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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]ebd.csic.es: 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


https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0242082
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A novel system for ranking and comparing the impacts of introduced species

A novel system for ranking and comparing the impacts of introduced species

Many alien taxa are known to cause socio-economic impacts by affecting the different constituents of human well-being (security; material and immaterial assets; health; social, spiritual and cultural relations; freedom of choice and action). Attempts to quantify socio-economic impacts in monetary terms are unlikely to provide a useful basis for evaluating and comparing impacts of alien taxa because they are notoriously difficult to measure and important aspects of human well-being are excluded or ignored. A novel standardised method for classifying alien taxa in terms of the magnitude of their impacts on human well-being is proposed, based on the capability approach from welfare economics. The core characteristic of this approach is that it uses changes in people's activities as a common metric for evaluating impacts on well-being. Impacts are assigned to one of five levels, from Minimal Concern to Massive, according to semi-quantitative scenarios that describe the severity of the impacts. Taxa are then classified according to the highest level of deleterious impact that they have been recorded to cause on any constituent of human well-being. The scheme also includes categories for taxa that are Not Evaluated, have No Alien Population, or are Data Deficient, and a method for assigning uncertainty to all the classifications. To demonstrate the utility of the system, impacts of amphibians were globally classified. These showed a variety of impacts on human wellbeing, with the cane toad (Rhinella marina) scoring Major impacts. For most species, however, no studies reporting impacts on human well-being were found, i.e. these species were Data Deficient. The classification provides a consistent procedure for translating the broad range of measures and types of impact into ranked levels of socioeconomic impact, assigns alien taxa on the basis of the best available evidence of their documented deleterious impacts, and is applicable across taxa and at a range of spatial scales. The system was designed to align closely with the Environmental Impact Classification for Alien Taxa (EICAT) and the Red List, both of which have been adopted by the International Union of Nature Conservation (IUCN), and could therefore be readily integrated into international practices. Methods in Ecology and Evolution Doi 10.1111/2041-210X.12844


http://onlinelibrary.wiley.com/doi/10.1111/2041-210X.12844/full