Long-term effects of hedgerow management policies on resource provision for wildlife

Hedgerows provide important habitat and food resources for overwintering birds, mammals and invertebrates. Currently, 41% of managed hedgerow length in England forms part of three Agri-Environment Scheme (AES) options, which specify a reduction in hedgerow cutting frequency from the most common practice of annual cutting. These AES options aim to increase the availability of flowers and berries for wildlife, but there has been little rigorous testing of their efficacy or estimates of the magnitude of their effects. We conducted a factorial experiment on hawthorn hedges to test the effects of (i) cutting frequency (every 1, 2 or 3 years) and (ii) timing of cutting (autumn vs. winter) on the abundance of flowers and berry resources. Results from 5 years show that hedgerow cutting reduced the number of flowers by up to 75% and the biomass of berries available over winter by up to 83% compared to monitored uncut hedges. Reducing cutting frequency from every year to every 3 years resulted in 2.1 times more flowers and a 3.4 times greater berry mass over 5 years. Cutting every 2 years had an intermediate effect on flower and berry abundance, but the increase in biomass of berries depended on cutting in winter rather than autumn. The most popular AES option is cutting every 2 years (32% of English managed hedgerow length). If these hedges were managed under a 3 year cutting regime instead, we estimate that biomass of berries would increase by about 40%, resulting in a substantial benefit for wildlife.     

A comparison of geographical and neighbourhood models for improving atlas databases. The case of the French butterfly atlas

We use data from the French national butterfly atlas to compare the potential of direct geographical and neighbourhood models to account for numbers of species and incidence of species in French départements. Direct geographical models use data on latitude, longitude and altitude, whereas neighbourhood models use information from adjacent areas. Both geographical models and neighbourhood models account for a large proportion of the variance in species richness (68-78%). However, neighbourhood models are more successful than models based solely on simple geographical variables. A large number of individual species distributions are accounted for by logistic and autologistic regression models (222 of 246 species, 90.2%). The autologistic models incorporate information on neighbouring areas. The exceptions are rare species, five of six of which occur in a single administrative unit only (2.4%), or virtually ubiquitous species found in >90% of units (7.3%). Autologistic models dominate logistic models in accounting for species incidences using stepwise logit regressions, neighbourhood variables appearing in 64.5% of successful species models (absent in 22.8%) and then always entering first. A simple neighbourhood (distance-unweighted) measure (C₂) dominates more models (89 of 246 species, 36.2%) than a distance-weighted neighbourhood measure (C₁; 77 of 246 species, 31.3%). The models are here demonstrated to be potentially valuable for identifying under-recording and losses from regional extinction and for filling gaps in recording. The findings reveal substantial, apparent, losses of species in western and northern France as well as substantial discrepancies (differences) in numbers of species, for some administrative units (départements) and for both post-1970 and total records, compared with numbers predicted to occur. We use two distinct approaches on total species and individual species to provide comparative estimates of the numbers of species expected within spatial units and we present the number of additional units in which species are expected to occur. The probabilities for these species in French départements are available on Web site: http://www.brookes.ac.uk/schools/bms/research/data/ecology/butterfly.html.     

Potassium-salinity interactions in irrigated corn

Summary Potassium uptake by plants can be affected by high salinity and the Na concentration in the soil solution. There is abundant evidence that Na and the Na/Ca ratio affects K uptake and accumulation within plant cells and organs and that salt tolerance is correlated with selectivity for K uptake over Na. This provides the basis for hypothesis which exists in the literature and was examined in this study, that K application can reduce salinity damage to plants. The main objectives of this study were to: (i) study the effects of salinity and K fertilization interactions on corn yield and nutrient uptake; (ii) test the possibility that salinity damage can be reduced by elevating K fertilization rate; and (iii) study K dynamics in soil as a function of the salinity of the irrigation water, in soils with high and low indigenous potassium. The response of corn (Zea mays (L.) cv. Jubilee) to K fertilization under saline and non-saline conditions was studied by growing corn in two soil types in a pot experiment. Rates of K application to a 3 kg pot were: 0, 15 and 30 mmol K to the Gilat soil and 7.5, 15 and 30 mmol K to the Nordiya soil as KCl. The desired quantity of K was applied in one dose after seedling emergence. The salinity levels of the irrigation water were 4, 20 and 40 mmol charge 1^–1. The irrigation was applied at least every second day and in excess to avoid water stress and to ensure drainage. Increased salinity in the irrigation water significantly decreased yield in both soils. Potassium significantly increased yield at all salinity levels only in the sandy soil which had a low natural level of K, but there was no difference in the relative yield decrease with salinity increase between the lowest and highest K application rates. Potassium fertilization did not eliminate the deleterious effects of salinity on corn yield despite its beneficial effect of increasing K content and reducing the NaK ratio in plant tissue. Potassium uptake by plants was the major factor in K dynamic processes. Potassium adsorption, release and fixation were secondary factors while leaching was an insignificant factor in overall K balance under cropping conditions.     

Storage temperature for maintenance of internal quality in Idaho Russet Burbank potatoes

Idaho-grown Russet Burbank potatoes treated with a sprout inhibitor were stored at 42 F, 45 F, and 48 F for 11 months. Monthly quality evaluations showed that tubers stored at 42 F were less mealy, contained more reducing sugars, and were yellower in color than those stored at 45 F or 48 F. The latter two treatments were not significantly different in mealiness and were generally similar in yellowness of color. Tubers stored at 48 F had less reducing sugars than those stored at 45 F. Although all treatments resulted in a gradual darkening of the potatoes during storage, differences in grayness among the three storage treatments were minor from a practical standpoint. It is suggested that a storage temperature no lower than 45 F be used to maintain the internal quality of Russet Burbank potatoes.     

Barn owl release in lowland southern England—a twenty-one year study

Twenty-one years of carefully documented barn owl (Tyto alba) study and release in England by the South Midlands Barn Owl Conservation Group (SMBOCG) have necessitated a re-examination of some of the premises on which such release schemes are judged. Fifteen years after the first releases, the number of independently breeding owls (i.e. breeding ‘wild’ or ‘as though wild’) in a 1200 km² study area is still increasing sharply and now far exceeds the number released in any one year, with the rate of increase outstripping the cumulative number of release events. Ringing returns indicate that fledged young dispersed further than adults, and that released adults which immediately deserted their release sites were less likely to survive their first 30 days than those staying in the vicinity of their release, where they could take advantage of supplementary feeding. Artificial feeding at release sites led to pellets containing lower liveweight equivalent of wild-caught prey but higher numbers of fledged young. Otherwise, and importantly, no significant difference in survival, mortality, dispersal, foraging success or breeding success was found between wild/independent owls and various categories of released bird. Availability of field vole habitat was not as important for barn owl breeding success as was found in previous studies, with owls able to replace this species in their diet with the less habitat-specific wood mouse. Evidence is provided that starvation was not as important a cause of mortality as has been proved elsewhere. Although barn owl nests often occurred in extreme close proximity, breeding density had no effect on either foraging or breeding success. The possible genetic consequences of barn owl release in Britain are briefly discussed. Very few barn owl release schemes have attempted to prove that their work is worthwhile, so long-term, well-documented studies such as that presented here are vital in establishing some of the principles involved in releasing barn owls into the wild.     

坏死性肠炎对家禽业的持续性挑战

坏死性肠炎是能造成较大经济损失并且不利于动物福利的一种禽病。由于欧盟出台了禁用抗生素促生长剂以及禁止在饲料中添加动物副产品的规定,该病在欧洲地区的流行日益加剧。坏死性肠炎的发病率差异较大(1%～40%),而且临床症状不明显是该病的一个重要特征,经常导致不能及时确诊和治疗,造成了极大的损失。本文探讨了各种因素如环境、健康以及饲料等如何影响肠道内环境并促进C型产气荚膜梭菌的增殖。针对这种受多因素影响的疾病,建立起可供研究细菌与宿主互作的高效并且可复制的实验模型显得尤为重要,这些模型将为在家禽业中探索合理的疾病控制或管理方法提供重要的工具。