Browsing by Subject "Wildlife conservation"

Now showing 1 - 3 of 3
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    Active monitoring of long-eared owl (Asio otus) nestlings reveals widespread exposure to anticoagulant rodenticides across different agricultural landscapes
    (Elsevier, 2024-03-25) Spadetto, Livia; Zamora Marín, José Manuel; León Ortega, Mario; Díaz García, Sarah; Tecles, Fernando; Fenoll, José; Cava, Juana; Calvo, José Francisco,; García Fernández, Antonio Juan; Gómez Ramírez, Pilar; Ciencias Sociosanitarias
    The widespread use of anticoagulant rodenticides (ARs) poses a worldwide threat to farmland wildlife. These compounds accumulate in tissues of both target and non-target species, potentially endangering both direct consumers and their predators. However, investigations on ARs in blood of free-ranging predatory birds are rare. Here, the long-eared owl (Asio otus) has been used as a model predator to assess AR exposure in different agricultural landscapes from a Mediterranean semiarid region. A total of 69 owlets from 38 nests were blood-sampled over 2021 and 2022, aiming to detect AR residues and explore factors that determine their exposure, such as land uses. In addition, prothrombin time (PT) test was conducted to assess potential effects of AR contamination. Overall, nearly all the samples (98.6 %) tested positive for at least one compound and multiple ARs were found in most of the individuals (82.6 %). Among the ARs detected, flocoumafen was the most common compound (88.4 % of the samples). AR total concentration (Sigma ARs) in blood ranged from 0.06 to 34.18 ng mL(-1), detecting the highest levels in the most intensively cultivated area. The analysis of owl pellets from 19 breeding territories showed relevant among-site differences in the contribution of rodents and birds into the diet of long-eared owls, supporting its high dietary plasticity and indicating AR presence at multiple trophic levels. Moreover, a positive and significant correlation was found between Sigma ARs and PT (Rho = 0.547, p < 0.001), which demonstrates the direct effect of ARs on free-living nestlings. Our results provide a preliminary overview of AR exposure in a little-studied owl species inhabiting agricultural and rural landscapes. Despite the low detected levels, these findings indicate widespread exposure -often to multiple compounds- from early life stages, which raises concern and draws attention to an ongoing and unresolved contamination issue.
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    Open Access
    Comparing anticoagulant rodenticide exposure in barn owl (Tyto alba) and common kestrel (Falco tinnunculus): A biomonitoring study in an agricultural region of southeastern Spain
    (Elsevier, 2024-09-10) Spadetto, Livia; Zamora-López, Antonio; Manuel Zamora-Marín, José; León-Ortega, Mario; Tórtola-García, Miguel; Tecles-Vicente, Fernando; Fenoll-Serrano, José; Cava-Artero, Juana; Calvo, José Francisco; García Fernández, Antonio Juan; Gómez Ramírez, Pilar; Ciencias Sociosanitarias
    Second-generation anticoagulant rodenticides (SGARs) are commonly used for rodent control, affecting various non-target wildlife species. Here, blood samples from common kestrels ( Falco tinnunculus, , n = 70 chicks) and barn owls ( Tyto alba, n = 54 chicks and 12 adults) from Southeastern Spain were analysed using HPLC-TQ. SGAR prevalence was 68.6% in kestrel chicks, 50% in barn owl chicks and 100% in adult barn owls, with multiple SGARs in both species. Prothrombin time analysis in barn owls revealed a positive correlation with blood Sigma SGARs, suggesting a potential adverse effect on coagulation. Analysis of variables potentially influencing SGAR prevalence indicated that, for kestrels, it was only related to the extent of artificial surface, showing no differences across study sites. In owlets, the highest prevalence occurred in the most urbanized study site, with human population density being a key factor. This study highlights species-specific differences in SGAR exposure, likely influenced by ecological traits. Barn owls probably encounter contaminated prey near anthropized areas, with widespread SGAR use and higher presence of target rodents. Conversely, kestrels, hunting a variety of prey often near human settlements, face consistently elevated exposure from multiple sources. Understanding these variations is crucial for effective conservation and minimizing SGAR impact on non-target wildlife.
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    Ecological values of intermittent rivers for terrestrial vertebrate fauna
    (Elsevier, 2022-02) Sánchez Montoya, María del Mar; Gómez Cerezo, Rosa María; Calvo, Jose Francisco; Bartonička, Tomáš; Thibault, Datry; Paril, Petr; Ecología e Hidrología
    Rivers are generally considered critical habitats for biodiversity; however, this often ignores the fact that many rivers may run dry and support terrestrial as well as aquatic fauna. Here, we investigated the ecological value of intermittent rivers for terrestrial vertebrates by installing camera traps along rivers subject to varying dry periods in two contrasting European climatic zones. We then analysed i) species presence and behaviours (as a proxy of ecological functions) on perennial and intermittent streams; ii) environmental (hydrological and geomorphological) and anthropogenic factors affecting the frequency of occurrence and number of species recorded; and iii) the importance of hydrological factors as regards ecological functioning. In both study areas,we recorded a higher number of species and individuals along intermittent streams than perennial streams, with highest values in intermittent reaches exhibiting shorter dry periods. Both abundance and species richnesswere strongly affected by hydrological factors in both study areas, including not only the occurrence but also the duration of the dry period. Dry channels played a key role as migration corridors and as a source of food, being used more frequently than riparian habitatswhen the river ran dry. Our findings indicate that terrestrial vertebrate fauna benefit fromdry phases in rivers. Intermittent rivers, supporting a high abundance and diversity of fauna, should be considered as target ecosystems for wildlife conservation. Not doing so will jeopardise urgently needed conservation strategies in the face of accelerating global climate change.