Browsing by Autor "Patrick F. Chapman"

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Global population size and conservation priority areas for the endangered Titicaca grebe
(Wiley, 2024) D. A. Villar; Paola Velásquez‐Noriega; Edwin R. Gutiérrez Tito; Anahi Cosky Paca‐Condori; Edmundo G. Moreno Terrazas; Ronald Hinojosa Cárdenas; Alfredo Balcón Cuno; Carmen Villanueva; Patrick F. Chapman; Jhazel Quispe
Abstract The Titicaca grebe ( Rollandia microptera ) is a poorly studied endangered species, only found in the Lake Titicaca watershed of Peru and Bolivia. Population surveys undertaken in the early twenty‐first century suggested that the species had declined in number by >70%. We conducted a population survey of the grebe between March and August 2022 in Peru and Bolivia, using both maximum entropy and Bayesian occupancy models to estimate factors affecting habitat suitability for the grebe. We conducted surveys between March and August 2022 in Peru and Bolivia. Contrary to the International Union for Conservation of Nature (IUCN) population estimates of <1,000 individuals, there are likely tens of thousands of individual grebes. The population estimation was sensitive to the type of model used. Distance from shore and fishing intensity were the most significant factors influencing grebe populations. The Reserva Nacional del Titicaca, the only protected area in the lake, covers some of the most suitable Titicaca grebe habitat across its entire range. The population of the Titicaca grebe is significantly higher than previous estimates, but we do not recommend a change to its conservation status because of the lack of conservation efforts for this species, and the long‐term risks associated with global warming and fisheries bycatch.
Problems with combining modelling and social science approaches to understand artisanal fisheries bycatch
(Wiley, 2024) D. A. Villar; Edwin R. Gutiérrez Tito; Paola Velásquez‐Noriega; Anahi Cosky Paca‐Condori; Edmundo G. Moreno Terrazas; Alfredo Balcón Cuno; Ronald Hinojosa Cárdenas; Carmen Villanueva; Patrick F. Chapman; Luca Chiaverini
Abstract Aim Artisanal fisheries account for 40% of the world's fisheries catch, yet its environmental impacts remain poorly understood. This is especially the case in developing countries. In this study, we sought to integrate Local Fisher's Knowledge with distribution modelling to estimate the annual bycatch of Titicaca Grebe ( Rollandia microptera ), an endangered endemic bird from Lake Titicaca whose main anthropogenic threat is bycatch. Location Lake Titicaca, Peru and Bolivia. Methods We conducted transect and point counts of fishing nets in March–September 2022 and conducted interviews with fishers across the Lake Titicaca region. Using bathymetry, distance from shore, distance from a settlement, distance from the protected area, presence/absence of aquaculture, distance from aquaculture, and wetland cover, we constructed a distribution model of fisheries using maximum entropy modelling. We conducted interviews with fishers asking about the frequency of grebe bycatch and conducted short‐term monitoring at various sites while conducting transect points for dead grebes. Results We estimate 3270 km 2 of the surface area of Lake Titicaca is used for fishing, which amounts to 39.40% of the lake's surface area. The area under the curve (AUC) of the distribution model was 0.89 and the True Skill Statistic was 0.67, which suggests maximum entropy modelling can model fisheries occurrence. The results of our interviews suggested a biologically implausible large number of grebes caught as bycatch annually. The cultural context of the interviews, including potential influences of non‐response and social‐desirability bias, being with fishers who often view the Titicaca Grebe as a nuisance species, might have caused over‐reporting of bycatch and hence led to these implausible figures. Main Conclusions It is possible to map fisheries using distribution models as one might with species. However, obtaining accurate measures of fisheries bycatch through interviews is more difficult, due to cultural factors which affect the accuracy in fisher's responses. While we hope that this method provides a low‐cost alternative to monitoring, it is not a suitable replacement for it.