Food-niche Differences Between Two Syntopic Scops-Owls on Okinawa Island, Japan

Food niches of Common Barn-Owl (Tyto alba) populations were studied for 8 years in Utah and Idaho. Small mammals dominated the diet as they do in most parts of the barn-owl's range. Mean prey weight was nearly identical between the two owl populations. Food-niche breadth, though, was significantly broader in Idaho than in Utah. Food-niche breadth was also more variable in Idaho than in Utah both within and between years. Voles (Microtus spp.) were predominant prey for both owl populations and were the only prey whose numeric variation in the diet significantly affected mean prey weight and food-niche breadth. Vegetative composition was less varied and more uniformly favorable to voles in Utah. The Idaho area contained a smaller poportion of good vole habitat but had a greater diversity of vegetation including deserts suitable for small mammal species not found in the Utah study area. These vegetative differences and their effects on small mammal species diversity and density were the most apparent causes of food-niche differences between the two owl populations.

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Niche differences between two sympatric whiptail lizards (Cnemidophorus abaetensis and C. ocellifer, Teiidae) in the restinga habitat of northeastern Brazil

Brazilian Journal of Biology ◽

10.1590/s1519-69842007000100006 ◽

2007 ◽

Vol 67 (1) ◽

pp. 41-46 ◽

Cited By ~ 14

Author(s):

EJR. Dias ◽

CFD. Rocha

Keyword(s):

Niche Differentiation ◽

Sympatric Species ◽

Northeastern Brazil ◽

Activity Period ◽

Microhabitat Use ◽

Lizard Species ◽

Niche Differences ◽

Niche Dimension ◽

Food Niche ◽

Prey Items

Differences among sympatric lizard species usually result from differences in the use of three resources: space, time and food or some combination of these three. However, differences in resource utilization among sympatric species may simply reflect their specific ecological needs rather than competitive pressures. In this study, we analyzed the temporal, spatial and food niche of two congeneric teiids (Cnemidophorus abaetensis and C. ocellifer) living sympatrically in the "restinga" habitat of Abaeté in the Salvador Municipality, Bahia State, Brazil to assess the degree of niche differentiation among them. The whiptail species overlapped considerably in an hourly activity (Ojk = 0.93), in microhabitat use (Ojk = 0.97) and in the prey items consumed (Ojk = 0.89). Differences in amount of vegetation in the microhabitats used by both lizard species may have contributed to differences in the activity period and in the distribution of the main prey eaten by these lizards which may, in turn, facilitate their coexistence in Abaeté. Although sympatric C. ocellifer and C. abaetensis in Abaeté differed only slightly in their use of microhabitats, period of activity and diet, the most important niche dimension segregating the two species seemed to be the food niche.

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Comparative diets of sympatric nesting raptors in the eastern deciduous forest biome

Canadian Journal of Zoology ◽

10.1139/z92-140 ◽

1992 ◽

Vol 70 (5) ◽

pp. 984-992 ◽

Cited By ~ 19

Author(s):

Thomas Bosakowski ◽

Dwight G. Smith

Keyword(s):

New York ◽

Deciduous Forest ◽

Niche Overlap ◽

Eastern Deciduous Forest ◽

Nest Sites ◽

Niche Differences ◽

Species Packing ◽

Niche Metrics ◽

Food Niche ◽

Forest Biome

Diets and food-niche metrics of nesting raptors were studied in the eastern deciduous forest biome of northern New Jersey, southeastern New York, and northwestern Connecticut. Raptor diets were determined from 2506 prey individuals recovered from prey remains and pellets collected from nest sites of a community consisting of five hawk and four owl species. Food-niche overlaps were higher on average in the hawk guild (0.422) than in the owl guild (0.342), correlating with increased species packing and decreased body size differences in the hawk guild. Differences in activity times (diurnal versus nocturnal) did not result in reduced food-niche overlap between diurnal and nocturnal raptors. The lack of interference-type competition probably allowed greater exploitative-type competition but was offset by nearly exclusive use of certain prey types by several raptor species. Thus, temporal niche differences ultimately did aid in the resource partitioning of food between hawks and owls. Overall, the forest raptor community displayed significant food-niche overdispersion, with 35 of 36 food-niche overlap values below the 0.6 "competition" threshold. This result would be expected in a community structured by competition.

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Dispersal syndromes are poorly associated with climatic niche differences in the Azorean seed plants

Journal of Biogeography ◽

10.1111/jbi.14151 ◽

2021 ◽

Author(s):

María Leo ◽

Manuel J. Steinbauer ◽

Paulo A.V. Borges ◽

Eduardo B. Azevedo ◽

Rosalina Gabriel ◽

...

Keyword(s):

Seed Plants ◽

Climatic Niche ◽

Dispersal Syndromes ◽

Niche Differences

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Supplementary descriptions of Pergalumna amamiensis Aoki, 1984 (Acariformes, Galumnoidea) from Ryukyu Islands

Zootaxa ◽

10.11646/zootaxa.4647.1.24 ◽

2019 ◽

Vol 4647 (1) ◽

pp. 378-384

Author(s):

WATARU HAGINO ◽

SATOSHI SHIMANO

Keyword(s):

Body Length ◽

Morphological Traits ◽

Granular Structure ◽

Surface Pattern ◽

Ryukyu Islands ◽

Body Width ◽

Okinawa Island ◽

Ishigaki Island ◽

Circular Surface ◽

Median Pore

A species of oribatid mites, Pergalumna amamiensis was collected from Amami-Ohshima Island, Ishigaki Island, and Okinawa Island, Southwestern Japan. The specimens were studied in detail, and supplementary descriptions are provided; these include features of the rostrum, the subcapitulum and the surface pattern of pteromorphs. The main morphological traits for this species are summarized as follows; body length 519–570 μm, body width 363–410 μm, rostral tip pointed, sensillus with a long stalk covered by minute barbs, porose areas Aa bulbous, porose areas A1, A2, and A3 circular, surface of pteromorphs ornamented by fine granular structure and dense wrinkles, fine granular structure on prodorsum, subcapitulum, genital plates and anal plates, median pore on the notogaster represented as single pore.

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