The Prevalence and Intensity of Louse (Phthiraptera, Mallophaga) and Tick (Acarina: Ixodidae) Infestation of Birds in South African Grasslands
A total of 270 birds represented by 12 species were examined for the presence of lice and ticks. Birds were collected in South African grasslands. Extensity of louse and tick infestation ranged from 10% to 80% and from 3% to 33% respectively. Average number of lice per host species ranged from 1 to 15, while average number of ticks per host species ranged from 1 to 5. Only single specimens (0.4%) were heavily parasited by lice and ticks respectively. Lice infested birds more often during the dry season, while ticks infested birds mainly during the rain season.
Temperature and rainfall related to altitudinal gradients influence ecological and evolutionary responses of organisms to physical factors. In this study, the line transect method was used during the years 1996–2001 to compare resident (potentially breeding) bird communities in three altitudinal divisions in Highveld/Drakensberg grasslands in Lesotho: lowlands (< 1700 m a. s. l.), foothills (1700–2200 m a. s. l.) and highlands (> 2200 m a. s. l.). In total, 105 resident species were recorded. The total number of species recorded in lowlands was higher than that in highlands and foothills, but this difference was not statistically significant. The highland and foothill did not differ in numbers of species. A group of five species dominated at all three sites, and the proportion of dominant species in relation to the whole assemblage was very similar. The composition of the dominant group (species with more than 5 % of pairs) and the group of species most often encountered (in more than 80 % of transects) was, however, different. Only two species, Cape Canary Serinuscanicollis and Karoo Prinia Priniamaculosa were dominant in all three study areas, and just one species, the Cape Bunting Emberizacapensis, was dominant in two plots. Similarly, only two species, the Cape Turtle-Dove Streptopelia capicola and Cape Canary had a high frequency of occurrence in all three study areas, and two otherspecies, theKaroo Prinia and Cape Bunting — in two study areas. Simpson’s Diversity Index was strikingly the same (S = 0.96) for all three avian assemblages (lowland, foothill and highland) investigated. However, proportions of breeding pairs of some congeneric species were found to change with the altitude. The granivores were more common (44–45 %) in the foothills and highlands than in lowlands (36%), while insectivores were more common in the highlands (50 %) than in foothills and lowlands (36–37 %). In general, avifauna is relatively diverse and unique in the Highveld/Drakensberg grasslands. Results presented here provide data for further investigation of the effect of the supposed climate warming on the diversity and structure of avian communities.
Studies were conducted by means of the Line Transect Method in late rainy season (March), in the middle of dry season (July) and at beginning of rainy season (November).Th e total length of all transects was c. 11 km. In total, 70 resident and 13 nonresidentspecies were recorded. Th e number of species in dry season was significantly lower than in rainy season (x2-test: 14.1; p < 0.01). Th e highly significant seasonal differences in abundance were recorded for the following species: Streptopelia senegalensis, Streptopelia capicola, Uraeginthus angolensis, Cisticola juncidis, Upupa africana, Cynniris mariquensis, and Numida meleagris. In overall, five species have been classified as dominants: Streptopelia senegalensis, Streptopelia capicola, Uraeginthus angolensis, Plocepasser mahali and Cypsiurus parvus. They comprised together 43.9 %. Significant variations in the dominance structure between the wet and dry season have been evidenced. Granivores were much more numerous in the dry than in the wet season, while for the insectivores the reverse was true. Although Sorensen Coefficient was much the same between all three seasons, the Shannon’s Diversity Index was lower in July than in March and November.
Month-to-month changes in avian assembages are considerable in forest habitats. In this study such changes were studied by means of the line transect method (eight transect with total length of 77.7 km) in lowland coniferous forest in SW Poland (dominant forest type in Central European Plain), in three consecutive spring months: April, May and June. Shannon’s diversity index varied between 1.31 and 2.25 in particular month, while Simpson’s diversity index and Pielou’s evenness index were almost identical everywhere: H′ = 0.92-0.93 and J′ = 0.74-0.78, respectively. In overall, the differences in mean densities of breeding species between three months on all transects pooled were not statistically significant, as were also not statistically significant such differences on particular transects. Month-to-month variations in densities in all transects pooled were statistically significant in the case of 26 out of 54 species (48.1 %). Month-to-month changes in population densities recorded on transects, only partly conform to the arrival patterns. Two counts, instead of three, would sufficed for precise estimation of bird population densities in Central European lowland pine forests: one count should be conducted in April, to register mainly resident species, and the second one in May to count mainly the migrant species.
During the year 1999-2001, avian assemblages associated with cliffs and bushy vegetation of the Clarens Formation have been quantified by means of the line transect method (total length of transects - 107 km) in Lesotho lowlands. In total, 80 species resident in these habitats were recorded. Overall, six species were classified as dominants: Serinus canicollis, Prinia maculosa, Streptopelia senegalensis, Emberiza tahapisi, Emberiza capensis and Cisticola fulvicapilla. Together they comprised 41.4 % of all breeding pairs. Ten other species were classified as subdominants (33.9 %). Granivores were the most numerous feeding guild (31 species; 48.0 % of all pairs), followed by insectivores (27 species; 32.3 %) and frugivores (11 species; 17.4 %). The most numerous nesting guild were shrub/tree nesting birds (47.2 %). Proportions for some congereric species were calculated. The bushy vegetation is characterized by high species diversity and relatively high population densities of some species.
The mapping method was employed to study avian community structure in relation to rainfall in a town suburb in Highveld grassland in southern Africa. Studies were conducted in two breeding seasons: 1998, with dry spring; and 2001, with close to average spring rainfall. The total rainfall in 1998 was 1254 mm, while in 2001 it was 1445 mm, in both years much above the long-term annual average (866 mm). The avian community remained remarkably similar in both years, both in respect to the number of species (44 in 1998 and 53 in 2001), and dominance relationships. The Simpson’s Diversity Index was high and also very similar in 1998 and 2001 (D = 0.91; 0.93 respectively). In all years, dominant species included the Laughing Dove, Grey-headed Sparrow, Speckled Dove, Cape Turtle-Dove and Common Fiscal. The Southern Red Bishop in 2001 was also in the group of dominants. Significant differences were noted in the overall density of all birds, but contrary to expectation density was higher in 1998, with lower rainfall, than in 2001, with higher rainfall. The proportions of nesting and feeding guilds were similar in both years compared, except for the granivores, which were proportionally more common in 1998 than in 2001. This difference was mainly due to the Laughing Dove and Grey-headed Sparrow. Generally, it appears that the suburban avian community is more stable and more diverse than neighbouring communities in the natural habitats.
In 1998 Przewalski’s horses have been introduced in the Chernobyl exclusion zone (CEZ), N Ukraine. They live in the zone under natural conditions. No anthelminthic treatment to these introduced horses has been applied to date. In this same area, 19 domestic horses were also stabled by some peasants. Eighteen years after the Chernobyl nuclear disaster, and five years after this introduction, the diagnostic dehelminthisation method has been applied both to the Przewalski’s horses (n = 21) and the domestic horses (n = 6). In addition, in one Przewalski’s and one domestic horse helmith fauna was surveyed using the post-mortem method. A total of 29 and 19 helminth species has been recorded in the Przewalski’s and domestic horses respectively. Only six helminth species were common for the two horse species compared. Species from the family Strongylidae constituted the dominant helminth group. Four cyathostomine species (Cyathostomum catinatum; Cylicostephanus minutus, C. longibursatus, Cylicocyclus nassatus) formed the majority of helminth parasites both in the Przewalski’s and domestic horses. Our findings suggest that the CEZ has no effect on the species diversity of helminth fauna parasiting Przewalski’s horses, neither it has an effect on the prevalence and intensity of parasite infestation. Behavioural and ecological studies also support the lack of such effect.
A study on the seasonal variation in population structure of seven (7) ungulate species, African buffalo (Syncerus caffer), eland (Tragelaphus oryx), giraffe (Giraffa camelopardalis), oryx (Oryx gazella), sable (Hippotragus niger), roan antelope (Hippotragus equinus) and the greater kudu (Tragelaphus strepsiceros) was carried out using the field census approach during the wet (February– April) and dry (July–September) season, and a water hole census (September) at seven waterholes in the Waterberg National Park, Namibia. Male warthog, oryx and black rhino on average comprised about 40 % of the population, whereas male sable, roan antelope, eland and buffalo comprised 30 % of the population. Male kudu and male white rhino comprised 20 % of the sex structure of the population, whereas male giraffe comprised more than 50 % of population. Age structure was dominated by adults, with 60 % of the total population in warthog, sable, eland and the white rhino, and 70 % in kudu, roan, buffalo, giraffe and black rhino on average. Oryx had the highest number of adults, with only 10 % of the population comprised of juveniles. Larger herds were observed during the wet season and smaller herds during the dry season. Animals were observed more abundantly in three of the vegetation types (Terminalia sericea — Melhania acuminata vegetation, Terminalia sericea — Thesium megalocarpum, Terminalia sericea — Blepharis integrifolia), with lower abundances in the rock-inhabiting Peltophorum africanum during both seasons.