Hunter Reporting of Catch per Unit Effort as a Monitoring Tool in a Bushmeat-Harvesting System

The Institute of Zoology, Zoological Society of London, Regent's Park, London NW14RY, United Kingdom.
Conservation Biology (Impact Factor: 4.17). 04/2010; 24(2):489-99. DOI: 10.1111/j.1523-1739.2010.01470.x
Source: PubMed


Growing threats to biodiversity in the tropics mean there is an increasing need for effective monitoring that balances scientific rigor with practical feasibility. Alternatives to professional techniques are emerging that are based on the involvement of local people. Such locally based monitoring methods may be more sustainable over time, allow greater spatial coverage and quicker management decisions, lead to increased compliance, and help encourage attitude shifts toward more environmentally sustainable practices. Nevertheless, few studies have yet compared the findings or cost-effectiveness of locally based methods with professional techniques or investigated the power of locally based methods to detect trends. We gathered data on bushmeat-hunting catch and effort using a professional technique (accompanying hunters on hunting trips) and two locally based methods in which data were collected by hunters (hunting camp diaries and weekly hunter interviews) in a 15-month study in Equatorial Guinea. Catch and effort results from locally based methods were strongly correlated with those of the professional technique and the spatial locations of hunting trips reported in the locally based methods accurately reflected those recorded with the professional technique. We used power simulations of catch and effort data to show that locally based methods can reliably detect meaningful levels of change (20% change with 80% power at significance level [α]= 0.05) in multispecies catch per unit effort. Locally based methods were the most cost-effective for monitoring. Hunter interviews collected catch and effort data on 240% more hunts per person hour and 94% more hunts per unit cost, spent on monitoring, than the professional technique. Our results suggest that locally based monitoring can offer an accurate, cost-effective, and sufficiently powerful method to monitor the status of natural resources. To establish such a system in Equatorial Guinea, the current lack of national and local capacity for monitoring and management must be addressed.
Resumen: Las crecientes amenazas a la biodiversidad en los trópicos significan que hay una necesidad imperiosa de monitoreo efectivo que balancee el rigor científico con la factibilidad práctica. Están emergiendo alternativas a las técnicas profesionales que se basan en la participación de los habitantes locales. Tales métodos de monitoreo basados localmente pueden ser más sustentables con el tiempo, permiten mayor cobertura espacial y tomar decisiones de manejo más rápidamente, llevan a mayor cumplimiento y ayudan a estimular cambios hacia prácticas más sustentables ambientalmente. Sin embargo, pocos estudios han comparado los resultados o la rentabilidad de los métodos basados localmente con los de técnicas profesionales o investigado el poder los métodos basados localmente para detectar tendencias. Reunimos datos sobre el esfuerzo y la captura de la cacería de carne silvestre mediante una técnica profesional (acompañamiento de cazadores en viajes de cacería) y mediante dos métodos basados localmente en los que la información fue obtenida por cazadores (diarios de caza y entrevistas semanales a cazadores) en un estudio de 15 meses en Guinea Ecuatorial. Los resultados de esfuerzo y captura de los métodos basados localmente se correlacionaron fuertemente con los de la técnica profesional y los sitios espaciales de los viajes de cacería reportados en los métodos basados localmente reflejaron con precisión los registrados con la técnica profesional. Utilizamos simulaciones del poder de datos de esfuerzo y captura para demostrar que los métodos basados localmente pueden detectar niveles de cambio confiables y significativos (cambio de 20% con 80% de poder en un nivel de significancia [α]= 0.05) en la captura por unidad de especies. Los métodos basados localmente fueron los más rentables para el monitoreo. Las entrevistas a cazadores recolectaron datos de esfuerzo y captura de 240% más cacerías por persona/hora y 94% más cacerías por unidad de costo que la técnica profesional. Nuestros resultados sugieren que el monitoreo basado localmente puede ofrecer un método preciso, rentable y suficientemente poderosos para monitorear el estatus de los recursos naturales. Para establecimiento de tal sistema en Guinea Ecuatorial se debe atender la escasez de capacidad nacional y local para el monitoreo y manejo.

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    • "Hunter reports can provide a proxy for changes in prey abundance (Rist et al., 2010), and indicators of ecological depletion over time in a hunting system including a decrease in mean biomass of species caught (Albrechtsen et al., 2007; Gill et al., 2012; Kümpel et al., 2010), hunters change hunting effort and hunting techniques (Brinkman et al., 2009; Kümpel et al., 2010). In the present study, we used hunting recall data to assess musk deer depletion over time in northwest Yunan, China. "
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    ABSTRACT: Musk deer (Moschus spp.) have been over-exploited leading to steep population declines. The demand for musk for its use in medicine and perfumery industries poses the biggest threat to musk deer. The present study aimed to assess the depletion level of musk deer over time in northwest Yunnan by using hunter reports and dung transect data. Hunters were asked to recall musk gland catch-effort changes between the early 1990s and over two years (January 2009 to December 2010). Surveys using dung transect methodology were conducted on musk deer population in poaching and non-poaching sites. The results obtained revealed that the hunting frequency is constant in the two periods. Annual musk gland catch per hunter significantly declined from 7.4 (SD = 1.8) in the early 1990s to 0.7 (SD = 0.9) over the 2009-2010 period. A significantly higher proportion of hunters used snares over the 2009-2010 period (74%) than in the early 1990s (18%). The majority of the informants (70%) reported that the average distance from the village at which hunters operated has increased over the later two year period. The mean dung encounter rate values in the non-poaching site were about six times higher than that in poaching sites. Hunter responses were consistent with dung transect data that suggest musk deer population is seriously compromised throughout its range in northwest Yunnan. The present study has shown that catch-effort data from hunter reports can provide pertinent information about the current hunting practices and problems of prey depletion and for design of conservation interventions for hunted species.
    Journal for Nature Conservation 10/2014; 22(5). DOI:10.1016/j.jnc.2014.05.004 · 1.65 Impact Factor
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    • "The use of geographic information systems and GPS in natural resource management is growing. Although citizen science programs have begun taking advantage of these technologies (Crall et al. 2010), we are unaware of other studies evaluating the accuracy of GPS use by volunteers (but see Jones et al. 2008; Rist et al. 2010). Most of our participants had little or no experience with GPS use prior to our training but were generally able to use this tool successfully. "
    Dataset: Crall2011
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    • "Barnes' and Wilkie's hypotheses have been upheld for large species [15,17,20,50,51,133]. However, the majority of studies on hunting have focused on hunters, using only proxies for impacts on prey species [88,153]. Data for wildlife population responses to hunting are only available for large species for which robust census methods are available [154,155]. "
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    ABSTRACT: Humans have hunted wildlife in Central Africa for millennia. Today, however, many species are being rapidly extirpated and sanctuaries for wildlife are dwindling. Almost all Central Africa’s forests are now accessible to hunters. Drastic declines of large mammals have been caused in the past 20 years by the commercial trade formeat or ivory.We reviewa growing body of empirical data which shows that trophic webs are significantly disrupted in the region, with knock-on effects for other ecological functions, including seed dispersal and forest regeneration. Plausible scenarios for land-use change indicate that increasing extraction pressure on Central African forests is likely to usher in new worker populations and to intensify the hunting impacts and trophic cascade disruption already in progress, unless serious efforts aremade for hunting regulation. The profound ecological changes initiated by hunting will not mitigate and may even exacerbate the predicted effects of climate change for the region. We hypothesize that, in the near future, the trophic changes brought about by hunting will have a larger and more rapid impact on Central African rainforest structure and function than the direct impacts of climate change on the vegetation. Immediate hunting regulation is vital for the survival of the Central African rainforest ecosystem.
    Philosophical Transactions of The Royal Society B Biological Sciences 07/2013; 368. DOI:10.1098/rstb.2012.0303 · 7.06 Impact Factor
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