Looking to the past to conserve present-day biodiversity: using distributional information and ecological modelling

长期以来，物种保护的重点一直是防止人类造成的物种灭绝。因此，在过去的50年里，物种灭绝风险的变化是衡量保护成功与否的标准，主要的例子是世界自然保护联盟的物种红色名录。然而，最近有人呼吁同时关注物种的恢复，并制定评估其成就的指标。在生态保护界，这种观点的转变可以部分归因于认识到物种丰富度和分布的基线在人类世代之间发生了巨大变化，全球范围内可检测到的人类对生态系统的影响至少始于几千年前。对灭绝风险的评估通常只考虑物种在过去几十年的变化，而对恢复的评估则要考虑几百年到几千年的变化。这需要确定当人类首次成为影响一个物种的丰度和分布的主要因素时的基线状态。为了促进基线研究，保护古生物学网络（CPN）工作组的主要目标是开发和实施新的IUCN物种绿色状态框架。该框架考虑了相对于影响前基线的物种保护状况。将利用全球衍生的古生态和历史生态数据集来促进这些分布基线的估计。这项工作的一个关键方面将是为从业者提供一种容易接近的方法来确定他们感兴趣的物种的基线。CPN项目的目标是应用预测物种分布的方法来重建给定物种的过去范围。一般的方法是：1。识别可用于了解过去物种分布的数据集。变量的主要类别将是：>土地覆盖（如LUH2）>气候（如BioClim变量，CHELSA）>人类足迹（如ANTHROMES）>物种发生（如GBIF）>历史或考古物种的存在点。2 .利用当前数据（如气候和土地覆盖）和当前物种发生情况，建立物种生态位模型。使用具有预测变量的历史数据的模型来推断物种在过去的分布。使用物种发生的历史数据（如博物馆记录、化石数据、历史记录）来验证模型预测。重点是重建公元1500年至1750年的物种分布。最终目标是演示和验证工作流，并使该工作流广泛地为保护评估人员所访问。一个适当的起点是将上述方法应用于一个或几个物种，以证明其可行性，并作为找出困难的一种方法。最初的目标物种应涵盖一系列栖息地生态位（陆地、淡水和海洋）和空间尺度（从局部种群到全球分布）。另一个重要因素是，当某些元素缺失时，开发和验证替代工作流程（例如，存在当前事件，但不存在过去事件；存在相关/相关分类群的事件，但不存在焦点物种）。

Species conservation has long focused on preventing human-driven extinctions. Conservation success has therefore been measured using changes in species' extinction risk over the past 50 years, with the primary example being the IUCN Red List of Species. However, recently calls have been made for a parallel focus on species' recovery, and on developing metrics with which to assess its achievement. This shift in perspective within the conservation community can be partially attributed to the recognition that baselines of species' abundance and distribution have shifted dramatically across human generations, with globally detectable human impacts on ecosystems beginning at least several thousand years ago. Assessment of extinction risk generally only considers species' change over the past few decades, whereas assessment of recovery means considering change over centuries to millennia. This requires identifying the baseline status at the time when humans first became a major factor influencing the abundance and distribution of a species.In order to facilitate research on baselines, the primary aim of the Conservation Paleobiology Network (CPN) working group is the development and implementation of the new IUCN Green Status of Species framework. This framework considers the conservation status of species relative to a pre-impact baseline. Globally-derived palaeo-ecological and historical ecological datasets will be leveraged to facilitate estimation of these distributional baselines. A crucial aspect of this work will be to provide an easily accessible way for practitioners to determine baselines for their species of interest. The goal of the CPN project is to apply methods for predicting species distributions to reconstruct the past range of a given species. The general approach is:1. Identification of datasets that can be used to inform past species' distributions. The major categories of variables will be:> Land cover (e.g. LUH2)> Climate (e.g. BioClim variables, CHELSA)> Human footprint (e.g. ANTHROMES)> Species occurrences (e.g. GBIF)> Historical or Archaeological species' presence points.2. Model the ecological niche of the species' using current data (such as climate and land cover) and current species occurrences.3. Use the model with historical data on the predictor variables to extrapolate the species' distribution back in time.4. Use historical data on species occurrences (such as museum records, fossil data, historical accounts) to validate the model prediction. Priority will be on reconstructing species' distributions in the temporal range 1500 to 1750 CE.The ultimate goal is to demonstrate and validate a workflow, and to make this workflow widely accessible to conservation assessors. An appropriate starting point is to apply the above approach to one or few species as a demonstration of feasibility and as a way to figure out difficulties. Initial target species should cover a range of habitat niches (terrestrial, freshwater, and marine examples) and spatial scales (localised population to global distribution). Another important element will be to develop and validate alternate workflows when certain elements are missing (e.g. current occurrences exist, but not past occurrences; occurrences exist for related/associated taxa but not focal species).