背景:了解景观特征如何影响动物的运动对于在人类主导的栖息地中进行保护至关重要。一个基本的问题是如何单一种植农林,包括橡胶和茶园,影响野生动物及其运动。实验性易位代表了一种重要的技术来评估动物的栖息地选择,同时通过农业基质,特别是当与鸟类的自然运动的观察补充,和“控制”易位,鸟类在其自然栖息地如森林中移动。然而,实验性易位很少用于西半球以外的鸟类。
方法:我们对一名林下森林专家进行了实验性易位和家庭范围测量,棕色封顶的巴布勒(BCBA,Pellorneumfuscocillus),一个森林通才,Tickell\'sBlueFlycatcher(TBFL,Cyornistickelliae)。这些物种在三个橡胶种植园中进行了研究,其中还包括一些主要种植茶叶的开放区域,和斯里兰卡的三个森林保护区。
结果:在受干扰的栖息地(橡胶种植园)内转移的五个BCBA中有四个无法返回其捕获位置。然而,未受干扰的栖息地(森林保护区)内的所有四个个体在10.5白天小时内成功返回了起点。相比之下,所有TBFL在白天11.3小时内返回受干扰(n=7)和未受干扰的栖息地(n=3)的捕获位置。Cox比例生存模型表明,橡胶覆盖的百分比减少了返回时间,类似于开放区域覆盖的效果。家庭范围调查(BCBA的n=13,对于TBFL,n=10)表明,很少的鸟类自然栖息地被橡胶覆盖(对于BCBA,为0.2%,在50%内核密度估计KDE下,TBFL为13.1%)。与未受干扰的栖息地相比,BCBA的家园范围约为受干扰栖息地的一半,尽管TBFL的栖息地之间没有显着差异。
结论:我们得出的结论是,橡胶种植园对于林下栖息地的专业鸟类来说是不可渗透的,甚至通才物种也可能长期避免它们。我们的发现强调了原生植被条的潜在效用,特别是那些以底层为特征的,作为走廊,以促进森林专家在以橡胶种植园和其他类型的受干扰栖息地为主的景观中的移动。
BACKGROUND: Understanding how landscape characteristics affect animal movement is essential for conservation in human-dominated habitats. A fundamental question is how monoculture agroforests, including rubber and tea plantations, affect wildlife and its movement. Experimental
translocations represent an important technique to assess animals\' habitat selection while moving through agricultural matrices, especially when complemented with observations of birds\' natural movements, and with \"control\"
translocations, in which birds are moved within their natural habitat such as forest. Yet, experimental
translocations have been little used for birds outside the Western Hemisphere.
METHODS: We conducted experimental
translocations and home-range measurements on an understory forest specialist, Brown-capped Babbler (BCBA, Pellorneum fuscocapillus), and a forest generalist, Tickell\'s Blue Flycatcher (TBFL, Cyornis tickelliae). These species were studied in three rubber plantations, which also included some open areas mostly planted with tea, and in three forest reserves of Sri Lanka.
RESULTS: Four of the five BCBAs translocated within disturbed habitats (rubber plantations) could not return to their capture locations. However, all four individuals within undisturbed habitats (forest reserves) successfully returned to their point of origin within 10.5 daytime hours. In contrast, all TBFLs returned to their capture locations in both disturbed (n = 7) and undisturbed habitats (n = 3) within 11.3 daytime hours. A Cox-proportional survival model demonstrated that the percentage of rubber cover decreased return time, similar to the effect of open-area cover. The home range surveys (n = 13 for BCBA, n = 10 for TBFL) revealed that very little of the birds\' natural home-ranges was covered by rubber (0.2% for BCBA, 13.1% for TBFL at 50% Kernel Density Estimates KDE). Home range size for BCBA was approximately half the size in disturbed habitats compared to undisturbed ones, although there was no significant difference between habitats for TBFL.
CONCLUSIONS: We conclude that rubber plantations can be impermeable to understory habitat specialist birds, and even generalist species may avoid them long-term. Our findings highlight the potential utility of strips of native vegetation, particularly those featuring understory layers, as corridors to facilitate the movement of forest specialists in landscapes dominated by rubber plantations and other types of disturbed habitats.