(ISI Web of Science 22-01-2007)
AU CARRASCAL, LM
LOPEZ, P
MARTIN, J
SALVADOR, A
TI BASKING AND
ANTIPREDATOR BEHAVIOR IN A HIGH-ALTITUDE LIZARD - IMPLICATIONS OF HEAT-EXCHANGE
RATE
SO ETHOLOGY (1992) 92:143-154
AB This paper presents
an observational and experimental study of the basking behaviour and heat
exchange rate of the montane lizard Lacerta monticola. The results obtained by
these procedures were coupled in order to understand behavioural mechanims
promoting effective thermoregulation at high altitudes. Heating rate was higher
when body size was smaller, and substrate temperature and sun rays incidence
angle were higher. The lizards cooled faster when body size and substrate
temperature were lower, and when the body temperature of the lizard going into
shadow was higher. Time exposed to sun and mean duration of basking periods
were longer early in the morning, while bask frequency increased through the
morning. Our results suggest that time devoted to basking is mainly obtained by
regulating bask duration. Lizards obtained the necessary time for heating by
means of long basking periods. Mean travel distance per minute and distance to
the nearest refuge increased from early morning to midday. These behavioural
variables were tightly correlated with the expected heating rate of
individuals. Body size affects thermoregulatory behaviour as well as locomotor
activity. Juvenile lizards, with small body mass and high surface-to-volume
ratios, were subjected to faster heating and cooling rates, basked more
frequently than adults (but during shorter periods), and devoted more time to
locomotion than adults. The thermoregulatory behaviour of L. monticola is the
result of the combination of shuttling heliothermy by basking and the
exploitation of thermal opportunities offered by patches in shade through
thermal exchange with the substrate.
TC 52 citas
AU MORENO, E
CARRASCAL, LM
TI LEG MORPHOLOGY AND
FEEDING POSTURES IN 4 PARUS-SPECIES - AN EXPERIMENTAL ECOMORPHOLOGICAL APPROACH
SO ECOLOGY (1993)
74:2037-2044
AB The foraging behavior
of four Parus species feeding at artificial feeders was studied, while
controlling for ecological variables related to patch characteristics (food
quality, food access, and escape distance to the nearest refuge). Hindlimb
morphology (osteology and myology) was analyzed and compared with foraging
postures at feeders. Using the Long-Tailed Tit as an appropriate outgroup for
comparison, and considering functional changes associated with morphological
changes, we demonstrated the existence of clear ecomorphological patterns
relating foraging postures and hindlimb morphology in the four Parus species
studied. The Blue Tit uses hanging postures preferably and its hindlimb
morphology is modified for helping leg flexion. The Crested Tit more often
stands and its hindlimb morphology is modified to aid leg extension. Great and
Coal Tits are ecologically and morphologically intermediate between the two
former species. Our results show morphology as a determinant of locomotion
mode. Since foraging postures are tightly associated with substrate use, then
morphology should be considered when studying pressures determining community
organization. Our proposed integrative method for dealing with ecomorphology
can be valuable in demonstrating the adaptiveness of morphological structures
in phylogenetically and ecologically related species.
TC 32 citas
AU DIAZ, JA
CARRASCAL, LM
TI REGIONAL
DISTRIBUTION OF A MEDITERRANEAN LIZARD - INFLUENCE OF HABITAT CUES AND PREY
ABUNDANCE
SO JOURNAL OF
BIOGEOGRAPHY (1991) 18:291-297
AB We studied the
distribution of a common Mediterranean lacertid lizard, Psammodromus algirus
(L.) 1758, on nineteen sites within a regional gradient of homogeneous yet
contrasted habitats. This scale was large enough to allow line-transect
estimates of lizard abundance, which were related to quantitative (and when
possible multivariate) measurements of the structure and floristic composition
of vegetation, the abundance of arthropod prey, the relative density of other
lizard species, and the climatic data obtained from nearby meteorological
stations. Neither the climate not the abundance of other lizards seemed to
condition the quantitative distribution of the species. The positive influence
of broad-leaved forests on the abundance of P. algirus appeared to be a
consequence of structure attributes more directly related to the ecology of
lizards than floristic composition per se. Thus, population levels were most
highly correlated with the cover of shrubs over 20 cm in height, and once this
structural requirement was met, they increased with the abundance of potential
prey (itself conditioned by vegetation cover at the ground level and litter
cover). We suggest that our results should be interpreted in the context of
thermoregulatory, predator avoidance and movement minimization strategies whose
influence on survival, and hence abundance, could probably be applied to other
insectivorous lizards from temperate zones.
TC 29 citas
AU CARRASCAL, LM
MORENO, E
TELLERIA, JL
TI ECOMORPHOLOGICAL
RELATIONSHIPS IN A GROUP OF INSECTIVOROUS BIRDS OF TEMPERATE FORESTS IN WINTER
SO HOLARCTIC ECOLOGY
(1990) 13:105-111
AB We examined the relationships between morphology and foraging behaviour in a group of insectivorous birds wintering in temperate mixed forests in northern Iberia. Using principal components analysis we reduced 11 biometric variables to three major morphological components and 20 foraging categories to four major ecological factors. The relative length of the tarsometatarsus and bill morphology were the most important morphological variables predicting foraging ecology. Birds exploiting distal parts of trees and foliage were generally smaller and had relatively longer tarsometatarsi than those foraging on trunks. Foraging on the ground and branches of medium diameter was associated with bill thickness. Ecomorphological patterns were discernable at the level of substrate use and foraging methods, but bear no relation to selection of tree species or foraging height. Morphology correctly predicted niche breadth and interspecific overlap. In Parus spp. interspecific differences in bill shape could explain 63% of the interspecific segregation according to substrate use.
TC 27 citas
AU CARRASCAL, LM
TELLERIA, JL
TI BIRD SIZE AND
DENSITY - A REGIONAL APPROACH
SO AMERICAN NATURALIST (1991) 138:777-784.
AB This paper investigateS the
relationship between weight (W) and density (d) in small
insectivorous birds of the Basque Country (North of Spain). Ecological
densities (di) were estimated using line transects in the 10 most
extensive habitats of the region (47 species weighing between 6 g -Regulus
ignicapillus- and
TC 15 citas