In search of forage: predicting dynamic habitats of Mongolian gazelles using satellite-based estimates of vegetation productivity
In search of forage: predicting dynamic habitats of Mongolian gazelles using satellite-based estimates of vegetation productivity
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DOI：
10.1111/j.1365-2664.2007.01371.x
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发表时间：
2008-04-01
影响因子：
5.7
通讯作者：
Leimgruber, Peter
中科院分区：
文献类型：
--
作者：
Mueller, Thomas;Olson, Kirk A.;Leimgruber, Peter
1.栖息地适宜性的时间变化具有重要的保护和生态意义。在草原上，资源可利用性的变化可以发生在广阔的空间尺度上，并扩大有蹄类动物种群的面积需求，这增加了它们对栖息地丧失和破碎化的脆弱性。理解和预测这些动态，虽然关键，但迄今为止很少受到关注。研究了蒙古东部草原原羚（Procapra gutturosa Pallas）的栖息地动态。利用卫星影像的归一化植被指数（NDVI）数据，定量分析了瞪羚在四个不同时间段的分布，并追踪了其初级生产力.二阶逻辑模型表明，植被指数是一个有效的预测瞪羚的存在。我们用来自瞪羚遥测研究的独立数据测试了该模型的预测能力：85%的迁移都在预测区域内。瞪羚更喜欢中等范围的植被生产力，可能面临质量数量的权衡，即低NDVI的地区受到低摄食率的限制，而高NDVI的地区受到成熟牧草消化率低的限制。瞪羚栖息地面积的时空变化较大。在所有调查期间，只有15%的研究区域一直是瞪羚的栖息地，这表明瞪羚需要在广阔的区域寻找食物。只有1%的瞪羚栖息地始终位于保护区内。草原生境的变异性往往导致有蹄类动物的面积需求，从而阻碍了在单一保护区内的有效保护。它们需要生态系统层面的管理计划，但为这些计划提供信息的动态栖息地预测很难实施，而且往往无法获得。我们表明，卫星估计的植被生产力可以成功地用于生成动态的栖息地模型，在景观高度可变的资源，并证明了中间的NDVI值是至关重要的预测蒙古瞪羚的发生。
1. Temporal variability in habitat suitability has important conservation and ecological implications. In grasslands, changes in resource availability can occur at broad spatial scales and enlarge area requirements of ungulate populations, which increases their vulnerability to habitat loss and fragmentation. Understanding and predicting these dynamics, although critical, has received little attention so far.2. We investigated habitat dynamics for Mongolian gazelles (Procapra gutturosa Pallas) in the eastern steppes of Mongolia. We quantified the distribution of gazelles at four different time periods and tracked primary productivity using Normalized Difference Vegetation Index (NDVI) data from satellite imagery.3. A second-order logistic model showed that NDVI was an efficient predictor of gazelle presence. We tested the predictive power of the model with independent data from a gazelle telemetry study: 85% of all relocations were found within the predicted area.4. Gazelles preferred an intermediate range of vegetation productivity, presumably facing quality quantity trade-offs where areas with low NDVI are limited by low ingestion rates, and areas with high NDVI are limited by the low digestibility of mature forage.5. Spatiotemporal variation of gazelle habitat areas was high. Only 15% of the study area was consistently gazelle habitat throughout all survey periods, indicating that gazelles need to range over vast areas in search of food. Only 1% of the gazelle habitats were consistently located inside protected areas.Synthesis and applications. Habitat variability in grasslands often leads to area requirements of ungulates that prevent effective conservation within single protected areas. They require landscape-level management plans, but dynamic habitat predictions to inform such plans are difficult to implement and are often unavailable. We showed that satellite estimates of vegetation productivity can be used successfully to generate dynamic habitat models in landscapes with highly variable resources, and demonstrated that intermediate NDVI values were critical to predict occurrence of Mongolian gazelles.