Ecological response of large herbivores to the late Quaternary climatic changes in northeast Iberian Peninsula refugium

伊比利亚半岛是欧洲南部地区之一，在第四纪晚期的气候变化中，人类和动物的占领持续存在。在这个项目中，我们的目的是调查，以现存的不同冷和暖的气候事件之间的ca。4万年前和1万年前的气候变化对大型食草动物的生态产生了影响，即红鹿（Cervus elaphus）和马（Equus sp.）在这个避难所。我们打算利用它们骨胶原和牙釉质中稳定同位素的含量来重建它们的饮食、栖息地和环境的一些参数。我们考虑了欧洲的三个关键时期，这是1）海因里希事件4（约。40 kyr cal BP），2）末次冰期最大值附近（27-23 kyr cal BP），3）海因里希事件1（约。15.6至9.8 kyr cal BP）。这些关键时间范围中的每一个都对应着气候条件的重大变化，这些变化引发了欧洲人类和动物种群的变化。所研究的材料包括骨骼遗骸的红鹿（67骨和40颗牙齿）和马（53骨和30颗牙齿）来自七个考古遗址的中等海拔（170至760米）。来自成熟个体的骨胶原的稳定同位素（碳-13和氮-15）由于不断的骨重建而提供了成人寿命的长期记录。碳-13通知饲料的喜好，但也反映了湿度和栖息地的封闭条件。氮-15是饮食（放牧与浏览）和环境的指标，如当地温度和湿度条件。饮食和环境的影响可以通过检查牙齿磨损的强度来解开，牙齿磨损的强度主要取决于草与树叶的消耗。通过对牙齿釉质上的氧-18和碳-13的连续分析，可以获得温度和栖息地的短时间季节记录，牙齿形成后牙釉质不会重塑。第三磨牙的同位素序列应该反映出红鹿个体生命的第二个冬天，以及马个体生命的第二年和第四年之间的一个夏天和一个冬天。该项目的结果将有助于测试两种情况：1）由于其生态灵活性，食草动物通过改变栖息地和饮食来适应不断变化的环境，或2）气候条件变化的局部缓冲，使物种能够在生态没有显着变化的情况下持续存在。最终，了解红鹿和马如何科普过去的气候变化（栖息地，饮食适应）可以帮助我们预测这些物种对现在和未来环境变化的耐受性。

The Iberian Peninsula is one of the southern regions in Europe that saw the persistence of human and animal occupation over the climatic changes of the late Quaternary. In this project, we aim at investigating to which extant the different colder and warmer climatic episodes between ca. 40,000 and 10,000 years ago have impacted the ecology of the large herbivores, namely red deer (Cervus elaphus) and horse (Equus sp.) in this refuge area. We intend to use the amounts of stable isotopes in their bone collagen and tooth enamel to reconstruct their diet, habitat and some parameters of their environment. We consider three key periods in Europe, which are 1) around the Heinrich event 4 (ca. 40 kyr cal BP), 2) around the Last Glacial Maximum (27-23 kyr cal BP), and 3) after the Heinrich Event 1 (ca. 15.6 to 9.8 kyr cal BP). Each of these key time ranges corresponds to a major change in the climatic conditions that have triggered human and animal population turn over in Europe. The studied material consists of skeletal remains of red deer (67 bones and 40 teeth) and horse (53 bones and 30 teeth) coming from seven archaeological sites of mid-range altitudes (170 to 760 m asl). The stable isotopes (carbon-13 and nitrogen-15) of bone collagen from mature individuals deliver a long-term record of adult lifetime as a result of the constant bone remodelling. Carbon-13 informs on the forage preferences but also reflects conditions of humidity and closure of the habitat. Nitrogen-15 is an indicator of the diet (grazing versus browsing) and of the environment, such as the local temperature and conditions of humidity. The dietary and environmental influences can be disentangled by examining the intensity of the dental wear that depends mainly on the consumption of grasses versus leaves. Short time seasonal record of temperature and habitat can be obtained by the sequential analysis of oxygen-18 and carbon-13 over the tooth enamel, which does not remodel after the formation of the tooth. The isotopic sequence of the third molar should reflect the second winter of the life of the individual for the red deer, and one summer and one winter between the second and fourth year of the individual life of the horse. The results of this project will contribute to test two scenarios: 1) the adaptation of the herbivores to a changing environment through changes in habitat and diet thanks to their ecological flexibility or 2) the local buffering of the variation in climatic conditions allowing the species to persist without a significant change of their ecology. Ultimately, understanding how red deer and horse could cope with climatic changes (habitat, diet adaptation) in the past can help us to predict how tolerant will be these species to present-day and future environmental changes.