Macroclimate warming is often assumed to occur within forests despite the potential for tree cover to modify microclimates. Here, using paired measurements, we compared the temperatures under the ...canopy versus in the open at 98 sites across 5 continents. We show that forests function as a thermal insulator, cooling the understory when ambient temperatures are hot and warming the understory when ambient temperatures are cold. The understory versus open temperature offset is magnified as temperatures become more extreme and is of greater magnitude than the warming of land temperatures over the past century. Tree canopies may thus reduce the severity of warming impacts on forest biodiversity and functioning.
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.
Below‐canopy forest microclimates contrast strongly with the climate outside forests due to the presence of trees and shrubs. Here we review the drivers and the importance of forest microclimates in the face of climate change, and perform a priority ranking of future research avenues.
The role of climate in determining range margins is often studied using species distribution models (SDMs), which are easily applied but have well‐known limitations, e.g. due to their correlative ...nature and colonization and extinction time lags. Transplant experiments can give more direct information on environmental effects, but often cover small spatial and temporal scales. We simultaneously applied a SDM using high‐resolution spatial predictors and an integral projection (demographic) model based on a transplant experiment at 58 sites to examine the effects of microclimate, light and soil conditions on the distribution and performance of a forest herb, Lathyrus vernus, at its cold range margin in central Sweden. In the SDM, occurrences were strongly associated with warmer climates. In contrast, only weak effects of climate were detected in the transplant experiment, whereas effects of soil conditions and light dominated. The higher contribution of climate in the SDM is likely a result from its correlation with soil quality, forest type and potentially historic land use, which were unaccounted for in the model. Predicted habitat suitability and population growth rate, yielded by the two approaches, were not correlated across the transplant sites. We argue that the ranking of site habitat suitability is probably more reliable in the transplant experiment than in the SDM because predictors in the former better describe understory conditions, but that ranking might vary among years, e.g. due to differences in climate. Our results suggest that L. vernus is limited by soil and light rather than directly by climate at its northern range edge, where conifers dominate forests and create suboptimal conditions of soil and canopy‐penetrating light. A general implication of our study is that to better understand how climate change influences range dynamics, we should not only strive to improve existing approaches but also to use multiple approaches in concert.
Farmers’ practices in the management of agricultural landscapes influence biodiversity with implications for livelihoods, ecosystem service provision, and biodiversity conservation. In this study, we ...examined how smallholding farmers in an agriculture-forest mosaic landscape in southwestern Ethiopia manage trees and forests with regard to a few selected ecosystem services and disservices that they highlighted as “beneficial” or “problematic.” Qualitative and quantitative data were collected from six villages, located both near and far from forest, using participatory field mapping and semistructured interviews, tree species inventory, focus group discussions, and observation. The study showed that farmers’ management practices, i.e., the planting of trees on field boundaries amid their removal from inside arable fields, preservation of trees in semimanaged forest coffee, maintenance of patches of shade coffee fields in the agricultural landscape, and establishment of woodlots with exotic trees result in a restructuring of the forest-agriculture mosaic. In addition, the strategies farmers employed to mitigate crop damage by wild mammals such as baboons and bush pigs, e.g., migration and allocation of migrants on lands along forests, have contributed to a reduction in forest and tree cover in the agricultural landscape. Because farmers’ management practices were overall geared toward mitigating the negative impact of disservices and to augment positive services, we conclude that it is important to operationalize ecosystem processes as both services and disservices in studies related to agricultural landscapes.
Summary
Functional traits mechanistically capture plant responses to environmental gradients as well as plant effects on ecosystem functioning. Yet most trait‐based theory stems from terrestrial ...systems and extension to other habitats can provide new insights.
Wetlands differ from terrestrial systems in conditions (e.g. soil water saturation, anoxia, pH extremes), plant adaptations (e.g. aerenchyma, clonality, ubiquity of bryophytes) and important processes (e.g. denitrification, peat accumulation, methane emission). Wetland plant adaptations and trait (co‐)variation can be situated along major plant trait trade‐off axes (e.g. the resource economics spectrum), but soil saturation represents a complex stress gradient beyond a simple extension of commonly studied water availability gradients.
Traits that affect ecosystem functioning overlap with patterns in terrestrial systems. But wetland‐specific traits that mediate plant effects on soil redox conditions, microbial communities and on water flow, as well as trait spectra of mosses, vary among wetland types.
Synthesis. With increasing availability of quantitative plant traits a trait‐based ecology of wetlands is emerging, with the potential to advance process‐based understanding and prediction. We provide an interactive cause‐and‐effect framework that may guide research efforts to disentangle the multiple interacting processes involved in scaling from environmental conditions to ecosystem functioning via plant communities.
With the increasing availability of quantitative plant traits a trait‐based ecology of wetlands is emerging, with the potential to advance process‐based understanding and prediction. We provide an interactive cause‐and‐effect framework that may guide research efforts to disentangle the multiple interacting processes involved in scaling from environmental conditions to ecosystem functioning via plant communities.
Ethiopia aims to restore 15 million ha degraded forests and woodlands, but effects on the potentially contrasting goals of long-term carbon storage, biodiversity and sustainable livelihoods are ...unknown. To quantify the effects of grazing exclusion on vegetation and fire behaviour, we established six 30 × 30 m fenced exclosures with grazed controls, in a mesic wooded savanna. Experimental burns were done after 1.5 years. Tree seedlings were few but more common inside fences. Field layer cover and biomass increased inside fences, and grass species increased in numbers and cover. Fire intensity was higher inside fences, killing shrubs and saplings but not mature trees. Interviews confirmed that overgrazing has resulted in “
cool fires
”, causing shrub encroachment. High-intensity fires occurred in the 1980s after a zoonotic disease killed most livestock. Short-term increase in carbon storage through fire and grazing exclusion may lead to loss of pasture, and in the long-term increased wildfire risk.
Context
Human-dominated landscapes in the tropics need to be managed for biodiversity and the maintenance of ecosystem services (ES). Nevertheless, integrating both biodiversity conservation and ES ...management remains a challenge.
Objectives
This study aimed to quantify woody plant species diversity and associated ES in farmland and forests, and investigate the relationship between species and ES diversity.
Methods
The study was conducted in southwestern Ethiopia. We surveyed woody plants in 181 20 m by 20 m plots in farmland, forest with, and forest without coffee management. We also interviewed 180 randomly selected households about woody plant benefits. We then (a) quantified species and ES diversity; and (b) investigated the relationship between species and ES diversity.
Results
We recorded 128 woody plant species in total. Most ES were available in all land uses, although they differed in their mean availability. ES composition was significantly different among land uses. ES diversity was positively related with species diversity in all land uses.
Conclusions
Our findings suggest that all examined land-use types were multifunctional in terms of key ES provided by woody plants and that maintaining high species diversity also benefits ES diversity. Given these findings, we suggest to: (1) strengthen landscape multifunctionality by drawing on the positive relationship between biodiversity and ES diversity; (2) devise conservation policies that encompass entire landscape mosaics and enhance co-benefits of conservation and ES provision across land uses; and (3) conduct further social–ecological studies that use mixed data to elicit socially relevant relationships between biodiversity and ES diversity.
Green coffee bean quality and biochemistry are influenced by environmental variables. The present study was designed to study the influence of soil temperatures and soil chemistry on bean physical ...attributes, bean quality (assessed by three internationally trained, experienced, and certified Q-grade cuppers licensed by the Specialty Coffee Association (SCA) Coffee Quality Institute (CQI) and biochemistry of green coffee beans). The study was performed in 53 farms in southwest Ethiopia distributed along an elevational gradients (1500–2160 m a.s.l.) and with varying shade canopy cover (open to dense shade). A total of 159 individual coffee trees were sampled. Shade tree canopy cover, soil temperature, and soil chemistry, as well as coffee management intensity, were quantified as explanatory variables. Green bean quality was negatively correlated to soil temperatures. On the other hand, hundred bean mass and green bean biochemistry (caffeine, trigonelline, and chlorogenic acid contents) were negatively correlated to soil temperatures but positively to soil chemistry. During the coffee fruit development period (flowering to fruit maturity), temperature appeared to be a driving factor influencing coffee bean quality and biochemistry. Total specialty quality was significantly associated with soil chemistry, in which 84% of the variation could be explained by soil chemical variables. This study is the first to demonstrate the relationship between soil temperatures and chemistry in coffee bean quality and green bean biochemical compositions. Although the relative importance of factors such as air temperatures and humidity and soil moisture are missing from this study, we find that soil temperatures and soil chemistry have a strong effect on coffee bean quality and biochemistry. Overall, climate change, which generally involves a substantial increase in mean temperatures of tropical regions, could be expected to have a negative impact on coffee bean quality and biochemistry.
Social-ecological systems are complex and involve uncertainties emerging from interactions between biophysical and social system components. In the face of growing complexity and uncertainty, ...stakeholder engagement with the future is important to proactively manoeuvre toward desirable outcomes. Focusing on the interrelated challenges of food security and biodiversity conservation, we conducted a participatory scenario planning exercise in a rural landscape in southwestern Ethiopia. We involved 35 stakeholder organizations in multiple workshops to construct causal loop diagrams, elicit critical uncertainties, and draft scenario narratives. Jointly, we developed four plausible future scenarios for the studied landscape: (1) gain over grain: local cash crops; (2) mining green gold: coffee investors; (3) coffee and conservation: a biosphere reserve; and (4) food first: intensive farming and forest protection. These scenarios differ with respect to their main social-economic dynamics as well as their food security and biodiversity outcomes. Importantly, three of the four scenarios, i.e., all except "coffee and conservation: a biosphere reserve," focused on increasing efficiency in agricultural production through intensification, specialization, and market integration. In contrast, "coffee and conservation: a biosphere reserve" was driven by agroecological production methods that support diversified livelihoods, a multifunctional landscape, maintenance of natural capital, a governance system that supports local people, and social-ecological resilience. Similar agroecological trajectories have been advocated as desirable for sustainable development in numerous other smallholder farming systems worldwide. Given fewer trade-offs and better equity outcomes, it appears that an agroecological development pathway stands a good chance of generating synergies between food security and biodiversity conservation. Pathways prioritizing agricultural efficiency, in contrast, are more likely to degrade natural capital and cause social inequity.
•Topographic complexity determines the climatic range and patchiness of landscapes.•Heterogeneous landscapes select for better dispersal and wider climatic niches.•Heterogeneity increases species ...pool and decreases distance to track climate niche.•Climatic heterogeneity enhances both resistance and resilience to climate change.•Topography thus drives community assembly dynamics and response to climate change.
In the face of climate change, populations have two survival options − they can remain in situ and tolerate the new climatic conditions (“stay”), or they can move to track their climatic niches (“go”). For sessile and small-stature organisms like alpine plants, staying requires broad climatic tolerances, realized niche shifts due to changing biotic interactions, acclimation through plasticity, or rapid genetic adaptation. Going, in contrast, requires good dispersal and colonization capacities. Neither the magnitude of climate change experienced locally nor the capacities required for staying/going in response to climate change are constant across landscapes, and both aspects may be strongly affected by local microclimatic variation associated with topographic complexity. We combine ideas from population and community ecology to discuss the effects of topographic complexity in the landscape on the immediate “stay” or “go” opportunities of local populations and communities, and on the selective pressures that may have shaped the stay or go capacities of the species occupying contrasting landscapes. We demonstrate, using example landscapes of different topographical complexity, how species’ thermal niches could be distributed across these landscapes, and how these, in turn, may affect many population and community ecological processes that are related to adaptation or dispersal. Focusing on treeless alpine or Arctic landscapes, where temperature is expected to be a strong determinant, our theorethical framework leads to the hypothesis that populations and communities of topographically complex (rough and patchy) landscapes should be both more resistant and more resilient to climate change than those of topographically simple (flat and homogeneous) landscapes. Our theorethical framework further points to how meta-community dynamics such as mass effects in topographically complex landscapes and extinction lags in simple landscapes, may mask and delay the long-term outcomes of these landscape differences under rapidly changing climates.
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