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Microhabitat Segregation (microhabitat + segregation)

Distribution by Scientific Domains
Life Sciences75%

Selected Abstracts

Age-Related Microhabitat Segregation in Willow Tit Parus montanus Winter Flocks

ETHOLOGY, Issue 11 2000
Lluís Brotons
It is expected that through flexibility in behaviour, flock living birds respond to the asymmetries in resource access derived from dominance relationships. We analysed the microhabitat use of willow tits in winter flocks and assessed possible factors which shape habitat segregation between adults and juveniles in different temperature regimes. When foraging in mild conditions (ambient temperature >,0°C), flocks split up into subgroups with adults foraging in inner parts of trees more often than juveniles. However, no differences were recorded in the vertical position occupied in trees. In harsh conditions (< , 4°C), flocks re-united and juveniles further moved to outer parts of trees, increasing horizontal segregation between age classes. In mild conditions, vigilance behaviour was not related to the position of birds in trees, but in harsh conditions, scanning frequency was higher in outer parts of trees only for adults. In mild weather, juvenile position in trees was associated with body size and mass. The foraging microhabitat segregation detected in harsh conditions fits the age-related hoarding distribution previously described in the same population. This supports the hypothesis that hoarded food is important in determining future foraging habitat use. Adult preference and intraspecific competition for safer or richer inner parts of trees as foraging sites during harsh conditions seems to determine the habitat segregation between adults and juveniles. Furthermore, we suggest that in mild weather, when foraging in the absence of adults, juveniles balance the costs of using a potentially dangerous microhabitat with the benefits of building energetically cheap and large food reserves through hoarding. The expected patterns of microhabitat segregation may differ in parids, depending on whether predation risk or other factors such as food availability are the main factors controlling habitat quality. [source]

Interdemic variation of cannibalism in a wolf spider (Pardosa monticola) inhabiting different habitat types

ECOLOGICAL ENTOMOLOGY, Issue 2 2006
Jeroen Vanden Borre
Abstract., 1.,Cannibalism was investigated in the wolf spider Pardosa monticola (Clerck) using spiders collected from four populations with varying densities, inhabiting two different coastal dune habitat types. Sampled individuals were paired randomly and tested immediately for their cannibalism propensity. 2.,The occurrence of cannibalism was found to be influenced by the size (cephalothorax width) of both the smaller and the larger spider of a pair. Larger size differences enhanced cannibalism. 3.,Cannibalism rates were not significantly different in spiders from high-density compared with low-density populations. Cannibalism rates showed, however, large variability between habitat types, with higher rates in spiders from dune grasslands than from dune slacks. This is suggested to result from differences in prey availability throughout the growing season between both habitat types. 4.,Different size classes of spiders did not use different microhabitats, indicating that microhabitat segregation as a cannibalism-avoidance behaviour is absent in this species. [source]

Age-Related Microhabitat Segregation in Willow Tit Parus montanus Winter Flocks

ETHOLOGY, Issue 11 2000
Lluís Brotons
It is expected that through flexibility in behaviour, flock living birds respond to the asymmetries in resource access derived from dominance relationships. We analysed the microhabitat use of willow tits in winter flocks and assessed possible factors which shape habitat segregation between adults and juveniles in different temperature regimes. When foraging in mild conditions (ambient temperature >,0°C), flocks split up into subgroups with adults foraging in inner parts of trees more often than juveniles. However, no differences were recorded in the vertical position occupied in trees. In harsh conditions (< , 4°C), flocks re-united and juveniles further moved to outer parts of trees, increasing horizontal segregation between age classes. In mild conditions, vigilance behaviour was not related to the position of birds in trees, but in harsh conditions, scanning frequency was higher in outer parts of trees only for adults. In mild weather, juvenile position in trees was associated with body size and mass. The foraging microhabitat segregation detected in harsh conditions fits the age-related hoarding distribution previously described in the same population. This supports the hypothesis that hoarded food is important in determining future foraging habitat use. Adult preference and intraspecific competition for safer or richer inner parts of trees as foraging sites during harsh conditions seems to determine the habitat segregation between adults and juveniles. Furthermore, we suggest that in mild weather, when foraging in the absence of adults, juveniles balance the costs of using a potentially dangerous microhabitat with the benefits of building energetically cheap and large food reserves through hoarding. The expected patterns of microhabitat segregation may differ in parids, depending on whether predation risk or other factors such as food availability are the main factors controlling habitat quality. [source]

Morphological differences between two ecologically similar sympatric fishes

JOURNAL OF FISH BIOLOGY, Issue 10 2009
I. P. Helland
Morphological differentiation and microhabitat segregation of two ecologically similar populations of pelagic planktivorous fishes, Coregonus albula and the smaller Coregonus fontanae, were studied in Lake Stechlin (northern Germany). Both populations performed diel vertical migrations, although C. fontanae was always situated in deeper pelagic water than C. albula both during day and night. Landmark-based geometric morphometrics revealed that sympatric C. albula and C. fontanae differ in external morphology, with main differences found in head length and eye position, as well as in length and width of the caudal peduncle. Moreover, while C. albula has a similar morphology over all sizes, the shape of C. fontanae changes with size. Accordingly, the morphology of the two is most different at smaller size. Although the morphological differences may reflect adaptations to the slightly differing microhabitats of the two populations, there is no conclusive evidence that this correspondence between ecology and morphology is the main mechanism behind the coexistence of the closely related coregonids in Lake Stechlin. [source]