Harvesting Effects on Species Composition and Distribution of Cover Attributes in Mixed Native Warm-Season Grass Stands

Vitalis Temu,Samuel Riffell,Brian Baldwin,K Reddy

doi:10.3390/environments2020167

Vitalis Temu, Samuel Riffell + Show 2 more

Open Access

https://doi.org/10.3390/environments2020167

Copy DOI

Abstract

Managing grasslands for forage and ground-nesting bird habitat requires appropriate defoliation strategies. Subsequent early-summer species composition in mixed stands of native warm-season grasses (Indiangrass (IG, Sorghastrum nutans), big bluestem (BB, Andropogon gerardii) and little bluestem (LB, Schizachyrium scoparium)) responding to harvest intervals (treatments, 30, 40, 60, 90 or 120 d) and durations (years in production) was assessed. Over three years, phased May harvestings were initiated on sets of randomized plots, ≥90 cm apart, in five replications (blocks) to produce one-, two- and three-year-old stands. Two weeks after harvest, the frequencies of occurrence of plant species, litter and bare ground, diagonally across each plot (line intercept), were compared. Harvest intervals did not influence proportions of dominant plant species, occurrence of major plant types or litter, but increased that of bare ground patches. Harvest duration increased the occurrence of herbaceous forbs and bare ground patches, decreased that of tall-growing forbs and litter, but without affecting that of perennial grasses, following a year with more September rainfall. Data suggest that one- or two-year full-season forage harvesting may not compromise subsequent breeding habitat for bobwhites and other ground-nesting birds in similar stands. It may take longer than a year’s rest for similar stands to recover from such changes in species composition.

Highlights

Tall-grass prairies once covered most of central North America and parts of the southeast [1,2]extending as far north as Canada and east into Mississippi and Alabama [3]
In the southeastern U.S, these tall-grass prairies were formed by native warm-season grasses (NWSG) dominated by perennials, such as big bluestem (BB, Andropogon gerardii Vitman), switchgrass (SG, Panicum virgatum L.), little bluestem, (LB, Schizachyrium scoparium (Michx) Nash), eastern gamagrass (EG, Tripsacum dactyloides (L.) L.) and Indiangrass (IG, Sorghastrum nutans (L.) Nash) interspersed with forbs and shrubs [1,3]
There were no treatments or year effects reflected in the frequencies of occurrence of forbs, which averaged about 15% and ≤14% for the short and tall ones, respectively (Table 4). These results suggest that forage harvesting alone may not compromise subsequent early-season wildlife habitat quality attributes associated with the spatial distribution of forbs in the stands

Summary

Introduction

Tall-grass prairies once covered most of central North America and parts of the southeast [1,2]extending as far north as Canada and east into Mississippi and Alabama [3]. There were sideoats grama (Bouteloua curtipendula (Michx) Torr.), Florida paspalum (Paspalum floridanum Michx), panicgrasses (Dichanthelium sp.), rivercane (Arundinaria gigantea (Walter) Muhl.) and purpletop (Tridens flavus (L.) Hitchc) [1]. These tall-grass prairies provided food and cover to grassland birds (northern bobwhite (Colinus virginianus), hereafter “bobwhite”, dickcissel (Spiza americana) and eastern meadowlark (Sturnella magna)) [4,5]. These structurally diverse plant communities had voids close to the ground for easy movements of young birds and provided good nest-building materials [1,6,7]. Some workers on NWSGs have reported 6%–12% crude protein and ≥70% dry matter digestibility [10,11]

Objectives

Results

Conclusion