Kelly Catherine L, Schwarzkopf Lin, Gordon Iain J, Hirsch Ben
Division of Tropical Environments and Societies James Cook University Townsville Qld Australia.
Fenner School of Environment & Society Australian National University Canberra ACT Australia.
Ecol Evol. 2021 Mar 9;11(9):4577-4587. doi: 10.1002/ece3.7352. eCollection 2021 May.
When introduced to new ecosystems, species' populations often grow immediately postrelease. Some introduced species, however, maintain a low population size for years or decades before sudden, rapid population growth is observed. Because exponential population growth always starts slowly, it can be difficult to distinguish species experiencing the early phases of slow exponential population growth (inherent lags) from those with actively delayed growth rates (prolonged lags). Introduced ungulates provide an excellent system in which to examine lags, because some introduced ungulate populations have demonstrated rapid population growth immediately postintroduction, while others have not. Using studies from the literature, we investigated which exotic ungulate species and populations ( = 36) showed prolonged population growth lags by comparing the doubling time of real ungulate populations to those predicted from exponential growth models for theoretical populations. Having identified the specific populations that displayed prolonged lags, we examined the impacts of several environmental and biological variables likely to influence the length of lag period. We found that seventeen populations (47%) showed significant prolonged population growth lags. We could not, however, determine the specific factors that contributed to the length of these lag phases, suggesting that these ungulate populations' growth is idiosyncratic and difficult to predict. Introduced species that exhibit delayed growth should be closely monitored by managers, who must be proactive in controlling their growth to minimize the impact such populations may have on their environment.
当被引入新的生态系统时，物种数量在释放后往往会立即增长。然而，一些外来物种在观察到突然、快速的种群增长之前，其种群数量会在数年或数十年间维持在较低水平。由于种群指数增长总是从缓慢开始，因此很难区分处于缓慢指数增长早期阶段（固有滞后）的物种和那些增长率被主动延迟的物种（延长滞后）。外来有蹄类动物提供了一个研究滞后现象的绝佳系统，因为一些外来有蹄类动物种群在引入后立即表现出快速的种群增长，而其他种群则没有。利用文献中的研究，我们通过比较实际有蹄类动物种群的翻倍时间与理论种群指数增长模型预测的翻倍时间，调查了哪些外来有蹄类物种和种群（n = 36）表现出延长的种群增长滞后。在确定了表现出延长滞后的特定种群后，我们研究了几个可能影响滞后期长度的环境和生物变量的影响。我们发现17个种群（47%）表现出显著延长的种群增长滞后。然而，我们无法确定导致这些滞后期长度的具体因素，这表明这些有蹄类动物种群的增长具有特殊性且难以预测。表现出增长延迟的外来物种应由管理者密切监测，管理者必须积极主动地控制它们的增长，以尽量减少这些种群可能对其环境造成的影响。
