Spatial and temporal effects of grazing management and rainfall on the vertebrate fauna of a tropical savanna

Grazing by domestic livestock is one of the most widespread uses of the rangelands of Australia. There is limited information on the effects of grazing by domestic livestock on the vertebrate fauna of Australia and the establishment of a long-term grazing experiment in north-eastern Queensland at Wambiana provided an opportunity to attempt an examination of the changes in vertebrate fauna as a consequence of the manipulation of stocking rates. The aim was to identify what the relative effects of vegetation type, stocking rate and other landscape-scale environmental factors were on the patterns recorded. Sixteen 1-ha sites were established within three replicated treatments (moderate, heavy and variable stocking rates). The sites were sampled in the wet and dry seasons in 1999-2000 (T-0) and again in 2003-04 (T-1). All paddocks of the treatments were burnt in 1999. Average annual rainfall declined markedly between the two sampling periods, which made interpretation of the data difficult. A total of 127 species of vertebrate fauna comprising five amphibian, 83 bird, 27 reptile and 12 mammal species were recorded. There was strong separation in faunal composition from T-0 to T-1 although changes in mean compositional dissimilarity between the grazing stocking rate treatments were less well defined. There was a relative change in abundance of 24 bird, four mammal and five reptile species from T-0 to T-1. The generalised linear modelling identified that, in the T-1 data, there was significant variation in the abundance of 16 species explained by the grazing and vegetation factors. This study demonstrated that vertebrate fauna assemblage did change and that these changes were attributable to the interplay between the stocking rates, the vegetation types on the sites surveyed, the burning of the experimental paddocks and the decrease in rainfall over the course of the two surveys. It is recommended that the experiment is sampled again but that the focus should be on a rapid survey of abundant taxa (i.e. birds and reptiles) to allow an increase in the frequency of sampling and replication of the data. This would help to articulate more clearly the trajectory of vertebrate change due to the relative effects of stocking rates compared with wider landscape environmental changes. Given the increasing focus on pastoral development in northern Australia, any opportunity to incorporate the collection of data on biodiversity into grazing manipulation experiments should be taken for the assessment of the effects of land management on faunal species

Degradation of communal rangelands in South Africa: towards an improved understanding to inform policy

In South Africa, the relative extent of range degradation under freehold compared to communal tenure has been strongly debated. We present a perspective on the processes that drive rangeland degradation on land under communal tenure. Our findings are based on literature as well as extensive field work on both old communal lands and ‘released’ areas, where freehold farms have been transferred to communal ownership. We discuss the patterns of degradation that have accompanied communal stewardship and make recommendations on the direction policy should follow to prevent further degradation and mediate rehabilitation of existing degraded land.Keywords: communal rangelands, land degradation, rehabilitation, social systemsAfrican Journal of Range & Forage Science 2013, 30(1&2): 57–6

Plant structure and the acceptability of different grasses to sheep

Plant structure should be an important determinant of species acceptability to grazing ungulates functioning under various time-energy constraints. The acceptability of 9 grasses to sheep grazing a secondary grassland community in spring, summer, and autumn in South Africa was related to the following species attributes: plant height, leaf table height, tussock diameter, stemminess, percent leaf, leaf density, percent dry matter (DM), leaf tensile strength, and leaf crude protein (CP). Species acceptability over the grazing season was positively related to tussock diameter (P less than or equal to 0.05) but negatively related (P less than or equal to 0.01) to leaf tensile strength and DM. Discriminant function analysis successfully discriminated between species in different acceptability classes in summer (P less than or equal to 0.05) and autumn (P less than or equal to 0.01) using a combination of plant structure and leaf quality attributes. Correspondence analysis indicated that preferred species were generally short and nonstemmy and had leaves of low DM, low tensile strength, and high crude protein content. Conversely, avoided species tended to be tall and stemmy with a high leaf table height, and had leaves of high DM and tensile strength but low CP levels. It is concluded that, for sheep, acceptability is determined by a combination of plant structure and leaf quality attributes.This material was digitized as part of a cooperative project between the Society for Range Management and the University of Arizona Libraries.The Journal of Range Management archives are made available by the Society for Range Management and the University of Arizona Libraries. Contact [email protected] for further information.Migrated from OJS platform August 202

Nutrition of sheep under rangeland conditions

The following chapter addresses specific problems associated with the nutrition of sheep on rangelands, including variable feed quality and water availability, as well as the use of supplementary feeding to correct nutrient deficiencies for sheep grazing in these environments. Variability in feed quality and intake are discussed in terms of spatial (plant, patch and landscape levels) and temporal (short- to medium-term, longer intra-annual, and interseasonal variability) variations in forage quality and supply. The chapter elaborates on sustainable resource management of rangeland systems and feed supplementation under rangeland conditions

Sequence of species selection by cattle and sheep on South African sourveld

The sequence of species selection over the grazing period directly determines the effectiveness of different grazing systems. Knowledge of this sequence is also important in understanding the plant-animal interface. The sequence of tiller defoliation by cattle and sheep was compared for 7 range grasses at 4 different sites in South African sourveld. Defoliation frequency and height was monitored daily over a 6-day grazing period at each site. The sequence of species selection was the same for cattle and sheep although the acceptability of some grasses varied between animal species. Preferred species were always grazed first along with some (<20%) utilization of species of intermediate acceptability. When about 60% of the tillers of the preferred species had been defoliated, regrazing of these tillers commenced and the rate of utilization of intermediate species increased. Only after 80 to 100% of the tillers of preferred and intermediate species had been defoliated were tillers of the least-preferred species grazed. Sheep were more selective and tended to graze the least-preferred species later in the grazing period than did cattle. There was no difference between cattle and sheep in the frequency of tiller defoliation over the grazing period but tillers were defoliat- ed to a lower height (P < 0.01) and more tissue removed (P<0.01) under sheep grazing. Cattle and sheep are therefore likely to differ in their potential impact upon rangeland.The Journal of Range Management archives are made available by the Society for Range Management and the University of Arizona Libraries. Contact [email protected] for further information.Migrated from OJS platform August 202

Watching the grasses grow: using UAVs and satellites to monitor rangeland species composition

Rangeland monitoring methods traditionally involve intensive and time consuming fieldwork. New sensing technologies (e.g. drones, satellite imagery) have the ability to rapidly collect large data sets at relatively low cost. These data are operationally used for greenness and cover analysis but due to the complexity of grass phenological response, the classification of individual species remains a challenge. This paper reports on new research using unmanned aerial vehicles (UAVs) with a multi-spectral camera to monitor the temporal reflectance changes of four grass species (Bothriochloa pertusa, Bothriochloa ewartiana, Heteropogon contortus and Aristida sp.) common in rangelands of north Queensland