Marie Montenegro Violeta, Mateo-Tomás Patricia, Schneider Jessica, Dent Daisy H, Crowther Tom, Bello Carolina
Department of Environmental Systems Science ETH Zürich Switzerland.
Biodiversity Research Institute (University of Oviedo - CSIC - Principado de Asturias) Mieres Spain.
Ecol Evol. 2025 Jan 8;15(1):e70485. doi: 10.1002/ece3.70485. eCollection 2025 Jan.
Scavenging is a widespread feeding strategy involving a diversity of taxa from different trophic levels, from apex predators to obligate scavengers. Scavenger species play a crucial role in ecosystem functioning by removing carcasses, recycling nutrients and preventing disease spread. Understanding the trophic roles of scavenger species can help identify specialized species with unique roles and species that may be more vulnerable to ecological changes. To identify species with specialized roles, we studied three scavenger networks (one in north temperate Spain and two in central-south Mediterranean Spain) that comprised 25 scavenger species (65% birds and 35% mammals), consuming carcasses of four wild ungulate species. We characterized the trophic role of a species by combining four species-level network metrics (normalized degree, specialization, closeness, and betweenness centrality) into a single centrality metric, quantifying how scavenger species interact with carcass species within their ecological network. Higher centrality indicates the species feeds on a greater variety of carcasses and may contribute more to carrion consumption than species with lower centrality, which have more peripheral and specialized roles. The griffon vulture () and the azure-winged magpie () had the highest centrality. In contrast, the red kite () in the northern site had the lowest centrality, and the Egyptian vulture () was among the most peripheral species for all three networks. In general, scavengers with large home ranges and nocturnal or crepuscular activity patterns tended to have more central roles, whereas species that forage silently tended to have more peripheral roles. Changes in species' centrality between sites and the high centrality of species with large home ranges suggest that management strategies in one location can have implications that extend beyond, highlighting the need to implement coordinated transboundary protection efforts to ensure the resilience and functionality of scavenger networks and derived ecosystem services.
食腐是一种广泛存在的觅食策略，涉及来自不同营养级别的多种生物分类群，从顶级食肉动物到专性食腐动物。食腐物种通过清除尸体、循环营养物质和防止疾病传播，在生态系统功能中发挥着至关重要的作用。了解食腐物种的营养作用有助于识别具有独特作用的特殊物种以及可能更容易受到生态变化影响的物种。为了识别具有特殊作用的物种，我们研究了三个食腐网络（一个位于西班牙北部温带地区，两个位于西班牙中南部地中海地区），这些网络包含25种食腐物种（65%为鸟类，35%为哺乳动物），它们以四种野生有蹄类动物的尸体为食。我们通过将四个物种水平的网络指标（标准化度、专业化程度、紧密性和中介中心性）组合成一个单一的中心性指标，来描述一个物种的营养作用，量化食腐物种在其生态网络中与尸体物种的相互作用方式。中心性越高表明该物种以更多种类的尸体为食，并且与中心性较低、作用更边缘化和更具专业性的物种相比，可能对腐肉消耗的贡献更大。兀鹫（）和蓝翅喜鹊（）具有最高的中心性。相比之下，北部地区的红鸢（）中心性最低，而埃及秃鹫（）在所有三个网络中都属于最边缘化的物种之一。一般来说，活动范围大且具有夜间或晨昏活动模式的食腐动物往往具有更核心的作用，而觅食时安静的物种往往具有更边缘化的作用。不同地点物种中心性的变化以及活动范围大的物种的高中心性表明，一个地区的管理策略可能会产生超出该地区的影响，这凸显了实施协调一致的跨界保护措施以确保食腐网络及其衍生的生态系统服务的恢复力和功能的必要性。
