20 research outputs found
Spawning and non-breeding activity of adult giant bullfrogs (Pyxicephalus adspersus)
Populations of the giant bullfrog (Pyxicephalus adspersus) have been poorly monitored due to the unpredictable appearance of this species aboveground. To better understand the activity of P. adspersus we quantified spawning by a population during five summers, and the activity of twenty adult frogs radio-tracked at the same site ca. twice weekly during the first three summers. In addition we examined animal activity, and population spawning in relation to meteorological variables, day of season, and moonlight. During the six-month summer period, males and females, respectively, spent 10±7 and 3±2 days at water, and 22±5 and 13±5 nights active. Greater proportions of radio-tracked animals moved overland, and/or foraged at night, around full moon, after heavy rainfall, when cooler, and less windy conditions prevailed. More animals were found at water, or on land during the day, and population spawning was more likely, earlier in summer, following heavier rainfall. Spawning occurred most frequently, in descending order, during December, January, and November, and was triggered by 40±16 mm rain in 24h. Spawning events lasted 2±1 days, but were prolonged around full moon. Numbers of males at spawning events varied between 30 and 500 males, and were positively correlated with the previous day's rainfall. Annually 6±1 spawning events occurred, and numbers of annual spawning events were positively correlated with total summer rainfall. Results of this study show that single counts of spawning adults will often result in gross underestimates of population size, and therefore, long-term adult counts are necessary to detect real population trends. Due to the unpredictable activity of adults, however, it may be more practical to monitor, within certain areas, the number of aquatic sites where breeding occurs, for improved conservation management of P. adspersus.The study was funded through the Endangered Wildlife Trust by
Rand Merchant Bank, the Pretoria East branch of the South African Hunterâs and Game
Conservation Association, Arrow Bulk Marketing, Cellar Rats Wine Club, Bill Flynn and
Diaz Films.http://www.tandfonline.com/loi/ther2
Does sexual selection explain the courtship song of field crickets (Gryllus bimaculatus)?
This
study evaluates the factors that may potentially affect the courtship songs of Gryllus bimaculatus,
(including: wing morphology, male body size and the maleâs current nutritional condition)
and whether female crickets assess male courtship song.This paper was initially
delivered at the Annual
Congress of the Biological
Sciences Division of the
South African Academy for
Science and Art, ARC-Plant
Protection Research Institute,
Roodeplaat, Pretoria, South
Africa on 01 October 2010.http://www.satnt.ac.zaam2014ab201
Community visioning in a transfrontier conservation area in Southern Africa paves the way towards landscapes combining agricultural production and biodiversity conservation
This study employed participatory approaches to establish ways of engaging local
communities within a transfrontier conservation area, towards achieving the goals
of integrated agricultural production and biodiversity conservation at a landscape
level, known as ecoagriculture. We facilitated farmersâ meetings to create charts
of local environmental and livelihood concerns and of their vision of the future.
Water scarcity, bad road conditions, unemployment and low harvests emerged
among the most prevalent concerns. Through a visioning process, participants
arrived at a desired future that was largely inclined towards improved livelihoods,
with comparatively little attention on biodiversity enhancement. We conclude
that stakeholder-driven ecoagriculture could be a sustainable strategy to
simultaneously achieve the communityâs vision and the goals of transfrontier
conservation areas, provided biodiversity management strategies are linked to
infrastructure improvement and income generating activities. We recommend a
community visioning process as an effective approach to encourage collective
action and to support local ownership of development programmes.The International Foundation for Science (IFS), the National
Research Foundation (South Africa), CIRAD (France) and the University of Pretoria.http://www.tandfonline.com/toc/cjep2
Unique combinations of stakeholders in a transfrontier conservation area promote biodiversity-agriculture integration
The world seeks to balance biodiversity protection and food
production. Transfrontier conservation areas (TFCAs) provide
unique opportunities for strategies that combine agriculture with
biodiversity conservation at a landscape level, known as ecoagriculture.
We identified and consulted ecoagriculture stakeholders
in a smallholder farming community within a TFCA. Data were
obtained through key informant interviews and questionnaire surveys.
Eighty-eight percent of key informants indicated that planned
ecoagriculture was feasible in the area and 95% of interviewed
farmers positively considered to plan the integration of biodiversity
conservation and farming. Potential conflicts of interest were
revealed among stakeholders but to a large extent, stakeholder
roles and interests were complementary, creating an environment
conducive to effective coordinated ecoagriculture planning.The National Research Foundation (South Africa), CIRAD
(France), the International Foundation for Science (IFS), the French Institute of South Africa
(IFAS), and the University of Pretoria. Ezemvelo-KZN Wildlife and the Wildlands Conservation
Trust.http://www.tandfonline.com/toc/wjsa2
Conservation implications of the age/size distribution of giant bullfrogs (Pyxicephalus adspersus) at three pen-urban breeding sites
Nothing is known about the age of wild Giant Bullfrogs (Pyxicephalus adspersus); yet this information has important
conservation implications for this regionally threatened species. We quantified and compared the age, body size and body
condition of adult male and female P. adspersus caught during spawning events at peri-urban breeding sites in Diepsloot and
at Glen Austin and Bullfrog pans in Gauteng Province, South Africa. Age was estimated from lines of arrested growth (LAG)
counted in cross-sections of animal phalanges. Males and females from all three sites possessed 6±2 (max. 16) and 4±1 (max.
11) LAG, respectively, suggesting shorter female longevity. Individuals with <3 LAG were not encountered at the breeding
sites, implying that newly metamorphosed P. adspersus require at least three years to reach sexual maturity. There was
no significant difference in the LAG counts of same-sex animals between the three sites. However, mean male snout-vent
length, mass, and body condition was greatest at Glen Austin Pan, and lowest at Bullfrog Pan. The latter is possibly explained
by chemical contamination of Bullfrog Pan from an adjacent disused landfill. At Glen Austin Pan males and females sampled
in 2004-06 for this study were significantly shorter than those sampled at the same site in 1992-93 for a different study. Our
results suggest that male P. adspersus may live for 20 years or more in the wild, but at some peri-urban breeding sites adult
life expectancy is declining. Juvenile P. adspersus are most threatened by terrestrial habitat transformation because they
take â„3 years to mature, during which period they may move great distances from their natal site. Differences in the size and
condition of P. adspersus between the study sites suggests that the species requires site-specific management in addition to
conservation at larger spatial scales.Rand Merchant Bank, the Pretoria East branch
of the South African Hunterâs and Game Conservation
Association, and Arrow Bulk Marketing.http://www.thebhs.org/pubs_journal.htmlam2017Paraclinical SciencesZoology and Entomolog
Analysis of landscape performance assessment by key stakeholders in a transfrontier conservation area
Stakeholder engagement has become an important aspect of sustainable natural resources management. This study analysed a landscape performance assessment by local and âexternalâ stakeholders in a transfrontier conservation area in Southern Africa. The landscape was divided into three agro-ecological zones and focus group discussions were facilitated for stakeholders to evaluate the landscape based on four ecoagriculture dimensions (production, conservation, livelihoods and institutions). The conservation dimension showed the best performance and the overall score for the landscape was 2.97, implying a fairly good performance. Perceptions and ratings did not significantly differ by age, gender or stakeholder groups. We conclude that despite their low levels of formal education and training, communal farmers can assess the performance of local landscapes in a consistent way. This study provides information about the degree to which the landscape under focus conformed to the main ecoagriculture goals and can guide development planning and extension service provision.The International Foundation for Science, the National Research Foundation (South Africa), CIRAD (France) and the University of Pretoria.http://www.tandfonline.com/loi/clar202019-03-11hj2017Zoology and Entomolog
A review of community-based natural resource management
Please read abstract in article.http://www.aloki.huam2018Centre for Wildlife ManagementMammal Research Institut
Inadequate community engagement hamstrings sustainable wildlife resource management in Zambia
We propose improvements for addressing the inadequate sustainable use of wildlife resources in the communityâbased natural resource management (CBNRM) programme in game management areas (GMAs) using case study data from Mumbwa and Lupande GMAs in Zambia. Firstly, we assess the sustainability of wildlife resources in these GMAs using design principles for enduring common pool institutions. Secondly, we propose the steps required to address the lack of sustainability of wildlife resources in the CBNRM programme in the two GMAs by building on indicators suggested by Ostrom's principles. The resource use patterns in the two GMAs were assessed according to their socioâeconomic and institutional factors. Comparisons were made between the two GMAs in relation to Ostrom's design principles. Accordingly, the combination of socioâeconomic and institutional factors restrains the sustainable use of wildlife resources in the two GMAs. Unless the Zambian government provides local communities with meaningful decisionâmaking powers and benefits for the utilisation and management of wildlife, this resource is likely to disappear outside national parks.The STRECC Programme of Maastricht University in the Netherlands and the Association of African Universities in Ghana. Michael John Somers also thanks the National Research Fund (NRF) Incentive Fund.https://wileyonlinelibrary.com/journal/aje2020-07-27hj2019Centre for Wildlife ManagementMammal Research Institut
Are high elevation crag lizards sensitive to climate change?
Crag lizards are restricted to montane areas where biota are strongly exposed to the effects of climate change. We investigated the factors shaping the distribution of Drakensberg crag lizards (Pseudocordylus melanotus melanotus; Cordylidae) by quantifying their elevational ranges, availability of shelter and prey as well as the thermal environment at three elevations. We recorded expected body temperatures using copper models of the lizards at each elevation in the field and in the laboratory, estimating the duration for which lizards must shelter from high temperatures. This correlated strongly with field observations of lizard activity during winter, spring and summer. Our models predicted that at lower elevations, lizards would shelter for longer periods each day, resulting in a marked reduction in time available for essential activities such as feeding and breeding, possibly explaining why these animals do not occur at lower elevations. The distribution and survival of these animals therefore appear to be impacted by the degree to which daytime temperatures limit their activity. Modelling future climate change scenarios at the high elevation site indicates that crag lizards would be resilient against small to moderate warming reflected by RCP4.5 climate change predictions, but populations are unlikely to persist under conditions predicted in the RCP8.5 scenario. This study is important as, unlike broader-scope studies that cannot quantify climate change impacts on individual species, we combine detailed field data with laboratory measurements and modelling of a single species to assess the ecological constraints to which crag lizards are exposed.The University of Pretoria and the National Research Foundation.https://onlinelibrary.wiley.com/journal/14429993hj2022Geography, Geoinformatics and MeteorologyPhysicsZoology and Entomolog