Activity-pressure-habitat linkage matrix: Identifying impact chains to assess impact risk to tropical marine ecosystems from human activities in four Southeast Asian case studies Version 1.0

Society relies on intact marine ecosystems for ecosystem services such as nutrition, livelihoods, health, and wellbeing. Yet, to obtain these benefits, we carry out activities, introducing pressures to ecosystems, damaging and degrading habitats and reducing their capacity to optimally provide ecosystem services. Biodiversity and ecosystem services are consequently being lost globally but impact chains from these activities are poorly understood, especially in tropical marine ecosystems. We identified for the first time impact chains linking activities with pressures they introduce in five tropical coastal and marine habitats, specifically through application in four Southeast Asian case study sites. Using expert elicitation based on existing evidence, we weighted each impact chain according to pressure extent, frequency and persistence, and habitat resistance and resilience. This dataset consists of a series of matrices linking human activities, the pressures they introduce, and the habitats they interact with, for four Southeast Asian case study sites. There are five tabs in the file that describe the elements of matrices. There are eight tabs with the main data matrices, two matrices per case study. The first matrix per case study contains the ‘links’, which indicate where an association was identified between an activity-pressure combination and a habitat in a given case study (the impact chains). Cell colour indicates a confidence score for each of these links. The second matrix per case study gives an impact risk weighting for each activity-pressure-habitat (impact chain) combination according to five criteria. These data can be used to assess ecological impact risk in these habitats and case studies. 

Methods
We studied four marine reserves and protected areas across four countries in Southeast Asia. These were: Cu Lao Cham – Hoi An Biosphere Reserve, Vietnam; Tun Mustapha Marine Park, Malaysia; Taytay Bay, part of Palawan UNESCO UNESCO Man and Biosphere (MAB)Reserve, the Philippines; and Taka Bonerate Kepulauan Selayar (TBKS) UNESCO MAB Reserve, Indonesia.

For each case study, we identified the activities that interact with marine habitats, using local expert knowledge. We used a common typology of 11 pressures that can be introduced by those activities and can interact with five broad benthic and pelagic habitat types. Local expert teams, using their expert judgement, supported by literature evidence where available, systematically identified links between activities and pressures, then between activity-pressure combinations and their potential to overlap with each habitat in the case study sites. Expert elicitation was used to come to an agreement within the case study team and then across case studies as a group. An indication of confidence was given for each link. The confidence assessment had two tiers, one based on whether literature or other documented evidence was used in identifying links, and one based on expert judgement only. This process created the basic linkage framework, and one such matrix is provided for each case study site in this dataset.  

Each impact chain in the linkage framework was then weighted according to five criteria that capture either the exposure of a habitat to an impact risk or sensitivity of a habitat to an impact risk. Exposure criteria were the activity-pressure extent, frequency and persistence. Sensitivity criteria were the habitat resistance and resilience to an activity-pressure, capturing the likely severity of habitat damage, including taking into account the intensity or magnitude of the activity-pressure, and potential recovery. The same local expert teams weighted the extent and frequency criteria, which are specific to the case study sites. The identified impact chains were each considered in turn, available evidence was discussed, and expert elicitation was used to come to an agreement amongst the group. The other criteria, persistence, resistance and resilience, were weighted during a series of workshops with a research team with expertise on ecology of the habitats and on activity-pressure interactions with habitats. These criteria were considered specific to the activity-pressure interaction with the habitat rather than the specific location, and weightings were applied to generic impact chains rather than location specific chains. The intensity of the specific activity-pressure-habitat combination was taken into account where, for example, organic enrichment from shrimp farming overlapping with sediment habitats would result in lower resistance and resilience scores than from informal human settlements introducing the same pressure and overlapping with the same habitat. The evidence for the weighting of each criterion for each impact chain was discussed in turn and expert elicitation used to reach a consensus on categorisation. The generic weightings were then applied to the case study specific matrices and a further review was carried out by local expert teams in case of any exceptions to the generic weightings, for example if an activity-pressure combination had a greater magnitude of intensity in one location and/or habitat, making the consequence more severe, the score would be adjusted to account for this. As before, an indication of confidence was given for each weighting. One weighted linkage matrix is provided for each case study in this dataset.