Avian Diversity along a Precipitation Gradient in Southern Africa

Roads may have negative or positive effects on wildlife. I surveyed birds along a c. 21 km transect alongside a road from Katima Mulilo to Ngoma bridge in the Zambezi Region, north-eastern Namibia, and on a second transect (control) parallel to the first one and 200–400 m away from the road. The habitat is Kalahari Woodland, partly transformed to cultivated fields. The number of bird species was similar on both transects (56 vs. 48 species; x2 = 0.62, p > 0.05), but the number of breeding pairs (overall population density) was much higher away from the road than close to it (409 vs. 283 pairs; x2 = 22.9, p < 0.01). The Shannon’s Diversity Index was very similar, while Pielou’s Evenness Index was identical in both transects compared. Five species (Blue Waxbill, Burchell’s Starling, Cape Turtle Dove, Fork-tailed Drongo and Grey-headed Sparrow) were dominant on both transects, while the African Grey Hornbill was dominant only on the transect away from the road, whereas the Red-billed Hornbill and Grey Go-away-bird were dominant only close to the road. Four species (African Grey Hornbill, Cape Turtle Dove, Meyer’s Parrot and White-browed Scrub Robin) had population densities significantly higher on the transect away from the road than close to it. However, population densities of nine other species did not differ significantly between the two transects. In general, the avian communities along and away from the road were similar, probably because traffic volume was rather low and the land cover on both transects was similar in terms of natural vegetation and degree of transformation.

The Zambezian Baikiaea woodlands fall entirely within the Kalahari Woodland biome, a subset of savanna. In 2015, the line transect method was employed to study avian assemblages associated with Zambezian Baikiaea. In total, 10 transects were designed along a straight 12 km long line, so that each transect was 1.2 km long. A total of 88 species represented by 1190 pairs were recorded. On average, there were 42.9 species per transect. The overall density was 35.8 pairs/km, ranging from 29.2 to 44.2 on particular transects. Overall, Streptopelia capicola was the only dominant species. It was also the only species recorded as dominant on all the transects. The following other species were recorded as dominant: Cercotrichas leucophrys, Laniarius aethiopicus, Turtur chalcospilos, Dicrurus adsimilis, Lamprotornis nitens, Upupa africana, Apalis flavida, Ploceus velatus, Tchagra australis and Numida meleagris. The proportion of dominant species (cumulative dominance) varied from 18.9 to 37.7 (x = 28.5; n =...

During the years 1996-2001, the line transect method has been employed to assess the species composition, dominance structure and relative abundance of birds resident in traditional farmlands, in the lowlands (10 transects with the total length of 43.9 km) and foothills (10 transects with the total length of transects 46.5 km) of Lesotho, southern Africa. This has been done to show the role of this farming in biodiversity conservation. A total of 76 resident species have been recorded in farmlands of Lesotho, 62 species in the lowlands and 53 species in the foothills. In the lowland farmlands the dominant group was composed of 6 species, namely the Prinia, Cape Bunting, Cinnamon-breasted Bunting, Cape Canary, Neddicky and Common Quail (35.8 %); in the foothills the group was composed 5 species: Karoo Prinia, Cape-turtle Dove, Laughing Dove, Cape Bunting and Cape Canary (35.9 %). Eighteen species bred in significantly different densities in lowlands and foothills. While insectivorous birds were more numerous in the lowland than foothill, the reverse was true with granivorous birds. Those two guilds comprised together 78% and 83% in the lowland and foothill respectively. The proportion of species in each guild was similar. In the lowland farmland the following eight species were more common that in the foothill farmlands, while in foothill farmland 10 species were more numerous than in lowland farmland. Species diversity and evenness were strikingly high and similar in lowlands and foothills, although Sorensen Similarity Index between these two areas was low (I = 0.44). Both species diversity and structure of dominance in avian communities in Lesotho farmlands indicate that the traditional farming play a positive role in biodiversity conservation.

Comparing the numbers of four bird species, House Sparrow, Cape Glossy Starling, Laughing Doves and Cape Turtle Dove in Gauteng and Limpopo Three of the species showed significant declines in one or both province. The Cape Glossy Starlings was the only specie to show an increase in both provinces.

Cross-basin heterogeneity in lanternfish (family Myctophidae) assemblages and isotopic niches (δ13C and δ15N) in the southern Tasman Sea abyssal basin

Birds show phylogenetic variation in the relative importance of respiratory versus cutaneous evaporation, but the consequences for heat tolerance and evaporative cooling capacity remain unclear. We measured evaporative water loss (EWL), resting metabolic rate (RMR) and body temperature (Tb) in four arid-zone columbids from southern Africa [Namaqua dove (Oena capensis, ∼37 g), laughing dove (Spilopelia senegalensis, ∼89 g) and Cape turtle dove (Streptopelia capicola, ∼148 g)] and Australia [crested pigeon (Ocyphaps lophotes), ∼186 g] at air temperatures (Ta) of up to 62°C. There was no clear relationship between body mass and maximum Ta tolerated during acute heat exposure. Maximum Tb at very high Ta was 43.1±1.0, 43.7±0.8, 44.7±0.3 and 44.3±0.8°C in Namaqua doves, laughing doves, Cape turtle doves and crested pigeons, respectively. In all four species, RMR increased significantly at Ta above thermoneutrality, but the increases were relatively modest with RMR at Ta=56°C being 32, 60, 99 and 11% higher, respectively, than at Ta=35°C. At the highest Ta values reached, evaporative heat loss was equivalent to 466, 227, 230 and 275% of metabolic heat production. The maximum ratio of evaporative heat loss to metabolic production observed in Namaqua doves, 4.66, exceeds by a substantial margin previous values reported for birds. Our results support the notion that cutaneous evaporation provides a highly efficient mechanism of heat dissipation and an enhanced ability to tolerate extremely high Ta.

The line transect method has been employed to assess species diversity, population densities and community structure of birds breeding in a mosaic of Kalahari Woodland and farmland, NE Namibia. The transect, 4.5 km long, was surveyed in 2014 and 2015. The total annual rainfall in 2014 was much higher than in 2015 (427 mm vs. 262 mm). In total, 40 breeding species in 2014, and 46 in 2015 were recorded. Six species were dominant in 2014 (Cape Turtle Dove, Laughing Dove, Emerald-spotted Dove, Blue Waxbill, and White-browed Scrub Robin) and only three species in 2015 (Cape Turtle Dove and Blue Waxbill and Yellow-fronted Canary). Although the cumulative dominance in 2014 almost doubled that in 2015, the Community Index in both years was almost identical. Also diversity indices and evenness index were very similar in both years compared. Granivorous birds were the most numerous feeding guild. Their contribution was similar in 2014 and 2015 (46.7 % vs. 43.4 %). Two other feeding guilds, insectivores and frugivores, comprised together more than 50 % in both years. The number of bird species and species diversity were not influenced by the differential rainfall. However, contrary to expectations, population densities of most bird species (at least the more numerous ones) were higher in the year with lower than in the year with higher rainfall. The number of species and species diversity was similar in the farmland and in neighbouring Kalahari Woodland in a pristine stage. However, population densities of most species were lower in the farmland than in the pristine woodland.

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.

One of the most persistent rain-making events over East Asia is the development of an early summer monsoon trough (Mei-Yu) which extends from southeastern China to southern Japan. This work studies the structure and vorticity budget of a Mei-Yu system for the period 10–15 June 1975. Subjectively analyzed grid-point data are time composited with respect to the trough axis along three cross sections over southeastern China (western section), southern East China Sea (central section) and southern Japan (eastern section), respectively, during the mature and decaying stages of the trough. The results indicate that the structure of the eastern and central sections resembles a typical midlatitude baroclinic front with strong vertical tilt toward an upper level cold core and a strong horizontal temperature gradient. On the other band, the western section resembles a semitropical disturbance with an equivalent barotropic, warm core structure, a weak horizontal temperature gradient, and a rather strong horizontal wind shear in the lower troposphere. Cumulus convection activity south of the 850 mb trough is significant in all three sections and contributes substantially to the thermally direct secondary circulation, but the large-scale organizing mechanism differs from one section to another. In the eastern and central sections it is mainly due to differential vorticity advection while in the western section it is due to Ekman pumping (CISK). The generation of cyclonic vorticity is counteracted by cumulus damping in the eastern section and by boundary layer friction in the mountainous western section.

Lithostratigraphy, microfacies and paleogeography of the shallow marine Middle Limestone Member of the Early Eocene Rusayl Formation, Oman: Relationship to the Early Eocene Climatic Optimum, sea-level changes and regional uplift

We conducted transect surveys in urban Pretoria, South Africa, to document interspecific interactions involving the invasive Common Myna Acridotheres tristis and coexisting species. During 90 standardised transect surveys across three suburban sites from April to August 2022 (outside the main breeding season for many bird species), we recorded 36 interspecific interactions between Common Mynas and other birds. Common Mynas were observed chasing or being aggressive towards other birds such as sparrows (Passer diffusus, P. domesticus) and doves (Streptopelia capicola, Spilopelia senegalensis). Of these encounters, 26 (72%, 95% CI: 56–84%) involved aggression, with Common Mynas initiating 86% of aggressive incidents. In most aggressive incidents, the other bird fled; only larger species (Cape Starlings Lamprotornis nitens) successfully retaliated. Such aggression may facilitate the displacement of native and non-native species from feeding sites or nesting areas. These findings provide evidence for interference competition by Common Mynas in South African urban environments and highlight the need for targeted management strategies to protect native bird communities.

Purpose: the studies of the Proletarskiy reservoir is to use the Novo-Manych dam in regulating the operation of the western and eastern sections with a water regulating structure between them. Materials and methods: the issues on use and regulation of water resources of the Proletarsk reservoir are considered, including the Novo-Manych dam, which divides the reservoir into the western and eastern sections. Results. The western section of the Proletarskiy reservoir is located between the Proletarskiy hydroelectric complex and the Novo-Manych dam and is a stretch of about 20 km. Under normal operating conditions, water flows from the western section to the eastern one through the water regulating structure in the Novo-Manych dam. At the same time, the main amount of water enters the western section along the river Egorlyk, it is discharged through the drain of the Proletarskiy hydroelectric dam into the Veselovskoye reservoir. The eastern section of the Proletarskiy reservoir is limited by the Novo-Manych dam on the western side and a blind dam on the eastern side. According to the initial project, the water resources of the Proletarskiy reservoir were used for shipping, irrigation, fisheries, and hydropower. The actual use of the reservoir's water resources for navigation is practically absent, irrigation is not performed, the fishery has lost its importance, and the hydropower industry has been out of service. Only recreation is used: the sanatorium “Manych”, about 30 hunting farms, the “Rostovsky” and “Chernye Zemli” reserves, the natural monument “Primanychskaya steppe”. The network of reservoirs and Manych-Gudilo lake is a wetland of international importance as a habitat for waterfowl. Conclusions. The issues of the use and regulation of water resources of the Proletarskiy reservoir and the Novo-Manych dam, dividing the reservoir into the western and eastern sections are considered.

Two seasons of the year, dry and wet, are characteristic climate elements in southern Africa. Caused by differential precipitation, this seasonality induces seasonal variation in primary and secondary production. Birds are also affected. An avian community was studied in dry and wet seasons in an urbanised habitat of Tsumeb, a town situated in northern Namibia. Although both the species richness and the general dominance structure were similar in the dry and wet seasons, the avian community differed significantly in terms of population density of more common species in this town. Sörensen similarity index between the dry and wet seasons was low (I = 0.68). As expected, among granivorous species, the Laughing Dove (Streptopelia senegalensis), the Rosy-faced Parrot (Agapornis roseicollis), the House Sparrow (Passer domesticus), and the Southern Masked Weaver (Ploceus velatus) were much more numerous in the dry than in the wet season. However, contrary to expectation, the Blue Waxbill (Uraeginthus angolensis) was much more numerous in the wet than in the dry season. The Red-eyed Bulbul (Pycnonotus nigricans) was more common in the wet season, but other frugivorous species, the Red-faced Mousebird (Urocolius indicus), was more numerous in the dry than in the wet season.

In order to examine the spatial variability of the aerosol characteristics across the Brahmaputra valley, a land campaign was conducted during late winter (February 3–March 2) 2011. Measurements of particulate matter (PM, PM10, PM2.5) and black carbon (BC) concentrations were made onboard an interior redesigned vehicle. The length of the campaign trail stretched about 700 km, covering the longitude belt of 89.97°–95.55°E and latitude belt of 26.1°–27.6°N, comprising 13 measurement locations. The valley is divided into three sectors longitudinally: western sector (R1: 89.97°–91.75°E), middle sector (R2: 92.5°–94.01°E) and eastern sector (R3: 94.63°–95.55°E). Spatial heterogeneity in aerosol distribution has been observed with higher PM10 and PM2.5 concentrations at the western and middle sectors compared to the eastern sector. The locations in the western sector are found to be rich in BC compared to the other two sectors and there is a gradual decrease in BC concentrations from west to east of the Brahmaputra valley. Two hotspots within the western and middle sectors with high PM and BC concentrations have been identified. The associated physico-optical parameters of PM reveal abundance of PM2.5 aerosols along the entire valley. High population density in the western and middle sectors, together with the contribution of remote aerosols, leads to higher anthropogenic aerosols over those regions. Spectral Radiation-Transport Model for Aerosol Species (SPRINTARS) slightly underestimates the measured PM10 and PM2.5 at the eastern sector while the model overestimates the measurements at a number of locations in the western sector. In general, BC is underestimated by the model. The variation of BC within the campaign trail has not been adequately captured by the model leading to higher variance in the western locations as compared to the middle and eastern locations.

The paper analytically discusses certain palaeoecological criteria in the reconstruction of Lower Miocene (Aquitanian-Burdigalian) palaeobiogeography of the Indian subcontinent. The period is characterised by major marine transgressions and a prolific marine invertebrate and terrestrial vertebrate faunas. Faunal affinities of molluscs from western (Sind-Baluchistan) and eastern (Garo Hills) sectors are distinct and different. Molluscs of Garo Hills show affinity to Burmese species, whereas Sind-Baluchistan species shows similarity to that of the Mediterranean region. Marine molluscs resemble with the present-day taxa of the Arabian Sea and Bay of Bengal, where more than 35% species are common. This similarity is also evidenced by marine elasmobranchs, where approximately 33% species and 86% genera are similar to that of the Recent taxa. Terrestrial mammals show an intermingling of southern U.S.S.R. and African forms along with the presence of probably some groups belonging to the Indian subcontinent. Angiosperms are the dominant group. The Lower Miocene floras of the eastern and the western sectors are entirely different. The palm,Sabal major andPinus are reported from various localities. The climate in the western sector and South India was tropical, whereas in the eastern sector, it was variable. The Lower Miocene period is also marked by the contraction of Sindhu Sea, Bangla Sea and the Burmese Gulf southwards resulting in the final disappearance of the sea by the Pliocene.