Conservation and behavior of Africa＇s ＂Big Five＂

We examine the conservation status of Africa＇s ＂Big Five＂： lion, leopard, buffalo, black and white rhinoceros and elephant, and the role of behavioral knowledge in their conservation. Efforts to conserve these flagship species consist of in situ conservation, captive breeding and reintroductions. With a few exceptions, we find limited evidence that knowledge of behavior informs conservation programs targeted at these species. For management in the wild, knowledge of infanticide and ranging can provide guidelines for realistic hunting quotas and corridors between protected areas, respectively. For ex situ and reintroduction programs, behavioral knowledge is chiefly focused on improved animal husbandry. Despite a formidable understanding of these species＇ behavior, the practicalities of using such knowledge may be diminished because exploitation of these species is so forceful and the bulk of efforts aimed at conserving these species （and indeed most other African species） are primarily in situ where behaviorally driven interventions are limited. Our comparative findings suggest that behavior has been of rather narrow use in the conservation of these flagship species [Current Zoology 60 （4）： 486--499, 2014].     

The impact of giraffe, rhino and elephant on the habitat of a black rhino sanctuary in Kenya

The habitat in an enclosed black rhino sanctuary, the Sweetwaters Game Reserve in Kenya, is being altered as populations of elephant, giraffe and black rhino increase. Height‐specific browse impact data were recorded for 1075 trees of the dominant species, the whistling thorn, Acacia drepanolobium. Rhinos and elephants browsed 18% of these trees in 1 year, including 5% that were killed or removed. The remaining trees were subjected to high levels of giraffe browse and low rainfall and grew by only 7.5 cm in a year. A mathematical model has been constructed that predicts how the number of trees ha^?1 will change with time under different browsing impacts. The model compares recruitment rate with removal rate and estimates that the number of trees ha^?1 will fall by 2% per year under the current browsing impact of black rhino (0.27 per km²), elephant (1.1 per km²) and giraffe (1.9 per km²). In 7 years, if the rhino and elephant populations continue to increase at the current rates, tree density will be falling by 5% per year and nearly one‐third of the trees will have been removed. These conditions are unsustainable and will result in habitat change and may affect rhino breeding. Several ways of alleviating the problem are discussed.     

犀牛在中国灭绝与人口压力关系的初步分析

三千多年以前,犀牛沿黄河两岸自西向东约有１８００多公里的广阔的分布北界。近三千年来,犀牛在中国的分布北界不断南移,它是我国犀牛地减性灭绝的重要特征。北界南移速度相当惊人,平均每年以０．５ｋｍ的速度禹南消退。犀牛在中国灭绝的根本原因是人口压力、中国古代人口对犀牛的压力包括直接与间接两个方面,通过简单计算可知,犀牛种群承受人口压力阈值小于４人／ｋｍ＾２。     

Feasibility of characterizing reproductive events in large nondomestic species by transrectal ultrasonic imaging

The feasibility of using transrectal ultrasonography for imaging the in situ morphology of the reproductive tract of females of several large nondomestic and endangered species was studied. Two black (Diceros bicornis) and 1 white (Diceros simus) rhinoceros, 2 Asian (Elaphus maximus) and 2 African (Loxodonta africana) elephants, 4 banteng (Bos javanicus), 1 gaur (Bos taurus), 1 giraffe (Giraffa camelopardalis), and 1 bactrian camel (Camelus bactrianus) were examined. Real-time ultrasonic images were obtained for the following structures: 1) rhinoceros—corpus luteum, ovarian follicles, uterus, cervix, and early conceptus, 2) elephants—posterior uterus and cervix, 3) banteng and gaur—corpus luteum, ovarian follicles, uterus, cervix, and conceptus, 4) giraffe—posterior uterus, placentomes, and late conceptus, 5) camel—posterior uterus, fetal fluids, and fetal membranes. Individual ovarian follicles were identified and monitored over a 34 day observational period in 1 nontranquilized white rhinoceros. Difficulties and limitations in viewing the ovaries in the elephants were attributed to operator inexperience and to the size, positioning, and demeanor of the animals. Pregnancy was detected in 1 black rhinoceros (27 days), 1 banteng cow (48 days), the giraffe (13 months), and in the bactrian camel (approximately 3½ months). Impending embryonic loss was suspected in the banteng cow because a heartbeat was not detected in the embryo proper; the cow was subsequently diagnosed nonpregnant by transrectal palpation 20 days later. It is concluded that the ability afforded by transrectal ultrasonography to detect and measure ovarian structures and changes in morphology of the tubular genitalia and conceptus provides a research methodology for the elucidation of certain aspects of reproductive biology, and a clinical modality for reproductive management and assisted fertilization programs of large nondomestic species.     

Relevance of elephant herbivory as a threat to Important Plants in the Addo Elephant National Park, South Africa

Although elephants are recognized as keystone species, the mechanisms of their impacts on biodiversity and community structure are rarely identified. In the Addo Elephant National Park (AENP), South Africa, elephant Loxodonta africana herbivory is apparently responsible for a significant reduction in plant richness, especially among the regionally rare and endemic small succulent shrubs and geophytes (Important Plants). We used faecal analysis to investigate the utilization of Important Plants in elephant diet in the AENP. Ninety plant species were identified in the diet. Only 14 of the 77 ( c . 18%) Important Plants previously thought particularly vulnerable to elephant browsing occurred in the diet, while at least 6% of species for which there are data were avoided. This refutes the generally held belief that elephant herbivory is the major driver of decline among Important Plants, and emphasizes the likely contribution of other mechanisms (e.g. knock-on effects, trampling, zoochory, etc.) to this phenomenon. The accurate prediction of impacts caused by elephants in the AENP and elsewhere, therefore requires an understanding of these previously marginalized mechanisms. By demonstrating appropriate cause-and-effect relationships between elephants and ecosystem change, we will be able to move beyond assuming that all the observed changes are due to elephant herbivory.