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1.
Glob Chang Biol ; 26(2): 322-324, 2020 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-31442346

RESUMEN

While we generally agree with Slette et al. (Global Change Biol, 2019), that ecologists 'should do better' when defining drought in ecological studies, we argue against the uncritical use of a standardized drought index (such as the Standardized Precipitation and Evapotranspiration Index, SPEI; Vicente-Serrano et al. J Climate, 23: 1696-1718, 2010), as a stand-alone criterium for quantifying and reporting drought conditions. Specifically, we raise the following issues: (a) standardization can lead to a misrepresentation of actual water supply, especially for moist climates; (b) standardized values are not directly comparable between different reference periods; and finally, (c) spatially coarsely resolved data sources are unlikely to represent site-level water supply. This article is a commentary on Slette et al., 25, 3193-3200; See also the response to this Letter to the Editor by Slette et al., 26, e1-e3.

2.
Ecol Lett ; 22(9): 1439-1448, 2019 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-31250529

RESUMEN

Species rear range edges are predicted to retract as climate warms, yet evidence of population persistence is accumulating. Accounting for this disparity is essential to enable prediction and planning for species' range retractions. At the Mediterranean edge of European beech-dominated temperate forest, we tested the hypothesis that individual performance should decline at the limit of the species' ecological tolerance in response to increased drought. We sampled 40 populations in a crossed factor design of geographical and ecological marginality and assessed tree growth resilience and decline in response to recent drought. Drought impacts occurred across the rear edge, but tree growth stability was unexpectedly high in geographically isolated marginal habitat and lower than anticipated in the species' continuous range and better-quality habitat. Our findings demonstrate that, at the rear edge, range shifts will be highly uneven and characterised by reduction in population density with local population retention rather than abrupt range retractions.


Asunto(s)
Sequías , Ecosistema , Fagus/crecimiento & desarrollo , Árboles/crecimiento & desarrollo , Cambio Climático , Bosques , Dinámica Poblacional , España
3.
Glob Chang Biol ; 25(5): 1549-1560, 2019 05.
Artículo en Inglés | MEDLINE | ID: mdl-30793443

RESUMEN

According to broad-scale application of biogeographical theory, widespread retractions of species' rear edges should be seen in response to ongoing climate change. This prediction rests on the assumption that rear edge populations are "marginal" since they occur at the limit of the species' ecological tolerance and are expected to decline in performance as climate warming pushes them to extirpation. However, conflicts between observations and predictions are increasingly accumulating and little progress has been made in explaining this disparity. We argue that a revision of the concept of marginality is necessary, together with explicit testing of population decline, which is increasingly possible as data availability improves. Such action should be based on taking the population perspective across a species' rear edge, encompassing the ecological, geographical and genetic dimensions of marginality. Refining our understanding of rear edge populations is essential to advance our ability to monitor, predict and plan for the impacts of environmental change on species range dynamics.


Asunto(s)
Cambio Climático , Extinción Biológica , Dinámica Poblacional , Animales , Ecología
4.
Glob Chang Biol ; 23(10): 4162-4176, 2017 10.
Artículo en Inglés | MEDLINE | ID: mdl-28418105

RESUMEN

Intense droughts combined with increased temperatures are one of the major threats to forest persistence in the 21st century. Despite the direct impact of climate change on forest growth and shifts in species abundance, the effect of altered demography on changes in the composition of functional traits is not well known. We sought to (1) quantify the recent changes in functional composition of European forests; (2) identify the relative importance of climate change, mean climate and forest development for changes in functional composition; and (3) analyse the roles of tree mortality and growth underlying any functional changes in different forest types. We quantified changes in functional composition from the 1980s to the 2000s across Europe by two dimensions of functional trait variation: the first dimension was mainly related to changes in leaf mass per area and wood density (partially related to the trait differences between angiosperms and gymnosperms), and the second dimension was related to changes in maximum tree height. Our results indicate that climate change and mean climatic effects strongly interacted with forest development and it was not possible to completely disentangle their effects. Where recent climate change was not too extreme, the patterns of functional change generally followed the expected patterns under secondary succession (e.g. towards late-successional short-statured hardwoods in Mediterranean forests and taller gymnosperms in boreal forests) and latitudinal gradients (e.g. larger proportion of gymnosperm-like strategies at low water availability in forests formerly dominated by broad-leaved deciduous species). Recent climate change generally favoured the dominance of angiosperm-like related traits under increased temperature and intense droughts. Our results show functional composition changes over relatively short time scales in European forests. These changes are largely determined by tree mortality, which should be further investigated and modelled to adequately predict the impacts of climate change on forest function.


Asunto(s)
Cambio Climático , Bosques , Árboles , Europa (Continente) , Dinámica Poblacional , Taiga
5.
Ecol Lett ; 20(4): 539-553, 2017 04.
Artículo en Inglés | MEDLINE | ID: mdl-28220612

RESUMEN

Drought events are increasing globally, and reports of consequent forest mortality are widespread. However, due to a lack of a quantitative global synthesis, it is still not clear whether drought-induced mortality rates differ among global biomes and whether functional traits influence the risk of drought-induced mortality. To address these uncertainties, we performed a global meta-analysis of 58 studies of drought-induced forest mortality. Mortality rates were modelled as a function of drought, temperature, biomes, phylogenetic and functional groups and functional traits. We identified a consistent global-scale response, where mortality increased with drought severity [log mortality (trees trees-1  year-1 ) increased 0.46 (95% CI = 0.2-0.7) with one SPEI unit drought intensity]. We found no significant differences in the magnitude of the response depending on forest biomes or between angiosperms and gymnosperms or evergreen and deciduous tree species. Functional traits explained some of the variation in drought responses between species (i.e. increased from 30 to 37% when wood density and specific leaf area were included). Tree species with denser wood and lower specific leaf area showed lower mortality responses. Our results illustrate the value of functional traits for understanding patterns of drought-induced tree mortality and suggest that mortality could become increasingly widespread in the future.


Asunto(s)
Sequías , Ecosistema , Árboles/fisiología , Longevidad , Hojas de la Planta/fisiología , Madera/fisiología
6.
Glob Chang Biol ; 23(10): 4106-4116, 2017 10.
Artículo en Inglés | MEDLINE | ID: mdl-28100041

RESUMEN

Ongoing changes in global climate are altering ecological conditions for many species. The consequences of such changes are typically most evident at the edge of a species' geographical distribution, where differences in growth or population dynamics may result in range expansions or contractions. Understanding population responses to different climatic drivers along wide latitudinal and altitudinal gradients is necessary in order to gain a better understanding of plant responses to ongoing increases in global temperature and drought severity. We selected Scots pine (Pinus sylvestris L.) as a model species to explore growth responses to climatic variability (seasonal temperature and precipitation) over the last century through dendrochronological methods. We developed linear models based on age, climate and previous growth to forecast growth trends up to year 2100 using climatic predictions. Populations were located at the treeline across a latitudinal gradient covering the northern, central and southernmost populations and across an altitudinal gradient at the southern edge of the distribution (treeline, medium and lower elevations). Radial growth was maximal at medium altitude and treeline of the southernmost populations. Temperature was the main factor controlling growth variability along the gradients, although the timing and strength of climatic variables affecting growth shifted with latitude and altitude. Predictive models forecast a general increase in Scots pine growth at treeline across the latitudinal distribution, with southern populations increasing growth up to year 2050, when it stabilizes. The highest responsiveness appeared at central latitude, and moderate growth increase is projected at the northern limit. Contrastingly, the model forecasted growth declines at lowland-southern populations, suggesting an upslope range displacement over the coming decades. Our results give insight into the geographical responses of tree species to climate change and demonstrate the importance of incorporating biogeographical variability into predictive models for an accurate prediction of species dynamics as climate changes.


Asunto(s)
Cambio Climático , Pinus sylvestris/crecimiento & desarrollo , Clima , Bosques , Geografía , Temperatura Ambiental , Árboles
7.
Glob Chang Biol ; 23(9): 3742-3757, 2017 09.
Artículo en Inglés | MEDLINE | ID: mdl-28135022

RESUMEN

Ongoing climate change poses significant threats to plant function and distribution. Increased temperatures and altered precipitation regimes amplify drought frequency and intensity, elevating plant stress and mortality. Large-scale forest mortality events will have far-reaching impacts on carbon and hydrological cycling, biodiversity, and ecosystem services. However, biogeographical theory and global vegetation models poorly represent recent forest die-off patterns. Furthermore, as trees are sessile and long-lived, their responses to climate extremes are substantially dependent on historical factors. We show that periods of favourable climatic and management conditions that facilitate abundant tree growth can lead to structural overshoot of aboveground tree biomass due to a subsequent temporal mismatch between water demand and availability. When environmental favourability declines, increases in water and temperature stress that are protracted, rapid, or both, drive a gradient of tree structural responses that can modify forest self-thinning relationships. Responses ranging from premature leaf senescence and partial canopy dieback to whole-tree mortality reduce canopy leaf area during the stress period and for a lagged recovery window thereafter. Such temporal mismatches of water requirements from availability can occur at local to regional scales throughout a species geographical range. As climate change projections predict large future fluctuations in both wet and dry conditions, we expect forests to become increasingly structurally mismatched to water availability and thus overbuilt during more stressful episodes. By accounting for the historical context of biomass development, our approach can explain previously problematic aspects of large-scale forest mortality, such as why it can occur throughout the range of a species and yet still be locally highly variable, and why some events seem readily attributable to an ongoing drought while others do not. This refined understanding can facilitate better projections of structural overshoot responses, enabling improved prediction of changes in forest distribution and function from regional to global scales.


Asunto(s)
Cambio Climático , Sequías , Árboles/crecimiento & desarrollo , Ecosistema , Bosques
8.
Glob Chang Biol ; 23(1): 362-379, 2017 01.
Artículo en Inglés | MEDLINE | ID: mdl-27298138

RESUMEN

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.


Asunto(s)
Cambio Climático , Sequías , Fagus/crecimiento & desarrollo , Clima , Fagus/fisiología , Densidad de Población , Árboles
9.
Tree Physiol ; 36(10): 1236-1246, 2016 10.
Artículo en Inglés | MEDLINE | ID: mdl-27273199

RESUMEN

Changes in climate can alter the distribution and population dynamics of tree species by altering their recruitment patterns, especially at range edges. However, geographical patterns of genetic diversity could buffer the negative consequences of changing climate at rear range edges where populations might also harbour individuals with drought-adapted genotypes. Silver fir (Abies alba Mill.) reaches its south-western distribution limit in the Spanish Pyrenees, where recent climatic dieback events have disproportionately affected westernmost populations. We hypothesized that silver fir populations from the eastern Pyrenees are less vulnerable to the expected changing climate due to the inclusion of drought-resistant genotypes. We performed an experiment under strictly controlled conditions simulating projected warming and drought compared with current conditions and analysed physiology, growth and survival of silver fir seedlings collected from eastern and western Pyrenean populations. Genetic analyses separated eastern and western provenances in two different lineages. Climate treatments affected seedling morphology and survival of both lineages in an overall similar way: elevated drought diminished survival and induced a higher biomass allocation to roots. Increased temperature and drought provoked more negative stem water potentials and increased δ13C ratios in leaves. Warming reduced nitrogen concentration and increased soluble sugar content in leaves, whereas drought increased nitrogen concentration. Lineage affected these physiological parameters, with western seedlings being more sensitive to warming and drought increase in terms of δ13C, nitrogen and content of soluble sugars. Our results demonstrate that, in A. alba, differences in the physiological response of this species to drought are also associated with differences in biogeographical history.


Asunto(s)
Abies/fisiología , Aclimatación , Sequías , Árboles/fisiología , Clima , Cambio Climático , Filogeografía , Plantones/fisiología , Temperatura Ambiental
10.
PLoS One ; 10(5): e0126581, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-25973854

RESUMEN

The modification of typical age-related growth by environmental changes is poorly understood, In part because there is a lack of consensus at individual tree level regarding age-dependent growth responses to climate warming as stands develop. To increase our current understanding about how multiple drivers of environmental change can modify growth responses as trees age we used tree ring data of a mountain subtropical pine species along an altitudinal gradient covering more than 2,200 m of altitude. We applied mixed-linear models to determine how absolute and relative age-dependent growth varies depending on stand development; and to quantify the relative importance of tree age and climate on individual tree growth responses. Tree age was the most important factor for tree growth in models parameterised using data from all forest developmental stages. Contrastingly, the relationship found between tree age and growth became non-significant in models parameterised using data corresponding to mature stages. These results suggest that although absolute tree growth can continuously increase along tree size when trees reach maturity age had no effect on growth. Tree growth was strongly reduced under increased annual temperature, leading to more constant age-related growth responses. Furthermore, young trees were the most sensitive to reductions in relative growth rates, but absolute growth was strongly reduced under increased temperature in old trees. Our results help to reconcile previous contrasting findings of age-related growth responses at the individual tree level, suggesting that the sign and magnitude of age-related growth responses vary with stand development. The different responses found to climate for absolute and relative growth rates suggest that young trees are particularly vulnerable under warming climate, but reduced absolute growth in old trees could alter the species' potential as a carbon sink in the future.


Asunto(s)
Cambio Climático , Pinus/crecimiento & desarrollo , Árboles/crecimiento & desarrollo , Altitud , Clima , Bosques
11.
Glob Chang Biol ; 21(2): 882-96, 2015 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-25044677

RESUMEN

Ongoing changes in global climate are altering ecological conditions for many species. The consequences of such changes are typically most evident at the edge of the geographical distribution of a species, where range expansions or contractions may occur. Current demographical status at geographical range limits can help us to predict population trends and their implications for the future distribution of the species. Thus, understanding the comparability of demographical patterns occurring along both altitudinal and latitudinal gradients would be highly informative. In this study, we analyse the differences in the demography of two woody species through altitudinal gradients at their southernmost distribution limit and the consistency of demographical patterns at the treeline across a latitudinal gradient covering the complete distribution range. We focus on Pinus sylvestris and Juniperus communis, assessing their demographical structure (density, age and mortality rate), growth, reproduction investment and damage from herbivory on 53 populations covering the upper, central and lower altitudes as well as the treeline at central latitude and northernmost and southernmost latitudinal distribution limits. For both species, populations at the lowermost altitude presented older age structure, higher mortality, decreased growth and lower reproduction when compared to the upper limit, indicating higher fitness at the treeline. This trend at the treeline was generally maintained through the latitudinal gradient, but with a decreased growth at the northern edge for both species and lower reproduction for P. sylvestris. However, altitudinal and latitudinal transects are not directly comparable as factors other than climate, including herbivore pressure or human management, must be taken into account if we are to understand how to infer latitudinal processes from altitudinal data.


Asunto(s)
Cambio Climático , Juniperus/fisiología , Pinus/fisiología , Dispersión de las Plantas , Altitud , Finlandia , Juniperus/crecimiento & desarrollo , Pinus/crecimiento & desarrollo , Reproducción , Escocia , España , Temperatura Ambiental
12.
Glob Chang Biol ; 20(12): 3756-66, 2014 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-25141823

RESUMEN

Altitudinal treelines are typically temperature limited such that increasing temperatures linked to global climate change are causing upslope shifts of treelines worldwide. While such elevational increases are readily predicted based on shifting isotherms, at the regional level the realized response is often much more complex, with topography and local environmental conditions playing an important modifying role. Here, we used repeated aerial photographs in combination with forest inventory data to investigate changes in treeline position in the Central Mountain Range of Taiwan over the last 60 years. A highly spatially variable upslope advance of treeline was identified in which topography is a major driver of both treeline form and advance. The changes in treeline position that we observed occurred alongside substantial increases in forest density, and lead to a large increase in overall forest area. These changes will have a significant impact on carbon stocking in the high altitude zone, while the concomitant decrease in alpine grassland area is likely to have negative implications for alpine species. The complex and spatially variable changes that we report highlight the necessity for considering local factors such as topography when attempting to predict species distributional responses to warming climate.


Asunto(s)
Altitud , Bosques , Modelos Biológicos , Temperatura Ambiental , Árboles/crecimiento & desarrollo , Secuestro de Carbono/fisiología , Simulación por Computador , Geografía , Densidad de Población , Taiwán
13.
J Exp Bot ; 65(1): 299-310, 2014 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-24220655

RESUMEN

Ongoing changes in global climate are having a significant impact on the distribution of plant species, with effects particularly evident at range limits. We assessed the capacity of Pinus sylvestris L. populations at northernmost and southernmost limits of the distribution to cope with projected changes in climate. We investigated responses including seed germination and early seedling growth and survival, using seeds from northernmost (Kevo, Finland) and southernmost (Granada, Spain) populations. Seeds were grown under current climate conditions in each area and under temperatures increased by 5 °C, with changes in precipitation of +30% or -30% with reference to current values at northern and southern limits, respectively, in a fully factorial controlled-conditions experimental design. Increased temperatures reduced germination time and enhanced biomass gain at both range edges but reduced survival at the southern range edge. Higher precipitation also increased survival and biomass but only under a southern climate. Seeds from the southern origin emerged faster, produced bigger seedlings, allocated higher biomass to roots, and survived better than northern ones. These results indicate that recruitment will be reduced at the southernmost range of the species, whereas it will be enhanced at the northern limit, and that the southern seed sources are better adapted to survive under drier conditions. However, future climate will impose a trade-off between seedling growth and survival probabilities. At the southern range edge, higher growth may render individuals more susceptible to mortality where greater aboveground biomass results in greater water loss through evapotranspiration.


Asunto(s)
Adaptación Fisiológica , Pinus sylvestris/fisiología , Biomasa , Cambio Climático , Demografía , Geografía , Germinación , Pinus sylvestris/crecimiento & desarrollo , Raíces de Plantas/crecimiento & desarrollo , Raíces de Plantas/fisiología , Brotes de la Planta/crecimiento & desarrollo , Brotes de la Planta/fisiología , Lluvia , Estaciones del Año , Plantones/crecimiento & desarrollo , Plantones/fisiología , Semillas/crecimiento & desarrollo , Semillas/fisiología , Suelo/química , Temperatura Ambiental , Factores de Tiempo , Agua/fisiología
14.
Biodivers Conserv ; 23(14): 3657-3671, 2014.
Artículo en Inglés | MEDLINE | ID: mdl-26321799

RESUMEN

Scientific studies reveal significant consequences of climate change for nature, from ecosystems to individual species. Such studies are important factors in policy decisions on forest conservation and management in Europe. However, while research has shown that climate change research start to impact on European conservation policies like Natura 2000, climate change information has yet to translate into management practices. This article contributes to the on-going debates about science-society relations and knowledge utilization by exploring and analysing the interface between scientific knowledge and forest management practice. We focus specifically on climate change debates in conservation policy and on how managers of forest areas in Europe perceive and use climate change ecology. Our findings show that forest managers do not necessarily deny the potential importance of climate change for their management practices, at least in the future, but have reservations about the current usefulness of available knowledge for their own areas and circumstances. This suggests that the science-management interface is not as politicized as current policy debates about climate change and that the use of climate change ecology is situated in practice. We conclude the article by discussing what forms of knowledge may enable responsible and future oriented management in practice focusing specifically on the role of reflexive experimentation and monitoring.

15.
Glob Chang Biol ; 19(8): 2303-38, 2013 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-23505157

RESUMEN

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.


Asunto(s)
Biota , Cambio Climático , Ecosistema , Invertebrados/fisiología , Fenómenos Fisiológicos de las Plantas , Vertebrados/fisiología , Adaptación Fisiológica , Animales , Evolución Biológica , Invertebrados/genética , Plantas/genética , Vertebrados/genética
16.
Mol Ecol ; 21(12): 2847-9; discussion 2850-1, 2012 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-22860246

RESUMEN

Predicted parallel impacts of habitat fragmentation on genes and species lie at the core of conservation biology, yet tests of this rule are rare. In a recent article in Ecology Letters, Struebig et al. (2011) report that declining genetic diversity accompanies declining species diversity in tropical forest fragments. However, this study estimates diversity in many populations through extrapolation from very small sample sizes. Using the data of this recent work, we show that results estimated from the smallest sample sizes drive the species-genetic diversity correlation (SGDC), owing to a false-positive association between habitat fragmentation and loss of genetic diversity. Small sample sizes are a persistent problem in habitat fragmentation studies, the results of which often do not fit simple theoretical models. It is essential, therefore, that data assessing the proposed SGDC are sufficient in order that conclusions be robust.


Asunto(s)
Ecosistema , Variación Genética , Sesgo , Conservación de los Recursos Naturales , Ambiente , Modelos Teóricos , Dinámica Poblacional , Tamaño de la Muestra
17.
Trends Plant Sci ; 16(1): 13-8, 2011 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-21050799

RESUMEN

Despite longstanding research, how anthropogenic disturbance affects the genetics of tree populations remains poorly understood. Although empirical evidence often conflicts with theoretical expectations, little progress has been made in refining experimental design or in reformulating theoretical hypotheses. Such progress is, however, essential to understand how forest tree species can tolerate anthropogenic disturbance. Further advances in forest fragmentation genetics research will require that processes driving reproduction and recruitment in fragmented populations are assessed from a tree's perspective instead of experimental convenience, using a multidisciplinary approach to explain the spatiotemporal dynamics of gene dispersal. In this opinion article we aim to inspire a new perspective in forest fragmentation genetics research.


Asunto(s)
Conservación de los Recursos Naturales , Ecosistema , Plantas/genética , Árboles/genética , Actividades Humanas
18.
J Environ Monit ; 12(10): 1791-8, 2010 Oct 06.
Artículo en Inglés | MEDLINE | ID: mdl-20818456

RESUMEN

Rising temperatures and increasing drought severity linked to global climate change are negatively impacting forest growth and function at the equatorial range edge of species distributions. Rapid dieback and range retractions are predicted to occur in many areas as temperatures continue to rise. Despite widespread negative impacts at the ecosystem level, equatorial range edges are not well studied, and their responses to climate change are poorly understood. Effective monitoring of tree responses to climate in these regions is of critical importance in order to predict and manage threats to populations. Remote sensing of impacts on forests can be combined with ground-based assessment of environmental and ecological changes to identify populations most at risk. Modelling may be useful as a 'first-filter' to identify populations of concern but, together with many remote sensing methods, often lacks adequate resolution for application at the range edge. A multidisciplinary approach, combining remote observation with targeted ground-based monitoring of local susceptible and resistant populations, is therefore required. Once at-risk regions have been identified, management can be adapted to reduce immediate risks in priority populations, and promote long-term adaptation to change. However, management to protect forest ecosystem function may be preferable where the maintenance of historical species assemblages is no longer viable.


Asunto(s)
Cambio Climático , Monitoreo del Ambiente , Árboles/fisiología , Conservación de los Recursos Naturales/métodos , Ecosistema , Modelos Teóricos
19.
Trends Ecol Evol ; 24(12): 694-701, 2009 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-19695735

RESUMEN

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 approximately 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.


Asunto(s)
Altitud , Temperatura Ambiental , Árboles/genética , Árboles/fisiología , Demografía , Calentamiento Global
20.
Trends Plant Sci ; 14(1): 51-8, 2009 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-19042147

RESUMEN

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.


Asunto(s)
Ambiente , Variación Genética , Plantas/genética , Selección Genética , Adaptación Biológica/genética , Productos Agrícolas/genética , Productos Agrícolas/crecimiento & desarrollo , Ecosistema , Efecto Invernadero , Inmunidad Innata , Desarrollo de la Planta , Enfermedades de las Plantas/genética , Dinámica Poblacional
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