Ramsay Jennifer, Sandom Christopher, Ings Thomas, Wheeler Helen C
School of Life Sciences, Anglia Ruskin University, East Road, Cambridge, CB1 1PT, UK.
School of Life Sciences and Sussex Sustainability Research Programme, University of Sussex, Brighton, BN1 9RH, UK.
Environ Evid. 2022 Apr 19;11(1):14. doi: 10.1186/s13750-022-00270-2.
In recent years there has been an increased focus on the role of large herbivores in ecosystem restoration and climate change mitigation. There are multiple processes by which large herbivores could potentially influence climate feedback and forcing effects, but the evidence has not yet been synthesised in a systematic and accessible format. Grazing, browsing, trampling, defecation, and seed dispersal by large herbivores can influence vegetation and soils in ways that may directly or indirectly contribute to climate change or mitigation. For example, changes in vegetation could impact wildfire regimes, carbon storage, and albedo, with ultimate impacts on climate. These processes may be influenced by herbivore species composition, density, and functional traits. The main aim of this systematic map is to synthesise the range of research on climate feedback and forcing effects from large herbivores (≥ 10 kg) in terrestrial ecosystems. We also aim to identify knowledge clusters and gaps in the research base, as well as assessing the potential for quantitative analyses.
A search of peer-reviewed and grey literature will be conducted using a range of bibliographic databases, search engines and websites. The search strategy will involve using a pre-defined search string with Boolean operators. All search results will be screened for relevance according to specific eligibility criteria. Screening will be conducted in two stages: all articles will initially be screened by title and abstract, then those that meet the eligibility criteria will be screened by full text. At both stages, articles will be excluded if they don't meet all eligibility criteria or if they meet any exclusion criteria. All articles included as eligible after full text screening will be coded. At each stage (of screening and coding) a proportion of articles will be processed independently by two reviewers to assess inter-reviewer reliability and resolve differences. The evidence will be presented in a searchable database with accompanying visual outputs. A narrative synthesis will be provided outlining the range and distribution of evidence, knowledge gaps and clusters, potential bias, and areas for further research.
近年来，大型食草动物在生态系统恢复和缓解气候变化中的作用受到了越来越多的关注。大型食草动物可能通过多种过程影响气候反馈和强迫效应，但相关证据尚未以系统且易于获取的形式进行综合。大型食草动物的放牧、啃食、践踏、排便和种子传播会以直接或间接促进气候变化或缓解气候变化的方式影响植被和土壤。例如，植被变化可能影响野火状况、碳储存和反照率，最终影响气候。这些过程可能受食草动物物种组成、密度和功能性状的影响。本系统综述的主要目的是综合陆地生态系统中大型食草动物（≥10千克）对气候反馈和强迫效应的一系列研究。我们还旨在识别研究基础中的知识集群和差距，并评估定量分析的潜力。
将使用一系列文献数据库、搜索引擎和网站对同行评审文献和灰色文献进行检索。检索策略将涉及使用带有布尔运算符的预定义检索词。所有检索结果将根据特定的纳入标准进行相关性筛选。筛选将分两个阶段进行：所有文章首先将通过标题和摘要进行筛选，然后对符合纳入标准的文章进行全文筛选。在两个阶段，如果文章不符合所有纳入标准或符合任何排除标准，将被排除。全文筛选后所有被纳入的合格文章都将进行编码。在筛选和编码的每个阶段，一部分文章将由两位评审员独立处理，以评估评审员间的可靠性并解决分歧。证据将呈现于一个可搜索的数据库中，并伴有可视化输出。将提供一篇叙述性综述，概述证据的范围和分布、知识差距和集群、潜在偏差以及进一步研究的领域。
