中国陕西宁陕朱鹮(Nipponia Nippon)再引入项目效果评估

【作者】 王敏；

【导师】 于晓平；

【作者基本信息】 陕西师范大学 ， 生态学， 2015， 硕士

【摘要】 再引入是把物种人工繁殖或者野外捕获的个体释放到其历史分布区以期建立一个能自我维持种群的尝试,是目前濒危物种易地保护最为广泛使用的手段。由于再引入花费巨大,成功率低,因此在实施之前要进行严格的可行性评估,引入后要进行长期的释放后监测以便对再引入的效果进行评估。虽然再引入的长期目标是建立一个自由生活的可自我维持的种群,但是再引入的进展是由一系列目标组成的,包括释放个体的存活,释放个体及其后代参加繁殖以及重建种群的持续性。每个阶段都应该用合适的方法来进行评估,而且也越来越强调释放后监测在评估中的重要性。朱鹮(Nipponia nippon)是世界濒危鸟类,自1981年野生种群重新发现以来,国内外都开展了广泛深入的保护工作。经过30多年的保护,野生种群不断扩大,人工圈养种群也达到了1,000多只。为了彻底地保护这一物种,避免意外灾害对这个物种的伤害,有关专家经过多地考察,最终决定在宁陕县开展朱鹮的再引入工作。2007年5月,世界上首个朱鹮再引入项目在宁陕县实施。2007-2011间,共计释放个体56只,释放后对释放种群进行了长期的跟踪监测。为了评估濒危物种朱鹮再引入的进展情况,检验种群是否可以自我维持,为其他地方的朱鹮再引入及其他物种再引入提供一些指导和预测。本文分析了种群释放后的长期监测数据,估算了种群统计学参数(存活率、繁殖成功率),并且和野生朱鹮种群的数据作了比较。本文用Cormack-Jolly-Seber模型(CJS model)估算了释放个体的存活率,用Live-Recovery模型(LD model)估算了野外出生个体不同年龄组的存活率并且分析了影响存活率的原因。计算了2008-2014年间朱鹮种群的繁殖成功率以及种群目前的年龄结构和性比。研究结果表明：(1)释放个体第一年存活率为0.571,用CJS模型估算出释放个体平均年存活率为0.769±0.074,存活率的年间变化极显著(t=10.406,P=0.000,df=7)；(2)用LD模型估算出野外出生个体中成体年存活率为0.941±0.041,与野生种群的存活率相近。当年幼鸟的存活率较低,为0.549±0.066； (3)再引入种群的平均窝卵数为3.22+0.84(n=46),年间变化差异不显著(F=0.765,df=6,P=0.602),野生种群的平均窝卵数为2.844±0.77(n=271)； (4)宁陕再引入种群的平均孵化率为69.1%,7年间孵化率差异显著(F=2.481,P=0.040,df=6),其中卵损失的原因是无精卵或天敌捕食,如王锦蛇(Elaphe carinata)等；幼鸟的平均出飞率为73.6%(57.1%-84.6%),雏鸟死亡原因主要包括：自然死亡、天敌捕食、亲鸟弃巢等； (5)再引入种群的繁殖成功率(52.5%)相对野生种群(67.6%)较低；(6)卵的孵化率与繁殖成功率有着明显的相关关系(r=0.847,P=0.016<0.05);幼鸟的出飞率与繁殖成功率相关性也极显著(r=0.910,P=0.004<0.05)； (7)再引入种群中,繁殖前期个体和繁殖期个体所占比例分别为42.5%和50%,老年个体所占比例为7.5%。研究的40只个体中,雄性22只,雌性18只,性比为55%。通过陕西宁陕、日本佐渡岛朱鹮再引入种群和洋县野生种群相关数据的比较,按照国际自然保护联盟(IUCN)物种再引入指南的相关定义和要求,本文认为到目前为止宁陕朱鹮再引入项目是成功的。再引入种群繁殖成功率虽然较野生种群为低,但是随着参与繁殖后代数逐渐增多,老年个体参与繁殖比例减少,种群的繁殖成功率会有增加的趋势,种群数量会有所增加,即使在没有补充释放的情况下也可自我维持。本研究的结论主要有：(1)陕西宁陕朱鹮再引入是关于该物种的世界首例再引入项目,目前所取得的成果可以作为该物种后续释放的良好范例。(2)一项成功的再引入需要有适宜的栖息地环境、建群种数量不少于20只、软释放更有助于个体尽快适应环境。(3)卫星种群的形成促进了各小种群之间的基因交流,把再引入种群和源种群联系起来,表明再引入种群已经适应环境并且呈现与原种群相似的行为反应。(4)对人工投食的依赖也可能是野外放飞朱鹮长期居留的原因,因此在繁殖期和游荡期内,人工投喂食物,可以保证更多朱鹮能成功存活。 (5)对于领域行为不太明显的朱鹮种群,在同一个地点多次释放个体,后释放个体可以向先前释放个体学习生存技能,并且可以促进新繁殖配对的形成,如需释放可以优先考虑在笼养期间内有过繁殖经验的个体。更多还原

【Abstract】 Reintroduction projects attempt to re-establish a self-sustaining population for endangered species within their historical ranges, usually through the release of captive-bred or wild-caught individuals into the wild. Reintroduction is a frequently used tool in the conservation of endangered species. Due to the high financial costs and low success rate, rigorous assessment of feasibility is essential prior to implementation as well as appropriately long post-release monitoring to assess success. Although the aim of a reintroduction is to establish a free-living, self-sustaining population, the progress of a reintroduction comprises a sequence of objectives, including the survival of released individuals, breeding by released individuals in the wild and then subsequent growth and persistence of the population. Each of these stages should be assessed by appropriate method and the importance of post-release monitoring has been emphasized in assessing progress with reintroduction projects. In many cases, even today, monitoring is found to be inadequate to appropriately assess success or failure.The Crested Ibis (Nipponia Nippon) is one of the world’s endangered species. The intensive conservation work has been carried out both at home and abroad since the rediscovery of wild population in 1981. After 30 years of protection, wild population expanding, captive breeding population has reached more than 1,000. Now there is only one wild population remaining in the world, it has been suggested that the captive-bred individuals of the Crested Ibis should gradually be reintroduced to other parts of its former range in China, as the wild population is currently vulnerable to extinction through a chance catastrophe within its limited range. After pre-surveys on potential release site in 9 provinces in China, the Ningshan County was confirmed the first reintroduction area. Hence, the world’s first Crested Ibis reintroduction project implemented in Ningshan County, May 2007. A total of 56 individuals were successively released to wild between 2007 and 2011 and long-term post-release monitoring has been continuing after release.In order to orient and adjust future management activities, predicting whether it is a sustainable population, we here assess the initial reintroduction program in Ningshan County for the endangered Crested Ibis by analyzing post-release monitoring data, evaluating demographic parameters (survival, breeding success), then compared the results with published data on wild Crested Ibis population. Survival was estimated by Cormack-Jolly-Seber model (CJS model), survival of different age groups was estimated by Live-Recovery model. Breeding success, age structure and sex ratio were also calculated among 2008-2014.Our results indicated that:(1) The first year survival of released individuals was 57.1%, eatimated average annual survival of 56 released Crested Ibis by CJS model was 0.769±0.074 and varied among years (t=10.406,P=0.000, df=6); (2) Estimated survival of wild born adults and nestlings was 69.3% and 48.1%, respectively by Joint Live and Dead Encounters model (LD model); (3) Clutch size of reintrodued population was 3.22±0.84 (n=46) with no signigicant variation among years (F=0.765, df=6, P=0.602), while wild population was 2.84±0.77 (n=271); (4) Hatching success was 69.1%, and varied significantly among 7 years (F=2.481, P=0.040,df=6), loss of egges are mainly due to infertile eggs and predation by predators such as King Rat Snake (Elaphe carinata), fledging success of nestlings was 73.6%(57.1%-84.6%), death of nestlings were caused by nature, predation and abanonment by parents; (5) breeding success (52.5%) of reintroduced population was lower than wild population (67.6%); (6)There is a siginificant correlation bewtween hatching success and breeding success (r=0.847, P=0.016<0.05), fleging success of nestlings was obviously related to breeding success (r=0.910, P<0.004<0.05); (7) Among the 40 individuals we investigated, the proportion of pre-breeding Crested Ibis (0-2 yr) was 42.5%, individuals among breeding age (>2 yr) was 50%. Number of female was 22, male 18 and the sex ratio was 55%.By comparing relevant data of reintroduced population with wild population and Japanese reintroduced population, we assume that that our reintroduced population is self-sustainable based on the survival and fecundity data. Although breeding success of reintroduced population is relatively lower than wild population, it may be increase with the increase of more offspring involved in breeding. Thus, population size would increase and be self-sustaining without any additional release.The conclusion of this study mainly include:(1) The achievement of the initial reintroduction project of Crested Ibis in Ninshan County, Shaanxi Province is an good example for subsequent release of this species. (2) A successful reintroduction requires suitable habitat, founder population size no less than twenty and soft release may help the individuals adapt to the environment as soon as possible. (3) The formation of satellite population facilitates gene exchange among small population and associates reintroduced population with wild population, it shows that the releae stocks have adapt to the environment and present similar behavior pattern with source population. (4) Dependment on provisioning may be the cause of released individuals stay at release site, so food supplement in breeding and wandering stage may guarantee more Crested Ibis to survive. (5) For the Crested Ibis who have no obvious territory behavior, continued release at one site can contribute to later released individuals learn survive skills from former released individuals as well as formation of new breeding pairs. If possible, birds that have previously bred in captivity should be considered firstly.更多还原