Lead shot and teal (Anas crecca) in the Camargue, Southern France: Effects of embedded and ingested pellets on survival

The negative consequences of lead shot ingestion have been demonstrated in captive birds, and the prevalence of embedded shot has been measured in wild waterfowl several times. However, the long-term consequences of these two indirect outcomes of hunting on waterfowl survival have merely been investigated. Using data from about 40,000 X-rayed teals (Anas crecca), this study attempts to evaluate these effects. We used multivariate logistic regressions to model the probability of carrying shot in the flesh or in the gizzard while testing for various explanatory variables such as sex, age, time or morphological measures like mass and flattened wing length. Because of technical issues, we used a non-parametric sign test rather than a complete capture-recapture analysis to evaluate the effect of shot on teal survival. This test was applied to the differences in time between ringing and recovery for lead categories (no lead shot, ?1 shot in the flesh but none in the gizzard, ?1 shot in the gizzard but none in the flesh) compared two by two. We show that, overall, males are more likely to carry embedded shot than females whereas the latter are more likely to carry lead pellets in the gizzard. Similarly, adults are more likely to carry shot in the flesh whereas first year individuals are more likely to have pellets in the gizzard. Embedded shot tend to accumulate in the ducks body over time, i.e. with the number of encounters with hunters, with no significant effect on survival. Conversely, the probability of carrying shot in the gizzard decreases over time, because lead-poisoning quickly leads the individual to death. Several possible biological interpretations are put forward to explain those results. This study demonstrates that negative impacts of ingested lead on teal survival arise after only one single pellet is ingested, advocating the ban of lead ammunition.     

Seasonal variations in stem CO<Subscript>2</Subscript> efflux in the Neotropical rainforest of French Guiana

• Introduction  

Stem CO₂ efflux (E _s) is a significant component of total ecosystem respiration, but there is only scant information on seasonal variations in E _s in tropical rainforests and on the main factors explaining these variations.     

Conservation benefits of biological control: The recovery of a threatened plant subsequent to the introduction of a pathogen to contain an invasive tree species

Biological control using host-specific natural enemies is sometimes the only long-term and cost-effective option to contain dominant invasive alien species in natural ecosystems. To assess biocontrol success, most monitoring studies focus on the negative impacts of the released biocontrol agents on the target invasive species. Very few studies have shown the conservation benefits, i.e. their positive effects on the recovery of native species and habitats. A fungal pathogen (Colletotrichum gloeosporioides f. sp. miconiae) was successfully released on the island of Tahiti (South Pacific) to control the dominant invasive tree Miconia calvescens which forms dense monospecific stands in native rain- and cloud forests. The pathogen causes a leaf disease leading to partial (5–35%) defoliation of Miconia canopy trees. We studied the demographical parameters of the rare endemic sub-shrub Ophiorrhiza subumbellata, growing in the understory of montane cloud forests invaded by Miconia. We compared Ophiorrhiza populations in 13 plots set up in two sites located between 950 and 1000 m elevation, having the same Miconia invasion degree but different levels of leaf damage. Our results showed that, whereas the total population density of Ophiorrhiza is not affected, plants’ growth and fertility were significantly higher in more defoliated Miconia forests. A 3-year-long survey of Ophiorrhiza population at one study site indicated that the number of seedlings and juvenile plants increased, suggesting better recruitment and survival. This study demonstrates that biological control has contributed to the recovery of an endemic plant directly threatened by an invasive species, and may be considered as an important management tool for the partial restoration of native forests.     

RAD51C is required for Holliday junction processing in mammalian cells

During genetic recombination and the recombinational repair of chromosome breaks, DNA molecules become linked at points of strand exchange. Branch migration and resolution of these crossovers, or Holliday junctions (HJs), complete the recombination process. Here, we show that extracts from cells carrying mutations in the recombination/repair genes RAD51C or XRCC3 have reduced levels of HJ resolvase activity. Moreover, depletion of RAD51C from fractionated human extracts caused a loss of branch migration and resolution activity, but these functions were restored by complementation with a variety of RAD51 paralog complexes containing RAD51C. We conclude that the RAD51 paralogs are involved in HJ processing in human cells.     

Major discoveries on the dermal skeleton of fossil and Recent polypteriforms: a review

Following the discovery of the first living polypterid, Polypterus bichir, in 1802, almost two centuries later we now know of 15 living species (including four subspecies), 14 belonging to the genus Polypterus and one to the genus Erpetoichthys (Calamoichthys) all inhabiting intertropical Africa. The polypterid fossil record was for a long time reduced to some scarce, disarticulated bones, mainly scales, found in various African deposits covering a wider area than the actual geographical distribution. With the discovery, on one hand, of polypterid scales, vertebrae, dermal bones of the cranium and dorsal spiny rays in South America and, on the other hand, of scales and numerous dorsal spiny rays in Niger and Sudan, and two articulated fossils in Morocco, the story of the polypteriforms has revealed some of its mysteries. The discovery of isopedine between dentine and bony basal plate in the scales of living and fossil polypterid species is considered a synapomorphy of the group, and has been an important aid in discriminating polypterid scales from other ganoid scales. A review of the main findings during the last 20 years is presented.     

Impact of nutrition on nitrogen, phosphorus, Cu and Zn in pig manure, and on emissions of ammonia and odours

In order to reduce N, P and trace elements in pig manure, research toward a better agreement between supply and requirement has been undertaken in recent years, and ways to improve the biological availability of these elements in feedstuffs have been investigated. Substantial reduction in N excreted by pigs can be achieved by phase feeding combined with a better adjustment of the dietary amino acid balance. Feeding pigs with low N diets also allows a reduction of ammonia emission and to some extent the production of malodorous compounds. Phase feeding is also effective in reducing P excretion. However, low digestibility of P in feeds remains the main problem, although it is partly alleviated by the supplementation of pig diets with microbial phytase and the use of highly digestible mineral phosphates. In the same way, lowering Cu and Zn dietary supply is obviously an efficient way to reduce pigs' excretion of Cu and Zn. In a whole-farm perspective, improving the efficiency of nutrient utilisation by the animals is an efficient way to reduce import of nutrients from outside the farm and decrease the environmental risks.     

Didactic tools for supporting participatory water management in collective irrigation schemes

In many irrigation schemes, Water Users Associations (WUAs) acquired the responsibility for water management after withdrawal of the state. Based on the success of some indigenous irrigation schemes, it was assumed that farmers could easily become managers. As decision-making was the exclusive terrain of the governmental agencies that ran the schemes, farmers never gained the necessary experience with water management. Therefore, training of farmers and WUAs on the principles and processes of water management is essential. This paper demonstrates a practical example of training material on water management that incorporates research results on the process of Irrigation Management Transfer and resulting farmers’ water management for the case of the Office du Niger irrigation scheme. The results of the paper explain how input from research was used in the four steps of the construction of training material. These steps are (1) setting the training agenda, (2) selecting and adapting information to be featured, (3) targeting the audience and (4) designing the actual training material. A first validation of the approach and examples of the actual training material were obtained in a workshop uniting all stakeholders.