Restoring riparian habitats for benefits to biodiversity and human livelihoods: a systematic map protocol for riparian restoration approaches in the tropics

Background Riparian zones are vital transitional habitats that bridge the gap between terrestrial and aquatic ecosystems. They support elevated levels of biodiversity and provide an array of important regulatory and provisioning ecosystem services, of which, many are fundamentally important to human well-being, such as the maintenance of water quality and the mitigation of flood risk along waterways. Increasing anthropogenic pressures resulting from agricultural intensification, industry development and the expansion of infrastructure in tropical regions have led to the widespread degradation of riparian habitats resulting in biodiversity loss and decreased resilience to flooding and erosion. Considering climate change and its associated effects on freshwater systems, the need to build resilience and adaptive capacities is pertinent. This has prompted the need to protect existing riparian habitats and the implementation of solutions to restore these degraded habitats to recover their functional capacity. This systematic map will aim to identify and collate existing literature on approaches for riparian restoration implemented in tropical regions and identify what indicators have been used to measure outcomes for biodiversity and human well-being. The resulting collation of evidence will help to identify current knowledge gaps and inform the direction of future research. Methods To address the aims of this systematic map, a search of pre-identified bibliographic databases will be undertaken using a set string of search terms. In addition to this, a grey literature search will be conducted using Google Scholar and by searching for references using specialist websites. All literature that is gathered will be screened by title, abstract and full text using a two-phase screening process which adheres to a predetermined eligibility criteria. Data will then be coded from the collated group of articles using a pre-designed data coding sheet. Heterogeneity will likely be present in the data; therefore, studies will be grouped appropriately based on the restoration strategy implemented and, on the type of outcome measured. These will be presented as subgroups. A narrative synthesis of map findings will be produced, this will outline the distribution and frequency of restoration interventions , and outcomes measured, and will highlight evidence gaps to direct future research.