Typical Mediterranean Forest Research Articles

Habitat fragmentation in a Mediterranean-type forest alters resident and propagule mycorrhizal fungal communities

AimsAnthropogenic activities disturb forests and their associated mycorrhizal fungi. The combination of climate change and habitat fragmentation are linked to increased incidence of a canker disease in a Mediterranean-type forest tree in Western Australia. As changes in communities of mycorrhizal fungi could predispose these Mediterranean-type forest trees to decline, we investigated how two aspects of mycorrhizal fungal community structure, soil propagules and resident communities on mature trees, respond to habitat fragmentation. MethodsRoots were collected from a forest tree (Corymbia calophylla) across a disturbance gradient. Soil collected from the same disturbance gradient was used in a glasshouse bioassay with C. calophylla as the bioassay host (i.e., soil propagule community). After four months, we harvested the seedlings and collected roots. DNA was extracted from the field roots (resident community) and glasshouse roots (propagule community), amplified with fungal specific primers, labelled with specific barcodes and subjected to 454 pyrosequencing. ResultsMycorrhizal fungal community composition overlapped substantially between the soil propagule and resident communities. However, the resident community had greater mycorrhizal fungal richness than the soil propagule community. Habitat fragmentation had a similar effect on each community structure: communities along highly fragmented areas had different community compositions than communities in a healthy forest. ConclusionWith the increased mortality of C. calophylla forest trees in recent years along edge habitats, understanding the effects habitat fragmentation has on communities of mycorrhizal fungi will further elucidate host-mutualist interactions in these forest ecosystems. The changes in community composition of mycorrhizal fungal species in both propagule and resident pools can have cascading effects on future tree establishment and health by predisposing forest trees to other abiotic or biotic factors.

Biomass and dominance of conservative species drive above-ground biomass productivity in a mediterranean-type forest of Chile

BackgroundForest productivity has a pivotal role in human well-being. Vegetation quantity, niche complementarity, mass-ratio, and soil resources are alternative/complementary ecological mechanisms driving productivity. One challenge in current forest management depends on identifying and manipulating these mechanisms to enhance productivity. This study assessed the extent to which these mechanisms control above-ground biomass productivity (AGBP) of a Chilean mediterranean-type matorral. AGBP measured as tree above-ground biomass changes over a 7-years period, was estimated for twelve 25 m × 25 m plots across a wide range of matorral compositions and structures. Variables related to canopy structure, species and functional diversity, species and functional dominance, soil texture, soil water and soil nitrogen content were measured as surrogates of the four mechanisms proposed. Linear regression models were used to test the hypotheses. A multimodel inference based on the Akaike’s information criterion was used to select the best models explaining AGBP and for identifying the relative importance of each mechanism.ResultsVegetation quantity (tree density) and mass-ratio (relative biomass of Cryptocarya alba, a conservative species) were the strongest drivers increasing AGBP, while niche complementarity (richness species) and soil resources (sand, %) had a smaller effect either decreasing or increasing AGBP, respectively. This study provides the first assessment of alternative mechanisms driving AGBP in mediterranean forests of Chile. There is strong evidence suggesting that the vegetation quantity and mass-ratio mechanisms are key drivers of AGBP, such as in other tropical and temperate forests. However, in contrast with other studies from mediterranean-type forests, our results show a negative effect of species diversity and a small effect of soil resources on AGBP.ConclusionAGBP in the Chilean matorral depends mainly on the vegetation quantity and mass-ratio mechanisms. The findings of this study have implications for matorral restoration and management for the production of timber and non-timber products and carbon sequestration.

Recent radial growth decline in response to increased drought conditions in the northernmost Nothofagus populations from South America

Abstract An emerging phenomenon of forest decline in Mediterranean-type ecosystems has been detected in response to climate change during the last century. It is expected that the Mediterranean regions will likely experience drought events during this century with consequences for biodiversity maintenance. Although the Chilean Mediterranean-type forests are among the most threatened forest ecosystems in South America, their responses to recent increased drought events due to global warming are poorly documented. In the same region, the endangered and endemic forests of Nothofagus macrocarpa (Nothofagaceae) are found on mountain peaks. It is unclear how N. macrocarpa forests are responding to increased drought conditions occurring in the area over the last few decades. Here, we analyzed how recent climatic variability has affected the growth of N. macrocarpa. We selected five sites along the whole geographic distribution of N. macrocarpa forests in central Chile (32.5–34.5°S) to develop tree-ring chronologies. Climate-growth relationships were analyzed through correlations with local (precipitation, temperature and drought index) and large-scale climate data (ENSO index and Antarctic Oscillation). N. macrocarpa growth was positively influenced by May to November precipitation (austral winter-spring seasons) and negatively influenced by temperature from October to December (austral spring/early-summer seasons). Using a piecewise regression analysis, we identified a significant decrease in growth from 1980 onwards that resembled a precipitation decline and temperature increase in central Chile during the same time period. Tree-ring chronologies were positively correlated to the ENSO index and negatively correlated to the Antarctic Oscillation index during the current growing season, and more strongly from 1980 onwards. Based on our results, we conclude that increased drought conditions have produced a decline in radial growth of N. macrocarpa forests in the last decades. We propose that increased drought conditions predicted for this century in this region will exacerbate this declining N. macrocarpa growth trend with unknown consequences for the survival of these endemic and endangered forest ecosystems.

Consideration of Landsat-8 Spectral Band Combination in Typical Mediterranean Forest Classification in Halkidiki, Greece

AbstractUtilization of satellite data by means of remote sensing practices creates a wider window of opportunities to conduct robust outcomes Landsat OLI-8 data acquired over the peninsula of Halkidiki in Greece for the summer period of 2013, were analyzed to determine their utility to classify natural resources categories based on the determination of spectral bands combination. Consequently, spectral bands combination can be used to classify various categories based on their higher overall accuracy assessment. Spectral information contained in each of the utilized channels of Landsat OLI-8, statistics defining 12 cover type classes of interest were calculated and used as a basis for classification of the designated study area. Spectral bands combinations (4-5-6/ 3-4-5/ 3-4-5-6/ 4-5-6-7) fulfill the required accuracy for forest purpose as they conducted overall accuracies ranging between 7.85% and 96.29%. The spectral band combination 3-4-5-6-7 conducted the highest overall accuracy (98.15%). The poorest results were obtained by the analysis of spectral bands combination 4-6 (68.52%). Single spectral band 6 conducted the best overall results; however, spectral bands 5 and 6 seemed to be the most useful spectral bands combination for each category.

Relationships between climate, topography, water use and productivity in two key Mediterranean forest types with different water-use strategies

Climate and topography have both strong effects on forest water and carbon cycles. However, little is known about their combined effects on the long-term water use and productivity of forests that have different water-use strategies. Here, we used structural equation modelling (SEM) to test direct and indirect influences of climate and topography on the long-term (mean over 2000–2014) evapotranspiration (ET) and gross ecosystem productivity (GEP), as assessed from satellite-based models, across two major co-occurring Mediterranean forest types with different water-use strategies (oak woodlands and pine forests). The estimated GEP and ET were higher by c. 6% and 15%, respectively, in the oak woodlands (Quercus calliprinos) than in pine forests (Pinus halepensis). As a result, the water use efficiency was higher in the pine forests (by 9%), consistent with P. halepensis conservative behaviour. Using the SEM, we found that the mean annual surface skin temperatures had the largest influence on the productivity and ET, with a similar net adverse effect across both forest types. In contrast, the mean annual precipitation was not related to GEP across both forest types but positively affected the ET in the oak woodlands. Slope and aspect had both significant but secondary influence on the forests fluxes, with higher GEP and ET found on the steeper slopes across the oak woodlands and higher ET found on the steeper slopes across the pine forests, associated with north-facing aspects. Applying the SEMs for the pine and oak forests, we predicted reductions of 16% and 31% in the productivity of both forests for projected increases in temperatures of 1°C and 2°C, respectively. Our results suggest that projected warming may have a strong impact on the productivity of Mediterranean forests, severely decreasing the CO2 uptake of the trees, independent of their water-use strategy.

Diversity distribution of saproxylic beetles in Chilean Mediterranean forests: influence of spatiotemporal heterogeneity and perturbation

Mediterranean ecosystems have been recognized as a priority for biodiversity conservation due to their high levels of species richness and endemism. In South America, these environments are restricted to central Chile and represent a biodiversity hotspot. The study of saproxylic beetles in this area is an unexplored topic, despite the ecological role they play in these ecosystems and their potential usefulness for monitoring the degree of forest conservation. We investigated the diversity distribution of trophic guilds of saproxylic beetles in Chilean Mediterranean forests, to identify the main environmental variables that influence their distribution. We also analyzed seasonal dynamics as a key factor influencing insect communities and the effect of human disturbance on their diversity and composition. We identified characteristic species of perturbation degree as bioindicators for habitat monitoring. A total of 40 window traps were used to survey three Mediterranean forest types in the Rio Clarillo National Reserve and the adjacent non-protected areas. We found that the diversity, abundance and composition of saproxylic beetles varied significantly spatiotemporally among the studied forest types and among perturbation degrees, showing different patterns depending on the trophic guild. Results indicated that conservation decisions should include the preservation of a larger range of different vegetation types and the nearby zones that have suffered low levels of disturbance or fragmentation and where actions promoting the presence of old native trees would have a significant conservation value.

Mediterranean forests, land use and climate change: a social-ecological perspective

Mediterranean forests are found in the Mediterranean basin, California, the South African Cape Province, South and southwestern Australia and parts of Central Chile. They represent 1.8 % of the world forest areas of which the vast majority is found in the Mediterranean basin, where historical and paleogeographic episodes, long-term human influence and geographical and climatic contrasts have created ecosystemic diversity and heterogeneity. Even if evergreen is dominant, deciduous trees are also represented, with different forest types including dense stands with a closed canopy (forests sensu stricto) and pre-forestal or pre-steppic structures with lower trees density and height. The Mediterranean basin is also a hot spot of forest species and genetic diversity, with 290 woody species versus only 135 for non-Mediterranean Europe. However, the characteristics of the Mediterranean area (long-standing anthropogenic pressure, significant current human activity and broad biodiversity) make it one of the world’s regions most threatened by current changes. Four examples of Mediterranean forest types, present in south and north of the Mediterranean basin and more or less threatened, are developed in order to show that linking “hard sciences” and humanities and social sciences is necessary to understand these complex ecosystems. We show also that these forests, in spite of specific climatic constraints, can also be healthy and productive and play a major ecological and social role. Furthermore, even if the current human activity and global change constitute a risk for these exceptional ecosystems, Mediterranean forests represent a great asset and opportunities for the future of the Mediterranean basin.

Post-fire recovery of soil organic matter in a Cambisol from typical Mediterranean forest in Southwestern Spain

Wildfire is a recurrent phenomenon in Mediterranean ecosystems and contributes to soil degradation and desertification, which are partially caused by alterations to soil organic matter (SOM). The SOM composition from a Cambisol under a Mediterranean forest affected by a wildfire is studied in detail in order to assess soil health status and better understand of soil recovery after the fire event. The soil was sampled one month and twenty-five months after the wildfire. A nearby unburnt site was taken as control soil. Soil rehabilitation actions involving heavy machinery to remove burnt vegetation were conducted sixteen months after the wildfire. Immediately after fire the SOM increased in topsoil due to inputs from charred vegetation, whereas a decrease was observed in the underlying soil layer. Twenty-five months after fire soil-pH increased in fire-affected topsoil due to the presence of ashes, a decrease in SOM content was recorded for the burnt topsoil and similar trend was observed for the water holding capacity. The pyro-chromatograms of burned soils revealed the formation of additional aromatic compounds. The thermal cracking of long-chain n-alkanes was also detected. Solid-state 13C NMR spectroscopy supported the increase of aromatic compounds in the fire-affected topsoil due to the accumulation of charcoal, whereas the deeper soil sections were not affected by the fire. Two years later, soil parameters for the unburnt and burnt sites showed comparable values. The reduction of the relative intensity in the aromatic C region of the NMR spectra indicated a decrease in the charcoal content of the topsoil. Due to the negligible slope in the sampling site, the loss of charcoal was explained by the post-fire restoration activity, degradation, leaching of pyrogenic SOM into deeper soil horizons or wind erosion. Our results support that in the Mediterranean region, fire-induced alteration of the SOM is not lasting in the long-term.

An index for the assessment of degraded Mediterranean forest ecosystems

Aim of study: Diagnosing the degradation degree of forest ecosystems is the basis for restoration strategies. However, there is no literature documenting how to quantify the forest degradation degree by using synthetic indicators, also because there is not a widely accepted definition for "forest degradation" and "degraded forest". Although there are many definitions of forest degradation that converge on the loss of ecosystem services, still today there are no largely accepted methods that give operational guidance to help in defining it. In the present research, with the aim to assess the degree of forest degradation, an integrated index - FDI, Forest Degradation Index - was developed.Area of study: In this first application, the FDI was applied and validated at stand level in two different Mediterranean forest types in two different case studies: Madonie and Nedrodi regional Parks (Sicily, Italy). The first dominated by sessile oak [Quercus petraea (Matt.) Liebl. subsp. austrotyrrhenica Brullo, Guarino & Siracusa], the second dominated by cork oak (Quercus suber L.).Material and methods: FDI is a synthetic index structured starting from representative and relatively easily detectable parameters. Here, we propose a set of six indicators that should be assessed to determine the forest degradation: Structural Index (SI), Canopy Cover (CC), Natural Regeneration Density (NRD), Focal Species of Degradation (FSD), Coarse Woody Debris (CWD), and Soil Depth (SD). FDI, here proposed and discussed, has been based on a MCDA (Multi-Criteria Decision Analysis) approach using the Analytic Hierarchy Process (AHP) technique, and implemented in order to contribute in finding simple indicators useful for forest restoration purposes that have an eco-functional basis.Main results: An integrated index of forest degradation has been defined. FDI values are comprised in the closed interval [0, 10], ranging from class I (Higher ecological functionality) to class IV (Lower ecological functionality). A forest fallen in the FDI-IV class can be defined degraded. In this first application, degradation occurs in SA-4 and in SB-4 where the lowest values (qualitative and quantitative) of the indicators were recorded and the FDI reach the minimum value.Research highlights: FDI has proved to be a useful tool at stand level in identifying a threshold value below which a forest can be termed as ‘degraded’. In turn, FDI assumes the meaning of descriptor of the ecological functionality. Future development of the FDI will provide an extension of the application at landscape scale exploiting the potential advantages in coupling MCDA and GIS (Geographical Information Systems) techniques.Keywords: Forest Degradation Index (FDI); Sustainable Forest Management (SFM); Mediterranean Forest Landscape; Multi-Criteria Decision Analysis (MCDA) approach; Analytic Hierarchy Process (AHP).

Climate response of the soil nitrogen cycle in three forest types of a headwater Mediterranean catchment

Future changes in climate may affect soil nitrogen (N) transformations, and consequently, plant nutrition and N losses from terrestrial to stream ecosystems. We investigated the response of soil N cycling to changes in soil moisture, soil temperature, and precipitation across three Mediterranean forest types (evergreen oak, beech, and riparian) by fusing a simple process-based model (which included climate modifiers for key soil N processes) with measurements of soil organic N content, mineralization, nitrification, and concentration of ammonium and nitrate. The model describes sources (atmospheric deposition and net N mineralization) and sinks (plant uptake and hydrological losses) of inorganic N from and to the 0–10 cm soil pool as well as net nitrification. For the three forest types, the model successfully recreated the magnitude and temporal pattern of soil N processes and N concentrations (Nash-Sutcliffe coefficient = 0.49–0.96). Changes in soil water availability drove net N mineralization and net nitrification at the oak and beech forests, while temperature and precipitation were the strongest climatic factors for riparian soil N processes. In most cases, net N mineralization and net nitrification showed a different sensitivity to climatic drivers (temperature, soil moisture, and precipitation). Our model suggests that future climate change may have a minimal effect on the soil N cycle of these forests (<10% change in mean annual rates) because positive warming and negative drying effects on the soil N cycle may counterbalance each other.

Climate changes in the central Mediterranean and Italian vegetation dynamics since the Pliocene

Pollen records and pollen-based climate reconstructions from the Italian peninsula (central Mediterranean) show clear signals of vegetation change linked to variations in water availability in the Mediterranean basin over the past 5millionyears. Profound vegetation changes occurred in four major steps from the Pliocene to the present. The subtropical taxa that dominate Pliocene assemblages declined and then disappeared between 3–2.8 and 1.66Ma (at around 2.8Ma in the North and later in the South), progressively being replaced by temperate Quercus forests at mid altitude. In the south Italy, Quercus expanded more at around 1.4–1.3Ma and Fagus proportions increased after 0.5Ma. Conifer forest (first mainly composed of Tsuga then by Abies and Picea) began to expand at 2.8Ma, probably rather at high altitude, beginning at 2.8Ma. Mediterranean-type forest, rare during the Early Pleistocene, developed and increased in diversity during the Middle Pleistocene. Open landscapes, with higher abundances of steppic taxa, became more frequent and extensive at the onset of Glacial/Interglacial (G/I) cyclicity around 2.6Ma and gradually expanded with more and more marked glacials. Climate reconstructions done on selected pollen records from southern Italy suggest a decline in winter temperature and annual precipitation from the early Pleistocene to the Holocene. Specifically, both precipitation and winter temperature reconstructions show changes in interglacial maxima and glacial minima at around 3–2.8Ma, 2Ma, 1.3–1.4Ma and 0.5Ma.This critical review provides evidence that the North–South precipitation gradient, with drier conditions in the South, has been a consistent feature of the Italian peninsula since the beginning of the Pleistocene.

Community resilience and land degradation in forest and shrubland socio-ecological systems: Evidence from Gorgoglione, Basilicata, Italy

Assessing the resilience of communities is assuming greater importance at a time of global economic upheaval, climatic and socio-demographic changes. The past 10–15 years have seen a significant increase in the number of studies addressing resilience issues at community level from a variety of perspectives, and although the resilience of communities in dealing with disturbance feature strongly in these studies, less work appears to have been undertaken at the interface between community resilience and land degradation. In addition, little attention has been paid to land degradation, desertification risk and community resilience at the forest–community interface, despite the fact that forest ecosystems represent one of the most important terrestrial biomes in terms of the ecosystem services and socio-economic benefits that they provide. Building on existing community resilience literature which highlights the importance of various socio-economic and political drivers for understanding community resilience, this paper analyses how economic, political, institutional, social, cultural and natural factors at community level affect the ability of communities to adapt and adjust decision-making pathways towards resilience. The paper will focus on the municipality of Gorgoglione (Basilicata, Italy), a typical Mediterranean forest and shrubland socio-ecological system characterised by a mixture of agricultural and forest landscapes prone to land degradation issues linked to both anthropogenic (deforestation, overgrazing, forest fires) and natural (soil erosion, droughts, climate aridity) causes. A mixed-method approach is used, drawing on quantitative and qualitative data across spatial levels and temporal scales to examine the complex interrelationships between community resilience, forest ecosystems and land degradation.

Floristic Features, Distribution, and Ethnobotany of Plants Gathered and Used by Local People from the Mediterranean Forest in Northern Jordan

وتنفيذ مشاريع الحفاظ و إعادة تأهيل الغابات في الغابات البحر المتوسطية مع إشراك المجتمعات المحلية في هذه العمليات .&nbsp;الأهداف (1) دراسة نمط توزيع (2) تحليل المميزات النباتية (3) التحقيق في الاستخدامات الرئيسية للنباتات التي تم جمعها من ثلاث النظم الإيكولوجية للغابات البحر الأبيض المتوسط في شمال الأردن.&nbsp;طرق البحث : تم اختيار 14 قرية وفقا لموقعها على حافة و داخل أنواع الغابات المتوسطية الثلاث في الجزء الشمالي من الأردن ، و 300 من السكان المحليين وأجريت مقابلات وجها لوجه باستخدام استبيان شبه منظم . وشملت البيانات التي تم الحصول عليها وما هي النباتات التي تم جمعها وماذا عن الاستفادة منها. وأجري تحليل Detrended Correspondence Analysis (DCA)من أجل التحقيق في توزيع الأنواع النباتية التي تم جمعها من ثلاثة أنواع الغابات وتم حساب مؤشرات مهمة في علم المعرفة المحلية للنباتات بما في ذلك اختبار اجماع الناس على استخدام معين (ICF)، ومستوى الدقة في اشتغلال نبات معين لاشتخدام معين (FL٪).&nbsp;النتائج: أظهرت نتائج DCA أن هناك نوعا من النباتات الشائعة التي تم جمعها من نوع ثلاثة الغابات بشكل مكثف على سبيل المثال الزعتر البري Origanum syriacum L. ، الخبيزة Malva parviflora L. و اللوف Arum palaestinum Boiss. وأن هنالك بعض الأنواع النباتية تم جمعها من نوع معين من الغابات. كما وتم الأجماع من قبل العينه من السكان المحلين بأن الاستخدام الرئيسي للنباتات المحلية هو الغذاء ومن ثم الغذاء والدواء.&nbsp;الاستنتاج : بناء على نتائج الدراسة ، يقترح أن تأخذ في الاعتبار سلوك جمع الناس للنباتات الحرجية المحلية االموجودة في نظام الغابات البيئي الهش قي برامج الحفاظ على النظام الإيكولوجي على أساس اشراك السكان المحليون من أجل تحقيق الاستدامة البيئية و منع انجراف التنوع البيولوجي.&nbsp;Understanding the distribution and floristic features of native forest plants, as well as the reasons that lead local people to collect them, is of great value for planning and implementing forest conservation and rehabilitation projects in the Mediterranean forest involving local communities. The aims of this study were to (1) investigate the distribution pattern, (2) analyze the floristic features, and (3) investigate the main uses of plants gathered from three Mediterranean forest ecosystems in Northern Jordan. We sampled 14 villages that were selected according to their location on the edge and within the three Mediterranean forest types in Northern Jordan. Three hundred informants were interviewed face to face using a semi-structured questionnaire. The data obtained included a list of plants collected and their uses. A Detrended Correspondence Analysis (DCA) was carried out to investigate the distribution of plant species collected from the three forest types. Also, important indices were calculated including Informant Consensus Factor (ICF), Fidelity Level (FL%), and uses totaled. The DCA showed that there are common plant species gathered intensively from all three forest types, namely Origanum syriacum L., Malva parviflora L., and Arum palaestinum Boiss., and that some plant species are collected from a particular forest type. The main uses of the collected plants are food and medicine. The study results suggest value in taking into account the behavior of people who collect native forest plants when designing fragile forest ecosystem restoration programs. These programs should be community-based in order to achieve ecosystem sustainability and prevent biodiversity erosion.

Topography influences the distribution of autumn frost damage on trees in a Mediterranean-type Eucalyptus forest

Extreme temperatures are causing forest dieback in a Mediterranean-type forest. Topography and cold-air pooling explain the geographic distribution of frost dieback in susceptible tree species. Alterations to the frequency and intensity of extreme temperatures, predicted with climate change, pose a threat to the health of many forests. Some Mediterranean climate regions are experiencing higher temperature variability, including more extreme low and high temperature events. Following one such low-temperature event in autumn 2012, we conducted landscape- and site-level studies to examine the impact of frost on trees and the interaction between topography, temperature, and dieback in a forest ecosystem in the Mediterranean climate region of southwest Australia. Canopy damage was widespread across the survey area and occurred in distinct patches, with sizes ranging between 4.1 and 2,518.0 ha. In affected forest, Eucalyptus marginata and Corymbia calophylla experienced nearly complete crown dieback, while E. patens and E. wandoo were undamaged. Canopy damage was found more frequently in valleys and lower to mid-slope positions, and site-level studies confirmed that crown dieback generally increased with decreasing elevation. Low temperatures were strongly correlated with elevation along damaged forest transects and cold-air pooling explained the pattern of forest damage. By regressing temperatures from damaged sites against those collected from the nearest meteorological station, projected minimum air temperatures ranged from −0.1 to −2.7 °C at valley bottom when the dieback occurred. Insufficient tissue hardening is suspected to have predisposed trees to this autumn frost. The interaction between shifting temperature regimes with climate change and frost damage is discussed. With continued increases in temperature variability, we can expect to see more temperature-driven disturbance events and associated reductions in forest health.

Soil nutrients and microbial biomass in three contrasting Mediterranean forests

The extent to which the spatial and temporal patterns of soil microbial and available nutrient pools hold across different Mediterranean forest types is unclear impeding the generalization needed to consolidate our understanding on Mediterranean ecosystems functioning. We explored the response of soil microbial, total, organic and inorganic extractable nutrient pools (C, N and P) to common sources of variability, namely habitat (tree cover), soil depth and season (summer drought), in three contrasting Mediterranean forest types: a Quercus ilex open woodland, a mixed Q. suber and Q. canariensis woodland and a Pinus sylvestris forest. Soil microbial and available nutrient pools were larger beneath tree cover than in open areas in both oak woodlands whereas the opposite trend was found in the pine forest. The greatest differences in soil properties between habitat types were found in the open woodland. Season (drought effect) was the main driver of variability in the pine forest and was related to a loss of microbial nutrients (up to 75 % loss of Nmic and Pmic) and an increase in microbial ratios (Cmic/Nmic, Cmic/Pmic) from Spring to Summer in all sites. Nutrient pools consistently decreased with soil depth, with microbial C, N and P in the top soil being up to 208 %, 215 % and 274 % larger than in the deeper soil respectively. Similar patterns of variation emerged in relation to season and soil depth across the three forest types whereas the direction and magnitude of the habitat (tree cover) effect was site-dependent, possibly related to the differences in tree species composition and forest structure, and thus in the quality and distribution of the litter input.

Fermentative Hydrogen Production from Carob Pod: A Typical Mediterranean Forest Fruit

The carob-tree (Ceratonica siliqua L.) grows in arid to semi-arid Mediterranean areas and adapts well to poor soils. Carob pod, the fruit of carob tree is a sugar-rich biomass which may theoretically be ideal for biofuel production. During this study, the potential of hydrogen production from carob pod was evaluated in an anaerobic continuous stirred tank bioreactor using mixed microflora. A carob pod extract consisting of soluble carbohydrates at a concentration of 42.6 g/L was obtained from a standard extraction process. The reactor was operated at a hydraulic retention time (HRT) of 36 and 18 h and an organic loading rate of 155.8 and 311.6 mmol glucose/L/days respectively. The results showed a maximum hydrogen production yield of 8.4 L H2 per kg of carob pod biomass or 0.43 mmol H2 per mmol glucose consumed at the HRT of 18 h. Butyric acid was found to be the dominant metabolic product at both examined HRTs while propionic acid production decreased as HRT decreased. The present work suggests that carob tree, an alternative dryland forest crop, can be utilized for the efficient production of biohydrogen.

Inventory and characterization of traditional Mediterranean pig production systems. Advantages and constraints towards its development

Traditional high-quality meat products from Mediterranean pigs are produced in extensive-type production systems using agro-sylvo-pastoral resources. These production systems depend on a number of native resources, geological, plants and animals. These farms have extensive areas of land, using local breeds, valorise the regional agroforests and develop the practice of grazing, use less external inputs and less manpower. In this work different issues of traditional Mediterranean pig production systems are characterized and through a SWOT methodological approach (Strengths, Weaknesses, Opportunities, Threats), we discuss the main advantages and disadvantages from the point of view of sustainability and future of the traditional Mediterranean pig meat chain. Benefits: these products have a high gastronomic and economic value that the consumer values for its unique quality and environmental gains, cultural and ethical advantage; typical Mediterranean hams and sausages are recognized internationally; they present organoleptic qualities and unique dietary feature; there are protective mechanisms and quality control that allow defending the genuineness of the products (PDO, PGI). Constraints: it is common to find weaknesses at the farm management level and animal husbandry, and there are also serious threats related to natural resource management (degradation of the typical Mediterranean forest) and market competitiveness. The sustainability of Mediterranean traditional pig industry depends on the preservation of endogenous resources and the quality of management at the farm level, as well as the market transparency.

Assessing temporal variation of primary and ecosystem production in two Mediterranean forests using a modified 3-PG model

& Context Forest ecosystem carbon uptake is heavily affected by increasing drought in the Mediterranean region. & Aims The objectivesofthisstudy weretoassessthe capacity of a modified 3-PG model to capture temporal variation in gross primary productivity (GPP), and ecosystem net carbon uptake (NEE) in two Mediterranean forest types. & Methods The model was upgraded from a monthly (3-PG) to a daily time step (3-PGday), and a soil water balance routine was included to better represent soil water availability. The model was evaluated against seasonal GPP and NEE dynamics from eddy covariance measurements. & Results Simulated and measured soil water content values were congruent throughout the study period for both forest types. 3-PGday effectively described the following: GPP and NEE seasonal patterns; the transition of forest ecosystems from carbon sink to carbon source; however, the model overestimated diurnal ecosystem respiration values and failed to predict ecosystem respiration peaks. & Conclusions The model served as a rather effective tool to represent seasonal variation in gross primary productivity, and ecosystem net carbon uptake under Mediterranean droughtprone conditions. However, its semi-empirical nature and the simplicity inherent in the original model formulation are obstaclespreventingthemodel workingwellfor short-termdaily predictions.

Sudden forest canopy collapse corresponding with extreme drought and heat in a mediterranean-type eucalypt forest in southwestern Australia

Drought and heat-induced forest dieback and mortality are emerging global concerns. Although Mediterranean-type forest (MTF) ecosystems are considered to be resilient to drought and other disturbances, we observed a sudden and unprecedented forest collapse in a MTF in Western Australia corresponding with record dry and heat conditions in 2010/2011. An aerial survey and subsequent field investigation were undertaken to examine: the incidence and severity of canopy dieback and stem mortality, associations between canopy health and stand-related factors as well as tree species response. Canopy mortality was found to be concentrated in distinct patches, representing 1.5 % of the aerial sample (1,350 ha). Within these patches, 74 % of all measured stems (>1 cm DBHOB) had dying or recently killed crowns, leading to 26 % stem mortality six months following the collapse. Patches of canopy collapse were more densely stocked with the dominant species, Eucalyptus marginata, and lacked the prominent midstorey species Banksia grandis, compared to the surrounding forest. A differential response to the disturbance was observed among co-occurring tree species, which suggests contrasting strategies for coping with extreme water stress. These results suggest that MTFs, once thought to be resilient to climate change, are susceptible to sudden and severe forest collapse when key thresholds have been reached.

Effect of wildfires on soil respiration in three typical Mediterranean forest ecosystems in Madrid, Spain

Mediterranean forests are vulnerable to numerous threats including wildfires due to a combination of climatic factors and increased urbanization. In addition, increased temperatures and summer drought lead to increased risk of forest fires as a result of climate change. This may have important consequences for C dynamics and balance in these ecosystems. Soil respiration was measured over 2 successive years in Holm oak (Quercus ilex subsp. ballota; Qi); Pyrenean Oak (Quercus pyrenaica Willd; Qp); and Scots pine (Pinus sylvestris L.; Ps) forest stands located in the area surrounding Madrid (Spain), to assess the long term effects of wildfires on C efflux from the soil, soil properties, and the role of soil temperature and soil moisture in the variation of soil respiration. Soil respiration, soil temperature, soil moisture, fine root mass, microbial biomass, biological and chemical soil parameters were compared between non burned (NB) and burned sites (B). The annual C losses through soil respiration from NB sites in Qi, Qp and Ps were 790, 1010, 1380 gCm−2 yr−1, respectively, with the B sites emitting 43 %, 22 % and 11 % less in Qi, Qp and Ps respectively. Soil microclimate changed with higher soil temperature and lower soil moisture in B sites after fire. Exchangeable cations and the pH also decreased. The total SOC stocks were not significantly altered, but 6–8 years after wildfires, there was still measurably lower fine root and microbial biomass, while SOC quality changed, indicated by lower the C/N ratio and the labile carbon and a relative increase in refractory SOC forms, which resulted in lower Q10 values. We found long term effects of wildfires on the physical, chemical and biological soil characteristics, which in turn affected soil respiration. The response of soil respiration to temperature was controlled by moisture and changed with ecosystem type, season, and between B and NB sites. Lower post-burn Q10 integrated the loss of roots and microbial biomass, change in SOC quality and a decrease in soil moisture.