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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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Physiological mechanisms of adaptive developmental plasticity in Rana temporaria island populations

Physiological mechanisms of adaptive developmental plasticity in Rana temporaria island populations

Adaptive plasticity is essential for many species to cope with environmental heterogeneity. In particular, developmental plasticity allows organisms with complex life cycles to adaptively adjust the timing of ontogenetic switch points. In this study, the physiological mechanisms underlying divergent degrees of developmental plasticity across Rana temporaria island populations inhabiting different types of pools in northern Sweden is investigated. In a laboratory experiment it was estimated developmental plasticity against pond drying of amphibian larvae from six populations coming from three different island habitats: islands with only permanent pools, islands with only ephemeral pools, and islands with a mixture of both types of pools. It was found that populations from islands with only temporary pools had a higher degree of developmental plasticity than those from the other two types of habitats. Tadpoles from islands with temporary pools showed lower constitutive activities of catalase and glutathione reductase, and also showed overall shorter telomeres. The observed differences are indicative of physiological costs of increased developmental plasticity, suggesting that the potential for plasticity is constrained by its costs. Thus, high levels of responsiveness in the developmental rate of tadpoles have evolved in islands with pools at high but variable risk of desiccation. Moreover, the physiological alterations observed may have important consequences for both short-term odds of survival and long term effects on lifespan. informacion[at]ebd.csic.es: Burraco et al (2017) Physiological mechanisms of adaptive developmental plasticity in Rana temporaria island populations. BMC Evol Biol doi: 10.1186/s12862-017-1004-1 


https://bmcevolbiol.biomedcentral.com/articles/10.1186/s12862-017-1004-1