Effects of landscape complexity on farmland birds in the Baltic States

Data on birds occurring in farmland in the Baltic States of Estonia, Latvia and Lithuania were related to the spatial organisation of farmed habitats in three different agricultural landscape types. Species richness, abundance, and diversity of farmland bird communities, as well as abundance of the most frequently observed species were positively related to the number of residual non-cropped elements within farmland, the local mixture of annual crop and grass fields, and the variety of field types. The positive association of the species richness and abundance of the farmland bird community with richness in residual habitats and crops was most prominent in open landscapes. The results suggest that, by simplifying farmland structure and making it more homogenous, EU agricultural policies will have a detrimental effect on farmland bird populations in Eastern Europe. Ways of better targeting of the agri-environment schemes are suggested.     

Influence of conservation tillage on winter bird use of arable fields in Hungary

Bird use of conservation tillage-established (CT—seedbed preparation without soil inversion) crops was assessed at two adjacent sites in western Hungary, in comparison with conventionally established (mouldboard ploughed—P) fields. Bird abundance was assessed in a typical rotation of spring-sown maize and winter wheat in three consecutive winters. In the first winter, several species and the guild of seed-eating passerines were significantly more abundant on CT established plots, in both crop types. In the second winter, only starlings were more abundant on CT plots. In the third winter, only skylarks favoured CT over P plots. In combination with agri-environment scheme measures designed to provide resources for biodiversity, conservation tillage could play a role in softening the impact of agriculture on farmland birds in Hungary and elsewhere in Eastern Europe, in addition to its potential for reducing soil erosion and diffuse pollution.     

Breeding birds in short-rotation coppices on farmland in central Sweden—the importance of Salix height and adjacent habitats

Plantations of short-rotation coppice (SRC) have a potential for being a useful measure to stop the ongoing impoverishment of farmland biodiversity by increasing structural diversity, and decreasing cultivation intensity and use of pesticides in intensively managed farmland landscapes. The aim of this study was to investigate the relative importance of the structure of the plantation and composition of adjacent habitats for breeding birds in 41 SRCs (meansize±S.E.=9.4±1.6 ha). Mean number of species per ha in the SRCs was 2.8±0.3 species and there were more farmland birds (32 species, 808 territories) than forest birds (22 species, 400 territories). A major result of the present study was the strong influence of adjacent habitats on bird community composition (18 of 22 analysed species affected). There were large differences in bird communities between forest-bordered and open-bordered sites, but occurrence of residual habitats (i.e. other habitats than forest, pastures, shrub areas and arable fields) was also associated with occurrence of several species. The second factor of major importance for the bird fauna was the height of the plantations. Most species (14) were associated with tall plantations (>2 m), seven species were associated with plantations of intermediate (1–2 m) height, and six species were associated with plantations of low height (<1 m). A comparison of ecological traits between species classified as preferring SRC and species classified as avoiding SRC suggests that nest height was the only ecological character associated with a preference for Salix habitats, i.e. species with nests on the ground or in shrubs were more abundant in Salix habitats than in farmland landscapes in general. However, a broad spectrum of species was found in the SRCs and many of these seemed to be dependent on habitat features outside the plantations. Planting of Salix in intensively managed farmland plains will have positive effects on bird diversity by increasing the structural diversity of the landscape. In contrast, plantations on infields in forest-dominated landscapes will have negative effects, since the mosaic structure (i.e. mixture of open and forested habitats) positive for most farmland birds will disappear, and Salix plantations favour relatively few forest species. Additionally, Salix could be planted along sharp edges between coniferous plantations and open farmland in order to increase the complexity of the ecotone in intensively managed forest-farmland landscapes.     

Winter bird use of seed-rich habitats in agri-environment schemes

To assess the effectiveness of over-winter seed provision by agri-environment schemes, bird use of patches of seed-bearing crops was compared with that of other seed-rich habitats on 53 farms in eastern Scotland over three winters. Seed-bearing crops were the most frequently selected habitat, and held 28% of birds of the 10 species recorded. Outside schemes, cereal stubble was the most selected habitat and held 44% of birds. For nine species, seed-bearing crops were used by more birds than expected from the area of crop available in at least one winter, and five species were more likely to occur in first-winter patches, reflecting a greater abundance of cereal grain than in second-winter patches. For cereal grain specialists such as buntings, sowing cereal-based crops annually would ensure that grain is available in each winter, whilst either a 1-year or a 2-year crop would be appropriate for finches that favour oilseeds, and species with a more generalist diet.     

随机森林算法在新疆物种丰富度影响因素研究中的应用

基于多源遥感数据及其产品,以2010年新疆地区鸟类与哺乳动物物种丰富度空间分布数据为基础,结合土地利用、植被、气候、地形等遥感数据产品,探讨了影响新疆地区鸟类和哺乳动物物种丰富度的各环境因子空间分布及其差异.通过随机森林算法对影响鸟类和哺乳动物种数的环境解释变量进行了重要性评估,同时采用探索性回归分析对物种丰富度与环境因子的关系进行建模,比较了鸟类和哺乳动物在草地、林地和耕地三种生境中的主要环境影响因子及其差异.结果显示：影响物种丰富度的环境因子中,植被生长状态与能量转换能力对鸟类丰富度十分重要,且草地的海拔高度重要性最高,为38.38%;耕地所处的气候类型对鸟类丰富度有明显影响,其中年均温重要性达到32.98%;哺乳动物的三种生境选择中气候和海拔条件十分重要,共占重要性的60%以上,最高达76.85%,在耕地中哺乳动物更看重气候而非植被生长情况;三种生境中鸟类和哺乳动物的最优模型及其影响因子均不同,耕地对于鸟类、林地对于哺乳动物的模型解释力最高,分别为69.9%和68.9%,随机森林和探索性回归分析均显示年均温、年降水量和海拔高度是哺乳动物丰富度差异的重要解释因子.     

Set-aside management: How do succession, sowing patterns and landscape context affect biodiversity?

European Union (EU) member states set aside between 5 and 15% of arable land during the last two decades, but abolition of the set-aside scheme in 2008 caused a sudden loss in habitat availability and biodiversity in agricultural landscapes. Management of set-aside has many facets and in this perspective paper we focus on the biodiversity effects of successional age, sowing strategies and landscape context. Young, 1-2-year-old set-asides have been initially considered to be too ephemeral to have any conservation value. However, when a rich seed and bud bank is available, a species-rich natural (secondary) succession can be observed. Arable (annual) weed communities in the first two years of succession can even include endangered plant species with associated rare insect consumers. Furthermore, many bird species benefit from early-successional habitats, whereas small mammal communities are richer in older habitats. If the local plant species pool is poor, sowings of diverse mixtures from regional seed collections can be recommended. Set-aside managers using species-rich sowings often experience that dominant weeds suppress the less competitive annual species. This trend to species-poor communities can be avoided by intraspecific aggregation of competitively weak species. Broadening the spatial scale from the plot to the landscape, efficiency of set-aside is highest in simple landscapes, where set-aside exhibits greatest effect in enhancement of biodiversity and associated services such as pollination and biological control. In complex landscapes, however, additional set-aside does not add much to the high level of biodiversity and ecological processes already present. Twenty percent of semi-natural, non-crop habitat appears to be a rough threshold for enhancing biodiversity and sustaining services such as pollination and biological control, but improved set-aside management should have the potential to reduce the percentage of semi-natural non-crop habitat needed. EU policy should tailor set-aside schemes for the maintenance of biodiversity and also consider that management efficiency is higher in simple than complex landscapes.     

Effects of crop diversification and low pesticide inputs on bird populations on arable land

This 6-year experimental study measured the response of bird populations and abundance to combinations of mixed cropping and low pesticide regimes associated with a commercial crop rotation. The results show a rapid and sustained population increase among a wide range of bird species, in contrast to local regional trends for the same species. Seventy percent of the increase occurred within the first 3 years of the experiment, with species of high conservation concern, and those monitored as environmental indicators on lowland farmland in the UK, increasing on average, by 30% and 20% respectively (reaching respective peaks of 44% and 33% after 4 years). For some individual species, the increase was higher still, i.e., 300% (1–4 pairs) for grey partridge (Perdix perdix) and 46% (13–19 pairs) for skylarks (Alauda arvensis) in peak years. The results demonstrate that bird species typical of lowland arable farmland in the UK are responsive to suitable farm-scale changes in habitat and food provision (roughly, manipulation within less than 1-km²). They show that the carrying capacity of modern, commercially viable, arable farmland can be increased significantly for birds, in this case, mainly by using crops mosaics to create habitats alongside the appropriate use of herbicides on non-cropped habitats.     

我国鸟类特有种地理分布与气候要素关系的初步分析

分析了我国鸟类特有种与气候要素的关系. 结果表明:我国鸟类特有种中,分布区狭窄的有63种,分布区广泛的有8种,其中呈不连续分布的有38种,连续分布的有33种,留鸟有67种,候鸟有4种;大部分地区鸟类特有种丰富度较低,但在青海东南部、四川中部和西北部、甘肃南部等地区的丰富度较高;在93°E~121°E或26°N~39°N范围内鸟类特有种丰富度较高. 我国鸟类特有种分布受气候因素限制,年均气温过高或过低、年降水量过高或过低、过于干燥、辐照日数过长或过短等都将使鸟类特有种减少. 鸟类特有种的适宜气候可分为低温干燥、较高温湿度、高温高湿和中等温湿度等类型,但以低温干燥和中等温湿度型为主. 鸟类特有种丰富度与各气候要素相关系数较低,气候要素下丰富度变化呈抛物线型趋势,其中在年均气温为1~18 ℃,年降水量为500~1 300 mm的范围内丰富度较高.      

城市化对上海市五角场地区鸟类群落的影响

从时间及空间2个尺度上分析了城市化对上海市五角场地区鸟类群落的影响。结果表明，城市化过程中五角场地区的鸟类急剧减少，种类数从128种降至46种，科的数目也减少近半，其原因主要是城市化导致鸟类栖息地丧失和栖息环境的改变。农田水网生境的消失直接导致游禽在该区域的全部消失，80%游禽和农田村居鸟类也随之迁出该区域。现存的鸟类群落组成以林区鸟为主，其次是灌丛鸟，主要分布在公园，学校等有大片绿地的区域，其组成特点与现有的园林系统植物群落结构直接相关。城郊自然保护地段仍孕育了大量的鸟类，但由于现有的园林绿化系统结构单一，且彼此分离，呈片断化，难以承担向城内输送物种的任务。一个具有复层混交立体且空间上连续的园林绿地系统是维持城区鸟类多亲性的物质基础。     

辽宁滨海(环渤海)湿地鸟类多样性调查与研究

本研究于2019－2020年对辽宁滨海（环渤海）湿地开展了春迁徙季、秋迁徙季、繁殖季和越冬季的鸟类多样性调查,共监测到鸟类150种,隶属于16目38科,其中,留鸟25种,夏侯鸟26种,冬侯鸟26种,旅鸟73种;国家一级保护鸟类11种,国家二级保护鸟类20种。调查显示:调查区内鸟类多样性的季节差异明显,春、秋迁徙季,鸟类种类与数量明显高于其他两季,越冬季鸟类的种类数量均最少,丰富度指数、均匀度指数、多样性指数和优势度指数均最低。空间分布显示,盘锦地区鸟类种类和数量均最多,达到78种,473084只;营口地区调查到的鸟类种类最少,为55种;锦州地区鸟类数量最少,只有57723只。从鸟类多样性对比来看,盘锦地区最高,大连地区最低,各地鸟类群落组成的空间差异较为明显,在一定程度上受到该地区鸟类生境种类数量及面积大小的影响。辽宁滨海（环渤海）湿地作为东亚—澳大利西亚候鸟迁徙带上的关键区域,当前正面临气候变化、人类围垦干扰造成的鸟类栖息地减少等不利情况,建议通过扩大保护范围、实施修复和管理对策措施、强化宣传等手段保护鸟类多样性及其栖息生境,巩固渤海综合治理攻坚战的治理成效。     

Agri-environment schemes and foraging of barn owls Tyto alba

The barn owl Tyto alba has been in decline throughout much of its range largely as a consequence of loss of foraging habitat resulting from agricultural intensification. The recent introduction of agri-environment schemes in the UK has resulted in the reinstatement of substantial areas of rough grassland which may be of benefit to small mammals and their avian predators. In this study mature grasslands provided by agri-environmental schemes (farm woodlands, permanent set-aside, 2 and 6 m field margins) were compared to better understand which hold the greatest prey numbers and how new areas of grassland targeted at barn owl conservation should be created and managed. In all habitats apart from farm woodlands, small mammal numbers were positively associated with taller swards. This study suggests that areas cut every 2 or 3 years supported more individuals and species than areas cut annually, although this trend was only significant for common shrews. With the introduction of the new Environmental Stewardship scheme in 2005, our results suggest that the area of suitable foraging habitat for barn owls is likely to increase.     

Development of plant communities on set-aside in England

A survey of land taken out of production from the early 1990s onwards under the European Union's set-aside policy in England was carried out in 2008, to record plant communities in set-aside of different ages, effects of distance from the field edge, sowing and soil type. Communities were classified using the Countryside Vegetation System (CVS), Ellenberg indicators and Grime CSR strategy. Species richness declined with distance from the field boundary. Annuals declined with age of set-aside. In older set-aside, perennials dominated, 40-50% of species were grasses, and grasses covered over 70% of the area. Sown areas had a higher proportion of grass species and a lower proportion of wind-dispersed species. Perennial forbs increased over time in naturally regenerated swards but decreased on sown swards. Annuals and grasses were more prevalent on light soils, with more bare ground on heavy soils. Most transects fell into CVS aggregate classes ‘tall grassland/herb’ and ‘fertile grassland’. Ellenberg fertility values decreased initially but then stabilised. Competitor scores increased, and ruderal scores declined, with age. In general, the rate of change declined with age. Although few sites had plant communities of significant conservation interest, the value of set-aside is likely to be primarily to maintain botanical diversity in intensively farmed areas, as well as providing food and habitat for fauna.     

安西极旱荒漠国家级自然保护区鸟类资源的消长变化

1988-1989年安西极旱荒漠自然保护区进行了首次全面的综合考察,为了解1988年以来保护区鸟类资源的变化及其原因,2002-2004年又4次调查了该地区鸟类的种类及数量。15年来安西自然保护区的鸟类资源变化明显。鸟类种类新增加31种(其中甘肃新记录3种),但同时减少了36种。国家重点保护鸟类由原来的18种下降到16种。与1988-1989年相比,2002-2004年春季和夏季鸟类数量下降,秋季数量增加;各个季节的优势种的种类和数量都发生明显变化。影响安西自然保护区鸟类资源变化的主要原因是鸟类迁徙和人类活动。     

新疆鸟类和哺乳动物物种丰富度空间异质性及其多尺度效应

基于新疆维吾尔自治区鸟类和哺乳动10km×10km物种空间分布数据及1km×1km土地利用数据,引入NDVI、海拔和地理纬度等辅助数据,分别对物种和土地利用数据进行尺度变换,计算分析了1~10km尺度下的景观指数,并进一步在生态系统层面进行尺度效应研究,以探究表征物种多样性空间异质性的合理尺度.结果表明：新疆总体的景观类型较为丰富,北疆的景观丰富度和破碎度都相对高于南疆,并且各类型斑块分布不均匀,景观中存在具有优势度的斑块.鸟类在聚落、水体和湿地生态系统中的尺度效应明显,而哺乳动物的尺度效应在农田、森林生态系统比较显著.7~10km尺度下,聚落景观面积越小,分割度越高,水体景观越破碎,越离散,形状越复杂,鸟类丰富度越高.农田和森林生态系统的景观特征对哺乳动物丰富度具有较高的参考价值.7~10km下,农田斑块越离散、形状越复杂,哺乳动物物种丰富度越低;4km尺度下,森林景观斑块形状越复杂、连接度越高,哺乳动物物种越丰富.     

Community richness and stability in agricultural landscapes: The importance of surrounding habitats

In this paper, the role played by habitat diversity in the landscape on species richness and on the stability of farmland bird communities was investigated. Species richness was estimated on 374 samples monitored in farmland by the French breeding bird survey during the 2001–2005 period. A capture–recapture approach was used to estimate species richness accounting for the variation in detection probability among species of the 100 most common species detected in farmland. Landscape structure and composition were measured both in farmland and in adjacent habitats. The independent effect of each variable on community richness and stability was further assessed using hierarchical variance partitioning and taking spatial autocorrelation into account. A strong matrix effect was detected: non-cropped land deeply influenced richness and stability of bird assemblages.     

Potential effects of climate change on birds of the Northeast

We used three approaches to assess potential effects of climate change on birds of the Northeast. First, we created distribution and abundance models for common bird species using climate, elevation, and tree species variables and modeled how bird distributions might change as habitats shift. Second, we assessed potential effects on high-elevation birds, especially Bicknell’s thrush (Catharus bicknelli), that may be particularly vulnerable to climate change, by using statistical associations between climate, spruce-fir forest vegetation and bird survey data. Last, we complemented these projections with an assessment of how habitat quality of a migratory songbird, the black-throated blue warbler (Dendroica caerulescens) might be affected by climate change. Large changes in bird communities of the Northeast are likely to result from climate change, and these changes will be most dramatic under a scenario of continued high emissions. Indeed, high-elevation bird species may currently be at the threshold of critical change with as little as 1°C warming reducing suitable habitat by more than half. Species at mid elevations are likely to experience declines in habitat quality that could affect demography. Although not all species will be affected adversely, some of the Northeast’s iconic species, such as common loon and black-capped chickadee, and some of its most abundant species, including several neotropical migrants, are projected to decline significantly in abundance under all climate change scenarios. No clear mitigation strategies are apparent, as shifts in species’ abundances and ranges will occur across all habitat types and for species with widely differing ecologies.     

Impact of seed mixture and mowing on food abundance for farmland birds in set-asides

We studied the impact of seed mixtures (grass-clover, less competitive grass vs. meadow plant mixture) and mowing (annual mowing vs. no mowing) on the abundance of seed and insect food for farmland birds in set-aside in a long-term field experiment. In general, seed food was less affected by the treatments than insect food. The impact of seed mixture on the abundance of seed food was dependent on the study year: the highest level recorded in the first year, followed by a substantial decline in the following years. Mowing increased the biomass of seed food. The impact of treatments on insect food abundance differed between the total amount of insect food, and had significant interactions with year. Different insect groups dominated in each year as well as their response to the treatments. For the total amount, the meadow plant seed mixture appeared to be the most beneficial and a slight positive impact of mowing appeared in the last two years of the experiment. The results suggest that the value of set-asides in providing food differs according to food components and declines with increasing age of the set-aside.     

Roost type influences torpor use by Australian owlet-nightjars

Australian owlet-nightjars (Aegotheles cristatus; ～50?g) are one of only a few avian species that roost in cavities year-round and regularly enter torpor. Cavity roosts act as thermal buffers, and roost type likely affects energy expenditure of small birds. We used radiotelemetry to locate diurnal winter roost sites of owlet-nightjars in central Australia and to measure body (T (b)) and skin (T (skin)) temperature. We also recorded ambient temperature inside (T (IN)) and outside roosts. Individual owlet-nightjars used one to seven different roosts (tracking time 3-10?weeks), selecting either rock crevices (four birds) or tree hollows (four birds), or switching between the two roost types (seven birds). Rock crevices (T (IN) +9°C to +33°C) were warmer and thermally more stable than tree hollows (T (IN) -4.0°C to +37°C). Torpor, often expressed by a reduction of T (skin)/T (b) by >10°C for 3-4?h at dawn, was influenced by roost selection; torpor use in tree hollows was almost twice that in rock crevices. Despite the potential energy savings accrued from roosting in well-insulated cavities, owlet-nightjars roosted in tree hollows more often (65% bird days, n?=?398) than in rock crevices (35% bird days, n?=?211). Lower costs of arousal from torpor via passive rewarming and basking and decreased risk of predation are two possible explanations for the preference to roost in tree hollows. We provide the first evidence for the influence of cavity roost selection on torpor use in a free-ranging bird and show that roost selection and thermal biology are strongly interrelated in determining energy expenditure.     

Patterns of bird abundance along the agricultural gradient of the Pampean region

Bird and land-use surveys were conducted along the agricultural gradient covering from pure croplands through mixed-farming to pure pastoral-farming scenario in the Pampean region of Argentina. Simple regression analyses were performed to analyse the responses of bird abundance to the percentage of land devoted to crop-production. The specific variables associated to bird abundance within both the crop and pastoral-farming landscapes were identified by running redundancy analyses (RDA). The abundance of 20 out of 43 species (47%) was significantly related to the percentage of cropland, finding negative (65%), positive (25%) unimodal (5%) and bimodal (5%) responses of birds to increasing intensity of crop production. The results showed three types of negative and two types of positive responses of bird abundance to the agricultural gradient. RDA revealed the importance of crop-field types in the crop-production scenario and of cattle presence and grass height in the pastoral-farming scenario for the structuring of the grassland bird community. As most species were negatively affected by crop production, the current land-use homogenisation towards high-intensity croplands will most likely result in population decline of many birds in the region.