Beasley James C, Atwood Todd C, Byrne Michael E, Vercauteren Kurt C, Johnson Shylo R, Rhodes Olin E
University of Georgia, Savannah River Ecology Laboratory, Aiken, South Carolina, United States of America.
USDA APHIS Wildlife Services, National Wildlife Research Center, Fort Collins, Colorado, United States of America.
PLoS One. 2015 Jan 14;10(1):e0113206. doi: 10.1371/journal.pone.0113206. eCollection 2015.
Despite the widespread use of aerial baiting to manage epizootics among free-ranging populations, particularly in rabies management, bait acceptance and seroconversion rates often are lower than required to eliminate spread of disease. Our objectives in this study, therefore, were to evaluate the performance of stratified bait distribution models derived from resource selection functions (RSF) on uptake of placebo rabies baits by raccoons (Procyon lotor) and Virginia opossums (Didelphis virginiana), as well as the probability of bait uptake as a function of proximity to bait distribution areas in fragmented agricultural ecosystems. Among 478 raccoons and 108 opossums evaluated for presence of Rhodamine B (RB) across 8 sites, only 26% of raccoons and 20% of opossums exhibited marking consistent with bait consumption 14-24 days post-baiting. The effective area treated, based on 90% kernel density estimators of marked individuals, ranged from 99-240 ha larger than bait distribution zones, with RB marked individuals captured up to 753 m beyond the bait zone. Despite incorporation of RSF data into bait distribution models, no differences in uptake rates were observed between treatment and control sites. These data likely reflect the underlying constraints imposed by the loss and fragmentation of habitat on animal movement in heterogeneous landscapes, forcing individuals to optimize movements at coarse (i.e., patch-level) rather than fine spatial scales in highly fragmented environments. Our data also confirm that the probability of bait acceptance decreases with increasing distance from bait zone interiors, even within the zone itself. Thus, although bait acceptance was confirmed beyond bait zone boundaries, the proportion of vaccinated individuals may comprise a small minority of the population at increasing distances from baiting interiors. These data suggest focal baiting creates a buffered area of treated individuals around bait zones or bait stations, but repeated treatments may be needed to achieve sufficient uptake to eradicate disease.
尽管空中投饵被广泛用于管理自由放养种群中的动物流行病，尤其是在狂犬病管理方面，但诱饵接受率和血清转化率往往低于消除疾病传播所需的水平。因此，我们在本研究中的目标是评估从资源选择函数（RSF）得出的分层诱饵分布模型对浣熊（Procyon lotor）和弗吉尼亚负鼠（Didelphis virginiana）摄取安慰剂狂犬病诱饵的效果，以及在破碎化农业生态系统中，诱饵摄取概率与距诱饵分布区域的距离之间的函数关系。在8个地点对478只浣熊和108只负鼠进行罗丹明B（RB）检测，诱饵投放后14 - 24天，只有26%的浣熊和20%的负鼠表现出与食用诱饵一致的标记。根据标记个体的90%核密度估计，有效处理面积比诱饵分布区大99 - 240公顷，在诱饵区外753米处捕获到有RB标记的个体。尽管将RSF数据纳入了诱饵分布模型，但处理组和对照组之间的摄取率没有差异。这些数据可能反映了栖息地丧失和破碎化对异质景观中动物移动造成的潜在限制，迫使个体在高度破碎化的环境中在粗略（即斑块水平）而非精细空间尺度上优化移动。我们的数据还证实，即使在诱饵区内，诱饵接受概率也会随着距诱饵区内部距离的增加而降低。因此，尽管在诱饵区边界外也证实有诱饵被接受，但随着距诱饵投放内部距离的增加，接种个体的比例可能只占种群的一小部分。这些数据表明，定点投饵在诱饵区或诱饵站周围创建了一个经过处理个体的缓冲区，但可能需要重复投饵才能实现足够的摄取率以根除疾病。
