摘要
地中海隼(Falco biarmicus feldeggii)是欧洲濒危程度最高的物种之一。其全球数量估计不超过几百对,不均匀分布于西西里至里海的广阔而片断化的地区。最近统计表明,西西里地中海隼在全部种群数量中占很大比例(>25%)。因此,意大利政府提出一项国家行动计划。在这一计划框架下,我们在意大利进行了首次地中海隼种群数量的全国调查(2003～2004年)。本研究的地理范围包括地中海隼的整个繁殖区,即西西里和意大利半岛(n=2909栅格单元,10km×10km)。另外,我们尽量考虑了以往(1993～2001年)区域调查的结果。我们对各个繁殖亚群的大小和分布进行评估,鉴别在景观尺度上与巢址空间分布相关的主要环境特征。在184个栅格单元(全部栅格地图的6.4%)中发现有地中海隼的存在,但同一繁殖期内地中海隼数量估计不超过140～172对(其中70～80对分布于西西里)。大陆繁殖栅格的隔离程度较高,而西西里地区的单元更为密集。海拔高度是意大利单元聚集性的主要影响因素;另外气候、降水量和植被等环境因素对此也有重要影响。本研究表明保护区内的处于繁殖期的地中海隼数量较少(23%～28%),意大利政府的保护措施还不够完善。在适于地中海隼巢址不规则空间聚集的优先性生境保护方面,多个小型、分散分布的特定保育区(SAC)优于大型特定保护区(SPA)。
Falco biarmicus feldeggii is one of the most threatened taxa in Europe.Its global population is estimated at a few hundred pairs unequally scattered in a vast and fragmented area stretching from Sicily to the Caspian Sea.Most recent counts showed that Italy hosts a large part (>25%) of the whole population.Consequently,Italian authorities promoted a national action plan.In this framework,we carried out the first national survey for the Lanner Falcon in Italy (2003-2004).Our study area covered the whole breeding range,i. e.,Sicily and the Italian peninsula (n=2909 cells 10×10 km).When possible,we considered also additional information from previous regional investigations (1993-2001).First,we estimated size and distribution of each breeding subpopulation.Then,we tried to identify, at landscape level,the main environmental features linked to the spatial distribution of the nesting sites.We found the Lanner Falcon in 184 cells (6.4% of the total grid map),but we estimated no more than 140-172 pairs (70-80 of which are in Sicily) in the same breeding season.Higher levels of isolation characterize the continental breeding cells whereas in Sicily cells are much more clustered.Altitude is the main factor influencing cell aggregations in Italy;nevertheless,other environmental variables,such as climate,precipitation,and vegetation may be important.Our results show that the conservation measures adopted in Italy are somewhat inadequate given the low number of breeding pairs included in protected areas (23%-28%).Many small and scattered special areas of conservation (SAC) devoted to conserve priority habitats fit the irregular spatial aggregations of Lanner Falcon sites better than several large special protection areas (SPA).
