Universidad Nacional de Córdoba, Facultad de Ciencias Exactas, Físicas y Naturales, Centro de Zoología Aplicada and Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Instituto de Diversidad y Ecología Animal (IDEA), Córdoba, Argentina; Ecología para la Conservación del Gran Desierto, A.C, Hermosillo, C.P, 83174, Sonora, Mexico.
School of Natural Resources and the Environment, University of Arizona, Tucson, AZ, 85721, USA.
J Therm Biol. 2022 Feb;104:103192. doi: 10.1016/j.jtherbio.2022.103192. Epub 2022 Jan 22.
Tortoises of the genus Gopherus evolved in North America and have survived major environmental challenges in the past 40 million years. However, this genus now faces multiple anthropogenic threats, such as the introduction of invasive plant species. Buffelgrass (Cenchrus ciliaris) is considered one of the greatest threats to arid and tropical ecosystems, where gopher tortoises inhabit, because the grass displaces native flora and fauna. Modification of the environment as a result of this invasive plant portends an alteration of the available thermal landscape. The aim of this paper is twofold: 1) to evaluate the thermal quality of the primary habitat of Gopherus evgoodei (tropical deciduous forest [TDF], and 2) determine the potential thermal changes due to habitat modification by buffelgrass. First, we obtained data on body temperature of active tortoises in semi-captivity. Second, we measured the operative environmental temperature during 5 years at three sites south of Sonora, Mexico that support G. evgoodei: a) a pristine TDF (Conserved-TDF); b) a forest patch surrounded by introduced buffelgrass pasture (Partial-TDF); and c) an introduced buffelgrass pasture area (Buffel-Pasture). Our results demonstrate that the intact microhabitats within the TDF provide G. evgoodei with high thermal quality at both spatial and temporal scales. However modified habitat by buffelgrass had higher operative temperatures for G. evgoodei than TDF. The thermal quality of the sites disturbed with buffelgrass can exceed the thermal requirements of G. evgoodei by up to 25 °C. Finally, we discussed potential collateral effects of habitat modification by invasion by buffelgrass.
龟鳖目象龟属的龟在北美进化，并在过去的 4000 万年中幸存下来，经历了重大的环境挑战。然而，该属现在面临着多种人为威胁，例如引入入侵植物物种。水牛草（Cenchrus ciliaris）被认为是对干旱和热带生态系统的最大威胁之一，象龟栖息在这些生态系统中，因为这种草取代了当地的动植物。这种入侵植物对环境的改变预示着可用热景观的改变。本文的目的有两个：1）评估 Gopherus evgoodei 的主要栖息地（热带落叶林 [TDF] 的热质量，2）确定由于水牛草栖息地的改变而导致的潜在热变化。首先，我们在半圈养条件下获得了活动龟体温的数据。其次，我们在墨西哥索诺拉南部的三个地点测量了 5 年的环境操作温度，这些地点支持 G. evgoodei：a）原始的 TDF（Conserved-TDF）；b）被引入的水牛草牧场包围的森林斑块（Partial-TDF）；c）引入的水牛草牧场区（Buffel-Pasture）。我们的结果表明，TDF 内完整的微观生境为 G. evgoodei 在空间和时间尺度上提供了高质量的热环境。然而，水牛草改造的栖息地的操作温度比 TDF 更高。受水牛草干扰的地点的热质量可能比 G. evgoodei 的热需求高出 25°C。最后，我们讨论了水牛草入侵对栖息地改变的潜在附带影响。
