Survey of elephant damage to baobabs in Tanzania's Lake Manyara National Park

This 1981 survey assesses elephant-induced bark damage and mortality in the population of baobab trees at Lake Manyara National Park. Comparisons are made with a similar survey conducted there in 1969. The age structure of the baobab population is estimated and linear and exponential survivorship curves are calculated. Damage and mortality increased over the 11 year interval but the basic form of the population age structure remained unchanged. Damage was found to increase while mortality decreased with tree size. Both damage and mortality are lower in the southern part of the park where the trees are less accessible to elephants. The recorded mortality was higher than expected values taken from the calculated survivorship curves but lower than mortalities in other parks where baobabs and elephants have been found together at high densities.     

Estimating forest elephant density in Sapo National Park (Liberia) with a rainfall model

The number of elephant dung‐piles lying on the forest floor is a function of the number of elephants present and the rainfall in the 2 preceding months. We present the results of a stochastic model that describes this relationship and we show how it can be used to estimate elephant numbers. The data from a survey in Sapo NP (Liberia) in 1989 are used as an example. The dung‐pile density was estimated at 152 km^?2 with confidence interval from 72 to 322, and the number of elephants was estimated to be 313 with confidence interval from 172 to 617.     

Ground dwelling mammal response to fire: A case study from Monga National Park after the 2019/2020 Clyde Mountain fire

Ground dwelling mammal communities are documented six months before and after the Clyde Mountain Wildfire of 2019/2020 in Monga National Park. Across eight sites before fire, approximately 12 ground dwelling mammal species were recorded. Survey effort post-fire increased to 40 sites, spanning three fire severity classes (low, moderate and extreme), revealed 16 ground dwelling mammal species. Species consist of small, medium and large native (one threatened species) and introduced mammals, though consistent with previous findings of ground dwelling mammal diversity in the area. Overall a greater number of species were found in low, compared to moderate and severe fire severity classes. Recovery and detection of mammals occurred in a shorter time period, again, in sites that experienced low, followed by moderate and extreme fire severity.     

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.     

Elk grazing and vegetation responses following a late season fire in Yellowstone National Park

We studied responses of aboveground production, grazing by elk and the availability of eight elements (Ca, Fe, K, Mg, N, Na, P, Zn) in a Yellowstone National Park sagebrush grassland following a fire in 1992. We compared four areas of differing fire history: (1) an area burned in 1992, (2) an area burned in 1992 and 1988, (3) an area burned in 1988 and (4) an area with no recent fire history. The year after burning, graminoids produced more aboveground biomass on burned areas compared with unburned areas. Forages growing on burned soils were highly concentrated with all nutrients, except Ca, when elk grazed the site. Despite nutrient-rich forage on burned areas, elk consumed little forage in these areas. We hypothesized that elk ate less than expected in burned areas because of a large bloom of lupine (Lupinus sericeus), which may be unpalatable to elk.     

The daily activity of the elephant in the Rwenzori National Park, Uganda

Eighteen elephants were followed individually in the Rwenzori National Park, Uganda for varying periods and their activity noted at 4-min intervals. Continuous data extending over 24 h or more were collected from seven of these elephants. About 75% of the total time was spent in feeding and about 75% of the feeding activity consisted of grazing or feeding at ground level. There were three feeding peaks, one in the morning, another in the afternoon and the third around midnight. The feeding rate tended to increase during the day. The proportion of the total feeding time spent in browsing increased in the dry season. Walking took place mainly at dusk. The principal sleeping period occurred during the small hours of the morning with a shorter rest period in the early afternoon. The elephants defaecated about eleven times in the 24 h and drank an average of 1–3 times. The rate of progress through the bush averaged 0–5 km/h. Comparisons are made with published data concerning the activity patterns of waterbuck and warthog in the Rwenzori Park and of elephants in the Tsavo National Park, Kenya.     

Successful artificial insemination of an Asian elephant at the National Zoological Park

For decades, attempts to breed elephants using artificial insemination (AI) have failed despite considerable efforts and the use of various approaches. However, recent advances in equipment technology and endocrine‐monitoring techniques have resulted in 12 elephants conceiving by AI within a 4‐year period (1998–2002). The successful AI technique employs a unique endoscope‐guided catheter and transrectal ultrasound to deliver semen into the anterior vagina or cervix, and uses the “double LH surge” (i.e., identifying the anovulatory LH (anLH) surge that predictably occurs 3 weeks before the ovulatory LH (ovLH) surge to time insemination. This study describes the 6‐year collaboration between the National Zoological Park (NZP) and the Institute for Zoo Biology and Wildlife Research (IZW), Berlin, Germany, that led to the refinement of this AI technique and subsequent production of an Asian elephant calf. The NZP female was the first elephant to be inseminated using the new AI approach, and was the fifth to conceive. A total of six AI trials were conducted beginning in 1995, and conception occurred in 2000. Semen was collected by manual rectal stimulation from several bulls in North America. Sperm quality among the bulls was variable and was thus a limiting factor for AI. For the successful AI, semen quality was good to excellent (75–90% motile sperm), and sperm was deposited into the anterior vagina on the day before and the day of the ovLH surge. Based on transrectal ultrasound, ovulation occurred the day after the ovLH surge. Pregnancy was monitored by serum and urinary progestagen, and serum prolactin analyses in samples collected weekly. Fetal development was assessed at 12, 20, and 28 weeks of gestation using transrectal ultrasound. Elevated testosterone measured in the maternal circulation after 36 weeks of gestation reliably predicted the calf was a male. Parturition was induced by administration of 40 IU oxytocin 3 days after serum progestagens dropped to undetectable baseline levels. We conclude that AI has potential as a supplement to natural breeding, and will be invaluable for improving the genetic management of elephants, provided that problems associated with inadequate numbers of trained personnel and semen donors are resolved. Zoo Biol 23:45–63, 2004. © 2004 Wiley‐Liss, Inc.     

Growth response of woody species to elephant foraging in Mwea National Reserve,Kenya

The African elephant (Loxodonta africana) is known to greatly affect the structure and dynamics of vegetation. In Mwea National Reserve, elephants foraged mainly on Acacia ataxacantha and Grewia bicolor out of the five most preferred woody species. However, out of the five preferred woody species, only Grewia virosa and G. bicolor showed a positive association between their fresh use and past elephant use. All the five selected woody species showed high coppicing response after foraging, with the highest coppice growth rates recorded for Acacia brevispica and lowest for Grewia tembensis. The mean heights of woody species utilized by elephants were highest for A. brevispica and lowest for G. bicolor. The mean heights of coppices emerging after utilization by elephants were not significantly different for A. ataxacantha but were significantly shorter in the rest of the foraged species. Elephants avoided the coppices of many other woody species notably C. africana, A. tortilis, A. mellifera, Combretum aculeatum among others in the reserve. The objective of this study was to understand the capacity of woody species to recover after utilization by elephants and feeding response of elephants to new woody species re‐growth; a cycle that would define the dynamics of food resources and elephant population within the reserve.