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Author

D. Du Plessis

Bio: D. Du Plessis is an academic researcher. The author has contributed to research in topics: Eagle & National park. The author has an hindex of 1, co-authored 1 publications receiving 10 citations.

Papers
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Journal ArticleDOI
01 Dec 1996-Ostrich
TL;DR: Herholdt, JJ, Kemp, AC & Du Plessis, D 1996 Aspects of the breeding status and ecology of the Bateleur and Tawny Eagle in the Kalahari Gemsbok National Park Ostrich 67:126-137 The nesting s
Abstract: Herholdt, JJ, Kemp, AC & Du Plessis, D 1996 Aspects of the breeding status and ecology of the Bateleur and Tawny Eagle in the Kalahari Gemsbok National Park Ostrich 67:126-137 The nesting s

10 citations


Cited by
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Journal ArticleDOI
01 Jul 2003-Oikos
TL;DR: This paper investigated the potential impact of precipitation variation caused by climate change on raptors in arid savanna using the tawny eagle (Aquila rapax) in the southern Kalahari as a case study.
Abstract: Arid savannas are regarded as one of the ecosystems most likely to be affected by climate change. In these dry conditions, even top predators like raptors are affected by water availability and precipitation. However, few research initiatives have addressed the question of how climate change will affect population dynamics and extinction risk of particular species in arid ecosystems. Here, we use an individual-oriented modeling approach to conduct experiments on the population dynamics of long lived raptors. We investigate the potential impact of precipitation variation caused by climate change on raptors in arid savanna using the tawny eagle (Aquila rapax) in the southern Kalahari as a case study. We simulated various modifications of precipitation scenarios predicted for climate change, such as lowered annual precipitation mean, increased inter-annual variation and increased auto-correlation in precipitation. We found a high impact of these modifications on extinction risk of tawny eagles, with reduced population persistence in most cases. Decreased mean annual precipitation and increased inter-annual variation both caused dramatic decreases in population persistence. Increased auto-correlation in precipitation led only to slightly accelerated extinction of simulated populations. Finally, for various patterns of periodically fluctuating precipitation, we found both increased and decreased population persistence. In summary, our results suggest that the impacts on raptor population dynamics and survival caused by climate change in arid savannas will be great. We emphasize that even if under climate change the mean annual precipitation remains constant but the inter-annual variation increases the persistence of raptor populations in arid savannas will decrease considerably. This suggests a new dimension of climate change driven impacts on population persistence and consequently on biodiversity. However, more investigations on particular species and/or species groups are needed to increase our understanding of how climate change will impact population dynamics and how this will influence species diversity and biodiversity.

66 citations

Journal ArticleDOI
TL;DR: The rapid decline of scavenging birds, especially vultures, in central Kenya warrants additional population monitoring to understand whether declines are local or regional, and to elucidate causes of population decreases.
Abstract: Raptors were monitored monthly over a three-year period in a protected area in central Kenya. The number of raptors declined more than 40% per year. Scavenging birds accounted for most of the decline; sightings decreased by 70% during our surveys, although these declines were not statistically significant. During the time of the study, the overall populations of large wild herbivores showed little change, whereas domestic herbivores, particularly sheep and goats, increased markedly, suggesting that food limitation was not the cause of the vulture declines at the study site. Possible causes of raptor decline include the consumption of poisoned baits, which are placed by pastoralists to kill large predators that attack livestock. Scavenging birds provide one of the most important yet underappreciated ecosystem services of any avian group. The rapid decline of scavenging birds, especially vultures, in central Kenya warrants additional population monitoring to understand whether declines are local or...

47 citations

Journal ArticleDOI
TL;DR: In 2015 and 2016, this paper repeated road transects for raptors across northern Botswana that were first conducted in 1991 and 1995, and explored changes in abundance of 29 species.

28 citations

Journal ArticleDOI
TL;DR: This paper examined the relationship between the distribution of Martial Eagles Polemaetus bellicosus (and other large eagle species) breeding on electricity transmission pylons in the central and southwestern Karoo, South Africa, and the general environmental health of commercially managed farmland in that region.

25 citations

Journal ArticleDOI
01 Dec 2004-Ostrich
TL;DR: In this article, global change challenges the Tawny Eagle (Aquila rapax): modelling extinction risk with respect to predicted climate and land use changes, and the authors propose a model to predict extinction risk of the Ternus ternus.
Abstract: (2004). Global change challenges the Tawny Eagle (Aquila rapax): modelling extinction risk with respect to predicted climate and land use changes. Ostrich: Vol. 75, No. 4, pp. 204-210.

19 citations