Powell Roger A, Facka Aaron N, Clifford Deana L, Smith Kevin P, Matthews Sean M, Murphy Ed, Yaeger J Scott, Figura Pete, Callas Richard
Department of Applied Ecology, North Carolina State University, Raleigh, North Carolina, United States of America.
Wildlife Investigations Laboratory, California Department of Fish & Wildlife, Rancho Cordova, California, United States of America.
PLoS One. 2025 Apr 30;20(4):e0320594. doi: 10.1371/journal.pone.0320594. eCollection 2025.
Reintroductions to establish populations usually occur in locations believed to have high-quality habitat to maximize the potential for high population growth rates and long-term population viability. Nonetheless, researchers and managers may have insufficient knowledge of what comprises high-quality habitat or of other requirements for members of a species with low population sizes or how to determine whether these conditions are present at potential reintroduction sites. Locations available for reintroduction may lack optimal habitat but have other characteristics that can benefit a reintroduction. Reintroductions allow rigorous study of reintroduced animals to improve understanding of a species' biology and to inform future management and conservation actions. The fisher, a medium sized carnivoran in the family Mustelidae, is a long-lived (5-8 years) species of concern in western North America due, in part, to the perceived incompatibility of fishers and landscapes commercially managed for timber production. Due to concern about the status of fishers in California, from late 2009 to late 2011 we reintroduced 40 fishers from across northwestern California to the 648 km2, privately owned Stirling Management Area that was managed intensively for timber production in the northern Sierra Nevada and southern Cascades of California. The controlled initial conditions facilitated research into other aspects of fisher biology. We monitored reintroduced fishers and their offspring through 2017 to evaluate whether this managed landscape in California, predicted to possess adequate habitat for fishers, could support a new fisher population. Both female and male fishers had high monthly survival (>0.95). On average, 81% of adult females gave birth with a mean litter size of 1.9 ± 0.1 (minimum number of kits ±95% confidence interval). Survival and reproduction rates were constant across years and all vital rates were similar to most extant fisher populations elsewhere in California. By 2013, reproduction was effectively independent of the founding individuals. By 2017, the population was relatively small (n = 119 ± 96-141, 95% credible intervals) but had nearly tripled over the initial number reintroduced. Stochastic population simulations indicated that the population is unlikely to go extinct within the first 50 years after reintroduction, or 40 years after the completion of field research. Nevertheless, significant habitat changes resulting from wildfire could change those predictions. Thus, sites with landscape conditions similar to our study site and managed similarly for timber production should be considered when planning future fisher reintroductions.
为建立种群而进行的重新引入通常发生在被认为拥有高质量栖息地的地方，以最大限度地提高高种群增长率和长期种群生存能力的可能性。然而，研究人员和管理人员可能对什么构成高质量栖息地、对种群数量较少的物种成员的其他需求了解不足，或者不知道如何确定这些条件在潜在的重新引入地点是否存在。可供重新引入的地点可能缺乏最佳栖息地，但具有其他有利于重新引入的特征。重新引入使得对重新引入的动物进行严格研究成为可能，从而增进对物种生物学的理解，并为未来的管理和保护行动提供信息。渔貂是鼬科的一种中型食肉动物，寿命较长（5 - 8年），在北美西部受到关注，部分原因是人们认为渔貂与以商业方式管理木材生产的景观不相容。由于对加利福尼亚州渔貂状况的担忧，从2009年末到2011年末，我们将来自加利福尼亚州西北部各地的40只渔貂重新引入到面积为648平方公里的私人拥有的斯特林管理区，该区域位于加利福尼亚州内华达山脉北部和喀斯喀特山脉南部，曾被集约管理用于木材生产。可控的初始条件便于对渔貂生物学的其他方面进行研究。我们对重新引入的渔貂及其后代进行了监测，一直持续到2017年，以评估加利福尼亚州这片预计拥有适合渔貂栖息地的管理景观是否能够支持一个新的渔貂种群。雌性和雄性渔貂的月生存率都很高（>0.95）。平均而言，81%的成年雌性产仔，平均窝仔数为1.9 ± 0.1（幼崽最小数量 ± 95%置信区间）。多年来生存率和繁殖率保持稳定，所有生命率与加利福尼亚州其他地方现存的大多数渔貂种群相似。到2013年，繁殖实际上已独立于最初引入的个体。到2017年，种群规模相对较小（n = 119 ± 96 - 141，95%可信区间），但几乎是最初重新引入数量的三倍。随机种群模拟表明，该种群在重新引入后的头50年内或野外研究结束后的40年内不太可能灭绝。然而，野火导致的重大栖息地变化可能会改变这些预测。因此，在规划未来的渔貂重新引入时，应考虑具有与我们研究地点相似的景观条件且同样用于木材生产管理的地点。
