15 research outputs found

    The ecology and conservation of the pink pigeon Columba Mayeri in Mauritius.

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    The pink pigeon Columba mayeri was a critically endangered endemic bird from Mauritius= in the Indian Ocean. The species reached its lowest point of between 10 and 20 birds in 1975 and the wild population continued to decline to 9 or 10 birds in 1990. The causes of decline included habitat destruction, seasonal food shortages and predation by introduced mammals. Between 1987 and 1997, 256 captive-reared birds were released on Mauritius at three sites. Free-living birds were intensively managed and between 1988 and 1998, 429 young fledged in the wild. The population numbered 297 birds at the end of 1998. Factors limiting survival and reproductive success were identified and an assessment of the re-introduction programme made. Mean survival of j'Qveniles (up to one year old) was 68% and adults 83% per year. Median age at egg-laying for females was 10.9 months and fertility 58.6%. Mean annual nest success was 18.4% and productivity 1.2 young per female from 1992. Productivity for males and females peaked in year one and there was large individual variation, 9% of females produced 43% of young. Survival, nest success and productivity varied between sites, were affected by inbreeding and were poorer for released birds than wild-fledged birds. Causes of nesting failure included predation, infertility and disease. Unhatched eggs accounted for 56% of failed nests in a predator-free environment. Disease affected survival of fledged birds and squabs. On lIe aux Aigrettes trichomoniasis affected 49% of squabs. About 10% of all birds suffered from avian pox and 36% of all birds were infected with Leucocytozoon marchouxi. As a result of the programme, the pink pigeon has been down-listed to endangered. With management, survival and productivity are sufficient to contribute to population growth. This programme was considered a good example of the interface between captive-breeding and the recovery of a wild population

    Working paper analysing the economic implications of the proposed 30% target for areal protection in the draft post-2020 Global Biodiversity Framewor

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    58 pages, 5 figures, 3 tables- The World Economic Forum now ranks biodiversity loss as a top-five risk to the global economy, and the draft post-2020 Global Biodiversity Framework proposes an expansion of conservation areas to 30% of the earth’s surface by 2030 (hereafter the “30% target”), using protected areas (PAs) and other effective area-based conservation measures (OECMs). - Two immediate concerns are how much a 30% target might cost and whether it will cause economic losses to the agriculture, forestry and fisheries sectors. - Conservation areas also generate economic benefits (e.g. revenue from nature tourism and ecosystem services), making PAs/Nature an economic sector in their own right. - If some economic sectors benefit but others experience a loss, high-level policy makers need to know the net impact on the wider economy, as well as on individual sectors. [...]A. Waldron, K. Nakamura, J. Sze, T. Vilela, A. Escobedo, P. Negret Torres, R. Button, K. Swinnerton, A. Toledo, P. Madgwick, N. Mukherjee were supported by National Geographic and the Resources Legacy Fund. V. Christensen was supported by NSERC Discovery Grant RGPIN-2019-04901. M. Coll and J. Steenbeek were supported by EU Horizon 2020 research and innovation programme under grant agreement No 817578 (TRIATLAS). D. Leclere was supported by TradeHub UKRI CGRF project. R. Heneghan was supported by Spanish Ministry of Science, Innovation and Universities, Acciones de Programacion Conjunta Internacional (PCIN-2017-115). M. di Marco was supported by MIUR Rita Levi Montalcini programme. A. Fernandez-Llamazares was supported by Academy of Finland (grant nr. 311176). S. Fujimori and T. Hawegawa were supported by The Environment Research and Technology Development Fund (2-2002) of the Environmental Restoration and Conservation Agency of Japan and the Sumitomo Foundation. V. Heikinheimo was supported by Kone Foundation, Social Media for Conservation project. K. Scherrer was supported by the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme under grant agreement No 682602. U. Rashid Sumaila acknowledges the OceanCanada Partnership, which funded by the Social Sciences and Humanities Research Council of Canada (SSHRC). T. Toivonen was supported by Osk. Huttunen Foundation & Clare Hall college, Cambridge. W. Wu was supported by The Environment Research and Technology Development Fund (2-2002) of the Environmental Restoration and Conservation Agency of Japan. Z. Yuchen was supported by a Ministry of Education of Singapore Research Scholarship Block (RSB) Research FellowshipPeer reviewe

    Ground-based rodent control in a remote Hawaiian rainforest on Maui.

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    Effective control of introduced mammalian predators is essential to the recovery of native bird species in Hawai‘i. Between August 1996 and December 2004, introduced rodents were controlled within three home ranges of the Po‘ouli Melamprosops phaeosoma, a critically endangered Hawaiian honeycreeper. Rats were controlled using a combination of ground-based rodenticide (0.005% diphacinone) application and snap traps. Beginning in August 2001, we monitored the effectiveness of these rodent control efforts. Relative abundances of Black Rats Rattus rattus and Polynesian Rats R. exulans were measured in each of five snap-trapping grids seven times over a 35-month period. Rat populations decreased inside of the rodent control areas, but control effectiveness differed between rat species. During the first year of monitoring, target control levels for R. rattus were consistently achieved in only one of the rodent control areas. Control techniques were refined in areas failing to meet targets. Subsequently, we achieved target control levels for R. rattus more consistently in all three rodent control areas. However, relative abundances of R. exulans did not differ between rodent control and reference areas, indicating that our rodent control techniques were insufficient to reduce population levels of this species. These findings signify a need for further improvement of rodent control methods in Hawai‘i, especially for Polynesian Rats, and demonstrate the critical importance of periodic monitoring of the response of rodent populations to management. In the future, managers may need to design rodent control operations targeting R. rattus and R. exulans independently to achieve best results

    Sudden appearance and population outbreak of \u3ci\u3eEunica monima\u3c/i\u3e (Lepidoptera: Nymphalidae) on Desecheo Island, Puerto Rico

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    We documented the appearance and elevated abundance of the uncommon dingy purplewing butterfly, Eunica monima (Stoll) (Lepidoptera: Nymphalidae), and pronounced herbivory on its host plant Bursera simaruba (L.) Sarg. (Burseraceae) shortly after island-wide rat (Rattus rattus [L.]; Muridae) removal from Desecheo Island, Puerto Rico. We confirmed the species as E. monima by using both molecular and morphological analyses of larvae and adults. This is a first-time record of E. monima for the island of Desecheo, one of relatively few documented appearances in Puerto Rico during the last 100 yr, and an uncommon documentation of an outbreak of this species in the Caribbean. Although experimental manipulation would be needed to identify the cause of the E. monima population outbreak, we discuss possible cause-and-effect scenarios. Documentamos la aparición y elevada abundancia de la mariposa poco común Dingy Purplewing, Eunica monima (Stoll) (Lepidoptera: Nymphalidae), y la pronunciada herbivoría en su planta hospedera Bursera simaruba (L.) Sarg. (Burseraceae), poco después de una erradicación de ratas (Rattus rattus [L.]; Muridae) en la isla de Desecheo, Puerto Rico. Confirmamos la especie como E. monima mediante análisis tanto moleculares como morfológicos de las orugas y adultos. Este es el primer registro de E. monima para la isla de Desecheo, una de las relativamente pocas apariciones documentadas en Puerto Rico durante los últimos 100 años y también se documentó un brote poco común para esta especie en el Caribe. Aunque la manipulación experimental sería necesaria para identificar la causa del brote de E. monima, discutimos los posibles escenarios de causa y efecto

    Spatial genetic architecture of the critically-endangered Maui Parrotbill (Pseudonestor xanthophrys): management considerations for reintroduction strategies

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    Conservation translocations are an important tool to circumvent extinctions on oceanic islands. A thorough understanding of all components of a species’ biology, including genetic diversity and structure, can maximize their likelihood of success. The Maui Parrotbill (Pseudonestor xanthophrys) is an endangered Hawaiian honeycreeper endemic to the island of Maui. With a population of approximately 500 individuals restricted to 50 km2 of habitat, this species is at high risk of extinction. Using nuclear and mitochondrial DNA, this study quantified the levels of genetic diversity and structure in wild and captive parrotbill populations, and compared these genetic patterns to those observed within levels of contemporary and historical nuclear diversity derived from 100-year old museum samples. Substantial differences in the effective population sizes estimated between contemporary and historical parrotbill populations highlight the impact that introduced disease had on this species just before the turn of the century. Contemporary parrotbill diversity was low (global F st = 0.056), and there has been a 96 % reduction in genetic effective population size between contemporary and historical samples. This should not eliminate a conservation translocation (or reintroduction) as a viable recovery option. Measures of population differentiation (pairwise F st and R st ) between different sections of the current population on either side of the Koolau Gap suggest that current genetic structure may be the result of this topographic barrier to gene flow. These data can enable the design of a conservation translocation strategy that is tailored to the patterns of genetic structure across the species’ range

    Decision-analysis to guide recovery of the Po’ouli, a critically endangered Hawaiian honeycreeper

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    We used a probabilistic decision tree to help select among alternative recovery strategies for the Po‘ouli, a critically endangered forest bird endemic to the Hawaiian island of Maui. The Po‘ouli is one of the rarest birds in the world, with only three individuals known, and no breeding pairs. The most urgent conservation need for the species is to create a breeding pair and obtain eggs for captive propagation. Seven recovery strategies had been proposed, and there was disagreement among conservation workers about which strategy to pursue. In addition to lengthy discussions, a decision tree was introduced to provide an objective way of quantifying the chance of success under each alternative. All available information was used to attempt evaluation of each node in the decision tree. The overall chance of obtaining eggs was calculated by multiplying estimates at each node under each alternative. All options produced low estimates of potential success, but two options, removal of all birds to captivity and placement of the birds in a field aviary in an accessible location, produced similar estimates of success. The US Fish and Wildlife Service and the Hawaii Division of Forestry and Wildlife eventually agreed that removal to captivity was the preferred alternative because it could be implemented quickly, which was important considering the advanced age of the birds, and would make it easier to provide veterinary care and ensure their safety from predators, severe weather, and vandals. Decision trees and other structured models should not be relied on exclusively, but they can provide an objective method of helping to make difficult conservation decisions and provide a record of complex thought processes used in reaching a determination. The case of the Po‘ouli may serve as a template for navigation towards a decision to recover other species of extreme rarity

    Ground-based rodent control in a remote Hawaiian rainforest on Maui

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    Effective control of introduced mammalian predators is essential to the recovery of native bird species in Hawai'i. Between August 1996 and December 2004, introduced rodents were controlled within three home ranges of the Po'ouli Melamprosops phaeosoma, a critically endangered Hawaiian honeycreeper. Rats were controlled using a combination of ground-based rodenticide (0.005% diphacinone) application and snap traps. Beginning in August 2001, we monitored the effectiveness of these rodent control efforts. Relative abundances of Black Rats Rattus rattus and Polynesian Rats R. exulans were measured in each of five snap-trapping grids seven times over a 35-month period. Rat populations decreased inside of the rodent control areas, but control effectiveness differed between rat species. During the first year of monitoring, target control levels for R. rattus were consistently achieved in only one of the rodent control areas. Control techniques were refined in areas failing to meet targets. Subsequently, we achieved target control levels for R. rattus more consistently in all three rodent control areas. However, relative abundances of R. exulans did not differ between rodent control and reference areas, indicating that our rodent control techniques were insufficient to reduce population levels of this species. These findings signify a need for further improvement of rodent control methods in Hawai'i, especially for Polynesian Rats, and demonstrate the critical importance of periodic monitoring of the response of rodent populations to management. In the future, managers may need to design rodent control operations targeting R. rattus and R. exulans independently to achieve best results

    Determining productivity of Maui Parrotbills, an endangered Hawaiian honeycreeper

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    Maui Parrotbills (Pseudonestor xanthophrys), critically endangered Hawaiian honeycreepers endemic to the island of Maui, are restricted to a single population of ?500 individuals located in remote, mountainous terrain. From January to June 2006–2011, we located nests and fledglings in the Hanawi Natural Area Reserve (NAR) in east Maui, Hawaii, to document nest success and annual reproductive success. Nest success is a commonly used measure of productivity and is a central component of many demographic studies. Annual reproductive success is less frequently documented because greater effort is required to monitor the reproductive success of breeding pairs through time. However, for species whose nests are difficult to locate or access, such as Maui Parrotbills, the presence or absence of fledged young may provide a more accurate measure of breeding success than monitoring nests. During our study, we located and determined the outcome of 30 nests to document nest success, and monitored 106 territories for the presence or absence of fledglings to calculate annual reproductive success. Nest success probability was 19% (N= 30) and seasonal nest success was 46%. During our monitoring efforts, 49 of 106 breeding pairs produced a single fledged young. Because parrotbills typically have single egg clutches and only re-nest after nests fail, the presence or absence of a fledgling is an indication of a pair's overall reproductive success for a breeding season. Based on the number of fledglings per pair, our estimate of annual reproductive success was 46%, confirming our initial productivity estimate from nests. Thus, our results indicate that the two methods, determining annual reproductive success by monitoring fledglings and calculating nest success, provide similar estimates of annual productivity for Maui Parrotbills. Based on our estimates, the parrotbill population appears to be demographically stable. However, our productivity estimate was based only on the population at Hanawi, an area representing just 3% of the total range of parrotbills. Thus, our results may not accurately reflect the status of parrotbills over their entire range
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