RELATIONSHIPS BETWEEN CHANGES IN HABITAT CONDITIONS AND POPULATION DENSITY OF AN INTRODUCED POPULATION OF SIGNAL CRAYFISH (PACIFASTACUS LENIUSCULUS IN A FLUVIAL SYSTEM.

After the disappearance of the native crayfish in many rivers in Biscay, Basque Country, Spain, the signal crayfish Pacifastacus leniusculus was introduced in the main fluvial stretches and several breeding populations have established. One of the most productive zones was the Cadagua River, where the population was established from 1989 (first introduction) to 1995. Starting from that year, a marked decrease in population was recorded downstream, and this fact is studied in relation to fluctuations in physical and chemical conditions caused by human perturbations in the fluvial corridor mainly caused by the construction of a road

Modelling the habitat of a wild ungulate in a semi-arid Mediterranean environment in southwestern Europe: Small cliffs are key predictors of the presence of Iberian wild goat

After a drastic contraction in the species' range, the Iberian wild goat Capra pyrenaica (Schinz, 1838) has recolonized semi-arid steppe areas where the availability of resources is lower than it is in the species typical habitat. There is a gap in the habitat characteristics that allow the species to survive in an environment that lacks high cliffs and rocky outcrops. We hypothesize that microhabitat characteristics allow the species to find the resources necessary for survival in atypical areas. To test that, we measured several topographic variables (slope, distance to small cliffs and elevation) as well as land use/cover variables (distance to bushes, forests, agriculture, artificial and rivers). To model the habitat in the Middle Ebro Valley, Spain, we used data from 7-yr of monitoring of the species in an averaged-model with Generalized Linear Mixed Model (GLMM-Logit). Distance to small cliffs and distance to bushes explained most of the variance in the model which reflected a fragmented potential habitat. The fragmented structure of the habitat which might act as a metapopulation system, and the spatial configuration of fragments along rivers might act as corridors that favour the dispersal should be taken in consideration in the conservation and management of the species

First characterization of the ecotoxicity of paraffin particles: assessment of biochemical effects in the marine polychaeteHediste diversicolor

Plastics are a widespread environmental problem, particularly in the form of small particles or fragments (microplastics). With the purpose of gradually replacing the use of plastics in cosmetic products (primary microplastics), the use of paraffin in microspheres has recently been applied. Paraffin waxes are composed by organic molecules usually derived from petroleum, thus assumed to be chemically and biologically inert, having a lower (eco)toxicity and residence time compared with plastic particles. However, the low ecotoxicity of paraffin waxes may be somewhat questionable, because some paraffin constituents can be absorbed and catabolized, thus exerting biological effects. The main objective of this study was to understand the potential toxic effects of paraffin microparticles on key physiological processes of the polychaeteHediste diversicolor. To attain this objective, this work assessed the acute and chronic effects of three densities (5, 20, and 80 mg L-1) of four size ranges of paraffin particles (from 100 to 1200 mu m) on this epibenthic organism. Although paraffin wax can be generically considered innocuous, the present study was able to demonstrate a significant inhibition in the activity of acetylcholinesterase in acutely exposed organisms and an increase in the activity of glutathione peroxidase, catalase, and glutathione S-transferase under some specific scenarios.Bruno Nunes is hired by "ECO-R-pharmplast Ecotoxicity of realistic combinations of pharmaceutical drugs and microplastics in marine ecosystems", Fundacao para a Ciencia e aTecnologia, FCT (reference POCI-01-0145-FEDER-029203). This research was financially supported by CESAM(UIDB/50017/2020+UIDP/50017/2020), by FCT/MCTES through national funds (PIDDAC), and by the co-funding by the FEDER, within the PT2020 Partnership Agreement and Compete 2020