DOI: 10.5061/dryad.rjdfn2zbj
title: An objective-based prioritization approach to support trophic complexity through ecological restoration

description: 1. 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. 2. 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 in European alpine
 grasslands by identifying 176 plant species characteristic of the species
 pool, and identified 163 associated attributes affiliated to trophic
 relationships, ecosystem functions, and services. 3. 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. 4. 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.
description: We used species-rich European subalpine and alpine calcareous
 grasslands as a case study. These habitats are sensitive to disturbance,
 and impacted by ski resorts and other tourism activities, making them a
 target system for ecological restoration across European Natura 2000 sites
 (Garcia-Gonzalez, 2008, p.). We identified 176 plant species that
 frequently occur in the target ecosystem on a biogeographical scale as the
 potential regional and restoration species pool of interest (Ladouceur et
 al., 2018; Zobel et al., 1998). We used trait databases and literature to
 compile traits related to regeneration and relationships between the 176
 plant species in our species pool and the insects, birds and mammals that
 are typical of these habitats and depend on particular plant species for
 various life stages. Hereafter, we refer to the traits and aspects of
 plant species that represent these relationships and characteristics of
 interest, as plant attributes. We compiled a list of
 the most frequent native species occurring in alpine calcareous grassland
 habitat types on a continental scale, using a synthesis of  &gt;1
 million field surveys (Schaminée et al., 2016), reporting species
 frequencies in the habitat types of the European habitat classification
 system (EUNIS,
 www.eunis.org),
 directly assigned to habitat types of conservation concern (see Table S1).
 We identified native plant species that occur above a particular frequency
 (&gt;5% of total occurrences) in calcareous alpine grassland habitat
 types on a European-wide scale. Expert opinion suggests that species below
 this frequency were found to be more typical of other habitat types. This
 resulted in a list of 176 native plant species that occur frequently in
 the calcareous alpine grasslands of continental Europe. We considered this
 to be the species pool of this habitat and we assumed all species can
 co-occur or can co-exist. Further, we consider all plant species in the
 pool as equal candidates for inclusion in seed mixes to meet
 prioritization objective targets. For the 176 plant
 species that were of interest for our goals, we collated traits related to
 dispersal, phenology, and nitrogen fixation available from the TRY plant
 trait database (Kattge et al., 2011), as well as associations with
 mammals, birds, and herbivorous and pollinating insects from additional
 sources (see Table 1). The list of associated faunal species was refined
 to keep only species that occur in this habitat. Plant species frequency
 of occurrence values were used to rank plant species’ relative abundance
 within the habitat type on a biogeographic scale, which we used to
 classify plant species dominance for a fixed species list for comparison
 with prioritized objectives (Table 1, see Table S1). We
 then grouped the 163 plant attributes into nine broad categories based on
 the ability to support specific ecosystem functions or services (Table 1):
 bird trophic diet, bird herbivory, bird shelter, seed dispersal syndrome,
 Lepidoptera relationships (species specific- pollination, herbivory),
 pollination syndrome, mammal herbivory, nitrogen fixation, and flowering
 month. For references listed here please see associated
 publication.