• Energy Research

Brief introduction: What are microclimates and why are they important?Microclimate science has developed into a global discipline. Microclimate science is increasingly used to understand and mitigate climate and biodiversity shifts. Here, we provide an overview of the current status of microclimate ecology and biogeography in terrestrial ecosystems, and where this field is heading next.Microclimate investigations in ecology and biogeography: We highlight the latest research on interactions between microclimates and organisms, including how microclimates influence individuals, and through them populations, communities and entire ecosystems and their processes. We also briefly discuss recent research on how organisms shape microclimates from the tropics to the poles.Microclimate applications in ecosystem management: Microclimates are also important in ecosystem management under climate change. We showcase new research in microclimate management with examples from biodiversity conservation, forestry and urban ecology. We discuss the importance of microrefugia in conservation and how to promote microclimate heterogeneity.Methods for microclimate science: We showcase the recent advances in data acquisition, such as novel field sensors and remote sensing methods. We discuss microclimate modelling, mapping and data processing, including accessibility of modelling tools, advantages of mechanistic and statistical modelling and solutions for computational challenges that have pushed the state-of-the-art of the field.What's next?We identify major knowledge gaps that need to be filled for further advancing microclimate investigations, applications and methods. These gaps include spatiotemporal scaling of microclimate data, mismatches between macroclimate and microclimate in predicting responses of organisms to climate change, and the need for more evidence on the outcomes of microclimate management.

Brief introduction: What are microclimates and why are they important?Microclimate science has developed into a global discipline. Microclimate science is increasingly used to understand and mitigate climate and biodiversity shifts. Here, we provide an overview of the current status of microclimate ecology and biogeography in terrestrial ecosystems, and where this field is heading next.Microclimate investigations in ecology and biogeography: We highlight the latest research on interactions between microclimates and organisms, including how microclimates influence individuals, and through them populations, communities and entire ecosystems and their processes. We also briefly discuss recent research on how organisms shape microclimates from the tropics to the poles.Microclimate applications in ecosystem management: Microclimates are also important in ecosystem management under climate change. We showcase new research in microclimate management with examples from biodiversity conservation, forestry and urban ecology. We discuss the importance of microrefugia in conservation and how to promote microclimate heterogeneity.Methods for microclimate science: We showcase the recent advances in data acquisition, such as novel field sensors and remote sensing methods. We discuss microclimate modelling, mapping and data processing, including accessibility of modelling tools, advantages of mechanistic and statistical modelling and solutions for computational challenges that have pushed the state-of-the-art of the field.What's next?We identify major knowledge gaps that need to be filled for further advancing microclimate investigations, applications and methods. These gaps include spatiotemporal scaling of microclimate data, mismatches between macroclimate and microclimate in predicting responses of organisms to climate change, and the need for more evidence on the outcomes of microclimate management.

Mosses often dominate the submerged vegetation in Arctic lakes and ponds, making them essential contributors to the primary production in these habitats. However, little is known about the factors controlling annual growth of Arctic mosses and their sensitivity to climatic changes. It has been suggested that nutrient translocation occurs in mosses, and that annual growth of mosses therefore depends strongly on weather conditions and less on local environmental conditions. In this study, we examined annual growth of Drepanocladus trifarius ((F. Weber and D. Mohr) Broth.) from two ponds in West Greenland in relation to weather conditions. A reconstruction of annual growth increments from 2009 to 2014 was made in 200 individual mosses, and biomass and length were related to different weather parameters. In addition, we examined whether there would be an indication of nutrient translocation across annual growth segments. We found a positive relationship between mean summer temperature and growth segment length, which indicates the importance of temperature during seasons with sufficient light levels for growth of the D. trifarius. Weather parameters associated with light conditions had no significant effect on growth, which probably reflect that D. trifarius in two shallow ponds were not light limited. The nutrient stoichiometry showed that phosphorus (P) contents in the tissue were low (0.04–0.11% DW), and nutrient resorption efficiencies of P amounted to 11–29%. This suggests that D. trifarius was P limited during its growth season, but appears capable of nutrient translocation across annual segments, possibly to maintain growth in oligotrophic environments. Despite low nitrogen (N) contents (0.94–2.09%), no resorption of N was found, which indicates that D. trifarius was not N-limited in order to sustain growth. In conclusion, this study shows that growth of D. trifarius in small high Arctic ponds are mainly controlled by summer temperatures.

Mosses often dominate the submerged vegetation in Arctic lakes and ponds, making them essential contributors to the primary production in these habitats. However, little is known about the factors controlling annual growth of Arctic mosses and their sensitivity to climatic changes. It has been suggested that nutrient translocation occurs in mosses, and that annual growth of mosses therefore depends strongly on weather conditions and less on local environmental conditions. In this study, we examined annual growth of Drepanocladus trifarius ((F. Weber and D. Mohr) Broth.) from two ponds in West Greenland in relation to weather conditions. A reconstruction of annual growth increments from 2009 to 2014 was made in 200 individual mosses, and biomass and length were related to different weather parameters. In addition, we examined whether there would be an indication of nutrient translocation across annual growth segments. We found a positive relationship between mean summer temperature and growth segment length, which indicates the importance of temperature during seasons with sufficient light levels for growth of the D. trifarius. Weather parameters associated with light conditions had no significant effect on growth, which probably reflect that D. trifarius in two shallow ponds were not light limited. The nutrient stoichiometry showed that phosphorus (P) contents in the tissue were low (0.04–0.11% DW), and nutrient resorption efficiencies of P amounted to 11–29%. This suggests that D. trifarius was P limited during its growth season, but appears capable of nutrient translocation across annual segments, possibly to maintain growth in oligotrophic environments. Despite low nitrogen (N) contents (0.94–2.09%), no resorption of N was found, which indicates that D. trifarius was not N-limited in order to sustain growth. In conclusion, this study shows that growth of D. trifarius in small high Arctic ponds are mainly controlled by summer temperatures.

AbstractClimate is assumed to strongly influence species distribution and abundance. Although the performance of many organisms is influenced by the climate in their immediate proximity, the climate data used to model their distributions often have a coarse spatial resolution. This is problematic because the local climate experienced by individuals might deviate substantially from the regional average. This problem is likely to be particularly important for sessile organisms like plants and in environments where small‐scale variation in climate is large. To quantify the effect of local temperature on vital rates and population growth rates, we used temperature values measured at the local scale (in situ logger measures) and integral projection models with demographic data from 37 populations of the forest herb Lathyrus vernus across a wide latitudinal gradient in Sweden. To assess how the spatial resolution of temperature data influences assessments of climate effects, we compared effects from models using local data with models using regionally aggregated temperature data at several spatial resolutions (≥1 km). Using local temperature data, we found that spring frost reduced the asymptotic population growth rate in the first of two annual transitions and influenced survival in both transitions. Only one of the four regional estimates showed a similar negative effect of spring frost on population growth rate. Our results for a perennial forest herb show that analyses using regionally aggregated data often fail to identify the effects of climate on population dynamics. This emphasizes the importance of using organism‐relevant estimates of climate when examining effects on individual performance and population dynamics, as well as when modeling species distributions. For sessile organisms that experience the environment over small spatial scales, this will require climate data at high spatial resolutions.

AbstractClimate is assumed to strongly influence species distribution and abundance. Although the performance of many organisms is influenced by the climate in their immediate proximity, the climate data used to model their distributions often have a coarse spatial resolution. This is problematic because the local climate experienced by individuals might deviate substantially from the regional average. This problem is likely to be particularly important for sessile organisms like plants and in environments where small‐scale variation in climate is large. To quantify the effect of local temperature on vital rates and population growth rates, we used temperature values measured at the local scale (in situ logger measures) and integral projection models with demographic data from 37 populations of the forest herb Lathyrus vernus across a wide latitudinal gradient in Sweden. To assess how the spatial resolution of temperature data influences assessments of climate effects, we compared effects from models using local data with models using regionally aggregated temperature data at several spatial resolutions (≥1 km). Using local temperature data, we found that spring frost reduced the asymptotic population growth rate in the first of two annual transitions and influenced survival in both transitions. Only one of the four regional estimates showed a similar negative effect of spring frost on population growth rate. Our results for a perennial forest herb show that analyses using regionally aggregated data often fail to identify the effects of climate on population dynamics. This emphasizes the importance of using organism‐relevant estimates of climate when examining effects on individual performance and population dynamics, as well as when modeling species distributions. For sessile organisms that experience the environment over small spatial scales, this will require climate data at high spatial resolutions.

Forest canopies buffer macroclimatic temperature fluctuations. However, we do not know if and how the capacity of canopies to buffer understorey temperature will change with accelerating climate change. Here we map the difference (offset) between temperatures inside and outside forests in the recent past and project these into the future in boreal, temperate and tropical forests. Using linear mixed-effect models, we combined a global database of 714 paired time series of temperatures (mean, minimum and maximum) measured inside forests vs. in nearby open habitats with maps of macroclimate, topography and forest cover to hindcast past (1970-2000) and to project future (2060-2080) temperature differences between free-air temperatures and sub-canopy microclimates. For all tested future climate scenarios, we project that the difference between maximum temperatures inside and outside forests across the globe will increase (i.e. result in stronger cooling in forests), on average during 2060-2080, by 0.27 ± 0.16 °C (RCP2.6) and 0.60 ± 0.14 °C (RCP8.5) due to macroclimate changes. This suggests that extremely hot temperatures under forest canopies will, on average, warm less than outside forests as macroclimate warms. This knowledge is of utmost importance as it suggests that forest microclimates will warm at a slower rate than non-forested areas, assuming that forest cover is maintained. Species adapted to colder growing conditions may thus find shelter and survive longer than anticipated at a given forest site. This highlights the potential role of forests as a whole as microrefugia for biodiversity under future climate change.