Forest In Central Spain Research Articles

Linking functional composition moments of the sub-Mediterranean ecotone with environmental drivers.

Functional trait-based approaches are extensively applied to the study of mechanisms governing community assembly along environmental gradients. These approaches have been classically based on studying differences in mean values among species, but there is increasing recognition that alternative metrics of trait distributions should be considered to decipher the mechanisms determining community assembly and species coexistence. Under this framework, the main aim of this study is to unravel the effects of environmental conditions as drivers of plant community assembly in sub-Mediterranean ecotones. We set 60 plots in six plant communities of a sub-Mediterranean forest in Central Spain, and measured key above- and belowground functional traits in 411 individuals belonging to 19 species, along with abiotic variables. We calculated community-weighted mean (CWM), skewness (CWS) and kurtosis (CWK) of three plant dimensions, and used maximum likelihood techniques to analyze how variation in these functional community traits was driven by abiotic factors. Additionally, we estimated the relative contribution of intraspecific trait variability and species turnover to variation in CWM. The first three axes of variation of the principal component analyses were related to three main plant ecological dimensions: Leaf Economics Spectrum, Root Economics Spectrum and plant hydraulic architecture, respectively. Type of community was the most important factor determining differences in the functional structure among communities, as compared to the role of abiotic variables. We found strong differences among communities in their CWMs in line with their biogeographic origin (Eurosiberian vs Mediterranean), while differences in CWS and CWK indicate different trends in the functional structure among communities and the coexistence of different functional strategies, respectively. Moreover, changes in functional composition were primarily due to intraspecific variability. We observed a high number of strategies in the forest with the different communities spreading along the acquisitive-conservative axis of resource-use, partly matching their Eurosiberian-Mediterranean nature, respectively. Intraspecific trait variability, rather than species turnover, stood as the most relevant factor when analyzing functional changes and assembly patterns among communities. Altogether, our data support the notion that ecotones are ecosystems where relatively minor environmental shifts may result in changes in plant and functional composition.

Implications of forest management on the conservation of protected areas: A new proposal in Central Spain

Multifunctional forest management is a strategy increasingly shared by forest managers. In the drive towards multifunctionality, different policies are widely being developed to integrate timber production and biodiversity conservation into forest management. To achieve this aim, both segregated and integrated approaches have been used. Segregated approaches aim to provide different ecosystem services (ES) separately in stratified forest areas based on land-use zoning, whereas integrated or integrative approaches promote land-use sharing management. This type of approach has also led to the design of close-to-nature silvicultural alternatives, where different ES can be satisfied simultaneously. In the context of this new paradigm, we carried out a study to compare segregated versus integrated management strategies in Valsaín forest in Central Spain. Part of Valsaín forest was declared a protected area in 2013 and the whole forest could be declared a National Park in 50 years’ time. For the purposes of the study, we analyzed new biodiversity indicators and compared them to the traditional forest management indicators. The scenario modelling was resolved using Multi-Criteria Decision-Making techniques. Our results showed greater trade-offs between the two types of indicators when considering the forest as a whole rather than a zoning approach. Therefore, a shift from segregated to integrated management will be proposed once the whole area of Valsaín forest is declared as National Park.

Native egg parasitoids on Leptoglossus occidentalis Heidemann (Hemiptera: Coreidae) in Spain: Potential biological control agents?

AbstractLeptoglossus occidentalis Heidemann (Heteroptera: Coreidae), commonly known as western conifer seed bug (WCSB), is an invasive pest in the Mediterranean, where it has been associated with the decline of Pinus pinea L. kernel production. A biological control of WCSB populations with native egg parasitoids may reduce economic losses. With the purpose to obtaining egg masses laid in situ bags with WCSB, adults were placed, for three consecutive years, in a clone bank, and for 1 year, in a pine forest in Central Spain. To estimate the impact of the parasitoid species on the WCSB population, four parasitism indexes were calculated. The WCSB activity period was estimated for two consecutive years in the clone bank through visual monitoring. Two native parasitoid species were found on the WCSB eggs: Ooencyrtus pityocampae (Mercet) (Hymenoptera: Encyrtidae) and Ooencyrtus obscurus (Mercet) (Hymenoptera: Encyrtidae). The latter parasitoid species represents a new finding for WCSB eggs. In the clone bank, discovery efficiency of the egg masses, parasitism rate of the eggs, impact on host population and exploitation efficiency of the egg masses were significantly higher for O. obscurus than for O. pityocampae. In the pine forest, parasitism index values were also higher for O. obscurus, but significant differences were not found by species. Ooencyrtus obscurus reduced the WCSB population by 6.2%, down to 19.6%, while O. pityocampae reduced it by 1.0%, down to 11.5%. Predated eggs were recorded in both experimental sites in low amounts. Both native parasitoid species could be proposed as biological control agents (BCA) in a biological control programme (BCP) in Europe after measuring their effectiveness with laboratory assessments.

Resilience as a Moving Target: An Evaluation of Last Century Management Strategies in a Dry-Edge Maritime Pine Ecosystem

Forests are intrinsically coupled to human dynamics, both temporally and spatially. This evolution is conditioned by global changes in climatic conditions (teleconnections) and distant socio-economical processes (telecoupling). The main goal of this study is to describe the teleconnections and telecoupling dynamics that have shaped structure and processes in a dry-edge—highly vulnerable to desertification—Mediterranean pine forest during the last century and to evaluate the contribution of historical management strategies to this coupled human and natural system’s (CHANS) overall resilience. For this study, we collected relevant human and natural system data from a dry edge Pinus pinaster Ait. located forest in Central Spain using a CHANS analytical framework operationalizing telecoupling and teleconnection. A key extractive economic activity in the studied forest was resin tapping, which was the main form of land use from the 1920s to the 1950s. Since the 1950s changes in the Spanish economy linked to the emergence of new resin-producing countries, such as China, led to a sharp decline in resin production. Despite additional human system transformations affecting forest governance (e.g., the Spanish Civil War, the transition to democracy, European integration, etc.) and changes in biophysical conditions linked to climate change (e.g., aridification, CO2 fertilization), the standing stocks of P. pinaster increased during the monitoring period due to sound technical and management planning bolstering overall resilience. These historical management decisions, we argue, successfully reconciled overall resilience goals (defined as the maintenance of forest function beyond and desertification avoidance) with three successive historical forest use challenges: intensive firewood collection by local communities in fragile sandy soils, extensive pastoralism in the forest understory and tradeoffs between resin tapping damaged trees, timber production and tree cover as well as the emerging risks of wildfire and climate change.

Comparative Metagenomics of Palearctic and Neotropical Avian Cloacal Viromes Reveal Geographic Bias in Virus Discovery.

Our understanding about viruses carried by wild animals is still scarce. The viral diversity of wildlife may be best described with discovery-driven approaches to the study of viral diversity that broaden research efforts towards non-canonical hosts and remote geographic regions. Birds have been key organisms in the transmission of viruses causing important diseases, and wild birds are threatened by viral spillovers associated with human activities. However, our knowledge of the avian virome may be biased towards poultry and highly pathogenic diseases. We describe and compare the fecal virome of two passerine-dominated bird assemblages sampled in a remote Neotropical rainforest in French Guiana (Nouragues Natural Reserve) and a Mediterranean forest in central Spain (La Herrería). We used metagenomic data to quantify the degree of functional and genetic novelty of viruses recovered by examining if the similarity of the contigs we obtained to reference sequences differed between both locations. In general, contigs from Nouragues were significantly less similar to viruses in databases than contigs from La Herrería using Blastn but not for Blastx, suggesting that pristine regions harbor a yet unknown viral diversity with genetically more singular viruses than more studied areas. Additionally, we describe putative novel viruses of the families Picornaviridae, Reoviridae and Hepeviridae. These results highlight the importance of wild animals and remote regions as sources of novel viruses that substantially broaden the current knowledge of the global diversity of viruses.

Integrating variable retention systems into strategic forest management to deal with conservation biodiversity objectives

For the past few decades, the integration of biodiversity conservation into forest management has constituted an important challenge, since the new forest management models should make conservation objectives compatible with production issues. In many countries, timber production is no longer the main ecosystem service provided, thus other aspects such as biodiversity conservation are taken into account. One of the strategies developed to do so is to define, at the stand level, areas where final cuttings are not allowed. These areas can be found dispersed or aggregated (comprised of multiple stands) throughout the forest, helping to maintain a percentage of mature forest that fulfils conservation goals. In this study, we have developed a strategic forest planning model that allows us to integrate several retention systems compared to the business-as-usual treatment traditionally used. Production, technical and environmental criteria have been considered in order to analyse the degree of conflict between them by designing a pay-off matrix. Using multicriteria techniques conflicting objectives were assessed, and decision makers’ interactions have been introduced. These interactions range from criteria selection to the allocation of preferential weights to each criterion until the best solution among a set of possible alternatives is identified. The presented analytical procedure is based on the extended goal programming method applied in an exemplary forest in central Spain. Our results show that the proposed methodology allows deriving solutions that are acceptable for decision makers while estimating physical and economic opportunity costs of conservation measures in timber volume and Euros respectively.

Analysis of spatial correlation in predictive models of forest variables that use LiDAR auxiliary information

Accounting for spatial correlation of LiDAR model errors can improve the precision of model-based estimators. To estimate spatial correlation, sample designs that provide close observations are needed, but their implementation might be prohibitively expensive. To quantify the gains obtained by accounting for the spatial correlation of model errors, we examined (i) the spatial correlation patterns of residuals from LiDAR linear models developed to predict volume, total and stem biomass per hectare, quadratic mean diameter (QMD), basal area, mean and dominant height, and stand density and (ii) the impact of field plot size on the spatial correlation patterns in a standwise managed Mediterranean forest in central Spain. For all variables, the correlation range of model residuals consistently increased with plot radius and was always below 60 m except for stand density, where it reached 85 m. Except for QMD, correlation ranges of model residuals were between 1.06 and 8.16 times shorter than those observed for the raw variables. Based on the relatively short correlation ranges observed when the LiDAR metrics were used as predictors, the assumption of independent errors in many forest management inventories seems to be reasonable and appropriate in practice.

Selecting the best forest management alternative by aggregating ecosystem services indicators over time: A case study in central Spain

Sustainable forest management has been approached on many occasions by defining and subsequently measuring a set of initially accepted indicators. This methodology permits the aggregation of multiple goods and services with heterogeneous characteristics into forest management. However, the calculation of these indicators has usually been static. When we find ourselves in situations in which there is a need to make long-term evaluations of the effects of possible scenarios affecting forest management, a procedure has to be set up to define and aggregate the different indicators over time, as well as to integrate the preferences of the stakeholders involved in management.This study shows a goal programming-based methodology, which permits to select the best management alternative in 6 climate change scenarios when different indicators are aggregated over 100 years in a mountain forest in Central Spain. The results revealed the predominance of one management alternative (no management) when the preferences of the stakeholders were aggregated. However, when the preferential weights corresponding to some stakeholders were included separately, the solution may notably vary, especially in the case of forest owners. It was concluded that the methodology proposed allows a dynamic aggregation of diverse sustainable forest management in addition to presenting a great flexibility at the moment of selecting various solutions proposed by the goal programming model, and the preferences of the different stakeholders.

Ecosystem service provision, management systems and climate change in Valsaín forest, central Spain

This study addresses the impact of climate change and management approach on the provision of four ecosystem services (ES) (timber production, protection against gravitational hazards, carbon sequestration and biodiversity) in Valsain forest in central Spain. The hybrid forest patch model PICUS v1.6 was used to simulate the development of 24 representative stand types over 100 years (2010–2110) in a full factorial simulation experiment combining three management regimes [“business as usual” management (BAU) and two alternatives to BAU (AM1 and AM2)], a no-management scenario (NOM) and six climate scenarios (historic climate represented by the period 1961–1990 and five transient climate change scenarios). Simulations indicated relatively small differences as regards the impact of the different management alternatives (BAU, AM1 and AM2) on the provision of ES as well as a clear improvement in biodiversity, protection and carbon storage under the no-management regime (NOM). Although timber production indicators were the most sensitive to climate change scenarios, biodiversity-related indicators responded fastest to the management regimes applied. Indicators of protection against rockfall and landslides were affected by both management and climate change. The results indicate substantial vulnerability of ES provisioning under the more extreme climate change scenarios at low elevations (1250 m). At higher elevations, the productivity of Scots pine stands may show a moderate decrease or increase, depending on the climate change scenario.

Potential Germination Success of Exotic and Native Trees Coexisting in Central Spain Riparian Forests

We compared potential germination success (i.e., percentage of produced seeds that germinate under optimal conditions), the percentage of empty and insect-damaged seeds, germinability (Gmax), and time to germination (Tgerm) between the exoticsAilanthus altissima,Robinia pseudoacacia,andUlmus pumilaand two coexisting native trees (Fraxinus angustifoliaandUlmus minor) in the riparian forests of Central Spain. Additionally, we tested the effect of seed age, seed bank type (canopy or soil) and population onGmaxandTgermofA. altissimaandR. pseudoacacia, which are seed-banking species. Species ranked by their potential germination success wereA. altissima>U. pumila>R. pseudoacacia>U. minor>F. angustifolia. The combination of a highGmaxand negligible seed insect-damage providedA. altissimawith a potential germination advantage over the natives, which were the least successful due to an extremely high percentage of empty seeds or a very lowGmax.R. pseudoacaciashowed high vulnerability to insect seed predation which might be compensated with the maintenance of persistent seed banks with highGmax.GmaxandTgermwere strongly affected by seed age in the seed-banking invaders, but between-seed bank variation ofGmaxandTgermdid not show a consistent pattern across species and populations.

Age class influence on the yield of edible fungi in a managed Mediterranean forest

Lack of information and difficulty in predicting wild edible sporocarp yields is blocking its integration in forest management. In the Mediterranean area, this nontimber forest product has increased its market value, consumption demand, and interest over the last decade. In this work, sampling year and stand age effects are analyzed in order to advance knowledge of edible fungi community structure, dynamics, and production. Weekly autumnal sporocarp monitoring was performed from 1997 to 2011 in a Pinus pinaster managed forest in central Spain. After applying a random stand age-stratified survey, 21 plots of 150 m(2) have been set with three per stand age class. The forest age classes have been defined as follows: 0-10 years, mixture of parent and regenerated trees, 11-20, 21-40, 41-60, 61-90, and over 90 years. A total of 153 species belonging to 56 genera were recorded, 55 of which are edible. The production of edible sporocarps was 19.8 kg ha(-1), representing 31 % of total production. Sporocarp production presents a sharp interannual variability with autumns 62 times more productive than others. The most abundant edible species in terms of fresh weight per hectare has been Lactarius deliciosus with 7.0 kg ha(-1). Edible fungi yields registered a significant decline in 10 years following regenerative cutting. The presence of parent trees significantly increases production with regard to the first class. The highest production of edible species occurs in the middle age, 41-60 years, and in the following classes, a decrease is produced. L. deliciosus production registered differences with age, manifesting in a high yield in young stands (11-20 years) and significant recovery in woodlands near to the cutting.

Growth and carbon isotopes of Mediterranean trees reveal contrasting responses to increased carbon dioxide and drought

Forest dynamics will depend upon the physiological performance of individual tree species under more stressful conditions caused by climate change. In order to compare the idiosyncratic responses of Mediterranean tree species (Quercus faginea, Pinus nigra, Juniperus thurifera) coexisting in forests of central Spain, we evaluated the temporal changes in secondary growth (basal area increment; BAI) and intrinsic water-use efficiency (iWUE) during the last four decades, determined how coexisting species are responding to increases in atmospheric CO2 concentrations (C(a)) and drought stress, and assessed the relationship among iWUE and growth during climatically contrasting years. All species increased their iWUE (ca. +15 to +21%) between the 1970s and the 2000s. This increase was positively related to C(a) for J. thurifera and to higher C(a) and drought for Q. faginea and P. nigra. During climatically favourable years the study species either increased or maintained their growth at rising iWUE, suggesting a higher CO2 uptake. However, during unfavourable climatic years Q. faginea and especially P. nigra showed sharp declines in growth at enhanced iWUE, likely caused by a reduced stomatal conductance to save water under stressful dry conditions. In contrast, J. thurifera showed enhanced growth also during unfavourable years at increased iWUE, denoting a beneficial effect of C(a) even under climatically harsh conditions. Our results reveal significant inter-specific differences in growth driven by alternative physiological responses to increasing drought stress. Thus, forest composition in the Mediterranean region might be altered due to contrasting capacities of coexisting tree species to withstand increasingly stressful conditions.

Impact of Drought on the Intra-Annual Growth of Pinus sylvestris L.

Climatic scenarios for the Mediterranean Region forecast increasing frequency and intensity of drought events. We analyzed how Pinus sylvestris modifies its cambial phenology and intra-annual growth under enhanced drought conditions. For this purpose, a rainfall exclusion experiment was applied in 2012 to trees located in the lower elevation limit of a mountain forest in Central Spain. Preliminary results show a significantly longer growing season in small trees than in big trees, regardless of the treatment. The tracheid enlargement period was longer in control trees than in trees subjected to rainfall exclusion regardless the size class. Cambial activity and gas exchange rates of Pinus sylvestris responded immediately to drier conditions, which could indicate vulnerability to drought enhancement. Stronger differences between treatments are expected for the second year of the experiment due to the cumulative effect of drought in the rainfall exclusion plots.

Estimating biomass carbon stocks for a Mediterranean forest in central Spain using LiDAR height and intensity data

Biomass fractions (total aboveground, branches and foliage) were estimated from a small footprint discrete-return LiDAR system in an unmanaged Mediterranean forest in central Spain. Several biomass estimation models based on LiDAR height, intensity or height combined with intensity data were explored. Raw intensity data were normalized to a standard range in order to remove the range dependence of the intensity signal. In general terms, intensity-based models provided more accurate predictions of the biomass fractions. Height models selected were mainly based on a percentile of the height distribution. Intensity models selected included variables that consider the percentage of the intensity accumulated at different height percentiles, which implicitly take into account the height distribution. The general models derived considering all species together were based on height combined with intensity data. These models yielded R 2 values greater than 0.58 for the different biomass fractions considered and RMSE values of 28.89, 18.28 and 1.51 Mg ha − 1 for aboveground, branch and foliage biomass, respectively. Results greatly improved for species-specific models using the main species present in each plot, with R 2 values greater than 0.85, 0.70 and 0.90 for black pine, Spanish juniper and Holm oak, respectively, and with lower RMSE for the biomass fractions. Reductions in LiDAR point density had only a small effect on the results obtained, except for those models based on a variation of the Canopy Reflection Sum, which was weighted by the mean point density. Based on the species-specific equations derived, Holm oak dominated plots showed the highest average carbon contained by aboveground biomass and branch biomass 44.66 and 31.42 Mg ha − 1 respectively, while for foliage biomass carbon, Spanish juniper showed the highest average value (3.04 Mg ha − 1 ).

Functional performance of oak seedlings naturally regenerated across microhabitats of distinct overstorey canopy closure

The extent to which seedling recruitment is limited by summer drought in Mediterranean-type ecosystems depends on the light microsite, yet the relationship between light availability and water status, functional performance, and survival of seedlings in these systems is still unclear. Over a 3-year period, we studied the pattern of survival and functional performance of seedlings of Quercus petraea (Matt.) Liebl. and Quercus pyrenaica Willd. in a montane forest in central Spain, which is the southern edge of the natural range of Q. petraea. After a mast year of the two species, 72 plots were established in six microhabitats spanning a range of overstorey canopy closure: closed, partial and open canopies dominated by either Q. petraea or Q. pyrenaica adult trees. Seedlings of each species naturally emerged beneath the conspecific-dominated canopies. The second and third years of study were extremely dry. Three years after emergence, the greatest seedling survival occurred beneath the partial canopy of Q. pyrenaica trees (8%) and the lowest (0%) beneath the closed canopies of Q. pyrenaica and Q. petraea. Survival for Q. pyrenaica increased linearly with understorey light across the range of 10–35% Global Site Factor. Plant water deficit (estimated by leaf water potential) was high across microhabitats, and increased with light availability for Q. pyrenaica. Potential for photosynthesis (estimated by the electron transport rate of photosystem II) decreased with canopy closure; and potential for light harvesting (e.g. specific leaf area (SLA) and chlorophyll concentration) increased with closure. Extreme water deficit could be the main contributor to seedling death in the more open microhabitats, whereas light level was insufficient to maintain carbon balance under the water-stressful conditions existing beneath the closed tree canopies. Seedling establishment appears to be a limiting factor for the recruitment of both oaks within this forest in a wide range of microhabitats, especially for the more drought-sensitive Q. petraea. Moderate reductions of tree canopy cover can improve seedling establishment, but extreme summer droughts can prevent the success of any silvicultural practice made.

Object-based semi-automatic approach for forest structure characterization using lidar data in heterogeneous Pinus sylvestris stands

In this paper, we present a two-stage approach for characterizing the structure of Pinus sylvestris L. stands in forests of central Spain. The first stage was to delimit forest stands using eCognition and a digital canopy height model (DCHM) derived from lidar data. The polygons were then clustered ( k-means algorithm) into forest structure types based on the DCHM data within forest stands. Hypsographs of each polygon and field data validated the separability of structure types. In the study area, 112 polygons of Pinus sylvestris were segmented and classified into five forest structure types, ranging from high dense forest canopy (850 trees ha −1 and Loreýs height of 17.4 m) to scarce tree coverage (60 tree ha −1 and Loreýs height of 9.7 m). Our results indicate that the best variables for the definition and characterization of forest structure in these forests are the median and standard deviation (S.D.), both derived from lidar data. In these forest types, lidar median height and standard deviation (S.D.) varied from 15.8 m (S.D. of 5.6 m) to 2.6 m (S.D. of 4.5 m). The present approach could have an operational application in the inventory procedure and forest management plans.

Influence of environmental conditions on germinant survival and diversity of Scots pine (Pinus sylvestris L.) in central Spain

The aim of the study was to investigate dynamics and pattern of natural regeneration and the influence of seedbed and light on germination and initial seedling survival of Scots pine (Pinus sylvestris L.) during three growing seasons. Four 5-m2 plots in a natural Scots pine forest in central Spain were randomly established at the beginning of the regeneration process. Germination and seedling survival were recorded in 100 regeneration sampling subplots (0.25 m2) per plot, while seedbed type and the relative light intensity reaching the forest floor was characterised in 1-m2 subplots. The spatial correlations between survival, light conditions and organic matter depth were analysed through cross-variograms. Germination and survival were highly variable both within and between plots (ranging from 0 to 89%) and affected by high summer temperatures (33–35°C) in 2003. The spatial pattern characterisation of survival by Ripley’s K function showed a dominant cluster distribution. Occurrence tended to be clumped when abundance was greater than 15 seedlings, whereas for lower densities, seedlings were randomly distributed. Seedlings and herbs occupied the same sites where environmental conditions were appropriate for them to live. Spatial association occurred frequently for light and organic matter depth. Results suggested that the Scots pine seedlings in our study in central Spain preferred moderate light conditions (Global Site Factor <0.40). Thus, if this forest is to be naturally regenerated with Scots pine, the shelterwood system (whereby some mother trees are left to provide shelter for at least 5 years), along with mechanical disturbance of the seedbeds, would promote seed germination, as long as a seed source is present. However, regeneration success is affected by year-to-year conditions.

The Relationship between the Energy Expenditure during Incubation and Clutch Size in the Pied Flycatcher Ficedula hypoleuca

In a population of Pied Flycatchers breeding in nestboxes in a montane pine forest in central Spain, we performed a clutch manipulation experiment by adding or removing one egg in certain nests, while keeping the original number in other nests to serve as controls. No significant effect of clutch manipulations was detected with respect to female mass/condition at the beginning of incubation and mass/condition changes. DEE (daily energy expenditure) of incubating females, measured with doubly-labelled water, was lower for reduced than for control and enlarged clutches. DEE showed a nonlinear increasing relationship with clutch size. For nine females laying clutches of 5 there was a significant positive effect of increased clutch size on DEE, the number of incubated eggs explaining 77% of the variation in DEE. For females laying 6 eggs there was no apparent trend in DEE with clutch size, suggesting that females laying large clutches do not increase DEE further when incubating enlarged clutches.

Feeding Niches of Woodland Birds in a Montane Coniferous Forest in Central Spain during Winter

A short-term study of the feeding niche differentiation of some passerine birds was conducted in a montane pine forest in central Spain during one winter, and the results were compared with similar data from northern Europe. Only six species of passerines were fairly common in the study area. The distribution of densities seemed to be more even than in northern Europe. The so called pariform guild as defined in Scandinavian studies, was found to consist of three distinct groups of species according to their foraging patterns: a group of generalized ground, shrub and branch foragers, another of specialized foliage foragers and a third of specialized trunk foragers. The last group overlaps so little with the rest of the species, that it should be excluded from the guild. Parus montanus and Certhia familiaris are not found in central Spain, while they are common in northern Europe. Instead Sitta europaea and Certhia brachydactyla were relatively common. The higher average temperatures for the winter months in central Spain when compared with northern Europe may induce a greater resource abundance, which possibly explains the broader niche of Parus cristatus and the abundance of Sitta europaea. No major effects on the foraging patterns of Parus cristatus and Parus ater by the absence of Parus montanus were observed, but the distribution of P. cristatus in the pines may be affected by the presence of Sitta europaea.