Hotter Temperatures Reduce the Diversity and Alter the Composition of Woody Plants in an Amazonian Forest.

Rapid warming and high temperatures are an immediate threat to global ecosystems, but the threat may be especially pronounced in the tropics. Although low-latitude tree species are widely predicted to be vulnerable to warming, information about how tropical tree diversity and community composition respond to elevated temperatures remains sparse. Here, we study long-term responses of tree diversity and composition to increased soil and air temperatures at the Boiling River-an exceptional and unique "natural warming experiment" in the central Peruvian Amazon.

Leaf thermal safety margins decline at hotter temperatures in a natural warming 'experiment' in the Amazon.

The threat of rising global temperatures may be especially pronounced for low-latitude, lowland plant species that have evolved under stable climatic conditions. However, little is known about how these species may acclimate to elevated temperatures. Here, we leveraged a strong, steep thermal gradient along a natural geothermal river to assess the ability of woody plants in the Amazon to acclimate to elevated air temperatures.

Tropical Trees Will Need to Acclimate to Rising Temperatures-But Can They?

For tropical forests to survive anthropogenic global warming, trees will need to avoid rising temperatures through range shifts and "species migrations" or tolerate the newly emerging conditions through adaptation and/or acclimation. In this literature review, we synthesize the available knowledge to show that although many tropical tree species are shifting their distributions to higher, cooler elevations, the rates of these migrations are too slow to offset ongoing changes in temperatures, especially in lowland tropical rainforests where thermal gradients are shallow or nonexistent. We also show that the rapidity and severity of global warming make it unlikely that tropical tree species can adapt (with some possible exceptions).

Thermal optimum of photosynthesis is controlled by stomatal conductance and does not acclimate across an urban thermal gradient in six subtropical tree species.

Modelling the response of plants to climate change is limited by our incomplete understanding of the component processes of photosynthesis and their temperature responses within and among species. For ≥20 individuals, each of six common subtropical tree species occurring across steep urban thermal gradients in Miami, Florida, USA, we determined rates of net photosynthesis (A ), maximum RuBP carboxylation, maximum RuBP regeneration and stomatal conductance, and modelled the optimum temperature (T ) and process rate of each parameter to address two questions: (1) Do the T of A (T ) and the maximum A (A ) of subtropical trees reflect acclimation to elevated growth temperatures? And (2) What limits A in subtropical trees? Against expectations, we did not find significant acclimation of T , A  or the T of any of the underlying photosynthetic parameters to growth temperature in any of the focal species. Model selection for the single best predictor of A both across leaf temperatures and at T revealed that the A of most trees was best predicted by stomatal conductance.

Getting lost with dementia: Encounters with the time-space of not knowing.

In this paper we explore the experience and implications of getting lost with dementia. While getting lost has become culturally emblematic of dementia, speaking as it does to a widespread fear of losing our place in the world, it is marked by an overall absence of critical attention. We argue that this critical hesitancy is part of a broader unease with 'dementing' that reveals a paradox in dementia scholarship as growing emphasis on strengths-based and capacity-oriented approaches to the condition shift attention away from episodes of disorientation, forgetting and unknowing that commonly arise after onset.