Establishment and Management of Native Functional Groups in Restoration

Abstract

The limiting similarity hypothesis predicts that communities should be more resistant to invasion by non-natives when they include natives with a diversity of traits from more than one functional group. In restoration, planting natives with a diversity of traits may result in competition between natives of different functional groups and may influence the efficacy of different seeding and maintenance methods, potentially impacting native establishment. We compare initial establishment and first-year performance of natives and the effectiveness of maintenance techniques in uniform versus mixed functional group plantings. We seeded ruderal herbaceous natives, longer-lived shrubby natives, or a mixture of the two functional groups using drill-and hand-seeding methods. Non-natives were left undisturbed, removed by hand-weeding and mowing, or treated with herbicide to test maintenance methods in a factorial design. Native functional groups had highest establishment, growth, and reproduction when planted alone, and hand-seeding resulted in more natives as well as more of the most common invasive, Brassica nigra. Wick herbicide removed more non-natives and resulted in greater reproduction of natives, while hand-weeding and mowing increased native density. Our results point to the importance of considering competition among native functional groups as well as between natives and invasives in restoration. Interactions among functional groups, seeding methods, and maintenance techniques indicate restoration will be easier to implement when natives with different traits are planted separately.

Revisiting the Holy Grail: using plant functional traits to understand ecological processes

“…Funk et al, 2008;Laughlin, 2014a). For example, traits have been used to identify native species from regional species pools that can tolerate certain abiotic conditions or compete with invasive species (Funk & McDaniel, 2010;Kimball et al, 2014), and re-establish critical ecosystem services (e.g. pollination services: Lavorel et al, 2011).…”

Aggregating Species at Seeding May Increase Initial Diversity during Grassland Reconstruction

“…While it is not realistic to expect that practitioners characterize all of the potential interactions among their desired species in order to proceed with reconstruction efforts, researchers and practitioners do need to determine whether initial species interactions can be manipulated to improve upon desired reconstruction outcomes (described in Porensky et al 2012, Houseman 2014, Kimball et al 2014). Increasing conspecific aggregation at seeding may prevent initial species losses during grassland establishment and it appears that intermixing species at seeding, which may not reflect typical grassland seed deposition patterns (Nathan and Muller-Landau 2000), may not be the most effective grassland seeding strategy.…”

“…Incorporating species-specific patterns into grassland seeding efforts may give individuals a necessary local advantage to increase species establishment from planned seed mixes (Grygiel et al 2009;Kimball et al 2014). To test whether or not species pattern at seeding can be manipulated to increase coarser-scale grassland diversity in the presence of an invader, we manipulated the number of conspecific individuals within the local neighborhood (aggregation) in a greenhouse experiment while maintaining pot-scale composition.…”

Seeding tallgrass prairie in monospecific patches promotes native species establishment and cover

“…This outcome is potentially attributable to the late season seeding, insufficient scarification, or simply poor seed batches (Greene & Curtis ; Wilson ). While undesirable, this outcome is common in the reconstruction process, especially for naturally infrequent forbs (Rowe ; Kimball et al ). Other species ( Andropogon gerardii , Panicum virgatum , Oligoneuron rigidum , and Bouteloua curtipendula ), performed well in monoculture (25–55% persistence), but did not persist consistently across the study treatments.…”