Researchers and practitioners have different views on seed transfer for ecological restoration

To bend the biodiversity loss curve, conservation alone is not sufficient, ecological restoration is also required. The ambitious goals of international initiatives, like the UN Decade on Ecosystem Restoration 2020-2030, or the post-2020 target of the Convention on Biological Diversity (CBD) is to achieve restorative management on 30 % of degraded land by 2030. It requires large areas to be returned to natural and semi-natural ecosystems globally, partly with the help of plant species translocations and introductions, mainly with seeding. However, seed provenancing is an actual scientific and practical challenge. We aimed to highlight the synergies and potential mismatches between practice and research in order to enhance future discussions and by that fine-tuning provenancing frameworks.

In this perspectives article, first we describe the debate on local versus broad provenancing and the benefits and challenges related to the different approaches. For this we provided an overview on the current state of the art discussing the pros and cons about local and broad scale provenancing. The traditional approach and the precautionary principle suggest prioritising local seed sources, if available. Local adaptation is the main rationale for preferring seeds from surrounding populations, assuming that local (regional) genotypes have the highest potential for survival at the restored site. However, low genetic variability and inbreeding depression, often typical of small local populations, might decrease the feasibility of this approach. Local provenancing can also be criticized for not taking climate change into consideration. There is a growing literature promoting the use of a broader genetic diversity to restore climate-resilient communities. But broad provenancing can result in maladaptation, a threat to the integrity of the natural genetic structure. Also, when using seeds from distant sources, phenological asynchrony (e.g. in flowering time) can reduce the viability of the established populations and at the same time endanger populations of pollinators. As a solution to these dilemmas, seed transfer zones as provenance ranges were developed as a surrogate measure when species-specific genetic information is missing. It should be noted that in many situations debate on local or broad provenance remains academic until seed sourcing is burdened by many practical problems, especially seed shortage.

In order to provide a deeper insight, we compiled a stakeholder survey involving restoration and conservation experts, and practitioners related to this issue. 75% of respondents already faced the problem of seed provenancing during their work. Altogether 40 participants took part in the survey. Among the workshop participants, 14, 11, and 15 identified themselves as restoration ecologist scientists, ecological restoration practitioners and other conservation experts, respectively. We asked the participants to anonymously write their opinions in free text using their own words about local vs. broad provenancing, and about the most important future directions on research and practice. Keywords were assigned to the responses and categorized along a local/broad provenancing and research/action scale. Results showed markedly different attitudes of researchers and practitioners. Researchers tended to stress the importance of applying ecological knowledge based on research, such as proper planning by defining aims and prioritization, using genetic knowledge, and species focus. However, they rarely considered practicalities and methodological constraints, like cost efficiency, feasibility, and broad provenance and considered rapid action less important. Practitioners facing difficulties on site rather mentioned keywords related to effective practical implementation, such as broad provenance, feasibility, landscape context, and rapid action.

We merged the knowledge gained from the literature with that of the stakeholder survey and proposed a simple decision support framework on provenancing in restoration. The framework considers the critical intersections of assessments and decisions, the importance of science and practice at different stages, and includes the role of stakeholders in the process. (Please find the three step decision support framework in the attached multimedia. For more information on restoration-related research, please visit the website of the Restoration Ecology Group  and the LENDÜLET Seed Ecology Research Group 

We suggest building on similar expert groups as surveyed in this study as a core stakeholder group to further involve decision makers, seed producers, conservation experts and relevant authorities in the discussion on how to improve policy and practice on seed sourcing for ecological restoration. What is needed is to dive into restoration implementation, jointly find bottlenecks, such as seed sourcing, and solve the problems by using the best available knowledge and necessary compromises.