Conservation of species reliant on ephemeral resources can be especially challenging in the face of a changing climate. Western spadefoots (Spea hammondii) are small burrowing anurans that breed in ephemeral pools, but adults spend the majority of their lives underground in adjacent terrestrial habitat. Western spadefoots are of conservation concern throughout their range because of habitat loss, but little is known about the activity patterns and ecology of their terrestrial life stage. We conducted a radio-telemetry study of adult western spadefoots at 2 sites in southern California, USA, from December 2018 to November 2019 to characterize their survival, behavior, and movements from breeding through aestivation to refine conservation and management for the species. Western spadefoot survival varied seasonally, with risk of mortality higher in the active season than during aestivation. The probability of movement between successive observations was higher during the winter and spring and when atmospheric moisture was high and soil water content at 10-cm depth was low. The amount of rain between observations had the strongest effect on the probability of movement between observations; for every 20 mm of rainfall between observations, western spadefoots were 2.4 times more likely to move. When movements occurred, movement rates were highest when both relative humidity and soil water content at 10-cm depth were high. The conditions under which western spadefoots were likely active on the surface, likely to have moved, and moved at the highest rates are conditions that reduce the risk of desiccation of surface-active spadefoots. Western spadefoot home range areas varied between study sites and were mostly <1 ha, although 1 individual's home range area was >6 ha. Western spadefoots rapidly dispersed from the breeding pools, and asymptotic distances from the breeding pool were generally reached by June. The asymptotic distance from the breeding pool varied between sites, with the 95th percentile of the posterior predictive distribution reaching 486 m at 1 site and 187 m at the other. Western spadefoots did not select most habitat components disproportionately to their availability, but at Crystal Cove State Park, they avoided most evaluated vegetation types (graminoids, forbs, and shrubs). Spatial variation was evident in most evaluated western spadefoot behaviors; context-dependent behavior suggests that site-specific management is likely necessary for western spadefoots. Furthermore, comparison with an earlier study of western spadefoots at Crystal Cove State Park indicated substantial temporal variation in western spadefoot behavior. Therefore, basing management decisions on short-term studies might fail to meet conservation objectives. Better understanding the influences of spatial context and climatic variation on western spadefoot behavior will improve conservation efforts for this species. © 2021 This article is a U.S. Government work and is in the public domain in the USA. The Journal of Wildlife Management published by Wiley Periodicals LLC on behalf of The Wildlife Society.

中文翻译：

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西部铲足陆生生态时空变化的保护意义

面对不断变化的气候，保护依赖于短暂资源的物种尤其具有挑战性。西部铲足（Spea hammondii）) 是在短暂的水池中繁殖的小型穴居无尾目鱼，但成年人的大部分时间都在地下相邻的陆地栖息地中度过。由于栖息地丧失，西部铲足在其整个范围内都受到保护，但对其陆地生活阶段的活动模式和生态知之甚少。我们于 2018 年 12 月至 2019 年 11 月在美国南加州的 2 个地点对成年西部黑鲀进行了无线电遥测研究，以描述它们从繁殖到夏眠的生存、行为和运动，以完善对该物种的保护和管理。西方铲足的存活率随季节变化，活跃季节的死亡风险高于夏眠期间。在冬季和春季，当大气湿度较高且 10 厘米深度的土壤含水量较低时，连续观测之间的移动概率较高。观测之间的降雨量对观测之间移动的概率影响最大；在两次观测之间，每降雨 20 毫米，西部铲足的移动可能性就增加 2.4 倍。当发生运动时，当 10 厘米深度的相对湿度和土壤含水量都高时，运动速率最高。西部铲足可能在地表活跃、可能已经移动并以最高速率移动的条件是降低表面活跃铲足干燥风险的条件。西部铲足的栖息地范围因研究地点而异，大部分小于 1 公顷，尽管 1 个人的家园面积大于 6 公顷。西部黑鲀迅速从繁殖池中散去，一般在6月份到达繁殖池的渐近距离。距繁殖池的渐近距离因站点而异，后验预测分布的第 95 个百分位数在一个站点达到 486 m，在另一个站点达到 187 m。西部铲足并没有选择与其可用性不成比例的大多数栖息地成分，但在水晶湾州立公园，它们避免了大多数评估过的植被类型（禾本科、杂草和灌木）。在大多数评估的西方铲足行为中，空间变化很明显；依赖环境的行为表明，特定地点的管理可能对西方铲足来说是必要的。此外，与早先在水晶湾州立公园对西部铲足的研究进行比较，表明西部铲足行为的显着时间变化。因此，基于短期研究的管理决策可能无法满足保护目标。更好地了解空间背景和气候变化对西方黑鲀行为的影响将改善对该物种的保护工作。© 2021 本文是美国政府的作品，在美国属于公共领域。这 更好地了解空间背景和气候变化对西方黑鲀行为的影响将改善对该物种的保护工作。© 2021 本文是美国政府的作品，在美国属于公共领域。这 更好地了解空间背景和气候变化对西方黑鲀行为的影响将改善对该物种的保护工作。© 2021 本文是美国政府的作品，在美国属于公共领域。这由 Wiley Periodicals LLC 代表野生动物协会出版的《野生动物管理杂志》。