Carrion ecology, i.e. the decomposition and recycling of dead animals, has traditionally been neglected as a key process in ecosystem functioning. Similarly, despite the large threats that inland aquatic ecosystems (hereafter, aquatic ecosystems) face, the scientific literature is still largely biased towards terrestrial ecosystems. However, there has been an increasing number of studies on carrion ecology in aquatic ecosystems in the last two decades, highlighting their key role in nutrient recirculation and disease control. Thus, a global assessment of the ecological role of scavengers and carrion in aquatic ecosystems is timely. Here, we systematically reviewed scientific articles on carrion ecology in aquatic ecosystems to describe current knowledge, identify research gaps, and promote future studies that will deepen our understanding in this field. We found 206 relevant studies, which were highly biased towards North America, especially in lotic ecosystems, covering short time periods, and overlooking seasonality, a crucial factor in scavenging dynamics. Despite the low number of studies on scavenger assemblages, we recorded 55 orders of invertebrates from 179 families, with Diptera and Coleoptera being the most frequent orders. For vertebrates, we recorded 114 species from 40 families, with birds and mammals being the most common. Our results emphasise the significance of scavengers in stabilising food webs and facilitating nutrient cycling within aquatic ecosystems. Studies were strongly biased towards the assessment of the ecosystem effects of carrion, particularly of salmon carcasses in North America. The second most common research topic was the foraging ecology of vertebrates, which was mostly evaluated through sporadic observations of carrion in the diet. Articles assessing scavenger assemblages were scarce, and only a limited number of these studies evaluated carrion consumption patterns, which serve as a proxy for the role of scavengers in the ecosystem. The ecological functions performed by carrion and scavengers in aquatic ecosystems were diverse. The main ecological functions were carrion as food source and the role of scavengers in nutrient cycling, which appeared in 52.4% (N = 108) and 46.1% (N = 95) of publications, respectively. Ecosystem threats associated with carrion ecology were also identified, the most common being water eutrophication and carrion as source of pathogens (2.4%; N = 5 each). Regarding the effects of carrion on ecosystems, we found studies spanning all ecosystem components (N = 85), from soil or the water column to terrestrial vertebrates, with a particular focus on aquatic invertebrates and fish. Most of these articles found positive effects of carrion on ecosystems (e.g. higher species richness, abundance or fitness; 84.7%; N = 72), while a minority found negative effects, changes in community composition, or even no effects. Enhancing our understanding of scavengers and carrion in aquatic ecosystems is crucial to assessing their current and future roles amidst global change, mainly for water–land nutrient transport, due to changes in the amount and speed of nutrient movement, and for disease control and impact mitigation, due to the predicted increase in occurrence and magnitude of mortality events in aquatic ecosystems.

Invasive Alien Species (IAS) alter ecosystems, disrupting ecological processes and driving the loss of ecosystem services. The common carp Cyprinus carpio is a hazardous and widespread IAS, becoming the most abundant species in many aquatic ecosystems. This species transforms ecosystems by accumulating biomass to the detriment of other species, thus altering food webs. However, some terrestrial species, such as vertebrate scavengers, may benefit from dead carps, by incorporating part of the carp biomass into the terrestrial environment. This study describes the terrestrial vertebrate scavenger assemblage that benefits from carp carcasses in a Mediterranean wetland. We also evaluate the seasonal differences in the scavenger assemblage composition and carrion consumption patterns. Eighty carp carcasses (20 per season) were placed in El Hondo Natural Park, a seminatural mesohaline wetland in south‐eastern Spain, and we monitored their consumption using camera traps. We recorded 14 scavenger species (10 birds and four mammals) consuming carp carcasses, including globally threatened species. Vertebrates consumed 73% of the carrion biomass and appeared consuming at 82% of the carcasses. Of these carcasses consumed, 75% were completely consumed and the mean consumption time of carcasses completely consumed by vertebrates was 44.4 h (SD = 42.1 h). We recorded differences in species richness, abundance, and assemblage composition among seasons, but we did not find seasonal differences in consumption patterns throughout the year. Our study recorded a rich and efficient terrestrial vertebrate scavenger assemblage benefitting from carp carcasses. We detected a seasonal replacement on the scavenger species, but a maintenance of the ecological function of carrion removal, as the most efficient carrion consumers were present throughout the year. The results highlight the importance of vertebrate scavengers in wetlands, removing possible infectious focus, and moving nutrients between aquatic and terrestrial environments.

Outdoor recreation has increased in recent decades, with an intensification after the COVID‐19 lockdown. Previous studies have shown that disturbances from this activity may affect species behaviour and fitness, but its effect on ecological processes has been overlooked. Here, we test the impact of outdoor recreation on terrestrial vertebrate scavenger assemblage and scavenging patterns in El Hondo Natural Park, a Mediterranean wetland located in south‐eastern Spain. We placed 185 carcasses monitored with camera traps between February 2020 and May 2021 in two areas: ‘public access area’, where visitors can freely access and carry out outdoor recreation, and ‘restricted area’, where visitors are not allowed. Our results showed that outdoor recreation altered the scavenger assemblage composition, especially affecting large species such as raptors. Non‐native species scavenged almost four times more often on carcasses in public access areas than in the restricted areas, showing that human activities promote the presence of non‐native species. Furthermore, vertebrates completely consumed 68.2% of the carcasses in the restricted area, decreasing to 46.7% in the public access area. In the restricted area, consumption time was shorter (111.8 vs. 157.5 h) and consumed biomass by vertebrate scavengers was larger (73.9 vs. 52.2%) than in public access area, evidencing that outdoor recreation also affects scavenging processes. Our study shows that outdoor recreation profoundly alters not only the scavenger assemblage but also key ecological processes such as carrion removal. This highlights the urgency of regulating tourism and maintaining restricted areas to preserve biodiversity and ecological processes, especially in highly anthropized landscapes.

Capsule: Diet analysis revealed high lead exposure for Greater Spotted Eagles Clanga clanga wintering in southeast Spain. Aims: To describe the diet composition of the endangered Greater Spotted Eagle in a wintering area located in southeast Spain, and determine lead ammunition exposure through analysis of regurgitated pellets and prey remains. Methods: Between 2008 and 2018, a total of 26 pellets, 29 prey remains and 10 direct predation observations were collected in El Hondo Natural Park, Spain. All the pellets and 10 prey remains were analysed with X-ray in order to detect metal from ammunition. Results: Greater Spotted Eagles fed mainly on birds, with 18 different species accounting for 73.1% of prey items and 66.1% of biomass consumed. The most frequent species identified were Common Moorhen Gallinula chloropus (23.1%), rats Rattus spp. (15.4%) and Common Teal Anas crecca (8.9%). Ammunition was detected in 42.3% of regurgitated pellets and in 40.0% of prey remains analysed. Of those containing ammunition, lead shot was found in 63.9% of pellets and 25.0% of prey remains. Conclusion: High lead shot presence in pellets and prey remains of wintering Greater Spotted Eagles in southeast Spain warns of a high risk of lead poisoning. Factors such as feeding behaviour, the large space–time overlap between the raptor presence and the waterbird hunting season and non-compliance with the ban on the use of lead ammunition are likely contributing to high lead exposure.

Domestic dogs (Canis familiaris) significantly threaten endangered vertebrates worldwide. In this study, we report 11 documented cases of dogs chasing, harassing, competing for food resources, biting, and killing six native vertebrate species in the Ecuadorian Andes: Andean condor (Vultur gryphus), mountain tapir (Tapirus pinchaque), little red brocket deer (Mazama rufina), Andean fox (Lycalopex culpaeus), white-tailed deer (Odocoileus virginianus), and Andean tapeti (Sylvilagus andinus). Dog attacks on wildlife can lead to mortality through direct injury and by transmitting diseases, potentially threatening the conservation of globally endangered species such as the Andean condor, mountain tapir, and little red brocket deer. Effective management and conservation of native vertebrates in Andean ecosystems require a comprehensive understanding of the multifaceted impacts of dogs on wildlife populations. These impacts include direct attacks, disease transmission, fear-induced behavioral changes, competition for food resources, and conflicts with local farmers, which may inadvertently lead to wildlife poisoning.

Presentamos datos actualizados sobre la distribución de 20 especies de aves del Ecuador, 16 de estas registradas por primera ocasión dentro de la hoya de Loja, valle inter-Andino del sur del país: Podilymbus podiceps, Phalacrocorax brasilianus, Butorides striata, Bubulcus ibis, Ardea alba, Chondrohierax uncinatus, Rupornis magnirostris, Gallinula galeata, Megascops roboratus, Megaceryle torquata, Aulacorhynchus prasinus, Forpus coelestis, Psittacara erythrogenys, Grallaria guatimalensis, Pitangus sulphuratus, Pachyramphus homochrous, Turdus reevei, Sporophila corvina, Rhynchospiza stolzmanni, y Cardellina canadensis. Únicamente P. brasilianus, B. striata, B. ibis y G. galeata han sido registradas previamente en el área de estudio, sin embargo, para estas especies se presentan nuevas localidades de registro, todas asociadas a pequeñas lagunas existentes alrededor de la ciudad de Loja. Esta información permite incrementar el conocimiento sobre la distribución geográfica y altitudinal de estas aves en el sur de Ecuador.