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Game Reserve (game + reserve)

Distribution by Scientific Domains

Life Sciences	81%

Kinds of Game Reserve

private game reserve

Selected Abstracts

Acoustic Features of Female Chacma Baboon Barks

ETHOLOGY, Issue 1 2001
Julia Fischer
We studied variation in the loud barks of free-ranging female chacma baboons (Papio cynocephalus ursinus) with respect to context, predator type, and individuality over an 18-month period in the Moremi Game Reserve, Botswana. To examine acoustic differences in relation to these variables, we extracted a suite of acoustic parameters from digitized calls and applied discriminant function analyses. The barks constitute a graded continuum, ranging from a tonal, harmonically rich call into a call with a more noisy, harsh structure. Tonal barks are typically given when the signaler is at risk of losing contact with the group or when a mother and infant have become separated (contact barks). The harsher variants are given in response to large predators (alarm barks). However, there are also intermediate forms between the two subtypes which may occur in both situations. This finding is not due to an overlap of individuals' distinct distributions but can be replicated within individuals. Within the alarm bark category, there are significant differences between calls given in response to mammalian carnivores and those given in response to crocodiles. Again, there are intermediate variants. Both alarm call types are equally different from contact barks, indicating that the calls vary along different dimensions. Finally, there are consistent, significant differences among different individuals' calls. However, individual identity in one call type cannot directly be inferred from knowledge of the individuals' call characteristics in the other. In sum, the barks of female baboons potentially provide rich information to the recipients of these signals. The extent to which baboons discriminate between alarm and contact barks, and classify calls according to context and/or acoustic similarity will be described in a subsequent paper. [source]

Large predators and their prey in a southern African savanna: a predator's size determines its prey size range

JOURNAL OF ANIMAL ECOLOGY, Issue 3 2004
Frans G. T. Radloff
Summary 1A long-term (13-year) data set, based on > 4000 kills, was used to test whether a sympatric group of large predators adheres to the theoretical predictions that (1) mean prey body size and (2) prey diversity increase as functions of predator body size. 2All kills observed by safari guides are documented routinely in Mala Mala Private Game Reserve, South Africa. We analysed these records for lion (Panthera leo, Linnaeus), leopard (Panthera pardus, Linnaeus), cheetah (Acinonyx jubatus, Schreber) and African wild dog (Lycaon pictus, Temminck). Males and females of the sexually dimorphic felid species were treated as functionally distinct predator types. Prey types were classified by species, sex and age class. 3Prey profiles were compared among predator types in terms of richness and evenness to consider how both the range of prey types used and the dominance of particular prey types within each range may be influenced by predator size. No significant size-dependent relationships were found, so factors separate from or additional to body size must explain variation in prey diversity across sympatric predators. 4A statistically strong relationship was found between mean prey mass and predator mass (r2 = 0·86, P= 0·002), although pairwise comparisons showed that most predators killed similar prey despite wide differences in predator size. Also, minimum prey mass was independent of predator mass while maximum prey mass was strongly dependent on predator mass (r2 = 0·71, P= 0·017). The ecological significance is that larger predators do not specialize on larger prey, but exploit a wider range of prey sizes. [source]

The impact of cattle ranching on large-scale vegetation patterns in a coastal savanna in Tanzania

JOURNAL OF APPLIED ECOLOGY, Issue 3 2003
M. W. Tobler
Summary 1The success of large-scale cattle ranching in African savanna vegetation has often been limited by problems of bush encroachment and disease (in particular trypanosomiasis spread by tsetse flies). Mkwaja Ranch, occupying an area of 462 km2 on the coast of Tanzania, is a recent example of a large ranching enterprise that failed within the savanna environment. It was closed in 2000 after 48 years of operation. In this paper we describe the main vegetation types of the area (excluding closed forest vegetation) and relate their patterns of distribution to the former use of the ranch for cattle. 2The study area comprised the former ranch and parts of the adjacent Saadani Game Reserve, which had not been grazed by cattle for many years and had never been used for large-scale ranching. Following field surveys, 15 distinct types of grassland and bush vegetation were defined and a vegetation map was created using a Landsat TM satellite image. A multispectral classification using the maximum likelihood algorithm gave good results and enabled all 15 vegetation types to be distinguished on the map. 3Two main spatial trends were detected in the vegetation. One was a large-scale decrease in the cover of bushland from the most intensively used parts of the ranch through more extensively used areas to the game reserve; this trend was attributed to differences in management history as well as to climatic and topographic factors. A second trend was a radial vegetation pattern associated with the enclosures where cattle were herded at night. High amounts of three bushland types [dominated by (i) Acacia zanzibarica, (ii) Dichrostachys cinerea, Acacia nilotica or Acacia mellifera and (iii) Terminalia spinosa] occurred in a zone between 300 and 2500 m from the paddocks, with a peak in bush density at about 900 m (mean value for 18 paddocks). In contrast, bushland dominated by Hyphaene compressa was scarce close to the paddocks and became more abundant with distance. There was also a radial trend in the grassland communities: close to the paddocks there was short grass vegetation containing many ruderals and invasive weedy species, while the tall grassland types with species such as Hyperthelia dissoluta and Cymbopogon caesius occurred further away in the areas less affected by cattle. 4Synthesis and applications. The intensive modern livestock ranching as practised on Mkwaja Ranch proved to be unsustainable both economically and ecologically. In the end, the biggest problem faced by the ranch managers was not controlling disease, as had originally been feared, but preventing the spread of bush on pasture land. The results of our study demonstrate just how severe the problem of bush encroachment was, especially in areas close to paddocks. An important lesson for management is that grazing patterns need to be taken into consideration when determining the sustainable stocking rate for an area. To reduce the risk of bush encroachment in grazing systems with focal points such as paddocks or watering points, stocking rates need to be lower than in systems with a more uniform grazing distribution. [source]

Spider family composition and species richness patterns in two savannah habitats along the eastern coastal plain of Africa

AFRICAN JOURNAL OF ECOLOGY, Issue 2 2010
Charles R. Haddad
Abstract The spider faunas of two savannah reserves along the eastern coastal plain of Africa are compared. Species richness was higher in the tropical area, with 493 species (54 families) from Mkomazi Game Reserve, Tanzania. Species richness was also high in the subtropics, with a total of 431 species (46 families) recorded from Ndumo Game Reserve, South Africa. Spider community structure was remarkably similar in the two reserves, with Salticidae, Gnaphosidae, Thomisidae, Theridiidae and Araneidae the most species-rich families in both reserves. Eleven of the fourteen most species rich families were the same. A similar proportion of families were represented by singleton and doubleton species. A genus- and species-level comparison of ten spider families indicates that while there is considerable overlap in the generic composition of the reserves (Sorensen's Quotient of similarity: all >0.650 except Linyphiidae, 0.166; Corinnidae, 0.500) there is little overlap between the species occurring in the two sites (0.000,0.571), which was particularly evident in the more species-rich families. A comparison of diversity of 57 families in each reserve with the spider biodiversity in the two sub-regions suggests that local biodiversity is largely determined by regional biogeographical influences rather than local ecological factors. Résumé On compare ici les araignées de deux réserves de savane situées le long de la plaine côtière de l'est de l'Afrique. La richesse en espèces était plus grande dans la région tropicale, avec 493 espèces (54 familles) dénombrées dans la Mkomazi Game Reserve, en Tanzanie. La richesse en espèces était aussi élevée dans la région subtropicale, avec un total de 431 espèces (46 familles) rapportées dans la Ndumo Game Reserve, en Afrique du Sud. La structure de la communauté des araignées était remarquablement semblable dans les deux réserves, et les Salticidae, Gnaphosidae, Thomisidae, Theridiidae et les Araneidae étaient aux deux endroits les familles les plus riches en espèces. Onze des quatorze familles les plus riches en espèces étaient les mêmes. Une proportion semblable de familles n'étaient représentées que par des espèces singletons ou doubletons. Une comparaison de dix familles d'araignées au niveau du genre ou de l'espèce indique que, s'il existe un important chevauchement de la composition générique des deux réserves (quotient de similitude de Sorensen : tous > 0,650 à l'exception des Linyphiidae, 0,166, et des Corinnidae, 0,500), il y a peu de chevauchement entre les espèces qui vivent dans les deux sites (0,000,0,571), ce qui était particulièrement évident dans les familles les plus riches en espèces. Une comparaison de la diversité de 57 familles dans chaque réserve avec la biodiversité des araignées des deux sous-régions suggère que la biodiversité locale était largement déterminée par des influences biogéographiques régionales plutôt que par des facteurs écologiques locaux. [source]

Differences in woody vegetation are unrelated to use by African elephants (Loxodonta africana) in Mkhuze Game Reserve, South Africa

AFRICAN JOURNAL OF ECOLOGY, Issue 1 2010
Angela M. White
Abstract The reintroduction of African elephants into fenced game reserves throughout South Africa has presented managers with several challenges. Although elephants are a natural part of southern African ecosystems, their confinement to fenced protected areas in South Africa has exacerbated their potential to impact their habitats negatively. However, many studies investigating the impact of elephants have failed to control for the effects of other browsers on the vegetative community. In this study, we used location data on an elephant herd to delineate high-use and low-use areas. This paired design allowed us to minimize confounding factors that could explain differences in the structure, diversity and utilization of woody species. We found little evidence to suggest elephant-mediated change in, or selection for, the structure or diversity of woody species; however, our results suggest that elephants may be altering the composition of species by preferentially using areas with higher canopy diversity and by enhancing sapling recruitment. Although stripping of bark was higher in high-use areas, there was no evidence of differential mortality of tree species. Therefore, in our study area, and over the current time scale, elephants are having a negligible impact on the vegetative community. Résumé La réintroduction d'éléphants africains dans des réserves de faune clôturées dans toute l'Afrique du Sud représente plusieurs défis pour les gestionnaires. Bien que les éléphants fassent naturellement partie des écosystèmes d'Afrique australe, leur confinement dans des aires protégées clôturées en Afrique du Sud a exacerbé leur capacité d'avoir des impacts négatifs sur leurs habitats. Pourtant, les nombreuses études qui ont recherché l'impact des éléphants ont omis de contrôler l'effet des autres herbivores sur la communauté végétale. Dans cette étude, nous avons utilisé des données sur la localisation des hardes d'éléphants pour délimiter les zones plus ou moins fréquentées. Cette étude couplée nous a permis de minimiser les facteurs prêtant à confusion qui pouvaient expliquer des différences de structure, de diversité et d'utilisation des espèces ligneuses. Nous avons trouvé peu de preuves qui auraient indiqué que les éléphants changeaient ou sélectionnaient la structure ou la diversité des espèces ligneuses; cependant, nos résultats suggèrent que les éléphants pourraient modifier la composition des espèces en choisissant de préférence les zones où la diversité de la canopée est plus élevée et en stimulant le recrutement de jeunes plants. Même si les arrachages d'écorces étaient plus nombreux dans les zones très fréquentées, il n'y avait aucune preuve d'une mortalité différentielle selon les espèces d'arbres. C'est pourquoi, dans l'aire où nous avons travaillé, et pour le moment, on peut dire que les éléphants n'ont qu'un impact négligeable sur la communauté végétale. [source]

An assessment of the puku (Kobus vardonii Livingstone 1857) population at Lake Rukwa, Tanzania

AFRICAN JOURNAL OF ECOLOGY, Issue 4 2009
Matthias Waltert
Abstract The population of puku, Kobus vardonii, at Lake Rukwa, one of only two in Tanzania, is poorly known. A multi-species dry season game count carried out in Rukwa Game Reserve (RGR) in 2004 estimated a population size of 1729, but was associated with a high margin of error [coefficient of variation (CV) 0.88]. To increase the precision for the local puku population estimate, we conducted a zig-zag line transect survey restricted only to areas occupied by puku in the dry season of 2006. This survey technique produced an estimate of 776 individuals and the CV was considerably reduced to 0.29. Puku herd size was comparable with the studies carried out in the Kilombero valley, Tanzania and in Kasanka National Park, Zambia, thus broadly confirming the herding ecology of this species. We found that pukus were restricted to the central parts of the floodplains, suggesting an avoidance of habitats used by pastoralists at the edge of RGR. Compared with the estimates of the puku population made in the 1980s, the puku population has declined. We recommend regular monitoring and enforcement of the current management plan to conserve the local puku population. Résumé Le statut de la population du puku Kobus vardonii au lac Rukwa, une des deux seules populations de Tanzanie, est mal connu. Un dénombrement de nombreuses espèces animales réalisé en saison sèche dans la Réserve de Faune de Rukwa (RGR) en 2004 a estimé la taille de la population à 1 729, mais ce chiffre était associéà une grande marge d'erreur (CV 0,88). Pour améliorer la précision de l'estimation de la population de pukus, nous avons mené une étude par transect en zigzag limitée aux zones occupées par les pukus, pendant la saison sèche de 2006. Cette technique d'étude a donné une estimation de 776 individus, et la CV était considérablement réduite, à 0,29. La taille des hardes de pukus était comparable à celle relevée dans la vallée de Kilombero, en Tanzanie, et dans le Parc National de Kasanka, en Zambie, confirmant ainsi l'écologie en harde de cette espèce. Nous avons découvert que les pukus se limitaient aux parties centrales des plaines inondables, ce qui suggère qu'ils évitent les habitats fréquentés par les pasteurs à la limite de la Réserve de Faune de Rukwa. Comparée aux estimations de cette population de pukus réalisées dans les années 1980, cette population a décliné. Nous avons recommandé d'assurer un suivi régulier et d'appliquer le plan de gestion actuel pour conserver la population locale de pukus. [source]

Elephants caught in the middle: impacts of war, fences and people on elephant distribution and abundance in the Caprivi Strip, Namibia

AFRICAN JOURNAL OF ECOLOGY, Issue 2 2009
Michael J. Chase
Abstract We conducted wet [26 March,4 April 2003 (Apr03)] and dry [1,8 November 2005 (Nov05)] season aerial surveys of African elephants (Loxodonta africana Blumenbach) in the Caprivi Strip, Namibia to provide an updated status report on elephant numbers and distribution and assist with a historical analysis of elephant distribution and abundance in the Caprivi Strip. During the wet season when water was available in seasonal pans, elephants were widely distributed throughout the survey area. In contrast, during the dry season, a majority of elephant herds occurred within 30 km of the perennial Kwando, Linyanti and Okavango rivers and few herds occurred within the West Caprivi Game Reserve where water in the seasonal pans was limited. We estimated 5318 elephants for the 7731-km2 survey area (0.71 elephants km,2) for the Apr03 wet season survey and 6474 elephants for the 8597-km2 survey area (0.75 elephants km,2) for the Nov05 dry season survey. Based on our aerial surveys and reports of elephant numbers and distribution from historical aerial surveys and telemetry studies, civil war, veterinary fences and human activities appear to have effected changes in African elephant abundance, distribution and movements in the Caprivi Strip, Namibia since 1988 when the first comprehensive aerial surveys were conducted. Résumé En saison des pluies (avril 2003) et en saison sèche (novembre 2005), nous avons réalisé des contrôles aériens des éléphants africains (Loxodonta africana Blumenbach) dans la Bande de Caprivi, en Namibie, pour pouvoir fournir un rapport actualisé sur le statut du nombre et de la distribution des éléphants, et aider une analyse de longue durée de la distribution et de l'abondance des éléphants dans la Bande de Caprivi. Pendant la saison des pluies, lorsque l'eau était disponible dans les « pans » saisonniers, les éléphants étaient largement distribués dans toute la zone étudiée. Par contre, en saison sèche, la grande majorité des troupeaux d'éléphants se trouvaient dans les 30 km des rivières permanentes Kwando, Linyanti et Okavango, et peu de troupeaux se trouvaient dans la West Caprivi Game Reserve, où l'eau était limitée dans les pans saisonniers. Nous avons estimé le nombre d'éléphants à 5 318 dans les 7 731 km² de la zone étudiée (0,71 éléphant km,²) pour l'étude faite en saison des pluies d'avril 2003, et à 6 474 éléphants dans les 8 597 km²étudiés (0,75 éléphant km,²) pendant la saison sèche de novembre 2005. En se basant sur nos contrôles aériens et sur des rapports concernant le nombre et la distribution des éléphants provenant de contrôles aériens et d'études télémétriques anciens, il s'avère que la guerre civile, les barrières vétérinaires et les activités humaines ont provoqué des changements de l'abondance, de la distribution et des déplacements des éléphants dans la Bande de Caprivi depuis 1988, date où les premiers contrôles aériens complets ont été effectués. [source]

Trade-off between resource seasonality and predation risk explains reproductive chronology in impala

JOURNAL OF ZOOLOGY, Issue 3 2007
S. R. Moe
Abstract We investigated the variation in birth synchrony displayed by impala Aepyceros melampus populations across their distribution from southern to eastern Africa. Our analysis was based on field data from Chobe National Park in Botswana and Mala Mala Private Game Reserve in South Africa (4 and 13 years of monitoring, respectively). We compared our results with those from other studies conducted across the impala species range. Impala lambing was highly synchronized in Chobe with 90% of lambs born within 2 weeks in mid-November. Variation in rainfall in the preceding wet season explained 74% of variation in the dates of the first lamb observation in Mala Mala. In Chobe, the earliest birth peak occurred after the highest rainfall and the body condition of lambs in that cohort was also best for both males and females. No association was found between the lunar cycle and the estimated onset of the conception period, despite previous studies having found an association between the lunar cycle and the rutting behaviour in males. On a regional scale, impalas in areas with a marked dry season (several months with no rain) tend to synchronize births with the onset of the rains, when grass quality is highest. Number of months with rain explained 78% of the regional variation in birth synchrony. Neither latitude nor total rainfall contributed significantly to a stepwise multiple regression model. These data support the theory that impalas synchronize births in areas with a highly seasonal food supply, and temporally space births in less seasonal (equatorial) areas to reduce predation risks. [source]

Proceedings of the Conference on Photo-responsive Materials

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 9 2004
Andrew Leitch
The Conference on Photo-responsive Materials took place 25,29 February 2004 at Kariega Game Reserve, South Africa. It was focused primarily on III-nitrides (GaN, AlGaN, InGaN), SiC, ZnO and other wide gap materials, chalcopyrites such as CuInSe2 for photovoltaic applications, and novel photoresponsive materials including polymers. Material-related issues within the scope of the conference were crystal growth and epitaxy, characterisation (photoluminescence, DLTS, IR spectroscopy), defect-related studies, processing, and opto-electronic devices (modelling and novel structures). [source]

Preface: phys. stat. sol. (c) 1/9

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 9 2004
Andrew Leitch
The Conference on Photo-responsive Materials took place at the Kariega Game Reserve in the Eastern Cape, South Africa from 25,29 February 2004. More than 60 delegates from 12 different countries participated in the four-day event. The purpose of the conference was to bring together scientists working on various aspects of photo-responsive materials, so as to stimulate this important field of solid state physics in Southern Africa. As may be seen from the list of papers appearing in these proceedings, there was much interest in copper indium diselenide as a thin film material for photovoltaic applications. Also worth mentioning were the valuable contributions on ZnO, GaN and other materials that are currently attracting attention worldwide. The conference program allowed sufficient time for interaction and exchanging of views. Being in a game reserve in the heart of the beautiful Eastern Cape, delegates were also taken on game drives and had the opportunity of taking a river cruise up the Kariega River to view the majestic fish eagle. The members of the academic program committee were: Vivian Alberts (Rand Afrikaans University), Danie Auret (University of Pretoria), Darrell Comins (University of the Witwatersrand), and Reinhardt Botha and Andrew Leitch (University of Port Elizabeth). All papers appearing in these proceedings underwent a strict reviewing process separate from the conference. We express our appreciation to the referees for their diligence in this important task. The conference was organized by the Department of Physics at the University of Port Elizabeth, under the auspices of the Condensed Matter Physics and Materials Science (CMPMS) subgroup of the South African Institute of Physics. It was sponsored by EMF Limited (UK), Sensors Unlimited Inc. (USA), and Carl Zeiss (Pty) Ltd. Special thanks must go to Dr Eunete van Wyk for her professional assistance in the preparation of these proceedings. [source]

Inbreeding and density-dependent population growth in a small, isolated lion population

ANIMAL CONSERVATION, Issue 4 2010
M. Trinkel
Abstract In South Africa, more than 30 small, enclosed game reserves have reintroduced lions over the last two decades, which now house more than 500 individuals. There is a high risk of inbreeding in these fragmented, fenced and isolated populations, which may be compounded by a lack of management guidelines. A population of 11 founder lions Panthera leo was reintroduced to Madikwe Game Reserve in 1995, and this population has in turn become a source for reestablishing other populations. Only four lineages were reintroduced, founder males were related to founder females, and since 1997, only one male lineage maintained tenure for >9 years, resulting in breeding with direct relatives. Interventionist management to limit lion population growth and inbreeding in Madikwe has taken the form of translocating, trophy hunting and culling of mainly sub adult lions. Despite this management, inbreeding started 5 years after reintroduction. Reproductive performance and thus population growth in Madikwe were dependent on the overall lion population density. When lion density was low, females first gave birth at a significantly younger age and produced larger litters, resulting in a high population growth rate, which decreased significantly when lion density in the park reached carrying capacity, that is, 61 lions. This might have profound consequences for future reestablishment of lion populations when restocking new reserves: our study illustrates the need for founder populations of reintroduced endangered predator species to be as large and genetically diverse as possible, and thereafter new genetic material should be supplemented. The development of such management guidelines is becoming very important as large predator populations become increasingly fragmented and managed as metapopulations. [source]

Front and Back Covers, Volume 23, Number 5.

ANTHROPOLOGY TODAY, Issue 5 2007
Ocotober 200
Front and back covers caption, volume 23 issue 5 Front cover The front cover illustrates Julie J. Taylor's article on the outcome of the San people's court case against the Botswana government. The photo shows Roy Sesana, leader of the San organization First People of the Kalahari and chief appellant in the case, with Gordon Bennett, the San group's lawyer, at the start of the case in July 2004. In the course of the last century, the San or Bushmen of southern Africa became possibly the most studied indigenous group in the world. In addition to suffering land dispossession and violence during the colonial period, their image in the West has long been that of exotic and innocent ,Other', fuelled over time by the work of scientists, anthropologists and filmmakers among others. In recent years the San have become part of wider debates about indigeneity, poverty and development, often in relation to land rights. Many San have formed their own representative institutions and have also entered into relationships with national and international NGOs to campaign for their rights as an indigenous minority. From 2004, San claims to land in the Central Kalahari Game Reserve in Botswana drew unprecedented attention in the international media, due in part to the efforts of local NGOs and the British-based advocacy group Survival International. After protracted court proceedings and much controversy, the case finally came to an end in late 2006. At first sight the outcome appeared to offer victory to San applicants, but matters in the Central Kalahari are far from resolved, raising questions about the role of advocacy groups and the fate of marginalized San groups elsewhere. Back cover (IM)PERSONAL MONEY Roboti of Giribwa Village, Trobriand Islands (above) is seen wearing the armshell Nanoula and the necklace Kasanai. Both have been circulating in the kula for at least a century and were already famous when Malinowski saw them. He was sure that these valuables were not money because they were not an impersonal medium of exchange, but Marcel Mauss, in a long footnote to The gift, wrote: ,On this reasoning there has only been money when precious things have been really made into currency , namely have been inscribed and impersonalised, and detached from any relationship with any legal entity, whether collective or individual, other than the state that mints them, One only defines in this way a second type of money , our own.' This exchange was in some ways the high point of economic anthropology. The world of national currencies issued and controlled by states and banks must now come to terms with innumerable virtual instruments such as those seen flashing on the screens of the Chicago Mercantile Exchange (below). But, as the current ,sub-prime mortgage' crisis shows, these anonymous money instruments are still closely linked to personal credit. The challenge facing anthropologists today is to renew the legacy of Mauss and Malinowski in ways that illuminate such matters of universal practical concern. In this issue, Keith Hart argues that money, like society itself, is and always has been both personal and impersonal. A pragmatic anthropology should aim to show that the numbers on people's financial statements constitute a way of summarizing their relations with society at a given time. The next step is to explain how these numbers might serve in building a viable personal economy. When we are able to take responsibility for our own economic actions, we will understand better the social forces impinging on our lives. Then it will become more obvious how and why ruling institutions need to be reformed for all our sakes. [source]

Habitat availability, hunting or poaching: what affects distribution and density of large mammals in western Tanzanian woodlands?

AFRICAN JOURNAL OF ECOLOGY, Issue 4 2009
Matthias Waltert
Abstract Game reserves (GR) in Tanzania have been found to support similar or lower densities of large mammals compared with National parks (NP). But as these areas usually differ considerably not only in regard to management but also to environmental factors, we assessed the relative importance of vegetation cover, species-specific habitat preferences and legal (trophy hunting) and illegal off-take for observed differences in species-specific densities. In the Katavi ecosystem, open habitats were characteristic elements of Katavi NP, while Rukwa GR was dominated by miombo forest. In an inter-specific comparison, density differences were moderately correlated with preferences for open habitats, and with estimates of combined legal and illegal off-take but not with one of these separately. In a multiple linear regression, open habitat preference was found to explain 39.6% of the density differences between the two protected areas. This analysis suggests that the broad-scale pattern of most species' distributions is governed by differing vegetation cover but that several species are overexploited by illegal (elephant, giraffe, buffalo, bush pig, warthog) or combined off-take (hippopotamus, eland, waterbuck), thus emphasizing the need for quota readjustments and a more efficient anti-poaching control. Résumé En Tanzanie, on a découvert que les réserves de chasse, comparées aux parcs nationaux, abritaient des densités semblables ou inférieures de grands mammifères. Mais étant donné que ces zones diffèrent d'habitude considérablement, en termes non seulement de gestion mais aussi de facteurs environnementaux, nous avons évalué l'importance relative de la couverture végétale, des préférences spécifiques des espèces en matière d'habitat, et des prélèvements légaux (chasse aux trophées) et illégaux dans les différences constatées des densités spécifiques. Dans l'écosystème de Katavi, les habitats ouverts sont des éléments caractéristiques du Parc National de Katavi (PN) alors que la Réserve de Chasse de Rukwa (RC) est dominée par la forêt à miombo. Dans une comparaison interspécifique, les différences de densitéétaient modérément liées à la préférence pour des habitats ouverts et aux estimations de prélèvements légaux et illégaux combinés, mais pas avec les estimations séparées des uns ou des autres. Dans une régression linéaire multiple, on a découvert que la préférence pour un habitat ouvert expliquait 39.6% des différences de densité entre les deux aires protégées. Cette analyse suggère que le schéma, à grande échelle, de la distribution de la plupart des espèces est régi par une différence de couverture végétale, mais que plusieurs espèces semblent être surexploitées par les prélèvements illégaux (éléphants, girafes, buffles, potamochères, phacochères) ou combinés (hippopotames, élands, waterbucks), ce qui souligne la nécessité de réajuster les quotas et d'exercer des contrôles anti-braconnage plus efficaces. [source]

The impact of cattle ranching on large-scale vegetation patterns in a coastal savanna in Tanzania

Is use of translocation for the conservation of subpopulations of oribi Ourebia ourebi (Zimmermann) effective?

AFRICAN JOURNAL OF ECOLOGY, Issue 3 2009
A case study
Abstract In South Africa, the oribi, Ourebia ourebi is an endangered small antelope that requires conservation management and intervention to prevent their extinction. Use of translocation for the conservation of subpopulations facing local extinction in the wild has been proposed. In this study, fifteen oribi from threatened populations were captured and released (November 2004) on a private game reserve in KwaZulu-Natal, South Africa. Radio telemetry was used to monitor the dispersal and survival of translocated oribi. Only one death occurred during that period. All other released oribi survived, and most remained in close proximity of the release site for more than a year postrelease. Reproduction also occurred. This suggests that, translocation could be a viable option for conserving wild populations of oribi, assuming that other factors, such as availability of suitable grassland habitat and that poaching has been curtailed, are met. Résumé En Afrique du Sud, l'oribi Ourebia ourebi est une petite antilope en danger qui requiert une gestion de la conservation et une intervention pour empêcher son extinction. On a proposé le recours à la translocation pour conserver les sous-populations confrontées à une extinction locale dans la nature. Dans le cadre de cette étude, 15 oribis de populations menacées ont été capturés pour être relâchés, en novembre 2004, dans une réserve de faune privée au KwaZulu-Natal, en Afrique du Sud. La radio-télémétrie a été utilisée pour suivre la dispersion et la survie des oribis déplacés. Il n'y eut qu'un mort pendant cette période. Tous les autres oribis relâchés ont survécu, et la plupart sont restés à proximité du site de lâcher pendant plus d'un an. Il y eut aussi des reproductions. Ceci suggère que la translocation peut être une option viable pour la préservation de populations sauvages d'oribis, pour autant que d'autres facteurs soient présents, comme la disponibilité d'habitats de prairies favorables, et que le braconnage soit sous contrôle. [source]

Preface: phys. stat. sol. (c) 1/9

Differences in woody vegetation are unrelated to use by African elephants (Loxodonta africana) in Mkhuze Game Reserve, South Africa

Home range size, spatial distribution and habitat use of elephants in two enclosed game reserves in the Eastern Cape Province, South Africa

AFRICAN JOURNAL OF ECOLOGY, Issue 2 2009
C. Roux
Abstract We studied space use and habitat selection by elephants in two enclosed reserves in the Eastern Cape Province (South Africa) that conserve components of the regionally important and poorly conserved Thicket Biome. Home ranges of bulls and herds occupied most of the reserves, and core areas were significantly smaller and centred on permanent water. There was no significant difference in home range size of bulls and herds and both were significantly smaller in winter than summer. Components of the Thicket Biome occurred in the home ranges and core areas of all elephants where it was either used according to its abundance or avoided. However, this should not be interpreted as indicating that elephants will not affect plants of the Thicket Biome since change will be cumulative and monitoring should be ongoing to ensure the conservation of this regionally important Biome. Résumé Nous avons étudié l'utilisation de l'espace et la sélection de l'habitat par les éléphants dans deux réserves clôturées de la Province du Cap Oriental, en Afrique du Sud, qui préservent les composantes d'un Biome important dans la région et cependant mal conservé, le biome de savane broussailleuse. Les domaines vitaux des mâles et des troupeaux occupaient la plus grande part des réserves, et leurs zones centrales étaient significativement plus petites et centrées sur les points d'eau permanents. Il n'y avait pas de différence significative de la taille des domaines vitaux des mâles et des troupeaux, domaines qui étaient significativement plus petits en hiver qu'en été. Des composantes du biome broussailleux étaient présentes dans le domaine vital et dans l'aire centrale de tous les éléphants, où elles étaient soit utilisées selon leur abondance, soit évitées. Cependant, il ne faudrait pas en déduire que cela indique que les éléphants n'affectent pas les plants du Biome à broussailles puisque les changements seront cumulatifs; il faut au contraire poursuivre le monitoring pour assurer la conservation de ce biome important au niveau régional. [source]

The impact of elephants on the marula tree Sclerocarya birrea

AFRICAN JOURNAL OF ECOLOGY, Issue 4 2002
Michelle E. Gadd
Abstract This study determined the abundance, density and population structure of the marula tree, Sclerocarya birrea, in three game reserves in South Africa, and assessed patterns and amounts of new and cumulative impact of elephants. Elephant feeding was very patchy so several attributes of individual trees, sampled transects and communities that might influence elephant herbivory were investigated. The incidence and type of elephant impact (bark, branch or stem breakage) were significantly related to tree diameter, but not to fruiting nor proximity to roads. At the transect level, elephant impact was influenced by density of marula trees, but was not influenced by proximity to roads, nor proportion of marula trees bearing fruits in the vicinity. At the community level, elephant impact was higher on reserves with higher total marula densities. Fourfold differences in elephant densities (0.08,0.30 elephants km,2) did not explain marula consumption: the percentage of trees with branch damage was similar across reserves and bark damage was inversely proportional to elephant density. Variation across reserves may reflect local and landscape-level marula tree abundance, differences in alternative food plants and individual feeding habits. The recorded levels of impact appeared to be sustainable because mortality rates were low, affected trees often recovered, and small trees were not preferentially preyed upon. Résumé Cette étude détermine l'abondance, la densité et la structure de la population de l'arbre à Marula, Sclerocarya birrea, dans trois réserves de faune sud-africaines et évalue le schéma et la totalité des impacts nouveaux et successifs des éléphants. Les éléphants se nourrissaient çà et là, de sorte que l'on a étudié divers attributs des arbres pris individuellement, des transects échantillons et des communautés, qui pouvaient influencer le caractère herbivore des éléphants. L'incidence et le type d'impact (écorces, branches ou jeunes pousses) étaient significativement liés au diamètre de l'arbre, mais non à la fructification, ni à la proximité des routes. Au niveau du transect, l'impact des éléphants était influencé par la densité des arbres à Marula, mais pas par la proximité des routes, ni par la proportion d'arbres à Marula en fruits dans le voisinage. Au niveau de la communauté, l'impact des éléphants était plus élevé dans les réserves qui comptaient la plus forte densité totale d'arbres à Marula. Une différence de 1 à 4 dans la densité des éléphants (0.08-0.30/km2) n'explique pas la consommation de marula : le pourcentage d'arbres présentant des branches endommagées était similaire dans toutes les réserves, et les dommages causés aux écorces étaient inversement proportionnels à la densité des éléphants. La variation observée entre les réserves pourrait refléter l'abondance des arbres à Marula tant locale que liée au paysage, des différences dans l'abondance de nourriture végétale alternative et les habitudes alimentaires individuelles. L'importance de l'impact relevé semblait être soutenable parce que le taux de mortalitéétait faible, que les arbres touchés récupéraient souvent et que les petits arbres n'avaient pas souvent la préférence des éléphants. [source]

Inbreeding and density-dependent population growth in a small, isolated lion population

Carnivore biodiversity in Tanzania: revealing the distribution patterns of secretive mammals using camera traps

ANIMAL CONSERVATION, Issue 2 2010
N. Pettorelli
Abstract Biodiversity monitoring is critical to assess the effectiveness of management activities and policy change, particularly in the light of accelerating impacts of environmental change, and for compiling national responses to international obligations and agreements. Monitoring methods able to identify species most likely to be affected by environmental change, and pinpoint those changes with the strongest impacts, will enable managers to target efforts towards vulnerable species and significant threats. Here we take a new approach to carnivore monitoring, combining camera-trap surveys with ecological niche factor analysis to assess distribution and patterns of habitat use of mammalian carnivore assemblages across northern Tanzania. We conducted 11 surveys over 430 camera-trap stations and 11 355 trap-days. We recorded 23 out of 35 carnivore species known to occur in Tanzania and report major extensions to the known distribution of the bushy-tailed mongoose Bdeogale crassicauda, previously thought to be rare. Carnivore biodiversity tended to be higher in national parks than in game reserves and forest reserves. We explored habitat use for seven species for which we had sufficient information. All species tended to be found near rivers and southern Acacia commiphora woodlands (except one mongoose species), and avoided deciduous shrubland, favouring deciduous woodland and/or open grassland. All species tended to avoid croplands suggesting that habitat conversion to agriculture could have serious implications for carnivore distribution. Our study provides a first example where camera-trap data are combined with niche analyses to reveal patterns in habitat use and spatial distribution of otherwise elusive and poorly known species and to inform reserve design and land-use planning. Our methodology represents a potentially powerful tool that can inform national and site-based wildlife managers and policy makers as well as international agreements on conservation. [source]

Grazing and landscape controls on nitrogen availability across 330 South African savanna sites

AUSTRAL ECOLOGY, Issue 7 2009
JOSEPH M. CRAINE
Abstract The availability of nitrogen (N) is an important determinant of ecosystem and community dynamics for grasslands and savannas, influencing factors such as biomass productivity, plant and herbivore composition, and losses of N to waters and the atmosphere. To better understand the controls over N availability at landscape to regional scales, we quantified a range of plant and soil characteristics at each of 330 sites in three regions of South Africa: Kruger National Park (KNP), private game reserves adjacent to KNP (private protected areas , PPAs) and Hluhluwe-iMfolozi Park (HiP). In comparing regions and sites within regions, grazing appeared to have a strong influence on N availability. Sites in the PPAs adjacent to KNP as well as sodic and alluvial sites in general typically had the highest N availability. The high N availability of these sites was not generally associated with greater potential N mineralization, but instead with less grass biomass and more forb biomass that indicated greater grazing pressure. Whereas sodic sites had a long history of high N availability as evidenced by their high soil ,15N, the greater N availability in the PPAs over the two parks appeared to be relatively recent. Grazer biomass, average potential mineralization rates and grass biomass for HiP were greater than KNP, yet there were no differences in N availability as indexed by soil and foliar ,15N between sites in the two parks. Although the short-term increase in N availability in PPAs is not necessarily deleterious, it is uncertain whether current productivity levels in those ecosystems is sustainable. With differences in management causing herbivore biomass to be 150% greater in the PPAs than the adjacent KNP, changes in plant communities and nitrogen cycling might lead to long-term degradation of these ecosystems, their ability to sustain herbivore populations, and also serve as an economic resource for the region. [source]