Fredrickson Richard J, Hedrick Philip W
School of Life Sciences, Arizona State University, Tempe, Arizona 85287-4601, USA.
Conserv Biol. 2006 Aug;20(4):1272-83. doi: 10.1111/j.1523-1739.2006.00401.x.
Hybridization and introgression are significant causes of endangerment in many taxa and are considered the greatest biological threats to the reintroduced population of red wolves (Canis rufus) in North Carolina (U.S.A.). Little is known, however, about these processes in red wolves and coyotes (C. latrans). We used individual-based simulations to examine the process of hybridization and introgression between these species. Under the range of circumstances we considered, red wolves in colonizing and established populations were quickly extirpated, persisted near the carrying capacity, or had intermediate outcomes. Sensitivity analyses suggested that the probabilities of quasi extinction and persistence of red wolves near the carrying capacity were most affected by the strength of two reproductive barriers: red wolf challenges and assortative mating between red wolves and coyotes. Because model parameters for these barriers may be difficult to estimate, we also sought to identify other predictors of red wolf population fate. The proportion of pure red wolves in the population was a strong predictor of the future probabilities of red wolf quasi extinction and persistence. Finally, we examined whether sterilization can be effective in minimizing introgression while allowing the reintroduced red wolfpopulation to grow. Our results suggest sterilization can be an effective short-term strategy to reduce the likelihood of extirpation in colonizing populations of red wolves. Whether red wolf numbers are increased by sterilization depends on the level of sterilization effort and the acting reproductive barriers. Our results provide an outline of the conditions likely required for successful reestablishment and long-term maintenance of populations of wild red wolves in the presence of coyotes. Our modeling approach may prove generally useful in providing insight into situations involving complex species interactions when data are few.
杂交和基因渗入是许多分类群濒危的重要原因，被认为是对美国北卡罗来纳州重新引入的红狼（Canis rufus）种群最大的生物学威胁。然而，对于红狼和郊狼（C. latrans）之间的这些过程，人们知之甚少。我们使用基于个体的模拟来研究这两个物种之间的杂交和基因渗入过程。在我们考虑的一系列情况下，定居种群和已建立种群中的红狼迅速灭绝、在承载能力附近持续存在，或出现中间结果。敏感性分析表明，红狼接近承载能力时准灭绝和持续存在的概率受两个生殖屏障强度的影响最大：红狼的挑战以及红狼与郊狼之间的选型交配。由于这些屏障的模型参数可能难以估计，我们还试图确定红狼种群命运的其他预测因素。种群中纯红狼的比例是红狼准灭绝和持续存在未来概率的有力预测因素。最后，我们研究了绝育在尽量减少基因渗入的同时允许重新引入的红狼种群增长方面是否有效。我们的结果表明，绝育可以作为一种有效的短期策略，以降低红狼定居种群灭绝的可能性。绝育是否能增加红狼数量取决于绝育努力的程度和起作用的生殖屏障。我们的结果概述了在有郊狼存在的情况下成功重建和长期维持野生红狼种群可能需要的条件。当数据很少时，我们的建模方法可能普遍有助于深入了解涉及复杂物种相互作用的情况。
