A coupled climate-vegetation-mammal-human model for simulating Late Quaternary megafaunal extinctions

用于模拟晚第四纪巨型动物灭绝的气候-植被-哺乳动物-人类耦合模型

基本信息

批准号：
NE/P002536/1
负责人：
Adrian Lister
金额：
$ 76.79万
依托单位：
Natural History Museum
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2016
资助国家：
英国
起止时间：
2016 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=NE%2FP002536%2F1
关键词：
coupled climate vegetation mammal human

项目摘要

The period 60,000-5,000 years ago saw the extinction of up to a thousand species of large vertebrates ('megafauna') across six continents. Understanding the cause of these extinctions is important for several reasons. It is the most recent substantial extinction event in the geological record; there is a background of detailed knowledge about environmental change against which to view the responses of the mammals; and humans are strongly implicated by many researchers as partial or exclusive causal agents. For all of these reasons, understanding the cause of the extinctions, and the reasons why some species survived while others did not, can provide a unique historical analogue for addressing the current biodiversity crisis. The two main contenders for the megafaunal extinction are vegetation change driven by climate, and hunting by humans, either separately or in combination. Although the extinction was worldwide, we will focus on Europe, northern Asia and North America as these areas have the best data on the distributions and extinction of the mammals. We will first develop computer-based simulations of local climatic conditions across the study area; for the first time climate changes will be modelled on a year-by-year basis over the past 40,000 years. Using this information we will model vegetation types across the entire area. When climate changed, vegetation changed, but our model will be crucially more realistic than previous ones in that we will allow for the lags in vegetational response as plant species expand slowly across large areas (e.g. trees may have taken 1500 years to arrive in northern Europe when climate warmed after a long cold spell). In addition, the model estimates not only the type of vegetation but its productivity, i.e. amount of growth each year, of crucial importance to herbivorous mammals. Many of the mammals that went extinct (such as the woolly mammoth and wooly rhinoceros) were grazing species adapted to the productive grasslands of the last glaciation, and the predators that depended on them. Many of those that survived were browsing (woodland) mammals or those of mixed habitats. We will develop, for both victims and survivors, a biological profile for each species including their body weight, reproductive rate, and preferred foods. These will be determined from living relatives and from direct evidence such as wear on fossil teeth that indicates diet. We will also establish their climatic tolerance from the range of climates they occupied in the past.Adding the mammal fauna to the modelled climate and vegetation, and running the computer model from 40,000 years ago up to the present, the effect of climate changes on the vegetation, and the effect of both on each mammal species, will be evident. Moreover, the model will include feedback from the feeding activities of the mammals to the structure of the vegetation itself. A final element in the model is the addition of variable levels of human hunting, the distribution of people being determined from known archaeological sites. Analysis of all the data will determine if climatic and vegetational change, with or without the addition of hunting, are sufficient to account for the extinction of some megafauna and survival of others. This will be determined by comparing model results with the known pattern of range changes and extinction based on the fossil record. The vegetation model that we develop would also allow prediction of likely responses to future climatic changes. Similarly, the climate simulations will be applicable to other processes (e.g. the changing extent of arctic permafrost). Our results will be directly relevant to various stakeholders, informing landscape management and biodiversity conservation strategies. We will ensure that they are communicated to such stakeholders, as well as to the scientific community and wider public.

在60,000 - 5,000年前的那个时期看到了六大大洲多达一千种大型脊椎动物（'Megafauna'）的灭绝。理解这些灭绝的原因很重要，原因有几个。这是地质记录中的最新灭绝事件。有关于环境变化的详细知识背景，以查看哺乳动物的反应；许多研究人员将人类与部分或独家因果药有关。由于所有这些原因，了解灭绝的原因，以及某些物种幸存而另一些物种未能生存的原因，可以为解决当前的生物多样性危机提供独特的历史类似物。大型巨型灭绝的两个主要竞争者是由气候驱动的植被变化，并分别或组合人类狩猎。尽管灭绝是在全球范围内的，但我们将专注于欧洲，北亚和北美，因为这些地区拥有有关哺乳动物分布和灭绝的最佳数据。我们将首先开发基于计算机的研究区域的当地气候状况的模拟；在过去的40，000年中，气候变化将首次逐年建模。使用此信息，我们将在整个区域建模植被类型。当气候变化时，植被发生了变化，但是我们的模型将比以前的模型更为现实，因为我们将允许植被反应的滞后，因为植物物种在大面积地区缓慢膨胀（例如，在经过长期的寒冷后气候变暖时，树木可能需要1500年才能到达北欧）。此外，该模型不仅估计植被的类型，而且估计其生产力，即每年的生长量，对草食性哺乳动物至关重要。许多灭绝的哺乳动物（例如羊毛猛mm和羊毛犀牛）都是放牧物种，适合于最后一次冰川的生产草原，以及依赖于它们的捕食者。许多幸存的人是浏览（林地）哺乳动物或混合栖息地的哺乳动物。我们将针对受害者和幸存者开发每个物种的生物学特征，包括其体重，生殖率和首选食物。这些将取决于活着的亲戚和直接证据，例如表明饮食的化石牙齿磨损。我们还将从过去占用的气候范围内建立他们的气候耐受性。将哺乳动物动物群添加到建模的气候和植被中，并从40，000年前到现在，直到现在，气候变化对植被的影响以及两种对每种哺乳动物物种的影响的影响都将是显而易见的。此外，该模型将包括从哺乳动物的喂养活动到植被本身结构的反馈。该模型中的最终要素是增加人类狩猎水平，从已知考古遗址确定的人的分布。对所有数据的分析将确定气候和植被变化是否在有或不增加狩猎的情况下是否足以说明某些Megafauna的灭绝和其他人的生存。这将通过将模型结果与基于化石记录的范围变化和消光的已知模式进行比较来确定。我们开发的植被模型还可以预测可能对未来气候变化的反应。同样，气候模拟将适用于其他过程（例如，北极多年冻土的变化范围）。我们的结果将与各种利益相关者直接相关，向景观管理和生物多样性保护策略提供信息。我们将确保将他们传达给此类利益相关者，以及科学界和更广泛的公众。