Seeding is not always necessary to restore native early successional plant communities

Abstract

Restoration of native early successional plant communities in the eastern United States is a conservation priority because of declining populations of associated plants and wildlife. Restoration typically involves seeding native species and is often fraught with problems including weedy competition, expensive seed, and slow establishment. Pairing seed bank response with strategic herbicide applications may be an alternative approach for restoring these plant communities. We compared early successional plant communities established by seeding (SD) paired with selective herbicide use to natural revegetation (NR) from the seed bank paired with selective herbicide use at 18 locations that were previously row-crop or tall fescue (Schedonorus arundinaceus) fields in Tennessee, Alabama, and Kentucky, the United States. We did not detect differences in species diversity and richness, coverage of non-native grasses and forbs, or number and coverage of native flowering forbs by season between NR and SD treatments at tall fescue or fallow crop sites. Species evenness was greatest in NR and coverage of native-warm-season grasses in SD. Species richness and coverage of native forbs were least in untreated tall fescue units (CNTL). More flexibility to use herbicides with NR reduced coverage of sericea lespedeza (Lespedeza cuneata) in NR units compared to SD units at tall fescue sites. NR was 3.7 times cheaper than seeding. Land managers should consider using an NR approach to establish native early successional plant communities.

Plant Community Response and Implications for Wildlife Following Control of a Nonnative Perennial Grass

“…Managers using spot‐spraying apply less chemical than with broadcast applications. Spot‐spraying also has less negative effect on desirable species that might be susceptible to the herbicide used in a broadcast application, promoting increased colonization and spread of desirable species after undesirable species are controlled (GeFellers et al 2020).…”

“…Dominance of native grasses in Planted units led to reduced forb cover, which has been reported commonly (Weber 1999, Dickson and Busby 2009, Gruchy and Harper 2014), thus reducing nutritional carrying capacity for deer and necessitating a reduction in grass cover to improve forage availability (Brooke and Harper 2016). We underscore the importance of including variables important to white‐tailed deer and wild turkey in our evaluation because they are the primary species of interest to private landowners, and if restoration of nonnative grassland to native, early‐successional plant communities benefits these species, state and federal agencies likely can impact additional acres for species of conservation concern, including pollinators (GeFellers et al 2020).…”

“…Although we made fewer entries into Planted units than Seedbank units, more entries into Planted units would have allowed greater control of undesirable vegetation. However, conservation program policy stating that cover of undesirable vegetation should be ≥30% before herbicide applications are warranted reduced the average number of entries into Planted units (GeFellers et al 2020). Because our study sites were widely distributed geographically and occurred in areas with differing site histories and soil types, establishment costs from our study should be representative of the cost to restore native early successional communities in tall fescue fields previously used for haying and grazing throughout a large portion of the eastern U.S.…”

“…Tall fescue presents problems for various wildlife because of its growth habit and its association with an endophytic fungus ( Neotyphodium coenophialum ) that infects >90% of the grass (Bacon and Siegel 1988, Stuedemann and Hoveland 1988, Ball et al 2003). The dense structure of tall fescue at ground level suppresses the seedbank, lowering plant diversity (GeFellers et al 2020); restricts movement of small wildlife species, and lacks vertical structure important for bobwhite chicks, wild turkey ( Meleagris gallopavo ) poults, and numerous other ground‐feeding wildlife species (Barnes et al 1995, Washburn et al 2000, Harper et al 2007, Barnes et al 2013). The endophyte fungus compounds the problem by giving tall fescue a competitive advantage over native plant species (Clay 1990, Latch 1993, Hill et al 1996, Salminen et al 2005, Rudgers et al 2010), especially during drought conditions; this grass also releases toxic ergot alkaloids that have negative effects on wildlife (Betsill et al 1979, Madej and Clay 1991, Clay et al 1993, Coley et al 1995, Conover and Messmer 1996).…”

How much does is cost to restore a grassland?

“…Future studies could determine the distribution of grassland restoration projects across the active‐passive restoration spectrum and whether there are indeed fewer projects following more passive approaches or whether the costs of passive approaches are just less likely to be evaluated (Zahawi et al 2014). This is especially important to establish given more cost‐effective grassland restoration outcomes are reported with passive restoration techniques (Valkó et al 2017; GeFellers et al 2020).…”