Book Reviews

Book Review 1Book Title: Megaherbivores: the influence of very large body size on ecologyBook Author: R.N. Owen-SmithCambridge University Press, Cambridge, 1988. 369 pages.Book Review 2Book Title: Comparative Physiology of the Vertebrate KidneyBook Author: W.H. Dantzler Springer-Verlag 1989.198 pp. (Hardcover).Book Review 3Book Title: Atlas on the Biology of Soil ArthropodsBook Authors: G. Esenbeis & W. Wichard Springer-Verlag, Berlin 1987. 437 pp.Book Review 4Book Title: Primate Vocal CommunicationBook Authors: Edited by D. Todt, P. Goedeking & D. SymmesSpringer Verlag, Berlin (1988)Book Review 5Book Title: The Honey BeeBook Authors: J.L. Gould & C. G. GouldScientific American Ubrary, W.H.Freeman, New York. 239 pp.Book Review 6Book Title: Insect Development Photoperiodic and Temperature ControlBook Author: Victor A. ZaslavskiSpringer-Verlag, Berlin. 187 pp.Book Review 7Book Title: OrganellesBook Author: Mark CarrollMacmillan 1989. 202 pp.Book Review 8Book Title: Comparative Protozoology Ecology, Physiology, Life HistoryBook Author: O. Roger AndersonSpringer-Verlag, Berlin, 1988. 482pp.Book Review 9Book Title: Ecotoxicology: Problems and ApproachesBook Authors: Edited by S.A. Levin, M.A. Harwell, J.R. Kelly & K.D. KimballSpringer Verlag, New York. 547 pp

Mashing with unmalted sorghum using a novel low temperature enzyme system: impacts of sorghum grain composition and microstructure

Brewing lager beers from unmalted sorghum traditionally requires the use of high temperature mashing and exogenous enzymes to ensure adequate starch conversion. Here, a novel low-temperature mashing system is compared to a more traditional mash in terms of the wort quality produced (laboratory scale) from five unmalted sorghums (2 brewing and 3 non-brewing varieties). The low temperature mash generated worts of comparable quality to those resulting from a traditional energy intensive mash protocol. Furthermore, its performance was less dependent on sorghum raw material quality, such that it may facilitate the use of what were previously considered non-brewing varieties. Whilst brewing sorghums were of lower protein content, protein per se did not correlate with mashing performance. Rather, it was the way in which protein was structured (particularly the strength of protein starch interactions) which most influenced brewing performance. RVA profile was the easiest way of identifying this characteristic as potentially problematic

The mammals of Angola

Scientific investigations on the mammals of Angola started over 150 years ago, but information remains scarce and scattered, with only one recent published account. Here we provide a synthesis of the mammals of Angola based on a thorough survey of primary and grey literature, as well as recent unpublished records. We present a short history of mammal research, and provide brief information on each species known to occur in the country. Particular attention is given to endemic and near endemic species. We also provide a zoogeographic outline and information on the conservation of Angolan mammals. We found confirmed records for 291 native species, most of which from the orders Rodentia (85), Chiroptera (73), Carnivora (39), and Cetartiodactyla (33). There is a large number of endemic and near endemic species, most of which are rodents or bats. The large diversity of species is favoured by the wide range of habitats with contrasting environmental conditions, while endemism tends to be associated with unique physiographic settings such as the Angolan Escarpment. The mammal fauna of Angola includes 2 Critically Endangered, 2 Endangered, 11 Vulnerable, and 14 Near-Threatened species at the global scale. There are also 12 data deficient species, most of which are endemics or near endemics to the countryinfo:eu-repo/semantics/publishedVersio

Tree size as a factor influencing leaf emergence and leaf fall in <i>Acacia nigrescens</i> and <i>Combretum apiculatum </i>in the Kruger National Park

In Acacia nigrescens and Combretum apiculatum saplings tended to retain leaves over the dry season, whereas the mature trees generally lost most of their leaves. In Acacia nigrescens the production of new leaves over the dry season was more commonly observed in saplings than in mature trees

Habitat use by indigenous grazing ungulates in relation to sward structure and veld condition.

The objective of this study was to examine the relationships between the habitat requirements of different wild ungulate species, sward structure and veld condition. Veld condition score was correlated with sward height: habitats with high condition scores were dominated by tall grass species, whereas habitats with low scores were dominated by short grasses. Illustrates with tables; The objective of the study was to examine the relationships between the habitat requirements of different wild ungulate species, sward structure and veld condition. Veld condition score was correlated with sward height: habitats with high condition scores were dominated by tall grass species, whereas habitats with low scores were dominated by short grasses. This was because grass species that decrease as a result of heavy grazing ('decreaser' species) are typically tall, whereas those that are promoted by grazing ('increaser' species) are typically short. Grazers that require tall grasses (mountain zebra and red hartebeest) favoured habitat with high condition scores, whereas short grass grazers (black wildebeest) favoured range with low condition scores. The patch-selective grazing habits of the short grass grazers tended to create short grass lawns dominated by increaser grasses. The relevance of veld condition assessment for areas managed to support wild grazing ungulates is discussed.Language: EnglishKeywords: Grass; Niche separation; Specific habitat patches; Underlying hypothesis; Veld management; conservation; grazing; habitat; sward height; ungulates; veld condition assessment; veld condition score; sward structure; grazers; habitat requirements; habitats; grasses; mountain zebra; red hartebeest; black wildebeest; mountain zebra national park; eastern cape; south afric

Interrelationships Between Fire, Grazing and Grass Cover at the Bontebok National Park

Point surveys of permanently marked plots were conducted with the aim of (i) determining the change in grass height, cover and degree of defoliation with increasing time after veld burning and (ii) determining which plant species are most intensively defoliated by herbivores (mainly bontebok and grey rhebok). Grass was the most heavily defoliated component of the vegetation, whereas Restionaceae and Cyperaceae were generally avoided. No grass species was consistently avoided by herbivores, and no species was consistently favoured. Instead selection among species varied with growth stage. The tall, coarse species were favoured on new burns when the vegetation was still short. The short species came into favour once the sward had grown taller. Defoliation was heaviest within the first year after burning and thereafter decreased substantially. The introduction of coarse grass grazers such as mountain zebra to the park might lead to greater use of the mature veld. Those grass species that underwent the heaviest defoliation on new burns (over 50 of leaves severed) showed three- to seven-fold increases in canopy spread cover over subsequent years. Thus heavy use of recently burnt veld is not necessarily deleterious

A simple index of habitat suitability for Cape mountain zebras

An index of habitat suitability for Cape mountain zebras was calculated using two parameters: acceptability indices for different grass species, and the aerial cover of the grass species in the habitat. The index was tested by calculating its value for a range of different habitat patches and comparing this with the frequency of use of the patches by zebras. The close relationship between the index and the observed frequency of use verified that the index could be used as a guide to habitat suitability. Two methods were used to determine the frequency of use of the patches: counts of faecal pellet groups and frequency of sightings. Both methods yielded similar results but the pellet group counts were less time- consuming and expensive. It is recommended that the index of habitat suitability be used (i) as a parameter for monitoring of long-term changes in habitat suitability in the Mountain Zebra National Park and (ii) as a guide for selecting appropriate areas to re- introduce mountain zebras

The problem of maintaining large herbivores in small conservation areas: deterioration of the grassveld in the Addo Elephant National Park

Changes in vegetation cover and species composition in a grassland community during a six year period are reported. The grass Themeda triandra and the dwarf shrub Helichrysum rosum decreased in abundance, whereas the grass Eragrostis obtusa increased. Comparison of grazed plots with fenced plots revealed large herbivores were responsible for the increase in abundance ofE. obtusa. The abundance of T. triandra was influenced by large herbivores, but rainfall fluctuations apparently also played a role. The decline in relative abundance of/7. rosum was evidently not caused by large herbivores. Grass cover was closely determined by rainfall. A drought-induced decline in forage abundance evidently caused the buffalo population to crash

Resilience in agro-ecological landscapes: process principles and outcome indicators

This paper explores outcome indicators and process principles to evaluate landscape resilience in agro-ecosystems, drawing on outcome indicator case studies of the CGIAR Research Program on Water, Land and Ecosystems (WLE). Four questions are addressed: (1) which outcome indicators and process principles feature most prominently in the seminal literature on resilient agro-ecological landscapes? (2) to what extent are these principles represented in CGIAR Outcome Impact Case Reports (OICRs) and selected peer-reviewed studies? (3) how does the use of process principles in the case studies compare to their occurrence in the theoretical literature? and (4) which process principles co-occur with related outcome indicators in the OICRs? The findings enable researchers and practitioners to be more specific about the outcomes and processes that drive resilience in agro-ecosystems, thereby informing adaptive program management. Seven novel research themes are proposed