The use of spatially patterned methods for vegetation restoration and management across systems

Abstract

Widespread degradation of natural lands has created an urgent need for restoration. However, the high cost of conventional techniques limits the extent and success of restoration efforts. As a result, practitioners have developed new cost‐effective techniques. Spatially patterned restoration methods, where established clusters of plant species serve as propagule sources across a broad target area, have been proposed as practical restoration techniques. The spatial patterning is expected to reduce initial costs and provide ecological benefits such as increasing habitat heterogeneity. Over the past three decades, multiple spatially patterned restoration methods have emerged around the globe; however, it is unclear whether applications and theoretical foundations have been connected across methods. We conducted a literature review and bibliometric network analyses to (1) examine patterns in focal study systems, cost‐effectiveness, and ecological outcomes for spatially patterned restoration methods and (2) analyze connectivity among the bodies of literature associated with common spatially patterned restoration methods to identify knowledge gaps and synergies. We found the three most commonly studied methods are applied nucleation, slot seeding, and strip seeding. Applied nucleation studies mainly occurred in tropical forests and emphasized plant diversity and seed‐dispersing animal visitation. Slot‐seeding and strip‐seeding studies both primarily occurred in temperate grasslands and emphasized plant establishment and production. Applied nucleation and slot‐seeding approaches had distinct theoretical bases, as evidenced by patterns in reference citation, while strip‐seeding approaches did not draw from a unified body of literature. We discuss the need for full economic analyses and theoretical links between the different methods.

Vegetative spread is key to applied nucleation success in non‐native‐dominated grasslands

“…This result is consistent with prior applied nucleation research in grasslands and forests (e.g. Corbin et al 2016;Holl et al 2017;Grygiel et al 2018), as well as studies on other spatially patterned planting designs (Gornish et al 2019;Shaw et al 2020), showing that some species spread outside the planted areas. Using spatially patterned plantings is ecologically beneficial since it creates a more heterogeneous plant distribution that mimics the small-scale heterogeneity characteristic of grassland ecosystems (Seabloom et al 2005;Gornish et al 2019).…”

Precision restoration: a necessary approach to foster forest recovery in the 21st century

“…Besides caring for the maintenance or recovery of the populations of the disperser, it is also necessary to have a minimum of scattered nuclei or individual trees in the landscape that act as seed sources. Therefore, another PFR approach could be to concentrate efforts in creating such nuclei or promoting those that remain in the landscape (Holl et al 2019; Shaw et al 2020), including fencing (protection against herbivores), pruning, fertilization, irrigation, elimination of weed competition, or any other action that can accelerate the growth of trees (Fig. 3B).…”

Can Nucleation Bridge to Desirable Alternative Stable States? Theory and Applications

“…Unlike many other restoration strategies, ecological nucleation recognizes that many vital ecological interactions occur at the local scale and that these local interactions can be leveraged to initiate desirable landscape‐scale changes in ecosystem structure and function. Past applications of ecological nucleation have used it as an analogy to describe the growth of recently established patches of the desired state, which can accelerate that state’s spread (Yarranton and Morrison 1974, Corbin and Holl 2012, Hulvey et al 2017, Shaw et al 2020). More recently, autocatalytic nucleation has been more strictly defined in ecology as the process by which a critical patch size of the desired state can lower resistance thresholds and catalyze rapid growth through local positive feedback dynamics (Michaels et al 2020).…”

“…Karen Holl discussed research on applied nucleation (i.e., planting patches or nuclei of trees) and other spatially patterned (Shaw et al 2020) planting methods (e.g., planting in strips) as more promising methods to accelerate forest succession and create more heterogeneous habitat than standard, plantation‐style tree planting approaches. She summarized key lessons learned from the long‐term, well‐replicated applied nucleation study that she, Dr. Rakan Zahawi, and many other collaborators have been conducting in southern Costa Rica.…”