Interannual Variation in Diet, Dietary Diversity, and Dietary Overlap in Three Sympatric Strepsirrhine Species in Southeastern Madagascar

Range expansions by generalists can alter communities and introduce competitive pressures on native species. In the Great Basin Desert, USA, coyotes (Canis latrans Say, 1823) have colonized and are now sympatric with native kit foxes (Vulpes macrotis Merriam, 1888). Since both species have similar diets, dietary partitioning may facilitate coexistence. We analyzed coyote and kit fox diets, then compared our results to an earlier study. Because populations are dynamic, we expected that decreases in prey or increases in predator abundance could alter dietary patterns. We found no significant changes in population-level prey diversity for kit foxes or coyotes, but found high levels of dietary overlap between species. We did detect a significant decrease in the relative importance of leporids (family Leporidae) in the diets of both canids, but they remained important for coyotes. The relative importance of small mammals was greater for kit foxes than coyotes, but their importance had not changed significantly over time. We detected significant declines in prey diversity per sample (scat-level dietary diversity) for both canids, suggesting that during a foraging event, individuals may encounter less diverse prey now than historically. These findings suggested that kit foxes and coyotes were not limited by prey, despite high dietary overlap.

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Dietary overlap between sympatric dingoes and feral cats at a semiarid rangeland site in Western Australia

Australian Mammalogy ◽

10.1071/am14038 ◽

2015 ◽

Vol 37 (2) ◽

pp. 219 ◽

Cited By ~ 11

Author(s):

Tim S. Doherty

Keyword(s):

Small Mammals ◽

Western Australia ◽

Small Mammal ◽

Food Item ◽

Dietary Diversity ◽

Dietary Overlap ◽

Mammal Species ◽

Feral Cats ◽

Common Food ◽

Semiarid Rangeland

The diet of sympatric dingoes and feral cats was studied in the semiarid southern rangelands of Western Australia. A total of 163 scats were collected over a period of 19 months. Rabbit remains were the most common food item in cat scats, followed by reptiles, small mammals and birds. Macropod remains were the most common food item in dingo scats, followed by rabbits and birds. Dingo scats did not contain small mammal remains, and infrequently contained arthropod and reptile remains. Cat and dingo scats contained remains from 11 and six mammal species, respectively. Of the small mammals, cat scats contained rodent remains more frequently than those of dasyurids. Dietary diversity of cats was higher than for dingoes and dietary overlap between the two species was relatively low.

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Diet overlap between small ruminants and the European hare in a Mediterranean shrubland

Open Life Sciences ◽

10.2478/s11535-010-0056-7 ◽

2010 ◽

Vol 5 (5) ◽

pp. 729-737 ◽

Cited By ~ 4

Author(s):

Ilias Karmiris ◽

Anastasios Nastis

Keyword(s):

Dietary Diversity ◽

Small Ruminants ◽

Lepus Europaeus ◽

Dietary Overlap ◽

Quercus Coccifera ◽

European Hare ◽

Balanced Diet ◽

Mediterranean Shrubland ◽

Microhistological Analysis ◽

Kermes Oak

AbstractSeasonal diets of goats, sheep and European hares (Lepus europaeus) were examined using microhistological analysis of feces collected when these herbivores grazed together in a typical Mediterranean shrubland. Approximately half of the total diet content of goats was shrubs (mainly kermes oak, Quercus coccifera), while that of hares was grasses (mostly brush grass, Chrysopogon gryllus). Sheep had a more balanced diet consisting mainly of grasses, forbs, and shrubs. Dietary overlap between goats and sheep was high throughout the year. In contrast, there was very low dietary overlap between small ruminants and hares. Dietary diversity was high in spring and low in winter across all species, with sheep in general displaying higher dietary diversity across all seasons than goats and hares. Goats had intermediate and hares had low dietary diversity across all seasons. Communal grazing by small ruminants and hares ensures that there is a more uniform use of the available forage resources than if a single herbivore is left to graze an area.

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Seasonal variation in fish trophic networks in two clear-water streams in the Central Llanos region, Venezuela

Neotropical Ichthyology ◽

10.1590/1982-0224-20160125 ◽

2017 ◽

Vol 15 (2) ◽

Cited By ~ 3

Author(s):

Christopher C. Peterson ◽

Friedrich W. Keppeler ◽

David E. Saenz ◽

Luke M. Bower ◽

Kirk O. Winemiller

Keyword(s):

Seasonal Variation ◽

Food Web ◽

Dietary Diversity ◽

Strong Support ◽

High Water ◽

Water Levels ◽

Fish Assemblage Structure ◽

Dietary Overlap ◽

Clear Water ◽

Trophic Networks

ABSTRACT Food webs are not static entities; consumer resource interactions vary in both time and space, which complicates depiction and comparisons of food web structures. We estimated fish assemblage structure and diets in two clear-water streams in the Venezuelan Llanos region (Charcote and Charcotico) and constructed trophic networks (sub-webs defined by fishes as the principal consumers) during four periods of the annual flood pulse. As stream conditions changed from high-water to low-water, we hypothesized that: 1) the piscivore-non-piscivore ratio would increase; 2) dietary diversity would decrease; 3) interspecific dietary overlap would decline; 4) fewer allochthonous food items would be consumed; and 5) food-web connectance would increase. The piscivore-non-piscivore abundance ratio was higher in both streams during the low-water period. Dietary diversity declined as water levels dropped and availability of aquatic habitats and resources declined, but interspecific dietary overlap was not lower. Contrary to our hypothesis, average interspecific dietary overlap increased at Charcote as the dry season progressed, even though dietary overlap among species was significantly lower than expected by chance. We did not find strong support for our hypotheses regarding seasonal patterns of consumption of allochthonous resources and food web connectance, both of which revealed little seasonal variation.

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Breeding diets of the Little Eagle Hieraaetus morphnoides and Wedge-tailed Eagle Aquila audax in the Australian Capital Territory in 2011–2019

10.20938/afo38019028 ◽

2021 ◽

Vol 38 ◽

pp. 19-28

Author(s):

S.J.S Debus ◽

◽

Jerry Olsen ◽

Susan Trost ◽

Esteban Fuentes ◽

...

Keyword(s):

Intraguild Predation ◽

Niche Breadth ◽

Dietary Diversity ◽

Geometric Mean ◽

Shannon Index ◽

Dietary Overlap ◽

Australian Capital Territory ◽

Australian Capital ◽

European Rabbits ◽

Food Niche

The diets of the Little Eagle Hieraaetus morphnoides and Wedge-tailed Eagle Aquila audax breeding sympatrically in the Australian Capital Territory during 2011–2019 were compared by analysis of pellets and prey remains (six Little Eagle territories and 13 Wedge-tailed Eagle territories; 69 and 49 collections for a total of 232 and 256 prey items, respectively). Little Eagles took 33% mammals (29% European Rabbits Oryctolagus cuniculus), 44% birds, 6% reptiles and 17% insects by number, and 65% mammals (62% Rabbits), 27% birds, 8% reptiles and <1% insects by biomass. Wedge-tailed Eagles took 59% mammals (23% Rabbits and 19% macropods), 38% birds, 1% reptiles, <1% fish and 1% insects by number, and 89% mammals (20% Rabbits, 38% macropods), 10% birds, and <1% reptiles, fish and insects by biomass. Indices of dietary diversity (Shannon Index and Standardised Food Niche Breadth) were 2.57 vs 3.07 and 0.19 vs 0.24, respectively; Geometric Mean Prey Weights (GMPW) were 164 vs 1392 g, but discounting a biased sample of insects in many pellets from two fledglings, Little Eagle GMPW was more like 340 g. Dietary proportions and some metrics for both species appear to have changed little since the preceding decade, although Wedge-tailed Eagle dietary diversity increased slightly and dietary overlap (80%) increased greatly, concomitantly with some pairs of Wedge-tailed Eagles replacing pairs of Little Eagles. Intraguild predation occurred, including Wedge-tailed Eagle predation on Little Eagles.

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