Survival of Marbled Teal (Marmaronetta angustirostris) released back into the wild

Reintroduction or re-enforcement programmes are major tools in species conservation, but there is a need for more studies that assess the influence of different husbandry and release methods on the survival of released animals. We investigated the survival of globally threatened Marbled Teal (Marmaronetta angustirostris) taken into captivity as ducklings when they became trapped in an irrigation channel, then released again after fledging. We used wing tags and mark-recapture models to estimate the survival of released teal. Ducklings rescued in 1996 (n = 53) were released soon after fledging in September and their survival was modelled for seven months until April 1997. Their apparent monthly survival rate (lower than true survival owing to loss of wing tags) was 0.85 ± 0.12 (±s.e.). Ducklings rescued in 1997 (n = 44) were released together in February 1998 over five months after fledging, and their survival was modelled for six months from February until August. Their apparent monthly survival rate was 0.54 ± 0.06. Ducklings rescued in 1998 (n = 159) were released in August-September soon after fledging and their survival was modelled for 10 months from August until June. Their apparent monthly survival rate was 0.83 ± 0.07. Monthly survival was significantly higher for the 1996 and 1998 cohort, suggesting that retaining birds in captivity after fledging had a negative impact on post-release survival. When birds were released in February, a lower proportion survived until the breeding season three months later than when they were released five months earlier in September.     

A statistical framework to combine multivariate spatial data and physical models for Hurricane surface wind prediction

Storm surge is the onshore rush of seawater associated with hurricane force winds. Storm surge can compound the effects of inland flooding caused by rainfall, leading to loss of property and loss of life for residents of coastal areas. Numerical ocean models are essential for predicting which coastal areas are most likely to be impacted by storm surge. These numerical physics-based models are driven primarily by the surface wind forcings which are currently specified by a deterministic formula. Although these equations incorporate important physical knowledge about the structure of hurricane surface wind fields, they cannot always capture the asymmetric and dynamic nature of a hurricane. This article develops a new multivariate spatial statistical framework to improve the estimation of these wind field inputs while accounting for potential bias in the observations. We find that this spatial model consistently improves parameter estimation and prediction for surface wind data for a case study of Hurricane Charley of 2004 when compared to the original physical model. These methods are also shown to improve storm surge estimates when used as the forcing fields for a numerical three-dimensional coastal ocean model.     

European reference method of in vivo determination of metabolisable energy in poultry: reproducibility, effect of age, comparison with predicted values

1. Apparent metabolisable energy corrected to zero-nitrogen retention (AMEn) was measured using the European reference procedure in 9 European laboratories. Seven pelleted diets were evaluated. AMEn was measured with adult cockerels and young birds. 2. Between-laboratory standard deviations were for dry matter (DM) 12.5 g/kg, gross energy 0.085 MJ/kg DM, Kjeldahl nitrogen 0.768 g/kg DM, AMEn (adults) 0.256 MJ/kg DM, and AMEn (young) 0.337 MJ/kg DM. Corresponding coefficients of variation between laboratories were 1.42, 0.45, 2.15, 1.88 and 2.60% respectively. 3. AMEn values of experimental diets were always significantly lower when measured with young birds. This effect was more pronounced when diets contained added fat. 4. Tallow or soyabean oil were incorporated into two basal diets at 40 g/kg inclusion rate. No significant differences were observed between AMEn values of either diet with adults or young birds, suggesting that AMEn energy values of these fats are indistinguishable at this inclusion rate. 5. Similar AMEn values were obtained in young birds by estimating nitrogen accretion, either by the difference between intake and excreta nitrogen or by measuring body weight gain. Determined AMEn values were very similar to those predicted using three different regression equations.     

Soil physical properties and wheat root growth as affected by no-tillage and conventional tillage systems in a Mediterranean environment of Chile

No-tillage systems affect soil properties depending on the soil, climate, and the time since its implementation. In heavy no-tilled soils a surface compacted layer is commonly found. Such layer can affect root growth and soil water infiltration. In several cases, surface organic carbon can buffer these problems. The aim of this study was to evaluate the effect of 4- and 7-year-old conventional (CT) and no-tillage (NT) treatments on soil physical properties, root growth, and wheat (Triticum turgidum L. var. durum) yield in an Entic Haploxeroll of Central Chile. In both tillage treatments we study soil water retention, bulk density (ρ_b), soil particle density (ρ_s), soil water infiltration, mean-weight diameter of soil aggregates (MWD), penetration resistance, grain yield, and root length density (L_v) up to a depth of 15 cm. The MWD and the penetration resistance were higher under NT as compared to CT. For the top 5 cm of soil, L_v was greater under NT as compared to CT. Differences of L_v between NT and CT were 2.09, 7.60, and 4.31 cm root cm⁻³ soil during the two leaves, flowering and grain filling phenological stages, respectively. Generally, the effect of NT on these properties was more evident near the soil surface. In contrast, fast drainage macropores, ρ_s, and soil water infiltration rates were higher under CT than under NT. Tillage treatments did not significantly affect ρ_b and yield. A longer time under no-tillage enhanced aggregate stability, however, other soil physical properties were negatively affected.     

Genetic diversity of Bolivian wild potato germplasm: changes during ex situ conservation management and comparisons with resampled in situ populations

Potato wild relatives are important sources of novel variation for the genetic improvement of the cultivated potato. Consequently, many natural populations have been sampled and were deposited as accessions in gene banks around the world. Here we investigate to what extent the genetic variation of Bolivian wild potato species is maintained under gene bank conditions and how this diversity relates to that of current in situ populations. For this purpose, materials from seven potato species were screened for microsatellite variation. Genetic changes between different generations of ex situ germplasm were not observed for Solanum leptophyes and S. megistacrolobum, but were detected for S. neocardenasii and S. okadae, while each of the species S. acaule, S. avilesii and S. berthaultii showed stability in some cases and genetic change in others. The observed changes were ascribed to genetic drift and contamination resulting from human error during regeneration. Re-collected populations of six of the studied species showed highly significant genetic differences with the ex situ accessions that, apart from changes during ex situ maintenance, are most likely to be attributed to sampling effects during collecting and in situ genetic changes over time. The implications of the results for ex situ and in situ conservation strategies of wild potato species are discussed.     

Ultrasonographic measurement of flow-mediated vasodilation in dogs with chronic valvular disease

ObjectivesTo measure flow-mediated vasodilation (FMD) in healthy dogs and in client-owned dogs with chronic valvular disease (CVD) and to investigate possible correlations between markers of CVD severity and FMD.AnimalsTwelve dogs with CVD and 11 healthy weight-matched dogs.MethodsBrachial artery FMD following 5 min inflation of a cuff around the antebrachium was measured in 12 dogs with CVD and 11 healthy weight-matched dogs. Measurements were also obtained in the healthy dogs 5 min after cuff placement but without inflation (‘sham cuff placement’). Dogs with CVD underwent echocardiography to confirm and characterize their disease.ResultsIn healthy dogs (median age 4 [2–6] years), median FMD was 7.7% versus 3.4% with sham cuff placement (P = 0.003). In dogs with CVD (median age 8 [4–16] years) median FMD was 5.5% versus 7.7% in healthy dogs (P = 0.131). FMD showed an inverse correlation with left ventricular end-diastolic diameter normalized for body weight (r = ?0.76, P = 0.0043).ConclusionsBrachial FMD in dogs with early CVD inversely correlates with severity of left ventricular remodelling.