Lack of thermal acclimation in multiple indices of climate vulnerability in bumblebees.

Indices of climate vulnerability are used to predict species' vulnerability to climate change based on intrinsic physiological traits, such as thermal tolerance, thermal sensitivity and thermal acclimation, but rarely is the consistency among indices evaluated simultaneously. We compared the thermal physiology of queen bumblebees between a species experiencing local declines () and a species exhibiting continent-wide increases (). We conducted a multi-week acclimation experiment under simulated climate warming to measure critical thermal maximum (CT), critical thermal minimum (CT), the thermal sensitivity of metabolic rate and water loss rate and acclimation in each of these traits.

The effects of humidity on thermoregulatory physiology of a small songbird.

Scholander-Irving curves describe the relationship between ambient temperature and metabolic rate and are fundamental to understanding the energetic demands of homeothermy. However, Scholander-Irving curves are typically measured in dry air, which is not representative of the humidity many organisms experience in nature. Consequently, it is unclear (1) whether Scholander-Irving curves (especially below thermoneutrality) are altered by humidity, given the effects of humidity on thermal properties of air, and (2) whether physiological responses associated with Scholander-Irving curves in the lab reflect organismal performance in humid field conditions.

Amphibians Exhibit Extremely High Hydric Costs of Respiration.

Terrestrial environments pose many challenges to organisms, but perhaps one of the greatest is the need to breathe while maintaining water balance. Breathing air requires thin, moist respiratory surfaces, and thus the conditions necessary for gas exchange are also responsible for high rates of water loss that lead to desiccation. Across the diversity of terrestrial life, water loss acts as a universal cost of gas exchange and thus imposes limits on respiration.

Water and sediment chemistry drivers of chlorophyll-a dynamics within a Ramsar declared floodplain pan wetland system.

Floodplain pans are hydrologically dynamic in nature and characterised by variables such as chlorophyll-a (chl-a), water, and sediment chemistry over their hydroperiods. The present study investigated the spatio-temporal variations in water and sediment physico-chemical, and chlorophyll-a concentration characteristics of six floodplain pans found in the Ramsar declared Makuleke wetlands, Kruger National Park, South Africa. The water and sediment physico-chemical variable values were generally elevated during the high-water period, whereas chlorophyll-a concentrations varied across pans and hydroperiod.