Current Research

Current research investigates spatial dynamics of elephants and their interactions with vegetation and other large herbivores in southern Africa. African elephants are an excellent species with which to study spatial processes because they are wide-ranging, traveling hundreds of kilometers and often crossing international boundaries. Understanding elephant movement dynamics is critical for conservation. In addition, elephants are keystone species, exerting an impact far greater than their abundance, and play a major role in regulating their environment by altering vegetation structure and composition, depositing nutrients, and through direct interactions with other species. While these actions help maintain biodiversity, there are concerns that as elephant populations continue to increase, their impacts may begin to have negative effects on other organisms.

Three projects address elephant spatial dynamics and their resultant impacts on vegetation and large herbivores. Each uses tools allowing different but complementary questions to be addressed, investigating diverse spatial scales of elephant impacts.

1) Using telemetry to assess habitat selection by elephants across space and time

Phenology of vegetation, the timing of its greening and dying, is an important predictor of herbivore use in many seasonal systems in Africa. In collaboration with South African National Parks and Nelson Mandela Metropolitan University, we use GPS collar data from seven elephant herds in Addo Elephant National Park, South Africa to investigate how movement patterns are influenced by seasonal changes in vegetation quality. Addo is relatively small, fenced park containing a succulent thicket ecosystem with many rare and endemic plants. Because of the fences, elephants cannot move outside the park to reduce impacts, making it of utmost importance to understand space use by elephants in order to protect critical habitat. The information we develop will allow prioritization of management efforts to specific areas at specific times, enhancing the conservation of both elephants and rare plants.

2) Assessing habitat suitability models for herbivores in an elephant-impacted savanna

Species distribution models (SDMs) relate animal locations to environmental variables to predict habitat use. We are using these models to evaluate the influence of African elephants on habitat use by other large herbivores. This allows us to scale up from a focus on habitat use by individuals to use by an entire population. SDMs are currently being developed for the Chobe riverfront in Chobe National Park, Botswana. These models will allow assessment of elephant influence on distribution of other large herbivores, helping suggest effective management strategies to protect both elephants and the other species with which they share their habitat.

3) Using remote sensing to analyze elephant utilization of vegetation

Satellite remote sensing is used to detect modification of vegetation by elephants across broad regions in hopes of enabling international monitoring of elephant effects. The Moving Standard Deviation Index (MSDI) applies a standard deviation calculation to satellite remote sensing imagery to assess vegetation degradation. Used previously for assessing impacts of livestock on rangelands, we apply the MSDI to identify elephant modification of vegetation. Elephant utilization data from the Chobe riverfront is being related to MSDI values calculated on the red and near infrared bands of MODIS satellite imagery. Model show a significant negative relationship between elephant utilization and MSDI in both bands, though the explanatory power of this relationship is low. Remote assessments allowing monitoring of elephant impacts across Africa have important potential to inform management decisions and should continue to be developed. Future work will assess the utility of the MSDI in the succulent thicket ecosystems of Addo Elephant National Park. If this technique is effective, historic satellite imagery can be used to show how alteration of vegetation proceeds as elephant populations increase over time, revealing the influence of elephant density on observed impacts.

The 2008 Assessment of South African Elephant Management emphasized the urgent need to study the effects of elephants and elephant density on biodiversity, and especially to evaluate the mechanisms of elephant impacts, in order to promote effective conservation. There is a dire need to understand the impact of increasing densities of elephants on species diversity. This project is helping to provide this knowledge as we investigate spatial impacts of elephants on vegetation and large herbivores in two diverse ecosystems of southern Africa. A better understanding of the influence of elephants on other species will enable more effective management decisions in an area where biodiversity conservation is essential for economic growth and local livelihoods.

{ 2 comments… read them below or add one }

Kathryn March 7, 2012 at 8:49 pm

i think u should put how much they:weigh, height, how big their head is, how long their trunk is, how big their tusks are, how big their ears are how thick their skin is, how long their back is, and how big their feet are. thanks i go to school and i need this info.

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Hayli September 24, 2012 at 2:55 pm

I think elephants are awesome creatures/animals/mammals and i love this websites.

SEE YA LATER!

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