High productivity by Fish Eagles on a polluted dam near Harare

Mundy, P.J. & Couto, J.T. 2000. High productivity by Fish Eagles on a polluted dam near Harare. Ostrich 71 (1 & 2): 11–14.

Lake Chivero, in the Robert McIlwaine Recreational Park west of Harare, is the capital city's main reservoir of drinking water. It has been the subject of five surveys for pesticides and/or heavy metals in the period 1974–1995. The (geometric) average DDE residue level in seven Fish Eagle eggs collected in 1980 was 53 ppm dry weight. By 1995, DDT levels had considerably declined. There are now five pairs of Fish Eagles on Lake Chivero (1996), at a very low density of 14.8 km shoreline per pair. In the 14-year period, 1984–1997, 40 pair-occupations have been found and inspected, which produced 64 fledglings. One nest had fledglings in 11 years, and on three occasions broods of three were produced from it. A fourth brood of three was produced at another nest. The dam receives treated sewage effluent from the city and is now highly eutrophic; this has contributed to the eagles' breeding performance.     

Structural patterns of Lepidoptera galls and the case of Andescecidium parrai (Cecidosidae) galls on Schinus polygama (Anacardiaceae)

Journal of Plant Research - Gall anatomical and metabolic peculiarities are determined by the feeding habit of the gall inducer, but develop under the constraints of the host plants. The chewing...     

Ending AIDS as a public health threat by 2030: Time to reset targets for 2025

Paul De Lay and co-authors introduce a Collection on the design of targets for ending the AIDS epidemic.     

Hyperepilithics—An overlooked life form of vascular plants on tropical vertical rock walls

Vascular epiphytes are a characteristic life form in many tropical regions and often occur growing on bare rocks. South America has the highest diversity. Here, we describe a neglected life form: hyperepilithics adapted and restricted to growing on vertical (inclination above 70°) and bare rock walls without having roots intruding the substrate. Hyperepilithics are in particular present on Brazilian inselbergs and dominated by highly specialized Bromeliaceae, mainly of the genera Stigmatodon, Tillandsia and Alcantarea, whereas Orchidaceae surprisingly has a low representation. An overview of this habitat, the life form hyperepilithics and a comparison with similar paleotropical habitats (mainly inselbergs in Western/Eastern Africa and India) are provided. Attention is drawn to hyperepilithics as a most promising and not yet exploited source for a sustainable urban ‘vertical gardening’, for example in tropical megacities.     

Reproductive pattern of Brachionus calyciflorus Pallas at different food concentrations

Laboratory populations of Brachionus calyciflorus were grownat different food levels, to determine whether B.calyafloruswas capable of varying its reproductive pattern, according tothe concentration of available food to maintain a high rateof population growth The volume of eggs borne by females wasmeasured, and the carbohydrate content of the animals was analysed.When food was abundant, egg volume and carbohydrate contentwere low Since small neonates can easily become adults becauseof the good food conditions, B calyciflorus utilized its energyto increase the number of offspring At low food concentrations,there was an important increase in egg volume and carbohydratecontent As egg numbers decreased, then B calyciflorus then appearedto use its energy to increase neonate size. Tins tendency wasmaintained down to a threshold concentration, below which eggvolume and carbohydrate content diminished again due to insufficientfood