Highest drought sensitivity and lowest resistance to growth suppression are found in the range core of the tree Fagus sylvatica L. not the equatorial range edge

Cavin L., Jump A.S. (2016) Highest drought sensitivity and lowest resistance to growth suppression are found in the range core of the tree Fagus sylvatica L. not the equatorial range edge. Global Change Biology. : 0-0.
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Doi: 10.1111/gcb.13366

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Biogeographical and ecological theory suggests that species distributions should be driven to higher altitudes and latitudes as global temperatures rise. Such changes occur as growth improves at the poleward edge of a species distribution and declines at the range edge in the opposite or equatorial direction, mirrored by changes in the establishment of new individuals. A substantial body of evidence demonstrates that such processes are underway for a wide variety of species. Case studies from populations at the equatorial range edge of a variety of woody species have led us to understand that widespread growth decline and distributional shifts are underway. However, in apparent contrast, other studies report high productivity and reproduction in some range edge populations. We sought to assess temporal trends in the growth of the widespread European beech tree (Fagus sylvatica) across its latitudinal range. We explored the stability of populations to major drought events and the implications for predicted widespread growth decline at its equatorial range edge. In contrast to expectations, we found greatest sensitivity and low resistance to drought in the core of the species range, whilst dry range edge populations showed particularly high resistance to drought and little evidence of drought-linked growth decline. We hypothesize that this high range edge resistance to drought is driven primarily by local environmental factors that allow relict populations to persist despite regionally unfavourable climate. The persistence of such populations demonstrates that range-edge decline is not ubiquitous and is likely to be driven by declining population density at the landscape scale rather than sudden and widespread range retraction. Copyright © 2016 John Wiley & Sons Ltd

Llegeix més

Community change and species richness reductions in rapidly advancing tree lines

Greenwood S., Chen J.-C., Chen C.-T., Jump A.S. (2016) Community change and species richness reductions in rapidly advancing tree lines. Journal of Biogeography. : 0-0.
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Doi: 10.1111/jbi.12776

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Aim: Climate change is causing shifts in the range of species worldwide. In high-altitude areas forests are often observed to be shifting their upper limits to higher altitudes in response to warming temperatures. Although this phenomenon is well described, the possible consequences of this for the wider forest community have not been fully considered. In this study, we used epiphytic macro-lichens to investigate the impacts of tree line advance on associated organisms. We hypothesized that the rate of forest advance should influence the species richness and composition of associated communities. Location: The Hehuanshan area, Central Mountain Range, Taiwan (24°08-09' N, 121°15 - 16' E). Methods: Lichen communities were sampled on trees occurring at 33 tree line sites displaying varying degrees of advance. Habitat variables were recorded. ANOVA, GLMM, nestedness analysis and indicator species analysis were used to investigate patterns of species richness and community composition and their association with tree line advance and habitat variables. Results: Species richness was lower in tree lines exhibiting rapid advance; reductions were related to tree size (considered here as a proxy for age) and the distance over which advance had occurred. Community composition varied with tree line form and forest position. Only a subset of species found in slowly advancing or stable forest edges occurred in rapidly advancing tree lines. Main conclusions: Differential migration rates between co-occurring species and differences in habitat structure associated with tree line advance can result in community change, but this depends, amongst other factors, on the speed of tree line advance. The importance of advance rate in determining the response suggests that reductions in species richness at tree line could be transitory. However, this will depend on whether advance continues, and on the changes in habitat associated with advance. Given the complexity of tree line behaviour, the findings that we report represent an essential step in understanding community responses to climate change. This understanding is of importance for biodiversity and conservation, especially given the high rate of endemism reported for this and other alpine regions. © 2016 John Wiley & Sons Ltd.

Llegeix més

Role of geographical provenance in the response of silver fir seedlings to experimental warming and drought

Matías, L., Gonzalez-Díaz, P., Quero, J.L., Camarero, J.J., Lloret, F., Jump, A.S. (2016) Role of geographical provenance in the response of silver fir seedlings to experimental warming and drought. Tree Physiology. 36: 1236-1246.
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Doi: 10.1093/treephys/tpw049

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Functional diversity underlies demographic responses to environmental variation in European forests

Ruiz-Benito, P., Ratcliffe, S., Jump, A.S., Gómez-Aparicio, L., Madrigal-González, J., Wirth, C., Kändler, G., Lehtonen, A., Dahlgren, J., Kattge, J., Zavala, M.A. (2016) Functional diversity underlies demographic responses to environmental variation in European forests. Global Ecology and Biogeography. : 0-0.
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Doi: 10.1111/geb.12515

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Gradual expansion of moisture sensitive Abies spectabilis forest in the Trans-Himalayan zone of central Nepal associated with climate change

Tiwari A., Fan Z.-X., Jump A.S., Li S.-F., Zhou Z.-K. (2016) Gradual expansion of moisture sensitive Abies spectabilis forest in the Trans-Himalayan zone of central Nepal associated with climate change. Dendrochronologia. : 0-0.
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Doi: 10.1016/j.dendro.2016.01.006

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Population structure and tree recruitment dynamics in the natural treeline ecotone of high mountains are strong indicators of vegetation responses to climate. Here, we examined recruitment dynamics of Abies spectabilis across the treeline ecotone (3439-3638. m asl) of Chimang Lekh of Annapurna Conservation Area in the Trans-Himalayan zone of central Nepal. Dendrochronological techniques were used to establish stand age structure by ring counts of adults, and by terminal bud scar count for seedlings and saplings. The results showed abundant seedling recruitment, higher regenerative inertia and colonization with a consistent range shift of the A. spectabilis treeline. The upward expansion of this sub-alpine treeline was found to be driven by a strong dependence of seedling recruitment and radial growth on snowmelt and precipitation as temperatures rise. The radial growth of A. spectabilis at the alpine timberline ecotone (ATE) and closed timberline forest (CTF) showed sensitivity to spring season (March-May) climate. Tree ring indices of CTF showed a strong positive correlation with spring and annual precipitation, and a significant negative correlation with spring and annual temperature, however, moisture sensitivity was less strong at ATE than CTF. © 2016 Elsevier GmbH.

Llegeix més

Evidence of current impact of climate change on life: A walk from genes to the biosphere

Penuelas J., Sardans J., Estiarte M., Ogaya R., Carnicer J., Coll M., Barbeta A., Rivas-Ubach A., Llusia J., Garbulsky M., Filella I., Jump A.S. (2013) Evidence of current impact of climate change on life: A walk from genes to the biosphere. Global Change Biology. 19: 2303-2338.
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Doi: 10.1111/gcb.12143

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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. © 2013 John Wiley & Sons Ltd.

Llegeix més

Summer season and long-term drought increase the richness of bacteria and fungi in the foliar phyllosphere of Quercus ilex in a mixed Mediterranean forest

Peñuelas J., Rico L., Ogaya R., Jump A.S., Terradas J. (2012) Summer season and long-term drought increase the richness of bacteria and fungi in the foliar phyllosphere of Quercus ilex in a mixed Mediterranean forest. Plant Biology. 14: 565-575.
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Doi: 10.1111/j.1438-8677.2011.00532.x

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We explored the changes in richness, diversity and evenness of epiphytic (on the leaf surface) and endophytic (within leaf tissues) bacteria and fungi in the foliar phyllosphere of Quercus ilex, the dominant tree species of Mediterranean forests. Bacteria and fungi were assessed during ontogenic development of the leaves, from the wet spring to the dry summer season in control plots and in plots subjected to drought conditions mimicking those projected for future decades. Our aim was to monitor succession in microbiota during the colonisation of plant leaves and its response to climate change. Ontogeny and seasonality exerted a strong influence on richness and diversity of the microbial phyllosphere community, which decreased in summer in the whole leaf and increased in summer in the epiphytic phyllosphere. Drought precluded the decrease in whole leaf phyllosphere diversity and increased the rise in the epiphytic phyllosphere. Both whole leaf bacterial and fungal richness decreased with the decrease in physiological activity and productivity of the summer season in control trees. As expected, the richness of epiphytic bacteria and fungi increased in summer after increasing time of colonisation. Under summer dry conditions, there was a positive relationship between TRF (terminal restriction fragments) richness and drought, both for whole leaf and epiphytic phyllosphere, and especially for fungal communities. These results demonstrate that changes in climate are likely to significantly alter microbial abundance and composition of the phyllosphere. Given the diverse functions and large number of phyllospheric microbes, the potential functional implications of such community shifts warrant exploration. © 2012 German Botanical Society and The Royal Botanical Society of the Netherlands.

Llegeix més

Reduced tree health and seedling production in fragmented Fagus sylvatica forest patches in the Montseny Mountains (NE Spain)

Barbeta A., Peñuelas J., Ogaya R., Jump A.S. (2011) Reduced tree health and seedling production in fragmented Fagus sylvatica forest patches in the Montseny Mountains (NE Spain). Forest Ecology and Management. 261: 2029-2037.
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Doi: 10.1016/j.foreco.2011.02.029

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Habitat fragmentation results in smaller and more isolated populations that may be at higher risk of extirpation or further decline in comparison with their more continuously distributed progenitors. Risks to fragmented populations have frequently been considered from the perspective of population genetics, however, disruption of normal plant demography may be an equal or greater threat to population persistence. We compared demographic performance and tree health in continuous and fragmented forest plots with similar tree size structure and local climatic and physiographic conditions in order to determine if fragments are characterized by poor health and reproduction. We found that beech forest fragments showed lower seedling density, more tree crown damage and also higher percentage of dead trees. However, mortality of juveniles in the youngest age class was substantially lower in fragments such that long-term population structure remained similar between the two forest types. If reduced mortality compensates for reduced seedling establishment, as our data suggest, then fragmented populations should show greater long-term persistence than would be predicted based on comparison of young age cohorts alone. However, despite such demographic compensation, the decreased health of adult trees may pose an increasing future threat to the fragmented populations. Our results demonstrate the importance of integrating demographic patterns over long time periods and not relying on single year or cohort comparisons and may partly explain population genetic differences previously reported for the same populations. © 2011 Elsevier B.V.

Llegeix més

Environmental change and the option value of genetic diversity

Jump A.S., Marchant R., Peñuelas J. (2009) Environmental change and the option value of genetic diversity. Trends in Plant Science. 14: 51-58.
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Doi: 10.1016/j.tplants.2008.10.002

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Rapid anthropogenic environmental change is altering selection pressures on natural plant populations. However, it is difficult to predict easily the novel selection pressures to which populations will be exposed. There is heavy reliance on plant genetic diversity for future crop security in agriculture and industry, but the implications of genetic diversity for natural populations receives less attention. Here, we examine the links between the genetic diversity of natural populations and aspects of plant performance and fitness. We argue that accumulating evidence demonstrates the future benefit or 'option value' of genetic diversity within natural populations when subject to anthropogenic environmental changes. Consequently, the loss of that diversity will hinder their ability to adapt to changing environments and is, therefore, of serious concern. Crown Copyright © 2008.

Llegeix més

The altitude-for-latitude disparity in the range retractions of woody species

Jump A.S., Mátyás C., Peñuelas J. (2009) The altitude-for-latitude disparity in the range retractions of woody species. Trends in Ecology and Evolution. 24: 694-701.
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Doi: 10.1016/j.tree.2009.06.007

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Increasing temperatures are driving rapid upward range shifts of species in mountains. An altitudinal range retreat of 10 m is predicted to translate into a ∼10-km latitudinal retreat based on the rate at which temperatures decline with increasing altitude and latitude, yet reports of latitudinal range retractions are sparse. Here, we examine potential climatic, biological, anthropogenic and methodological explanations for this disparity. We argue that the lack of reported latitudinal range retractions stems more from a lack of research effort, compounded by methodological difficulties, rather than from their absence. Given the predicted negative impacts of increasing temperatures on wide areas of the latitudinal distributions of species, the investigation of range retractions should become a priority in biogeographical research. © 2009 Elsevier Ltd. All rights reserved.

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