Selection of woody species for wastewater enhancement and restoration of riparian woodlands

Growth and nutrient uptake of seven tree species were evaluated with the goal of selecting the species that can be used for wastewater enhancement by dendro-purification, or green tree filtering, and for restoration of riparian woodlands. Trees were grown in pots with an inert mixture of perlite and vermiculite and irrigated with either nutrient solution or treated wastewater We measured the effects of species and irrigation water on biomass and nutrient content of leaves, stems and roots. For most of the species, treated wastewater had a positive effect on final biomass and above ground: below ground ratio compared to that of nutrient solution. However, growth of Cupressus sempervirens and Populus nigra were inhibited by water sodium concentration. Nerium oleander, Tamarix africana and Vitex agnus-castus were the species with the greatest final biomass. Pistacia terebinthus had the highest nitrogen and phosphorus content in leaves, stems and roots, while N. oleander and V. agnus-castus showed the best potassium accumulation. In general, P. terebinthus, N. oleander, T. africana and V. agnus-castus were the best qualified species for purification of wastewater.     

Multiple data sources improve DNA-based mark-recapture population estimates of grizzly bears.

A fundamental challenge to estimating population size with mark-recapture methods is heterogeneous capture probabilities and subsequent bias of population estimates. Confronting this problem usually requires substantial sampling effort that can be difficult to achieve for some species, such as carnivores. We developed a methodology that uses two data sources to deal with heterogeneity and applied this to DNA mark-recapture data from grizzly bears (Ursus arctos). We improved population estimates by incorporating additional DNA "captures" of grizzly bears obtained by collecting hair from unbaited bear rub trees concurrently with baited, grid-based, hair snag sampling. We consider a Lincoln-Petersen estimator with hair snag captures as the initial session and rub tree captures as the recapture session and develop an estimator in program MARK that treats hair snag and rub tree samples as successive sessions. Using empirical data from a large-scale project in the greater Glacier National Park, Montana, USA, area and simulation modeling we evaluate these methods and compare the results to hair-snag-only estimates. Empirical results indicate that, compared with hair-snag-only data, the joint hair-snag-rub-tree methods produce similar but more precise estimates if capture and recapture rates are reasonably high for both methods. Simulation results suggest that estimators are potentially affected by correlation of capture probabilities between sample types in the presence of heterogeneity. Overall, closed population Huggins-Pledger estimators showed the highest precision and were most robust to sparse data, heterogeneity, and capture probability correlation among sampling types. Results also indicate that these estimators can be used when a segment of the population has zero capture probability for one of the methods. We propose that this general methodology may be useful for other species in which mark-recapture data are available from multiple sources.     

Proposal for new quantitative eco-design indicators: a first case study

Eco-design is a valuable approach in order to reduce the environmental impact associated with a product system, by introducing environmental considerations early on in its design. Different strategies are possible for the implementation of eco-design, depending on the intended goals as well as the characteristics of the products. The present work proposes a series of eco-design indicators and tests to what extent the application of these simple indicators provides a reliable indication of the reduction of environmental impact, as measured by commonly employed Life Cycle Impact Assessment (LCIA) indicators. The product chosen for the case study was a water source heat pump. Two of the newly-developed indicators were applied and compared to LCIA indicators, focussing on design for disassembly and for recycling. A good and robust correlation was found, providing support to the thesis that these simple eco-design indicators can be used as a proxy to quickly and effectively gauge the environmental improvements introduced in a product system at the design stage.     

Isotopic evidence of natural uranium and spent fuel uranium releases into the environment

Uranium and plutonium isotopes were measured in soils, sediments and waters in an area subject to the past and present discharges from the uranium conversion plant of Malvési (France). The isotopes (236)U and (239)Pu are well known activation products of uranium and they prove to be powerful tracers of spent fuel releases in soils and sediments. On the other hand (234)U and (238)U activities measured in waters can be used to distinguish between releases and background uranium sources. Such findings contribute to improve the monitoring of the actinides releases by nuclear fuel facilities (mining sites, conversion, enrichment and fuel plants, reprocessing plants).     

Persistent Detection of Cosavirus and Saffold Cardiovirus in Riachuelo River,Argentina

Food and Environmental Virology - Cosaviruses (CoSV) and Saffold cardiovirus (SAFV) are novel members of the Picornaviridae family. The Matanza-Riachuelo river basin covers a total area of 2200 km2...     

Consumer-resource body-size relationships in natural food webs

It has been suggested that differences in body size between consumer and resource species may have important implications for interaction strengths, population dynamics, and eventually food web structure, function, and evolution. Still, the general distribution of consumer-'resource body-size ratios in real ecosystems, and whether they vary systematically among habitats or broad taxonomic groups, is poorly understood. Using a unique global database on consumer and resource body sizes, we show that the mean body-size ratios of aquatic herbivorous and detritivorous consumers are several orders of magnitude larger than those of carnivorous predators. Carnivorous predator-prey body-size ratios vary across different habitats and predator and prey types (invertebrates, ectotherm, and endotherm vertebrates). Predator-prey body-size ratios are on average significantly higher (1) in freshwater habitats than in marine or terrestrial habitats, (2) for vertebrate than for invertebrate predators, and (3) for invertebrate than for ectotherm vertebrate prey. If recent studies that relate body-size ratios to interaction strengths are general, our results suggest that mean consumer-resource interaction strengths may vary systematically across different habitat categories and consumer types.