PDF(Pubmed)
Abstract：
Invasive alien species control is recognized worldwide as a priority action to preserve global biodiversity. However, a lack of general life history knowledge for threatened species can impede the effectiveness of conservation actions. Galápagos pink land iguanas (Conolophus marthae) are endemic to Wolf Volcano, Galápagos, Ecuador. These iguanas are threatened by invasive alien species, particularly feral cats, that may affect their small population size. To guarantee the long-term survival of C. marthae, the Galápagos National Park Directorate is considering, along with an ongoing campaign of feral cat control, the implementation of a head-start program. However, the success of this management strategy necessarily relies on the identification of pink iguana nesting grounds, which were still unknown at the onset of this study. We modeled the movement patterns of male and female iguanas during the reproductive season, using location data collected from custom-made remote tracking devices installed on adult pink iguanas in April 2021. We first calculated for each individual the vector of distances from its starting location, which was defined as net displacement. We then used net displacement as the response variable in a generalized additive mixed model with day of the year as the predictor. Based on the hypothesis that males and females may behaviorally differ after mating, we looked for female-specific migratory behavior suggesting females were moving toward nesting areas. The results obtained confirmed our hypothesis, as females exhibited a distinct migratory behavior, reaching a small plateau area inside of Wolf Volcano\'s caldera and ca. 400 m below the volcano\'s northern rim. Moreover, once inside the caldera, females displayed a more aggregated distribution pattern. The movement data obtained allowed Galápagos National Park rangers to locate individual pink iguana nests and subsequently to sight and collect the first observed hatchlings of the species. This work constitutes a necessary baseline to perform dedicated studies of pink iguana nests and emerging hatchling iguanas, which is an essential step toward the development of an effective head-start program.
摘要：
外来入侵物种控制在世界范围内被认为是保护全球生物多样性的优先行动。然而,缺乏受威胁物种的一般生活史知识会阻碍保护行动的有效性。加拉帕戈斯粉红色土地鬣蜥（Conolophusmarthae）是狼火山特有的，加拉帕戈斯,厄瓜多尔。这些鬣蜥受到外来入侵物种的威胁，尤其是野猫，这可能会影响他们的人口规模。为了保证Marthae的长期生存,加拉帕戈斯国家公园管理局正在考虑,以及正在进行的野猫控制运动，一个首当其冲的程序的实现。然而,这种管理策略的成功必然依赖于粉红色鬣蜥筑巢地的识别，在这项研究开始时仍然未知。我们模拟了雄性和雌性鬣蜥在繁殖季节的运动模式，使用从2021年4月安装在成年粉红色鬣蜥上的定制远程跟踪设备收集的位置数据。我们首先为每个个体计算其起始位置的距离向量，被定义为净位移。然后，我们在以一年中的某一天为预测指标的广义加性混合模型中使用净位移作为响应变量。基于男性和女性交配后行为可能不同的假设，我们寻找女性特有的迁徙行为，表明女性正在向筑巢区移动。获得的结果证实了我们的假设，当女性表现出明显的迁徙行为时，到达狼火山火山口内的一个小高原区域。火山北缘以下400米。此外，一旦进入破火山口,女性表现出更聚集的分布格局。获得的移动数据使加拉帕戈斯国家公园的护林员能够找到单个粉红色的鬣蜥巢，然后观察并收集该物种的第一批幼体。这项工作构成了对粉红色鬣蜥巢和新兴孵化鬣蜥进行专门研究的必要基线，这是朝着制定有效的先发计划迈出的重要一步。
