NbS Triple Win Toolkit: Biodiversity Indicators in Context 37 diversity of projects increases – e.g. absolute changes in species diversity are not directly comparable between taxa or ecosystems.The SER restoration scale may provide a way to bridge the gap, because changes in project-level indicators could then be matched against this scale for higher level reporting. Species Tracking species responses is a clear and direct way of monitoring the impact of activities on biodiversity. However, it is difficult to aggregate species trends into a headline indicator, as species represented will necessarily differ depending on representative composition, difficulty in surveying, importance of species to the area and likely time lag between activities and impact on species – all of which will be site-dependent. An aggregated KPI has therefore not been recommended for the ICF portfolio of investments, however it could be consideredas a valuable addition to project- or programme-level indicators. Abundance of selected species At a project level trends in the abundance of selected species can be used to establish impacts of NbS on biodiversity. Project teams would need to select species that are expected to react to the NbS interventions within the project timescales and/or expected to be indicative of the state of biodiversity. Selection of species is challenging, as an “indicator” species may not be truly representative of wider biodiversity, while reporting trends in generalist species will not provide an accurate measure of biodiversity. Species selection may also depend on the ease of collecting abundance data. For considerations specific to marine species, see marine indicators in context. The project would need to justify the species selection, preferably with evidence or literature supporting the selection. The project teams would need to conduct a field survey to estimate selected species’ abundance before NbS interventions began as a baseline, and continue to conduct field surveys throughout the project, reporting change in species abundance at appropriate intervals. This would provide a direct measure of species abundance, but requires less resource than sampling all species at a location, and provides flexibility for projects to select appropriate species to measure.A particular challenge however is being confident to attribute changein abundance to the direct impacts of the programme activities. Species richness An increase in species richness is not necessarily a desirable outcome of interventions. Specifically, certain habitats are naturally less species diverse, and an increase in species richness would be as a result of colonisation by generalists and/or non-native species, potentially at the expense of habitat specialists. It has therefore not been recommended as a headline indicator. However, it is likely to be representative of achieving biodiversity benefits in project areas of degraded habitat that are not aiming to return to a near-natural state, including agroforestryor rotational agriculture projects. An increased species richness ina rotational agriculture area compared to intensive crop production would demonstrate the positive impact these interventions have despite continued anthropogenic land use. If this type of species richness is applicable to many NbS projects, for instance the ICF portfolio benefits a significant area of agricultural lands aiming to reduce negative impacts and improve local biodiversity, funders may consider developing a species richness headline indicator.