Results
- Showing results for:
- Reset all filters
Search results
-
Journal articleAguirre-Gutierrez J, Berenguer E, Menor IO, et al., 2022,
Functional susceptibility of tropical forests to climate change
, NATURE ECOLOGY & EVOLUTION, Vol: 6, Pages: 878-+, ISSN: 2397-334X- Author Web Link
- Cite
- Citations: 5
-
Journal articleChristensen AK, Piggott M, van Sebille E, et al., 2022,
Investigating microscale patchiness of motile microbes under turbulence in a simulated convective mixed layer
, PLOS COMPUTATIONAL BIOLOGY, Vol: 18, ISSN: 1553-734X -
Journal articleParra-Sanchez E, Banks-Leite C, 2022,
Value of human-modified forests for the conservation of canopy epiphytes
, BIOTROPICA, Vol: 54, Pages: 958-968, ISSN: 0006-3606 -
Journal articleCruz-Silva E, Harrison SP, Marinova-Wolff E, et al., 2022,
A new method based on surface- sample pollen data for reconstructing palaeovegetation patterns.
, Journal of Biogeography, Vol: 49, Pages: 1381-1396, ISSN: 0305-0270Aim: Amongst the various techniques available to reconstruct past vegetation at regional to continental scales, biomisation has been the most widely used because it does not require an extensive modern pollen data set. However, it has well well-known limitations including its dependence on expert judgement for the assignment of pollen taxa to plant functional types (PFTs) and PFTs to biomes. Here we present a new method that combines the strengths of biomisation with those of the alternative dissimilarity-based techniques. This new technique quantifies the likelihood that a sample belongs to a given biome, and allows discrimination of non-analogue vegetation types. Location: The Eastern Mediterranean-Black Sea Caspian Corridor (EMBSeCBIO) region, 28°-49°N, 20°- 62°E. Methods: Modern pollen samples assigned to biomes based on potential natural vegetation data, are used to characterize biomes according to the within-biome means and standard deviations of the abundances of each taxon. These are used to calculate a dissimilarity index between any given pollen sample and every biome, and thus assign a pollen sample to the most likely biome. We also calculate a threshold value for each biome which identifies samples that fall outside the acceptable range of likelihoods for biome assignment and hence can be used to distinguish non-analogue vegetation. We have applied the new technique to the EMBSeCBIO region to compare the performance of the new method with existing reconstructions. Results: The technique captured changes in the importance of individual taxa along environmental gradients. The balanced accuracy obtained for the EMBSeCBIO region using the new method was better than that obtained using biomisation (77% versus 65%). When the method was applied to high resolution fossil records, 70% of the evaluated entities showed more temporally stable biome assignments than obtained with the biomisation method. The technique also identifies likely non analogu
-
Journal articleWeeks BC, O'Brien BK, Chu JJ, et al., 2022,
Morphological adaptations linked to flight efficiency and aerial lifestyle determine natal dispersal distance in birds
, Functional Ecology, Vol: 36, Pages: 1681-1689, ISSN: 0269-8463Natal dispersal—the movement from birthplace to breeding location—is often considered the most significant dispersal event in an animal's lifetime. Natal dispersal distances may be shaped by a variety of intrinsic and extrinsic factors, and remain poorly quantified in most groups, highlighting the need for indices that capture variation in dispersal among species.In birds, it is hypothesized that dispersal distance can be predicted by flight efficiency, which can be estimated using wing morphology. However, the use of morphological indices to predict dispersal remains contentious and the mechanistic links between flight efficiency and natal dispersal are unclear.Here, we use phylogenetic comparative models to test whether hand-wing index (HWI, a morphological proxy for wing aspect ratio) predicts natal dispersal distance across a global sample of 114 bird species. In addition, we assess whether HWI is correlated with flight usage in foraging and daily routines.We find that HWI is a strong predictor of both natal dispersal distance and a more aerial lifestyle.Our results support the use of HWI as a valid proxy for relative natal dispersal distance, and also suggest that evolutionary adaptation to aerial lifestyles is a major factor connecting flight efficiency with patterns of natal dispersal.
-
Journal articleCheng S, Jin Y, Harrison SP, et al., 2022,
Parameter flexible wildfire prediction using machine learning techniques:forward and inverse modelling
, Remote Sensing, ISSN: 2072-4292 -
Journal articleIglesias-Carrasco M, Tobias JA, Duchene DA, 2022,
Bird lineages colonizing urban habitats have diversified at high rates across deep time
, Global Ecology and Biogeography, Vol: 31, Pages: 1784-1793, ISSN: 1466-822XAimUrbanization exposes species to novel ecological conditions. Some species thrive in urban areas, whereas many others are excluded from these human-made environments. Previous analyses suggest that the ability to cope with rapid environmental change is associated with long-term patterns of diversification, but whether the suite of traits associated with the ability to colonize urban environments is linked to this process remains poorly understood.LocationWorld.Time periodCurrent.Major taxa studiedPasserine birds.MethodsWe applied macroevolutionary models to a large dataset of passerine birds to compare the evolutionary history of urban-tolerant species with that of urban-avoidant species. Specifically, we examined models of state-dependent speciation and extinction to assess the macroevolution of urban tolerance as a binary trait, in addition to models of quantitative trait-dependent diversification based on relative urban abundance. We also ran simulation-based model assessments to explore potential sources of bias.ResultsWe provide evidence that historically, species with traits promoting urban colonization have undergone faster diversification than urban-avoidant species, indicating that urbanization favours clades with a historical tendency towards rapid speciation or reduced extinction. In addition, we find that past transitions towards states that currently impede urban colonization by passerines have been more frequent than in the opposite direction. Furthermore, we find a portion of urban-avoidant passerines to be recent and to undergo fast diversification. All highly supported models give this result consistently.Main conclusionsUrbanization is mainly associated with the loss of lineages that are inherently more vulnerable to extinction over deep time, whereas cities tend to be colonized by less vulnerable lineages, for which urbanization might be neutral or positive in terms of longer-term diversification. Urban avoidance is associated with high rates of
-
Journal articleKeenan TFC, Luo X, De Kauwe MG, et al., 2022,
A constraint on historic growth in global photosynthesis due to increasing CO<sub>2</sub> (Retraction of Vol 600, Pg 253, 2021)
, NATURE, Vol: 606, Pages: 420-420, ISSN: 0028-0836 -
Journal articleBanks-Leite C, Betts MG, Ewers RM, et al., 2022,
The macroecology of landscape ecology
, Trends in Ecology and Evolution, Vol: 37, ISSN: 0169-5347One of landscape ecology's main goals is to unveil how biodiversity is impacted by habitat transformation. However, the discipline suffers from significant context dependency in observed spatial and temporal trends, hindering progress towards understanding the mechanisms driving species declines and preventing the development of accurate estimates of future biodiversity change. Here, we discuss recent evidence that populations' and species' responses to habitat change at the landscape scale are modulated by factors and processes occurring at macroecological scales, such as historical disturbance rates, distance to geographic range edges, and climatic suitability. We suggest that placing landscape ecology studies in a macroecological lens will help to explain seemingly inconsistent results and will ultimately create better predictive models to help mitigate the biodiversity crisis.
-
Journal articleWang H, Wang R, Harrison SP, et al., 2022,
Leaf morphological traits as adaptations to multiple climate gradients
, Journal of Ecology, Vol: 110, Pages: 1344-1355, ISSN: 0022-04771. Leaf morphological traits vary systematically along climatic gradients. However, recent studies in plant functional ecology have mainly analysed quantitative traits, while numerical models of species distributions and vegetation function have focused on traits associated with resource acquisition; both ignore the wider functional significance of leaf morphology.2. A data set comprising 22 leaf morphological traits for 662 woody species from 92 sites, representing all biomes present in China, was subjected to multivariate analysis in order to identify leading dimensions of trait covariation (correspondence analysis), quantify climatic and phylogenetic contributions (canonical correspondence analysis with variation partitioning), and characterize co-occurring trait syndromes (k-means clustering) and their climatic preferences. 3. Three axes accounted for > 20% of trait variation in both evergreen and deciduous species. Moisture index, precipitation seasonality and growing-season temperature accounted for 8–10% of trait variation; family 15–32%. Microphyll or larger, mid- to dark green leaves with drip-tips in wetter climates contrasted with nanophyll or smaller glaucous leaves without drip-tips in drier climates. Thick, entire leaves in less seasonal climates contrasted with thin, marginal dissected, aromatic, and involute/revolute leaves in more seasonal climates. Thick, involute, hairy leaves in colder climates contrasted with thin leaves with marked surface structures (surface patterning) in warmer climates. Distinctive trait clusters were linked to the driest and most seasonal climates, for example the clustering of picophyll, fleshy and succulent leaves in the driest climates and leptophyll, linear, dissected, revolute or involute, and aromatic leaves in regions with highly seasonal rainfall. Several trait clusters co-occurred in wetter climates, including clusters characterised by microphyll, moderately thick, patent, and entire leaves or notop
-
Journal articleDeere NJ, Bicknell JE, Mitchell SL, et al., 2022,
Riparian buffers can help mitigate biodiversity declines in oil palm agriculture
, Frontiers in Ecology and the Environment, Vol: 20, Pages: 459-466, ISSN: 1540-9295Agricultural expansion is a primary driver of biodiversity decline in forested regions of the tropics. Consequently, it is important to understand the conservation value of remnant forests in production landscapes. In a tropical landscape dominated by oil palm (Elaeis guineensis), we characterized faunal communities across eight taxa occurring within riparian forest buffers, which are legally protected alongside rivers, and compared them to nearby recovering logged forest. Buffer width was the main predictor of species richness and abundance, with widths of 40–100 m on each side of the river supporting broadly equivalent levels of biodiversity as compared to logged forest. However, width responses varied markedly among taxa, and buffers often lacked forest-dependent species. Much wider buffers than are currently mandated are needed to safeguard most species. The largest biodiversity gains are achieved by increasing relatively narrow buffers. To provide optimal conservation outcomes in tropical production landscapes, we encourage policy makers to prescribe width requirements for key taxa and different landscape contexts.
-
Journal articleShen Y, Sweeney L, Liu M, et al., 2022,
Reconstructing burnt area during the Holocene: an Iberian case study
, Climate of the Past, Vol: 18, Pages: 1189-1201, ISSN: 1814-9324Charcoal accumulated in lake, bog or other anoxic sediments through time has been used to document the geographical patterns in changes in fire regimes. Such reconstructions are useful to explore the impact of climate and vegetation changes on fire during periods when human influence was less prevalent than today. However, charcoal records only provide semi-quantitative estimates of change in biomass burning. Here we derive quantitative estimates of burnt area from vegetation data in two stages. First, we relate the modern charcoal abundance to burnt area using a conversion factor derived from a generalised linear model of burnt area probability based on eight environmental predictors. Then, we establish the relationship between fossil pollen assemblages and burnt area using tolerance-weighted weighted averaging partial least-squares regression with a sampling frequency correction (fxTWA-PLS). We test this approach using the Iberian Peninsula as a case study because it is a fire-prone region with abundant pollen and charcoal records covering the Holocene. We derive the vegetation–burnt area relationship using the 31 records that have both modern and fossil charcoal and pollen data and then reconstruct palaeoburnt area for the 113 records with Holocene pollen records. The pollen data predict charcoal-derived burnt area relatively well (R2 = 0.44), and the changes in reconstructed burnt area are synchronous with known climate changes through the Holocene. This new method opens up the possibility of reconstructing changes in fire regimes quantitatively from pollen records, after regional calibration of the vegetation–burnt area relationship, in regions where pollen records are more abundant than charcoal records.
-
Journal articleBennett S, Girndt A, Sanchez-Tojar A, et al., 2022,
Evidence of Paternal Effects on Telomere Length Increases in Early Life
, FRONTIERS IN GENETICS, Vol: 13- Author Web Link
- Cite
- Citations: 2
-
Journal articleHaas O, Prentice IC, Harrison SP, 2022,
Global environmental controls of wildfire burnt area, size and intensity.
, Environmental Research Letters, Vol: 17, Pages: 1-12, ISSN: 1748-9326Fire is an important influence on the global patterns of vegetation structure and composition. Wildfire is included as a distinct process in many dynamic global vegetation models but limited current understanding of fire regimes restricts these models' ability to reproduce more than the broadest geographic patterns. Here we present a statistical analysis of the global controls of remotely sensed burnt area (BA), fire size (FS), and a derived metric related to fire intensity (FI). Separate generalized linear models were fitted to observed monthly fractional BA from the Global Fire Emissions Database (GFEDv4), median FS from the Global Fire Atlas, and median fire radiative power from the MCD14ML dataset normalized by the square root of median FS. The three models were initially constructed from a common set of 16 predictors; only the strongest predictors for each model were retained in the final models. It is shown that BA is primarily driven by fuel availability and dryness; FS by conditions promoting fire spread; and FI by fractional tree cover and road density. Both BA and FS are constrained by landscape fragmentation, whereas FI is constrained by fuel moisture. Ignition sources (lightning and human population) were positively related to BA (after accounting for road density), but negatively to FI. These findings imply that the different controls on BA, FS and FI need to be considered in process-based models. They highlight the need to include measures of landscape fragmentation as well as fuel load and dryness, and to pay close attention to the controls of fire spread.
-
Journal articleMUMFORD JD, QUINLAN MM, 2022,
Introduction
, Revue Scientifique et Technique de l'OIE, Vol: 41, Pages: 15-28, ISSN: 0253-1933 -
Journal articleOLIVA CF, CHAND R, PRUDHOMME J, et al., 2022,
International live insect trade: a survey of stakeholders
, Revue Scientifique et Technique de l'OIE, Vol: 41, Pages: 29-65, ISSN: 0253-1933There are significant numbers of transboundary shipments of live insects for pollination, pest management, industrialprocesses, research and other uses, but data collection and analysis have proved difficult. The World Organisation forAnimal Health and Collectif TIS (Technique de l’Insecte Stérile), a French think tank, carried out a stakeholder surveyto understand the nature of the live insect trade and potential challenges to safety and efficiency. Target respondentshad experience in the areas of biocontrol, sterile insect technique, entomological research and regulatory affairs.Although the survey was sent globally, the responses were unintentionally biased towards Europe, where interest ishigh, since this region is developing a comprehensive framework to promote the use of beneficial insects to replacepesticides.The survey also explored respondents’ knowledge of several international agreements on the movement and riskmanagement of beneficial or invasive insects. Knowledge of the various regulations was generally poor, and respondents highlighted a perceived lack of clarity regarding live insect shipments in the existing international regulationsand guidelines. Almost two-thirds of participants reported reluctance by carriers to accept live insects for shipment,and three-quarters described occasional to systematic delays that resulted in a reduction of quality or viability. Somerespondents reported that they instead hand-carry live insects, mostly in small quantities.Participants described being directly involved in trade covering 70 species of live insects and ticks transportedamong 37 countries, with volumes ranging from fewer than ten insects to over a million per shipment. Of these, 30%were potential vectors of pathogens to humans or animals, 42% were potential plant pest species (including someused for biocontrol), and 17% were classical biocontrol agents.The results of this survey begin to define the current scope, scale and issues for t
-
Journal articleQUINLAN MM, MUMFORD JD, MESSORI S, et al., 2022,
Issues and gaps in international guidance and national regulatory systems affecting international live insect trade
, Revue Scientifique et Technique de l'OIE, Vol: 41, Pages: 198-210, ISSN: 0253-1933International trade in live insects involves the shipping of many different species, for various purposes, with a varietyof handling requirements regulated by numerous authorities with varying objectives. The diversity of factors at playhas both created and been subject to a complex regulatory landscape. A review of global production, shipping and useexperiences from a range of perspectives has shown gaps and inconsistencies in international guidance and nationalimplementation. Private carriers add another layer of uncertainty that is disproportionate to risks, resulting in variablepractices and charges.Many benefits can come from international trade in insects, including pollinator services, control of pests and of disease vectors, and enhanced international scientific research and innovation. These benefits will be better achievedthrough a more evidence-based and efficient approach to regulating trade. This change in approach will in turn require an improved and widely accepted risk-management landscape for insect trade.
-
Journal articleMUMFORD JD, QUINLAN MM, 2022,
Opportunities and recommendations for improved international shipment of live insects
, Revue Scientifique et Technique de l'OIE, Vol: 41, Pages: 228-250, ISSN: 0253-1933While the information on live insect shipments provided in this thematic issue of the Scientific and Technical Reviewcould not be exhaustive, it clearly represents a broad variety of trade, of substantial value, involving many stakeholdersthroughout the world. The contributions to this issue demonstrate that most of the trade in insects is carried out safelyand efficiently. The concerns related to shipping insects described within this issue fall broadly into four categories:risks to human, animal and environmental health; delays and loss of quality; refusal of carriage; and high and variablecosts. Some opportunities for improvements to insect shipping for diverse stakeholders are shown across these fourareas of concern, with specific recommendations and a general call for further collaboration among stakeholders.
-
Journal articleQUINLAN MM, MUMFORD JD, BENEDICT MQ, et al., 2022,
Can there be a common, risk-based framework for decisions around live insect trade?
, Revue Scientifique et Technique de l'OIE, Vol: 41, Pages: 219-227, ISSN: 0253-1933A network of scientists involved in shipment of live insects has met and generated a series of articles on issues relatedto live insect transport. The network is diverse, covering large-scale commercial interests, government operated areawide control programmes, biomedical research and many smaller applications, in research, education and privateuses. Many insect species have a record of safe transport, pose minimal risks and are shipped frequently betweencountries. The routine shipments of the most frequently used insect model organism for biomedical research,Drosophila melanogaster, is an example. Successful large-scale shipments from commercial biocontrol and pollinatorsuppliers also demonstrate precedents for low-risk shipment categories, delivered in large volumes to high qualitystandards. Decision makers need access to more information (publications or official papers) that details actual risksfrom the insects themselves or their possible contaminants, and should propose proportionate levels of management.There may be harm to source environments when insects are collected directly from the wild, and there may be harmhttps://doi.org/10.20506/rst.41.1.3319Scientific and Technical Review 41 (1) 2022 220to receiving environments. Several risk frameworks include insects and various international coordinating bodies,with experience of guidance on relevant risks, exist. All stakeholders would benefit from an integrated overview ofguidance for insect shipping, with reference to types of risk and categories of magnitude, without trying for a singleapproach requiring universal agreement. Proposals for managing uncertainty and lack of data for smaller or infrequent shipments, for example, must not disrupt trade in large volumes of live insects, which are already supportingstrategic objectives in several sectors.
-
Journal articleLembrechts JJ, van den Hoogen J, Aalto J, et al., 2022,
Global maps of soil temperature
, Global Change Biology, Vol: 28, Pages: 3110-3144, ISSN: 1354-1013Research in global change ecology relies heavily on global climatic grids derived from estimates of air temperature in open areas at around 2 m above the ground. These climatic grids do not reflect conditions below vegetation canopies and near the ground surface, where critical ecosystem functions occur and most terrestrial species reside. Here, we provide global maps of soil temperature and bioclimatic variables at a 1-km2 resolution for 0–5 and 5–15 cm soil depth. These maps were created by calculating the difference (i.e. offset) between in situ soil temperature measurements, based on time series from over 1200 1-km2 pixels (summarized from 8519 unique temperature sensors) across all the world's major terrestrial biomes, and coarse-grained air temperature estimates from ERA5-Land (an atmospheric reanalysis by the European Centre for Medium-Range Weather Forecasts). We show that mean annual soil temperature differs markedly from the corresponding gridded air temperature, by up to 10°C (mean = 3.0 ± 2.1°C), with substantial variation across biomes and seasons. Over the year, soils in cold and/or dry biomes are substantially warmer (+3.6 ± 2.3°C) than gridded air temperature, whereas soils in warm and humid environments are on average slightly cooler (−0.7 ± 2.3°C). The observed substantial and biome-specific offsets emphasize that the projected impacts of climate and climate change on near-surface biodiversity and ecosystem functioning are inaccurately assessed when air rather than soil temperature is used, especially in cold environments. The global soil-related bioclimatic variables provided here are an important step forward for any application in ecology and related disciplines. Nevertheless, we highlight the need to fill remaining geographic gaps by collecting more in situ measurements of microclimate conditions to further enhance the spatiotemporal resolution of global soil temperature products for ecolog
-
Journal articleAlif Ž, Dunning J, Chik HYJ, et al., 2022,
What is the best fitness measure in wild populations? A case study on the power of short-term fitness proxies to predict reproductive value
, PLoS One, Vol: 17, ISSN: 1932-6203Fitness is at the core of evolutionary theory, but it is difficult to measure accurately. One way to measure long-term fitness is by calculating the individual's reproductive value, which represents the expected number of allele copies an individual passes on to distant future generations. However, this metric of fitness is scarcely used because the estimation of individual's reproductive value requires long-term pedigree data, which is rarely available in wild populations where following individuals from birth to death is often impossible. Wild study systems therefore use short-term fitness metrics as proxies, such as the number of offspring produced. This study compared two frequently used short-term metrics for fitness obtained at different offspring life stages (eggs, hatchlings, fledglings and recruits), and compared their ability to predict reproductive values derived from the genetic pedigree of a wild passerine bird population. We used twenty years of precise field observations and a near-complete genetic pedigree to calculate reproductive success, individual growth rate and de-lifed fitness as lifetime fitness measures, and as annual de-lifed fitness. We compared the power of these metrics to predict reproductive values and lineage survival to the end of the study period. The three short-term fitness proxies predict the reproductive values and lineage survival only when measured at the recruit stage. There were no significant differences between the different fitness proxies at the same offspring stages in predicting the reproductive values and lineage survival. Annual fitness at one year old predicted reproductive values equally well as lifetime de-lifed fitness. However, none of the short-term fitness proxies were strongly associated with the reproductive values. The commonly used short-term fitness proxies best predict long-term fitness when measured at recruitment stage. Thus, because lifetime fitness measured at recruit stage and annual fitness in the
-
Journal articleKordas RL, Pawar S, Kontopoulos D-G, et al., 2022,
Metabolic plasticity can amplify ecosystem responses to global warming
, NATURE COMMUNICATIONS, Vol: 13- Author Web Link
- Cite
- Citations: 4
-
Journal articleCavender-Bares J, Nelson E, Meireles JE, et al., 2022,
The hidden value of trees: quantifying the ecosystem services of tree lineages and their major threats across the continental US
, PLoS -
Journal articleYordanova M, Evison SEF, Gill RJ, et al., 2022,
The threat of pesticide and disease co-exposure to managed and wild bee larvae
, International Journal for Parasitology: Parasites and Wildlife, Vol: 17, Pages: 319-326, ISSN: 2213-2244Brood diseases and pesticides can reduce the survival of bee larvae, reduce bee populations, and negatively influence ecosystem biodiversity. However, major gaps persist in our knowledge regarding the routes and implications of co-exposure to these stressors in managed and wild bee brood. In this review, we evaluate the likelihood for co-exposure to brood pathogen and pesticide stressors by examining the routes of potential co-exposure and the possibility for pollen and nectar contaminated with pathogens and pesticides to become integrated into brood food. Furthermore, we highlight ways in which pesticides may increase brood disease morbidity directly, through manipulating host immunity, and indirectly through disrupting microbial communities in the guts of larvae, or compromising brood care provided by adult bees. Lastly, we quantify the brood research bias towards Apis species and discuss the implications the bias has on brood disease and pesticide risk assessment in wild bee communities. We advise that future studies should place a higher emphasis on evaluating bee brood afflictions and their interactions with commonly encountered stressors, especially in wild bee species.
-
Journal articleDobson B, Barry S, Maes-Prior R, et al., 2022,
Predicting catchment suitability for biodiversity at national scales
<jats:title>Abstract</jats:title><jats:p>Biomonitoring of water quality and catchment management are often disconnected, due to mismatching scales. Great effort and money is spent each year on routine reach-scale surveying across many sites, particularly in the UK, and typically with a focus on pre-defined indicators of organic pollution to compare observed vs expected subsets of common macroinvertebrate indicator species. Threatened species are often ignored due to their rarity as are many invasive species, which are seen as undesirable even though they are increasingly common in freshwaters, especially in urban ecosystems. However, these taxa are monitored separately for reasons related to biodiversity concerns rather than for gauging water quality. Repurposing such monitoring data could therefore provide important new biomonitoring tools that can help catchment managers to directly link the water quality that they aim to control with the biodiversity that they are trying to protect. Here we used the England Non-Native and Rare/Protected species records that track these two groups of species as a proof-of-concept for linking catchment scale management of freshwater ecosystems and biodiversity to a range of potential drivers across England. We used national land use (Centre for Ecology and Hydrology land cover map) and water quality indicator (Environment Agency water quality data archive) datasets to predict the presence or absence of 48 focal threatened or invasive species of concern routinely sampled by the English Environment Agency at catchment scale, with a median accuracy of 0.81 area under the receiver operating characteristic curve. A variety of water quality indicators and land-use types were useful in predictions, highlighting that future biomonitoring schemes could use such complementary measures to capture a wider spectrum of drivers and responses. In particular, the percentage of a catchment covered by freshwater was the single most
-
Journal articleHenson SA, Laufkotter C, Leung S, et al., 2022,
Uncertain response of ocean biological carbon export in a changing world
, NATURE GEOSCIENCE, Vol: 15, Pages: 248-254, ISSN: 1752-0894- Author Web Link
- Cite
- Citations: 25
-
Journal articlePrentice IC, Villegas-Diaz R, Harrison SP, 2022,
Accounting for atmospheric carbon dioxide variations in pollen-based reconstructions of past hydroclimates.
, Global and Planetary Change, Vol: 211, Pages: 1-9, ISSN: 0921-8181Changes in atmospheric carbon dioxide (CO2) concentration directly influence the ratio of stomatal water loss to carbon uptake. This ratio (e) is a fundamental quantity for terrestrial ecosystems, as it defines the water requirement for plant growth. Statistical and analogue-based methods used to reconstruct past hydroclimate variables from fossil pollen assemblages do not take account of the effect of CO2 variations on e. Here we present a general, globally applicable method to correct for this effect. The method involves solving an equation that relates e to a climatic moisture index (MI, the ratio of mean annual precipitation to mean annual potential evapotranspiration), mean growing-season temperature, and ambient CO2. The equation is based on the least-cost optimality hypothesis, which predicts how the ratio (χ) of leaf-internal to ambient CO2 varies with vapour pressure deficit (vpd), growing-season temperature and atmospheric pressure, combined with experimental evidence on the response of χ to the CO2 level at which plants have been grown. An empirical relationship based on global climate data is used to relate vpd to MI and growing-season temperature. The solution to the equation allows past MI to be estimated from pollen-reconstructed MI, given past CO2 and temperature. This MI value can be used to estimate mean annual precipitation, accounting for the effects of orbital variations, temperature and cloud cover (inferred from MI) on potential evapotranspiration. A pollen record from semi-arid Spain that spans the last glacial interval is used to illustrate the method. Low CO2 leads to estimated MI being larger than reconstructed MI during glacial times. The CO2 effect on inferred precipitation was partly offset by increased cloud cover; nonetheless, inferred precipitation was greater than present almost throughout the glacial period. This method allows a more robust reconstruction of past hydroclimatic variations than currently available tools.
-
Journal articleGan W, Nóbrega R, Prentice IC, 2022,
Analysis of vegetation modelling uncertainties due to soil moisture stress during droughts
<jats:p>&lt;p&gt;Many model uncertainties results from parameter tuning to compensate for errors in model outputs. A number of studies have focused on the analysis of uncertainties in modelled gross primary production (GPP), particularly with regard to the representation of soil moisture stress. GPP is often overestimated by models during dry periods in water-limited regions, and this bias increases during drought events. Soil moisture stress functions are widely applied to correct this. However, soil moisture stress is not always the direct constraining factor on GPP, and the functions adopted by models do not correspond to accepted mechanisms. We have used eco-evolutionary optimality principles, via the so-called P model, to estimate carbon uptake at sites where leaf area index (LAI) was routinely measured. We used observational networks (including FLUXNET) and Fraction of Absorbed Photosynthetically Active Radiation (fAPAR) data from satellites. By comparing modelled and observed GPP we determined whether there is a significant difference between model performance during the dry and wet seasons, or between energy- and water-limited sites. We found that the soil moisture stress function used in one version of the P models essentially compensates for uncertainties in fAPAR data from satellites, especially in grasslands and other areas subject to seasonal drought. This situation is problematic, since soil moisture is a driver or modulator of other ecosystem processes, including soil evaporation and runoff generation. A possible way forward involves implementing phenological components dependent on soil and atmospheric conditions. The new challenge this poses is to apply eco-evolutionary optimality principles to model the seasonal time course of LAI, which is often poorly simulated by complex ecosystem models.&lt;/p&gt;</jats:p>
-
Journal articleLavergne A, Harrison SP, Prentice IC, 2022,
Investigating C3/C4 plants competition using carbon isotopes and optimality principles
<jats:p>&lt;p&gt;Understanding the mechanisms underlying changes in carbon isotope discrimination (&amp;#916;&lt;sup&gt;13&lt;/sup&gt;C) in C&lt;sub&gt;3&lt;/sub&gt; and C&lt;sub&gt;4&lt;/sub&gt; plants is critical for predicting the C&lt;sub&gt;3&lt;/sub&gt;/C&lt;sub&gt;4&lt;/sub&gt; fraction in mixed ecosystems. Variations in &amp;#916;&lt;sup&gt;13&lt;/sup&gt;C are closely related to changes in the stomatal limitation of photosynthesis (i.e. the ratio of leaf internal to ambient partial pressure of CO&lt;sub&gt;2&lt;/sub&gt;, &lt;em&gt;c&lt;/em&gt;&lt;sub&gt;i&lt;/sub&gt;/&lt;em&gt;c&lt;/em&gt;&lt;sub&gt;a&lt;/sub&gt;), which are in turn determined by environmental variables, but also depend on the pathway of carbon assimilation. For instance, isotopic fractionation during the diffusion of CO&lt;sub&gt;2&lt;/sub&gt; through the stomata primarily influences &amp;#916;&lt;sup&gt;13&lt;/sup&gt;C in C&lt;sub&gt;4&lt;/sub&gt; plants, while fractionation during Rubisco carboxylation has a stronger imprint on &amp;#916;&lt;sup&gt;13&lt;/sup&gt;C in C&lt;sub&gt;3&lt;/sub&gt; plants. As a result, C&lt;sub&gt;3&lt;/sub&gt; plants are depleted in &lt;sup&gt;13&lt;/sup&gt;C compared to C&lt;sub&gt;4&lt;/sub&gt; plants. Isotopic measurements can thus be used as tracers of physiological processes in plants.&lt;/p&am
-
Journal articleMengoli G, Harrison SP, Prentice IC, 2022,
Towards a land surface model based on optimality principles
<jats:p>&lt;p&gt;Plants take up water from the soil via roots and release it into the atmosphere through stomata; uptake of CO&lt;sub&gt;2&lt;/sub&gt; from the atmosphere also proceeds through the stomata, implying tight coupling of transpiration and photosynthesis. We distinguish leaf-level (biochemical and stomatal) responses to external stimuli on different timescales: fast responses taking place over seconds to hours, and longer-term (acclimation) responses taking place over weeks to months. Typically, land-surface models (LSMs) have focused on the fast responses, and have not accounted for acclimation responses, although these can be different in magnitude and even in sign. We have developed a method that explicitly separates these two timescales in order to implement an existing optimality-based model, the P model, with a sub-daily timestep; and, thereby, to include acclimated responses within an LSM framework. The resulting model, compared to flux-tower gross primary production (GPP) data in five &amp;#8220;well-watered&amp;#8221; biomes from boreal to tropical, correctly reproduces diurnal cycles of GPP throughout the growing season. No changes of parameters are required between biomes, because optimality ensures that current parameter values are always adapted to the local environment. This is a clear practical advantage because it eliminates the need to specify different parameter values for different plant functional types. However, in areas with large seasonal variations in moisture variability, the model does not perform well. Here we address the issue of soil-moisture controls on GPP, which is a challenging issue for LSMs in general. We note two problems: an error in magnitude, and an error in shape. The model tends to overestimate GPP in dry areas because it does not consider the effect of low soil moisture (as opposed to atmospheric dryness) on photosynthesis; and it does not simul
This data is extracted from the Web of Science and reproduced under a licence from Thomson Reuters. You may not copy or re-distribute this data in whole or in part without the written consent of the Science business of Thomson Reuters.