Seed dispersal potential of jackals and foxes in semi-arid habitats of South Africa

Abstract

We determined the consumption of fruits and estimated potential seed dispersal of a canid community in semi-arid ecosystems of South Africa by comparing diets, defecation sites, densities and potential seed shadows of cape foxes (Vulpes chama), bat-eared foxes (Otocyon megalotis) and black-backed jackals (Canis mesomelas) on Benfontein and Rooipoort nature reserves. On Benfontein, all canid species consumed the fruit of Diospyros lycioides throughout the year. Jackals, but neither fox species, consumed relatively large amounts of Prosopis spp.(mesquite), an alien invasive. On Rooipoort, jackals had relatively high consumption of Ziziphus mucronata, followed by Grewia flava and D. lycioides. Bat-eared foxes had high consumption of fruit per area, although their seed dispersal potential was low due to their small potential seed shadow and poor germination sites. Cape foxes had the largest potential seed shadow, but their seed dispersal potential was low because of low fruit consumption, low density, and poor germination sites. Jackals had the highest seed dispersal potential because they consumed the most fruit species, had moderate densities, a relatively large potential seed shadow, and mostly

Frugivory by carnivores: Black‐backed jackals are key dispersers of seeds of the scented !nara melon in the Namib Desert

“…This is consistent with a study by Kamler et al. (2020) in a different region of southern Africa which showed that fruit consumption by black‐backed jackals was higher than that by cape foxes. It is possible that carnivores are generally important for dispersing seeds of African cucurbits as Mills and Mills (1978) noted that brown hyaenas in the Kalahari frequently consume the cucurbits Acanthsicyos naudinianus (gemsbok cucumber) and Citrillus lanatus (tsama melon).…”

“…Carnivore species implicated in seed dispersal include coyotes ( Canis latrans ) in north temperate regions (Willson, 1993), Asiatic black bears ( Ursus thibetanus ) in cool temperate deciduous forests (Koike et al., 2008), red and corsac foxes ( Vulpes vulpes and Vulpes Corsac , respectively) in the Mediterranean (Juan et al., 2006; Rosalino, Rosa, & Santos‐Reis, 2010) and in Mongolia (Murdoch et al., 2009). In semi‐arid areas of South Africa, cape foxes ( Vulpes chama ), bat‐eared foxes ( Otocyon megalotis ) and black‐backed jackals ( Canis mesomelas ) have been suggested to have potential as seed dispersers (Kamler et al., 2020). However, the potential of carnivores as seed dispersers in hyper‐arid desert environments has been largely overlooked.…”

“…For instance, it is not known whether jackals are opportunistic dispersers or whether they actively and selectively search for ripe !nara fruit using olfaction. Frugivory by carnivorous mammals has previously been reported mainly on the basis of scat analyses (Kamler et al., 2020; Santos et al., 2003; Silva et al., 2005; Varela & Bucher, 2006). Direct observations of fruit removal by carnivores that are shy and often nocturnal are extremely challenging, but the advent of camera trapping has made it possible to obtain unbiased observations of fruit removal by animals (Kiepiel & Johnson, 2019; Prasad et al., 2010).…”

Home range, habitat selection, density, and diet of golden jackals in the Eastern Plains Landscape, Cambodia

“…Scats of jackals were distinguished from other species based on size, placement, and DNA analysis of selected scats. Jackals typically defecate on elevated objects, such as small shrubs and tufts of grass, that line trails or dirt tracks ( Macdonald 1979 ; Kamler et al 2020a ), rather than directly on the paths themselves. We took a random sample of 10 putative jackal scats collected from shrubs and tufts of grass, and sent them to the Sackler Institute for Comparative Genomics, American Museum of Natural History (New York), who confirmed that the scats were from jackals based on mitochondrial DNA analysis as described by Caragiulo et al (2014) .…”

The dominant role of animal social status in vertebrate seed dispersal

“…Black-backed jackals have the potential to be effective seed-dispersal agents when soft mast, a supplementary resource, is included in individual diets (Do et al 2009;Kamler et al 2020). While it has not yet been evaluated whether individual rank within the dominance hierarchy affects soft mast consumption in this species, it has been shown that rank affects individual space use such that subordinate individuals move farther distances and are more likely to go on extraterritorial forays (Kamler et al 2019), likely increasing the distance that seeds are moved and the diversity of habitats where seeds arrive.…”