盐城滨海海堤林中黑尾蜡嘴雀和黑卷尾的巢址选择与生态位

繁殖期鸟类的巢址选择受到很多因素的影响。许多雀形目鸟类选择在树上营巢,但开阔的沿海地区通常缺乏成片的自然林地,人工种植的廊道状海堤林则成为多种雀形目鸟类的营巢地。2018年4—8月在江苏省大丰麋鹿国家级自然保护区境内的海堤林中,对繁殖鸟类巢的分布及两种优势繁殖鸟类———黑尾蜡嘴雀(Eophona migratoria)和黑卷尾(Dicrurus macrocercus)的巢址选择进行了研究,分析了两种鸟类的生态位重叠情况。结果表明:海堤林生境中共发现10种繁殖鸟的127个巢,鸟巢多数位于5 m以上的空间;影响黑尾蜡嘴雀巢址选择的主要因素是巢树和灌木等,巢位置、乔木和安全等因素是次要因素(前5主分量累计贡献率为71.9%);影响黑卷尾巢址选择的主要是巢树因素和灌木因素,巢向、乔木因子是次要因素(前5主分量累计贡献率78.0%);在巢址生态位分化上:两种鸟类的巢向(U_(test),Z=-3.013,P0.01)、巢高(U_(test),Z=-6.718,P0.01)、巢位置(U_(test),Z=-5.402,P0.01)、隐蔽性(U_(test),Z=-4.081,P0.01)选择上存在极显著的差异,两者在这些因子存在生态位分化;两种鸟类在12个巢址因子选择上的生态位重叠值都较大(最小值为0.500,最大值为0.998),存在激烈的种间竞争;在滨海地区,海堤林是依赖树木筑巢繁殖鸟类的重要栖息地,需要加强保护与管理。     

盐城滨海海堤林中黑尾蜡嘴雀和黑卷尾的巢址选择与生态位

繁殖期鸟类的巢址选择受到很多因素的影响。许多雀形目鸟类选择在树上营巢,但开阔的沿海地区通常缺乏成片的自然林地,人工种植的廊道状海堤林则成为多种雀形目鸟类的营巢地。2018年4-8月在江苏省大丰麋鹿国家级自然保护区境内的海堤林中,对繁殖鸟类巢的分布及两种优势繁殖鸟类---黑尾蜡嘴雀(Eophona migratoria)和黑卷尾(Dicrurus macrocercus)的巢址选择进行了研究,分析了两种鸟类的生态位重叠情况。结果表明:海堤林生境中共发现10种繁殖鸟的127个巢,鸟巢多数位于5 m以上的空间;影响黑尾蜡嘴雀巢址选择的主要因素是巢树和灌木等,巢位置、乔木和安全等因素是次要因素(前5主分量累计贡献率为71.9%);影响黑卷尾巢址选择的主要是巢树因素和灌木因素,巢向、乔木因子是次要因素(前5主分量累计贡献率78.0%);在巢址生态位分化上:两种鸟类的巢向(Utest,Z=-3.013,P<0.01)、巢高(Utest,Z=-6.718,P<0.01)、巢位置(Utest,Z=-5.402,P<0.01)、隐蔽性(Utest,Z=-4.081,P<0.01)选择上存在极显著的差异,两者在这些因子存在生态位分化;两种鸟类在12个巢址因子选择上的生态位重叠值都较大(最小值为0.500,最大值为0.998),存在激烈的种间竞争;在滨海地区,海堤林是依赖树木筑巢繁殖鸟类的重要栖息地,需要加强保护与管理。     

甘肃盐池湾斑头雁巢址选择

2019年4至6月,采用定点观察法和样方法研究甘肃盐池湾国家级自然保护区斑头雁(Anser indicus)巢址选择。研究期间共发现斑头雁巢332个,斑头雁在繁殖期有3种营巢生境,即浅水沼泽、湖心小岛以及山崖,其巢址类型有草垛巢、地面巢和山崖裸岩巢3种。浅水沼泽、湖心小岛以及山崖3种营巢生境中窝卵数分别为(4.7±2.7)枚(n=204)、(4.2±1.9)枚(n=108)及(3.1±0.6)枚(n=20),孵化成功率分别为48.65%(n=199)、45.27%(n=148)及24.00%(n=25),繁殖成功率分别为66.67%(n=42)、74.28%(n=35)及36.36%(n=11)。主成分分析显示,影响浅水沼泽生境中斑头雁巢址选择的主要环境因素依次为水源因素、隐蔽因素、干扰因素和食物因素;影响湖心小岛生境中斑头雁巢址选择的主要环境因素依次为隐蔽因素、食物因素、干扰因素;影响山崖生境中斑头雁巢址选择的主要环境因素依次为地形因素、食物及水源因素、干扰因素。本研究表明,斑头雁在不同营巢生境中,巢址选择的最主要环境因素并不相同,主要依赖生境特征及周围环境因素特征。     

陕西红碱淖同域分布遗鸥与棕头鸥巢址选择比较

2009—2011年4—7月在陕西红碱淖对同域分布的遗鸥和棕头鸥巢参数特征、巢群空间分布和巢址生境选择进行了对比分析。结果表明:巢外径、巢深、巢高等参数均存在显著差异,这主要是与营巢生境和巢址空间分布上有关;从巢群空间分布上来看,两者均选择于湖心岛上营巢繁殖,巢群呈斑块状分布,但彼此没有混巢现象,有时甚至通过压缩种间巢间距来达到共存,由于遗鸥繁殖群体数量占优势,遗鸥总是占据最佳的巢域,棕头鸥巢群通常被排挤至湖心岛边缘部分;在巢址生境选择上,植被类型、植被高度、植被盖度、巢离水面高度和巢距最近水边距离均存在显著差异。这表明两者巢址生境选择上具有特异性,这种特异性使得巢址生境选择上存在生态位差异,促成了遗鸥和棕头鸥能在同一湖心岛上营巢繁殖因素之一。     

荒漠伯劳巢址选择和繁殖成功

2011年5～7月对甘肃安西极旱荒漠国家级自然保护区(N40°21'～40°22',E96°13'～96°14',海拔1 306 m)荒漠伯劳(Lanius isabellinus)巢址选择和繁殖成功进行研究。调查了58巢的巢址因子,巢主要位于营巢树主枝上,巢距地面高度多为2.0～2.5 m。主成分分析结果表明,巢距地面高度、营巢树高度、营巢树胸径和营巢处树干直径是影响荒漠伯劳巢址选择的主要因素,这也是荒漠伯劳适应繁殖地大风天气的结果。既调查巢址数据又明确繁殖情况的49个巢中,红柳(Tamarix ramosissima)(5棵)上巢的繁殖成功率明显高于沙枣(Elaeagnus angusifolia)(43棵)和胡杨(Populus euphratica)(1棵)上的巢,原因可能是红柳郁闭度大。已知窝卵数和繁殖情况的30个巢中,窝卵数分别为2(1巢)、4(7巢)、5(18巢)、6(4巢)。卡方检验结果表明,窝卵数和繁殖成功率之间差异不显著(χ2=3.921,df=3,P0.05)。发现的63个巢中跟踪监测了54个巢(包括调查巢址数据的和未调查巢址数据的)的繁殖情况,54巢中37巢繁殖成功,成功率为68.52%。所有繁殖失败的巢均为产卵阶段或育雏早期阶段由于同类的破坏而导致繁殖失败,繁殖失败巢的数量随着相邻最近巢的距离的增加而减少,因而,繁殖失败可能与种群密度以及种内竞争有关。     

陇东地区金翅雀的巢址选择

为探究金翅雀(Chloris sinica)营巢是否偏好某些树种以及偏好原因,于2017—2019年4—8月,在陇东学院校园内,开展了金翅雀巢址选择调查。180个金翅雀巢址分析显示:金翅雀营巢利用圆柏(Juniperus chinensis)、刺柏(Juniperus formosana)、侧柏(Platycladus orientalis)、日本晚樱(Cerasus serrulata)等17种乔木,其中圆柏(χ2=13.6,df=1,P=0.000)和刺柏(χ2=9.8,df=1,P=0.002)是金翅雀选择的主要树种;与其他巢址比较,圆柏和刺柏巢址的巢树树冠直径(DNTC)、巢-缘距(DEC)和巢树-最近树距离(DT)显著小于其他树种巢址的相应参数,而圆柏和刺柏巢址的巢树树冠高度(HNTC)、巢-冠底距离(DBC)、巢树-草地距离(DM)、可利用林木数量(NT)和隐蔽度(CC)都显著大于其他树种巢址的相应参数(T或Mann-Whiteny U检验,全部P0.05);差异显著的8个巢址参数(DNTC、DEC、DT、HNTC、DBC、DM、NT和CC)的因子分析表明,环境隐蔽性、巢位隐蔽性和巢位不易接近性是导致金翅雀偏好在圆柏和刺柏上营巢的主要因素。本研究结果可为城市环境绿化中如何保护鸟类提供参考。     

营巢植物影响红头长尾山雀的巢被捕食风险

巢址选择对鸟类的巢捕食率具有重要影响,研究鸟类的巢址特征与巢捕食率之间的关系有利于揭示不同巢址特征对鸟类成功繁殖的作用。本研究以2014至2017年在河南董寨国家级自然保护区观察的红头长尾山雀(Aegithalos concinnus)为研究对象,分析了红头长尾山雀在卵期(产卵及孵卵期)(n = 124巢)及育雏期(n = 119巢)被捕食巢和成功巢的日存活率与发现巢的时间和营巢植物种类之间的关系,同时还根据其巢址的总体特征对其巢址安全性进行评级,以探究研究者评估的巢址安全等级对预测巢存活率的有效性。结果显示：在卵期,营巢于竹类植物(如箬竹Indocalamus tessellatus和刚竹属Phyllostachys sp.植物)、茶(Camellia sinensis)、灌草类植物(如蔷薇Rosa spp.和禾本科Gramineae植物)和杉木(Cunninghamia lanceolata)上的红头长尾山雀巢的日存活率皆显著高于在松柏类植物(如油松Pinus massoniana、侧柏Platycladus orientalis和圆柏Juniperus chinensis)上的巢;在育雏期,营巢于灌草类植物上巢的日存活率显著低于竹类、杉木和茶树上巢的日存活率。卵期巢的日存活率随巢日龄的增加而显著降低,但育雏期巢的日存活率不随巢日龄显著变化。此外,巢的日存活率与发现巢的日期之间没有显著关系,研究者评估为巢址安全等级不同的巢,其日存活率也无显著差异。综上所述,本研究的结果表明,营巢于某些特定植物有助于降低红头长尾山雀面临的巢捕食风险,说明营巢植物种类对鸟类的繁殖成功率具有重要影响。     

乌鲁木齐市不同生境繁殖期的鸟类群落多样性及功能集团分析

2016—2019年对乌鲁木齐市7种生境(高寒草甸、针叶林-灌丛、草原、农田、荒漠、湿地和城市公园)的繁殖期鸟类进行实地调查。共记录鸟类178种,隶属19目45科,其中雀形目Passeriformes最具代表性,共86种(占48.3%);居留型以夏候鸟和留鸟为主,共153种(占86.0%);分布型以古北型为主,共82种(占46.1%);珍稀濒危和重点保护物种共33种(占18.5%)。鸟类群落物种数及个体数最多的为湿地生境,荒漠、针叶林-灌丛生境次之,各生境物种数(H=30.628,P0.001)存在显著性差异。湿地生境鸟类的Shannon-Wiener多样性指数最高,高寒草甸生境的最低;草原生境的Pielou均匀度指数最高,高寒草甸生境的最低;高寒草甸生境的Simpson优势度指数最高,草原生境的最低;针叶林-灌丛生境的物种丰富度指数最高,荒漠生境的最低。草原与针叶林-灌丛生境之间的Sorensen相似性系数最高(0.59),高寒草甸与荒漠之间的最低(0)。湿地生境鸟类群落的捕食集团以食虫性为主,其他生境以杂食性为主。湿地生境中鸟类营地面巢的居多,高寒草甸生境中鸟类营洞巢的居多,其他生境中鸟类营编织巢的居多。上述结果表明,乌鲁木齐市周围的湿地生境应该得到优先保护。     

东北地区北红尾鸲巢址选择及繁殖成效

北红尾鸲(Phoenicurus auroreus)是一种分布广泛的小型雀形目鸟类,主要分布于南亚东北部,东南亚北部、东亚及俄罗斯等地区,我国东北、华北、华中至西南等地也均有分布,是重要的食虫益鸟。为探究北红尾鸲巢址选择的影响因素,找到影响北红尾鸲繁殖成功率的主要巢址因子,于2017年4—7月,在辽宁仙人洞国家级自然保护区开展系统研究。共发现北红尾鸲自然巢44个,其中29巢繁殖成功,15巢繁殖失败。北红尾鸲主要筑巢于石墙缝、空心砖墙缝及废旧电表箱中。巢址参数的主成分分析结果表明:巢口因子(27.738%)、巢位因子(14.195%)、光照因子(12.145%)、人为干扰因子(10.440%)、安全因子(9.266%)和隐蔽因子(7.187%)是影响北红尾鸲巢址选择的重要因子。采用二元逻辑斯蒂回归分析繁殖成功巢与失败巢参数发现,成功巢的巢口最大高度显著小于失败巢(P=0.047),且其距顶的距离更近(P=0.043)。多元线性回归分析表明,巢上方盖度对繁殖成功率有极显著影响(t=2.883,P=0.009)。总的来说,北红尾鸲虽偏爱筑巢于人为干扰较大的村庄房屋附近,但较小的巢口能有效避免巢捕食者的捕食,更近的距顶距离和更大的巢上方盖度能有效降低巢上方的可视程度和降水等不利因素的影响,从而提高繁殖成功率。     

青藏高原胡兀鹫与巢域中峭壁生境营巢鸟类的种间互动关系初探

胡兀鹫(Gypaetus barbatus)是峭壁生境营巢鸟类,其领域是关系到繁殖与生存的必需资源。2010~2013年,在青藏高原4个省区中的7个胡兀鹫繁殖地进行了调查,结合1990~1993年的调查资料,用直接观察法记录了12个胡兀鹫繁殖巢域(距巢址500 m范围内)中的峭壁生境营巢繁殖鸟类,并初步评估了这些鸟类与胡兀鹫的种间关系。结果表明,巢区中观察到其体型可引起胡兀鹫警觉反应的鸟类计有23种,营巢繁殖的有11种。繁殖鸟类中猛禽有高山兀鹫(Gyps himalayensis)、猎隼(Felco cherrug)、金雕(Aquila chrysaetos)、大鵟(Buteo hemilasius)、长耳鸮(Asio otus)5种,鸦科鸟类有红嘴山鸦(Pyrrhocorax pyrrhocorax)、黄嘴山鸦(P.graculus)和大嘴乌鸦(Corvus macrorhynchos)3种。前述23种可引起胡兀鹫警觉反应的鸟类在胡兀鹫巢域中被记录到的活动行为频次为1 298次·只,观察到12种鸟与胡兀鹫发生种间互动行为,频次合计65次,其中鸦科鸟类与胡兀鹫发生的种间互动行为频次最高(34次)。观察到胡兀鹫驱赶巢域内的捕猎金雕导致其放弃猎物的行为。对种间关系的初步评估结论为:(1)毗邻高山兀鹫繁殖巢的胡兀鹫,表现出同种繁殖对之间巢间距明显缩短的现象,其巢间距由35.84 km(25.10~47.30 km,n=6个巢)缩短至7.39 km(6.22~8.58 km,n=5个巢);(2)在胡兀鹫巢域中营巢繁殖的猎隼,其同种间巢间距缩短至150~360 m(n=4个巢);(3)由于高山兀鹫在当地传统文化习俗中的重要地位,胡兀鹫与其毗邻营巢,可以在很大程度上降低人类直接干扰活动对其繁殖成功率的不利影响;(4)在人为干扰活动或其他原因导致胡兀鹫亲鸟离巢的情况下,鸦科鸟类和捕食性猛禽(尤其是猎隼)的存在,在很大程度上增加了胡兀鹫卵和幼雏被天敌掠食的可能性;(5)胡兀鹫育雏早期需要获取肉含量高的食物(体型较小的死亡动物),在胡兀鹫巢域或附近区域营巢的捕食性猛禽所遗落的猎物,很可能具有一定程度的补充作用。     

甘肃盐池湾黑颈鹤筑巢栖息地偏好及人为干扰的影响

作为高原旗舰物种, 黑颈鹤(Grus nigricolli)是反映高原生态健康状况的重要参考。为了解黑颈鹤如何在多因素作用下适应人类改造过的栖息地环境, 本研究利用遥感解译、最近邻分析与随机森林模型对繁殖于甘肃盐池湾国家级自然保护区党河湿地的黑颈鹤的筑巢栖息地偏好及人为干扰进行研究。2019年和2020年每年的4-9月在党河湿地内对巢位点等数据进行收集。研究结果表明: 党河湿地内巢址与人为干扰的分布位置明显不同, 两者的主要分布区呈现镶嵌状。距深水沼泽距离、距浅水沼泽距离与距湖泊距离是影响黑颈鹤筑巢栖息地选择最关键的3个环境因子。黑颈鹤筑巢时偏好在距离深水沼泽< 125 m、距离浅水沼泽< 130 m、距离湖泊< 270 m的区域内筑巢。黑颈鹤对沼泽、湖泊等资源的偏好是其巢址分布格局的主要驱动力, 而房屋与公路等人为干扰对栖息地选择的影响很小。黑颈鹤筑巢时强烈偏好的栖息地在湿地内占比低、分布聚集且适宜范围有限, 繁殖区域较狭窄。黑颈鹤巢址间距离的上升表明黑颈鹤栖息地质量可能有所下降, 牲畜数量的增长、冬季牧场的多季节利用以及气候变化可能是主要原因。建议在党河湿地内不新增房屋及公路等人为干扰, 同时继续适当限牧, 并给予牧民充足的经济补偿。     

Constructed Wetland Habitat for American Avocet and Black-Necked Stilt Foraging and Nesting

Abstract In 1994, a 117-ha wetland was designed, constructed, and operated by the Tulare Lake Drainage District (TLDD), California, USA, to provide foraging and nesting habitat for American avocets (Recurvirostra americana) and black-necked stilts (Himantopus mexicanus). The wetland was operated seasonally in compliance with regulatory requirements to compensate for impacts to stilts, avocets, and other wildlife exposed to elevated selenium concentrations, fluctuating water levels resulting in nest flooding, and high nest-predation rates at the TLDD agricultural drainage evaporation basins. Water supply for the wetland was from low-selenium (typically <2 μg/L) saline agricultural drainage water, although the facility also had capability to blend and use freshwater and saline supplies. Coincident with wetland construction, 2 evaporation basins totaling 1,174 ha were physically modified and operated to discourage their use by shorebirds. In the first year of wetland operation (1995), American avocet and black-necked stilt nest construction at the wetland was 17.6 nests/ha. This compares to a preproject (1994) combined density of 1.9 nests/ha at the evaporation basins. From 1995 through 2004, annual nesting attempts by American avocets and black-necked stilts at the wetland averaged 2,896 per year (24.8 nests/ha). American avocets and black-necked stilts represented 91% of the nests observed at the wetland. Over the 10-year monitoring period, nest success at the wetland averaged 82% for American avocets and 75% for black-necked stilts. We estimated nest predation rates at the constructed wetland to be <1%. During the same period, American avocet and black-necked stilt nesting at the evaporation basins declined from 2,266 in 1994 to 9 in 2004. The constructed wetland has proven to be effective in attracting and providing suitable nesting habitat for large numbers of avocets and stilts. Results of this long-term study confirm the validity of management recommendations for American avocets and black-necked stilts and suggest that agricultural drainage can be successfully managed to provide highly productive managed wetlands.     

景观基质对雅江中游河谷黑颈鹤冬季觅食地选择的影响

生态系统中生境斑块并非孤立存在，而是嵌于周边景观基质中。生境内种群赖以生存的资源和环境条件不仅取决于生境本身，更与景观基质组成与结构紧密关联。黑颈鹤是青藏高原的旗舰物种，雅鲁藏布江中游河谷高寒湿地是全球最大的黑颈鹤越冬地，为其提供了良好的觅食生境。厘清该区域黑颈鹤觅食生境选择如何受景观基质组成结构的影响，对于青藏高原旗舰物种保护以及流域生态系统综合治理具有重要意义。运用景观生态学原理，以遥感影像和实地黑颈鹤种群调查数据为基础，结合景观基质多尺度缓冲区构建、相关分析以及Maxent模型，分析2000-2020年雅江中游河谷黑颈鹤国家级自然保护区（日喀则片区）景观格局时空变化和觅食地生境特征及其与黑颈鹤种群的关系，探究景观基质对黑颈鹤觅食地选择的影响，并利用关键生境因子模拟黑颈鹤生境适宜性分布。通过分析发现：（1）时间尺度上，雅江中游河谷耕地面积先增加后下降，滩地持续减少；空间尺度上，觅食黑颈鹤种群呈东多西少的集群分布特征，其分布范围与河谷内耕地分布基本吻合；（2）景观基质对黑颈鹤觅食地选择影响显著。景观结构上，黑颈鹤偏好连通性好、优势度高的景观基质；景观组成上，偏好基质中耕地和水域类型，这与黑颈鹤的觅食习性及对环境安全的生态位需求有关；（3）景观基质结构组成对黑颈鹤觅食地选择的影响具有显著的尺度效应。景观基质结构影响最显著的空间尺度为1500-2000m。但基质中耕地、草地和水域等景观组成要素对黑颈鹤的影响具有不同空间尺度效应，分别为1500m、3000m和4000m；（4）通过模型模拟，揭示出黑颈鹤适宜生境面积先增后减，但总体较2000年呈上升趋势，且基质中觅食地与耕地的距离、水域斑块密度和偏好景观组成的优势度始终是生境适宜性解释率最高的景观因子。本研究揭示出，该区域乡村规划应该统筹优化黑颈鹤栖息生境及其景观基质中的作物生产以及居民生活，形成以黑颈鹤旗舰物种保护为核心的高寒湿地生态系统综合管理模式，从而增强青藏高原高寒生态系统的稳定性和可持续性，同时也为深入研究物种生境选择机制提供了思路。     

SHOREBIRD HABITAT USE AND NEST-SITE SELECTION IN THE PLAYA LAKES REGION

Abstract: Wetlands in the Playa Lakes Region (PLR) provide important habitats for wintering waterfowl, cranes, and both migrant and breeding shorebirds. Playa Lakes Region wetlands experience naturally fluctuating hydroperiods but are exposed to anthropogenic stresses, which are exacerbated during summer and may influence PLR wetland occupancy and selection by breeding shorebirds. We examined wetland-scale habitat use and nest-site selection of the 4 dominant shorebirds (American avocets [Recurvirostra americana], black-necked stilts [Himantopus mexicanus], killdeer [Charadrius vociferus], snowy plovers [C. alexandrinus]) nesting in playas, saline lakes, and in both created and riparian wetlands in the PLR of Texas, USA. All 4 species nested in saline lakes. Only avocets and killdeer nested in playas, and snowy plovers nested in riparian wetlands. No nests were found in created wetlands. Wetland habitat changed (P < 0.001) during the breeding season, while water habitats generally decreased. Used (i.e., shorebirds found nesting) wetlands had more (P < 0.05) mudflats than non-used (i.e., shorebirds not found nesting) wetlands, which had more (P < 0.05) dry habitats. Used and non-used wetlands had similar (P > 0.05) amounts of water habitats. Nests were located close to vegetation on bare dry ground and dry ground with vegetation. Because water is ephemeral in PLR wetlands, shorebirds must select—in a somewhat predictive manner upon arrival—wetlands with suitable nest-site and brood-rearing habitat. Although surface water is necessary for nesting, its presence is not adequate for delineating suitable PLR wetland habitat for breeding shorebirds. Our findings that created wetlands cannot compensate for regional wetland losses in habitat or function highlights the need for conservation of natural PLR wetlands     

Habitat edges affect patterns of artificial nest predation along a wetland-meadow boundary

Wetland habitats are among the most endangered ecosystems in the world. However, little is known about factors affecting the nesting success of birds in pristine grass-dominated wetlands. During three breeding periods we conducted an experiment with artificial ground nests to test two basic mechanisms (the matrix and ecotonal effects) that may result in edge effects on nest predation in grass-dominated wetland habitats. Whereas the matrix effect model supposes that predator penetrate from habitat of higher predator density to habitat of lower predator density, thus causing an edge effect in the latter, according to the ecotonal effect model predators preferentially use edge habitats over habitat interiors. In addition, we tested the edge effect in a wetland habitat using artificial shrub nests that simulated the real nests of small open-cup nesting passerines. In our study area, the lowest predation rates on ground nests were found in wetland interiors and were substantially higher along the edges of both wetland and meadow habitat. However, predation was not significantly different between meadow and wetland interiors, indicating that both mechanisms can be responsible for the edge effect in wetland edges. An increased predation rate along wetland edges was also observed for shrub nests, and resembled the predation pattern of real shrub nests in the same study area. Though we are not able to distinguish between the two mechanisms of the edge effect found, our results demonstrate that species nesting in wetland edges bordering arable land may be exposed to higher predation. Therefore, an increase in the size of wetland patches that would lead to a reduced proportion of edge areas might be a suitable management practice to protect wetland bird species in cultural European landscapes.     

基于多源遥感的贵州草海国家级自然保护区黑颈鹤生境适宜性评价

生境适宜性评价是保护和管理濒危物种的重要途径。已有研究中用于物种生境适宜性评价的环境变量数据多存在分辨率低精度不高的问题,在研究小尺度物种生境适宜性时误差较大。为解决这一问题,本文根据黑颈鹤的出现点数据与光学、雷达遥感数据及地形辅助数据得出栖息地与觅食地特征,利用最大熵(MaxEnt)模型对草海越冬黑颈鹤细尺度的生境适宜性进行评价。结果显示：(1)运用多源遥感和地形辅助数据生成的环境变量结合MaxEnt预测黑颈鹤的栖息地与觅食地效果都较为优秀,两者受使用者工作特征曲线下的面积值(AUC)值均大于0.94;(2)距耕地距离、距水域距离、水深及距建筑距离是影响黑颈鹤栖息地主要环境因子,而影响觅食地分布的主要环境因子则是距耕地距离、优势植被、距建筑物距离和水深。(3)草海自然保护区黑颈鹤栖息地与觅食地的最适宜区和次适宜区面积较小,栖息地与觅食地最、次适宜区总和分别为6.404km~2与12.644 km~2,占比仅为研究区的6.43%和12.69%。通过调查发现,当前自然保护区的人为干扰源主要是游客和当地的居民,潜在地威胁着黑颈鹤的栖息地和觅食地。因此,为了避免保护区黑颈鹤栖息地与觅食地的退...     

生境破碎化对丹顶鹤巢位选择的影响

1985、1995年和1998年4－5月,采用查阅保护区历史资料及实地调查方法,对辽宁双台河口国家级自然保护区内丹顶鹤（Grus japonensis)的主要营巢地－东郭苇场和赵圈河苇场的生境破碎化及丹顶鹤在2片苇场中的营巢状况和繁殖种群数量变动情况作了系统的考察和研究,发现丹顶鹤的营巢生境破碎严重,已由成片的芦苇湿地变成91个斑块,其中最小营巢斑块面积为0．37km^2,最小巢间距为304m,比过去资料记载的最小巢区面积缩小了0．72km^2,但繁殖种群数量变动不大,多年来一直维持在30对左右,丹顶鹤为了适应变化了的环境,已采取了缩小巢区面积的生态适应对策。     

Nest Site Selection by Greater Sage-Grouse in Mono County,California

ABSTRACT Loss of nesting habitat is believed to be a factor in the decline of greater sage-grouse (Centrocercus urophasianus) throughout its range. Few data are available for sage-grouse in Mono County, California, USA, in the most southwestern portion of the species’ range. We studied habitat selection of nesting sage-grouse in Mono County, California, from 2003 to 2005 by capturing and radiotracking females to identify nesting locations. We sampled vegetation at nest sites and randomly selected sites within 200 m of nests and within each of 5 subareas within Mono County. Nest sites were characterized by 42.4 ± 1.3% (x̄ ± SE) shrub canopy cover, 10.5 ± 1.0 cm residual grass height, and 2.7 ± 1.0% residual grass cover. Shrub cover was the only variable found to differentiate nest sites from randomly selected sites. Unlike some other studies, we did not find understory vegetation to be important for selecting nest sites. Mean shrub cover was 38.7 ± 1.5% at random sites within 200 m of nests and 33.6 ± 1.6% at random sites at the approximate scale of home ranges, indicating that nesting females selected nesting areas that contained denser shrubs than their home range, and nest sites that contained greater shrub cover than the vicinity immediately surrounding nests. Our results suggest that managers should consider managing for greater shrub cover in Mono County than what is currently called for in other parts of sage-grouse range and that management for sage-grouse habitat may need to be tied more closely to local conditions.     

Survival rates, causes of failure and productivity of Skylark Alauda arvensis nests on lowland farmland

This paper analyses data from 995 Skylark Alauda arvensis nests found on lowland farms in southern England from 1996 to 1998. The majority of recorded nest failures were caused by predation except in agricultural grass, where trampling and agricultural operations were equally important. Nest survival rates varied between crop types, nests in cereals being around twice as likely to succeed as nests in grass or set-aside. In cereals, nest survival rates increased with increasing distance from the nearest tramline and declined over the course of the breeding season. Predator control also had a significant independent effect on nest survival rates. On one farm where many other factors were held constant, a highly significant increase in nest survival rates from 12.3% to 40.7% coincided with the introduction of intensive predator control, which also appeared to bring forward mean laying dates. Most environmental factors explaining significant variation in nest survival rates did so only at the chick stage. The mean number of chicks produced per nesting attempt was 1.26 in cereals, 0.78 in set-aside and 0.63 in grass, the differences being due primarily to variation in nest survival rates. Low densities of Skylark territories in cereal crops are not therefore the consequence of low breeding success at the scale of the individual nest and probably reflect limitations on the number of attempts made in a season. Measures taken to improve the attractiveness of cereal crops as a nesting habitat for Skylarks, and beneficial changes in grassland management, are likely to increase overall productivity.     

Nesting biology of Black-shouldered Kite (Elanus caeruleus) in oil palm landscape in Carey Island,Peninsular Malaysia

Black-shouldered Kite (Elanus caeruleus) is a well-known raptor that inhabits open areas such as oil palm plantation or paddy field. To determine preferable habitat and nesting site of Black-shouldered Kite in oil palm landscape, we conducted a study on Black-shouldered Kite’s nesting biology in Carey Island, Selangor, Malaysia. We divided the island into six types of habitat and conducted road-side count of Black-shouldered Kite from April 2009 to February 2011. Whenever the Black-shouldered Kite was detected, we thoroughly searched the surrounding area for their nest. In total, we have recorded forty nests. The nests were built on 15 species of trees but most of the trees shared common physical characteristics. Some novice breeders also used oil palm tree as their nesting site. Structure and building materials of nests constructed on oil palm trees were different from nests built on other trees. Of all breeding attempts, only four nests which were located in residential area adjacent to young oil palm habitat were successful. Among important characteristics of successful nesting site include taller trees with strong branches and good leaf coverage. These trees not only protect nests from predator detection (except from other predatory birds) and physical environment but also facilitate Black-shouldered Kite’s foraging activities by providing good vantage point.