1. Sian Green¹,², Zeke Davidson¹, C. Patrick Doncaster²
Patterns of use and movement in the Mount Kenya Elephant Corridor: is it an effective corridor or simply an extension of habitat?
Sian Green¹,², Zeke Davidson¹, C. Patrick Doncaster²
¹ Marwell Wildlife, Colden Common, Winchester, UK, ² School of Biological Sciences, University of Southampton, Southampton, UK.
Introduction
The African elephant Loxodonta africana is currently under pressure from habitat decline, habitat fragmentation, trophy hunting, poaching and retaliatory persecution. In Kenya elephant populations are increasing, but this may be hindered by fragmentation and human-wildlife conflict. To alleviate these issues conservation strategies now include maintenance and creation of new wildlife corridors¹ and, in accordance with this, the Mount Kenya Elephant Corridor (MKEC) was created, linking the Mount Kenya Reserve to the Ngare Ndare Forest; this corridor also enhances connectivity along a historic migration route between these areas and the larger Samburu-Laikipia population.
Initial assessments showed elephants were using the corridor, however, not all elephants traversed the entire length and many took longer than was necessary to make the journey² which implies something may be hindering movement.
Aims
The aims of this project are:
To determine how much of the corridor area is being utilised by elephants and which areas are more intensely use.
To determine whether use of the corridor is consistent with it being used as an extension of home range or as a travel route.
Fig.1 Adult bull and regular corridor user, identified by uneven tusks and ragged ear notch.
Materials and methods
Data Collection:
25 camera traps were set out in the MKEC between February and May 2016
Images were sorted to species or type of disturbance and split into events occurring 30 mins apart.
Elephant images were sorted according to time of day, gender and individual ID.
The point centred quarter method was used to estimate tree density and proportion of trees damaged by elephants
GIS was used to collect data on other environmental variables.
Data analysis:
Occupancy models were used to determine proportion of corridor used.
Detection rates were used to model influence of different variables.
Trapping rates of elephants were plotted against proportion of damaged trees.
Time taken to move between cameras in different parts of the corridor were analysed using one-way ANOVA.
Results
Summary of trapping events:
43, 400 photographs analysed
2,070 wildlife events from 22 mammal species.
1,379 disturbance events, from vehicles, livestock and other human activities.
Travel speeds:
Fig.5 Location of camera traps within the corridor showing percentage of active trapping days and nights in which elephants were detected.
Fig.3 Mean of averaged journey speeds and 95% confidence intervals for each section of the corridor showing difference in speed for families (F2,28 = 12.76, p < 0.001) and adult bulls (F2,21 = 3.47, p = 0.049).
Occupancy and intensity of site use:
Elephants were detected at all sites, showing they were using the entire corridor area.
The best model for diurnal use included the following as predictors of detectability:
Tree density (Z = -3.44, p <0.001)
Anthropogenic disturbance (Z = -5.07, p <0.001)
Corridor width (Z = -4.47, p <0.001)
Interaction between tree density and disturbance (Z = 3.53, p <0.001)
The best model for nocturnal use included:
Distance to road (Z = , p < 0.001)
Distance to river (Z = -5.71, P < 0.001)
Anthropogenic disturbance (Z = -0.67, p = 0.51)
Tree damage:
Fig.2 Pausing to feed while in the corridor
Fig.4 Positive relationship between square-root trapping rate and trees damaged (r-squared = 0.27, F 1,18 = 6.57, p = 0.02).
References
Litoroh, M., Omondi, P., Kock, R., Amin, R., Conservation and Management Strategy for the Elephant in Kenya.
Winmill, N., The Mount Kenya Elephant Corridor’s Utilisation by Elephants and Its Perceived Success. University of Southampton.
Ngene, S.M., Van Gils, H., Van Wieren, S.E., Rasmussen, H., Skidmore, A.K., Prins, H.H.T., Toxopeus, A.G., Omondi, P., Douglas-Hamilton, I., The ranging patterns of elephants in Marsabit protected area, Kenya: The use of satellite-linked GPS collars. Afr. J. Ecol. 48, 386–400
Douglas-Hamilton, I., Krink, T., Vollrath, F., Movements and corridors of African elephants in relation to protected areas. Naturwissenschaften. 92, 158–163
Discussion
The effects of covariates could not always be adequately explained by detectability per se, in particular the negative effect of disturbance during the day, which was, instead, attributed to low rate of use due to avoidance of human activity. Preference for areas near roads and rivers at night may be due to traffic, and other disturbance, being less at this time.
Both genders moved through open grassland quickly, and at night, implying this part of the corridor is primarily used for transit.
Low speeds are associated with feeding⁵, so slow movement of families through the mixed vegetation, and the levels of tree damage found, supports the idea they were spending time foraging and are treating the corridor as an extension of habitat. Consistent high speeds of bulls indicates they were less interested in resources and were travelling through.
Elephants move at higher speeds, and at night through areas considered risky⁶. Behaviour in this study indicates part of the corridor is ‘high risk’ due to disturbance, however, ability for elephants to still use the corridor suggests that the needs of humans and wildlife can be met through temporal separation of land use. Land for the corridor was provided by local farmers and so sustaining community support is paramount for maintaining the corridor.
Acknowledgements
I would like to thank the Mount Kenya Trust ,Lewa Wildlife Conservancy and Lewa Research Department for their assistance and expertise.
Fig.6 Crossing at night to avoid humans and cattle
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