Tradeoffs in Performance of Native Warm‐Season Grass Cultivars and Locally Harvested Seed Managed for Wildlife Habitat or Livestock Production

Abstract

or mechanical, including photocopying, recording, or any information storage and retrieval system, without permission in writing from the publisher. conservation practitioners and managers advocate the use of LHS (Jones, 2003;McKay et al., 2005), which theoretically is adapted to the local environmental conditions of a region (McMillan, 1969) and maintains the genetic integrity of local plant populations (Bischoff et al., 2010). However, LHS may not be suited for agronomic applications such as repeated defoliations under rotational grazing and as a result may not ABSTRACT Native warm-season grasses have potential to increase the ecosystem services associated with grazing lands and to provide a source of forage for livestock. In the upper Midwest, minimal region specifi c information is available to grass-based farmers on how to manage native pastures for long-term productivity and persistence. Wildlife biologists suggest delaying defoliations until mid-summer to preserve grassland bird habitat, yet production-based management recommendations warn against late season defoliations. Moreover, the source of seed to use for pasture establishment, cultivar or locally harvested seed (LHS), is unclear. We initiated an on-farm experiment to evaluate the eff ects of two rotational grazing schedules, June to July or July to September, for diff erences in vegetation cover, vigor, yield, and nutritive value of paddocks seeded with native warm-season grass cultivars or LHS. Aft er 2 yr, native grass cover was similar across all treatments. Vigor, as measured by spring etiolated growth, was sustained under grazing and across seed sources for the dominant native grasses big bluestem (Andropogon gerardii Vitman) and Indiangrass [Sorghastrum nutans (L.) Nash]. Total yield was greatest when grazing was deferred until July, but this resulted in decreased nutritive value for both seed sources. Th ese results indicate that native warm-season grasses have potential to persist under rotational grazing in upper Midwest pasture systems and that pasture performance is controlled by the timing of the fi rst grazing cycle. Th e lack of a consistent seed source eff ect suggests that the LHS and cultivars used in the study are suitable for pasture use in the region.

Converting exotic forages to native warm-season grass can increase avian productivity in beef production systems

“…Nevertheless, producers also would forego most economic opportunities with land-sparing. If NWSG pastures are managed with reduced stocking rates, deferment, or resting (Chamberlain et al, 2012;Harper et al, 2015;Mousel et al, 2003), our study indicates that employing such management in a land-sharing regime may increase availability of dickcissel nesting habitat relative to exotic grass pastures. An important caveat is that we did not consider other members of the avian grassland community such as grasshopper sparrows that may respond positively to pastures and fields with lower vegetation structure (Johnson and Sandercock, 2010;Hovick et al, 2012;McCoy et al, 1999).…”

“…Native warm-season grasses (NWSG) are increasingly promoted as a sustainable alternative to exotic forages because of their lower input requirements and drought tolerance (Harper et al, 2007), but NWSG also may create suitable nesting habitat for grassland birds (Giuliano and Daves, 2002;Harper et al, 2015;Hughes et al, 1999). In addition to the greater height and structural complexity of native bunchgrasses, these forages generally are not grazed as heavily as exotic grass pasture (Chamberlain et al, 2012;Harper et al, 2015;Mousel et al, 2003), and thus may retain structure for cover and nesting. Grazed NWSG therefore may be a land-sharing alternative to exotic forages and set aside programs, offering benefits for wildlife while also permitting beef production.…”

Testing the cultivar vigor hypothesis: comparisons of the competitive ability of wild and cultivated populations of Pascopyrum smithii along a restoration chronosequence

“…Rydgren et al () determined that three of five species seeded on spoil heaps persisted in large numbers 20–30 years postrestoration with little increase in cover, but authors did not differentiate seed sources. Chamberlain et al () examined persistence of cultivated and locally harvested sources of A. gerardii and S. nutans under rotational grazing and detected no differences in persistence over 2 years, but did not follow plantings any longer. Our study therefore represents one of the first to track the long‐term persistence of cultivars in ecological restoration.…”

Spread of exotic grass in grazed native grass pastures and responses of insect communities

“…In addition, less precipitation in 2012 during the early part of the growing season (April–June) could have subjected native forages to additional stress and further limited their ability to compete with bermudagrass when grazed. Reduced stocking rates, deferment, or rest from grazing may maintain productivity of NWSG (Mousel et al ; Chamberlain et al ; Harper et al ) and thereby their competitive advantage over shorter species such as bermudagrass.…”