Diets of mammalian herbivores in Australian arid, hilly shrublands: seasonal effects on overlap between euros (hill kangaroos), sheep and feral goats, and on dietary niche breadths and electivities

The diets of euros or hill kangaroos (Macropus robustus), domestic sheep (Ovis aries) and feral goats (Capra hircus) in hilly, shrub rangeland in southern Australia were examined in a 12-year study. Levels of dietary overlap between these herbivores, their foraging in relation to resource availability, and the potential for competition in different conditions were also examined. The diet of euros was based around grasses. In dry seasons some shrubs were also eaten but in severe drought grass formed more than 80% of their diet. While grass was important to sheep in wetter conditions, they ate much shrub in dry conditions. Feral goats had broad diets but their preference for browse was high. In drought, euros had only a modest dietary overlap with sheep and goats. Data for dietary niche breadths and electivities pointed to only limited competition between the herbivores.     

The impact of rural land management changes on soil hydraulic properties and runoff processes: results from experimental plots in upland UK

To develop an evidence base to help predict the impacts of land management change on flood generation, four experimental sites were established on improved grassland used for sheep grazing at the Pontbren catchment in upland Wales, UK. At each site, three plots were established where surface runoff was measured, supplemented by measurements of soil infiltration rates and soil and vegetation physical properties. Following baseline monitoring, treatments were applied to two of the plots: exclusion of sheep (ungrazed) and exclusion of sheep and planting with native broadleaf tree species (tree planted), with the third plot acting as a control (grazed pasture). Due to a particularly dry summer that occurred pre‐treatment, the soil hydrological responses were initially impacted by the effects of the climate on soil structure. Nevertheless, treatments did have a clear influence on soil hydrological response. On average, post‐treatment runoff volumes were reduced by 48% and 78% in ungrazed and tree‐planted plots relative to the control, although all results varied greatly over the sites. Five years following treatment application, near‐surface soil bulk density was reduced and median soil infiltration rates were 67 times greater in plots planted with trees compared to grazed pasture. The results illustrate the potential use of upland land management for ameliorating local‐scale flood generation but emphasise the need for long‐term monitoring to more clearly separate the effects of land management from those of climatic variability. Copyright © 2013 John Wiley & Sons, Ltd.     

Identification of rural land management signals in runoff response

Rural land management signals in catchment‐scale runoff have proven difficult to identify in general. The Pontbren experimental catchment in upland Wales, UK, provides a new data set with which to address this challenge. This data set includes more than 4 years of data from six tipping bucket rainfall gauges and eight stream flow gauges representing different land management regimes at different scales. Data‐based mechanistic rainfall–runoff models were fitted to this data set using the CAPTAIN toolbox. The spatial and temporal variabilities of model parameters were identified and interpreted where possible. The analysis highlighted a dependency between the modelled residence time and the presence of agriculturally improved grassland, which produced a flashier response than grassland in a more natural condition. Another factor found to strongly affect the spatial variability of runoff response was the presence of lakes, while catchment area had a less pronounced effect, and the influence of trees, steepness and soil type could not be identified. Some time variability of response was observed but this was not consistent across the catchment and could not easily be interpreted. Copyright © 2010 John Wiley & Sons, Ltd.     

Nitrogen and phosphorus in New Zealand streams and rivers: Control and impact of eutrophication and the influence of land management

Abstract

Given sufficient light and heat, the growth of aquatic macrophytes and algae associated with eutrophication is generally controlled by the concentration, form and ratio between nitrogen (N) and phosphorus (P). Data from 1100 freshwater sites monitored for the last 10 years by New Zealand's regional councils and unitary authorities were assessed for streams and rivers with mean nitrate/ nitrite‐N (NNN), dissolved reactive P (DRP), total N (TN) and total P (TP) concentrations in excess of New Zealand guidelines, and to generate a data set of N:P ratios to predict potential periphyton response according to the concentration of the limiting nutrient. The frequency of sites exceeding the guidelines varied from 0 to 100% depending on the parameter and region, but South Island regions were generally more compliant. The dissolved inorganic N (DIN) to dissolved reactive P (DRP) ratio was used to group data into three nutrient limitation classes: <7:1 (N‐limited), between 7:1 and 15:1 (co‐limited), and>15:l (P‐limited), by mass. P‐limitation was the most frequent scenario in New Zealand streams (overall, 76% of sites were P‐limited, 12% N‐limited, and 12% co‐limited). The mean concentration of the limiting nutrient for each site was combined with empirical relationships to predict periphyton densities (the average of N‐and P‐limited growth was used for sites with co‐limitation). This assessment predicted that 22 sites were likely to exceed the periphyton guideline for protecting benthic biodiversity (50 mg chlorophyll a m^?2), but this assessment is likely to be highly changeable in response to climatic conditions and present and future land use. As an example, we modelled N and P losses from an average sheep and a dairy farm in Southland (South Island, New Zealand) in 1958, 1988, 2008 and 2028. We predicted that with time, as farm systems have and continue to intensify, N losses increase at a greater rate than P losses. Since the pathway for N to reach fresh waters may be more tortuous and take longer than P to reach a stream or river, focusing mitigation on P losses may have a quicker effect on potential algal growth. In addition, with time, it is expected that P‐limitation in New Zealand's rivers and streams will be more widespread as N‐losses are unabated. Hence, although strategies to decrease N losses should be practised, mitigating P losses is also central to preventing eutrophication.     

RESTORATION OF SHEEP TRANSHUMANCE IN THE EBRO VALLEY,ARAGON, SPAIN*

For centuries, sheep transhumance has connected the Spanish highlands with the lowlands, creating a livestock system with important social, economic, cultural, and landscape effects. About 5 million sheep were involved in transhumant movements in the mid‐1700s, but transhumance started to decay in the nineteenth century and almost disappeared in the 1970s and 1980s. In the 1980s, transhumant sheep did not number more than 25,000 in the study area; at present the number exceeds 134,000, with herders practicing both descending and ascending transhumance. In this article we provide information not only on current numbers of transhumant sheep but also on the origins and destinations of the flocks. We also confirm that the reputation of transhumance, once regarded as quaint and antiquated, has been enhanced by the ecosystem services it provides and by the cultural and heritage continuities it renders.     

ALPINE AREAS IN THE COLORADO FRONT RANGE AS MONITORS OF CLIMATE CHANGE AND ECOSYSTEM RESPONSE*

ABSTRACT. The presence of a seasonal snowpack in alpine environments can amplify climate signals. A conceptual model is developed for the response of alpine ecosystems in temperate, midlatitude areas to changes in energy, chemicals, and water, based on a case study from Green Lakes Valley–Niwot Ridge, a headwater catchment in the Colorado Front Range. A linear regression shows the increase in annual precipitation of about 300 millimeters from 1951 to 1996 to be significant. Most of the precipitation increase has occurred since 1967. The annual deposition of inorganic nitrogen in wetfall at the Niwot Ridge National Atmospheric Deposition Program site roughly doubled between 1985–1988 and 1989–1992. Storage and release of strong acid anions, such as those from the seasonal snowpack in an ionic pulse, have resulted in episodic acidification of surface waters. These biochemical changes alter the quantity and quality of organic matter in high‐elevation catchments of the Rocky Mountains. Affecting the bottom of the food chain, the increase in nitrogen deposition may be partly responsible for the current decline of bighorn sheep in the Rocky Mountains.     

甘肃省肉羊产业组织模式选择的影响因素

基于200家肉羊养殖户的实地调查数据,运用多元logistic计量经济模型,从养殖户户主特征、生产经营特征、养羊投入和政府扶持4个方面分析了肉羊产业组织模式选择的影响因素。结果表明：从养殖户角度来看,政府扶持和生产经营特征是影响养殖户组织模式选择行为的主要因素。其中政府扶持中政府补贴、协会合作社的建立对养殖户组织模式的选择影响作用最大;生产经营特征中饲养规模、养殖收入、销售方式的影响作用次之。养殖户户主特征中的文化程度和养羊投入中种羊来源、饲草料供给、劳动力投入的影响显著水平较低,影响作用较小,其余的因素对养殖户的选择行为没有影响作用。     

辽宁省建平县水泉遗址动物考古研究——兼论距今4000年前后北方长城沿线地区动物资源的利用策略

作为草原丝绸之路的起点,辽西地区也是中华文明的起源地之一.文章对辽宁省建平县水泉遗址出土的动物骨骼进行了鉴定和分析.结果 表明,在出土的409件可鉴定脊椎动物骨骼中,家猪(Sus domesticus)骨骼可鉴定标本数(NISP)占比为63.75％(最小个体数(MNI)为14件,占比35.90％),显示家猪为水泉遗址夏...     

磁敏感加权成像对羊脑静脉血管的实验研究

目的:探讨超高场强磁共振SWI对脑静脉血管的检出率和诊断价值。方法:选取5只健康绵羊,然后对羊脑部静脉血管进行3.0T超高场强磁共振成像,对磁共振成像所得T1WI、T2WI及SWI图像进行对比分析。结果:分析所得T1WI、T2WI及SWI图像,将额部脑浅静脉在MRI图像上的表现分为4级(Ⅰ-未显示,Ⅱ-显示模糊,Ⅲ-显示较清楚,Ⅳ-显示清楚),在20支脑静脉血管中,SWI显示Ⅲ级共2支血管,Ⅳ级共18支血管,无I级和Ⅱ级血管显示。结论:超高场强磁共振SWI序列对检测脑静脉血管具有重要价值。     

A new zoogeography of domestication and agricultural planning in Southern Ghana

Animal behaviour is vital for livestock choices, but is less researched in West Africa than economic considerations. An animal geography framework is applied to the socio-economic context of livestock behaviour in coastal Ghana, assessing the shared 'actant' behaviour of people and animals, and the contribution of such a study to animal geography and agricultural knowledge. Data were gathered on cattle, sheep and goat behaviour and the impact of these on human livelihoods, perceptions and the socio-environmental context. Animal behaviour was more important in the choice of livestock species, but economic considerations were more important in the decision to acquire animals. Goats had more incidents with people in village centres than sheep and cattle. Cattle had more incidents in farmland and grassland than goats and sheep. Women and young people were more affected by livestock behaviour. These findings increase the understanding of livestock zoogeography and livelihood decisionmaking, and contribute to animal geography by documenting the relevance of individualised gender- and age-based human behaviour, as well as intra- and inter-species animal behaviour to a shared actancy perspective, and a more dynamic zoogeography.