Evidence for self-similar bedload transport on Andean alluvial fans, Iglesia basin, south Central Argentina

Self‐similar downstream grain‐size fining trends in fluvial deposits are being increasingly used to simplify equilibrium sediment transport dynamics in numerical models. Their ability to collapse time‐averaged behavior of a depositional system into a simple mass balance framework makes them ideal for exploring the sensitivity of sediment routing systems to their climatic and tectonic boundary conditions. This is important if we want to better understand the sensitivity of landscapes to environmental change over timescales >102 years. However, the extent to which self‐similarity is detectable in the deposits of natural rivers is not fully constrained. In transport‐limited rivers, stored sediment can be remobilized or “recycled” and this behavior has been highlighted as a mechanism by which externally forced grain‐size fining trends are distorted. Here we evaluate evidence of self‐similarity in surface gravel‐size distributions on three geomorphically diverse alluvial fans in the Iglesia basin, south Central Argentine Andes. We find that size distributions are self‐similar, deviating from that condition only when significant variability occurs in the coarse tails of the distributions. Our analysis indicates a strong correlation between the degree of sediment recycling and the proportion of coarse clasts present on the bed surface. However, by fitting a relative mobility transfer function, we demonstrate that size‐selectivity alone can explain the bulk size distributions observed. This strengthens the application of self‐similar grain size fining models to solving problems of mass balance in a range of geomorphic settings, with an aim for reconstructing environmental boundary conditions from stratigraphy

A formal classification of the Lygeum spartum vegetation of the Mediterranean Region

Aims We examined local and regional contribution on the grasslands dominated by Lygeum spartum from Southern Europe and North Africa to produce a formalised classification of this vegetation and to identify main factors driving its plant species composition. Location Mediterranean Basin and Iberian Peninsula. Methods We used a dataset of 728 relevés, which were resampled to reduce unbalanced sampling effort, resulting in a dataset of 568 relevés and 846 taxa. We classified the plots by TWINSPAN, interpreted the resulting pools, and used them to develop formal definitions of phytosociological alliances characterised by L. spartum vegetation. The definitions were included in an expert system to assist automatic vegetation classification. We related the alliances to climatic factors and described their biogeographical features and ecological preferences. The floristic relationships between these alliances were analysed and visualised using distance‐based redundancy analysis. Results We defined eleven alliances of L. spartum vegetation, including the newly described Launaeo laniferae‐Lygeion sparti from SW Morocco and the Noaeo mucronatae‐Lygeion sparti from the Algerian highlands and NE Morocco. Biogeographical, climatic, and edaphic factors were revealed as putatively driving the differentiation between the alliances. The vegetation of clayey slopes and inland salt basins displayed higher variability in comparison with those of coastal salt marshes. Main conclusions The most comprehensive formal classification, accompanied by an expert system, of the L. spartum vegetation was formulated. The expert system, containing the formal definitions of the phytosociological alliances, will assist in identification of syntaxonomic position of new datasets

A multi-metric approach to investigate the effects of weather conditions on the demographic of a terrestrial mammal, the European badger (Meles meles)

Models capturing the full effects of weather conditions on animal populations are scarce. Here we decompose yearly temperature and rainfall into mean trends, yearly amplitude of change and residual variation, using daily records. We establish from multi-model inference procedures, based on 1125 life histories (from 1987 to 2008), that European badger (Meles meles) annual mortality and recruitment rates respond to changes in mean trends and to variability in proximate weather components. Variation in mean rainfall was by far the most influential predictor in our analysis. Juvenile survival and recruitment rates were highest at intermediate levels of mean rainfall, whereas low adult survival rates were associated with only the driest, and not the wettest, years. Both juvenile and adult survival rates also exhibited a range of tolerance for residual standard deviation around daily predicted temperature values, beyond which survival rates declined. Life-history parameters, annual routines and adaptive behavioural responses, which define the badgers’ climatic niche, thus appear to be predicated upon a bounded range of climatic conditions, which support optimal survival and recruitment dynamics. That variability in weather conditions is influential, in combination with mean climatic trends, on the vital rates of a generalist, wide ranging and K-selected medium-sized carnivore, has major implications for evolutionary ecology and conservation

Does public awareness increase support for invasive species management?:Promising evidence across taxa and landscape types

Management of invasive species often raises substantial conflicts of interest. Since such conflicts can hamper proposed management actions, managers, decision makers and researchers increasingly recognize the need to consider the social dimensions of invasive species management. In this exploratory study, we aimed (1) to explore whether species’ taxonomic position (i.e. animals vs. plants) and type of invaded landscape (i.e. urban vs. nonurban) might influence public perception about the management of invasive species, and (2) to assess the potential of public awareness to increase public support for invasive species management. We reviewed the scientific literature on the conflicts of interest around the management of alien species and administered two-phased questionnaires (before and after providing information on the target species and its management) to members of the public in South Africa and the UK (n = 240). Our review suggests that lack of public support for the management of invasive animals in both urban and non-urban areas derives mainly from moralistic value disagreements, while the management of invasive plants in non-urban areas mostly causes conflicts based on utilitarian value disagreements. Despite these general trends, conflicts are context dependent and can originate from a wide variety of different views. Notably, informing the public about the invasive status and negative impacts of the species targeted for management appeared to increase public support for the management actions. Therefore, our results align with the view that increased public awareness might increase the public support for the management of invasive species, independent of taxonomic position and type of landscape

Desertification and global change

Arid and semiarid regions cover one third of the continental areas on Earth. These regions are very sensitive to a variety of physical, chemical and biological degradation processes collectively called desertification. Although interest in desertification has varied widely in time, there is a renewed concern about the evolution of dryland ecosystems because (1) a significant fraction of existing drylands already suffers from miscellaneous degradation processes, (2) increasing populations will inevitably result in further over-utilization of the remaining productive areas, (3) climatic changes expected from the greenhouse warming might result in drier continental interiors, and (4) some of the desertification processes themselves may amplify local or regional climatic changes. This paper reviews some of the many aspects of this issue in the context of the Global Change research program.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/43891/1/11258_2004_Article_BF00036043.pd

The mammals of Angola

Scientific investigations on the mammals of Angola started over 150 years ago, but information remains scarce and scattered, with only one recent published account. Here we provide a synthesis of the mammals of Angola based on a thorough survey of primary and grey literature, as well as recent unpublished records. We present a short history of mammal research, and provide brief information on each species known to occur in the country. Particular attention is given to endemic and near endemic species. We also provide a zoogeographic outline and information on the conservation of Angolan mammals. We found confirmed records for 291 native species, most of which from the orders Rodentia (85), Chiroptera (73), Carnivora (39), and Cetartiodactyla (33). There is a large number of endemic and near endemic species, most of which are rodents or bats. The large diversity of species is favoured by the wide range of habitats with contrasting environmental conditions, while endemism tends to be associated with unique physiographic settings such as the Angolan Escarpment. The mammal fauna of Angola includes 2 Critically Endangered, 2 Endangered, 11 Vulnerable, and 14 Near-Threatened species at the global scale. There are also 12 data deficient species, most of which are endemics or near endemics to the countryinfo:eu-repo/semantics/publishedVersio