Central Spain Research Articles

Changes in submerged macrophyte diversity, coverage and biomass in a biosphere reserve site after 20 years: A plea for conservation efforts

The conservation of submerged vegetation is crucial in the functioning of aquatic ecosystems. We have assessed, by means of subaquatic quantitative sampling transects, the current status of the hydrophytic flora in 14 lakes in the Lagunas de Ruidera Natural Park, a Biosphere Reserve site in central Spain, surrounded by a semi-arid landscape. The conforming lakes have endured several anthropic pressures for decades (e.g., eutrophication, land-use changes, etc.). By comparing the current with the former status (20 years ago) of hydrophytes in the natural park, substantial negative (species richness loss, decrease in submerged meadow coverage, particularly in the upstream lakes) and positive (natural recovery of meadows after the cut-off of sudden disturbances caused by point pollution sources, improving of trophic state in some lakes, no presence of exotic hydrophytes) changes in the lakes were noticed. We have analyzed that the disappearance of all the hydrophyte (mainly charophytes) stands would represent the loss of ecosystem services. For example, up to 70 t CH4 might be released from the charophyte detritus, an internal pool of phosphorus (as high as 1400 mgP/m2) stored in the charophytes stands could be liberated. Some lakes require special measures, but overall, to preserve this lake complex, and other similar ones, we propose to study, in detail, the causes of submerged vegetation deterioration (focusing on the presence of pesticides –in water and sediments-, and other reasons) to assess the ecological risks, to protect the groundwater resources, preventing the lakes from receiving surficial point and non-point sources of pollution.

Innovation in vine growing in a context of climate change: AKIS and map of knowledge in Central Spain

Innovation in vine growing in a context of climate change: AKIS and map of knowledge in Central Spain

Evaluating Guayule (Parthenium argentatum A. Gray) Germplasm Grown in Spain: Rubber and Resin along Three Production Cycles.

Rubber and resin are potentially important products of guayule (Parthenium argentatum A. Gray) that can assure the profitability of this crop as an agricultural alternative for the semi-arid areas of central and eastern Spain. This study analyzes, for the first time, the changes in rubber and resin production across 27 guayule accessions (traditional and modern) and along three cycles under the agroclimatic conditions of Castilla-La Mancha, simulating industrial management with a biannual harvest. The rubber content (% of dry mass) increased from 4.2% in one-year-old plants to 6.6% in two-year-old plants, but decreased after harvesting. Contrastingly, the rubber yield doubled in contiguous sampling, reaching a mean of 303.6 kg ha-1, with a maximum yield of 341.2 kg ha-1 after the first harvest. Three patterns of rubber production were established based on the production periods. A similar analysis was performed for resin production, which was heterogeneous across accessions belonging to the same rubber groups. In this case, three independent groups were established to classify the resin accumulation profiles following the same criteria of production periods. Here, we demonstrate that biannual harvesting has the potential to enhance rubber accumulation in summer, although more research is needed for its adaption to current harvesting techniques in this area.

Postcranial anomalies of Eocene freshwater pleurodiran and cryptodiran turtles from the Spanish Duero Basin.

Testudines are one of the best-represented taxonomic groups among the Paleogene taxa of the Duero Basin (Castile and Leon Autonomous Community, central Spain). Among them, Neochelys (Podocnemidide) and Allaeochelys (Carettochelyidae) are most abundant, allowing the population to be assessed for osteological anomalies. The abundance of postcranial remains of both taxa allows us to identify several individuals with potential anomalies, mostly in their shells. Some of them have already been described in previous studies, but most of them are still unpublished. The objective of this study is to analyze in detail the anomalous Neochelys and Allaeochelys remains. As a result, different categories of causal agents (such as bacteria, fungi, parasites, or trauma) have been identified as potential producers of the anomalies in these freshwater turtles. Information regarding the pathogenesis and healing stages of some of these anomalies is provided.

Young male blackcaps with blood parasite coinfections cope with oxidative stress favouring anthocyanin‐rich food during migratory fattening

Parasites may alter host physiology, which may promote behavioural adaptations to counteract their effect. Adaptive feeding may help individuals to cope with infection, especially during physiologically demanding life stages. For instance, migrating birds need fuel for long‐distance flights and repair oxidative damage caused by intense aerobic exercise, and parasites may influence on how individuals balance these needs. Infected birds may face increased oxidative challenges, which could induce them to favour antioxidant defences over other needs, such as fattening. We tested whether migrating birds can adaptively choose food according to their needs, favouring dietary antioxidants to cope with oxidative stress caused by haemosporidian blood parasites during migration. During autumn migration, we mist‐netted young male Eurasian blackcaps Sylvia atricapilla stopping over in central Spain. We placed the birds in cages where they were offered fat and anthocyanin‐enriched food alternatives. We measured preference for each food offer. We tested their infections with haemosporidian parasites by PCR techniques and their parasitaemia by blood smear inspection. We also measured physiological variables that account for nutritional and oxidative status in red blood cells and plasma. We found that birds with multiple infections favoured anthocyanin‐enriched food controlling for an effect of body mass on food preference (lean blackcaps preferred anthocyanins, likely because they are urged to repair oxidative damage upon arrival on stopover with depleted energy reserves). Haemosporidian‐infected birds had a lower antioxidant capacity of plasma, although no effect of infections on oxidative damage was detected, and individuals with more oxidative damage preferred anthocyanin‐enriched food. Our results suggest that haemosporidian infections may increase individual antioxidant needs, which could affect migratory performance if the urge to find dietary antioxidants reduces the rate of fuel consumption.

Soil elemental cycles become more coupled in response to increased nitrogen deposition in a semiarid shrubland

Abstract Background and aims Increased N deposition can break the coupled associations among chemical elements in soil, many of which are essential plant nutrients. We evaluated the effects of four years of N deposition (0, 10, 20, 50 kg N ha−1 yr−1) on the temporal dynamics of the spatial co-variation (i.e., coupling) among ten chemical elements in soils from a semiarid shrubland in central Spain. Methods Soil element coupling was calculated as the mean of Spearman rank correlation coefficients of all possible pairwise interactions among elemental cycles, in absolute value. We also investigated the role of atomic properties of elements as regulators of coupling. Results While N deposition impacts on nutrient bioavailability were variable, soil elemental coupling consistently increased in response to N. Coupling responses also varied among elements and N treatments, and four out of ten elemental cycles also responded to N in a season-dependent manner. Atomic properties of elements such as mass, valence orbitals, and electronegativity contributed to explain the spatial coupling of soil elements, most likely due their role on the capacity of elements to interact with one another. Conclusions The cumulative effects of N deposition can alter the spatial associations among chemical elements in soils, while not having evident consequences on the bioavailability of single elments. These results indicate that considering how multiple elements co-vary in topsoils may provide a useful framework to better understand the simultaneous response of multiple elemental cycles to global change.

An Ecological Overview of Halophytes and Salt-Affected Soils at El Hito Saline Pond (Central Spain): Baseline Study for Future Conservation–Rehabilitation Measures

In an attempt to boost the potential ecological viability of wetlands, this study aimed to discover the relationship between soil salinity and vegetation composition in a quasi-pristine saline pond, “El Hito Lagoon”. This wetland is situated in the largest continuous natural semi-arid steppe land of western Europe (specifically in Castilla La Mancha, Central Spain). Several soil profiles and a series of surface samples (0–10 cm) extracted from a systematic network throughout the saline pond were described, sampled, and analyzed. The most significant results included the detection of elevated levels of soil salinity, with distinctive sub-areas of extreme elevated surface salinity where the pH reading peaked at 9.89 and the electrical conductivity was higher than 40 (dS/m). The very high content of total available P displayed quite an irregular scatter within the soil profile. Specifically, the range oscillated between 8.57 mg/kg and 388.1 mg/kg, several samples having values greater than 100 mg/kg. An aspect that the abundant presence of Salsola soda, a plant frequently found growing in nutrient-rich wetlands, was able to confirm.

Cantharis zapatai nom. nov., an overlooked species of Cantharis Linnaeus, 1758 from Central Spain (Coleoptera: Cantharidae)

Cantharis zapatai nom. nov. is proposed for Cantharis schrammi Pic, 1918, which is a primary homonym of Cantharis paulinoi var. schrammi Pic, 1907. The male of the species is redescribed, and the female is described here. The aedeagus and several external features are illustrated, and the species is compared with the closest relatives. Cantharis zapatai nom. nov. differs from its congeners by the characteristic spot in the vertex, yellowish pronotum and elytra, and black scutellum and appendages. The species is known from three localities of west central and central Spain (Iberian Peninsula), Guadalupe (Cáceres) (type locality), Puerto del Milagro (Toledo) and Fuencaliente (Ciudad Real). A key to the Iberian species of the genus Cantharis is provided.

Increased density of conspecifics caused niche contraction in a multispecific passerine assemblage.

Competition is a prominent mechanism driving population dynamics and structuring community assemblage, which can be investigated by linking shifts in species' ecological niche and the densities of sympatric species because the ecological release from competitive constraints is a density-dependent process. In this work we determine how a steppe passerine community segregates their ecological niches and evaluate the role of competition in inducing changes in the ecological niche of species. We built multidimensional ecological niches (with Gaussian kernel density estimators) using data on the habitat features used by 10 bird species collected from seven sites in the natural steppes of Central Spain over 2 consecutive years. We computed distance and niche similarity metrics to explore the ecological niche partitioning of the bird community. Next, we ran multivariate linear regression models to evaluate the effects of conspecific and heterospecific density (as proxies of intraspecific and interspecific competition, respectively) on niche breadth and/or position of the three most abundant species. We found low niche overlap in the community assemblage but varying levels of niche similarity among pairs of species, which could increase the likelihood of current competition operating in the community. However, we found no effect of heterospecific density on niche breadth or position, although conspecific density was negatively related to niche breadth. Contrary to predictions of competition theory, increased density of conspecifics caused niche contraction. Our results from a multispecies system contribute to advanced knowledge of the biotic mechanisms structuring wildlife communities within the framework of ecological niche theory.

Influence of the spatial resolution of Digital Elevation Models on water-balance estimations in temporary shallow lakes

Many shallow lakes are strongly degraded and their hydroecological functioning has been altered. At the same time, their rate of disappearance is remarkably high compared to other ecosystem types. Moreover, due to their relatively small size and shallow depth these lakes are highly sensitive to meteorological variability, making them highly vulnerable to climate change. The accurate estimation of their water balance is key to identifying proper management strategies. To carefully model the water balance, it is necessary to use a Digital Elevation Model (DEM) of a high-enough spatial resolution to understand the bathymetric relationships of the basin; however, it is not always possible to generate DEMs with field data. Even when DEMs are available, it is still unclear what spatial resolution is adequate to obtain an accurate water balance in shallow lakes. The aim of this work was to analyze the influence that bathymetries from different DEMs may have on shallow lake-water-balance estimations, using Lake Alcahozo (central Spain) as a case study. To do this, hydrological balances were developed with Lidar-derived DEMs with different spatial resolutions, and these balances were compared with one developed from bathymetric field data. The hydrological models obtained were calibrated with limnimetric measurements and validated with estimates of flooded areas calculated via remote-sensing imagery. The main results showed that, to a certain extent, the different resolutions of bathymetries do not have a strong influence on the result of water-balance estimations: DEMs up to a spatial resolution of 50 m (a pixel size representing 0.3 % of the basin area) have shown similar goodness-of-fit in the modeling of the hydrological balances in our case study. Therefore, depending on the objective of the study, Lidar data with different spatial resolutions can be used, up to a minimal resolution that should be determined on a case-by-case basis.

A bothremydid turtle (Pleurodira) from the middle Cenomanian of Vale de Figueira (Belas, Portugal).

An unpublished turtle shell from the middle Cenomanian of Vale de Figueira, near Belas (Lisbon District, Portugal), is recognized by us as collected in 1880 under the direction of Carlos Ribeiro. No turtle remains from that region had so far been figured, described or discussed from a systematic point of view. The specimen corresponds to a partial but articulated shell. It is attributed to Pleurodira and, more specifically, to Bothremydidae. Only one pre-Campanian turtle specimen was previously identified at the infrafamilial level in the Cretaceous record of Portugal. It was a partial shell from the middle Cenomanian of Nazaré (Leiria District) attributed to the bothremydid Algorachelus peregrina, a species defined in a Spanish synchronous locality (Algora, in Central Spain). Several anatomical regions in the specimen from Vale de Figueira were not preserved in the partial carapace from Nazaré, and differences in the morphology of some elements are recognized between both shells. However, the individual studied here is also ascribed to Algorachelus peregrina, these differences being justified by intraspecific variability. Therefore, the specimen represents the second evidence on the species in Portugal, being the only one recognized for the Lisbon District.

Progressive pollen calendar to detect long-term changes in the biological air quality of cities in the Madrid Region, Spain

Rhinoconjunctivitis and allergic asthma are among the most frequent diseases in the world, and pollen is their main cause. The incidence of respiratory allergic diseases is expected to grow in the coming years as a consequence of ambient pollution, changes in land use and land cover in cities, and climate change. In this context of global change, the environmental information provided by monitoring and warning networks must be as updated as possible in order to be useful to the end users in the cities. The Madrid Autonomous Region (central Spain) has suffered a noticeable change in its land-use configuration in recent decades and a significant upward temperature trend throughout the entire area. We found that the aerobiological stations in the Madrid Region Palynological Network, covering the most populated cities of this region in central Spain, registered a marked shift towards a greater airborne pollen load of the most abundant tree pollen taxa (Cupressaceae, Platanus and Quercus, but also Pinaceae, Olea and others). These temporal changes are very evident in the pollen calendar for two periods, 1994–2004 (past) and 2012–2022 (present), pointing to changes in the phenology and intensity of the airborne pollen dynamic in cities in the Madrid Region. Based on these findings, we present a technical proposal to the Madrid Region Palynological Network to generate pollen calendars for each city using the reference period of the last ten years, and to update this information every three years. Finally, we propose the latest pollen calendar for all the aerobiological stations in the Madrid Region Palynological Network for the last ten years (2013–2022), which is considered the reference aerobiological information at present for one of the most populated metropolitan areas in Europe.

Changes to butterfly phenology versus elevation range after four decades of warming in the mountains of central Spain

AbstractShifts over time (phenology) and space (latitude and elevation range) represent common ecological responses to climate change. However, the factors determining how changes in phenology and distribution interact, and the consequences for conservation, remain uncertain. Here, we assess how phenology responded to temperature over four decades of warming across the elevation ranges of 18 univoltine butterfly species in four mountain regions of Spain. Using count data from intermittent surveys in 166 sites between 1985 and 2022, we tested for (1) effects of monthly temperature and elevation on mean annual flight date; (2) changes to flight dates between 1985–2005 and 2017–2022; and (3) whether shifts in flight date were related to shifts in the average elevation occupied. Mean flight dates were later in years with cooler springs, and at higher sites, with a mean delay of nearly twenty days per km elevation increase. As conditions warmed over time, average flight date advanced for two thirds of species, especially those whose average elevation was stable over time. Species with stable flight dates showed greater indication of upward range shifts, although only one species showed a significant shift in average elevation. Implications for insect conservation: We show that spring temperatures influence mountain butterfly phenology, and that shifts in phenology and elevation range could compensate for each other in determining population exposure and responses to climate change. Monitoring these changes over time, including by employing evidence from historical surveys and scientific collections, can help to understand constraints on species adaptive capacity to climate change.

Age and sex differences in pharmaceutical contamination in a keystone scavenger

Pharmaceutical contaminants have a recognized negative impact on wildlife health. However, there are still many knowledge gaps on the factors influencing exposure and metabolic processing of compound mixtures as a function of season and individual characteristics such as age and sex. We evaluated age and sex differences in a set of seventeen compounds, including eleven antibiotics, five NSAIDs and caffeine, evaluated by HPLC-MS-TOF analysis in griffon vultures (Gyps fulvus) from central Spain. Pharmaceutical cocktails (up to 10 compounds simultaneously) were found in all individuals. Lincomycin was detected in all individuals, and fluoroquinolones were found at high frequencies, while NSAIDs were at low frequencies and concentrations, including flumixin meglumine, which can be lethal to vultures. A higher total number of compounds and sum of concentrations, as well as prevalence and concentration of several of the pharmaceuticals tested was found in females than in males for both nestlings and adults. This is the first study to present evidence of sex differences in the pharmacokinetics of dietary drug contaminants in a vulture species. Chronic exposure to “medications” in entire populations can potentially have sub-lethal health effects that affect fitness differently according to age and sex, with demographic implications for population viability. Specifically, if females have higher mortality after fledging due to high pharmaceutical contamination, this should be considered when modelling the population dynamic of this species for conservation purposes.

Avian responses to an extreme weather event: The case of the ‘Filomena’ snowstorm in Madrid (central Spain)

Cold spells and severe weather may have detrimental effects in wild birds, but owing to the stochastic nature of these events, it is not always possible to measure their impacts. In January 2021, a strong snowstorm known as ‘Filomena’ affected Spain, mainly the region of Madrid (Central Spain), which was fully covered with snow and suffered freezing temperatures for a fortnight. Using bird surveys conducted in the winter-spring of 2020 and 2021 (before and after Filomena) at same locations, we addressed the possible impact of the cold spell in three widespread gamebirds: Wood Pigeon (Columba palumbus), Eurasian Magpie (Pica pica) and Red-legged Partridge (Alectoris rufa). No significant abundance differences were found between years for none of the species and hunting pressure was only significantly reduced for Partridges, hence this species may have been negatively affected by Filomena. Results suggest that in response to Filomena, Pigeons conducted partial migration in search of better conditions, while Magpies aggregated in certain areas of Madrid and Partridges endured the harsh conditions within their home ranges. Our results highlight the importance to alleviate negative impacts of extreme weather events in wild birds through management actions, especially for sedentary species.

Sediment Response after Wildfires in Mountain Streams and Their Effects on Cultural Heritage: The Case of the 2021 Navalacruz Wildfire (Avila, Spain)

The 2021 Navalacruz wildfire occurred in a mountainous area in the Sistema Central (Spain). Despite having an average low severity index (dNBR), the loss of vegetation cover associated with the fire was responsible for a high rate of sedimentation in the rivers and streams. Additionally, the burned area affected up to 60 cultural heritage sites, including archaeological and ethnological sites, and damage ranged from burnt pieces of wood to the burial of archaeological sites. In the present work, we document and analyze the post-fire evolution in several rivers and streams. This is based on a field survey of infiltration rates, hydrodynamic modeling, and the study of channel morphological changes. Our analysis revealed how the first post-fire rains caused the mobilization and transport of ashes. This created hydrophobicity in the soils, resulting in large amounts of materials being transported to rivers and streams by subsequent medium- and low-magnitude storms. A hydrological and hydraulic model of the study catchments under pre- and post-fire conditions suggests that these trends are a consequence of a post-fire increase in flow rates for similar rainfall scenarios. In this respect, our estimates point at a significant increase in sediment transport capacities associated with this post-fire increase in flow rates. The combination of locally steep slopes with high-severity fire patches, and a considerable regolith (derived from pre-fire weathering), resulted in a series of cascading responses, such as an exacerbated supply of sand to the drainage network and the triggering of debris flows, followed by erosion and entrenchment.

Height increment patterns in Pinus pinaster seedlings emerging in naturally regenerated gaps

Abstract The group selection cutting system provides a promising technique for transforming monospecific even-aged stands into uneven-aged, mixed stands. However, this system has scarcely been used to regenerate Mediterranean shade-intolerant species. In this study, we analyze the height increment patterns of Pinus pinaster seedlings emerging in naturally regenerated gaps. P. pinaster is a shade-intolerant pine species distributed throughout the Mediterranean basin. An experimental trial was established in a 50-year-old P. pinaster (maritime pine) plantation located in the mountains of central Spain. Gaps of two different sizes (diameter equal to 1.5 and 2.5 times the dominant height of the stand, 26 and 44 m, respectively) were opened during winter 2017–18. A total of 531 subplots with a 1-m radius were installed in spring 2018, distributed within the gaps as well as in control plots adjacent to the gaps. Seedlings were tagged individually and variables including height, along with other ecological variables, were collected twice a year (in spring and autumn), providing six time intervals for the development of our models. We applied seemingly unrelated regression to analyze the height growth in this polycyclic species, allowing us to model spring and autumn height increments at the same time. Our results showed that seedling height growth depended on the silvicultural treatment, meteorological conditions during the spring growth season, inter-specific scrub competition, position within the gap, and seedling characteristics, such as the ontogenetic development or the size of the seedling itself. This work, along with germination and survival analysis, aims to provide a holistic perspective on the suitability of the group selection cutting system to regenerate maritime pine stands, taking into account current and future climate change scenarios.

Valorization of Salicornia patula Duval-Jouve Young Shoots in Healthy and Sustainable Diets.

The revalorization of natural resources in food production is increasing, and the effect of climate change is negatively affecting the production of conventional crops. In recent years, edible halophytes have received more attention due to their ability to tolerate a wide range of salinities. Thus, the use of halophytes that require less water and are strongly adapted to high-salinity soil and coastal areas can provide sustainable agriculture in certain areas. In addition, there is growing interest in the study of the possibilities that these species offer as foods due to their excellent nutritional profile and antioxidant properties. For that reason, the exploitation of plants adapted to these areas is nowadays even more important than in the past to guarantee food security in arid or semiarid salinized territories. The available data about the nutrients and bioactive compounds composition of many non-cultivated edible vegetables traditionally used in the Mediterranean area, such as Salicornia edible young shoots, are still scarce. With the aim of improving the knowledge on their nutritional value, the present study provides new data about the content of some compounds with biological activity, such as fiber and organic acids, in eight samples of young shoots of S. patula Duval-Jouve gathered in great mainland and coastal salt marshes in Southwest and Central Spain. Results showed that this vegetable can be considered a healthy food and a very good source of dietary fiber (4.81-6.30 g/100 g fw total fiber). Its organic acid profile showed oxalic, malic, citric and succinic acids. Oxalic acid was the major one, with mean values of 0.151-1.691 g/100 g fw. From the results obtained in this study, S. patula shoots could be recommended as an alternative source of fiber for healthy and sustainable diets in the general adult population with no risk of renal disease.

Assessment of environmental risk areas based on airborne pollen patterns as a response to land use and land cover distribution

Allergic respiratory diseases are considered to be among the most important public health concerns, and pollen is the main cause of allergic respiratory diseases worldwide. However, the biological component of air quality is largely underestimated, and there is an important gap in the legislation in this area. The aims of this study were to characterise the occurrence and incidence of pollen exposure in relation to potential pollen sources and to delineate the main areas of aerobiological risk in the Madrid Autonomous Region based on homogeneous patterns of pollen exposure. This study uses the historical aerobiological database of the Madrid Region Palynological Network (central Spain) from ten pollen stations from 1994 to 2022, and the land-use information from the Corine Land Cover. Multiple clustering approaches were followed to group the sampling stations and subsequently all the 1 × 1km pixels for the Madrid Autonomous Region. The clustering dendrogram for land-use distribution was compared to the dendrogram for historical airborne pollen data. The two dendrograms showed a good alignment with a very high correlation (0.95) and very low entanglement (0.15), which indicates a close correspondence between the distribution of the potential pollen sources and the airborne pollen dynamics. Based on this knowledge, the Madrid Autonomous Region was divided into six aerobiological risk areas following a clear anthropogenic gradient in terms of the potential pollen sources that determine pollen exposure in the Madrid Region. Spatial regionalisation is a common practice in environmental risk assessment to improve the application of management plans and optimise the air quality monitoring networks. The risk areas proposed by scientific criteria in the Madrid Autonomous Region can be adjusted to other operational criteria following a framework equivalent to other air quality networks.

Thermodynamic and hydrological drivers of the soil and bedrock thermal regimes in central Spain

Abstract. An assessment of the soil and bedrock thermal structure of the Sierra de Guadarrama, in central Spain, is provided using subsurface and ground surface temperature data coming from four deep (20 m) monitoring profiles belonging to the Guadarrama Monitoring Network (GuMNet) and two shallow profiles (1 m) from the Spanish Meteorology Service (Agencia Estatal de Meteorología, AEMET) covering the time spans of 2015–2021 and 1989–2018, respectively. An evaluation of air and ground surface temperature coupling showed that soil insulation due to snow cover is the main source of seasonal decoupling, being especially relevant in winter at high-altitude sites. Temperature propagation in the subsurface was characterized by assuming a heat conductive regime by considering apparent thermal diffusivity values derived from the amplitude attenuation and phase shift of the annual cycle with depth. This methodology was further extended to consider the attenuation of all harmonics in the spectral domain, which allowed for analysis of thermal diffusivity from high-frequency changes in the soil near the surface at short timescales. For the deep profiles, the apparent thermal diffusivity ranges from 1 to 1.3×10-6 m2 s−1, which is consistent with values for gneiss and granite, the major bedrock components in the Sierra de Guadarrama. However, thermal diffusivity is lower and more heterogeneous in the soil layers close to the surface (0.4–0.8×10-6 m2 s−1). An increase in diffusivity with depth was observed that was generally larger in the soil–bedrock transition at 4–8 m depth. The outcomes are relevant for the understanding of soil thermodynamics in relation to other soil properties. Results with the spectral method suggest that changes in near-surface thermal diffusivity are related to changes in soil moisture content, which makes it a potential tool to gain information about soil drought and water resource availability from soil temperature data.