CRB: Population Size and Density Effects on Population Viability: A Case Study of Two Cirsium Species

随着时间的推移，在一个地方，常见的物种往往会保持 常见而稀有的物种仍然罕见。 生物学家一直以来 有兴趣确定哪些因素或过程调节或 控制人口规模。 最近，人类的影响 减少某些物种丰度的活动， 变得更加明显。 随着人们对保护 生物多样性已经成为一种尝试， 影响珍稀濒危物种的生存。 这项研究调查了人口规模对 这些群体中的个体植物的表现。 产于新墨西哥州山区的两种蓟 将被研究：一个稀有物种（作为联邦保护 濒危物种）和其他更常见的蓟 类似的环境。 不同规模的人口（范围 从10到3000多人）将从已知的 稀有物种的种群;这些种群中的个体植物 将对人口进行监测。类似的观察将是 在普通物种的人工种群上进行， 这将是建立与植物移植的 调查员 种子存活率估计 生产，等等，在这些人口将被用于 计算机模型来评估可行性（ 持续存在）的极少数人口的 濒危物种 这项研究将阐明调节 植物的种群数量，包括常见的和罕见的。 研究 还将测试评估小型 人口。 这些技术对土地管理者和 政府机构决定哪些物种或 种群是值得保护的候选者。

Over time in a location, common species tend to remain common while rare species remain rare. Biologists have long been interested in determining what factors or processes regulate or control population size. Recently, the effect of human activities in decreasing the abundance of some species has become more apparent. With increasing interest in protecting biological diversity has come an attempt to identify the factors affecting the survival of rare and endangered species. This research investigates the effects of population size on the performance of individual plants within those populations. Two species of thistle occurring in the mountains of New Mexico will be studied: one a rare species (protected as a federally Threatened species) and the other a more common thistle of similar environments. Populations of different sizes (ranging from 10 to over 3000 individuals) will be selected from known populations of the rare species; individual plants within these populations will be monitored. Similar observation will be carried out on artificial populations of the common species, which will be established with plants transplanted by the investigator. Estimates of the rates of survival, seed production, and so on in these populations will be used in computer models to assess the viability (the chances for continued persistence) of extremely small populations of the threatened species. This research will shed light on the processes that regulate population size in plants, both common and rare. The research will also test methods for assessing the viability of small populations. Such techniques are essential for land managers and government agencies making decisions about which species or populations are worthy candidates for conservation efforts.