Forest microclimates and climate change: Importance, drivers and future research agenda

Abstract

Forest microclimates contrast strongly with the climate outside forests. To fully understand and better predict how forests' biodiversity and functions relate to climate and climate change, microclimates need to be integrated into ecological research. Despite the potentially broad impact of microclimates on the response of forest ecosystems to global change, our understanding of how microclimates within and below tree canopies modulate biotic responses to global change at the species, community and ecosystem level is still limited. Here, we review how spatial and temporal variation in forest microclimates result from an interplay of forest features, local water balance, topography and landscape composition. We first stress and exemplify the importance of considering forest microclimates to understand variation in biodiversity and ecosystem functions across forest landscapes. Next, we explain how macroclimate warming (of the free atmosphere) can affect microclimates, and vice versa, via interactions with land‐use changes across different biomes. Finally, we perform a priority ranking of future research avenues at the interface of microclimate ecology and global change biology, with a specific focus on three key themes: (1) disentangling the abiotic and biotic drivers and feedbacks of forest microclimates; (2) global and regional mapping and predictions of forest microclimates; and (3) the impacts of microclimate on forest biodiversity and ecosystem functioning in the face of climate change. The availability of microclimatic data will significantly increase in the coming decades, characterizing climate variability at unprecedented spatial and temporal scales relevant to biological processes in forests. This will revolutionize our understanding of the dynamics, drivers and implications of forest microclimates on biodiversity and ecological functions, and the impacts of global changes. In order to support the sustainable use of forests and to secure their biodiversity and ecosystem services for future generations, microclimates cannot be ignored.

Thermal optima of gross primary productivity are closely aligned with mean air temperatures across Australian wooded ecosystems

“…Potential explanations for this include ecosystem‐scale light‐limitation caused by seasonal cloud‐cover in tropical ecosystems (Kanniah et al, 2010; Malhi et al, 2017), decreased light availability during winter (i.e. during lower Ta conditions) in southern latitudes (Hatzianastassiou et al, 2005) where temperate forests grow, and the effect of forest microclimates limiting light availability to lower canopy leaves (De Frenne et al, 2021). However, the lack of a relationship between Fsd and T opt (Figure SI10a) at the 90 th quantile suggests that light limitation does not drive the position of T opt on the GPP–Ta curve.…”

Climate Change Alters Temperate Forest Canopies and Indirectly Reshapes Arthropod Communities

“…Canopy microclimates diverge largely from those of the understory. The shape and range of the vertical air temperature profile of temperate canopies depend on several variables including season, time of the day, canopy architecture, and tree species (De Frenne et al, 2021). This gradient contributes to the vertical distribution of arthropod species in the canopy, according to the physiological-efficiency hypothesis (i.e., arthropod distribution reflects their physiological tolerance to abiotic and biotic conditions, Wardhaugh, 2014).…”

MIRRA: A Modular and Cost-Effective Microclimate Monitoring System for Real-Time Remote Applications

“…While most experimental designs require air and soil temperature, and relative air humidity logging, additional sensors are sometimes employed to measure specific variables. Examples are wind direction and speed, precipitation, soil moisture content and light intensity [ 3 ]. To optimise flexibility, MIRRA has multiple digital and analogue sensor ports, including three I 2 C (Inter-Integrated Circuit), two SPI (Serial Peripheral Interface), two one-wire and two analogue ports.…”

“…Climate change is having profound impacts on ecological, agricultural and other societal systems [ 1 , 2 , 3 ]. Quantifying climate change and its consequences has become a major focus of the physical and life sciences.…”

“…Quantifying climate change and its consequences has become a major focus of the physical and life sciences. Our knowledge of the ongoing changes in the climate system, however, predominantly relies on a global network of official weather stations [ 3 , 4 , 5 ]. Generally, sensors are established according to the guidelines of the World Meteorological Organisation.…”