Behavioral and physiological traits of ectotherms are especially sensitive to fluctuations of environmental temperature. In particular, niche-specialist lizards are dependent on their physiological plasticity to adjust to changing environmental conditions. Lizards of the genus Phymaturus are viviparous, mainly herbivorous, and inhabit only rock promontories in the steppe environments of Patagonia and the Andes. Herein, we examine the vulnerability of the southernmost Phymaturus species to global warming: the endemic Phymaturus calcogaster, which lives in a mesic environment in eastern Patagonia. We studied body temperatures in the field (Tb), preferred body temperatures in a thermogradient (Tpref), the operative (Te) and environmental temperatures, and the dependence of running performance on body temperature. P. calcogaster had a mean Tb (27.04°C) and a mean Te (31.15°C) both lower than their preferred temperature (Tpref = 36.61°C) and the optimal temperature for running performance (To = 37.13°C). Lizard activity seems to be restraint during the early afternoon due high environmental temperatures. However, both, the high safety margin and warming tolerance suggest that the expected increase in environmental temperatures due to global warming (IPCC report in 2018) would not threaten, but indeed enhance locomotor performance in this population. 相似文献
Phenotypic variation in organisms depends on the genotype and the environmental constraints of the habitat that they exploit. Therefore, for marine species inhabiting contrasting aquatic conditions, it is expected to find covariation between the shape and its spatial distribution. We studied the morphology of the head and cephalic sensory canals of the eelpout Austrolycus depressiceps (4.5–22.5 cm TL) across its latitudinal distribution in South Pacific (45°S–55°S). Geometric morphometric analyses show that the shape varied from individuals with larger snout and an extended suborbital canal to individuals with shorter snouts and frontally compressed suborbital canal. There was size variation across the sampled populations, but that size does not have a clear latitudinal gradient. Only 8% of the shape variation relates to this size variation (allometry), represented by a decrease in the relative size of the eye, and a depression of the posterior margin of the head. There were spatial differences in the shape of the head, but these differences were probably caused by allometric effects. Additionally, 2 of the canals of the cephalic lateralis pores and the head shape showed modularity in its development. This study shows that the morphology of marine fish with a shallow distribution varies across distances of hundreds of kilometers (i.e., phenotypic modulation). 相似文献
Landscape Ecology - Biodiversity is closely related to landscape heterogeneity, but both are difficult to evaluate directly. Apex predators, such as raptors, are potential surrogate indicators of... 相似文献
1. An experiment was conducted to determine the individual and combined effects of two essential oils, oregano and garlic, on carcass characteristics, meat composition, colour, pH and sensory quality of broiler meat.
2. The diets were supplemented with no essential oil (control), oregano essential oil or garlic essential oil at 300 mg/kg and oregano essential oil at 150 mg/kg + garlic essential oil at 150 mg/kg.
3. Dietary oregano and garlic oil supplementation did not affect carcass yields, the relative weight of carcass parts, breast and thigh meat composition, pH or b* value of breast meat. Oregano + garlic oil supplementation significantly decreased the L* value. The a* value of breast meat in birds given a diet supplemented with oregano oil was lower than that in birds given a diet supplemented with garlic oil and oregano oil + garlic oil. The essential oil addition had no positive effect on the oxidative stability. There was no difference between the treatments in breast appearance.
4. The juiciness, flavour, oxidised flavour and acceptability of breast meat samples were affected by treatments. 相似文献