Effects of short-duration kraaling depend on initial conditions in a mesic grassland

Abstract

Short-duration overnight kraaling has been suggested as a tool for restoring degraded rangelands. However, the response of different plant functional types and communities to such intense livestock impact may vary depending on local context. We thus examined the effects of short-duration overnight kraaling on soil and vegetation characteristics in a mesic montane grassland in South Africa using paired kraal and control sites, as part of a low intensity grazing approach. Kraaling increased soil P and S, as well as soil organic matter (except when initial values were over 12%). The effect of kraaling on vegetation was strongly dependent on initial condition. Basal cover of grasses and forbs increased by approximately 50 and 15%, respectively, if sites had very low initial basal cover, but decreased by up to 15% if initial values were over 50% and 10%, respectively. Kraaling always decreased herbaceous biomass, but especially when initial values were over 2 000 kg ha⁻¹. In mesic grasslands, short-duration overnight kraaling is promising as a tool for rehabilitating degraded sites or fertilizing abandoned cropland, but should be avoided where the grass sward is intact. We recommend that the suitability of kraaling be evaluated per vegetation type and local context.

Keywords:

• basal cover
• evolution
• invasive wattle
• soil organic matter
• phosphorus