Biological responses to climate change have been widely documented across taxa and regions, but it remains unclear whether species are maintaining a good match between phenotype and environment, i.e. ...whether observed trait changes are adaptive. Here we reviewed 10,090 abstracts and extracted data from 71 studies reported in 58 relevant publications, to assess quantitatively whether phenotypic trait changes associated with climate change are adaptive in animals. A meta-analysis focussing on birds, the taxon best represented in our dataset, suggests that global warming has not systematically affected morphological traits, but has advanced phenological traits. We demonstrate that these advances are adaptive for some species, but imperfect as evidenced by the observed consistent selection for earlier timing. Application of a theoretical model indicates that the evolutionary load imposed by incomplete adaptive responses to ongoing climate change may already be threatening the persistence of species.
We review the evidence of how organisms and populations are currently responding to climate change through phenotypic plasticity, genotypic evolution, changes in distribution and, in some cases, ...local extinction. Organisms alter their gene expression and metabolism to increase the concentrations of several antistress compounds and to change their physiology, phenology, growth and reproduction in response to climate change. Rapid adaptation and microevolution occur at the population level. Together with these phenotypic and genotypic adaptations, the movement of organisms and the turnover of populations can lead to migration toward habitats with better conditions unless hindered by barriers. Both migration and local extinction of populations have occurred. However, many unknowns for all these processes remain. The roles of phenotypic plasticity and genotypic evolution and their possible trade‐offs and links with population structure warrant further research. The application of omic techniques to ecological studies will greatly favor this research. It remains poorly understood how climate change will result in asymmetrical responses of species and how it will interact with other increasing global impacts, such as N eutrophication, changes in environmental N : P ratios and species invasion, among many others. The biogeochemical and biophysical feedbacks on climate of all these changes in vegetation are also poorly understood. We here review the evidence of responses to climate change and discuss the perspectives for increasing our knowledge of the interactions between climate change and life.
Emissions of volatile organic compounds (VOCs) have multiple atmospheric implications and play many roles in plant physiology and ecology. Among these VOCs, growing interest is being devoted to a ...group of short-chain oxygenated VOCs (oxVOCs). Technology improvements such as proton transfer reaction-mass spectrometry are facilitating the study of these hydrocarbons and new data regarding these compounds is continuously appearing. Here we review current knowledge of the emissions of these oxVOCs by plants and the factors that control them, and also provide an overview of sources, sinks, and concentrations found in the atmosphere.
The oxVOCs reviewed here are formic and acetic acids, acetone, formaldehyde, acetaldehyde, methanol, and ethanol. In general, because of their water solubility (low gas–liquid partitioning coefficient), the plant-atmosphere exchange is stomatal-dependent, although it can also take place via the cuticle. This exchange is also determined by atmospheric mixing ratios. These compounds have relatively long atmospheric half-lives and reach considerable concentrations in the atmosphere in the range of ppbv. Likewise, under non-stressed conditions plants can emit all of these oxVOCs together at fluxes ranging from 0.2 up to 4.8
μg(C)g
−1(leaf dry weight)h
−1 and at rates that increase several-fold when under stress.
Gaps in our knowledge regarding the processes involved in the synthesis, emission, uptake, and atmospheric reactivity of oxVOCs precludes the clarification of exactly what is conditioning plant-atmosphere exchange—and also when, how, and why this occurs—and these lacunae therefore warrant further research in this field.
Mountains are vital ecosystems, yet predicting plant growth there is complex due to diverse microclimates on slopes. Equatorial‐facing slopes (EFSs) are drier and warmer, and polar‐facing slopes ...(PFSs) are wetter and colder, than their regional macroclimates. Analyzing Moderate Resolution Imaging Spectroradiometer normalized difference vegetation index from 2003 to 2021, we identified a clear geographic pattern of differences in greenness on the two opposite aspects: EFSs were greener than PFSs in cold areas and were browner in dry areas, mainly determined by the relative importance of limitations of temperature and water. PFSs had stronger greening trends than did EPSs, leading to a weakening difference in greenness between EPSs and PFSs in temperature‐limited areas, and an intensifying difference in water‐limited areas. This suggests the alleviation of temperature limitation and exacerbation of water limitation. Montane ecosystems constitute a “natural laboratory” for deepening our understanding of the temporal evolution of the climatic control of vegetation growth with a space‐for‐time substitution.
Plain Language Summary
Mountains are essential for Earth's greenery, but understanding plant growth in these landscapes is complex due to varied microclimates on slopes. Some slopes are drier and warmer, while others are wetter and colder than the surrounding areas. These micro‐habitats influence how plants respond to changing climates. Using satellite data from 2003 to 2021, we found that slopes facing the equator are greener in cold areas but browner in dry zones. Slopes facing the poles have stronger greening trends than equatorial slopes. Our research reveals how mountain plants adapt to local conditions, offering insights into how they might respond to climate changes. Mountains act as nature's laboratories, guiding us in understanding how temperature and water shape plant growth over time.
Key Points
Microclimatic disparities between Equatorial‐facing slopes (EFSs) and polar‐facing slopes (PFSs) shape distinct vegetation dynamics
Global study reveals EFSs greener in colder regions, while PFSs show stronger greening trends, reflecting changing climate limitations
Montane ecosystems provide insights into climate‐driven vegetation growth, indicating temperature and water play pivotal roles
Currently, a global analysis of the information available on the relative composition of the floral scents of a very diverse variety of plant species is missing. Such analysis may reveal general ...patterns on the distribution and dominance of the volatile compounds that form these mixtures, and may also allow measuring the effects of factors such as the phylogeny, pollination vectors, and climatic conditions on the floral scents of the species. To fill this gap, we compiled published data on the relative compositions and emission rates of volatile organic compounds (VOCs) in the floral scents of 305 plant species from 66 families. We also gathered information on the groups of pollinators that visited the flowers and the climatic conditions in the areas of distribution of these species. This information allowed us to characterize the occurrence and relative abundances of individual volatiles in floral scents and the effects of biotic and climatic factors on floral scent. The monoterpenes trans-β-ocimene and linalool and the benzenoid benzaldehyde were the most abundant floral VOCs, in both ubiquity and predominance in the floral blends. Floral VOC richness and relative composition were moderately preserved traits across the phylogeny. The reliance on different pollinator groups and the climate also had important effects on floral VOC richness, composition, and emission rates of the species. Our results support the hypothesis that key compounds or compounds originating from specific biosynthetic pathways mediate the attraction of the main pollinators. Our results also indicate a prevalence of monoterpenes in the floral blends of plants that grow in drier conditions, which could link with the fact that monoterpene emissions protect plants against oxidative stresses throughout drought periods and their emissions are enhanced under moderate drought stress. Sesquiterpenes, in turn, were positively correlated with mean annual temperature, supporting that sesquiterpene emissions are dominated mainly by ambient temperature. This study is the first to quantitatively summarise data on floral-scent emissions and provides new insights into the biotic and climatic factors that influence floral scents.
The available data on climate over the past century indicate that the earth is warming. Important biological effects, including changes of plant and animal life cycle events, have already been ...reported. However, evidence of such effects is still scarce and has been mostly limited to northern latitudes. Here we provide the first long‐term (1952–2000) evidence of altered life cycles for some of the most abundant Mediterranean plants and birds, and one butterfly species. Average annual temperatures in the study area (Cardedeu, NE Spain) have increased by 1.4 °C over the observation period while precipitation remained unchanged. A conservative linear treatment of the data shows that leaves unfold on average 16 days earlier, leaves fall on average 13 days later, and plants flower on average 6 days earlier than in 1952. Fruiting occurs on average 9 days earlier than in 1974. Butterflies appear 11 days earlier, but spring migratory birds arrive 15 days later than in 1952. The stronger changes both in temperature and in phenophases timing occurred in the last 25 years. There are no significant relationships among changes in phenophases and the average date for each phenophase and species. There are not either significant differences among species with different Raunkiaer life‐forms or different origin (native, exotic or agricultural). However, there is a wide range of phenological alterations among the different species, which may alter their competitive ability, and thus, their ecology and conservation, and the structure and functioning of ecosystems. Moreover, the lengthening of plant growing season in this and other northern hemisphere regions may contribute to a global increase in biospheric activity.
Remote sensing detection of autumn phenology is challenging and highly uncertain, as exemplified by the observed divergence in autumn phenology extracted from different proxies. Here, we compared the ...autumn phenology derived from Solar‐Induced chlorophyll Fluorescence (SIF), Chlorophyll/Carotenoid Index (CCI), Enhanced Vegetation Index (EVI), and Normalized Difference Vegetation Index (NDVI) over deciduous forest sites. We observed a clear temporal sequence in the derived autumn phenology from various proxies: SIF < CCI < EVI < NDVI. Comparison with field measurements supported that SIF, EVI, and NDVI can successfully capture the attenuation of photosynthetic activity, leaf coloration, and leaf fall, respectively. The sequence among the autumn phenology derived from those proxies was also consistent with their responses to climate cues, where SIF had the highest partial correlation coefficient to solar radiation in autumn, followed by CCI, EVI, and NDVI, while NDVI was more correlated with temperature, followed by EVI, CCI, and SIF.
Plain Language Summary
The autumn phenology of deciduous forests is critical for estimating carbon sequestration and understanding the responses of vegetation to climate change. However, the autumn phenology metrics derived from different satellite proxies show high discrepancies. Here, we hypothesized that leaf senescence of deciduous forests is a progressive process, and that the different satellite proxies capture different stages of this timetable. To test this hypothesis, we compared the autumn phenology of deciduous forests derived from Solar‐Induced chlorophyll Fluorescence (SIF), Chlorophyll/Carotenoid Index (CCI), Enhanced Vegetation Index (EVI), and Normalized Difference Vegetation Index (NDVI). We revealed the timetable of autumn phenology derived from different satellite proxies, that is, SIF‐based autumn phenology is the earliest, followed by CCI‐based, EVI‐based, and NDVI‐based autumn phenology, which had a close relationship with their responses to temperature and solar radiation in autumn. Comparison with field measurements supported that SIF, EVI, and NDVI can successfully capture the attenuation of photosynthetic activity, leaf coloration, and leaf fall, respectively, which occur in sequence during the leaf senescence process. These findings improved our understanding on the meaning of remote sensing derived autumn phenology, and will contribute to the accurate estimation of the length of photosynthetic active season.
Key Points
The sequence among the autumn phenology derived from satellite proxies is Solar‐Induced chlorophyll Fluorescence (SIF) < Chlorophyll/Carotenoid Index (CCI) < Enhanced Vegetation Index (EVI) < Normalized Difference Vegetation Index (NDVI)
SIF, CCI, EVI, and NDVI capture different stages of senescence of deciduous forests
This sequence among autumn phenology derived from SIF, CCI, EVI, and NDVI is consistent with their responses to climate cues
In this work we analyzed the degradation of floral scent volatiles from Brassica nigra by reaction with ozone along a distance gradient and the consequences for pollinator attraction. For this ...purpose we used a reaction system comprising three reaction tubes in which we conducted measurements of floral volatiles using a proton‐transfer‐reaction time‐of‐flight mass spectrometer (PTR‐TOF‐MS) and GC‐MS. We also tested the effects of floral scent degradation on the responses of the generalist pollinator Bombus terrestris. The chemical analyses revealed that supplementing air with ozone led to an increasing reduction in the concentrations of floral volatiles in air with distance from the volatile source. The results revealed different reactivities with ozone for different floral scent constituents, which emphasized that ozone exposure not only degrades floral scents, but also changes the ratios of compounds in a scent blend. Behavioural tests revealed that floral scent was reduced in its attractiveness to pollinators after it had been exposed to 120 ppb O₃ over a 4.5 m distance. The combined results of chemical analyses and behavioural responses of pollinators strongly suggest that high ozone concentrations have significant negative impacts on pollination by reducing the distance over which floral olfactory signals can be detected by pollinators.
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