骨顶鸡日行为活动对游憩干扰的反应

近年来,湿地生态旅游在我国各地逐渐兴起,水鸟作为湿地生态系统的重要成分,其行为是否因游憩活动而改变成为了重要的研究内容。本文以黑龙江省安邦河自然保护区为研究区,调查了骨顶鸡(Fulica atra)对湿地游憩活动的行为反应,用瞬时扫描取样法分别观察了码头区、游船区和对照区骨顶鸡成鸟及幼鸟的日行为活动。结果表明,码头区成鸟比对照区取食时间显著减少,隐藏的时间明显增加,游走和整理活动显著降低;游船区成鸟比对照区出现更多的攻击和隐藏行为。游憩区幼鸟与对照区的取食、隐藏和躲避时间有显著差异。游憩干扰还表现在码头区成鸟的取食节律片段化,成鸟和幼鸟隐藏频率较高的时段与游人的活动高峰相一致。研究认为,游船区干扰对骨顶鸡的影响较码头区小,幼鸟比成鸟对干扰的适应能力更强。由于高强度的游憩干扰对骨顶鸡等水鸟种群秋迁前的能量蓄积不利,因此建议增加码头路边隔离绿化带,在游船与骨顶鸡领域间设置浮标隔离带,加强对游憩活动的管理。     

卧龙血雉繁殖期行为特征分析

1 995年 4～ 6月在四川卧龙自然保护区五一棚地区 ,采用无线电追踪技术结合野外行为观察 ,对血雉繁殖期行为特征进行了研究。结果表明 ,繁殖前期雄鸟在警戒行为的频次及持续时间上均显著地高于雌鸟 (T test,频次 ,t=-4 73 ,P <0 0 1 ;时间 ,t=-2 80 ,P <0 0 5 ) ;孵卵期 ,雄鸟在警戒行为的总持续时间上显著地高于雌鸟 (T test,t=-4 75 ,P <0 0 1 ) ,雌鸟在取食行为的总持续时间上显著地高于雄鸟 (T test,t=3 41 ,P <0 0 5 ) ;对雌雄个体行为同时进行观察的结果表明 ,雌鸟维持行为的时间与雄鸟警戒行为的时间显著正相关 (Y =49 68+0 2 693X ,r=0 71 79,P =0 0 0 2 6)。繁殖前期和孵卵期雄鸟的警戒行为可以提高雌鸟用于取食、理羽、沙浴的时间 ,而减少用于警戒的时间     

大鵟繁殖期的行为及时间分配

2015年4～9月,采用焦点动物取样法,通过人工观察及监控设备记录,在青海省祁连县研究了2窝在人工巢中繁殖的大(鵟)(Buteo hemilasius)行为.构建了大(鵟)亲鸟及雏鸟在繁殖期的行为谱,将亲鸟繁殖期内的行为划分为12项30种,将雏鸟的行为划分为9项25种.研究发现,大(鵟)繁殖期开始于4月中下旬,持续至8月中旬结束,平均(112.0±2.0)d(n=2);将繁殖期划分为孵卵前期、孵卵期、育雏期及雏鸟成熟期.利用单因素方差分析(One-way ANOVA)比对了雌雄亲鸟之间,以及不同时期间亲鸟、雏鸟的行为时间分配.结果显示,(1)雌雄大(鵟)之间的行为时间分配在孵卵前期及孵卵期差异不显著(P＞0.05),在育雏期及雏鸟成熟期差异显著(P＜0.05).在这两个时期,雌性栖停行为所占比例显著高于雄性(P＜0.01),而捕食行为占比显著低于雄性(P＜ 0.01).(2)雌性大(鵟)行为时间分配在不同时期均变化显著(P＜ 0.05),雄性大(鵟)行为时间分配在育雏期与雏鸟成熟期间差异不显著,其余各个时期间差异显著(P＜ 0.05).(3)大(鵟)雏鸟行为时间分配在育雏期与成熟期之间差异显著(P＜0.05).     

大■繁殖期的行为及时间分配

2015年4~9月,采用焦点动物取样法,通过人工观察及监控设备记录,在青海省祁连县研究了2窝在人工巢中繁殖的大■(Buteo hemilasius)行为。构建了大■亲鸟及雏鸟在繁殖期的行为谱,将亲鸟繁殖期内的行为划分为12项30种,将雏鸟的行为划分为9项25种。研究发现,大■繁殖期开始于4月中下旬,持续至8月中旬结束,平均(112.0±2.0)d(n=2);将繁殖期划分为孵卵前期、孵卵期、育雏期及雏鸟成熟期。利用单因素方差分析(One-way ANOVA)比对了雌雄亲鸟之间,以及不同时期间亲鸟、雏鸟的行为时间分配。结果显示,(1)雌雄大■之间的行为时间分配在孵卵前期及孵卵期差异不显著(P0.05),在育雏期及雏鸟成熟期差异显著(P0.05)。在这两个时期,雌性栖停行为所占比例显著高于雄性(P0.01),而捕食行为占比显著低于雄性(P0.01)。(2)雌性大■行为时间分配在不同时期均变化显著(P0.05),雄性大■行为时间分配在育雏期与雏鸟成熟期间差异不显著,其余各个时期间差异显著(P0.05)。(3)大■雏鸟行为时间分配在育雏期与成熟期之间差异显著(P0.05)。     

旅游区游憩活动对鸟类扩散种子的影响

鸟类在植物种子传播中扮演着重要的角色。为了研究旅游活动对鸟类传播种子的影响,在兴凯湖自然保护区游憩区和非游憩区选择黄檗(Phellodendron amurense Rupr.)树种作为观测对象进行对比研究。结果显示,游人活动高峰时段游憩区鸟的取食行为发生了明显改变,取食鸟的物种丰富度、取食频度、取食时间以及种子取食量均显著减少。观察发现,游人活动干扰是导致鸟的取食行为发生改变的根本原因。取食行为的改变,减少了种子的扩散机会,进一步导致了幼苗更新量的减少以及相对较短的扩散距离。此外,对幼苗更新格局的检验发现,游憩区幼苗在空间分布上明显偏向景观内部。产生该结果的原因与鸟的飞离路径有关,来自景观外部的游人干扰压力可能是导致鸟的飞行路径发生改变的主要原因。结果表明,旅游活动可能通过干扰动植物关系对植物产生连锁影响。     

骨顶鸡等游禽对不同人为干扰的行为响应

分别于2008年4月至6月和2009年4月至6月,采用目标动物取样法在黑龙江省安邦河湿地和大庆龙凤湿地研究了骨顶鸡等水鸟对人为干扰的行为响应.结果表明:骨顶鸡对行人和机动车辆两种干扰的反应距离类似,但耐受程度有所不同,骨顶鸡对机动车辆干扰的耐受性要好于行人干扰.在以游客等行人干扰为主的安邦河湿地,骨顶鸡以及其他游禽对干扰产生行为反应的比例要高于以机动车辆干扰为主的龙凤湿地,说明相对于行人干扰骨顶鸡对机动车辆更容易耐受;在安邦河湿地,骨顶鸡对划船的反应距离以及反应程度要大于人行走,说明骨顶鸡对于侵入性的干扰更为敏感.此外,对凤头鹛鹏(Podicepscristatus)、黑颈鹏鹧(Podiceps nigricollis)、小鹏鹏(Tachybaptus ruficoUis)、黑水鸡(Gallinula chloropus)、红头潜鸭(Aythya ferina)、赤膀鸭(Anas strepera)、绿头鸭(Anas platyrhynchos)、斑嘴鸭(Anas poecilorhyneha)、绿翅鸭(Arias crecca)、白眉鸭(Anasquerquedula)、赤颈鸭(Ariaspenelope)、琵嘴鸭(Anas clypeata)等游禽对人为干扰的反应距离、耐受距离以及遭受干扰时的反应比例进行了研究,结果显示3种鹛鹧对干扰的耐受距离差异不显著,12种鸭类中红头潜鸭对人为干扰的敏感性要小于其他鸭类,斑嘴鸭和绿头鸭则相对敏感.     

若尔盖湿地骨顶鸡的繁殖生态及适应性探讨

本文研究了四川省若尔盖湿地骨顶鸡Fulica atra的繁殖生态,讨论了骨顶鸡繁殖特征对高原的适应性。结果表明:若尔盖骨顶鸡平均筑巢期为6.73 d±0.36 d,平均巢底距水面距离平均为7.83 cm±0.64 cm,未发现对旧巢重复利用的现象;平均窝卵数5.83枚±2.15枚,平均卵质量31.90 g±0.37 g,平均孵卵时间26.64 d±2.83 d。与低海拔平原湿地相比,高寒湿地繁殖的骨顶鸡窝卵数更少、孵化期更长,并偏好在植被盖度适中、紧邻植被且草高较高的生境中营巢。主成分分析结果显示,影响研究区域骨顶鸡巢址选择的主要因子是安全因子,其次是交通因子与种内竞争因子。与平原地区繁殖的骨顶鸡相比,若尔盖地区骨顶鸡在繁殖生态特征上呈现出对安全因子高度偏好的特点,可能是其对高原多变气候环境和较高捕食压力的一种适应和选择策略。     

骨顶鸡等游禽对不同人为干扰方式的响应

分别于2008年4月至6月和2009 年4月至6月, 采用目标动物取样法在黑龙江省安邦河湿地和大庆龙凤湿地研究了骨顶鸡等水鸟对人为干扰的行为响应。结果表明:骨顶鸡对行人和机动车辆两种干扰的反应距离类似,但耐受程度有所不同,骨顶鸡对机动车辆干扰的耐受性要好于行人干扰。在以游客等行人干扰为主的安邦河湿地,骨顶鸡以及其他游禽对干扰产生行为反应的比例要高于以机动车辆干扰为主的龙凤湿地,说明相对于行人干扰骨顶鸡对机动车辆更容易耐受;在安邦河湿地,骨顶鸡对划船的反应距离以及反应程度要大于人行走,说明骨顶鸡对于侵入性的干扰更为敏感。此外,对凤头(Podiceps cristatus)、黒颈(Podiceps nigricollis)、小(Tachybaptus ruficollis)、黑水鸡(Gallinula chloropus)、红头潜鸭(Aythya ferina)、赤膀鸭(Anas strepera)、绿头鸭(Anas platyrhynchos)、斑嘴鸭(Anas poecilorhyncha)、绿翅鸭(Anas crecca)、白眉鸭(Anas querquedula)、赤颈鸭(Anas penelope)、琵嘴鸭(Anas clypeata)等游禽对人为干扰的反应距离、耐受距离以及遭受干扰时的反应比例进行了研究,结果显示3种对干扰的耐受距离差异不显著,12种鸭类中红头潜鸭对人为干扰的敏感性要小于其他鸭类,斑嘴鸭和绿头鸭则相对敏感。     

河南董寨赤腹鹰孵卵节律与巢防卫行为

2016和2017年的5月至8月,在河南省董寨国家级自然保护区利用红外相机监控和野外直接观察赤腹鹰(Accipiter soloensis),对其孵卵节律和巢防卫行为进行了研究。为了更好地获得巢防卫数据,我们以人作为入侵者攀爬巢树,观察人停留在巢树上10 min内不同赤腹鹰个体的巢防卫行为。共发现赤腹鹰繁殖巢52个,累计拍摄红外照片661 306张,将15个繁殖巢内的30只个体的巢防卫行为分成了4个等级。研究表明:1)雄鸟的巢防卫等级与雄鸟的日孵卵次数(r=0.751,n=15,P0.01)、雄鸟日孵卵时间(r=0.803,n=15,P0.01)、每日雌雄孵卵总时间(r=0.527,n=15,P0.05)均呈显著正相关,雌鸟的巢防卫等级与雄鸟的日孵卵次数(r=0.717,n=15,P0.01)、雄鸟的日孵卵时间(r=0.619,n=15,P0.05)呈显著正相关(Sperman rank correlation);2)雌鸟巢防卫强度与雄鸟巢防卫强度呈显著正相关(r=0.743,n=15,P0.01);3)亲鸟的平均离巢时间与雄鸟的日孵卵次数(r=﹣0.680,df=11,P0.05)、雄鸟的日孵卵时间(r=﹣0.640,df=11,P0.05)、雌鸟的孵卵次数(r=﹣0.558,df=11,P0.05)、每日雌雄孵卵总时间(r=﹣0.772,df=11,P0.01)均呈负相关。可见,赤腹鹰的巢防卫强度和孵卵投入密切相关,并且配偶间的巢防卫行为存在相似性,可能与配偶选择和学习行为有关。     

紫水鸡非繁殖期日节律与时间分配

2011年1月至11月使用瞬时扫描法及焦点动物取样法对云南省大理市洱源县西湖湿地(26°00′~26°01′N,100°02′~100°03′E,平均海拔1 970 m)的紫水鸡(Porphyrio porphyrio)行为进行了观察,将行为定义为取食、寻食、休息、修饰、警戒、位移和其他共7类,扫描时将取食和寻食合并为觅食,分析非繁殖期的日节律和时间分配特点。觅食高峰出现在早晨和傍晚,低谷在秋季为下午14:30时(占所有行为类型56.56%)、冬季12:30时(55.61%)、春季11:00时(55.80%)。休息高峰秋季出现在12:30时(26.79%),冬季一日内呈上升趋势,春季呈双峰型,低谷在13:30时(14.64%)。从时间分配来看,寻食、取食、修饰等行为在不同季节间存在显著差异,寻食时间从高至低依次为冬季、春季、秋季,分别占总活动时间的19.87%、9.36%、3.03%;取食时间则相反,依次为秋季(72.54%)、春季(56.78%)及冬季(44.59%);与新西兰Pukepuke Lagoon种群相比,西湖湿地紫水鸡种群在秋季大量取食,在冬季增加寻食和休息时间,以应对高原湿地的温度和食物变化。修饰行为在繁殖期前(春季)最多(15.84%),繁殖期后(秋季)减少(11.10%)。以上结果说明,为适应气候、食物等条件的年周期变化,紫水鸡行为策略在不同时期和地点具有可塑性,这可能是该物种在滇西北地区得以繁衍及扩散的原因之一。     

Differences in food assimilation between two coot species assessed with stable isotopes and particle size in faeces: linking physiology and conservation

The red-knobbed coot Fulica cristata experienced a dramatic population decline in Spain, where the common coot F. atra does not face conservation problems. This is puzzling because both species have similar ecologies. It has been suggested that habitat alterations affected the quality of food plants, and this impacted differentially both coots. To verify this, we conducted experiments to determine the assimilation efficiency of both species in relation to food quality. Two types of diets differing in fibre content (commercial food and Potamogeton pectinatus) were offered to captive red-knobbed and common coots, during both spring and autumn. We examined variations in faecal particle size among coot species and diets, indicative of the facility with which food can be assimilated, and used the stable isotope technique to study differences between coot species in stable isotope fractionations from consumption to excretion. Faecal particle size was larger in red-knobbed than in common coots when fibre content was high, but was similar when it was low. Faecal particle sizes were larger in autumn, when fibre content was higher, than in spring. In general, delta(15)N in faeces of red-knobbed coots was greater than in faeces of common coots. These results suggest that the digestive efficiency of the red-knobbed coot was lower than that of the common coot, and that the differences increased when the fibre content in food plants increased. Managers should try to make available to coots wetland habitat with high quality food, which may be facilitated by prolonging the hydroperiods.     

Hawaiian waterbird movement across a developed landscape

A key component for biologists managing mobile species is understanding where and when a species occurs at different locations and scaling management to fit the spatial and temporal patterns of movement. We established an automated radio-telemetry tracking network to document multi-year movement in 2016–2018 of 3 endangered waterbirds among wetlands on Oʻahu, Hawaiʻi, USA: ʻalae ʻula or Hawaiian gallinule (gallinule; Gallinula galeata sandvicensis), ʻalae keʻokeʻo or Hawaiian coot (coot; Fulica alai), and aeʻo or Hawaiian stilt (stilt; Himantopus mexicanus knudseni), each with different ecological requirements. There were marked differences in the movement propensity of the species, with no movement among sites detected in gallinules, 31% of coots moving among wetlands, and very high levels of daily movement in stilts. A network analysis revealed strong evidence for fidelity among individual stilts to specific wetlands, indicating different groups of wetlands supported different birds. There was also strong evidence for patterns in daily and seasonal movement patterns of stilts. Our work indicates the importance of each wetland to the waterbirds they support, as each individual had strong fidelity to a single wetland. In addition, for Hawaiian coots and stilts, which were documented moving among multiple wetlands, a network of wetlands may be key for long-term persistence of these endangered species, and coordinated regional management of waterbirds as a shared resource could provide greater benefits to waterbirds than independent management of each wetland.     

High altitude tissue adaptation in Andean coots: capillarity,fibre area,fibre type and enzymatic activities of skeletal muscle

Capillarity, fibre types, fibre area and enzyme activities of different skeletal muscles (pectoralis, extensor digitorum longus), tibialis anterior, plantaris and the myocardium were compared in Andean coot (Fulica americana peruviana) native to high altitude (Junín, Perú, 4200 m) and the same species nesting at sea level. Numbers of capillaries per square millimeter were higher in all high-altitude muscles when compared with sea-level muscles (P<0.0001). Moreover, values for capillaries per fibre and capillaries in contact with each fibre were higher in digitorum and tibialis high-altitude muscles. Muscle fibres were classified as Type I, Type IIA or Type IIB on the basis of their myofibrillar ATPase pH lability. Pectoralis muscle of high-altitude and sea-level coots presented only fibres of Type IIA. In contrast, all the leg muscles studied showed a mosaic pattern of the three fibre types. Fibre areas were determined using a Leitz Texture Analysis System. Significant differences in fibre area were observed (P<0.01) between high-altitude and sea-level muscles. Mean muscle fibre diameters were also lower in the high-altitude group than in the sea-level group. The enzyme activities studied were hexokinase, lactate dehydrogenase, citrate synthase and 3-hydroxyacyl-CoA-dehydrogenase. The oxidative capacity, as reflected by citrate synthetase and hydroxyacyl-CoA-dehydrogenase activities, was greater for myocardial and pectoralis than for leg muscles. However, analysis of maximal enzyme activities showed that there were no significant differences between the glycolytic and oxidative enzyme activities of high-altitude and sea-level coots. These results suggest that in Andean coots genetically adapted to high altitude, changes in muscle capillarity and fibre size, in addition to high haemoglobin O₂ affinity and low haemoglobin concentration, are sufficient to allow adequate energy production without increases in enzymatic activities.Abbreviations BSA bovine serum albumin - C:F ratio Capillaries per fibre - CAF Capillaries in contact with each fibre - CD capillary density (mm^-2) - CS citrate synthetase - EDL muscularis digitorum longus - fra fraction reduction area - HA high altitude - HAD hydroxyacyl-CoA-dehydrogenase - HK hexokinase - LDH lactate dehydrogenase - P ₅₀ PO₂ at which hemoglobin is half saturated with O₂ - P _aO₂ arterial partial pressure of oxygen - PAS periodic acid-schiff - PEC muscularis pectoralis - PLA muscularis planaris - P _tO₂ mean tissue oxygen pressure - P _vO₂ mixed venous partial pressure of oxygen - SD standard deviation - SL sea level - TA muscularis tibialis anterior - TAS texture analysis system     

Shorebird assemblages respond to anthropogenic stress by altering habitat use in a wetland in India

Shorebirds are globally experiencing declines due to habitat loss and anthropogenic disturbance. The Central Asian Flyway hosts significant shorebirds that winter in the Indian subcontinent. The current study examined the shorebird assemblages of Kadalundi-Vallikkunnu Community Reserve, an internationally important estuarine wetland in southwestern India, to determine changes in their assemblages in relation to habitat alterations. We conducted point counts from 2005 to 2012 in mudflats, mangroves, sandy beaches and shallow water areas in Kadalundi-Vallikkunnu Community Reserve. This study measured physicochemical variables as a proxy for anthropogenic change experienced as a result of rapidly increasing human populations combined with development. We examined rainfall data during the study period to determine associations with shorebird abundance. Stepwise linear regression showed that total nitrogen and rainfall were significantly related to shorebird abundance (bird count = 306 + 213 NO₃ ^?—1.13 rainfall, F = 31.20, p < 0.001). High rainfall in a given year (one-way ANOVA F = 19.91, p < 0.001) and the previous year resulted in lower shorebird counts (one-way ANOVA F = 16.01, p < 0.001). Shorebirds declined during the study period and habitat use shifted significantly from mangroves and mudflats to sandy beaches (one-way ANOVA, F = 2.18, p = 0.034). Shorebirds also exhibited a gradual decline in diversity. We conclude that altered nutrient content in this wetland resulted in changes in the prey base in the four habitat types. Shorebirds responded to these changes by increasing the use of less preferred habitat (sandy beaches). The anthropogenic influences on the wetland are large (waste disposal, sand mining, disturbance due to development) and continued pressure may result in further decline of shorebird assemblages. The results from this study indicate that certain anthropogenic disturbances, such as waste disposal and sand mining, should be reduced to maintain and improve the integrity of this wetland.     

Effects of landscape structure on genetic diversity of Geum urbanum L. populations in agricultural landscapes

Plant species in fragmented populations are affected by landscape structure because persistence within and migration among inhabited patches may be influenced by the identity and configuration of surrounding habitat elements. This may also be true for species of the semi-natural vegetation in agricultural landscapes. To determine the effect of landscape elements we analyzed Wood Avens (Geum urbanum L.) populations within three 4×4 km² agricultural landscapes in Germany, Switzerland and Estonia, which differ in levels of land use intensity and habitat fragmentation. Genetic variation was determined in 15 randomly selected populations in each landscape using 10 microsatellite loci. The landscape structure was assessed at two circles around each population, with radii defined by the range limits of spatial genetic autocorrelation. Multiple regression analysis was used to determine the influence of landscape structure variables for inter- and intrapopulation genetic diversity. Gene diversity was equally high in Germany (H_e=0.27) and Switzerland (H_e=0.26) but lower in Estonia (H_e=0.16). A high overall inbreeding coefficient (F_IS=0.89) was found, as expected for a selfing breeding system in G. urbanum. Genetic differentiation among populations was high (overall F_ST=0.43, 0.48, and 0.45 in Estonia, Switzerland and Germany, respectively), and did not differ among the three landscapes. Only a moderate influence of individual land use types on genetic diversity within and among populations was found with some idiosyncratic relationships. Genetic variation within populations was correlated to the amount of hedgerows positively in Estonia but negatively in Switzerland. The study demonstrates that the distribution of individual land use types affects the genetic pattern of a common plant species. However, different variables were identified to influence the genetic structure in three different landscapes. This indicates a major influence of landscape-specific land use history and stochastic processes determining gene flow and plant population structure.     

Microsatellite variation, population structure, and bottlenecks in the threatened copperbelly water snake

Habitat loss and isolation is pervasive in the Midwest U.S. Wetlands are experiencing particularly dramatic declines, yet there is a paucity of information on the genetic impacts of these losses to obligate wetland vertebrates. We quantified the genetic variation of extant populations of a shallow wetland specialist and evaluated potential reductions in population size (i.e. bottlenecks) using seven polymorphic microsatellite DNA markers. We analyzed 228 copperbelly water snakes (Nerodia erythrogaster neglecta), representing populations from three states. Moderate genetic differentiation exists among all three regions (F _ST = 0.12, P < 0.001), with evidence for low levels of differentiation within the federally protected Ohio region (F _ST = 0.025, P = 0.007), and moderate to strong differentiation within the Indiana region (F _ST = 0.23, P < 0.001). Furthermore, Bayesian clustering (i.e. STRUCTURE) supports the separation of the Indiana sites, both from each other and from all other sampling sites. However, it does not support the separation of the Ohio sites from the Kentucky sites. Differentiation among sampling sites did not appear to be related to geographic distance, but rather depended on the quality of terrestrial corridors used for dispersal. Mode shifts in allele frequencies and excess heterozygosity tests were negative, while M-ratio tests were nearly all positive, indicating the likelihood of historical rather than contemporary population bottlenecks. However, potential subspecific intergradation in the Kentucky region may have artificially lowered the M-ratio, and we suggest caution when using the M-ratio approach if intergradation is suspected. Our results have conservation implications for wetland management and management of the copperbelly populations, and emphasizes the importance of protecting wetland complexes.     

Home range, movement, and site fidelity of translocated northern bobwhite (Colinus virginianus) in southwest Georgia, USA

During 1997 and 1998, we compared home range, movement, and site fidelity characteristics of translocated wild northern bobwhite (Colinus virginianus) to resident birds using radiotelemetry. We captured wild bobwhites (n=74) in southwest Georgia, USA just before the breeding season and relocated them (>1.6 km from capture sites) to sites nearby where previous density estimates revealed that populations were low compared to surrounding areas. Translocated birds were equipped with radiotransmitters and released in groups of 8 to 12. Resident birds (n=166) were also captured and simultaneously monitored via radiotelemetry. We found no difference in home range size (F ₁=0.08, P=0.78), mean daily movements (F ₁=0.04, P=0.84), or distance moved from trap or release sites to arithmetic centers of home ranges (F ₁=1.58, P=0.21) between translocated and resident bobwhites. These results suggest that translocating wild bobwhites over relatively short distances into suitable habitat does not negatively influence bobwhite movement and renders site fidelity as reasonable. Therefore, translocation of wild bobwhites before breeding season can result in enhanced numbers of adult breeders in a target location and potentially augments fall populations via reproductive yield.     

Contrasting demographic and genetic estimates of dispersal in the endangered Coahuilan box turtle: a contemporary approach to conservation

The evolutionary viability of an endangered species depends upon gene flow among subpopulations and the degree of habitat patch connectivity. Contrasting population connectivity over ecological and evolutionary timescales may provide novel insight into what maintains genetic diversity within threatened species. We employed this integrative approach to evaluating dispersal in the critically endangered Coahuilan box turtle (Terrapene coahuila) that inhabits isolated wetlands in the desert‐spring ecosystem of Cuatro Ciénegas, Mexico. Recent wetland habitat loss has altered the spatial distribution and connectivity of habitat patches; and we therefore predicted that T. coahuila would exhibit limited movement relative to estimates of historic gene flow. To evaluate contemporary dispersal patterns, we employed mark–recapture techniques at both local (wetland complex) and regional (intercomplex) spatial scales. Gene flow estimates were obtained by surveying genetic variation at nine microsatellite loci in seven subpopulations located across the species’ geographical range. The mark–recapture results at the local spatial scale reveal frequent movement among wetlands that was unaffected by interwetland distance. At the regional spatial scale, dispersal events were relatively less frequent between wetland complexes. The complementary analysis of population genetic substructure indicates strong historic gene flow (global F_ST = 0.01). However, a relationship of genetic isolation by distance across the geographical range suggests that dispersal limitation exists at the regional scale. Our approach of contrasting direct and indirect estimates of dispersal at multiple spatial scales in T. coahuila conveys a sustainable evolutionary trajectory of the species pending preservation of threatened wetland habitats and a range‐wide network of corridors.     

Habitat fragmentation influences genetic diversity and differentiation: Fine‐scale population structure of Cercis canadensis (eastern redbud)

Forest fragmentation may negatively affect plants through reduced genetic diversity and increased population structure due to habitat isolation, decreased population size, and disturbance of pollen‐seed dispersal mechanisms. However, in the case of tree species, effective pollen‐seed dispersal, mating system, and ecological dynamics may help the species overcome the negative effect of forest fragmentation. A fine‐scale population genetics study can shed light on the postfragmentation genetic diversity and structure of a species. Here, we present the genetic diversity and population structure of Cercis canadensis L. (eastern redbud) wild populations on a fine scale within fragmented areas centered around the borders of Georgia–Tennessee, USA. We hypothesized high genetic diversity among the collections of C. canadensis distributed across smaller geographical ranges. Fifteen microsatellite loci were used to genotype 172 individuals from 18 unmanaged and naturally occurring collection sites. Our results indicated presence of population structure, overall high genetic diversity (H_E = 0.63, H_O = 0.34), and moderate genetic differentiation (F_ST = 0.14) among the collection sites. Two major genetic clusters within the smaller geographical distribution were revealed by STRUCTURE. Our data suggest that native C. canadensis populations in the fragmented area around the Georgia–Tennessee border were able to maintain high levels of genetic diversity, despite the presence of considerable spatial genetic structure. As habitat isolation may negatively affect gene flow of outcrossing species across time, consequences of habitat fragmentation should be regularly monitored for this and other forest species. This study also has important implications for habitat management efforts and future breeding programs.