Cork Oak Quercus Suber Research Articles

Breeding ecology of the endangered Algerian Nuthatch (Sitta ledanti) endemic to the Babors′ Kabylia (Northeastern Algeria): Implications of conservation

Abstract The endemic Algerian Nuthatch Sitta ledanti, is classified as an endangered species by the IUCN and protected species by Algerian law. Available information on its nesting and breeding biology is sporadic and incomplete, the purpose of which is to provide additional data on the different aspects of multi-site nesting of the species. 22 nests are monitored across five forests, during the nesting season of 2021. An endoscopic camera was used to monitor eggs and nestlings in the nests during the whole study. Most of the nests (n = 20) were constructed in different parts of the dead trees such as trunks or branches of the Atlas cedar Cedrus atlantica, the Algerian oak Quercus canariensis, the African oak Quercus afares or Cork oak Quercus suber. The laying dates were from early April to the end of May when April 28 (± 13 days) is the laying season’s median start date. The average clutch size was 4.6 (n = 21). The mean hatching success was 89.2%, while mean fledging success was 88.2%. The nestling sex ratio was 14 males versus 18 females. Data on clutch dates and fecundity of breeding pairs should be considered in any conservation approach and strategy in the context of habitat management and preservation.

Novel Sustainable Alternatives for the Study of the Chemical Composition of Cork

Cork is a natural and renewable material extracted from the cork oak Quercus suber L. (1) Background: The cellular structure and chemical composition of the plant wall give cork its physical and mechanical properties. Chemically, the composition of cork is principally dominated by the presence of suberin as the main structural cell wall component and affected by its close association with other components. The usual chemical analysis of cork has been partially adapted from wood and other lignocellulosic analytical methods and it is a method with extensive procedures. This study aims to (i) find quicker and more sustainable methods for testing the cork chemical composition, (ii) conduct extraction tests using alternative techniques, (iii) optimize alternative methodologies, and (iv) validate the proposed sustainable methodologies. (2) Methods: Microwave-assisted extraction (MAE) and accelerated solvent extraction (ASE) are explored as alternative systems to the traditional method. The percentages of the extractives obtained via MAE are lower than the percentages obtained by means of the classical composition. (3) Results: However, the percentages of suberin are very similar in both methods: 46.39% in the case of the classical composition and 45.11% in the case of microwave-assisted extraction. No significant differences are observed between the content of the extractives in the dichloromethane, ethanol, and water obtained via ASE and the results obtained with the classical methodology. (4) Conclusions: MAE and ASE are faster methods; they use less solvents and provide more reproducible results than the classical chemical composition methodology. These data pave the way for novel sustainable alternatives relative to the studies of the chemical composition of cork.

Suberin, the hallmark constituent of bark, identified in a 45-million-year-old monkeyhair tree (Coumoxylon hartigii) from Geiseltal, Germany.

Suberin, a complex biopolymer, forms a water- and gas-insoluble barrier that protects the inner tissues of plants. It is abundant in tree bark, particularly in the cork oak Quercus suber. Anatomically, fossil bark has been described since the Devonian. However, its distinctive constituent suberin has not yet been reported from the fossil record. Here we present unambiguous chemical evidence for intact suberin from the bark of a middle Eocene monkeyhair tree from Geiseltal, eastern Germany. High-performance liquid chromatography coupled to electrospray ionization mass spectrometry (HPLC-ESI-MS) detected constituents of suberin in the outer layer the fossil monkeyhair tree, which confirms previous morphological interpretation of this tissue as bark, and chemically differentiates this layer from the two tissues of the inner layer. Notably, this is the first study with compelling chemical evidence for suberin in fossil bark. Fluorescence microspectroscopy additionally supports the presence of suberin. Fossilization conditions in the Eocene Geiseltal deposit were likely mild, with low moisture and temperatures, contributing to the remarkable preservation of bark and inner laticifer mats of the monkeyhair trees growing there 45 million years ago.

Radicle length and container size effects on root deformities in the Mediterranean oak <i>Quercus suber</i> L.

The aim of this study was to assess the effects on root deformations in Mediterranean cork oaks Quercus suber L. of container size and radicle length at the time of sowing. Acorns at five sowing methods – intact acorns, acorns that had germinated during storage, acorns that had germinated after moist stratification and acorns with radicles (R) less than 5 mm in length, 7 mm to 12 mm in length and more than 15 mm length – were planted individually in WM type containers of 400 cm3, 800 cm3 and 1,200 cm3. At the end of the nursery growth period, the roots of the 1,080 sampled seedlings were examined for root deformities. The experiment results showed that root deformation affected almost half (49%) of the container-grown cork oak seedlings and that the germination status of acorns at the time of planting had a significant effect on root deformations, whereas container volume had no clear effect. The largest number of deformed roots (91%) was observed in seedlings grown from germinated acorns, as compared to 9% of seedlings grown from intact acorns. Planting germinated acorns with radicles 15 < R < 20 mm and 7 < R < 12 mm in length produced the highest percentages of detrimental deformations. Irrespective of size, the bottomless WM container type was shown to be highly effective against the root spiralling frequently observed in closed cylindrical polyethylene bags. The results of this study could help to improve cork oak seedling quality for more successful reforestation programs.

The influence of management and environmental factors on insect attack on cork oak canopy

The decline of oak (Quercus spp.) forests is a current trend in Northern Hemisphere and is characterized by a loss in tree vigour and increased mortality. The canopy insects are suspected to have role in this decline, but there is poor knowledge about their incidence in evergreen-oak stands. The main aim of this study is to characterize the incidence of main insect groups affecting branches and leaves of an evergreen-oak species (the cork oak Quercus suber) and evaluate which management practices and environmental traits of agroforestry systems affect it. In the spring/summer of 2018, we measured the incidence of attacks on branches and leaves by gall-makers (Diptera, Cecidomyiidae), blade-miners (Lepidoptera and Coleoptera), midrib-miners (Lepidoptera, Heliozelidae), chewer caterpillars (Lepidoptera), chewer sawflies (Hymenoptera, Tenthredinidae), weevils (Coleoptera, Curculionidae) and branch-borers (Coleoptera, Buprestidae). We analysed the frequency of pest signs according to different indicators: management practices, tree maturity, forest diversity, forest fragmentation, and latitude and longitude. The most frequent signs of insect pests on tree leaves corresponded to blade-miners, midrib-miners, chewer caterpillars and chewer sawflies. With exception of midrib-miners and branch-borers, all insect pests were found on cork oak stands experiencing decline and benefited from management intensification. Our study suggests that a diverse-aged stand may reduce the frequency of midrib-miners and chewer caterpillars, as well the attack of branch-borers. Moreover, a high plant diversity in forests can contribute to reduce the impact of defoliators on cork oaks (e.g., chewer sawflies) and understory reduction decreased the exposure of trees to gall-makers. Moreover, we found that forest fragmentation may increase the frequency of blade-miners and chewer caterpillars. We conclude that insect pests have a high incidence in cork oak stands and thus, may have and important role in its decline. Considering that a high frequency of pests is often associated with increased management intensity, a change to a more sustainable use of these systems is urgently needed.

Site- and tree-related factors affecting colonization of cork oaks Quercus suber L. by ambrosia beetles in Tunisia

Ambrosia beetles are emerging globally as important agents of tree death and decline. In this work, we observed highly variable attack intensity by ambrosia beetles in cork oak stands in Tunisia. A correlation between the proportion of infested trees and average temperature was found. Tree diameter and tree phytosanitary variables further contribute to the attack densities of ambrosia beetles. Results can be relevant for preventive measures aiming to conserve this natural forest heritage. Cork oak woodlands comprise a unique Mediterranean ecosystem supporting rich biological diversity and providing multiple services. A decline of cork oak forests has been observed in several regions of the Mediterranean Basin in the last four decades, which can be related to climate change, novel biotic agents, and changes in management practices. The ambrosia beetles have been one of the major biotic agents associated with cork oak decline, mostly in the western Mediterranean. Assess the presence and attack densities of ambrosia beetles in cork oak Tunisian forests. A total of 15 sites located in North Western of Tunisia, comprising 729 sample trees were evaluated. Using generalized linear models, the presence and density of ambrosia beetles’ holes were related to tree and site variables. Variables related to climate, tree (dendrometric parameters, debarking intensity) and biotic agents were examined. The proportion of trees attacked per site varied from 0 to 100%; in four sites, it exceeded 50%. At the site level, the average temperature and tree diameter were the main variables explaining the proportion of attacked trees. Sites with warmer climates showed higher incidence of ambrosia beetles. At the tree level, the presence of attacks increased with tree diameter and concomitantly with intensity of debarking, as well as the presence of tree trunk cavities. The presence and density of insect attacks were related to tree diameter, area of debarking, and phytosanitary conditions. However, 19% of the trees attacked by ambrosia beetles had no signs of other biotic agents or decline. At the site level, attack rates increased with temperature and tree diameter. A warmer climate may change insect behavior from that of a non-aggressive pest to that of an aggressive bark beetle. Adaptive forest management practices are needed to reduce infestations.

Conservation and restoration strategies to preserve the variability of cork oak Quercus suber—a Mediterranean forest species—under global warming

CR Climate Research Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsSpecials CR 71:171-185 (2016) - DOI: https://doi.org/10.3354/cr01440 Conservation and restoration strategies to preserve the variability of cork oak Quercus suber-a Mediterranean forest species-under global warming Bartolomeo Schirone1,*, Kalliopi Radoglou2, Federico Vessella1 1Department of Agriculture and Forestry (DAFNE), Università degli Studi della Tuscia, via San Camillo de Lellis, snc, 01100 Viterbo, Italy 2Department of Forestry and Management of the Environment and Natural Resources, Democritus University of Thrace (DUTH), Pantazidou 193, P.C. 68200 N. Orestiada, Greece *Corresponding author: schirone@unitus.it ABSTRACT: Climate change effects on forest ecosystems are a matter of debate within the scientific community, given their implications for biodiversity conservation and management. Coupling environmental data and modelling techniques with new advances on species resistance to disturbances, resilience, and new potential colonization areas provides insights that can used in rehabilitation, reconstruction, reclamation, and replacement. Here, we investigated an economically relevant evergreen oak, Quercus suber L. that is naturally distributed in the central-western Mediterranean Basin. Ecological niche modeling (ENM) was applied to statistically forecast the suitability areas of 4 haplotypes, as detected in previous studies. Combining these results with past reconstructions of climatically favourable regions, we identified 22 putative refugia and their climate characteristics that could host cork oak haplotypes. Different responses were observed among haplotypes: some of them were foreseen to expand their range over the next century, others to retreat. Overall, coastal mountains appeared to play a crucial role in the species’ conservation. Notably, future scenarios call for a differential type of management for cork oak, considering local conditions and human disturbances. For 3 examples (Apulia, Kabylie and Peloponnese), we analyzed conservation, enrichment, localized reforestation, and assisted migration as strategies to mitigate or prevent the loss of genetic diversity and the extinction risk driven by global warming. The implementation of advanced forest nursery technologies for high quality seedling production are factors recommended for the successful preservation and extension of cork oak presence in the Mediterranean under future climate change. KEY WORDS: Quercus suber · Ecological niche modelling · Haplotype forecasting · Putative refugia · Assisted migration · Mediterranean Basin Full text in pdf format Supplementary material PreviousCite this article as: Schirone B, Radoglou K, Vessella F (2016) Conservation and restoration strategies to preserve the variability of cork oak Quercus suber-a Mediterranean forest species-under global warming. Clim Res 71:171-185. https://doi.org/10.3354/cr01440 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in CR Vol. 71, No. 2. Online publication date: December 28, 2016 Print ISSN: 0936-577X; Online ISSN: 1616-1572 Copyright © 2016 Inter-Research.

Long‐term impact of protected colonial birds on a jeopardized cork oak population: conservation bias leads to restoration failure

Summary Conservation bias towards flagship species sometimes threatens other species of chief concern. Long‐term studies of potential harm by favoured species on other sensitive species, though seldom adopted, are required to fairly evaluate the suitability of management and restoration efforts. We illustrate the potential detrimental outcomes of conservation biased towards birds by investigating the long‐term (1963–2009) impact of a large waterbird colony (up to 13 000 pairs) on a remnant cork oak Quercus suber population at a World Biosphere Reserve in south‐western Spain (the Doñana National Park). To this end, we compared changes in performance (growth, crown vigour and survival) of oaks occupied and unoccupied by the waterbird colony. After 46 years of occupation, the risk of death to centenarian oaks in the area occupied by the colony was over twofold higher than for trees outside the area. Non‐centenarian planted and naturally regenerated oaks showed similar trends, leading to restoration failure. Synthesis and applications. Our long‐term study reveals that waterbirds and centenarian oaks cannot coexist, at the most local scale, but they can at a regional scale including within the Doñana area. We propose immediate planting efforts in suitable colony‐free areas, while managers evaluate the feasibility of relocating colonial waterbirds to an alternative location. To preserve the Doñana oak genetic pool, such reforestation should be accomplished using local seeds and seedlings. New trees should not be planted in close proximity of colony‐occupied trees since it significantly reduces their survival. Doñana stakeholders should both overcome current conservation bias in favour of birds and enter into a process of settlement to best preserve the overall biodiversity of the system.

Effects of dominant tree species on insectivorous birds breeding in Mediterranean oak woodlands

Capsule Differences in Cork Oak Quercus suber and Holm Oak Quercus rotundifolia dominance had little influence on bird communities though bark-gleaners showed a foraging preference for Cork Oak.Aims Examine the use of Cork and Holm Oak trees by insectivorous birds in Mediterranean oak woodlands.Methods Point-counts were used to compare species abundance among Cork Oak-dominated, Holm Oak-dominated and mixed woodlands. Focal foraging observations were used to evaluate the use of Cork and Holm Oaks in the three habitats and to relate tree characteristics with the foraging time of foliage- and bark-gleaners.Results Bird densities in the three habitats were not different for most foliage- and bark-gleaners. Tree preference index values and foraging time per tree showed no significant differences between tree species and foraging guilds, however bark-gleaners had positive index values for Cork Oak in the three habitats. The foraging time of foliage- and bark-gleaners on both tree species showed a positive relationship with characteristics associated with arthropod abundance.Conclusion Cork and Holm Oak trees are equally preferred by foliage-gleaners but bark-gleaners moderately preferred Cork Oak. Characteristics regarding morphology, phenology and physiological condition of trees can be used to predict habitat quality for insectivorous forest birds in Mediterranean oak woodlands.

Post-release habitat utilisation by Francolinus bicalcaratus ayesha, a critically endangered subspecies endemic to Morocco: implications for optimising future release programmes

SummaryCharacterising the habitat use of released captive-bred birds is required to help optimise future avian reintroduction programmes. The critically endangered Double-spurred Francolin Francolinus bicalcaratus ayesha is endemic to north-west Morocco, where it inhabits forests of cork oak Quercus suber. To improve the viability of this threatened population, 300 captive-bred francolins were released into a game reserve, and post-release monitoring was conducted. This study aimed to identify habitat variables determining the habitat selection of the Double-spurred Francolin. Auditory detection was used during transect surveys of calling males to locate birds and their habitat occupation. Comparison of occupied and random plots showed that this bird is found mostly in flat topography with high cover of shrubs and dense cork oak trees, and close to the release site and water points. Conservation of Double-spurred Francolin depends on the choice of the release point within the cork oak forest, which should be in proximity to suitable cover of cork oak trees, shrubs and water points. Such choices would allow a rapid adaptation to prevailing conditions within release sites. Further multi-scale studies are needed to improve our understanding of the effects of ecological factors on the processes of habitat selection by this endemic subspecies.

Field trapping of the flathead oak borer Coroebus undatus (Coleoptera: Buprestidae) with different traps and volatile lures.

The flathead oak borer Coroebus undatus F. (Coleoptera: Buprestidae) is one of the primary pests of cork oak Quercus suber L. in the Mediterranean region causing great economic losses to the cork industry. Very little is known about its biology and behavior and, so far, no control measures have been established. We present the results of a pilot study aimed to develop an efficient trapping method for monitoring this harmful pest. In a 3-year field study, purple-colored prism traps baited with a mixture of green leaf volatiles (GLVs) from the host have been shown the most effective combination to catch C. undatus adults (solely females) compared to other trap and lure types tested. Wavelength and reflectance measurements revealed that purple traps exhibit reflectance peak values similar to those found in the abdominal and elytral cuticle of both sexes, suggesting the involvement of visual cues for mate location in this species. The data presented are the first to demonstrate captures of adults of the genus Coroebus by an attractant-based trapping method.

Modelling fuel succession in Mediterranean cork oak forests along a 70-year chronosequence

Mechanical removal of understory vegetation is increasingly used in Euro-Mediterranean forests to reduce fire hazard, but little is known about the long-term patterns of fuel change after management. We used a 70-year post-management chronosequence to investigate fuel succession in cork oak Quercus suber forests. Mean shrub height, crown volume, total standing biomass, and biomass of leaves, and coarse and fine materials, increased rapidly during the first 10years after management, but then converged slowly to a plateau that was not reached within the chronosequence. A high vertical continuity of fuels from the ground level to the tree canopy (0–2m) was reached in about 10–20years, but peak understory cluttering occurred only at 50–70years. Fine materials accumulated primarily at lower strata (<1m) throughout the chronosequence, whereas leaves and coarse materials accumulated first at lower strata, and then progressively occupied the upper strata (>1.5m). Results suggest that recurrent fuel management may promote highly flammable pioneer shrublands, whereas lack of management promotes late-successional vegetation with high risk of intense wildfires. Solving this conundrum requires careful planning of the spatial and temporal distribution of treatments to reduce the risk of fire spread at the landscape scale.

Distribution of Coraebus undatus (Coleoptera: Buprestidae) in cork oak forests of southern Spain

Coraebus undatus is a beetle which excavates galleries in the cork tissue, leading to important economic reductions in quantity and quality of cork that can be harvested from cork oak Quercus suber. Andalusia (southern Spain) produces around 14% of the world's cork supplies and leads the way in cork production in Spain. By analysing distribution patterns and infestation levels of C. undatus in different cork oak forests of southern Spain, useful information for implementing sustainable management of the pest can be obtained. We recorded the level of beetle infestation in cork oak forests by observing the traces left by larval galleries in trees that had recently been de-corked. Our results reveal a widespread distribution for C. undatus and a high percentage of infested oaks (>70%) in almost all cork oak forests in southern Spain. The most damaged forests were located in the areas with the highest density of cork oak forests and a dominant understory.

Time to rethink the management intensity in a Mediterranean oak woodland: the response of insectivorous birds and leaf-chewing defoliators as key groups in the forest ecosystem

The Iberian cork oak Quercus suber montados are dynamic agro-silvo-pastoral systems, contrasting with the abandonment trend of other Mediterranean forested areas. We aimed to identify the effect of management type and vegetation features on breeding insectivorous birds and leaf-chewing defoliator insects. In central Portugal, we selected two groups of 20 sites: dense montados (DM, high cover of cork oaks and low cattle impact) and sparse montados (SM, low cover of oaks and high cattle impact). We collected variables associated with vegetation features, bird community and chewing defoliators. The two systems differed significantly in oak trunk diameter, oak and shrub cover, tree and shrub diversity. Ground bird densities were higher in SM with fragmented shrub cover. In DM, higher woody vegetation cover and diversity can promote shrub birds and leaf warblers. Oak defoliation was mainly attributed to the sawfly Periclista andrei. Sawfly defoliation was significantly higher in SM and negatively correlated with shrub cover. Our results highlight (1) the relevance of management activities conducted at the shrubby layer, (2) the need of an increase in tree diversity and density and (3) the maintenance of a mosaic landscape in order to improve the bird community richness and reduce the defoliation impact in montado system.

Cork oak vulnerability to fire: the role of bark harvesting, tree characteristics and abiotic factors.

Forest ecosystems where periodical tree bark harvesting is a major economic activity may be particularly vulnerable to disturbances such as fire, since debarking usually reduces tree vigour and protection against external agents. In this paper we asked how cork oak Quercus suber trees respond after wildfires and, in particular, how bark harvesting affects post-fire tree survival and resprouting. We gathered data from 22 wildfires (4585 trees) that occurred in three southern European countries (Portugal, Spain and France), covering a wide range of conditions characteristic of Q. suber ecosystems. Post-fire tree responses (tree mortality, stem mortality and crown resprouting) were examined in relation to management and ecological factors using generalized linear mixed-effects models. Results showed that bark thickness and bark harvesting are major factors affecting resistance of Q. suber to fire. Fire vulnerability was higher for trees with thin bark (young or recently debarked individuals) and decreased with increasing bark thickness until cork was 3–4 cm thick. This bark thickness corresponds to the moment when exploited trees are debarked again, meaning that exploited trees are vulnerable to fire during a longer period. Exploited trees were also more likely to be top-killed than unexploited trees, even for the same bark thickness. Additionally, vulnerability to fire increased with burn severity and with tree diameter, and was higher in trees burned in early summer or located in drier south-facing aspects. We provided tree response models useful to help estimating the impact of fire and to support management decisions. The results suggested that an appropriate management of surface fuels and changes in the bark harvesting regime (e.g. debarking coexisting trees in different years or increasing the harvesting cycle) would decrease vulnerability to fire and contribute to the conservation of cork oak ecosystems.

Long‐term responses of Mediterranean birds to forest fuel management

Summary1. Mechanical management of forest fuels is increasingly used in the Euro‐Mediterranean region in response to the abandonment of traditional agroforestry and the concurrent increase in fire hazard. Although fuel management may have positive side effects for biodiversity, its long‐term impacts remain largely unknown.2. We used a 70‐year post‐management chronosequence to investigate the influence of time since fuel management and management frequency on bird assemblages in cork oak Quercus suber forests.3. Fuel management strongly affected bird species richness, abundances and assemblage composition, with rapid changes often occurring during the first 10–20 years, followed in the next decades by a slow convergence to pre‐management levels.4. In winter, overall species richness and abundance, and that of frugivores and shrub foragers, were negatively affected by recent and recurrent management, only recovering in stands unmanaged for &gt;50 years. In spring, insectivore abundance and the richness and abundance of shrub foragers declined immediately following management, increased to a maximum about 20 years later, and declined thereafter. Breeding granivores and ground foragers were the only groups that benefitted from fuel management. There were no overall effects on species of conservation concern, although a few species with unfavourable status benefitted from fuel management.5. Synthesis and applications. Our study confirmed that mechanical fuel management has positive effects on some early‐successional bird species of conservation concern, although its effects were limited. These benefits should be compared with the strong negative impacts on key bird species such as wintering frugivores, which play a pivotal role in ecosystems by promoting seed dispersal. To reconcile the positive and negative aspects, fuel management should be used to create heterogeneous mosaics of forest patches encompassing a range of sizes (10–100 ha) and successional stages of understorey vegetation, including stands undisturbed for &gt;50 years. This management strategy will likely maintain conditions for a wide range of species with contrasting ecological requirements while also reducing fire hazard.

Impact of cork extraction on birds: Relevance for conservation of Mediterranean biodiversity

Montados are Mediterranean agro-forestry-pastoral systems recognized as an excellent example of balance between socio-economic development and biodiversity conservation. The economic viability of montados dominated by cork oak Quercus suber depends on the extraction of cork (the bark of trees), usually in 9 year cycles, which is mostly used for production of bottle stoppers. This study evaluated the impact of cork extraction on biodiversity, using birds as indicators. Comparing bird assemblages of areas with recently extracted cork and older cork revealed that only two species of bark gleaners and two of bark-foliage gleaners had lower densities in recently debarked areas. Arthropod sampling revealed that, in the first years after cork extraction, the bark has less prey, suggesting that the reduction in bark gleaners densities is a result of the decreased food availability. Focal observations confirmed that the affected species were those that foraged mostly on cork. However, our data demonstrated that bird richness and the density of the majority of species were unaffected by debarking, and that at the landscape level even bark gleaners had potentially stable populations. Pressure from the synthetic bottle stopper industry threatens to render montados economically unviable, and consequently be replaced by land uses much less valuable for biodiversity. Showing that cork extraction is compatible with the maintenance of the great ornithological value of montados, our results confirm that it is an economic activity that should be promoted for the benefit of biodiversity.

Phenotypic plasticity and local adaptation in leaf ecophysiological traits of 13 contrasting cork oak populations under different water availabilities

Plants distributed across a wide range of environmental conditions are submitted to differential selective pressures. Long-term selection can lead to the development of adaptations to the local environment, generating ecotypic differentiation. Additionally, plant species can cope with this environmental variability by phenotypic plasticity. In this study, we examine the importance of both processes in coping with environmental heterogeneity in the Mediterranean sclerophyllous cork oak Quercus suber. For this purpose, we measured growth and key functional traits at the leaf level in 9-year-old plants across 2 years of contrasting precipitation (2005 and 2006) in a common garden. Plants were grown from acorns originated from 13 populations spanning a wide range of climates along the distribution range of the species. The traits measured were: leaf size (LS), specific leaf area (SLA), carbon isotope discrimination (Delta(13)C) and leaf nitrogen content per unit mass (N(mass)). Inter-population differences in LS, SLA and Delta(13)C were found. These differences were associated with rainfall and temperature at the sites of origin, suggesting local adaptation in response to diverging climates. Additionally, SLA and LS exhibited positive responses to the increase in annual rainfall. Year effect explained 28% of the total phenotypic variance in LS and 2.7% in SLA. There was a significant genotype x environment interaction for shoot growth and a phenotypic correlation between the difference in shoot growth among years and the annual mean temperature at origin. This suggests that populations originating from warm sites can benefit more from wet conditions than populations from cool sites. Finally, we investigated the relationships between functional traits and aboveground growth by several regression models. Our results showed that plants with lower SLA presented larger aboveground growth in a dry year and plants with larger leaf sizes displayed larger growth rates in both years. Overall, the study supports the adaptive value of SLA and LS for cork oak under a Mediterranean climate and their potentially important role for dealing with varying temperature and rainfall regimes through both local adaptation and phenotypic plasticity.

The foraging ecology of red deer (Cervus elaphus) in a Mediterranean environment: is a larger body size advantageous?

AbstractIn Mediterranean environments browse is expected to be a major component of the diet of red deer Cervus elaphus during the summer when most grasses senesce. In this study the hypothesis is tested that, if browse is an essential food resource at this time, the sex with the larger body size may have a greater physical ability to reach the tree canopy and include a higher proportion of browse in its diet. The organic matter digestibility (OMD) and composition of the diet of a population of red deer males and females were measured between July and September, in 1996 and 1997, in an area of Portugal with a Mediterranean type of climate, using the n‐alkane technique. Direct observations of animals browsing on tree canopies and shrubs were made also during the same period. The OMD of the diet was significantly different between sexes and between years and was higher in males than females both in 1996 (means ±sem for males and females, 0.65 and 0.58 ± 0.026, respectively) and 1997 (means for males and females, 0.59 and 0.48 ± 0.045, respectively). The proportion of cork oak Quercus suber in the diet was also significantly different between sexes and between years, with males having a higher proportion of cork oak in their diets in 1996 (males and females, 0.30 and 0.16 ± 0.037, respectively) and 1997 (males and females, 0.41 and 0.23 ± 0.064, respectively). A significantly lower proportion of the herbage layer was found in the diet of males in 1996 (males and females, 0.46 and 0.64 ± 0.048) but not in 1997. The number of observations of males browsing on tree canopies was significantly higher than females. It is concluded that there are differences between sexes in the composition and quality of the diet and that a larger body size may confer advantages in situations where browse is an essential food resource.

Nesting habitat selection by booted eagles Hieraaetus pennatus and implications for management

Summary 1. The booted eagle Hieraaetus pennatus is a poorly known and scarce raptor that breeds in Spain. In Doñana National Park (south‐west Spain) its population has increased from only six breeding pairs in the early 1980s to about 150 today. 2. In order to guide habitat management for this raptor in Doñana National Park, we related nesting habitat selection to breeding success. 3. Birds withstood some human disturbance when nesting, choosing sites closer to pastures besides marshes, footpaths and crops than would occur in a random distribution. Birds also selected areas near to marsh and stands of cork oak Quercus suber. 4. Trees used for nesting were wider and taller than would occur at random. They were usually in small groups or were large isolated trees, typically eucalyptus (Eucaliptus spp.). 5. The most productive nests were close to marshland and stone pine trees Pinus pinea. 6. Habitat management to improve the breeding success of booted eagles in Doñana should include: (i) retaining small groups of trees or large isolated trees, especially eucalyptus and cork oaks close to marshland, isolated buildings and crops; (ii) creating clearings in stone pine plantations; (iii) burying potentially dangerous power lines to reduce collision risks; (iv) clearing some areas of scrubland to increase the rabbit population; and (v) controlling forest activities, especially in the breeding season. 7. The increase in booted eagle populations in western Europe during recent decades may be a consequence of the species’ capacity to adapt to environmental change. Deforestation policies designed to favour agricultural use implemented during the second half of the 20th century have not had a detrimental effect on this raptor. 8. Our work demonstrates how scarce and important organisms can be favoured by sensitive management in forestry and agricultural habitats.