Effectiveness of protected areas in the Colombian Andes: Deforestation, fire and land-use changes

Rodríguez N., Armenteras D., Retana J. (2013) Effectiveness of protected areas in the Colombian Andes: Deforestation, fire and land-use changes. Regional Environmental Change. 13: 423-435.
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Doi: 10.1007/s10113-012-0356-8

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Protected areas (PAs) are one of the most common conservation strategies to halt biodiversity loss. However, little is known about their current effectiveness and how they could behave under projected scenarios of change, especially in the mountain ecosystems of the Andean region. In this study, we assess the role of protected areas against deforestation and fire incidence in the Colombian Andes and how variables associated with biophysical and context drivers such as the size, year of creation and geographic location of the PAs affect their effectiveness. For the long-term, we have addressed the question of how effective these areas will be under three different scenarios of change for the period between 2020 and 2050, including a reference scenario and two scenarios of increasing pastureland and croplands. The results obtained indicated that both deforestation and fire levels were significantly lower inside protected areas than outside their borders. Concerning variables affecting deforestation and fire, only the type of ecosystem affected these processes in this study. The magnitude of forest loss was different between the analysed scenarios and depended on the location of the PAs. The PAs located in the Western Mountain Range presented the largest values of deforestation but the lowest number of fire incidences. This finding could be related to the presence of processes other than fire, such as illegal logging or selective extraction. The largest losses are expected in the PAs associated with the Eastern and Central mountain ranges, whereas the Western Mountain range will have the lowest loss. We conclude that although the Andes Mountains are a highly transformed and dynamic region, the current PAs have been effective barriers for deforestation and fire. However, the creation of new areas and the maintenance of the current PAs should take into account the interaction with the surrounding population, especially in those areas that are more sensitive to change. © 2012 Springer-Verlag Berlin Heidelberg.

Llegeix més

Assessing land-use and -cover changes in relation to geographic factors and urban planning in the metropolitan area of Concepción (Chile). Implications for biodiversity conservation

Rojas C., Pino J., Basnou C., Vivanco M. (2013) Assessing land-use and -cover changes in relation to geographic factors and urban planning in the metropolitan area of Concepción (Chile). Implications for biodiversity conservation. Applied Geography. 39: 93-103.
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Doi: 10.1016/j.apgeog.2012.12.007

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The conservation of biodiversity in Latin American metropolitan areas is threatened by the intense land-use and -cover change. Assessing the overall biodiversity changes in entire regions faces with the traditional lack of consistent biodiversity data. This work aims at contributing to this assessment through a set of major pressures to biodiversity defined from land-use and -cover changes, and evaluating their extent, distribution and correlations with geographical variables. The study was performed in the framework of the Metropolitan Urban Plan of Concepción (MUPC, Chile). Land-use and -cover maps were obtained through image classification for the years 2000 and 2010, before and after the MUPC approval, and combined in a land-use and -cover change (LUCC) map. A set of pressures to biodiversity (natural and artificial forestation, deforestation, agricultural abandonment and expansion, and urbanization) was obtained from reclassifying the LUCC map. The correlations of these pressures with a set of geographical variables were assessed using canonical ordination methods. Finally, a preliminary forecast analysis of the effects of the MUPC was performed by combining the land-use and -cover map of 2010 with the urban-extension areas of the plan.Results showed that, in only 10 years, 57% of the Concepción Metropolitan Area (CMA) was affected by land-use and -cover changes, and 48% was affected by the pressures to biodiversity. Artificial forestation and deforestation were the dominant pressures, followed by agricultural abandonment and urbanization. The geographical distribution of pressures during the 2000-2010 period also contributed to affect the conservation of biodiversity and the sustainable management of the CMA. Indeed, natural forestation occurred close to urbanization, thus threatening the ecological integrity of native forests, while artificial forestation, deforestation and agricultural abandonment took place in steeply areas thus increasing landslide risk. Despite urbanization was not the most relevant pressure in the short studied period, urban development planned in the MUPC would determine an overall increase of 60% in the built-up area of the CMA, mostly affecting brushwood and forest plantations but also native forest and wetlands. Implications of these results for the strategic environmental assessment (SEA) and the sustainable management of Latin American metropolis are finally discussed. © 2013 Elsevier Ltd.

Llegeix més

Strategic Environmental Assessment in Latin America: A methodological proposal for urban planning in the Metropolitan Area of Concepción (Chile)

Rojas C., Pino J., Jaque E. (2013) Strategic Environmental Assessment in Latin America: A methodological proposal for urban planning in the Metropolitan Area of Concepción (Chile). Land Use Policy. 30: 519-527.
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Doi: 10.1016/j.landusepol.2012.04.018

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This work describes a methodology for Strategic Environmental Assessment of urban areas in Latin America based on the recently approved European Planning Directive, and applies it to the Metropolitan Area of Concepción (Chile). The method is based on the Land Suitability Index (LSI), a cartographic GIS-based index originally developed for the region of Barcelona (Spain) and aimed at determining the suitability of each point in a region for urban development, considering three sub-indexes: (i) Naturalness, (ii) Ecological Connectivity and (iii) Natural Risk. Using the LSI we evaluated the already approved urban plans of the municipalities in the region, considering two scenarios: the initial land use or baseline scenario (S0) and the designated land use or planned scenario (S1). The results show that overall the planned scenario will result in a loss of around 16% of naturalness, with particularly negative effects on brushwood and wetland areas. Connectivity will decrease by around 17%, and urban areas exposed to many types of natural risks will increase considerably, from approximately 49% to 92% of the total urban surface. Finally the LSI shows that around 252 ha are suitable for new urbanization in the extension area. This corresponds to around 0.7% of the total extension area (37.381 ha), which represents 12% of the region (271.398 ha). We propose this methodology can be a valuable contribution to the design of Strategic Environmental Assessment applications and indicators for land planning in Latin America. © 2012 Elsevier Ltd.

Llegeix més

Dynamics of non-structural carbohydrates in three mediterranean woody species following long-term experimental drought

Rosas T., Galiano L., Ogaya R., Penuelas J., Martinez-Vilalta J. (2013) Dynamics of non-structural carbohydrates in three mediterranean woody species following long-term experimental drought. Frontiers in Plant Science. 4: 0-0.
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Doi: 10.3389/fpls.2013.00400

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Stored non-structural carbohydrates (NSC) have been proposed as a key determinant of drought resistance in plants. However, the evidence for this role is controversial, as it comes mostly from observational, short-term studies. Here, we take advantage of a long-term experimental throughfall reduction to elucidate the response of NSC to increased drought 14 years after the beginning of the treatment in three Mediterranean resprouter trees (Quercus ilex L., Arbutus unedo L. and Phillyrea latifclia L.). In addition, we selected 20. Q. ilex individuals outside the experimental plots to directly assess the relationship between defoliation and NSC at the individual level. We measured the seasonal course of NSC concentrations in leaves, branches and lignotuber in late winter, late spring, summer, and autumn 2012. Total concentrations of NSC were highest in the lignotuber for all species. In the long-term drought experiment we found significant depletion in concentrations of total NSC in treatment plots only in the lignotuber of A. unedo. At the same time, A. unedo was the only species showing a significant reduction in BAI under the drought treatment during the 14 years of the experiment. By contrast, Q. ilex just reduced stem growth only during the first 4 years of treatment and P latifclia remained unaffected over the whole study period. However, we found a clear association between the concentrations of NSC and defoliation in Q. ilex individuals sampled outside the experimental plots, with lower total concentrations of NSC and lower proportion of starch in defoliated individuals. Taken together, our results suggest that stabilizing processes, probably at the stand level, may have been operating in the long-term to mitigate any impact of drought on NSC levels, and highlight the necessity to incorporate long-term experimental studies of plant responses to drought. © 2013 Rosas, Galiano, Ogaya, Peñuelas and Martínez-Vilalta.

Llegeix més

Comparing the effect of salvage logging on birds in the Mediterranean Basin and the Rocky Mountains: Common patterns, different conservation implications

Rost J., Hutto R.L., Brotons L., Pons P. (2013) Comparing the effect of salvage logging on birds in the Mediterranean Basin and the Rocky Mountains: Common patterns, different conservation implications. Biological Conservation. 158: 7-13.
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Doi: 10.1016/j.biocon.2012.08.022

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Postfire salvage logging is currently a controversial issue because of the impact that the removal of snags has on ecosystem structure and function. Although it is a common practice worldwide, the absence of comparisons across regions hinders the development of broad generalizations. Here we compare bird response to postfire salvage logging in two regions with significant differences in landscape and bird communities, the Mediterranean Basin and the Rocky Mountains. The Mediterranean Basin features a landscape dominated by a mosaic of small-sized forests, farmland and shrublands, while the Rocky Mountains have large extensions of continuous forests. Bird conservation priorities are also different. In the Mediterranean Basin, priorities are oriented toward farmland birds, while they are oriented toward fire-specialists in the Rocky Mountains. We used databases describing bird species occurrence in burned forests from both regions and defined three groups of species based on their level of association with snags. We then compared the richness of each group among logged and unlogged sites, and also between regions. We found a higher proportion of species that showed some degree of association with snags in burned forests of the Rocky Mountains than in the Mediterranean Basin. Highly snag-associated birds from both regions showed a common negative response to salvage logging. Not snag-associated species increased in salvaged areas, but only in the Mediterranean Basin. The general negative effect of salvage logging on forest-dwelling species that are associated with trees or snags is a noteworthy pattern given the big differences between regions. Nevertheless, in the Mediterranean, some threatened farmland species benefit from logging, so the overall effect of the removal of snags appears to be relatively more detrimental to birds in the Rocky Mountains. © 2012 Elsevier Ltd.

Llegeix més

Contrasting vulnerability and resilience to drought-induced decline of densely planted vs. natural rear-edge Pinus nigra forests

Sanchez-Salguero R., Camarero J.J., Dobbertin M., Fernandez-Cancio T., Vila-Cabrera A., Manzanedo R.D., Zavala M.A., Navarro-Cerrillo R.M. (2013) Contrasting vulnerability and resilience to drought-induced decline of densely planted vs. natural rear-edge Pinus nigra forests. Forest Ecology and Management. 310: 956-967.
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Doi: 10.1016/j.foreco.2013.09.050

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The southernmost European natural and planted pine forests are among the most vulnerable areas to warming-induced drought decline. Both drought stress and management factors (e.g., stand origin or reduced thinning) may induce decline by reducing the water available to trees but their relative importances have not been properly assessed. The role of stand origin - densely planted vs. naturally regenerated stands - as a decline driver can be assessed by comparing the growth and vigor responses to drought of similar natural vs. planted stands. Here, we compare these responses in natural and planted Black pine (Pinus nigra) stands located in southern Spain. We analyze how environmental factors - climatic (temperature and precipitation anomalies) and site conditions - and biotic factors - stand structure (age, tree size, density) and defoliation by the pine processionary moth - drive radial growth and crown condition at stand and tree levels. We also assess the climatic trends in the study area over the last 60. years. We use dendrochronology, linear mixed-effects models of basal area increment and structural equation models to determine how natural and planted stands respond to drought and current competition intensity. We observed that a temperature rise and a decrease in precipitation during the growing period led to increasing drought stress during the late 20th century. Trees from planted stands experienced stronger growth reductions and displayed more severe crown defoliation after severe droughts than those from natural stands. High stand density negatively drove growth and enhanced crown dieback, particularly in planted stands. Also pine processionary moth defoliation was more severe in the growth of natural than in planted stands but affected tree crown condition similarly in both stand types. In response to drought, sharp growth reduction and widespread defoliation of planted Mediterranean pine stands indicate that they are more vulnerable and less resilient to drought stress than natural stands. To mitigate forest decline of planted stands in xeric areas such as the Mediterranean Basin, less dense and more diverse stands should be created through selective thinning or by selecting species or provenances that are more drought tolerant. © 2013 Elsevier B.V.

Llegeix més

Tree growth changes with climate and forest type are associated with relative allocation of nutrients, especially phosphorus, to leaves and wood

Sardans J., Penuelas J. (2013) Tree growth changes with climate and forest type are associated with relative allocation of nutrients, especially phosphorus, to leaves and wood. Global Ecology and Biogeography. 22: 494-507.
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Doi: 10.1111/geb.12015

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Aim: To test our hypothesis that trees change the allocation and the proportion of different nutrients between leaves and wood to maximize growth along climatic gradients. Location: Catalonia, Iberian Peninsula. Methods: We tested the relationships of total forest nutrient content, stoichiometry and allocation between leaves and wood in trees with growth along environmental gradients using data from the Catalan Forest Inventory and a suite of multivariate mixed models, ANOVAs and principal components analyses. Results: The aboveground growth of trees and the nutrient content of leaves and wood were positively correlated with mean annual precipitation (MAP). The changes in C:nutrient ratios were proportionally higher in leaves than in wood, mainly in deciduous forests. Higher MAP was also related to a lower N:P content ratio in leaves and wood but was not related to a greater allocation of P than N in leaves relative to wood (N:PL/W). Conifers, which presented the highest relative aboveground growth, had the lowest N:PL/W (0.99 ± 0.02), whereas the slow-growing evergreens had the highest N:PL/W (2.26 ± 0.23). Main conclusions: In all forest types, growth was related to a higher allocation of nutrients to leaves than to wood, especially of P, coinciding with better climatic conditions for growth (higher MAP in this Mediterranean context). The highest rates of growth were linked to the lowest N:P ratios. The allocation of P relative to N in leaves is higher in conifers than in evergreen and deciduous trees. © 2012 Blackwell Publishing Ltd.

Llegeix més

Plant-soil interactions in Mediterranean forest and shrublands: Impacts of climatic change

Sardans J., Penuelas J. (2013) Plant-soil interactions in Mediterranean forest and shrublands: Impacts of climatic change. Plant and Soil. 365: 1-33.
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Doi: 10.1007/s11104-013-1591-6

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Background: In the Mediterranean climate, plants have evolved under conditions of low soil-water and nutrient availabilities and have acquired a series of adaptive traits that, in turn exert strong feedback on soil fertility, structure, and protection. As a result, plant-soil systems constitute complex interactive webs where these adaptive traits allow plants to maximize the use of scarce resources. Scope: It is necessary to review the current bibliography to highlight the most know characteristic mechanisms underlying Mediterranean plant-soil feed-backs and identify the processes that merit further research in order to reach an understanding of the plant-soil feed-backs and its capacity to cope with future global change scenarios. In this review, we characterize the functional and structural plant-soil relationships and feedbacks in Mediterranean regions. We thereafter discuss the effects of global change drivers on these complex interactions between plants and soil. Conclusions: The large plant diversity that characterizes Mediterranean ecosystems is associated to the success of coexisting species in avoiding competition for soil resources by differential exploitation in space (soil layers) and time (year and daily). Among plant and soil traits, high foliar nutrient re-translocation and large contents of recalcitrant compounds reduce nutrient cycling. Meanwhile increased allocation of resources to roots and soil enzymes help to protect against soil erosion and to improve soil fertility and capacity to retain water. The long-term evolutionary adaptation to drought of Mediterranean plants allows them to cope with moderate increases of drought without significant losses of production and survival in some species. However, other species have proved to be more sensitive decreasing their growth and increasing their mortality under moderate rising of drought. All these increases contribute to species composition shifts. Moreover, in more xeric sites, the desertification resulting from synergic interactions among some related process such as drought increases, torrential rainfall increases and human driven disturbances is an increasing concern. A research priority now is to discern the effects of long-term increases in atmospheric CO2 concentrations, warming, and drought on soil fertility and water availability and on the structure of soil communities (e. g., shifts from bacteria to fungi) and on patching vegetation and root-water uplift (from soil to plant and from soil deep layers to soil superficial layers) roles in desertification. © 2013 Springer Science+Business Media Dordrecht.

Llegeix més

Field-simulated droughts affect elemental leaf stoichiometry in Mediterranean forests and shrublands

Sardans J., Rivas-Ubach A., Estiarte M., Ogaya R., Penuelas J. (2013) Field-simulated droughts affect elemental leaf stoichiometry in Mediterranean forests and shrublands. Acta Oecologica. 50: 20-31.
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Doi: 10.1016/j.actao.2013.04.002

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This study evaluated the change induced by the year season and by experimentally induced drought on foliar element stoichiometry of the predominant woody species (. Quercus ilex and Erica multiflora) in two Mediterranean ecosystems, a forest and a shrubland. This study is based in two long-term (11yr) field experiments that simulated drought throughout the annual cycle.The effects of experimental droughts were significant but weaker than the changes produced by ontogeny and seasonality. Leaf N and P concentrations were higher in spring (the main growing season) in E. multiflora and, in Q.ilex in autumn (a period of additional growth). Leaf N:P ratios were lower in spring. In Q.ilex, the highest leaf K concentrations and leaf K:P ratios, and the lowest leaf C:K and N:K ratios, occurred in summer, the season when water stress was greatest. In E.multiflora, leaf K concentrations and K:P ratios were highest, and leaf C:K and N:K ratios were lowest in the plants from the drought-treated plots.The plant capacity to change K concentrations in response to seasonality and to drought is at least as great as the capacity to change N and P concentrations. The results underscore the importance of K and its stoichiometry relative to C, N and P in dry environments. These results indicate first, that N:P ratio shifts are not uniquely related to growth rate in Mediterranean plants but also to drought, and second, that there is a need to take into account K in ecological stoichiometry studies of terrestrial plants. © 2013 Elsevier Masson SAS.

Llegeix més

Monitoring, modelling and forecasting of the pollen season

Scheifinger H., Belmonte J., Buters J., Celenk S., Damialis A., Dechamp C., García-Mozo H., Gehrig R., Grewling L., Halley J.M., Hogda K.-A., Jäger S., Karatzas K., Karlsen S.-R., Koch E., Pauling A., Peel R., Sikoparija B., Smith M., Galán-Soldevilla C., Thibaudon M., Vokou D., De Weger L.A. (2013) Monitoring, modelling and forecasting of the pollen season. Allergenic Pollen: A Review of the Production, Release, Distribution and Health Impacts. 9789400748811: 71-126.
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Doi: 10.1007/978-94-007-4881-1_4

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The section about monitoring covers the development of phenological networks, remote sensing of the season cycle of the vegetation, the emergence of the science of aerobiology and, more specifically, aeropalynology, pollen sampling instruments, pollen counting techniques, applications of aeropalynology in agriculture and the European Pollen Information System. Three data sources are directly related with aeropalynology: phenological observations, pollen counts and remote sensing of the vegetation activity. The main future challenge is the assimilation of these data streams into numerical pollen forecast systems. Over the last decades consistent monitoring efforts of various national networks have created a wealth of pollen concentration time series. These constitute a nearly untouched treasure, which is still to be exploited to investigate questions concerning pollen emission, transport and deposition. New monitoring methods allow measuring the allergen content in pollen. Results from research on the allergen content in pollen are expected to increase the quality of the operational pollen forecasts. In the modelling section the concepts of a variety of process-based phenological models are sketched. Process-based models appear to exhaust the noisy information contained in commonly available observational phenological and pollen data sets. Any additional parameterisations do not to improve model quality substantially. Observation-based models, like regression models, time series models and computational intelligence methods are also briefly described. Numerical pollen forecast systems are especially challenging. The question, which of the models, regression or process-based models is superior, cannot yet be answered. © 2013 Springer Science+Business Media Dordrecht. All rights reserved.

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