What are the impacts of manipulating grazing and browsing by ungulates on plants and invertebrates in temperate and boreal forests? A systematic review protocol

Abstract

Background: Livestock grazing and 'overabundance' of large wild herbivores in forested areas have long been perceived as conflicting with the aims of both silviculture and forest conservation; however, certain kinds of herbivory can help to maintain habitat values in forest ecosystems. Management of grazing/browsing in protected forests can, therefore, be a critical tool for biodiversity conservation. However, it is not clear what impacts of wild ungulates or livestock are tolerable or desirable in forests set aside for conservation or restoration. The primary aim of the proposed systematic review is to clarify how the diversity of plants and invertebrates is affected by manipulation of the grazing/ browsing pressure by livestock or wild ungulates. The ultimate purpose of the review is to investigate whether such manipulation is useful as a means of conserving or restoring biodiversity in forest set-asides. Methods:The review will examine primary field studies of how fencing or other kinds of manipulation of the grazing/browsing pressure by livestock or wild ungulates affects plants or invertebrates. We will consider studies made in boreal or temperate forests anywhere in the world, incorporating investigations made not only in protected areas but also in stands under commercial management. Non-intervention or alternative levels of grazing pressure will be used as comparators. Relevant outcomes include abundance, diversity and composition of plants and invertebrates, tree regeneration, and performance of focal/target species. Relevant studies will mainly be selected from a recent systematic map of the evidence on biodiversity impacts of active management in forest set-asides. A search update will be made with a subset of the search terms used for the systematic map. Searches for additional literature will be made in bibliographies of existing reviews. Relevant studies will be subject to critical appraisal and categorised as having high, medium or low susceptibility to bias. Studies with high susceptibility to bias will be excluded from the review. Useful outcomes and data on interventions and other potential effect modifiers will be extracted from included articles. A narrative synthesis will describe the quality and findings of all studies in the review. Where studies report similar outcomes, meta-analysis will be performed.

Manipulating ungulate herbivory in temperate and boreal forests: effects on vegetation and invertebrates. A systematic review

“…The design of this systematic review was established in detail in a peer-reviewed protocol [35]. It follows the guidelines for systematic reviews and evidence synthesis issued by the Collaboration for Environmental Evidence [36].…”

“…The topic was also considered important for stakeholders in Sweden and beyond. We subsequently published a protocol for this systematic review [35], focusing on wild ungulate and livestock impacts on vegetation and invertebrates in temperate and boreal forests. The present article reports the findings of the review.…”

What is the effect of prescribed burning in temperate and boreal forest on biodiversity, beyond tree regeneration, pyrophilous and saproxylic species? A systematic review protocol

“…The selection of topics was also based on their significance for managers of forest reserves and other stakeholders, and on their relevance to Swedish forests, following stakeholder engagement. Two of the suggested systematic reviews are currently in progress [13,14].…”

“…The direct impact of fire on tree regeneration, pyrophilous and saproxylic species have been well studied, and one of the systematic reviews in progress is investigating the effect of dead-wood manipulation (e.g. through burning) on biodiversity in forests [13]. Furthermore, one recent systematic review investigated the impact of restoration burning on tree regeneration in boreal forests [15].…”

“…We outline specific steps taken in each database to adapt this string to the specific search facility whilst also making use of the existing systematic map database (Bernes et al [14]). …”