Ecological Diversity of Miocene Mammals of Pakistan

巴基斯坦中新世哺乳动物的生态多样性catherine Badgley， Thure Cerling, Anna K. Behrensmeyer, John C. barr年- 0125636摘要本合作项目评估了巴基斯坦中新世晚期（500万至1100万年前）哺乳动物对气候和植被变化的生态和进化响应。我们的国际研究小组对巴基斯坦北部的化石和沉积岩进行了超过25年的地质、古生物学和古生态学的实地研究，充分记录了巴基斯坦北部的化石和沉积岩。（Siwalik指的是过去2000万年喜马拉雅山上升所形成的河流沉积物。）迄今为止，对Siwalik沉积物和脊椎动物化石，特别是哺乳动物化石的研究，提供了关于河流系统、气候和植被变化、化石组合的保存属性和哺乳动物动物群的详细记录。这一记录是对新生代大陆生态系统的最好记录之一，它为评估与持续环境变化有关的哺乳动物物种和动物群的分类组成、物种形成、迁移、局部灭绝和生态属性的变化提供了机会。我们的项目首先包括为哺乳动物化石创建一个电子数据库（Siwalik物种数据库）。该数据库将包含生态学信息，基于标本的测量，包括每个物种的形态和同位素数据。接下来，我们将使用这些数据来测试三种模型，以了解哺乳动物群是如何随时间变化的。一个模型关注气候和植被变化对哺乳动物组成和生态属性的直接影响。第二个模型评估地理范围大、局部丰度高的物种是否主导了区系变化格局。第三个模型检验了这样一种假设，即几种超大型哺乳动物（大象大小）的到来，通过摄食和践踏改变了当地的栖息地，并导致了生态群落其他部分的变化。每个模型都对与环境变化相关的动物变化的时间和性质做出了一套独特的预测。这些预测将用数据库中收集的数据进行检验。Siwalik物种数据库将稳定Siwalik哺乳动物的分类和生态数据，并使这些数据可用于旧大陆历史的其他研究。对三种动物变化模型的测试将展示化石记录如何有助于群落生态学的模式和理论。

Ecological diversity of Miocene mammals of PakistanCatherine Badgley, Thure Cerling, Anna K. Behrensmeyer, John C. BarryEAR-0125663Abstract This collaborative project evaluates the ecological and evolutionary responses of mammals to changes in climate and vegetation during the late Miocene (5 to 11 million years ago), as known from the terrestrial record of Pakistan. Fossils and sedimentary rocks of northern Pakistan are well documented by the work of our international research team that has conducted over 25 years of field work on the geology, paleontology, and paleoecology of the Siwalik sequence. (Siwalik refers to fluvial sediments shed by the rising Himalayas over the last 20 million years.) Work to date on Siwalik sediments and vertebrate fossils, especially mammals, has provided a detailed record of changing fluvial systems, climate and vegetation, preservational attributes of fossil assemblages, and mammalian faunas. This record is one of the best documented continental ecosystems of the Cenozoic and now presents the opportunity to evaluate changes in taxonomic composition, speciation, immigration, local extinction, and ecological attributes of mammalian species and faunas in relation to sustained environmental change. Our project involves first the creation of an electronic database (the Siwalik species database) for fossil mammals. The database will contain ecologically informative, specimen-based measurements, including morphological and isotopic data for each species. Next, we will use this compilation of data to test three models of how mammalian faunas changed over time. One model focuses on the direct effects of changing climate and vegetation on the composition and ecological attributes of mammals. The second model evaluates whether or not species with large geographic ranges and high local abundance dominate the pattern of faunal change. The third model examines the hypothesis that the arrival of several species of extremely large mammals (the size of elephants) altered the local habitat through feeding and trampling and caused changes in the rest of the ecological community. Each model makes a unique set of predictions about the timing and nature of faunal change in relation to environmental change. These predictions will be tested with the data assembled in the database. The Siwalik species database will stabilize the taxonomic and ecological data for Siwalik mammals and make these data accessible for other studies of Old World history. Tests of the three models of faunal change will demonstrate how the fossil record contributes to patterns and theory in community ecology.