Lehnen Sarah E, Sternberg Mitch A, Swarts Hilary M, Young John H, Hanley Victoria, Kline Richard J
U.S. Fish and Wildlife Service Albuquerque New Mexico USA.
South Texas Refuge Complex United States Fish and Wildlife Service Alamo Texas USA.
Ecol Evol. 2024 Dec 23;14(12):e70703. doi: 10.1002/ece3.70703. eCollection 2024 Dec.
In an environment increasingly dominated by roads, wildlife crossing structures (WCS) have been installed to decrease wildlife mortality and improve habitat linkages. In South Texas, vehicle collisions have been a major mortality source for the endangered ocelot (). To mitigate threats to this species, eight WCS, along with associated fencing, were strategically placed along Farm-to-Market Road 106 (FM106), which passes through ocelot habitat. We assessed the rate of on-roadway crossings and WCS use by GPS-collared animals before, during, and after WCS installation using camera traps to verify WCS use. Because of the rarity of ocelots in this region, we supplemented ocelot data with data from bobcats (), a similarly sized felid with slightly more general habitat preferences. Thirty-five animals, 30 bobcats, and 5 ocelots were tracked using GPS collars between 2013 and 2021. We observed a decline in the total number of crossings and on-roadway crossings of FM106 for both ocelots and bobcats over the duration of the study, despite controlling for factors such as an individual animal's proximity to FM106. There were 37 documented crossings using WCS by GPS-marked bobcats while their collars were active. However, the rate of on-roadway crossings during the post-construction period was still higher than the WCS use rate for both species. Animals were more likely to make on-roadway crossings during nighttime especially during unusually bright nights. While controlling for other factors, both species moved more quickly when making on-roadway crossings compared to WCS crossings or noncrossing intervals but moved more slowly when traffic levels were higher than expected for that time of day. Animals may take years to acclimate to the presence of WCS, suggesting that the use of these structures may increase over time. Additional fencing could further help limit high-risk road encounters by ocelots in this region.
在一个道路日益占据主导地位的环境中，已安装了野生动物通道结构（WCS）以降低野生动物死亡率并改善栖息地连通性。在南德克萨斯州，车辆碰撞一直是濒危豹猫的主要死亡原因。为了减轻对该物种的威胁，沿着穿过豹猫栖息地的106号农场到市场路（FM106）战略性地设置了8个WCS以及相关围栏。我们使用相机陷阱来验证WCS的使用情况，评估了在WCS安装之前、期间和之后佩戴GPS项圈的动物在道路上的穿越率和对WCS的使用率。由于该地区豹猫数量稀少，我们用山猫的数据补充了豹猫的数据，山猫是一种体型相似、栖息地偏好略为广泛的猫科动物。2013年至2021年期间，使用GPS项圈追踪了35只动物，其中30只山猫和5只豹猫。尽管控制了个体动物与FM106的距离等因素，但在研究期间，我们观察到豹猫和山猫在FM106上的总穿越次数和道路上的穿越次数均有所下降。有记录显示，佩戴GPS项圈的山猫在项圈活跃期间通过WCS进行了37次穿越。然而，施工后时期道路上的穿越率仍然高于这两个物种对WCS的使用率。动物尤其在异常明亮的夜晚更有可能在夜间进行道路穿越。在控制其他因素的情况下，与通过WCS穿越或非穿越时段相比，这两个物种在进行道路穿越时移动速度更快，但在交通流量高于当日预期水平时移动速度更慢。动物可能需要数年时间来适应WCS的存在，这表明随着时间的推移，对这些结构的使用可能会增加。额外的围栏可以进一步帮助减少该地区豹猫与高风险道路的接触。
