Morphoecological characteristics of grasses used to restore degraded semi-arid African rangelands
Data files
Nov 10, 2020 version files 17.20 KB
Abstract
Progressive loss of productivity and plant diversity has been a major concern for land managers of global arid and semi-arid rangelands. This is often attributed to heavy grazing by large livestock herds and wildlife leading to land degradation threatening millions of livelihoods that rely on rangeland resources. Consequently, combating land degradation has increasingly become important global agenda. Active restoration technologies such as indigenous grass reseeding has been identified as a viable ecological solution for restoring degraded rangeland landscapes and providing forage for sustainable livestock production. Grass species indigenous to African rangelands Cenchrus ciliaris L. (African foxtail grass), Eragrostis superba Peyr. (Maasai love grass), Enteropogon macrostachyus (Hochst. Ex A. Rich.) Monro ex Benth. (Bush rye grass), Chloris roxburghiana Schult. (Horsetail grass) and Chloris gayana Kunth. cv Boma (Rhodes grass) were established in an African semi-arid rangeland landscape under natural conditions to compare their morphoecological characteristics and suitability for ecological restoration. Seed viability, seedling emergence, biomass dry matter yields, plant densities, basal cover, seed production, tiller densities and plant height were determined. Chloris gayana cv Boma and E. superba produced significantly higher dry matter biomass yields and seed production. High biomass and seed production demonstrate their suitability to support livestock production and replenish depleted soil seed banks, respectively. Enteropogon macrostachyus and C. ciliaris displayed significantly higher values for plant densities, tiller densities and basal cover, also used to measure establishment and ecological restoration success. Chloris roxburghiana ranked lowest in all the measured morphoecological characteristics. This could be a strong indicator of ecological site-specific characteristic of C. roxburghiana. Active restoration of degraded African semi-arid rangelands and forage provision for herbivores using indigenous grass reseeding can best be achieved through careful selection of grass species to take advantage on their specific multiple morphoecological characteristics. Furthermore, selection of the grass species to use should primarily be informed by the intended use of the rangeland.
Methods
Plant densities (plants m-2) and average tiller densities per plant species were estimated in three 0.25 m2 quadrats within each plot (Cox, 1990). Seed production was estimated from the biomass harvested and was separated from the stem and leaf biomass by hand stripping and weighed separately. Plant height (the tip of the top leaf) was determined using a 2 m ruler to the nearest centimetre. Percentage basal cover was estimated using the step-point method (Evans and Love, 1957).