Vulnerability of small and medium-sized prey mammals in relation to their habitat preferences, age classes and locomotion types in the temperate Monte Desert, Argentina

Abstract

a b s t r a c tIn this study we examined predation by small felids upon small and medium-sized prey mammals in the central region of the Monte Desert. We analyzed the degree of vulnerability of prey mammals in relation to their habitat use patterns, modes of locomotion and age classes. Medium and small rodents were the predominant prey in the diet of small cats. The most consumed small mammal was Akodon molinae, which inhabits areas of dense cover, while species occurring in open habitats such as Eligmodontia typus were less consumed. Among medium-sized mammals, Galea leucoblephara that depends on patches with high plant cover for refuge was more consumed than Microcavia australis that lives in colonies and displays a complex set of antipredator strategies. Prey selectivity on small rodents showed that E. typus, which uses bipedal locomotion and an erratic escape behaviour, was consumed in greater proportion than its availability. We suggest that although its specialized locomotory mode would diminish predator attacks, its preference for open habitats would increase the probability of predator-prey encounter. Consumption of small mammals focuses mostly on adult individuals. However, we found a significant consumption of senile individuals of A. molinae, which points out that vulnerability tends to be high towards the age of maturity in this species.

Behavioural and morphological strategies by small savannah rodents to avoid predation

“…Vásquez (1996) and Taraborelli et al (2003) described the Chilean Oligoryzomys longicaudatus using bipedal locomotion when escaping and quadrupedal locomotion when moving at a slow speed or over short distances. Corley et al (1995) also described similar ability in Eligmodontia typus, which was consumed less than expected by foxes (Dusicyon culpaeus) in Chile; however, Bisceglia et al (2011) and Tabeni et al (2012) reported a positive selection for Eligmodontia typus by small felids in Argentina. In this latter case, E. typus is reported to use open (and risky) habitats.…”

“…An efficient defence strategy not only involves a good hearing, visual or olfactory capability to detect the predator in advance but also a successful escape mechanism, such as bipedal hopping (Kotler 1984;Djawdan and Garland 1988;Hughes et al 1994;Taraborelli et al 2003;Bisceglia et al 2011;Tabeni et al 2012), which may interrupt the predation sequence (sensu Endler 1986) as the predator is approaching. The Brazilian Sigmodontines include several quadrupedal species of different sizes.…”

“…Hopping, digging, jumping and ground activities are strategies used by other Echimyidae species (Manaf and Oliveira 2000) and by subterranean tuco-tucos (Ctenomys sp.) against predation (Tabeni et al 2012).…”

“…In the case of small rodents, inflated bullae (Webster 1962;Kotler et al 1988), bipedal locomotion with high running speeds and erratic escapes (zigzagging) (Bartholomew and Cary 1954;Djawdan and Garland 1988;Kotler et al 1988;Corley et al 1995;Taraborelli et al 2003;Tabeni et al 2012), intermittent locomotion (McAdam and Kramer 1998;Kramer and McLaughlin 2001;Vásquez et al 2002;Taraborelli et al 2011), lower activity on full moon nights (Clarke 1983;Simonetti 1989;Daly et al 1992;Hughes and Ward 1993;Hughes et al 1994;Vásquez 1994;Orrock et al 2004;Upham and Hafner 2013), use of bushy microhabitats (Price et al 1984;Kotler et al 1988;Pusenius and Ostfeld 2002;Orrock et al 2004;Bisceglia et al 2011;Tabeni et al 2012 and Caswell 1951) and group-living (Yáber and Herrera 1994;Ebensperger and Wallem 2002) are all described as efficient antipredator strategies.…”

“…Studies on small mammal prey selection by raptors and carnivores revealed that prey size (Marti and Hogue 1979;Bueno and Motta-Junior 2008), colouration (Kaufman 1974;Ruggiero et al 1979), age and sex (Longland and Jenkins 1987;Derting and Cranford 1989;Dickman et al 1991), level and patterns of locomotion (Kotler 1985;Corley et al 1995;Taraborelli et al 2003;Tabeni et al 2012), social position (Brown and Twigg 1971;Roberts and Wolfe 1974) as well as prey community and population parameters, such as richness and abundance (Jaksic and Simonetti 1987), may play a role in predator choice (Derting and Cranford 1989).…”