Using camera trapping to estimate occupancy of leopards (Panthera pardus) and spotted hyaenas (Crocuta crocuta) in Nyika National Park, Malawi.

1. Simpsons diversity index (D) was calculated for the study
areas from camera trap photographs. Presence (detection)
and absence (non-detection) were modelled as a binary
response to independent leopard and spotted hyaena
photographs (events) recorded at each camera trap station (fig.2). Occupancy
(Ψ) and detection (p) were analysed using PRESENCE (V. 12.6) [6-7] and
modelled with six covariates (i) habitat type; (ii) plant diversity; (iii) presence of
opposed carnivore; (iv) presence of mesocarnivores; (v) diversity of
ungulates; and (vi) overall diversity. Hyaena occupancy models were ranked
by AIC values. Leopard occupancy data was over-dispersed, so adjustments
were made to the variance inflation factor (ĉ), and models were ranked by
quasi-AIC (QAIC) values. Models with ΔAIC/ΔQAIC values >2 were excluded
as having little or no support [8-9]. Outputs of site specific estimates of
occupancy were mapped using inverse distance weighting in ArcGIS Pro (V.
2.0.1) [10].
strength of ecosystem function [2]. Leopards (Panthera pardus) and spotted
hyaena (Crocuta crocuta) are both species of concern, facing population
decline and range loss from anthropogenic influence [3-5]. This study aims to
investigate: a) the interactions between overall species diversity and the
diversity of vegetation, prey and carnivores and b) how they influence
occupancy (locations where the species are present) of leopards and
spotted hyaena, through the use of camera trapping, GIS
and occupancy analysis.
Using camera trapping to estimate occupancy of leopards (Panthera pardus) and
spotted hyaenas (Crocuta crocuta) in Nyika National Park, Malawi. Beth Byrne
MSc Endangered Species Recovery and Conservation 2016/2017
Nottingham Trent University, School of Animal, Rural and Environmental Sciences
Spotting patterns of carnivore distribution
ba
Figure 2: Camera trap photos of (a) leopard and (b) spotted hyaena in NNP
Discussion
Camera trapping can only confirm presence of a species,
assuming absence will only lead to biased estimates [11].
Occupancy analysis overcomes this non-detection bias. The results show
that although there is a low species diversity across the whole study area,
there is a significant positive relationship between both apex predators and
species diversity, and a significant positive relationship between ungulates
and leopards. As many of the models were removed, most variables could
not be fully explored. However, mapped areas of occupancy can provide
useful insights on areas where these two species are present, as a direction
to target conservation efforts and monitoring programmes. This study
demonstrates the interdependence of carnivores, biodiversity and ecosystem
function. It provides the first-ever occupancy estimates for leopards and
spotted hyaenas in NNP including identification of two new leopards. It
confirms camera trapping is highly appropriate for collecting occupancy data
and, despite some suggested improvements to the study design due to a lack
of detections, the results can help inform future conservation management
decisions and offer a framework and direction for further study.
MethodologyBackground and Aims
Study Area
Understanding biodiversity is a pre-requisite to wildlife
conservation and decreasing species extinction rates [1].
The presence of apex predators in an ecosystem strongly
correlates with high biodiversity and influences the
Figure 1: the study area and camera trap placement within NNP.
Figure 3: results of the study showing the
probability that a site is occupied across the
study area using models with different
covariates: (a) occupancy of hyaena when
modelling species diversity, (b) occupancy of
leopards when modelling diversity of
ungulates and (c) occupancy of leopards
with overall species diversity as a covariant.
Areas with a high probability of occupancy
(≤0.9) are highlighted in red and low
probabilities of occupancy (≤0.2) are
highlighted in green.
a
c
b
Results
In 640 trap nights, 369 events were obtained. Overall trapping
success (TS) was 57.66 per 100 trap nights (TN). From 8
cameras, 11 leopard events were recorded (TS= 1.72 per 100
TN). From 10 cameras, 22 spotted hyaena events (TS= 3.44 per 100 TN).
Low TS led to a low sample size. Simpson’s diversity index across the study
area was low (1-D=0.166). Hyaenas: overall species diversity has has a
positive relationship between species diversity and hyaena occupancy [Ψ =
2.494 ± 1.0503 SE] (fig.3a). Leopards: a) positive relationship between the
diversity of ungulates and the presence of leopards [Ψ = 1.999 ± 1.178 SE]
(fig.3b) and b) positive relationship between overall species diversity and the
presence of leopards [Ψ = 1.883 ± 0.945 SE] (fig.3c). This data shows that
there is a correlation with overall species diversity and presence of apex
carnivores.
References: [1] Groves, C.R., Jensen, D.B., Valutis, L.L., et al., 2002. Planning for biodiversity conservation: putting conservation science into practice. Bioscience, 52, pp. 499–512. [2] Ripple, W., Estes, J., Beschta, R., et al., 2014. Status and ecological effects of the world’s largest carnivores. Science, 343(6167), pp.1241484. DOI 10.1126/science.1241484. [3] Ray, J. C., Hunter, L. T. B. and Zigouris, J., 2005. Setting Conservation and Research Priorities for Larger
African Carnivores. WCS Working Paper 24. New York: Wildlife Conservation Society. [4] Jacobson, A.P., Gerngross, P., Lemeris Jr, J.R., et al., 2016. Leopard (Panthera pardus) status, distribution, and the research efforts across its range. PeerJ, 4, pp. e1974; DOI 10.7717/peerj.1974. [5] Ceballos, G., and Ehrlich, P.R., 2002. Mammal population losses and the extinction crisis. Science, 296(5569), pp. 904-907. [6] Hines, J.E., 2017. PRESENCE 12.6-Software to estimate
patch occupancy and related parameters. USGS-PWRC. [7] MacKenzie, D., Nichols, J,D., Royle, J.A., Pollock, K,H., Bailey, L.L., Hines, J.E., 2006. Occupancy Estimation and Modelling: Inferring Patterns and Dynamics of Species Occurrence. Academic Press, London, UK. [8] Anderson, D.R., and Burnham, K.P., 2002. Avoiding pitfalls when using information-theoretic methods. The Journal of Wildlife Management, 66, pp. 912-918. [9] Yarnell, R.W., Pacheco, M.,
Williams, B., et al., 2014. Using occupancy analysis to validate the use of footprint tunnels as a method for monitoring the hedgehog Erinaceus europaeus. Mammal Review, 44, pp. 234-238. [10] ESRI 2017. ArcGIS Pro: Version 2.0.0.8933. Redlands, CS: Environmental Systems Research Institute. [11] Henschel, P., and Ray, J. C., 2003. Leopards in African Rainforests: Survey and Monitoring Techniques, pp. 54. Wildlife Conservation Society, Global Carnivore Program,
New York.
The study took place in Nyika National Park (NNP) Malawi
between 1st June and 17th July 2017. The park is a 3200 km2
protected area with a complex vegetation including undulating
grasslands, pine plantations and afromontane forest. 32 camera traps were
placed in a 250 km2 area on the Nyika plateau (>1800m). Cameras were
placed using systematic random sampling, radiating outwards along roads
and trails from Chelinda (fig.1).