Conventional perceptions of the interactions between people and their environment are rapidly transforming. Old paradigms that view humans as separate from nature, natural resources as inexhaustible or endlessly substitutable, and the world as stable, predictable, and in balance are no longer tenable. New conceptual frameworks are rapidly emerging based on an adaptive approach that focuses on learning and flexible management in a dynamic social-ecological landscape. Using two iconic World Heritage Areas as case studies (the Great Barrier Reef and the Grand Canyon) we outline how an improved integration of the scientific and social aspects of natural resource management can guide the evolution of multiscale systems of governance that confront and cope with uncertainty, risk, and change in an increasingly human-dominated world. 相似文献
Anti-cholinesterase insecticides constitute a major portion of modern synthetic pesticides and the assessment of cholinesterase (ChE) inhibition is widely used as a specific biomarker for evaluating the exposure of non-target organisms to these pollutants. However, most studies on this biomarker were developed on vertebrates and among invertebrates, gastropod mollusks are rarely used. Gastropods are important members of aquatic habitats and therefore present a high ecological relevance for freshwater ecosystems. In this context, ChE activities were characterized in two freshwater gastropod mollusks, Potamopyrgus antipodarum and Valvata piscinalis, in order to ascertain their value as sentinel species. Firstly, characterization of ChE activities was performed using different substrates (acetylcholine iodide, butyrylcholine iodide and propionylcholine iodide) and specific inhibitors (eserine, iso-OMPA and BW284c51). Secondly, in vivo effect of a widely used organophosphate insecticide, chlorpyrifos, was tested on ChE activity in both species. Results suggested that P. antipodarum possesses two isoforms of cholinesterases, one isoform which properties are intermediate between an acetyl and a propionyl ChE, and one minor isoform which correspond to a butyryl ChE, while V. piscinalis seems to possess only one isoform which displays typical properties of an acetyl ChE. Chlorpyrifos induced no effect on V. piscinalis ChE. In contrast, P. antipodarum activity was significantly decreased by environmental realistic chlorpyrifos concentrations (2.86 and 14.2 nM) after seven days of contact. The present study suggests that P. antipodarum may be employed as a biological indicator for assessing pesticide contamination. 相似文献
Microplastics are small-size plastic piece scales (particles <?5 mm) in sediments and waters which interact with environment and organisms by various means. Microplastics are becoming a universal ecological concern since they may be a source of hazardous chemicals to marine organisms and environments. Recent research suggests microplastics could enable the transfer of hydrophobic aquatic pollutants or chemical additives to biota. Even though microplastic presence and interactions are recently being detected in marine and freshwater systems, the fate of microplastics is still very poorly understood. This literature review is a summary of the sources and transport of microplastics, their interactions with toxic chemicals and the methodologies for chemical quantification and characterization of microplastics. The environmental outcome and impact of microplastics in wastewater treatment plants were assessed as well as the trends and update on microplastic research in the South African aquatic ecosystem.
Populations of adaptable mesopredators are expanding globally where passive rewilding and natural recolonization are taking place, increasing the risk of conflict with remaining livestock farmers. We analysed data from two social surveys of farmers in the Karoo, South Africa, where black-backed jackals (Canis mesomelas) and caracals (Caracal caracal) have re-emerged as a threat to sheep farms in the context of falling agricultural employment and the expansion of natural areas. We show that irrespective of measurement approach, lethal control of mesopredators in this fragmented socio-economic landscape was associated with increased livestock losses the following year. Terrain ruggedness was positively, and number of farmworkers negatively, associated with livestock losses. Our study provides further evidence that lethal control of mesopredators in this context is probably counter-productive and supports calls to develop, share and financially support a range of non-lethal methods to protect livestock, especially where natural recolonization of mesopredators is occurring. A graphical abstract can be found in Electronic supplementary material.
Plants evolve the production of wound-activated compounds (WACs) to reduce grazing pressure. In addition, several plant-produced WACs are recognized by various invertebrates, playing the role of infochemicals. Due to co-evolutionary processes, some invertebrates recognize plant infochemicals and use them to identify possible prey, detect the presence of predators or identify algae containing various classes of toxic metabolites. Different metabolites present in the same algae can play the role of toxins, infochemicals or both simultaneously. We investigated the infochemical activity of compounds extracted from three diatoms epiphytes of the seagrass Posidonia oceanica, by conducting choice experiments on invertebrates living in the same community or in close proximity. Furthermore, the specific toxicity of the extracts obtained from the same algae was tested on sea urchin embryos using a standard bioassay procedure, to detect the presence of toxins. The comparison of the two effects demonstrated that invertebrates are subjected to diatom wound-activated toxicants when these algae are not associated with their own habitat, but they are able to recognize volatile infochemicals derived from diatoms associated with their habitats. The specific toxicity of WACs was shown to be inversely correlated to the perceptive ability of invertebrates towards volatile compounds liberated by the same algae. Hence, when the recognition of specific algae by a given invertebrate species evolves, their detrimental effects on the receiving organism may be lost. 相似文献
Environmental Science and Pollution Research - In this study, the anthropogenic contamination in Trasimeno lake (Central Italy) was investigated using three sediment cores spanning over the last... 相似文献