Conservation with local people: Medicinal plants as cultural keystone species in the Southern Alps

The concept of “cultural keystone species” (CKS) combines ecological and socioeconomic aspects and has a great potential for improving the overall success of conservation and restoration of ecosystems. In our study, we combined an ecological analysis of traditional medicinal plant species with an explorative analysis of the stakeholder landscape to understand the importance of plants for local communities. We investigate the feasibility of the CKS concept for traditional medicinal plants using the Southern Alps (Northern Italy) as a case study. Based on a comprehensive survey of traditional medicinal plants, we analyzed the habitats where they occur and their significance as CKS candidates. We applied the index of identified cultural influence (ICI). We identified some of the relevant stakeholders and their potential interest in traditional medicinal plants. From a total of 273 native medicinal species, we ranked the 10 most important CKS candidates. These comprised species with different ecology such as the herbs Achillea millefolium agg., Alchemilla xanthochlora, Arnica montana, Hypericum perforatum, Matricaria chamomilla, Peucedanum ostruthium, Urtica dioica, the shrub Juniperus communis, and the tree species Betula pendula. By merging their importance for the local communities with their occurrences in the habitats of South Tyrol, the concept of CKS can stimulate species and habitat conservation, and ecosystem restoration

Back to the future? Conservative grassland management can preserve soil health in the changing landscapes of Uruguay

The “soils of the Anthropocene” are predominately agricultural. To understand them, we analyzed agri- and silvicultural intensification of Uruguayan grasslands (GLs) in a country-wide survey on fertility proxies, pH and trace metals in topsoils originating from different land uses across the whole country. Thus, our results reflect interactions of both the natural diversity of Uruguayan soil formation and the impacts of land use change. We observed a loss of nutrients, trace metals and organic matter from GLs, croplands and timber plantations (TPs). As an example, the cation exchange capacity was 160 % higher in native forests (NFs) compared to GLs and lowest in TPs, reaching only half of the cation exchange capacity (CEC) in GLs. Acidification of topsoils continues as three-fourths of all samples are “extremely acidic” and “very strongly acidic”. Topsoils of riverine forests accumulate more trace metals compared to the other uses. We assume an accumulation in the topsoils of riverine forests, where high levels of nutrients, trace metals and organic carbon (OC) are found. The translocation of nutrients and organic matter across the landscape to the erosion base depends on local land use trajectories. Increasing soil acidification is driving a positive feedback loop, and land use intensification has lead to degradation of local black soils within a few decades. Our data raise questions about the resilience and carrying capacity of Uruguayan soils with regard to currently implemented highly productive management forms, including the use of TPs for carbon sequestration, and supports more conservative forms of extensive management on the GL biome.</p

Does soil pyrogenic carbon determine plant functional traits in Amazon Basin forests?

Amazon forests are fire-sensitive ecosystems and consequently fires affect forest structure and composition. For instance, the legacy of past fire regimes may persist through some species and traits that are found due to past fires. In this study, we tested for relationships between functional traits that are classically presented as the main components of plant ecological strategies and environmental filters related to climate and historical fires among permanent mature forest plots across the range of local and regional environmental gradients that occur in Amazonia. We used percentage surface soil pyrogenic carbon (PyC), a recalcitrant form of carbon that can persist for millennia in soils, as a novel indicator of historical fire in old-growth forests. Five out of the nine functional traits evaluated across all 378 species were correlated with some environmental variables. Although there is more PyC in Amazonian soils than previously reported, the percentage soil PyC indicated no detectable legacy effect of past fires on contemporary functional composition. More species with dry diaspores were found in drier and hotter environments. We also found higher wood density in trees from higher temperature sites. If Amazon forest past burnings were local and without distinguishable attributes of a widespread fire regime, then impacts on biodiversity would have been small and heterogeneous. Alternatively, sufficient time may have passed since the last fire to allow for species replacement. Regardless, as we failed to detect any impact of past fire on present forest functional composition, if our plots are representative then it suggests that mature Amazon forests lack a compositional legacy of past fire