A Long-Term Study on the Dynamics of Guild Structure among Predatory Vertebrates at a Semi-Arid Neotropical Site

Jaksić, Fabián M.; Feinsinger, Peter; Jiménez, Jaime E.

doi:10.2307/3545099

Cited by 67 publications

(98 citation statements)

References 30 publications

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“…This pattern may have been facilitated by presence of a high number of small mammals species preyed on by carnivores in the Santa Monica Mountains (n=19; Appendix), and by the fact that temporal and habitat variation of those prey is species-specific (M'Closkey 1972;Meserve 1976;Quinn 1990), thus ensuring that at all sites and seasons some small mammal species were abundant. This proposal is consistent with Wiens (1993) who predicted that for guilds of predators relying on small mammals periods of resource abundance and scarcity are expressed on the scale of years not seasons (Jaksic et al 1993;Jones and Barmuta 1998). Table 5 Overall interspecific differences between diets of carnivores (C coyote, B bobcat, GF gray fox) in different study sites, during dry and wet seasons, detected by chi-square analyses of contingency tables, or by Fisher exact tests (FET) when the percent of expected values lower than 5 in the contingency tables was higher than 20%.…”

Section: Discussionsupporting

confidence: 77%

Competition and intraguild predation among three sympatric carnivores

et al. 2000

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We examined the relative roles of dominance in agonistic interactions and energetic constraints related to body size in determining local abundances of coyotes (Canis latrans, 8-20 kg), gray foxes (Urocyon cinereoargenteus, 3-5 kg) and bobcats (Felis rufus, 5-15 kg) at three study sites (hereafter referred to as NP, CP, and SP) in the Santa Monica Mountains of California. We hypothesized that the largest and behaviorally dominant species, the coyote, would exploit a wider range of resources (i.e., a higher number of habitat and/or food types) and, consequently, would occur in higher density than the other two carnivores. We evaluated our hypotheses by quantifying their diets, food overlap, habitat-specific abundances, as well as their overall relative abundance at the three study sites. We identified behavioral dominance of coyotes over foxes and bobcats in Santa Monica because 7 of 12 recorded gray fox deaths and 2 of 5 recorded bobcat deaths were due to coyote predation, and no coyotes died as a result of their interactions with bobcats or foxes. Coyotes and bobcats were present in a variety of habitats types (8 out of 9), including both open and brushy habitats, whereas gray foxes were chiefly restricted to brushy habitats. There was a negative relationship between the abundances of coyotes and gray foxes (P=0.020) across habitats, suggesting that foxes avoided habitats of high coyote predation risk. Coyote abundance was low in NP, high in CP, and intermediate in SP. Bobcat abundance changed little across study sites, and gray foxes were very abundant in NP, absent in CP, and scarce in SP; this suggests a negative relationship between coyote and fox abundances across study sites, as well. Bobcats were solely carnivorous, relying on small mammals (lagomorphs and rodents) throughout the year and at all three sites. Coyotes and gray foxes also relied on small mammals year-round at all sites, though they also ate significant amounts of fruit. Though there were strong overall interspecific differences in food habits of carnivores (P<0.0001), average seasonal food overlaps were high due to the importance of small mammals in all carnivore diets [bobcat-gray fox: 0.79±0.09 (SD), n=4; bobcat-coyote: 0.69±0.16, n=6; coyote-gray fox: 0.52±0.05, n=4]. As hypothesized, coyotes used more food types and more habitat types than did bobcats and gray foxes and, overall, coyotes were the most abundant of the three species and ranged more widely than did gray foxes. We propose that coyotes limit the number and distribution of gray foxes in Santa Monica Mountains, and that those two carnivores exemplified a case in which the relationship between their body size and local abundance is governed by competitive dominance of the largest species rather than by energetic equivalences. However, in the case of the intermediate-sized bobcat no such a pattern emerged, likely due to rarity or inconsistency of agonistic interactions and/or behavioral avoidance of encounters by subordinate species.

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Section: Discussionsupporting

confidence: 77%

Competition and intraguild predation among three sympatric carnivores

et al. 2000

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“…No obstante, no hay razones para suponer que las comunidades siempre tienen la misma estructura gremial (i.e., que la agremiación es un atributo invariable en tiempo y espacio). El estudio de la dinámica de la agremiación es especialmente relevante para entender cómo se estructuran las comunidades (e.g., McNaughton 1978, Cornell y Kahn 1989, Mac Nally 1994, pero también para comprender qué procesos están involucrados en su organización (e.g., Jaksic y Delibes 1987, Jaksic y Medel 1990, Jaksic et al 1993, Marti et al 1993; véase más abajo). Tabla 3.…”

Section: Aspectos Estructuralesunclassified

Diet switching of seed-eating birds wintering in grazed habitats of the central Monte Desert, Argentina

et al. 2017

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“…High overlap among these predators may only reflect a failure to identify exactly the prey species being used. This is not the case for the carnivorous guild, because barn and great horned owls preyed almost exclusively on vertebrates, mainly mammals, especially a single rodent species (Phyllotis darwini; see Jaksic et al 1993Jaksic et al , 1996. Therefore, there is no aliasing problem here, and the two owls may be said to be virtually redundant.…”

Section: Somewhat Harder Evidence For Redundancymentioning

confidence: 98%

How Much Functional Redundancy Is Out There, or, Are We Willing to Do Away with Potential Backup Species?

Jaksić¹

2003

How Landscapes Change

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A Long-Term Study on the Dynamics of Guild Structure among Predatory Vertebrates at a Semi-Arid Neotropical Site

Cited by 67 publications

References 30 publications

Competition and intraguild predation among three sympatric carnivores

Competition and intraguild predation among three sympatric carnivores

Diet switching of seed-eating birds wintering in grazed habitats of the central Monte Desert, Argentina

How Much Functional Redundancy Is Out There, or, Are We Willing to Do Away with Potential Backup Species?

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