Effects of fire and fire intensity on the germination and establishment of Acacia karroo, Acacia nilotica, Acacia luederitzii and Dichrostachys cinerea in the field

BACKGROUND: While fire has been used in some instances to control the increase of woody plants, it has also been reported that fire may cause an increase in certain fire-tolerant Acacia tree species. This study investigated germination of Acacia karroo, A. luederitzii and Dichrostachys cinerea, thought to be increasing in density, as well as the historically successful encroaching woody species, A. nilotica, in savanna grassland, Hluhluwe-iMfolozi Park, South Africa. A. karroo is thought to be replacing A. nilotica as the dominant microphyllous species in the park. We tested the hypothesis that observed increases in certain woody plants in a savanna were related to seed germination and seedling establishment. Germination is compared among species for burnt and unburnt seeds on burnt and unburnt plots at three different locations for both hot and cool fires. RESULTS: Acacia karroo showed higher germination (A. karroo 5.1%, A. nilotica 1.5% and A. luederitzii 5.0%) levels and better establishment (A. karroo 4.9%, A. nilotica 0.4% and A. luederitzii 0.4%). Seeds of the shrub Dichrostachys cinerea did not germinate in the field after fire and it is thought that some other germination cue is needed. On average, burning of A. karroo, A. nilotica and A. luederitzii seeds did not affect germination. There was a significant difference in the germination of burnt seeds on burnt sites (4.5%) and burnt seeds on unburnt plots (2.5%). Similarly, unburnt seeds on unburnt sites germinated better (4.9%) than unburnt seeds on burnt sites (2.8%). CONCLUSION: We conclude that a combination of factors may be responsible for the success of A. karroo and that fires may not be hot enough or may occur at the wrong time of year to control A. karroo establishment in HiP. Although germination and establishment of A. karroo was higher than for A. nilotica a competitive advantage after fire could not be shown

Post-dispersal fate of Acacia seeds in an African savanna

African Acacia species are often major contributors to the progressive increase in the woody component of savannas, a phenomenon commonly referred to as bush encroachment. In Hluhluwe-iMfolozi Park, the numbers of adult Acacia nilotica (L.) Willd. Ex Del. subsp. kraussiana (Benth.) Brenan trees per hectare far exceed those of A. karroo Hayne adults. The relative dominance is reversed in the juvenile stage with A. karroo outnumbering A. nilotica threefold outside closed woodlands. We experimentally investigated the effects of location, structural habitat type, species, predator type and rodent presence on the level of post-dispersal seed predation in an attempt to explain species dominance in HluhluweiMfolozi Park. Post-dispersal predation of A. karroo seeds (21.8%) was higher than that of A. nilotica (12.7%). Predation levels depended on site, structural habitat type, level of protection from different predator types and rodent presence/absence. There was more rodent predation in tall grass areas (26.0%) than grazing lawn (10.7%) or canopy areas (15.2%), and most seeds (19.7%) were lost from unprotected control groups. Rodent presence was a significant factor in a model aiming to determine reasons for unexplained seed disappearance.Post-dispersal predation of seeds could not account for the differences in success between A. karroo and A. nilotica in Hluhluwe-iMfolozi Park

Occupant Protection during Orion Crew Exploration Vehicle Landings

The constellation program is evaluating current vehicle design capabilities for nominal water landings and contingency land landings of the Orion Crew Exploration vehicle. The Orion Landing Strategy tiger team was formed to lead the technical effort for which associated activities include the current vehicle design, susceptibility to roll control and tip over, reviewing methods for assessing occupant injury during ascent / aborts /landings, developing an alternate seat/attenuation design solution which improves occupant protection and operability, and testing the seat/attenuation system designs to ensure valid results. The EVA physiology, systems and Performance (EPSP) project is leading the effort under the authority of the Tiger Team Steering committee to develop, verify, validate and accredit biodynamics models using a variety of crash and injury databases including NASCAR, Indy Car and military aircraft. The validated biodynamics models will be used by the Constellation program to evaluate a variety of vehicle, seat and restraint designs in the context of multiple nominal and off-nominal landing scenarios. The models will be used in conjunction with Acceptable Injury Risk definitions to provide new occupant protection requirements for the Constellation Program

The Role of Social Behaviour in Carnivore Reintroductions

Reintroductions are becoming increasingly important in conservation management, particularly for large carnivores. Despite an increase in our understanding of carnivore social behaviour, wildlife managers often disregard this knowledge when reintroducing animals—largely owing to behavioural ecology and reintroduction biology rarely being unified in the literature or in graduate conservation management programmes. Here, we combine these two disciplines and outline the importance of considering aspects of social behaviour when reintroducing large carnivores. We identify two time periods of particular relevance: the time in temporary captivity before release and the period immediately after release. Prior to release, group composition of the animals to be released is important to promote social compatibility. After release, Allee effects arising from difficulty in finding suitable mates emerge as one of the most important constraints in some large-carnivore reintroduction programmes. In our view, incorporating considerations of social behaviour in conservation management would increase the efficiency and effectiveness of costly (carnivore) reintroduction programmes.CIB, University of Pretori

Home ranges of cheetahs (Acinonyx jubatus) outside protected areas in South Africa

As many carnivores occur outside protected areas, they are vulnerable to anthropogenic threats. In South Africa, the largest proportion of the distribution range of cheetahs (Acinonyx jubatus) is outside protected areas along the northern border of the country. Lions (Panthera leo) and spotted hyaenas (Crocuta crocuta) have been extirpated from these areas, leaving the depauperate carnivore guild dominated by cheetahs, leopards (Panthera pardus) and brown hyaenas (Hyaena brunnea). To determine how cheetahs use these areas, tracking collars were fitted to nine individuals from September 2003 to July 2009 in the Thabazimbi area, Limpopo, South Africa. Local Convex Hulls (αLoCoH) were used to determine home range sizes and 50 and 95 utilization distributions (UDs) were calculated. Male 95UDs ranged from 121.5 km2 to 607 km2 while females ranged from 14.7 km2 to 703.3 km2. Cheetahs utilized several ranches and mean home ranges sizes were larger than mean ranch size and larger than cheetah home ranges recorded in other southern African countries, with the exception of the more arid Namibia. This study provides valuable and relevant data on cheetahs and aids conservation practitioners in mitigating human-cheetah conflict on South African farmland.Columbus Zoo, Cat Life Foundation, Duemke Family Trust, Scovill Zoo, Carston Springs Trust and the DST-NRF Centre for Excellence for Invasion Biology.http://www.sawma.co.zaam201

Reintroduction of Top-Order Predators: Using Science to Restore One of the Drivers of Biodiversity

CIB, University of Pretori

The implications of the reclassification of South African wildlife species as farm animals

The Government Gazette No. 42464 dated 17 May 20191 amended Table 7 of the Animal Improvement Act (Act no. 62 of 1998), which lists breeds of animals, to include at least 32 new wild animal species, including 24 indigenous mammals. The list includes threatened and rare species such as cheetah, white and black rhinoceros, and suni. Some alien species such as lechwe, various deer species and rabbits are also included. The cornerstone of the original Act is ‘To provide for the breeding, identification and utilisation of genetically superior animals to improve the production and performance of animals in the interest of the Republic; and to provide for matters connected therewith.’ By declaring these wild animals as landrace breeds (in Table 7 of the regulations), the Act implies that they are locally developed breeds. The Act typically provides for landrace breeds to be bred and ‘genetically improved’ to obtain superior domesticated animals with enhanced production and performance. Similarly, provision is made for the Breeders Association to lay claim to the breed and to establish specific breed standards for animals to be included in stud books. Animals declared as landrace breeds can also be used for genetic manipulation, embryo harvesting, in-vitro fertilisation and embryo transfers. As indigenous species of wildlife are included in the recent amendment to the Act, the amendment is flawed

Composition of Near-Earth Asteroid 2008 EV5: Potential target for Robotic and Human Exploration

We observed potentially hazardous asteroid (PHA) 2008 EV5 in the visible (0.30-0.92 microns) and near-IR (0.75-2.5 microns) wavelengths to determine its surface composition. This asteroid is especially interesting because it is a potential target for two sample return mission proposals (Marco Polo-R and Hayabusa-2) and human exploration due to its low delta-v for rendezvous. The spectrum of 2008 EV5 is essentially featureless with exception of a weak 0.48-microns spin-forbidden Fe3+ absorption band. The spectrum also has an overall blue slope. The albedo of 2008 EV5 remains uncertain with a lower limit at 0.05 and a higher end at 0.20 based on thermal modeling. The Busch et al. (2011) albedo estimate of 0.12 is consistent with our thermal modeling results. The albedo and composition of 2008 EV5 are also consistent with a C-type taxonomic classification (Somers et al. 2008). The best spectral match is with CI carbonaceous chondrites similar to Orgueil, which also have a weak 0.48-microns feature and an overall blue slope. This 0.48-microns feature is also seen in the spectrum of magnetite. The albedo of CI chondrites is at the lower limit of our estimated range for the albedo of 2008 EV5.Comment: Pages: 19 Figures: 6 Tables: