Response of lion demography and dynamics to the loss of preferred larger prey

Abstract

Large carnivores are experiencing range contraction and population declines globally. Prey depletion due to illegal offtake is considered a major contributor, but the effects of prey depletion on large carnivore demography are rarely tested. We measured African lion density and tested the factors that affect survival using mark-recapture models fit to six years of data from known individuals in Kafue National Park (KNP), Zambia. KNP is affected by prey depletion, particularly for large herbivores that were preferred prey for KNP lions a halfcentury ago. This provides a unique opportunity to test whether variables that explain local prey density also affect lion survival. Average lion density within our study area was 3.43 individuals/100 km 2 (95% CI, 2.79-4.23), which was much lower than lion density reported for another miombo ecosystem with similar vegetation structure and rainfall that was less affected by prey depletion. Despite this, comparison to other lion populations showed that age-and sex-specific survival rates for KNP lions were generally good, and factors known to correlate with local prey density had small effects on lion survival. In contrast, recruitment of cubs was poor and average pride size was small. In particular, the proportion of the population comprised of second-year cubs was low, indicating that few cubs are recruited into the subadult age class. Our findings suggest that low recruitment might be a better signal of low prey density than survival. Thus, describing a lion population's age structure in addition to average pride size may be a simple and effective method of initially evaluating whether a lion population is affected by prey depletion. These dynamics should be evaluated for other lion populations and other large carnivore species. Increased resource protection and reducing the underlying drivers of prey depletion are urgent conservation needs for lions and other large carnivores as their conservation is increasingly threatened by range contraction and population declines.

Low-Cost Forensics Reveal High Rates of Non-lethal Snaring and Shotgun Injuries in Zambia's Large Carnivores

“…Our findings on snaring rates in GKE lions were even more alarming; 45% of the GKE lions sampled had been snared at some point in their lifetime. To our knowledge, ours is the first study to quantify snare injuries of lions originating from throughout the GKE although others (Midlane et al, 2014;Overton et al, 2017;Schuette et al, 2018;Vinks et al, 2021a) have reported sightings of Kafue lions with non-lethal snare injuries. Schuette et al (2018) recorded 79 incidences of snare-related injuries to large carnivores in the northern Kafue NP (NKNP) "over the past 5 years" (presumably 2013-2018), but did not specify number of incidents per species, nor whether recorded incidents included repeated sightings of the same individuals.…”

“…Schuette et al (2018) recorded 79 incidences of snare-related injuries to large carnivores in the northern Kafue NP (NKNP) "over the past 5 years" (presumably 2013-2018), but did not specify number of incidents per species, nor whether recorded incidents included repeated sightings of the same individuals. Subsequently, Vinks et al (2021a) reported that 80% (n = 5) of the snare injuries that they encountered in NKNP lions from 2013 to 2018 were young adult (4-5.99 year old) males. Again, while it is possible that snaring in GKE declined after 2012, more recent investigations suggest that poaching increased in the region (Overton et al, 2017;Mkanda et al, 2018).…”

Scavengingvshunting affects behavioral traits of an opportunistic carnivore

“…Despite a frequent emphasis on the effects of the presence or absence of predator on prey ( Salo et al, 2010 ), minimal research has addressed how the loss of prey may impact predator ecology and behavior ( Rodewald, Kearns & Shustack, 2011 ; Newsome et al, 2015a ). Availability of prey has decreased for apex predators globally ( Wolf & Ripple, 2016 ; Vinks et al, 2021 ), although prey resources have increased in some areas ( Prange, Gehrt & Wiggers, 2004 ). Simultaneously, human activity has altered scavenging opportunities ( Yirga et al, 2012 ; Fey et al, 2015 ) and increased access to anthropogenic resources ( Newsome et al, 2015a ; Ciucci et al, 2020 ).…”

LeopardPanthera pardusdensity and survival in an ecosystem with depressed abundance of prey and dominant competitors

“…Because this type of offtake is unregulated, it is often unsustainable, driving extensive wildlife population declines and disproportionately affecting larger-bodied herbivores (Wilkie & Carpenter, 1999; Fa et al, 2000; Creel et al, 2018; Vinks et al, 2020). Herbivore declines, in turn, are widely thought to be a strong driver of carnivore declines in sub-Saharan Africa (Midlane et al, 2014; Rosenblatt et al, 2016, 2019; Creel et al, 2018; Vinks et al, 2021).…”

“…Western Zambia's Greater Kafue Ecosystem, comprising Kafue National Park and surrounding Game Management Areas, has been identified as a potential leopard stronghold, on the basis of historical data (Purchase et al, 2007). Little is known about the current status of leopards in the Greater Kafue Ecosystem, although this system now faces extensive anthropogenic pressures from encroachment (Watson et al, 2014) and illegal offtake (Overton et al, 2017), with effects on the large herbivore and carnivore guilds (Creel et al, 2018; Vinks et al, 2020; Vinks et al, 2021). Specifically, the long-term decline of large-bodied prey species has led to prey base homogenization, niche compression, and increased niche overlap within the large carnivore guild, including of leopards and lions Panthera leo (Creel et al, 2018).…”