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Maphisa D.H.,South African National Biodiversity Institute | Maphisa D.H.,University of Cape Town | Smit-Robinson H.,BirdLife South Africa | Smit-Robinson H.,Applied Behavioural Ecological and Ecosystem Research Unit ABEERU | And 2 more authors.
Avian Research | Year: 2017

Background: World-wide grassland birds are in decline due to habitat loss and degradation resulting from intensive agricultural practices. Understanding how key grassland habitat attributes determine grassland bird densities is required to make appropriate conservation decisions. We examine drivers of bird densities in a South African grassland area that has been managed for biodiversity conservation with reduced grazing pressure. Methods: We estimated the density of the eight most common grassland bird species encountered in our area to evaluate the effects of recent grassland management changes on the avifauna. We collected data on birds and habitat from the austral summers of 2006/2007, 2007/2008 and 2010/2011. We used hierarchical distance sampling methods to estimate density of birds relative to two main habitat variables, i.e., grass cover and height. In addition, we used regression splines within these distance sampling models as a more flexible description of suitable ranges of grass height and cover for each species. Results: For most species, density is related to grass height and cover as expected. The African Quailfinch (Ortygospiza atricollis) and Common Quail (Coturnix coturnix) preferred relatively short and open grass. The Yellow-breasted Pipit (Anthus chloris), African Pipit (Anthus cinnamomeus) and Red-capped Lark (Calandrella cinerea) preferred short and relatively dense grass, while the Wing-snapping Cisticola (Cisticola ayresii) preferred grass of intermediate height and cover. The Cape Longclaw (Macronyx capensis) and Zitting Cisticola (Cisticola juncidis) preferred tall and dense grass. Our results agree with previous studies that grass height combined with grass cover are the most important habitat features that managers should manipulate in order to increase the density of target species. The regression splines show that the effect of these two habitat variables on density is well described by linear relationships for most species. Conclusions: This study supports previous studies suggesting that grazing and fire are important tools for management to use in order to create a mosaic of grass height and cover that would support high densities of desired species. We suggest that conservation managers of these grasslands combine fire and grazing as management tools to create suitable habitats for grassland birds in general. © 2017 The Author(s).


Collins C.T.,California State University, Long Beach | Anderson M.D.,BirdLife South Africa | Johnson D.N.,156 Golf Road
Ostrich | Year: 2010

The food habits of the Little Swift Apus affinis and African Black Swift Apus barbatus were quantified at Kimberley, Northern Cape province and Makapansgat, Limpopo province, South Africa. As previously documented for other species, both of these swifts took a wide variety of aerial arthropods including spiders as well as 10 orders and 64 families of insects in the combined samples. Little Swift prey items at Kimberley averaged 3.2 mm in body length (SD = 1.6, n = 2 178) and ranged from 1.2 to 16.0 mm. Prey items of African Black Swifts at Kimberley averaged 4.4 mm (SD = 4.1, n = 185) with a range of 0.9 to 15.9 mm, and 2.8 mm (SD = 0.8, n = 2 099) at Makapansgat with a range of 1.2 to 10.8 mm. At Kimberley, African Black Swifts took more (8.3%) larger prey items (>8 mm), such as termites, than Little Swifts (2.3%). As also true of other swifts, both African Black Swifts and Little Swifts took a majority (>90%) of smaller prey items that are abundant in the air column. Mean prey size is significantly correlated with predator body size in Apus and Tachymarptis swifts. © NISC (Pty) Ltd.


PubMed | National Zoological Gardens of South Africa and BirdLife South Africa
Type: | Journal: Scientific reports | Year: 2016

The White-winged Flufftail (Sarothrura ayresi) population is listed as globally Critically Endangered. White-winged Flufftails are only known to occur, with any regularity, in the high-altitude wetlands of South Africa and Ethiopia. Threats to the species include the limited number of suitable breeding sites in Ethiopia and severe habitat degradation and loss both in Ethiopia and South Africa. Toll-like receptors (TLRs) are increasingly being studied in a variety of taxa as a broader approach to determine functional genetic diversity. In this study, we confirm low genetic diversity in the innate immune regions of the White-winged Flufftail similar to that observed in other bird species that have undergone population bottlenecks. Low TLR diversity in White-winged Flufftail indicates that this species is more likely to be threatened by changes to the environment that would potentially expose the species to new diseases. Thus, conservation efforts should be directed towards maintaining pristine habitat for White-winged Flufftail in its current distribution range. To date, no studies on immunogenetic variation in White-winged Flufftail have been conducted and to our knowledge, this is the first study of TLR genetic diversity in a critically endangered species.


News Article | October 29, 2015
Site: news.yahoo.com

An African White Backed Vulture sits on a tree in the Serengeti National Park plains August 18, 2012. REUTERS/Noor Khamis More CAPE TOWN (Reuters) - Africa's vultures are vanishing, according to a report released on Thursday, a situation that could affect human health and livestock since populations of other scavengers such as rats and jackals could rise as a result. The assessment, carried out by conservation group BirdLife International, found that six of Africa's 11 vulture species were at risk of extinction. Deliberate targeting by poachers is one of the reasons as the birds, which circle the sights where they feed, can alert authorities to the carcasses of illegally slain animals. Africa's elephant and rhino populations are being relentlessly poached for their ivory and horns to meet red-hot demand in newly-affluent Asian economies. "Vultures are important. They come in, they clean up and they leave," said Ross Wanless of BirdLife South Africa. "Other scavengers like rats and jackals will eat a carcass and then will go after livestock or become a pest to humans. And if vultures are removed their numbers can increase." Vultures also help to stem the spread of disease on the world's poorest continent by eating carcasses that would otherwise rot. Other reasons behind the decline of the big birds include indiscriminate poisonings and the popularity of vulture parts for traditional medicine. Since the late 1980s, 98 percent of West Africa’s vultures outside protected nature areas have disappeared, while half the population of the Gyps vulture species in Kenya’s Masai Mara park have gone, the report said. In South Africa, cape vultures have declined by 60-70 percent over the past 20-30 years. The assessment was conducted for the International Union for Conservation of Nature's (IUCN) "Red List of Threatened Species", which is considered to be the most authoritative estimate of wild bird and animal populations.


Groom G.,University of Aarhus | Petersen I.K.,University of Aarhus | Anderson M.D.,BirdLife South Africa | Fox A.D.,University of Aarhus
International Journal of Remote Sensing | Year: 2011

Knowing instantaneous locations and numbers of individuals in animal populations is a major requirement for wildlife and conservation ecology. Recent advances in very high spatial resolution digital-imaging systems and in objectbased image-analysis methods offer great potential for developing remote sensing in new application arenas, including direct mapping and counting of birds, mammals and other larger organisms. We present the successful application of an automated object-based image-mapping strategy that has been applied to total mapping, using aerial image data, of Phoeniconaias minor (Lesser Flamingo) individuals at Kamfers Dam, a large perennial lake in central South Africa. The object-based method used quadtree image segmentation and sequential objectbrightness thresholding to identify individual birds with high accuracy (.99% compared to human visual interpretation). Accuracy-assessment results are presented, with discussion of the error factors related to the object-based method and the reference data. An under-estimation by the object-based method of less than 0.5% is indicated. The automated procedure mapped 81 664 Lesser Flamingos at this one site, which is 30% above the most recent estimated size of the entire southern Africa Lesser Flamingo population, indicating a need for further work to reassess this population's size. © 2011 Taylor & Francis.


News Article | October 29, 2015
Site: news.yahoo.com

CAPE TOWN (Reuters) - Africa's vultures are vanishing, according to a report released on Thursday, a situation that could affect human health and livestock since populations of other scavengers such as rats and jackals could rise as a result. The assessment, carried out by conservation group BirdLife International, found that six of Africa's 11 vulture species were at risk of extinction. Deliberate targeting by poachers is one of the reasons as the birds, which circle the sights where they feed, can alert authorities to the carcasses of illegally slain animals. Africa's elephant and rhino populations are being relentlessly poached for their ivory and horns to meet red-hot demand in newly-affluent Asian economies. "Vultures are important. They come in, they clean up and they leave," said Ross Wanless of BirdLife South Africa. "Other scavengers like rats and jackals will eat a carcass and then will go after livestock or become a pest to humans. And if vultures are removed their numbers can increase." Vultures also help to stem the spread of disease on the world's poorest continent by eating carcasses that would otherwise rot. Other reasons behind the decline of the big birds include indiscriminate poisonings and the popularity of vulture parts for traditional medicine. Since the late 1980s, 98 percent of West Africa’s vultures outside protected nature areas have disappeared, while half the population of the Gyps vulture species in Kenya’s Masai Mara park have gone, the report said. In South Africa, cape vultures have declined by 60-70 percent over the past 20-30 years. The assessment was conducted for the International Union for Conservation of Nature's (IUCN) "Red List of Threatened Species", which is considered to be the most authoritative estimate of wild bird and animal populations.


News Article | October 29, 2015
Site: www.reuters.com

The assessment, carried out by conservation group BirdLife International, found that six of Africa's 11 vulture species were at risk of extinction. Deliberate targeting by poachers is one of the reasons as the birds, which circle the sights where they feed, can alert authorities to the carcasses of illegally slain animals. Africa's elephant and rhino populations are being relentlessly poached for their ivory and horns to meet red-hot demand in newly-affluent Asian economies. "Vultures are important. They come in, they clean up and they leave," said Ross Wanless of BirdLife South Africa. "Other scavengers like rats and jackals will eat a carcass and then will go after livestock or become a pest to humans. And if vultures are removed their numbers can increase." Vultures also help to stem the spread of disease on the world's poorest continent by eating carcasses that would otherwise rot. Other reasons behind the decline of the big birds include indiscriminate poisonings and the popularity of vulture parts for traditional medicine. Since the late 1980s, 98 percent of West Africa’s vultures outside protected nature areas have disappeared, while half the population of the Gyps vulture species in Kenya’s Masai Mara park have gone, the report said. In South Africa, cape vultures have declined by 60-70 percent over the past 20-30 years. The assessment was conducted for the International Union for Conservation of Nature's (IUCN) "Red List of Threatened Species", which is considered to be the most authoritative estimate of wild bird and animal populations.


Altwegg R.,South African National Biodiversity Institute | Altwegg R.,University of Cape Town | Doutrelant C.,French National Center for Scientific Research | Anderson M.D.,BirdLife South Africa | And 5 more authors.
Oecologia | Year: 2014

Population trends are determined by gains through reproduction and immigration, and losses through mortality and emigration. These demographic quantities and resulting population dynamics are affected by different external and internal drivers. We examined how these demographic quantities were affected by weather, research-induced disturbance, local density, colony site and year in a metapopulation of 17 sociable weaver (Philetairus socius) colonies over 17 years of study (4 years for reproduction). Most colonies declined, but at different rates. The four demographic quantities were related to different drivers. Survival strongly varied among years and colonies and was positively related to rainfall and negatively related to extreme temperature (together explaining 30 % of variation) and disturbance (measured as number of captures conducted at a colony; 7 %). There was a trend for a positive relationship between reproduction and rainfall (50 %). Movement was mainly related to local density: individuals were more likely to emigrate from small to large colonies and from colonies that were either well below or above their long-term mean. They were more likely to immigrate into colonies that were nearby, and below their mean size. We then quantified the effects of these relationships on metapopulation dynamics using a multi-site matrix projection model. Rainfall was potentially a strong driver of metapopulation dynamics. In addition, field-work disturbance might have contributed to the decline of this metapopulation but could not explain its full magnitude. Hence, through a combination of analytical methods we were able to obtain information on the main drivers affecting dynamics in a declining metapopulation. © 2013 Springer-Verlag Berlin Heidelberg.


Croxall J.,Global Seabird Programme | Small C.,Royal Society for the Protection of Birds | Sullivan B.,Royal Society for the Protection of Birds | Wanless R.,BirdLife South Africa | And 6 more authors.
Marine Ecology Progress Series | Year: 2013

Torres et al. (2013; Mar Ecol Prog Ser 473:275-289) use fine-scale data on tracked locations of one species of albatross and fishing vessels to make a variety of assertions on interactions between them, especially in relation to risk of bycatch. Some of these assertions are incorrect, and we seek to clarify the issues and perspectives involved. We argue that while a fine-scale approach can provide interesting insights into foraging behaviour, large-scale risk analysis is needed because management measures (e.g. for bycatch mitigation) need to operate across all vessels in a fishery and across all seabird species at risk from the fishing operation. In addition, an estimate of 10% time spent in close proximity to vessels cannot be used to infer low bycatch risk alone: such an inference would need comparison to bycatch rate data. The analysis also does not take into account a number of factors known to affect the nature and duration of the association of albatrosses with fishing vessels, which limits the conclusions that can be drawn. However, finescale studies can provide important insight into factors affecting individual bycatch events, and studies at fine and broad scales will be complementary. © Inter-Research 2013.


Maphisa D.H.,South African National Biodiversity Institute | Maphisa D.H.,University of Cape Town | Smit-Robinson H.,BirdLife South Africa | Smit-Robinson H.,Applied Behavioural Ecological and Ecosystem Research Unit ABEERU | And 2 more authors.
PLoS ONE | Year: 2016

Moist high-altitude grasslands in South Africa are renowned for high avifaunal diversity and are priority areas for conservation. Conservation management of these areas conflicts with management for other uses, such as intensive livestock agriculture, which requires annual burning and leads to heavy grazing. Recently the area has become target for water storage schemes and renewable electricity energy projects. There is therefore an urgent need to investigate environmental factors and habitat factors that affect bird species richness in order to optimise management of those areas set aside for conservation. A particularly good opportunity to study these issues arose at Ingula in the eastern South African highaltitude grasslands. An area that had been subject to intense grazing was bought by the national power utility that constructed a pumped storage scheme on part of the land and set aside the rest for bird conservation. Since the new management took over in 2005 the area has been mostly annually burned with relatively little grazing. The new management seeks scientific advice on how to maintain avian species richness of the study area. We collected bird occurrence and vegetation data along random transects between 2006 and 2010 to monitor the impact of the new management, and to study the effect of the habitat changes on bird species richness. To achieve these, we convert bird transect data to presence only data to investigate how bird species richness were related to key transect vegetation attributes under this new grassland management. First we used generalised linear mixed models, to examine changes in vegetation grass height and cover and between burned and unburned habitats. Secondly, we examined how total bird species richness varied across seasons and years. And finally we investigated which habitat vegetation attributes were correlated with species richness of a group of grassland depended bird species only. Transects that were burned showed a larger decrease in vegetation cover compared to transects that were not burned. Grass height increased over time. Bird species richness was highest in summer compared to other seasons and increased over time. Overall bird species richness increased over the three summer surveys but species richness of birds that prefer heavily grazed habitat showed little change over the three years. Changes in bird species richness were best explained by the model with grass height for combined species richness of grassland depended birds but also for birds that prefer heavy grazing when treated alone. On one hand birds that prefer moderate grazing were best explained by a null model. However, overall bird species richness was better positively correlated to grass height than grass cover or dead grass. We conclude that frequent burning alone with relatively reduced grazing led to higher but less dense grass, which benefited some species and disadvantaged others. We suggest that management of this grassland use combination of fire and grazing and leave some areas unburned to accommodates birds of various habitat needs. © 2016 Maphisa et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

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