Long‐term high densities of African elephants clear the understorey and promote a new stable savanna woodland community

2021 ◽  
Author(s):  
Nicolas Ferry ◽  
Stéphane Dray ◽  
Hervé Fritz ◽  
Audrey Ipavec ◽  
Benjamin J. Wigley ◽  
...  
Keyword(s):  
African Elephants ◽  
Savanna Woodland

scholarly journals Temporal variation in resource selection of African elephants follows long‐term variability in resource availability

2019 ◽  
Vol 89 (2) ◽  
pp. e01348 ◽  
Author(s):  
Miriam Tsalyuk ◽  
Werner Kilian ◽  
Björn Reineking ◽  
Wayne Marcus Getz
Keyword(s):  
Temporal Variation ◽  
Resource Availability ◽  
Resource Selection ◽  
African Elephants ◽  
Selection Of

scholarly journals Enduring consequences of early experiences: 40 year effects on survival and success among African elephants ( Loxodonta africana )

2013 ◽  
Vol 9 (2) ◽  
pp. 20130011 ◽  
Author(s):  
Phyllis C. Lee ◽  
Luc F. Bussière ◽  
C. Elizabeth Webber ◽  
Joyce H. Poole ◽  
Cynthia J. Moss
Keyword(s):  
Life Histories ◽  
Maternal Investment ◽  
Loxodonta Africana ◽  
Adult Size ◽  
African Elephants ◽  
Age At First Reproduction ◽  
Early Experiences ◽  
Plastic Responses ◽  
Over 40 Years

Growth from conception to reproductive onset in African elephants ( Loxodonta africana ) provides insights into phenotypic plasticity, individual adaptive plastic responses and facultative maternal investment. Using growth for 867 and life histories for 2652 elephants over 40 years, we demonstrate that maternal inexperience plus drought in early life result in reduced growth rates for sons and higher mortality for both sexes. Slow growth during early lactation was associated with smaller adult size, later age at first reproduction, reduced lifetime survival and consequently limited reproductive output. These enduring effects of trading slow early growth against immediate survival were apparent over the very long term; delayed downstream consequences were unexpected for a species with a maximum longevity of 70+ years and unpredictable environmental experiences.

scholarly journals Efficacy of beehive fences as barriers to African elephants: a case study in Tanzania

Oryx ◽  
2018 ◽  
Vol 53 (1) ◽  
pp. 92-99 ◽  
Author(s):  
Ciska P.J. Scheijen ◽  
Shane A. Richards ◽  
Josephine Smit ◽  
Trevor Jones ◽  
Katarzyna Nowak
Keyword(s):  
National Park ◽  
Initial Period ◽  
Mitigation Strategy ◽  
Protected Area Management ◽  
Crop Loss ◽  
African Elephants ◽  
Farming Community ◽  
Udzungwa Mountains

AbstractNon-lethal mitigation of crop use by elephants Loxodonta africana is an increasingly important part of protected area management across Africa and Asia. Recently, beehive fences have been suggested as a potential mitigation strategy. We tested the effectiveness of this method in a farming community adjacent to Udzungwa Mountains National Park in southern Tanzania. Over a 5.5-year period (2010–2016) a beehive fence was introduced and subsequently extended along the Park boundary. The probability that one or more farms experienced crop loss from elephants on a given day was reduced in the presence of the fence and was reduced further as the fence was extended. The number of hives occupied by bees along the fence was the best predictor of elephants’ visits to farms. Farms closest to the fence experienced a greater likelihood of damage, particularly during the initial period when the fence was shorter. The number of farms affected by elephants declined when the fence was extended. There was a higher probability of damage on farms that were closer to the Park boundary and further from a road. Our mixed results suggest that the shape, length and location of fences need to be carefully planned because changes in a farm's long-term susceptibility to elephant damage vary between individual farms; fences need to be long enough to be effective and ensure that decreasing crop loss frequency is not outweighed by an increasing number of farms damaged per visit.

Oestrous Behaviour and Female Choice in the African Elephant

Behaviour ◽  
1983 ◽  
Vol 86 (3-4) ◽  
pp. 167-195 ◽  
Author(s):  
Cynthia J. Moss
Keyword(s):  
Female Choice ◽  
National Park ◽  
Size Class ◽  
African Elephants ◽  
Age Classes ◽  
Short Term ◽  
Individual Level ◽  
Female Behaviour ◽  
The Individual

Abstract1. During the course of an eight year field study of African elephants in Amboseli National Park, Kenya, from September, 1972 to December, 1980, females were seen exhibiting oestrous behaviour on 154 occasions, during which 43 copulations were witnessed. 2. Five categories of oestrous behaviour are described: a) wariness, b) the oestrous walk, c) the chase, d) mounting, and e) consort behaviour. 3. The oestrous behaviour as described was found to be temporally associated with ovulation, as judged by conceptions, in 70.7% of 58 cases. 4. The duration of oestrous periods is estimated at 2-6 days. 5. On average Amboseli females conceived once every 5 years and for each of these conceptions the female may only have been in oestrus once. 6. Evidence from the Amboseli study suggests that some females may exercise choice in mating partners. For example, females were able to elude their pursuers in 69.4% of all chases (n = 134). Observation of female behaviour during oestrus suggested that some females preferred to mate with males in the largest size class, particularly those in musth. 7. Two possible short-term advantages to females exercising choice in mating partners are suggested: a) avoidance of harassment from other bulls; and b) Large males in musth may be more likely to impregnate a female. 8. A possible long-term advantage to mating with a Large, and therefore older, male could be his ability to pass on a trait for longevity. 9. Although females may be exercising choice among the size/age classes, male-male competition among the Large males may override female choice on the individual level.

Cattle Mustering Efficiency Using Helicopters in a Monsoonal Savanna Woodland.

1986 ◽  
Vol 8 (2) ◽  
pp. 91 ◽  
Author(s):  
TH McCosker ◽  
AR Eggington
Keyword(s):  
Bos Indicus ◽  
Animal Husbandry ◽  
First Year ◽  
High Grade ◽  
Tropical Savanna ◽  
Long Term Effects ◽  
Management Information ◽  
Savanna Woodland ◽  
Percentage Points

This survey examined the long term effects of regular helicopter use on cattle tractability and provided herd management information on mustering rate and efficiency in a tropical savanna woodland environment. Ten individual herds of high grade Bos indicus breeders were mustered from four to eleven times over a four year period as part of a supplementation experiment conducted on "Mount Bundey" station. Paddock size ranged from 744 to 2,224 ha. Mean annual mustering efficiency (proportion mustered) was 71% (64-85%), 92% (83-99%), 96% (92-100%) and 94% (78-98%) for bulls, calves, steers and breeders respectively. Paddocks were totally clean of all animal classes in 25% of musters. Helicopter mustering of breeders and steers in the last three years of the study was 12 percentage points more efficient than horse mustering (assisted by a spotter plane) in the first year. Mustering rate in April-May averaged 69 beasts/hour while the August/September round averaged 102 beastdhour. Mustering efficiency did not differ between April-May and August-September musters. Helicopter mustering did not adversely affect tractability of the cattle when carried out in conjuntion with horsemen. The data indicate that 100% clean musters could not be routinely achieved in this monsoonal woodland savanna. even under relativelv intensive conditions. This conflicts with current BTEC requirements and hinders animal husbandry practices.

Therapy and prevention for mental health: What if mental diseases are mostly not brain disorders?

2019 ◽  
Vol 42 ◽  
Author(s):  
John P. A. Ioannidis
Keyword(s):  
Mental Health ◽  
Mental Disease ◽  
Brain Disorders ◽  
Social Stressors ◽  
Labor Education ◽  
Mental Diseases ◽  
Long Term Follow Up ◽  
Political Decisions

AbstractNeurobiology-based interventions for mental diseases and searches for useful biomarkers of treatment response have largely failed. Clinical trials should assess interventions related to environmental and social stressors, with long-term follow-up; social rather than biological endpoints; personalized outcomes; and suitable cluster, adaptive, and n-of-1 designs. Labor, education, financial, and other social/political decisions should be evaluated for their impacts on mental disease.

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