Taking the Elephant out of the Room and Into the Corridor: Can Urban Corridors Work?

Taking the elephant out of the room and into the corridor: can urban corridors work?

T EMPE S. F. ADAMS,MICHAEL J. CHASE T RACEY L. ROGERS and K EITH E. A. LEGGETT

Abstract Transfrontier wildlife corridors can be successful Introduction conservation tools, connecting protected areas and reducing the impact of habitat fragmentation on mobile species. uman population increase has resulted in increased Urban wildlife corridors have been proposed as a potential Hfragmentation of wildlife habitat (Johnsingh &   mitigation tool to facilitate the passage of elephants through Williams, ; Osborn & Parker, ) and consequently towns without causing conflict with urban communities. the formation of isolated protected areas (the so-called is- However, because such corridors are typically narrow and land effect). The lack of connectivity between protected close to human development, wildlife (particularly large areas can have a negative impact on wildlife, particularly mammals) may be less likely to use them. We used re- on large, wide-ranging species (Hilty & Merenlender,   mote-sensor camera traps and global positioning system ; Kuykendall & Keller, ). Wildlife corridors that  collars to identify the movement patterns of African ele- connect favoured habitats (Caro et al., ; Mangewa  phants Loxondonta africana through narrow, urban corri- et al., ) are potentially a solution to the problem, al- dors in Botswana. The corridors were in three types of though their value has been debated (Hilty &  human-dominated land-use designations with varying le- Merenlender, ). To date, research has concentrated vels of human activity: agricultural, industrial and open- on the value of transfrontier connections through human- space recreational land. We found that elephants used the modified landscapes, linking protected wildlife areas   corridors within all three land-use designations and we (Osborn & Parker, ; Douglas-Hamilton et al., ;  identified, using a model selection approach, that season, Mangewa et al., ), and creating vital links between pro-  time of day and rainfall were important factors in determin- tected areas and resources (Gilbert et al., ; Hilty &   ing the presence of elephants in the corridors. Elephants Merenlender, ; Caro et al., ; Mangewa et al.,  moved more slowly through the narrow corridors compared ). However, there is a need for a better understanding with their movement patterns through broader, wide-ran- of wildlife movements at a smaller spatial scale, through ging corridors. Our results indicate that urban wildlife cor- urban settlements in or adjacent to wildlife protected areas  ridors are useful for facilitating elephants to pass through (Carter et al., ), where the passage of wildlife is facilitated – urban areas. by narrow ( m) pathways. Human encroachment on and around wildlife pathways is an important driver of Keywords Camera traps, conservation, human–elephant human–wildlife conflict (Carter et al., ;Songhurst& coexistence, land management, urban wildlife corridors Coulson, ), which inevitably occurs when people and  To view supplementary material for this article, please visit wildlife come into direct contact (Sitati et al., ;Graham    http://dx.doi.org/./S et al., ; Carter et al., ; Runge et al., ;Songhurst et al., ). However, securing space for wildlife to pass unimpeded through community areas could facilitate coexistence and potentially offer a long-term solution to conflict. The small-scale movement of wildlife through human settlements is relatively unexplored (Carter et al., ) but is increasingly important as human populations increase and people come into closer contact with wildlife. TEMPE S. F. ADAMS* (Corresponding author) and KEITH E. A. LEGGETT Fowlers Gap Arid Zone Research Station, Centre of Ecosystem Science, School of The design and implementation of a wildlife corridor in Biological Earth and Environmental Sciences, University of New South Wales, an urban setting involves particular constraints. The use of Australia. E-mail [email protected] corridors by wildlife depends on the availability of appropri- MICHAEL J. CHASE Elephants Without Borders, Kasane, Botswana ate habitat cover that provides browsing material and a TRACEY L. ROGERS Evolution & Ecology Research Centre, School of Biological means of avoiding predators (Newmark, ); for example, Earth and Environmental Sciences, University of New South Wales, Australia the eland Taurotragus oryx, the greater kudu Tragelaphus *Also at: Elephants Without Borders, Kasane, Botswana, and Evolution & strepsiceros and the lesser kudu Tragelaphus imberbis are Ecology Research Centre, School of Biological Earth and Environmental Sciences, University of New South Wales, Australia sensitive to human-altered landscapes that lack resources Received  August . Revision requested  September . for predator avoidance, and therefore thick habitat coverage Accepted  October . First published online  May . is critical to their use of a corridor (Newmark, ). The

This is an Open Access article, distributed under the terms of the Creative Commons Attribution licence Downloaded(http://creativecommons.org/licenses/by/4.0/), from https://www.cambridge.org/core. IP whichaddress: permits 170.106.35.234 unrestricted, on re-use, 01 Oct distribution, 2021 at 16:25:11 and reproduction, subject to in the any Cambridge medium, provided Core terms the original of use, work available is properly at cited. https://www.cambridge.org/core/termsOryx, 2017, 51(2), 347–353 ©. https://doi.org/10.1017/S00306053150012462016 Fauna & Flora International doi:10.1017/S0030605315001246 348 T. S. F. Adams et al.

 success of a corridor may also depend on the terrain, the settlement in the , km Chobe District, in north- human population density (Roever et al., ) and the loca- eastern Botswana (Fig. ); % of the Chobe District is for- tion of roads (Kuykendall & Keller, ), as well as the prox- mally protected (% in Chobe National Park and %as imity, size and land use of human settlements (Songhurst forest reserve). et al., ) People may be perceived as a threat and may Chobe District is bordered to the north by Namibia and also compete directly with wildlife for resources (Head Zambia, and to the east by Zimbabwe. Kasane and et al., ; Songhurst et al., ). Kazungula lie between the Chobe/Zambezi River and the We do not know how species will use human-shared ha- protected areas of Chobe National Park and Chobe Forest bitats and whether or not coexistence in compact areas is a Reserve. The human population of Chobe District increased viable conservation option, especially for large mammals by .% during – (Census Office, ) and is set (Carter et al., ; LaPoint et al., ). There are concerns to continue increasing. Kasane and Kazungula are the two about the impact of habitat fragmentation on large mammals largest human settlements in the northern region of the ele- and how they operate at broad spatial scales (LaPoint et al., phant’s range, with a combined population of c. , peo- ;Roeveretal.,). We do not know if they can function ple (Census Office, ), and a density of  people per  alongside people at small spatial scales (Patterson, ; km . There is no standardized definition of what constitutes Wright & Coleman, ; Carter et al., ), as they require an urban area (Brenner & Schmid, ) but Kasane and a large home range for food resources (Kelt & Van Vuren, Kazungula are categorized as urban based on their increas- ;Jetzetal.,; Tucker et al., ). For migratory spe- ing populations and the availability of amenities and ser- cies, understanding their movement patterns is vital for their vices (Joos-Vandewalle, ). conservation; to understand the challenges that will be faced The elephant population in Chobe District is estimated in securing their future, one must first understand where they to be c. , (Chase et al., ), with c. , in Chobe go (Runge et al., ). The African elephant Loxodonta afri- National Park. Elephants pass through Kasane and cana is an ideal model species as it is large, wide ranging and Kasungula en route from the Park and forestry reserves to terrestrial, and often co-occurs with other species of conser- the river. Both communities are located on the banks of vation concern (Roever et al., ). Elephants are known to the Chobe River, which is a perennial river system that use wildlife corridors and pathways through human-modified joins the Kwando–Linyanti and Zambezi river systems. landscapes when moving between protected areas or to access Northern Botswana is semi-arid with a sub-tropical climate resources (Douglas-Hamilton et al., ; Graham et al., and four seasons: the cold dry season (May–July), the hot dry ;Songhurstetal.,). However, we have limited season (August–October), the wet season (November–March) knowledge of their use of smaller corridors that pass directly and the post wet season (April), when the rains have stopped through human settlements (Head et al., ). but the majority of natural pans away from permanent water Botswana is home to the largest population of African ele- sources are still full (Clark, ). The rainfall data used in this phants (c. ,;Chaseetal.,)aswellasarapidly study were obtained from the Government of Botswana increasing human population (.%increaseduring– Bureau of Meteorology, Kasane Station (Government of ; Census Office, ). Human settlements within the ele- Botswana, ). phant’s range are located close to resources such as rivers and nutrient-rich soils, which are used by both wildlife and people. This overlap poses a challenge in managing the increasing Methods humanpopulation(Chase,), and requires the establish- ment of better management and land-use practices to facilitate Monitoring coexistence between people and wildlife (Songhurst et al., ). Our objective was to assess whether the African elephant We monitored seven corridors within three designated land would use narrow urban wildlife corridors. We used a series uses over a distance of c.  km (Ministry of Lands, Housing of remote-sensor camera traps, and data from global position- and Environment, ): two are in open space and conser- ing system (GPS) collars, to investigate corridor use in three vation areas (A), three in industrial areas (B) and two in human-dominated land-use types over  years. We predicted agricultural areas (C; Fig. ). The agricultural corridors (C) that elephants would use the corridors in temporal and spatial are designated (i.e. they are acknowledged by the local coun- patterns that minimized their interaction with people. cil on planning maps as areas of wildlife use; Ministry of Lands, Housing and Environment, ), whereas the corridors in land uses A and B are non-designated (i.e. they are Study area not officially planned or acknowledged). All of the corridors have similar geographical attri- The study was conducted in the townships of Kasane and butes, with elephants entering from the forestry reserve Kazungula, which together comprise the largest human and passing through the corridors to access the Chobe

Oryx, 2017, 51(2), 347–353 © 2016 Fauna & Flora International doi:10.1017/S0030605315001246 Downloaded from https://www.cambridge.org/core. IP address: 170.106.35.234, on 01 Oct 2021 at 16:25:11, subject to the Cambridge Core terms of use, available at https://www.cambridge.org/core/terms. https://doi.org/10.1017/S0030605315001246 Use of urban corridors by elephants 349

FIG.1 Wildlife corridors through the Kasane and Kazungula communities in Chobe District, north-eastern Botswana. Corridors A and A pass through open space and conservation areas; B,B and B pass through industrial areas; C and C pass through agricultural areas.

River (Fig. ). The corridors through the open space and continues alongside a private lodge and camp ground; and B conservation area are  m apart and located north of the passes between a lodge and residences (Fig. ). main road. Each runs from outside Kasane to the Seboba To monitor the presence of elephants in the corridors we Recreational Park on the Chobe River, in close proximity installed one Bushnell Trophy Cam Brown HD (c) to a number of local businesses and a commercial develop- camera trap (Bushnell Corporation, Overland Park, USA) ment site. There is a relatively high level of human activity in in each corridor (Carter et al., ; LaPoint et al., ). the Seboba Recreational Park, which is used for fishing, re- Cameras were attached to trees or posts, c. .–. mabove ligious ceremonies and other cultural activities. There is a the ground and facing paths used by wildlife, and remained fence along the main road, in which two gaps have been in the same position throughout the study. Photographs were opened for corridors A (lengthc. m, minimum width downloaded from the memory cards each week. Four of the c.  m; Supplementary Plate S)andA (length c.  m, cameras (A,A,C and C) were deployed in November minimum width c.  m), and this is the narrowest part of  for  months, two (B and B) in February  for  the corridors. We set one camera on each of these corridors months, and one (B)inApril for  months. Cameras to record any movement of elephants through the gaps in operated continuously for  hours per day and recorded the fence. photographs at  s intervals when triggered by movement, The agricultural corridors are located between Kasane until the detected target was out of range (c.  mfromthe and Kazungula, in an area known as the Seep (Fig. ). The camera). For each photograph we recorded the time, date and Kazungula highway runs directly through the area, with the number of species captured. Chobe River flowing adjacent to the road. The corridors C The NGO Elephants Without Borders fitted a mature (length c. , m, minimum width c.  m) and C (length adult cow (CH )intheKasane–Kazungula region and a c. , m, minimum width c.  m) run alongside the two mature bull elephant (CH ) on the Chobe riverfront within largest commercial farms in the Kasane area. The end point Chobe National Park with GPS satellite collars (African of both corridors is a natural hot spring (the Seep) that Wildlife Tracking, Pretoria, South Africa). The collars were opens onto the river, which is a popular recreational site set to record the location of the elephants every hour. We at weekends. used data recorded during  October – October , Unlike in the other two land-use areas, the three corridors which coincides with the period of camera trapping. monitored in industrial areas (B: length c.  m, minimum width  m; B:lengthc. m, minimum width  m; B:    length c. , m, minimum width m) are not located Statistical analysis alongside one another (Fig. ). B is a narrow, fenced corridor between Seboba Recreational Park and a jail farm; B is a nar- We recorded a single count of presence () or absence () for row, fenced passage between two government offices, which each day in each corridor, depending on whether or not

TABLE 1 The summary statistics for each of the generalized linear mixed models in which daily presence/absence of elephants Loxodonta africana was the response variable, with model parameters, corrected Akaike information criterion (AICc), ΔAIC, AIC weight, and evidence ratio. Parentheses indicate random factors.

Model no. Model parameters AICc ΔAIC AIC weight Evidence ratio 1 Season + (Rainfall) + (Corridor) 2,854.40 0.00 1.00 1.00e + 00 2 Season + Width + (Year) + (Corridor) 2,900.60 46.20 0.00 1.07e + 10 3 Season + Day of the week + (Year) + (Corridor) 2,918.34 63.94 0.00 7.67e + 13 4 Season + Width + (Corridor) 2,920.08 65.68 0.00 1.83e + 14 5 Season + Width + Day of the week + (Corridor) 2,928.76 74.37 0.00 1.40e + 16 6 Land designation + Season + (Corridor) 2,934.05 79.65 0.00 1.97e + 17 7 Land designation + (Rainfall) + (Corridor) 2,956.89 102.49 0.00 1.79e + 22

TABLE 2 The summary statistics for each of the generalized linear mixed models in which hourly presence/absence of elephants was the response variable, with model parameters, corrected Akaike information criterion (AICc), ΔAIC, AIC weight, and evidence ratio. Parentheses indicate random factors.

Model no. Model parameters AICc ΔAIC AIC weight Evidence ratio 1 Hour + Land designation + Season + (Corridor) 1,352.52 0.00 1.00 1.00e + 00 2 Season + Width + (Traffic) + (Corridor) 1,368.99 16.47 0.00 3.77e + 03 3 Season + (Traffic) + (Corridor) 1,379.43 26.91 0.00 6.97e + 05 4 Land designation + Season +(Traffic) + (Corridor) 1,381.33 28.81 0.00 1.80e + 06 5 Land designation + (Traffic) + (Corridor) 1,450.86 98.34 0.00 2.26e + 21 6 Season + (Corridor) 1,660.21 307.69 0.00 6.53e + 66 7 Land designation + Season + (Traffic) + (Corridor) 1,661.91 309.39 0.00 1.52e + 67

elephants were photographed. We calculated zero inflation Results and overdispersion in the data, and selected the appropriate   family function. To determine if and how elephants used the We recorded a total of , images of elephants across the   urban corridors we created seven binomial generalized lin- seven corridors over a -day period during November –  ear mixed models in Rv... (R Development Core Team, April . Both bulls and breeding herds with ’ ), using the lme, MASS and NLME packages, to inves- young calves were recorded. Elephants daily and hourly tigate which factors influenced elephants’ daily usage of the use of the corridors followed a temporal pattern on hourly,   corridors (Underwood, ). Elephant presence in a corri- daily, seasonal and annual scales (Tables & ). Other spe-   dor was tested as a function of land-use designation, corri- cies were also detected in the corridors. Camera B (Fig. )  dor, day, corridor width, season, rainfall and year. Corridor, recorded the highest species diversity, with species, ran- rainfall and year were random factors (Underwood, ). ging from small carnivores, such as civets Civettictis civetta, Model selection was based on Akaike’s information criter- to buffalo Syncerus caffer. ion (AIC; Burnham et al., ); the lower the AIC score, the better the model. Summary function was used for the re- Daily corridor usage The presence of elephants in the sult output. Significance was determined for all analyses at corridors was influenced significantly by season and ,   P . . rainfall (Table , Fig. , Supplementary Table S). The ’ To identify the factors that influenced elephants highest usage was in August, with a mean of  ± SE  finer-scale movements in the corridors we examined data detections per day, followed by April, with  ± SE . on an hourly time scale. Presence or absence was recorded Activity increased significantly in the post wet (z = .,  in -hourly time intervals for each month. We used bino- SE = .,P, .), hot dry (z = .,SE=., mial generalized linear mixed models in which the fixed fac- P , .) and wet (z = .,SE=.,P, .) seasons  tors were hour ( -hourly interval), season, land-use in each of the land-use designations (Fig. ). There was a designation, and width of corridor; corridor and traffic negative relationship between rainfall and elephant  were random factors (Underwood, ). Traffic was mea- presence. sured by counting all vehicles along the highway during a randomly selected -minute period every hour. The -minute counts were averaged for -hourly blocks and Hourly usage Elephants were active in each of the used as an indicator of road usage in the area. corridors in each land-use designation throughout the day

suggesting they were actively managing the amount of time they spent in unprotected areas (Graham et al., ). Our camera trap photographs showed that both bulls and family units with small calves used the urban corridors, whereas previous research has shown females and calves avoiding community areas (Von Gerhardt et al., ). The collared cow, a member of a family unit, used the corridors more frequently than the collared bull, and moved through them more slowly, on average. Corridor width was not shown to have a significant effect on elephant presence; however, the shape of a corridor could potentially im- pede or impact its use by elephants and thus could play an important role in determining the corridor’s success. On average, the lowest number of elephants was detected in corridor B, a long and narrow fenced pathway that passes

FIG. 2 Mean (± SE) number of elephants Loxodonta africana through the corridor to the river. detected per day in wildlife corridors through agricultural, Seasons were shown to affect the temporal patterns of industrial, and open land in the townships of Kasane and urban corridor use by elephants. The mean daily usage Kazungula (Fig. ), in the cold dry, hot dry, post wet and wet reached a peak in the post wet season, coinciding with the seasons. peak of the Chobe River flood. The elephants may have been browsing on the available vegetation before the start  and night, with a diel pattern of use (Fig. ). Hour, season of the dry season. Corridor use was also high during the and land-use designation influenced elephant presence in hot dry season, possibly because the elephants needed to ac-  all corridors (Table ). More elephants were observed in cess the river more often to stay hydrated.    the evening (Fig. ; Table , Supplementary Table S ), and Rainfall was a significant factor in the daily usage model, activity in the corridors was significantly higher at night with reduced elephant presence in the corridors during the  –   –   ( . . ) than during the day ( . . ; Table ). wet season. Rainfall is linked to increased availability of food   More elephants were observed in the post wet (z = . , and water resources in the national park and forestry re-   ,       SE = . ,P . ) and hot dry (z = . ,SE=. , serves, and feeds water into natural pans, thus reducing ,   P . ) seasons than in other seasons. the need for elephants to use the corridors to access the river (Birkett et al., ). ’ Movement of collared elephants Each of the two GPS Elephants hourly usage of the corridors followed a diel satellite-collared elephants used the camera-monitored pattern, with increased elephant presence at night, when ele- corridors during the year of the study. The cow (CH ) phants are less likely to come into contact with people. This moved into the town in the wet and post wet seasons. The behaviour is consistent with previous studies of elephant oc-  bull (CH ) came into the town at the end of the hot dry cupation of community areas (Sitati et al., ; Graham   season and stayed until the start of the wet season, and then et al., ; Songhurst & Coulson, ). returned in February, March, May and July. They each Vehicular traffic in the corridors was used as a variable to passed through different corridors in Kasane and measure the impact of human activity on elephant presence. Kazungula, moving at similar speeds, and the cow used We found opposing trends in road use and elephant presence the corridors more frequently (Table ). in each of the land-use designations: traffic density was higher between sunrise and sunset, and elephant presence was higher between sunset and sunrise. However, the rate of traffic did not have a significant impact on elephant presence in any of Discussion the corridors. Previous studies found that the construction of roads acted as a barrier to the movement of forest elephants in Elephants used the monitored corridors throughout the year, both protected and unprotected areas (Blake et al., ), and showing temporal patterns of use on both hourly and season- that elephants avoided segments of a road passing through a al scales. Land-use designation did not strongly influence ele- protected area, where there was a higher density of vehicular phants’ daily use of the corridors but it influenced their traffic. We observed the opposite, in that elephants readily hourly usage. This finding complements the results of crossed the highway to reach the river, although they tended Douglas-Hamilton et al. () and Graham et al. (), to use the corridors in the evening, when there was less traffic. who reported that elephants moved through unprotected It has been suggested that the only way to know if a corridor areas more quickly and spent less time in those areas, is functional is to block it and see what happens (Mann &

FIG. 3 Mean (± SE) number of elephant detections in wildlife corridors through (a) agricultural, (b) industrial, and (c) open land in the townships of Kasane and Kazungula (Fig. ) during -hourly intervals, with mean vehicle density (a), based on recording the number of vehicles using the corridors during a randomly selected -minute slot each hour.

TABLE 3 The mean, maximum and minimum speeds at which two Park, to facilitate the passage of elephants through the elephants fitted with GPS satellite collars passed through urban Park. Formal protection and designation of urban corridors wildlife corridors in the townships of Kasane and Kazungula, in by the relevant governing bodies would facilitate coexistence  north-eastern Botswana (Fig. ), and the number of visits by each between people and wildlife at small spatial scales. elephant.

CH 67 CH 60 Acknowledgements (mature cow) (mature bull) − Mean speed (km h 1) 0.54 ± SE 0.06 0.50 ± SE 0.18 − We thank Elephants Without Borders for allowing the re- Max. speed (km h 1) 1.66 1.43 − search to be conducted under their research permit in Min. speed (km h 1) 0.07 0.01 Botswana, and the Paul G. Allen Family Foundation and No. of visits 27 7 C. Bargmann for financial assistance. The research has been approved by the Botswana Government under the re-  Plummer, ).Priortothisstudyafencewaserectedbythe search permit EWT // XX (), granted by the Seboba Recreational Park across the open space where corri- Department of Wildlife and National Parks to Elephants    dors A and A were created (Fig. ). Elephants were unable Without Borders. We thank M. Scott, R. Sutcliffe, to gain access to the river and caused damage to the fence, J. Halstead and M. Portek for their assistance in the field  knocking down parts of it (Supplementary Plate S ). The cor- and with data input; S. McLeod, J. Smith, R. Hartley and ridors were then established so the elephants could pass S. Brodie for their assistance with statistics; and R. Palmer through the fence unimpeded, and they caused no further and D. Clarkson for their assistance with editing. damage. This example highlights the importance of urban corridors in minimizing conflict between people and elephants. Developing countries balance their development goals References with their wildlife conservation objectives (Johnsingh & Williams, ). It is vital for Botswana to implement appro- BIRKETT, P.J., VANAK, A.T., MUGGEO, V.M.R., FERREIRA, S.M. & SLOTOW,R.() Animal perception of seasonal thresholds: priate management strategies, such as urban corridors, to changes in elephant movement in relation to rainfall patterns. PLoS maintain and preserve Africa’s largest remaining elephant ONE, (), e. population as urban development proceeds. Our results BLAKE, S., DEEM, S.L., STRINDBERG, S., MAISELS, F., MOMONT, L., show the functionality of urban corridors in facilitating ISIA, I.-B. et al. () Roadless wilderness area determines forest    the passage of elephants through community areas, and it elephant movements in the Congo Basin. PLoS ONE, ( ), e . BRENNER,N.&SCHMID,C.() The ‘Urban Age’ in question. is possible that such corridors could also be used by other International Journal of Urban and Regional Research, , –. wildlife species. The results have been incorporated in the BURNHAM, K.P., ANDERSON, D.R. & HAYVAERT, K.P. () AIC wildlife management plan for the Seboba Recreational model selection and multimodel inference in behavioral ecology:

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The American focused on the status of elephant populations in Botswana and neigh- Naturalist, , –. bouring countries, and their migratory and cross-border movement KUYKENDALL, M.T. & KELLER, G.S. () Impacts of roads and behaviour. TRACEY ROGERS’ research aims to understand ecological corridors on abundance and movement of small mammals on the patterns in mammals, specifically in relation to the ecological and evo- Llano Estacado of Texas. The Southwestern Naturalist, , –. lutionary consequences of being a certain size, and adopting a foraging LAPOINT, S., GALLERY, P., WIKELSKI,M.&KAYS,R.() Animal or locomotory strategy. KEITH LEGGETT is a spatial ecologist and is behavior, cost-based corridor models, and real corridors. Landscape primarily interested in movement biology. He worked on the desert Ecology, , –. elephants in north-west Namibia for many years, where he focused MANGEWA, L.J., KIKULA, I.S. & LYIMO, J.G. () Ecological viability on elephant movement ecology and human−elephant conflict mitiga- of the upper Kitete–Selela wildlife corridor in the Tarangire– tion in arid environments.