Lamb A.M., Gan H.M., Greening C., Joseph L., Lee Y., Morán-Ordóñez A., Sunnucks P., Pavlova A. (2018) Climate-driven mitochondrial selection: A test in Australian songbirds. Molecular Ecology. 27: 898-918.LinkDoi: 10.1111/mec.14488
Diversifying selection between populations that inhabit different environments can promote lineage divergence within species and ultimately drive speciation. The mitochondrial genome (mitogenome) encodes essential proteins of the oxidative phosphorylation (OXPHOS) system and can be a strong target for climate-driven selection (i.e., associated with inhabiting different climates). We investigated whether Pleistocene climate changes drove mitochondrial selection and evolution within Australian birds. First, using phylogeographic analyses of the mitochondrial ND2 gene for 17 songbird species, we identified mitochondrial clades (mitolineages). Second, using distance-based redundancy analyses, we tested whether climate predicts variation in intraspecific genetic divergence beyond that explained by geographic distances and geographic position. Third, we analysed 41 complete mitogenome sequences representing each mitolineage of 17 species using codon models in a phylogenetic framework and a biochemical approach to identify signals of selection on OXPHOS protein-coding genes and test for parallel selection in mitolineages of different species existing in similar climates. Of 17 species examined, 13 had multiple mitolineages (range: 2–6). Climate was a significant predictor of mitochondrial variation in eight species. At least two amino acid replacements in OXPHOS complex I could have evolved under positive selection in specific mitolineages of two species. Protein homology modelling showed one of these to be in the loop region of the ND6 protein channel and the other in the functionally critical helix HL region of ND5. These findings call for direct tests of the functional and evolutionary significance of mitochondrial protein candidates for climate-associated selection. © 2018 John Wiley & Sons Ltd
Le Quéré C., Andrew R.M., Friedlingstein P., Sitch S., Pongratz J., Manning A.C., Ivar Korsbakken J., Peters G.P., Canadell J.G., Jackson R.B., Boden T.A., Tans P.P., Andrews O.D., Arora V.K., Bakker D.C.E., Barbero L., Becker M., Betts R.A., Bopp L., Chevallier F., Chini L.P., Ciais P., Cosca C.E., Cross J., Currie K., Gasser T., Harris I., Hauck J., Haverd V., Houghton R.A., Hunt C.W., Hurtt G., Ilyina T., Jain A.K., Kato E., Kautz M., Keeling R.F., Klein Goldewijk K., Körtzinger A., Landschützer P., Lefèvre N., Lenton A., Lienert S., Lima I., Lombardozzi D., Metzl N., Millero F., Monteiro P.M.S., Munro D.R., Nabel J.E.M.S., Nakaoka S.-I., Nojiri Y., Antonio Padin X., Peregon A., Pfeil B., Pierrot D., Poulter B., Rehder G., Reimer J., Rödenbeck C., Schwinger J., Séférian R., Skjelvan I., Stocker B.D., Tian H., Tilbrook B., Tubiello F.N., Laan-Luijkx I.T.V., Werf G.R.V., Van Heuven S., Viovy N., Vuichard N., Walker A.P., Watson A.J., Wiltshire A.J., Zaehle S., Zhu D. (2018) Global Carbon Budget 2017. Earth System Science Data. 10: 405-448.LinkDoi: 10.5194/essd-10-405-2018
Accurate assessment of anthropogenic carbon dioxide (CO2) emissions and their redistribution among the atmosphere, ocean, and terrestrial biosphere-the "global carbon budget"-is important to better understand the global carbon cycle, support the development of climate policies, and project future climate change. Here we describe data sets and methodology to quantify the five major components of the global carbon budget and their uncertainties. CO2 emissions from fossil fuels and industry (EFF) are based on energy statistics and cement production data, respectively, while emissions from land-use change (ELUC), mainly deforestation, are based on land-cover change data and bookkeeping models. The global atmospheric CO2 concentration is measured directly and its rate of growth (GATM) is computed from the annual changes in concentration. The ocean CO2 sink (SOCEAN) and terrestrial CO2 sink (SLAND) are estimated with global process models constrained by observations. The resulting carbon budget imbalance (BIM), the difference between the estimated total emissions and the estimated changes in the atmosphere, ocean, and terrestrial biosphere, is a measure of imperfect data and understanding of the contemporary carbon cycle. All uncertainties are reported as ±1δ. For the last decade available (2007-2016), EFF was 9.4±0.5 GtC yr-1, ELUC 1.3±0.7 GtC yr-1, GATM 4.7±0.1 GtC yr-1, SOCEAN 2.4±0.5 GtC yr-1, and SLAND 3.0±0.8 GtC yr-1, with a budget imbalance BIM of 0.6 GtC yr-1 indicating overestimated emissions and/or underestimated sinks. For year 2016 alone, the growth in EFF was approximately zero and emissions remained at 9.9±0.5 GtC yr-1. Also for 2016, ELUC was 1.3±0.7 GtC yr-1, GATM was 6.1±0.2 GtC yr-1, SOCEAN was 2.6±0.5 GtC yr-1, and SLAND was 2.7±1.0 GtC yr-1, with a small BIM of-0.3 GtC. GATM continued to be higher in 2016 compared to the past decade (2007-2016), reflecting in part the high fossil emissions and the small SLAND consistent with El Ninõ conditions. The global atmospheric CO2 concentration reached 402.8±0.1 ppm averaged over 2016. For 2017, preliminary data for the first 6-9 months indicate a renewed growth in EFF of C2.0% (range of 0.8 to 3.0 %) based on national emissions projections for China, USA, and India, and projections of gross domestic product (GDP) corrected for recent changes in the carbon intensity of the economy for the rest of the world. This living data update documents changes in the methods and data sets used in this new global carbon budget compared with previous publications of this data set (Le Quéré et al., 2016, 2015b, a, 2014, 2013). All results presented here can be downloaded from https://doi.org/10.18160/GCP-2017 (GCP, 2017). © 2018 Author(s).
Leal I.R., Ribeiro-Neto J.D., Arnan X., Oliveira F.M.P., Arcoverde G.B., Feitosa R.M., Andersen A.N. (2018) Ants of the Caatinga: Diversity, biogeography, and functional responses to anthropogenic disturbance and climate change. Caatinga: The Largest Tropical Dry Forest Region in South America. : 65-95.LinkDoi: 10.1007/978-3-319-68339-3_3
Despite the outstanding diversity and ecological relevance of ants in most terrestrial ecosystems, current knowledge of the ants of the Caatinga is still incipient. This chapter offers an overview covering the diversity, taxonomy, biogeography, and functional composition of the Caatinga ant fauna, and a synthesis on ant response to chronic anthropogenic disturbance and increased aridity. We compiled a database consisting of 572 presence-absence ant records and 276 ant species from 37 localities in the Caatinga. As expected, most of the Caatinga has not been intensively sampled for ants, with the intensive sampling that has been conducted revealing high rates of species turnover across localities. Most ant species recorded in the Caatinga are widely distributed in other biomes, especially in Cerrado, and few species can be considered endemic to the Caatinga. Thus, the Caatinga ant fauna appears to represent an impoverished subset of the Cerrado's fauna. Such a reduced endemism and the occurrence of a highly depauperate ant fauna at a regional level contrast to the diversity patterns exhibited by the Caatinga flora and other faunal groups. Significant changes in ant taxonomic and functional composition in response to human disturbance are observed, with a predictable winner-loser replacement. Disturbance winners consist of generalist species exhibiting wide environmental tolerances and those inhabiting open habitats (Opportunists and Dominant Dolichoderinae). Highly specialized species are disturbance losers (Specialist predators). Aridity also affects both species occurrence and functional-group composition of local assemblages. Since several ant species and functional groups are sensitive to increasing disturbance and aridity, ant-mediated ecological services are already threatened in the Caatinga biota. © Springer International Publishing AG 2017.
Lecina-Diaz J., Alvarez A., Regos A., Drapeau P., Paquette A., Messier C., Retana J. (2018) The positive carbon stocks–biodiversity relationship in forests: co-occurrence and drivers across five subclimates. Ecological Applications. 28: 1481-1493.LinkDoi: 10.1002/eap.1749
Carbon storage in forests and its ability to offset global greenhouse gas emissions, as well as biodiversity and its capacity to support ecosystem functions and services, are often considered separately in landscape planning. However, the potential synergies between them are currently poorly understood. Identifying the spatial patterns and factors driving their co-occurrence across different climatic zones is critical to more effectively conserve forest ecosystems at the regional level. Here, we integrated information of National Forest Inventories and Breeding Bird Atlases across Europe and North America (Spain and Quebec, respectively), covering five subclimates (steppe, dry Mediterranean, humid Mediterranean, boreal, and temperate). In particular, this study aimed to (1) determine the spatial patterns of both forest carbon stocks and biodiversity (bird richness, tree richness, and overall biodiversity) and the factors that influence them; (2) establish the relationships between forest carbon stocks and biodiversity; and (3) define and characterize the areas of high (hotspots) and low (coldspots) values of carbon and biodiversity, and ultimately quantify their spatial overlap. Our results show that the factors affecting carbon and biodiversity vary between regions and subclimates. The highest values of carbon and biodiversity were found in northern Spain (humid Mediterranean subclimate) and southern Quebec (temperate subclimate) where there was more carbon as climate conditions were less limiting. High density and structural diversity simultaneously favored carbon stocks, tree, and overall biodiversity, especially in isolated and mountainous areas, often associated with steeper slopes and low accessibility. In addition, the relationship between carbon stocks and biodiversity was positive in both regions and all subclimates, being stronger where climate is a limiting factor for forest growth. The spatial overlap between hotspots of carbon and biodiversity provides an excellent opportunity for landscape planning to maintain carbon stocks and conserve biodiversity. The variables positively affecting carbon and biodiversity were also driving the hotspots of both carbon and biodiversity, emphasizing the viability of “win-win” solutions. Our results highlight the need to jointly determine the spatial patterns of ecosystem services and biodiversity for an effective and sustainable planning of forest landscapes that simultaneously support conservation and mitigate climate change. © 2018 by the Ecological Society of America
Ledo, A., Paul, K.I., Burslem, D.F.R.P., Ewel, J.J., Barton, C., Battaglia, M., Brooksbank, K., Carter, J., Eid, T.H., England, J.R., Fitzgerald, A., Jonson, J., Mencuccini, M., Montagu, K.D., Montero, G., Mugasha, W.A., Pinkard, E., Roxburgh, S., Ryan, C.M., Ruiz-Peinado, R., Sochacki, S., Specht, A., Wildy, D., Wirth, C., Zerihun, A., Chave, J. (2018) Tree size and climatic water deficit control root to shoot ratio in individual trees globally. New Phytologist. 217: 8-11.LinkDoi: 10.1111/nph.14863
Lequy E., Avila A., Boudiaf Nait Kaci M., Turpault M.-P. (2018) Atmospheric deposition of particulate matter between Algeria and France: Contribution of long and short-term sources. Atmospheric Environment. 191: 181-193.LinkDoi: 10.1016/j.atmosenv.2018.08.013
Large worldwide sources of dust, such as the Saharan desert, play a key role in the amounts and composition of atmospheric particulate deposition (APD), but their relative contribution compared to other sources remain unclear. Our study aimed to apportion Saharan, regional, and anthropogenic sources of APD in three sampling along a long transect affected by Saharan outbreaks. We quantified total APD, and analyzed its mineralogical and chemical composition between 2011 and 2012.. Strong markers of Saharan dust, such as large amounts of APD and of a low Al2O3:CaO ratio allowed identifying clear periods influenced by Saharan outbreaks. Nitrogen and phosphorus reflected soil affected by agricultural practices, while Cd, Pb, Sb and Sn tracked traffic and industrial sources – as confirmed by enrichment factors. Then, we designed a conceptual model including sensitivity analyses to estimate the contribution of unanalyzed (10–11%, likely chlorites or sulfates), organic (34–41%), anthropogenic (11–22%), mineral-regional (5–25%) and mineral-Saharan (10–38%) matter over our entire study period. Our study shows the rapidly decreasing contribution of Saharan outbreaks – and the decreasing flux of Ca and Mg, from 40 to 0.4 kg.ha−1 over the study period between Algeria and France. Yet, Saharan outbreaks were still noticeable in APD at a site 1500 km away. Our study also shows the large relative contribution of organic and anthropogenic sources to APD in the three sampling sites, and their possible influence on nutrient budgets. © 2018 Elsevier Ltd
Leslie, A.D., Mencuccini, M., Perks, M.P. (2018) Preliminary growth functions for Eucalyptus gunnii in the UK. Biomass and Bioenergy. 108: 464-469.LinkDoi: 10.1016/j.biombioe.2017.10.037
Liu D., Ogaya R., Barbeta A., Yang X., Peñuelas J. (2018) Long-term experimental drought combined with natural extremes accelerate vegetation shift in a Mediterranean holm oak forest. Environmental and Experimental Botany. 151: 1-11.LinkDoi: 10.1016/j.envexpbot.2018.02.008
Increasing drought combined with natural extremes are expected to accelerate forest die-off and shifts in vegetation in the Mediterranean Basin. However, fewer studies have explored these climate-driven changes in forest ecosystems. A long-term (17-year) experimental drought (−30% precipitation) was established in a Mediterranean holm oak forest with high (H) and low (L) canopies to determine the changes in stem mortality, recruitment and composition shifts. Experimental drought increased annual stem mortality rate at the community level for both H- and L-canopies. Natural drought amplified the effects of experimental drought on stem mortality at the community level and of Q. ilex for H- and L-canopies. The timescales of natural drought, however, varied substantially with canopy types and species, with shorter timescales in L- than H-canopy and for Q. ilex than P. latifolia. Furthermore, experimental drought combined with natural extremes amplified the increases in stem mortality and decreases in growth for L-canopy. Contrasting responses between Q. ilex and P. latifolia for the relative in abundance and growth were observed in L-canopy and drought treatment reinforced the vegetation shift favoring P. latifolia. These findings suggest continuous drought regimes accelerated a vegetation shift, implying potential consequences for the functions and services for water-limited forest ecosystems. © 2018 Elsevier B.V.
Liu D., Piao S., Wang T., Wang X., Wang X., Ding J., Ciais P., Peñuelas J., Janssens I. (2018) Decelerating Autumn CO2 Release With Warming Induced by Attenuated Temperature Dependence of Respiration in Northern Ecosystems. Geophysical Research Letters. 45: 5562-5571.LinkDoi: 10.1029/2018GL077447
Feedbacks from the carbon cycle in boreal and arctic ecosystems can significantly affect climate change, but the effects of climate change on the high-latitude carbon cycle during the dormant period remain uncertain. By analyzing the long-term atmospheric CO2 concentration record from Point Barrow in Alaska, we show that warming significantly boosts net CO2 release in autumn over the period 1974–2014. But this warming-stimulated effect has been attenuated since 1997. This deceleration of net CO2 release with warming is ascribed to the attenuation in respiration response to temperature rather than changing relationship between temperature and productivity or changes in atmospheric transport, fossil fuel emissions, or air-sea CO2 exchanges. The attenuated respiration response is likely due to decoupling between temperature and plant-derived carbon inputs to soil for decomposition. Contrary to previous suggestions, warming no longer results in a higher autumn net CO2 release. ©2018. American Geophysical Union. All Rights Reserved.
Liu, Q., Piao, S., Janssens, I.A., Fu, Y., Peng, S., Lian, X., Ciais, P., Myneni, R.B., Peñuelas, J., Wang, T. (2018) Extension of the growing season increases vegetation exposure to frost. Nature Communications. 9: 0-0.LinkDoi: 10.1038/s41467-017-02690-y
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