Interactions between transplants of Phragmites australis and Juncus acutus in Mediterranean coastal marshes: The modulating role of environmental gradients

Batriu E., Ninot J.M., Pino J. (2015) Interactions between transplants of Phragmites australis and Juncus acutus in Mediterranean coastal marshes: The modulating role of environmental gradients. Aquatic Botany. 124: 29-38.
Enllaç
Doi: 10.1016/j.aquabot.2015.03.003

Resum:

Interactions between two coastal marsh plants (Phragmites australis and Juncus acutus) were investigated along three natural gradients of salinity, water table and soil texture, variously combined in a microtidal Mediterranean coastal marsh. Our aim was to clarify to what extent plant interactions explain the occurrence of stands of both species, since they are not solely due to their tolerance to environmental conditions. We used a replacement series design of field transplants. Mortality and relative yield index of aerial biomass were analyzed to assess the outcome of interactions using Generalized Linear Mixed Models. Results show that mortality was entirely driven by natural gradients. Specifically, higher salinity and soil clay contents increased mortality in both species, whereas high water table increased survival only in P. australis. Growth was controlled by plant interactions and by natural gradients. According to these results P. australis can suppress J. acutus in waterlogged and non-saline conditions. Where water table is deeper, J. acutus can suppress P. australis along a wide range of saline conditions. In the driest situations both species exhibited mutual interference and, in some cases, P. australis can again suppress J. acutus. Facilitation occurred along the salinity gradient in situations that correspond to low, medium or high stress for the beneficiary species, pointing that exceptions to the stress gradient hypothesis may occur in systems including multiple stress gradients. Our results suggest that competitive interactions and environmental gradients are not fully responsible for plant distribution in microtidal coastal marshes. © 2015 Elsevier B.V.

Llegeix més

Filtering of plant functional traits is determined by environmental gradients and by past land use in a mediterranean coastal marsh

Batriu E., Ninot J.M., Pino J. (2015) Filtering of plant functional traits is determined by environmental gradients and by past land use in a mediterranean coastal marsh. Journal of Vegetation Science. 26: 492-500.
Enllaç
Doi: 10.1111/jvs.12251

Resum:

Question: What is the effect of past land use and environmental gradients on plant functional traits within coastal marsh plant communities? Location: Mediterranean microtidal marshes in the Llobregat Delta, NE Spain. Methods: We used a data set collected previously comprising 45 vegetation plots with associated soil parameters, water table conditions and past land use. For each species we obtained the values or states for a set of plant functional traits: plant height, leaf dry matter content, specific leaf area, seed production, seed weight, life form and lateral expansion. To account for the effect of phylogeny, we evaluated trait diversity skewness by means of an ultrametric phylogenetic tree specifically constructed for the species studied. The association between both environmental gradients and past disturbance, and plant functional traits was tested by means of RLQ analysis. Results: Of all the traits, only seed weight showed a phylogenetic signal; consequently, phylogeny was not included in the RLQ analysis. Conductivity was negatively correlated with seed weight, whereas water table conditions and soil ionic balance were negatively correlated with specific leaf area. Past disturbance was negatively correlated with leaf dry matter content and with lateral expansion. Conclusions: Plant traits of Llobregat Delta coastal marsh communities are conditioned by environmental gradients and by past land use. Soil ionic balance and water table conditions determine key plant functional traits such as specific leaf area. This finding also corroborates the importance of soil ionic balance as a plant life driver in microtidal Mediterranean marshes. The effect of past land use on species traits might, however, be partially indirect and mediated by associated environmental changes. © 2014 International Association for Vegetation Science.

Llegeix més

Ecological impacts of small hydropower plants on headwater stream fish: From individual to community effects

Benejam L., Saura-Mas S., Bardina M., Sola C., Munne A., Garcia-Berthou E. (2015) Ecological impacts of small hydropower plants on headwater stream fish: From individual to community effects. Ecology of Freshwater Fish. : 0-0.
Enllaç
Doi: 10.1111/eff.12210

Resum:

Hydroelectricity is increasingly used worldwide as a source of renewable energy, and many mountain ranges have dozens or hundreds of hydropower plants, with many more being under construction or planned. Although the ecological impacts of large dams are relatively well known, the effects of small hydropower plants and their weirs have been much less investigated. We studied the effects of water diversion of small hydropower plants on fish assemblages in the upper Ter river basin (Catalonia, NE Spain), which has headwater reaches with good water quality and no large dams but many of such plants. We studied fish populations and habitat features on control and impacted reaches for water diversion of 16 hydropower plants. In the impacted reaches, there was a significantly lower presence of refuges for fish, poorer habitat quality, more pools and less riffles and macrophytes, and shallower water levels. We also observed higher fish abundance, larger mean fish size and better fish condition in the control than in impacted reaches, although the results were species-specific. Accordingly, species composition was also affected, with lower relative abundance of brown trout (Salmo trutta) and Pyrenean minnow (Phoxinus bigerri) in the impacted reaches and higher presence of stone loach (Barbatula quignardi) and Mediterranean barbel (Barbus meridionalis). Our study highlights the effects of water diversion of small hydropower plants from the individual to the population and community levels but probably underestimates them, urging for further assessment and mitigation of these ecological impacts. © 2014 John Wiley & Sons A/S.

Llegeix més

Could electric fish barriers help to manage native populations of European crayfish threatened by crayfish plague (Aphanomyces astaci)?

Benejam L., Saura-Mas S., Montserrat J., Torres F., Macies M. (2015) Could electric fish barriers help to manage native populations of European crayfish threatened by crayfish plague (Aphanomyces astaci)?. Management of Biological Invasions. 6: 307-310.
Enllaç
Doi: 10.3391/mbi.2015.6.3.10

Resum:

Crayfish plague (Aphanomyces astaci) is the main problem that hinders the conservation of European crayfish species. Every year, dozens of native crayfish populations disappear due to this disease. We used an electric fish barrier to block the dispersal of infected crayfish upstream. One of the main objectives of this communication is to transfer our expertise using this equipment for improved conservation outcomes. As a result, we report a detailed description of the experience, as well as requirements, problems and opportunities of using an electric fish barrier to try to control crayfish plague in-situ. © 2015 The Author(s) and 2015 REABIC.

Llegeix més

Effects of enhanced UV radiation and water availability on performance, biomass production and photoprotective mechanisms of Laurus nobilis seedlings

Bernal M., Verdaguer D., Badosa J., Abadia A., Llusia J., Penuelas J., Nunez-Olivera E., Llorens L. (2015) Effects of enhanced UV radiation and water availability on performance, biomass production and photoprotective mechanisms of Laurus nobilis seedlings. Environmental and Experimental Botany. 109: 264-275.
Enllaç
Doi: 10.1016/j.envexpbot.2014.06.016

Resum:

Climate models predict an increase in ultraviolet (UV) radiation and a reduction in precipitation in the Mediterranean region in the coming decades. High levels of UV radiation and water shortage can both cause photo-oxidative stress in plants. The aim of this study was to investigate the effects of enhanced UV radiation and its interaction with low water availability on seedling performance, biomass production, and photoprotective mechanisms of the sclerophyllous evergreen species Laurus nobilis L. (laurel). To achieve this goal, one-year-old seedlings of L. nobilis were grown outdoors under three UV conditions (ambient UV, enhanced UV-A, and enhanced UV-A. +. UV-B) and under two watering regimes (watered to field capacity and reduced water supply). The results show that plants produced more biomass when exposed to above ambient levels of UV-A or UV-A. +. UV-B radiation, especially under low water availability. This was probably related to a UV-induced increase in leaf relative water content and in leaf water use efficiency under water shortage. Even though our results suggest that UV-A supplementation may play an important role in the stimulation of biomass production, plants grown under enhanced UV-A plots showed higher levels of energy dissipation as heat (measured as NPQ) and a higher de-epoxidation state of the violaxanthin cycle. This suggests a greater excess of light energy under UV-A supplementation, in accordance with the observed reduction in the foliar content of light-absorbing pigments in these plants. Strikingly, the addition of UV-B radiation mitigated these effects. In conclusion, UV enhancement might benefit water status and growth of L. nobilis seedlings, especially under low water availability. The results also indicate the activation of different plant response mechanisms to UV-A and UV-B radiation, which would interact to produce the overall plant response. © 2014 Elsevier B.V.

Llegeix més

Differences in photosynthesis and terpene content in leaves and roots of wild-type and transgenic Arabidopsis thaliana plants

Blanch J.S., Peñuelas J., Llusià J., Sardans J., Owen S.M. (2015) Differences in photosynthesis and terpene content in leaves and roots of wild-type and transgenic Arabidopsis thaliana plants. Russian Journal of Plant Physiology. 62: 823-829.
Enllaç
Doi: 10.1134/S1021443715060035

Resum:

We investigated the hypotheses that two different varieties of Arabidopsis thaliana show differences in physiology and terpene production. The two varieties of A. thaliana used in this study were wild-type (WT) and transgenic line (CoxIV-FaNES I) genetically modified to emit nerolidol with linalool/nerolidol synthase (COX). Photosynthetic rate, electron transport rate, fluorescence, leaf volatile terpene contents and root volatile terpene contents were analyzed. For both types, we found co-eluting α-pinene+β-ocimene, limonene, and humulene in leaves; and in the roots we found co-eluting α-pinene+β-ocimene, sabinene+β-pinene, β-myrcene, limonene, and humulene. At the end of the growing cycle, COX plants tended to have lower pools of terpene compounds in their leaves, with 78.6% lower photosynthesis rates and 30.8% lower electron transport rates, compared with WT plants at that time. The maximal photochemical efficiency Fv/Fm was also significantly lower (25.5%) in COX plants, indicating that these varieties were more stressed than WT plants. However, COX plants had higher (239%) root terpene contents compared to WT plants. COX plants appear to favor root production of volatile terpenes rather than leaf production. Thus we conclude that there were significant differences between COX and WT plants in terms of terpenoid pools, stress status and physiology. © 2015, Pleiades Publishing, Ltd.

Llegeix més

Communicating thematic data quality with web map services

Blower J.D., Masó J., Díaz D., Roberts C.J., Griffiths G.H., Lewis J.P., Yang X., Pons X. (2015) Communicating thematic data quality with web map services. ISPRS International Journal of Geo-Information. 4: 1965-1981.
Enllaç
Doi: 10.3390/ijgi4041965

Resum:

Geospatial information of many kinds, from topographic maps to scientific data, is increasingly being made available through web mapping services. These allow georeferenced map images to be served from data stores and displayed in websites and geographic information systems, where they can be integrated with other geographic information. The Open Geospatial Consortium's Web Map Service (WMS) standard has been widely adopted in diverse communities for sharing data in this way. However, current services typically provide little or no information about the quality or accuracy of the data they serve. In this paper we will describe the design and implementation of a new "quality-enabled" profile of WMS, which we call "WMS-Q". This describes how information about data quality can be transmitted to the user through WMS. Such information can exist at many levels, from entire datasets to individual measurements, and includes the many different ways in which data uncertainty can be expressed. We also describe proposed extensions to the Symbology Encoding specification, which include provision for visualizing uncertainty in raster data in a number of different ways, including contours, shading and bivariate colour maps. We shall also describe new open-source implementations of the new specifications, which include both clients and servers. © 2015 by the authors; licensee MDPI, Basel, Switzerland.

Llegeix més

Unexpected consequences of a drier world: Evidence that delay in late summer rains biases the population sex ratio of an insect

Bonal R., Hernández M., Espelta J.M., Muñoz A., Aparicio J.M. (2015) Unexpected consequences of a drier world: Evidence that delay in late summer rains biases the population sex ratio of an insect. Royal Society Open Science. 2: 0-0.
Enllaç
Doi: 10.1098/rsos.150198

Resum:

The complexity of animal life histories makes it difficult to predict the consequences of climate change on their populations. In this paper, we show, for the first time, that longer summer drought episodes, such as those predicted for the dry Mediterranean region under climate change, may bias insect population sex ratio. Many Mediterranean organisms, like the weevil Curculio elephas, become active again after summer drought. This insect depends on late summer rainfall to soften the soil and allow adult emergence from their underground refuges. We found that, as in many protandric species, more C. elephas females emerged later in the season. Male emergence timing was on average earlier and also more dependent on the beginning of late summer rainfall. When these rains were delayed, the observed weevil sex ratio was biased towards females. So far, the effects of global warming on animal sex ratios has been reported for temperature-dependent sex determination in reptiles. Our results show that rainfall timing can also bias the sex ratio in an insect, and highlight the need for keeping a phenological perspective to predict the consequences of climate change. We must consider not just the magnitude of the predicted changes in temperature and rainfall but also the effects of their timing. © 2015 The Authors.

Llegeix més

Institutional factors and opportunities for adapting European forest management to climate change

Bouriaud L., Marzano M., Lexer M., Nichiforel L., Reyer C., Temperli C., Peltola H., Elkin C., Duduman G., Taylor P., Bathgate S., Borges J.G., Clerkx S., Garcia-Gonzalo J., Gracia C., Hengeveld G., Kellomaki S., Kostov G., Maroschek M., Muys B., Nabuurs G.-J., Nicoll B., Palahi M., Rammer W., Ray D., Schelhaas M.-J., Sing L., Tome M., Zell J., Hanewinkel M. (2015) Institutional factors and opportunities for adapting European forest management to climate change. Regional Environmental Change. : 0-0.
Enllaç
Doi: 10.1007/s10113-015-0852-8

Resum:

Despite the fact that the institutional environment is acknowledged to influence the implementation of regional adaptations of forest management to climate change, there are few empirical studies addressing the institutional factors and opportunities of adaptation. Using Ostrom’s institutional analysis and development framework, we aimed to identify: (1) the critical and distinctive characteristics of the forest resource and institutional context that may determine how climate change-adaptive forest management measures are implemented and (2) the opportunities for implementing the planned adaptation measures. The analysis is performed on ten European case study regions which differed in many resource-dependent factors, policy arena factors and incentives for changes. The main factors influencing the adaptation are the ownership pattern, the level of policy formation and the nature of forest goods and services. Opportunities for adaptation are driven by the openness of the forest management planning processes to the stakeholders participation, the degree to which business as usual management is projected to be non-satisfactory in the future, and by the number and nature of obstacles to adaptation. Promoting local self-governance mechanisms and the participation of the external stakeholders in forest management planning or in the regional forest or climate change policy adaptation may be a way of overcoming path dependency, behavioural obstacles and potential policy failures in implementing adaptation. The study argues that both climate change belief systems and political participation are important to explain adaptation to climate change when multiple decision-making levels are at stake. © 2015 Springer-Verlag Berlin Heidelberg

Llegeix més

Ground-and satellite-based evidence of the biophysical mechanisms behind the greening Sahel

Brandt M., Mbow C., Diouf A.A., Verger A., Samimi C., Fensholt R. (2015) Ground-and satellite-based evidence of the biophysical mechanisms behind the greening Sahel. Global Change Biology. 21: 1610-1620.
Enllaç
Doi: 10.1111/gcb.12807

Resum:

After a dry period with prolonged droughts in the 1970s and 1980s, recent scientific outcome suggests that the decades of abnormally dry conditions in the Sahel have been reversed by positive anomalies in rainfall. Various remote sensing studies observed a positive trend in vegetation greenness over the last decades which is known as the re-greening of the Sahel. However, little investment has been made in including long-term ground-based data collections to evaluate and better understand the biophysical mechanisms behind these findings. Thus, deductions on a possible increment in biomass remain speculative. Our aim is to bridge these gaps and give specifics on the biophysical background factors of the re-greening Sahel. Therefore, a trend analysis was applied on long time series (1987-2013) of satellite-based vegetation and rainfall data, as well as on ground-observations of leaf biomass of woody species, herb biomass, and woody species abundance in different ecosystems located in the Sahel zone of Senegal. We found that the positive trend observed in satellite vegetation time series (+36%) is caused by an increment of in situ measured biomass (+34%), which is highly controlled by precipitation (+40%). Whereas herb biomass shows large inter-annual fluctuations rather than a clear trend, leaf biomass of woody species has doubled within 27 years (+103%). This increase in woody biomass did not reflect on biodiversity with 11 of 16 woody species declining in abundance over the period. We conclude that the observed greening in the Senegalese Sahel is primarily related to an increasing tree cover that caused satellite-driven vegetation indices to increase with rainfall reversal. Copyright © 2015 John Wiley & Sons Ltd214 April 2015 10.1111/gcb.12807 Primary Research Article Primary Research Articles © 2014 John Wiley & Sons Ltd.

Llegeix més

Pàgines