Ecological 'Tipping Points'? - How invasion of a potential canopy dominant affects landscape-scale ecosystem patterns

生态“临界点”？

• 批准号: NE/I011234/1
• 负责人: Brian Huntley
• 金额: $ 52.03万
• 依托单位: Durham University
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2012
• 资助国家: 英国
• 起止时间: 2012 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FI011234%2F1
• 关键词: Ecological; Tipping; Points; How; invasion

When climatic conditions change by a relatively large amount and relatively rapidly, as they are projected to do this century, species' principal response is to adjust their geographical distributions so that they continue to occupy areas with suitable conditions. As a result, species invade regions and landscapes where they previously were absent. In the case of species with the potential to be ecosystem dominants (e.g. trees that can dominate forest canopies), such invasions are likely to lead to marked changes in the ecosystems of the invaded area. Most landscapes support a range of ecosystems occupying areas differing in environmental conditions because of the relief of the landscape or the presence of different substrates for soil development. Such heterogeneity contributes to the ability of a landscape to support a range of species, biodiversity being higher in more heterogeneous landscapes. This heterogeneity also enables a wider range of species to move through the landscape as they respond to climatic changes. More homogeneous landscapes, or those where some habitat types have been lost, act as barriers to the movement of species and thus limit their ability to adapt to climatic change. Reliable projections are needed of how invasions by potential ecosystem dominants may affect ecosystem patterns and landscape heterogeneity. Such projections will inform the development of landscape management plans and biodiversity conservation strategies that together will maximise species' opportunities to adapt to climatic changes. We will collect data documenting the impacts of a past invasion on ecosystem patterns in three landscapes. We will apply the techniques of palaeoecology, principally pollen analysis and radiocarbon dating, to sediments that have accumulated in small basins in the landscapes since the end of the last glacial stage. By examining a series of such small basins in each landscape, as well as one larger basin in each case, we will obtain records of the changing composition of individual stands of vegetation, as well as records of the shifting regional vegetation composition. Together, these data will allow us to reconstruct ecosystem patterns on the landscapes through time. We will focus our attention on the invasion of Scots Pine into the Western Highlands of Scotland between about 8800 and 5800 years ago. Prior to this invasion the forests of this region generally had mixed canopies of Oak and Elm, with a Hazel understorey. Some stands of such mixed woodland persist, but Pine now dominates most of the remaining forests. The data we will collect will allow us to determine which parts of the landscape Pine invaded and how its invasion impacted upon ecosystem patterns and overall landscape heterogeneity. We will also use a state-of-the-art vegetation model to simulate the Pine invasion. This model uses as inputs, amongst other things, simulations of climatic conditions during the period when the invasion took place. We will compare simulated changes in ecosystem character and patterns on the landscapes associated with the invasion with patterns reconstructed from the palaeovegetation data. This will enable us to evaluate the model's ability reliably to simulate the consequences of such an invasion. This is important because such models provide one of the few tools available to project the potential consequences of invasions arising from species' responses to anthropogenic climatic change. In order to illustrate its potential for such applications, we will apply the model to simulate one such potential future invasion of a canopy dominant tree into these landscapes. Our results will be of direct relevance to various stakeholders, informing the development of landscape management and biodiversity conservation strategies. We will ensure that they are communicated to such stakeholders, as well as to the scientific community and to the wider public.

当气候条件发生相对较大和相对较快的变化时，正如本世纪预计的那样，物种的主要反应是调整它们的地理分布，以便它们继续占据条件适宜的地区。结果，物种入侵了它们以前不存在的地区和景观。对于有可能成为生态系统优势的物种（例如，可以支配森林冠层的树木），这种入侵很可能导致入侵地区的生态系统发生显著变化。大多数景观支持一系列生态系统，这些生态系统由于景观的起伏或土壤发育的不同基质的存在而占据不同的环境条件。这种异质性有助于景观支持一系列物种的能力，多样性在异质性更强的景观中更高。这种异质性也使更广泛的物种能够在应对气候变化时在景观中移动。更同质的景观，或者一些栖息地类型已经消失的景观，成为物种迁移的障碍，从而限制了它们适应气候变化的能力。需要对潜在生态系统优势入侵如何影响生态系统格局和景观异质性进行可靠的预测。这些预测将为景观管理计划和生物多样性保护战略的制定提供信息，它们共同将使物种适应气候变化的机会最大化。我们将收集记录过去入侵对三种景观生态系统模式影响的数据。我们将应用古生态学技术，主要是花粉分析和放射性碳定年，来研究自末次冰期结束以来在景观中的小盆地中积累的沉积物。通过在每个景观中考察一系列这样的小盆地，以及在每个景观中考察一个更大的盆地，我们将获得植被单个林分组成变化的记录，以及区域植被组成变化的记录。总之，这些数据将使我们能够随着时间的推移重建景观上的生态系统模式。我们将把注意力集中在大约8800到5800年前苏格兰松入侵苏格兰西部高地的事件上。在这次入侵之前，这个地区的森林通常是橡树和榆树的混合树冠，下面是榛树。这种混合林地的一些林分仍然存在，但松树现在主导了大部分剩余的森林。我们将收集的数据将使我们能够确定松树入侵的景观部分以及它的入侵如何影响生态系统模式和整体景观异质性。我们还将使用最先进的植被模型来模拟松树的入侵。该模型将入侵发生时的气候条件模拟作为输入。我们将比较与入侵相关的生态系统特征和景观模式的模拟变化与古植被数据重建的模式。这将使我们能够可靠地评估模型模拟这种入侵后果的能力。这一点很重要，因为这些模型提供了为数不多的工具之一，可以用来预测由于物种对人为气候变化的反应而引起的入侵的潜在后果。为了说明其在此类应用中的潜力，我们将应用该模型来模拟未来冠层优势树对这些景观的潜在入侵。我们的研究结果将与各种利益相关者直接相关，为景观管理和生物多样性保护策略的发展提供信息。我们将确保向这些利益攸关方以及科学界和更广泛的公众传达这些建议。

项目成果

Holocene expansion of the Caledonian pinewoods: spatial and temporal patterns at regional and landscape scales

喀里多尼亚松林的全新世扩张：区域和景观尺度的时空格局

• DOI: 10.1080/17550874.2021.1984601
• 发表时间: 2021
• 期刊: Plant Ecology & Diversity
• 影响因子: 1.5
• 作者: Huntley B

Joint palaeoclimate reconstruction from pollen data via forward models and climate histories

通过正演模型和气候历史从花粉数据联合重建古气候

• DOI: 10.1016/j.quascirev.2016.09.007
• 发表时间: 2016
• 期刊: Quaternary Science Reviews
• 影响因子: 4
• 作者: Parnell A

Frequency selection in paleoclimate time series: A model-based approach incorporating possible time uncertainty

古气候时间序列中的频率选择：基于模型的方法，考虑了可能的时间不确定性

• DOI: 10.1002/env.2492
• 发表时间: 2018
• 期刊: Environmetrics
• 影响因子: 1.7
• 作者: Franke P

Bayesian Inference for Palaeoclimate with time Uncertainty and Stochastic Volatility

古气候随时间不确定性和随机波动的贝叶斯推断

• DOI: 10.1111/rssc.12065
• 发表时间: 2015
• 期刊: Applied Statistics
• 作者: Parnell A

Climatic Disequilibrium Threatens Conservation Priority Forests

气候不平衡威胁着​​优先森林保护

• DOI: 10.1111/conl.12349
• 发表时间: 2017
• 期刊: Conservation Letters
• 影响因子: 8.5
• 作者: Huntley B