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Understanding the processes leading to fossilization

Modern death assemblages provide insights about the early stages of fossilization and useful ecological information about the species inhabiting the ecosystem. The results of taphonomic monitoring of modern vertebrate carcasses and bones from Doñana National Park, a Mediterranean coastal ecosystem in Andalusia, Spain, are presented. Ten different habitats were surveyed. Half of them occur in active depositional environments (marshland, lake margin, river margin, beach and dunes). Most of the skeletal remains belong to land mammals larger than 5 kg in body weight (mainly wild and feral ungulates). Overall, the Doñana bone assemblage shows good preservation with little damage to the bones, partly as a consequence of the low predator pressure on large vertebrates. Assemblages from active depositional habitats differ significantly from other habitats in terms of the higher incidence of breakage and chewing marks on bones in the latter, which result from scavenging, mainly by wild boar and red fox. The lake-margin and river-margin death assemblages have high concentrations of well preserved bones that are undergoing burial and offer the greatest potential to produce fossil assemblages. The spatial distribution of species in the Doñana death assemblage generally reflects the preferred habitats of the species in life. Meadows seem to be a preferred winter habitat for male deer, given the high number of shed antlers recorded there. This study is further proof that taphonomy can provide powerful insights to better understand the ecology of modern species and to infer past and future scenarios for the fossil record. informacion[at] Domingo et al (2020) Taphonomic information from the modern vertebrate death assemblage of Doñana National Park, Spain. PLOS ONE 15(11): e0242082. DOI 10.1371/journal.pone.0242082
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Humans and scavenging raptors facilitate Argentine ant invasion in Doñana National Park

Humans and scavenging raptors facilitate Argentine ant invasion in Doñana National Park

Biotic resistance by native communities could have a role in the spread of invasive species. Native communities with higher species richness should be less susceptible to invasion by exotic species than those with fewer component species, interspecific interactions acting as biotic barriers by creating a highly competitive environment. This seems to be the case in the invasion of the Argentine ant, Linepithema humile, but only when the environment is unfavorable for the survival of the invader. The progress of Argentine ant invasion through favorable and unfavorable habitats of Doñana National Park was studied across three temporal snapshots covering three decades (1992, 2000, 2016). Biotic resistance of the native community was assessed using species richness, as well as dominance and community structure. The role of abiotic factors (quality of surrounding habitat and spatial variables) and of potential vectors of Argentine ant dispersal across unfavorable areas was also explored. No evidence of biotic resistance was found. On the contrary, invasion proceeded from trees with higher ant species richness, probably because those trees are larger and provide more resources and better protection from aridity. Furthermore, evidence was found that the invasion of new trees across a matrix of unfavorable habitat could be influenced not only by humans, but also by scavenging avian predators, which could act as vectors of ant dispersal through transport of carrion also exploited by the ants. Such leapfrog expansion through mobile predators could represent an overlooked mechanism that would enrich our understanding of invasion dynamics and provide potential opportunities for management of invasive species. informacion[at] Castro-Cobo et al (2019) Humans and scavenging raptors facilitate Argentine ant invasion in Doñana National Park: no counter-effect of biotic resistance. Biol Invasions 21:2221–2232. Doi 10.1007/s10530-019-01971-5