Sánchez-Mercado Ada, Rodríguez-Clark Kathryn M, Miranda Jhonathan, Ferrer-Paris José Rafael, Coyle Brian, Toro Samuel, Cardozo-Urdaneta Arlene, Braun Michael J
Centro de Estudios Botánicos y Agroforestales Instituto Venezolano de Investigaciones Científicas (IVIC) Caracas Venezuela.
Centro de EcologíaI VIC Caracas Venezuela.
Ecol Evol. 2017 Dec 10;8(2):841-851. doi: 10.1002/ece3.3628. eCollection 2018 Jan.
Species distribution models (SDM) can be valuable for identifying key habitats for conservation management of threatened taxa, but anthropogenic habitat change can undermine SDM accuracy. We used data for the Red Siskin (), a critically endangered bird and ground truthing to examine anthropogenic habitat change as a source of SDM inaccuracy. We aimed to estimate: (1) the Red Siskin's historic distribution in Venezuela; (2) the portion of this historic distribution lost to vegetation degradation; and (3) the location of key habitats or areas with both, a high probability of historic occurrence and a low probability of vegetation degradation. We ground-truthed 191 locations and used expert opinion as well as landscape characteristics to classify species' habitat suitability as excellent, good, acceptable, or poor. We fit a Random Forest model (RF) and Enhanced Vegetation Index (EVI) time series to evaluate the accuracy and precision of the expert categorization of habitat suitability. We estimated the probability of historic occurrence by fitting a MaxLike model using 88 presence records (1960-2013) and data on forest cover and aridity index. Of the entire study area, 23% (20,696 km) had a historic probability of Red Siskin occurrence over 0.743. Furthermore, 85% of ground-truthed locations had substantial reductions in mean EVI, resulting in key habitats totaling just 976 km, in small blocks in the western and central regions. Decline in Area of Occupancy over 15 years was between 40% and 95%, corresponding to an extinction risk category between Vulnerable and Critically Endangered. Relating key habitats with other landscape features revealed significant risks and opportunities for proposed conservation interventions, including the fact that ongoing vegetation degradation could limit the establishment of reintroduced populations in eastern areas, while the conservation of remaining key habitats on private lands could be improved with biodiversity-friendly agri- and silviculture programs.
物种分布模型（SDM）对于识别受威胁分类群保护管理的关键栖息地可能很有价值，但人为栖息地变化会削弱SDM的准确性。我们使用了极度濒危鸟类红鹀的数据，并进行实地调查，以研究人为栖息地变化作为SDM不准确的一个来源。我们的目标是估计：（1）红鹀在委内瑞拉的历史分布；（2）因植被退化而丧失的这一历史分布的比例；（3）关键栖息地或兼具历史出现概率高和植被退化概率低的区域的位置。我们对191个地点进行了实地调查，并利用专家意见以及景观特征将物种栖息地适宜性分类为优、良、可接受或差。我们拟合了一个随机森林模型（RF）和增强植被指数（EVI）时间序列，以评估专家对栖息地适宜性分类的准确性和精确性。我们通过使用88个存在记录（1960 - 2013年）以及森林覆盖和干旱指数数据拟合一个MaxLike模型来估计历史出现概率。在整个研究区域中，23%（20,696平方公里）的区域红鹀历史出现概率超过0.743。此外，85%的实地调查地点平均EVI大幅下降，导致关键栖息地仅为976平方公里，分布在西部和中部地区的小块区域。15年间占用面积下降了40%至95%，对应于易危和极度濒危之间的灭绝风险类别。将关键栖息地与其他景观特征相关联，揭示了拟议保护干预措施的重大风险和机遇，包括持续的植被退化可能限制东部地区重新引入种群的建立，而通过有利于生物多样性的农业和林业计划可以改善私人土地上剩余关键栖息地的保护。
