Increased eutrophication and nutrient imbalances in the agricultural soils of NE Catalonia (Spain) during the last four decades.

Peñuelas J, Sardans J, Alcañiz JM, Poch JM (2009) Increased eutrophication and nutrient imbalances in the agricultural soils of NE Catalonia (Spain) during the last four decades. Journal of Environmental Biology 30: 841-846.

Influence of plant productivity over variability of soil respiration: a multi-scale approach.

Curiel J, Janssens I, Bahn M, Longdoz B, Baldocchi DD, Misson L, Davidson EA, Luyssaert S, Peñuelas J, Mencuccini M, Acosta M, Arrigan N, Aubinet JM, Carrara A, Gimeno C, Gruenwald T, Inglima I, Ma S, Montagnani L, Moyano F, Pavelka M et al. (2009) Influence of plant productivity over variability of soil respiration: a multi-scale approach. Geophys. Res. Abstr. 11, EGU2009-10349.

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.
Enllaç
Doi: 10.1016/j.tplants.2008.10.002

Resum:

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.

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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.
Enllaç
Doi: 10.1016/j.tree.2009.06.007

Resum:

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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Microspatial population genetic structure of the Mediterranean shrub Fumana thymifolia

Jump A.S., Rico L., Lloret F., Peñuelas J. (2009) Microspatial population genetic structure of the Mediterranean shrub Fumana thymifolia. Plant Biology. 11: 152-160.
Enllaç
Doi: 10.1111/j.1438-8677.2008.00109.x

Resum:

Fumana thymifolia (Cistaceae) is an insect-pollinated, gravity-dispersed evergreen shrub, which is a common component of fire-prone Mediterranean shrubland ecosystems. Despite the availability of basic knowledge on its ecology, little is known of its breeding system and no information is available on its population genetic structure. We explored the within-population genetic structure of this species using amplified fragment length polymorphism (AFLP) molecular markers and related this to predictions based on its breeding system, pollen and seed dispersal. Existing information on the reproductive ecology of F. thymifolia was supplemented by artificial pollination experiments. We determined that self-fertilisation can occur in F. thymifolia but results in reduced fruit set. Significant genetic structuring was detected within the population, a likely consequence of localised seed dispersal in combination with a mixed mating system. In a study site covering approximately 0.5 ha, amova revealed that approximately 9% of genetic variability was distributed among population subsamples. Significant spatial genetic structure was detected, with kinship coefficients being significantly elevated above the null expectation in the first six distance classes (maximum 5 m), and a value of Sp of up to 0.0342, comparable with species having similar ecological characteristics. Weak isolation by distance at the plot scale was detected, suggesting that insect-mediated pollen flow is non-random, despite being more extensive than seed dispersal. Fumana thymifolia provides a promising model for the investigation of both short- and long-term population dynamics in relation to fire frequency within this plant community. © 2008 German Botanical Society and The Royal Botanical Society of the Netherlands.

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Seasonality of monoterpene emission potentials in quercus ilex and pinus pinea: Implications for regional VOC emissions modeling

Keenan T., Ülo N., Sabate S., Gracia C., Pẽuelas J. (2009) Seasonality of monoterpene emission potentials in quercus ilex and pinus pinea: Implications for regional VOC emissions modeling. Journal of Geophysical Research Atmospheres. 114: 0-0.
Enllaç
Doi: 10.1029/2009JDO11904

Resum:

VOC emissions from terrestrial ecosystems provide one of the principal controls over oxidative photochemistry in the lower atmosphere and the resulting air pollution. Such atmospheric processes have strong seasonal cycles. Although similar seasonal cycles in VOC emissions from terrestrial ecosystems have been reported, regional emissions inventories generally omit the effect of seasonality on emissions. We compiled measurement data on seasonal variations in monoterpene emissions potentials for two evergreen species (Quercus ilex and Pinus pinea) and used these data to construct two contrasting seasonal response functions for the inclusion in monoterpene emission models. We included these responses in the Niinemets et al. model and compared simulation results to those of the MEGAN model, both with and without its predicted seasonality. The effect of seasonality on regional monoterpene emissions inventories for European Mediterranean forests dominated by these species was tested for both models, using the GOTILWA+ biosphere model platform. The consideration of seasonality in the Niinemets et al. model reduced total estimated annual monoterpene emissions by up to 65% in some regions, with largest reductions at lower latitudes. The MEGAN model demonstrated a much weaker seasonal response than that in the Niinemets et al. model, and did not capture the between species seasonality differences found in this study. Results suggest that previous regional model inventories based on one fixed emission factor likely overestimate regional emissions, and species-specific expressions of seasonality may be necessary. The consideration of seasonality both largely reduces monoterpene emissions estimates, and changes their expected seasonal distribution. Copyright 2009 by the American Geophysical Union.

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Airborne trace element pollution in 11 European cities assessed by exposure of standardised ryegrass cultures

Klumpp A., Ansel W., Klumpp G., Breuer J., Vergne P., Sanz M.J., Rasmussen S., Ro-Poulsen H., Ribas Artola A., Peñuelas J., He S., Garrec J.P., Calatayud V. (2009) Airborne trace element pollution in 11 European cities assessed by exposure of standardised ryegrass cultures. Atmospheric Environment. 43: 329-339.
Enllaç
Doi: 10.1016/j.atmosenv.2008.09.040

Resum:

Within a European biomonitoring programme, Italian ryegrass (Lolium multiflorum Lam.) was employed as accumulative bioindicator of airborne trace elements (As, Cd, Cr, Cu, Fe, Ni, Pb, Sb, V, Zn) in urban agglomerations. Applying a highly standardised method, grass cultures were exposed for consecutive periods of four weeks each to ambient air at up to 100 sites in 11 cities during 2000-2002. Results of the 2001 exposure experiments revealed a clear differentiation of trace element pollution within and among local monitoring networks. Pollution was influenced particularly by traffic emissions. Especially Sb, Pb, Cr, Fe, and Cu exhibited a very uneven distribution within the municipal areas with strong accumulation in plants from traffic-exposed sites in the city centres and close to major roads, and moderate to low levels in plants exposed at suburban or rural sites. Accumulation of Ni and V was influenced by other emission sources. The biomonitoring sites located in Spanish city centres featured a much higher pollution load by trace elements than those in other cities of the network, confirming previously reported findings obtained by chemical analyses of dust deposition and aerosols. At some heavily-trafficked sites, legal thresholds for Cu, Pb, and V contents in foodstuff and animal feed were reached or even surpassed. The study confirmed that the standardised grass exposure is a useful and reliable tool to monitor and to assess environmental levels of potentially toxic compounds of particulate matter. © 2008 Elsevier Ltd. All rights reserved.

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Determinants of local ant (Hymenoptera: Formicidae) species richness and activity density across Europe

Kumschick S., Schmidt-Entling M.H., Bacher S., Hickler T., Espadaler X., Nentwig W. (2009) Determinants of local ant (Hymenoptera: Formicidae) species richness and activity density across Europe. Ecological Entomology. 34: 748-754.
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Doi: 10.1111/j.1365-2311.2009.01127.x

Resum:

1. Species richness is influenced by local habitat features and large-scale climatic gradients. Usually, both influences are studied in isolation because of the divergent spatial scales at which they occur. Here, we compared the influence of large-scale climate and local habitat type on European ants using a continent-wide, standardised sampling programme. 2. We investigated species richness and activity density from pitfall traps distributed over four habitat types at 17 locations from northern Sweden to Spain and Greece. Species richness and activity density were analysed with respect to ambient energy [equilibrium evapotranspiration (EET)] and productive energy (net primary productivity). Furthermore, we compared ant richness and activity density between the four habitat types: arable land, scrubland, grassland, and forest. 3. Species richness and activity density of ants increased with equilibrium evapotranspiration (EET), explaining 30.2% of the total variation in species richness and 24.2% of activity density. Habitat type explained an additional 19.2% of the variation in species richness and 20.2% of activity density, and was not related to productivity. Species richness and activity density were highest in scrubland and significantly lower in forest and (marginally significant) in arable land. 4. The increase in EET and the decrease in forest confirms the pronounced thermophily of ants, whereas the decrease in arable land is probably caused by soil disturbance. © 2009 The Royal Entomological Society.

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Extinction debt: a challenge for biodiversity conservation

Kuussaari M., Bommarco R., Heikkinen R.K., Helm A., Krauss J., Lindborg R., Öckinger E., Pärtel M., Pino J., Rodà F., Stefanescu C., Teder T., Zobel M., Steffan-Dewenter I. (2009) Extinction debt: a challenge for biodiversity conservation. Trends in Ecology and Evolution. 24: 564-571.
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Doi: 10.1016/j.tree.2009.04.011

Resum:

Local extinction of species can occur with a substantial delay following habitat loss or degradation. Accumulating evidence suggests that such extinction debts pose a significant but often unrecognized challenge for biodiversity conservation across a wide range of taxa and ecosystems. Species with long generation times and populations near their extinction threshold are most likely to have an extinction debt. However, as long as a species that is predicted to become extinct still persists, there is time for conservation measures such as habitat restoration and landscape management. Standardized long-term monitoring, more high-quality empirical studies on different taxa and ecosystems and further development of analytical methods will help to better quantify extinction debt and protect biodiversity. © 2009 Elsevier Ltd. All rights reserved.

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Patterns of species impoverishment in managed forests of Catalonia (NE Spain)

Lioret F., Solé A., Pino J., Vayreda J., Font X., Terradas J. (2009) Patterns of species impoverishment in managed forests of Catalonia (NE Spain). Journal of Vegetation Science. 20: 675-685.
Enllaç
Doi: 10.1111/j.1654-1103.2009.01059.x

Resum:

Question: In managed forests, woody plant richness shows great variations in pattern. Herein we try to elucidate the role of major factors, such as successional status, to explain this variation. Assuming that less competitive or disturbance-sensitive species will be systematically more prone to disappear, we investigate the existence of nonrandom patterns of species impoverishment - i.e., the number of species unable to attain maximal richness and the ecological and successional status of species associated with impoverishment in relation to a regional climatic gradient. Methods: We explored species composition in approximately 7500 forest plots in Catalonia (NE Spain). We evaluated non-random patterns of species impoverishment by analyzing their nestedness. Multivariate analysis was used to relate environmental variables and impoverishment to species occurrence. Plot successional status and ecological range were also estimated from species composition, and species impoverishment was then correlated to these estimators. Results: Most forests show a non-random pattern of species loss: poor stands tend to retain the same species, and the species determining high richness tend to be the same. Late successional species tend to be more common in impoverished plots of drier and warmer forests, while species typical of open or disturbed habitats are more common in impoverished plots of moister and colder forests. Communities dominated by early or late successional species are mostly impoverished, while the richest stands are constituted by species of intermediate stages. Forests dominated by species with a narrow or wide ecological range showed high impoverishment levels, while the richest stands had species with an intermediate ecological range. Discussion: In warmer Mediterranean forests, impoverishment tends to be associated with late successional stages, while in moister and colder forests, species loss is more closely related to disturbance and exploitation. This study reveals the difficulties involved in using species richness as a simple descriptor of the degree of forest conservation. Identification of dominant species and species indicative of ecological processes would constitute an easily applicable practice that would consolidate assessment of forests status. © 2009 International Association for Vegetation Science.

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