliads, and is diagnosed by the following set of characters: moderate-size (males 18.8-20.7 mm SVL, females 22.4-25.1 mm SVL); canthus rostralis distinct; dorsal skin slightly rugose; and a distinct advertisement call with relatively low dominant frequency. The new species is known from a single population on Queimada Grande, an island of 43 ha, approximately 33 km distant from the coast of São Paulo State, where it inhabits scattered patches of bromeliads. The highly specialized and patchy habitat of S. peixotoi, associated with its small range size, make this species highly susceptible to stochastic or anthropogenic habitat disturbances, which could lead it to extinction. Copyright © 2007 Magnolia Press.

Severe population decline of marsh deer, Blastocerus dichotomus (Cetartiodactyla: Cervidae), a threatened species, caused by flooding related to a hydroelectric power plant

Balancing power production and environmental conservation can be problematic. The objective of this study was to investigate the abundance of marsh deer in the Paraná River Basin, above the Sergio Motta (Porto Primavera) Dam, before and after the impact of the dam closure. A fixed-wing, flat window aircraft was used to survey study transects. Observations were recorded based on the distance sampling line transect method, assuming that the detection probability decreases with increased distance. The abundance of marsh deer in the survey region prior to flooding was estimated to be 974 individuals (CV = 0.23). The overall abundance dropped from 974 to 444 (CV = 0.26) individuals after flooding, an overall reduction of 54%. This reduction can be attributed to the direct impact of the flooding process, but it was likely exacerbated by indirect effects, such as increased disease, hunting, and reduction in food availability. Prior to flooding, the marsh deer was distributed widely throughout the dam's catchment area; however, the marsh deer habitat was almost completely destroyed by the flooding process. This situation highlights the need to implement management strategies that ensure the survival of the remaining fragmented population.

Redescription of Hyphessobrycon flammeus Myers, 1924 (Ostariophysi: Characidae), a threatened species from Brazil

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

The Economics of Threatened Species Conservation: A Review and Analysis

Stabilizing human population size and reducing human-caused impacts on the environment are keys to conserving threatened species (TS). Earth's human population is ~ 7 billion and increasing by ~ 76 million per year. This equates to a human birth-death ratio of 2.35 annually. The 2007 Red List prepared by the International Union for Conservation of Nature and Natural Resources (IUCN) categorized 16,306 species of vertebrates, invertebrates, plants, and other organisms (e.g., lichens, algae) as TS. This is ~ 1 percent of the 1,589,161 species described by IUCN or ~ 0.0033 percent of the believed 5,000,000 total species. Of the IUCN’s described species, vertebrates comprised relatively the most TS listings within respective taxonomic categories (5,742 of 59,811), while invertebrates (2,108 of 1,203,175), plants (8,447 of 297,326), and other species (9 of 28,849) accounted for minor class percentages. Conservation economics comprises microeconomic and macroeconomic principles involving interactions among ecological, environmental, and natural resource economics. A sustainable-growth (steady-state) economy has been posited as instrumental to preserving biological diversity and slowing extinctions in the wild, but few nations endorse this approach. Expanding growth principles characterize most nations' economic policies. To date, statutory fine, captive breeding cost, contingent valuation analysis, hedonic pricing, and travel cost methods are used to value TS in economic research and models. Improved valuation methods of TS are needed for benefit-cost analysis (BCA) of conservation plans. This Chapter provides a review and analysis of: (1) the IUCN status of species, (2) economic principles inherent to sustainable versus growth economies, and (3) methodological issues which hinder effective BCAs of TS conservation.

Evaluation of reproductive sucess and conservation strategies for Senecio coincyi (Asteraceae), a narrow and threatened species

Senecio coincyi is a threatened endemic plant of central western Spain, with a very narrow extent of occurrence. The reproductive success and germination behaviour of this species were studied. The area of occupancy, habitat types and size of 13 known subpopulations of S. coincyi were evaluated. The number of individuals that form all these subpopulations was counted. In addition, the number of flowers and cypselas per fruit head and the number of fruit heads per individual plant were recorded in a subset of subpopulations. Germination tests were carried out to evaluate the effect of temperature and light regimes on, and possible intraspecific variation in, cypsela germination. Cypselas reached very high germination percentages (90?100%) from 15?C to 30?C. However, the germination decreased (19%) at 10?C. The light conditions assayed (16-h light photoperiod and complete darkness) did not significantly affect cypsela germination. In general, there was no intraspecific variability in germination patterns of S. coincyi cypselas. Livestock is the most important factor that can be a threat for this species. S. coincyi showed high reproductive success and, therefore, its conservation problems are not due to agents related to its reproduction, but rather to other factors such as alteration of its habitat caused by the presence of livestock.