Rej Julie E, Joyner T Andrew
Department of Wildlife Ecology, The Wilds, Cumberland, OH, USA.
Department of Geosciences, East Tennessee State University, Johnson City, TN, USA.
PeerJ. 2018 Dec 17;6:e6128. doi: 10.7717/peerj.6128. eCollection 2018.
As the climate warms, many species of reptiles are at risk of habitat loss and ultimately extinction. Locations of suitable habitat in the past, present, and future were modeled for several lizard species using MaxEnt, incorporating climatic variables related to temperature and precipitation. In this study, we predict where there is currently suitable habitat for the genus and potential shifts in habitat suitability in the past and future.
Georeferenced occurrence records were obtained from the Global Biodiversity Information Facility, climate variables (describing temperature and precipitation) were obtained from WorldClim, and a vegetation index was obtained from AVHRR satellite data. Matching climate variables were downloaded for three different past time periods (mid-Holocene, Last Glacial Maximum, and Last Interglacial) and two different future projections representative concentration pathways (RCPs 2.6 and 8.5). MaxEnt produced accuracy metrics, response curves, and probability surfaces. For each species, parameters were adjusted for the best possible output that was biologically informative.
Model results predicted that in the past, there was little suitable habitat for and within the areas of their current range. Past areas of suitable habitat for were predicted to be similar to the current prediction. and were predicted to have had a more expansive range of suitable habitat in the past, which has reduced over time. was predicted to have less suitable habitat in the past when examining the region of their known occurrence; however, there was predicted growth in suitable habitat in Western Australia. Both 2070 models predict a similar distribution of habitat; however, the model produced using the 2070 RCP 8.5 climate change projection showed a larger change, both in areas of suitable habitat gain and loss. In the future, and might gain suitable habitat, while the other four species could possibly suffer habitat loss.
Based on the model results, and had minimal areas of suitable habitat during the Last Glacial Maximum, possibly due to changes in tolerance or data/model limitations, especially since genetic analyses for these species suggest a much earlier emergence. The predicted late Quaternary habitat results for all species of are conservative and should be compared to the fossil record which is not possible at the moment due to the current inability to identify fossil to the species level. and future models predict substantial habitat loss. could potentially be considered vulnerable in the present since it already has a restricted range, and a conservation plan may need to be considered.
随着气候变暖，许多爬行动物种面临栖息地丧失并最终灭绝的风险。利用最大熵模型（MaxEnt），结合与温度和降水相关的气候变量，对几种蜥蜴物种过去、现在和未来的适宜栖息地位置进行了建模。在本研究中，我们预测了目前该属适宜栖息地的位置以及过去和未来栖息地适宜性的潜在变化。
地理参考出现记录来自全球生物多样性信息设施，气候变量（描述温度和降水）来自世界气候数据库（WorldClim），植被指数来自高级甚高分辨率辐射计（AVHRR）卫星数据。下载了三个不同过去时间段（全新世中期、末次盛冰期和末次间冰期）以及两个不同未来代表性浓度路径（RCPs 2.6和8.5）的匹配气候变量。最大熵模型生成了准确性指标、响应曲线和概率曲面。对于每个物种，对参数进行了调整以获得具有生物学信息的最佳可能输出。
模型结果预测，过去，在其当前分布范围内，该属的适宜栖息地很少。预测过去该属适宜栖息地的区域与当前预测相似。预测该属的两个物种过去适宜栖息地范围更广，但随着时间推移已缩小。在研究其已知出现区域时，预测过去该属的另一个物种适宜栖息地较少；然而，预计西澳大利亚的适宜栖息地会增加。两个2070年的模型预测的栖息地分布相似；然而，使用2070年RCP 8.5气候变化预测生成的模型显示，在适宜栖息地增加和减少的区域都有更大变化。未来，该属的两个物种可能会获得适宜栖息地，而其他四个物种可能会遭受栖息地丧失。
根据模型结果，在末次盛冰期，该属的两个物种适宜栖息地面积最小，这可能是由于耐受性变化或数据/模型限制，特别是因为对这些物种的遗传分析表明它们出现得更早。所有该属物种预测的晚第四纪栖息地结果较为保守，应与化石记录进行比较，但由于目前无法将化石鉴定到物种水平，目前尚无法做到。该属的两个物种未来模型预测会有大量栖息地丧失。由于其分布范围已经受限，该属的另一个物种目前可能被认为易危，可能需要考虑制定保护计划。
