An objective-based prioritization approach to improve trophic complexity through ecological restoration

Abstract

Reassembling ecological communities and rebuilding habitats through active restoration treatments requires curating the selection of plant species to use in seeding and planting mixes. Ideally, these mixes should be assembled based on attributes that support ecosystem function and services, promote plant and animal species interactions and ecological networks in restoration while balancing project constraints. Despite these critical considerations, it is common for species mixes to be selected opportunistically. Reframing the selection of seed mixes for restoration around ecological objectives is essential for success but accessible methods and tools are needed to support this effort. We developed a framework to optimize species seed mixes based on prioritizing plant species attributes to best support different objectives for ecosystem functions, services, and trophic relationships such as pollination, seed dispersal, and herbivory. We compared results to approaches where plant species are selected to represent plant taxonomic richness, dominant species, and at random. We tested our framework for 176 plant species found in European alpine grasslands and identified 163 associated attributes affiliated to trophic relationships, ecosystem functions, and services. In all cases, trophic relationships, ecosystem functions, and services can be captured more efficiently through objective based prioritization using the functional identity of plant species. Solutions (plant species lists) can be compared quantitatively, in terms of costs, species, or objectives. We confirm that a random draw of plant species from the regional plant species pool cannot be assumed to support other trophic groups and ecosystem functions and services. Synthesis and Applications. Our framework is presented as a proof of concept to help restoration practitioners better apply quantitative decision support to plant species selection in order to meet ecological restoration outcomes. Our approach may be tailored to any restoration initiative and habitat where seeding or planting mixes will be applied in active treatments. As global priority and resources are increasingly placed into restoration, this approach could be advanced to help make efficient decisions for many stages of the restoration process.

The function‐dominance correlation drives the direction and strength of biodiversity–ecosystem functioning relationships

“…Function–dominance correlations may be an effective ecosystem assessment tool that could be adopted by applied ecologists interested in maintaining or restoring ecosystem health. Assessing function–dominance relationships with respect to species losses and gains may allow better prioritisation of management actions for conservation and more function‐driven restoration (Ladouceur et al, 2021). Species loss and gain is commonly observed in many conservation areas, particularly those that lie within successional habitats such as old fields (Bourgeois et al, 2016; Walker et al, 2007).…”

The function-dominance correlation drives the direction and strength of biodiversity- ecosystem functioning relationships

“…Function-dominance correlations may be an effective ecosystem assessment tool that could be adopted by applied ecologists interested in maintaining or restoring ecosystem health. Assessing function-dominance relationships with respect to species losses and gains may allow better prioritisation of management actions for conservation and more function-driven restoration (Ladouceur et al, 2021). Species loss and gain is commonly observed in many conservation areas, particularly those that lie within successional habitats such as old fields (Bourgeois et al, 2016;Walker et al, 2007).…”

Translating the 10 golden rules of reforestation for coral reef restoration

“…For example, 20–30 pioneer and climax species of trees are recommended that typically have high survival, can grow and reproduce rapidly, and attract seed‐dispersing wildlife or that can “recapture” the site after disturbance (DiSacco et al., 2021). An “objective‐based prioritization” (Ladouceur et al., 2021) or “goal‐based” approach (Shaver et al., 2020), in which the outcome of an intended restoration activity is used as a guideline for action, has been developed for tree seed mixes, methods that logically carry over to coral restoration prioritization. For example, defining objectives for different restoration goals informs selection; a trait‐based approach helps define what species should be chosen given specific coral traits (Madin et al., 2021).…”

“…Considerations of phenotypic diversity are essential, and include choosing species from a range of functional groups and growth forms to maximize structural complexity and habitats for diversity and refugia. Although coral species boundaries are complex (e.g., Cowman et al., 2020), maintaining high biodiversity can be paired with maintaining functional or phenotypic diversity, resulting in greater protection of important ecosystem attributes (Ladouceur et al., 2021) (rule 6). Maintaining high genetic diversity is critical to sustain processes of sexual reproduction and natural cycles of coral recruitment, maximize the chances of building resistance, and prevent extinctions (e.g., Baums et al., 2019).…”