Using priority effects to manipulate competitive relationships in restoration

Abstract

Restoration success is often hampered by the failure of less dominant competitors to establish. An emerging literature on priority effects suggests the manipulation of community assembly as a useful technique to help overcome these difficulties by altering competitive relationships. We present data from a set of four priority experiments, carried out at each of three sites in restoration settings in California grasslands. These data, combined with patterns summarized from the literature, indicate that both short‐term priority (1–3 weeks) and long‐term priority (1 year) can profoundly shift interspecific relationships and benefit otherwise subordinate plant species, but that these effects are sometimes transitory, asymmetric, and contingent on environmental conditions and species composition. Restoration interventions that can produce priority effects include staggered planting times, weed control, seed pre‐germination, plug planting, and spatial aggregation. Such interventions are likely to be at least initially effective, but their strength and persistence can differ considerably across systems in space and time. Further research may help identify the conditions that maximize the strength and persistence of priority effects in restoration settings.

Outside the envelope: rare events disrupt the relationshipbetween climate factors and species interactions

“…), providing evidence that the impacts we see in this study will likely have persistent impacts on the plant community. Of course, our observation of the shifting strength of priority is most relevant in a restoration context in which suites of species are introduced in several stages, or non‐desired species are suppressed while desired species are establishing (Young et al., in press ). Community dynamics become more complicated when considering natural community assembly.…”

“…). However, the importance of priority effects in shaping communities varies across studies (Young et al., in press ). These effects are often contingent on environmental conditions during community assembly (Kardol et al.…”

“…, Tucker and Fukami ); in particular, site and year effects (Vaughn and Young ). Despite their apparent importance in driving community structure, such contingencies in community assembly processes are rarely explored outside of highly controlled laboratory or greenhouse conditions (Young et al., in press ).…”

Every restoration is unique: testing year effects and site effects as drivers of initial restoration trajectories

“…; Ejrnaes, Bruun & Graae ; Vaughn & Young ), and can be used to manipulate community trajectories to achieve the goals of ecological restoration (Young, Petersen & Clary ; Young et al . ). Environmental conditions during community establishment can be another important, yet experimentally underexplored, determinant of community composition (Berlow ; Belyea & Lancaster ; Chase ).…”

Recovery of nitrogen cycling in riparian zones after stream restoration using δ 15N along a 25-year chronosequence in northern Sweden

“…There was no seeding or planting of riparian plant species at our restoration sites and it could be that seeding or planting (planting preferred, see Dietrich et al 2015) could accelerate both the recovery of riparian species composition and N-processing. However, given that the arrival order of plants plays an important role for which type of vegetation will develop at restored sites (Sarneel et al 2016;Young et al 2016), the selection of species to be introduced has to be done with care.…”