Timothy M. Crowe

Waterbird assemblages and associated habitat characteristics of farm ponds in the Western Cape, South Africa

Natural freshwater wetlands are among the most threatened habitats on Earth. Effective wetland biodiversity conservation can not, however, be evaluated without fully understanding the roles of artificial waterbodies as refuges for water-dependent plants and animals. Waterbird assemblages were examined on 59 farm ponds in the Elgin and Caledon districts of the Western Cape, South Africa. This study examines the relationship between waterbird use and habitat characteristics of farm ponds. Patterns of temporal and spatial variation of waterbird species richness and abundance were quantified in relation to the habitat characteristics of each pond. Cluster analysis and multiple regression analyses identified surface area of the farm ponds as an important variable determining the presence and abundance of many waterbird species. Structural diversity in terms of vegetation in and around the ponds was especially important in determining their usage by waterbirds. These variables were evaluated in terms of creating a mosaic of habitat types (by varying vegetation structure and pond topography), which may be a useful way to enhance waterbird diversity at farm ponds. This study concludes that the high number of farm ponds in the transformed habitat matrix of the Western Cape plays an important role in conserving waterbirds.

SYSTEMATICS AND BIOGEOGRAPHY OF DOUBLE-COLLARED SUNBIRDS FROM THE EASTERN ARC MOUNTAINS, TANZANIA

Abstract The double-collared sunbirds of the Eastern Arc Mountains of Tanzania and southeastern Kenya are characterized by regional variation in morphology and plumage. That variation has resulted in considerable dispute over their taxonomic status and delineation of range boundaries. It has been suggested that Moreaus Sunbird (Nectarinia Moreaui) is an atypical phenotype that has arisen from a hybridization event between the more widely distributed Eastern Double-collared Sunbird (N. mediocris) and the narrowly distributed Loveridges Sunbird (N. loveridgei). A discriminant analysis of six standard morphological characters indicates that Moreaus Sunbird is intermediate in shape and size between the Eastern Double-collared and Loveridges sunbirds. There is greater overlap between female Moreaus and Eastern Double-collared sunbirds than between males; Loveridges Sunbird shows little overlap with the other taxa. Discrete plumage characters separate all three taxa. Molecular analyses of 728 base pairs of mitochondrial DNA (NADH3 and control region) suggest that Moreaus Sunbird is a valid taxon and the sister species to Loveridges Sunbird. Eastern Double-collared Sunbird haplotypes can be divided into three distinct clades, separated from each other by substantial genetic divergence (approximately 8–10% sequence divergence). We propose species status for each of those clades and suggest the following three taxa: N. mediocris Shelley 1855, N. usambarica Gröte 1922, and N. fuelleborni Reichenow 1899. Finally, we propose a biogeographical hypothesis of speciation events within the N. mediocris species complex.

Implications of grazing and burning of grasslands on the sustainable use of francolins (Francolinus spp.) and on overall bird conservation in the highlands of Mpumalanga province, South Africa

We investigated the densities of the Redwing Francolinus levaillantii and Greywing Francolins F. africanus and the diversity of grassland birds in general along a land-use gradient in the highlands of Mpumalanga province, South Africa. Redwing Francolins cannot tolerate intensive grazing and frequent burning and are confined largely to unburnt, ungrazed grasslands. Their density and the species richness of grassland birds in general are negatively correlated with grazing intensity. Redwing populations drop to densities that cannot be utilised by hunters on a sustainable basis in grasslands that are grazed at even moderate levels or burned annually. Nineteen bird species (including five threatened species) were confined to essentially pristine grassland and were never observed in grazed/annually burned grasslands. The Greywing Francolin is more evenly distributed (although always at sub-utilisation densities) along the grassland land-use gradient, and its density is positively correlated with grazing intensity. There are two assemblages of grassland bird species that appear to be indicative of the intensity of habitat utilisation. Populations of grassland birds in the study area are becoming increasingly dependent on isolated patches of pristine grassland and are threatened by management involving annual burning and high stocking rates on a landscape scale.

Patterns of distribution, diversity and endemism of larger African Mammals

Patterns of distribution and diversity (= species richness) of larger African mammals, and three subsets thereof (ungulates, carnivores and primates), are identified and analysed quantitatively. Distributional patterns generally correspond well with those of present-day vegetation types and of resident non-aquatic birds. However, the precise locations of zonal boundaries and the degree of zonation differ between groups, primarily reflecting their different ecological requirements. Large mammal diversity increases towards the equator, but diversity patterns differ substantially between the groups. Diversity is positively correlated with vegetation type diversity, and vegetation types analysed as separate units explain over 85% of the variance in the diversity of the mammal groups investigated. In addition, both distributional and diversity patterns appear to have been affected by past environmental factors.

Phylogenetic, taxonomic and biogeographical implications of genetic, morphological, and behavioral variation in Francolins (Phasianidae : Francolinus)

ASSTRACT.--We studied restriction-fragment length polymorphisms (RFLPs) in mitochondria! DNA for 13 species of African franco!ins (Francolinus pp.) and the Japanese Quail (Coturnix c. japonica). Phylogenetic analyses of RFLPs for these 14 species and of morphological and behavioral characters for the 41 francolin species and other perdicine taxa do not confirm the monophyly of Francolinus as currently recognized. Analyses of morpho-behaviora! characters suggest that Francolinus consists of at least four major assemblages: the five Asiatic species; two groups of African quail-like species; and the African partridge-like species. Within these assemblages, analyses of RFLPs and/or morpho-behaviora! characters upport the monophy!y of six of eight species groups attributed to Francolinus. Assuming the monophy!y of currently recognized supraspecific groups of ga!!iform birds, morphometric analyses of gal!iform skeletons correctly classified 90-99% of specimens to family, subfami!y and tribe, as well as 95% of the francolin specimens to genus. Genetic distances derived from RFLP data imply that African francolins diverged from their sister taxa at or before the mid-late Miocene, and that a!! species studied diverged from their sister-species during the Pliocene or early Pleistocene. Received 29 June 1990, accepted 13 July 1991.

Patterns of species richness and narrow endemism of terrestrial bird species in the Afrotropical Region

Geographical patterns and peaks of species richness and narrow endemism (defined by range-restrictedness and range-size rarity) are described for terrestrial Afrotropical birds and subsets thereof based on residency, endemism, and taxonomy. Species richness for residents and Afrotropical endemics (species globally restricted to sub-Saharan Africa) peaks along the mountains and adjacent lowlands of eastern and southern Africa. Isolated mountains in central and western Africa and the lowlands of the north-eastern Congo Basin (Ituri) are highlighted to a lesser degree. Peaks of narrow endemism occur in these areas as well as in the Ethiopian Highlands (particularly for non-passerines), Somalia (particularly for passerines), and the Angolan Escarpment. Within residents, patterns of species richness vary greatly between Afrotropical endemics (which concentrate in forests on mountains and adjacent lowlands, and the southern Brachystegia woodlands) and non-endemic residents (which concentrate in Sudanian woodlands and the Ethiopian Highlands). Patterns of species richness of residents (species that breed in the Afrotropics) and non-breeding migrants (non-breeding visitors to the Afrotropics) also show notable differences. The latter concentrate in areas close to the Palaearctic, which forms their distributional range centres. Patterns of species richness and narrow endemism for Afrotropical endemics show broad-scale coincidence within mountains or mountain–lowland complexes, particularly the Cameroon–Bamenda Highland system, East African rift system and Eastern Arc mountains. However, fine-scale coincidence of peaks of species richness and narrow endemism within these complexes is low. Narrow endemism peaks occur in areas of topographical complexity, which may have conferred localized climatic stability over short-, medium-, and long-term climatic cycles (sensu Fjeldsa, 1994; Fjeldsaet al., 1997), allowing these areas to act as ‘species pumps’. Species accumulate in areas of high productivity. Lack of fine-scale coincidence of narrow endemism and species richness peaks have implications for conservation prioritization exercises.

Phylogenetic relationships and rates of allozyme evolution within the Phasianidae

Abstract Phylogenetic relationships among 12 galliform species belonging to the superfamily Phasianoidea were studied with multilocus protein electrophoresis. Neis standard genetic distances ranged from D = 0.081 between Alectoris rufa and A. graeca , to D = 1.292 between Pavo cristatus and Lagopus mutus . Dendrograms were generated using distance matrix and discrete character states methods. The phylogenies obtained were generally congruent with previous estimates based on protein electrophoresis, DNA-DNA hybridization, nuclear DNA restriction maps and karyology, but they were not in accordance with phylogenies suggested by current classifications. In our study Numida and Pavo were distantly related to the other taxa studied and the Phasianidae, sensu Storer [Storer, R. W. (1971) Classification of Birds, in Avian Biology (Famer, D. S. and King, J. R., eds), Vol. 1, pp. 1–18. Academic Press, New York.], appears to be a genetically highly heterogeneous group. Taxonomically, the Phasianidae could be split into two lineages: the first one comprising Meleagris, Phasianus, Perdix and the grouse; the second one linking the partridges of the genus Alectoris with the Old World and the New World quails. The relative rate test suggested consistent homogeneity of the rate of protein evolution in all lineages obtained using analyses of distance data, except the one including Numida . The latter showed a slowdown, possibly due to underestimation of its genetic distances with the other taxa, or to erroneous classification of its fossil ancestor. A calibration of the molecular clock based on a study of nuclear DNA produced the relation 1D = 22.9 million years (Myr), which was used to estimate the divergence times between lineages. Divergence times were compared with the utilizable fossil record. These results suggest that multilocus protein electrophoresis is a reliable method of studying bird phylogenetic relationships spanning from the subspecific to the intraordinal level.

Population dynamics and the physical and financial impacts to cereal crops of the Egyptian Goose Alopochen aegyptiacus on the Agulhas Plain, Western Cape, South Africa

Cereal crop farmers in the Western Cape province of South Africa regard the Egyptian Goose as a serious pest. The Agulhas Plain, in particular, attracts thousands of geese annually primarily because of the abundance and availability of nutritious crops such as wheat Triticum spp. and barley Hordeum spp. for food and permanent water bodies for roosting, moulting and breeding. Therefore, this paper investigates the population dynamics and physical and financial impacts to cereal crops of the Egyptian Goose on the Agulhas Plain, Western Cape. Egyptian Geese inflict damage during three main periods, viz. soon after sowing (surface seeds); young, developing plants (growing plants); and cut plants stacked in windrows (long, linear piles) to dry. The largest numbers of geese were recorded during June and July when they foraged on growing plants less than 25 cm tall. Overall, the mean yield loss was 65.6% in 1997 and 63.5% in 1998. Fields suffering greatest yield loss in 1997 and 1998 were generally those within 600 m of the roosting sites and had about 300 geese grazing on them on areas of around 2 ha in size for about 2 months. By August, geese moved from croplands on to pastures. During October and November, geese once again fed primarily on barley seeds in harvested crops stacked in windrows. Damage by geese to farmers was estimated to be >2.5 and 7% of annual revenue received from barley and wheat farming, in 1997 and 1998, respectively. There are many variables that need to be considered when attempting to quantify and explain damage to cereal crops by Egyptian Geese.

Using patterns of distribution and diversity of Kenyan birds to select and prioritize areas for conservation.

Patterns and environmental correlates of species distributions and richness are identified for Kenyan birds at a quarter degree-square scale. This information is used together with iterative complementarity analyses, which employ species richness, taxonomic dispersion and range-restrictedness, to identify priority areas for possible conservation attention. Bird species apparently not conserved by existing protected areas in Kenya are identified. Six avifaunal zones (and one transitional zone) are distinguished based on distributions of suites of bird species. Variation in biotope diversity (the number of forest and aquatic systems) accounts for 79% of the observed variation in Kenyan bird species richness. Although both rainfall and altitudinal range are significantly correlated with species richness, they only explain an additional 3% of the observed variation. The priority areas identified are situated mainly within highlands and coastal lowlands. Although few priority areas are identified in northern Kenya, this region also constitutes a priority, as it contains a suite of xeric species with habitats that are not represented elsewhere in Kenya. The papyrus yellow warbler, Chloropeta gracilirostris, Williams bush lark, Mirafra williamsi, white-winged dove, Streptopelia reichenowi, and Jubaland weaver, Ploceus dichrocephalus, are identified as endemics or near-endemics that are probably not adequately conserved in Kenya at present.

A multi-locus phylogeny reveals a complex pattern of diversification related to climate and habitat heterogeneity in southern African white-eyes.

The recent, rapid radiation of Zosteropidae, coupled with their high levels of colonizing ability and phenotypic diversity, makes species delimitation within this family problematic. Given these problems, challenges to establish the mechanisms driving diversity and speciation within this group have arisen. Four morphologically distinct southern African Zosterops taxa, with a contentious taxonomic past, provide such a challenge. Here, supplemented with morphological and environmental analytical techniques, a combination of mitochondrial and nuclear markers were analyzed using Bayesian and Likelihood methods to determine their speciation patterns and to establish the phylogenetic relationships of these four morphologically diverse southern African Zosterops taxa. Nearly all individuals were phenotypically diagnosable, even those individuals collected in areas of contact between taxa. Localities where two or more taxa co-occur appear to possess intermediate environmental characteristics. Initial Bayesian and Likelihood mitochondrial DNA analyses and Bayesian structure analyses of the combined nuclear markers indicated levels of hybridization in areas of sympatry. A combined mtDNA and nuclear DNA analysis and a species tree analysis (with hybrids excluded) placed Z. pallidus as sister to the other southern African taxa, with Z. senegalensis the putative sister taxon to a clade comprising Z. capensis and Z. virens. The grouping of taxon-specific sampling localities and the apparent intermediate nature of birds from areas of sympatry points toward an influence of habitat type and the associated climatic conditions in driving Zosterops diversification in southern Africa.