Cabo De Gata-Nijar Research Articles

Paecilomyces variotii as A Plant-Growth Promoter in Horticulture

In the present study, P. variotii, an endophytic fungus isolated from plant roots from the Cabo de Gata Natural Park (Parque Nacional Cabo de Gata—Spain), was tested to determine the effect on the growth promotion of tomato and pepper seeds and seedlings. For these purposes, germination trials in a laboratory and two experiments in a commercial nursery and greenhouse conditions were performed. The P. variotii isolate has shown a high ability to produce siderophores and IAA, but low ability to solubilize P. High values for germination percentage, seedling vigor, root and shoot length were obtained by P. variotii on tomato and pepper against control. P. variotii applications resulted in improved most of the growth parameters evaluated, for both horticultural crops, with the best results in the development of pepper seedlings. The application of a higher dose of P. variotii improved most of the morphological parameters and the Dickson quality index (DQI) value in tomato in seedlings and plants. The establishment of the endophytic fungus at the root enabled its biostimulant effects to persist after transplantation without any additional application. Few studies have analyzed this species as a biostimulant. The positive results from the tests showed its high potential. The application of this isolate can be of enormous benefit to horticultural crops for its high reproductive and establishment capacity.

Geotouristic aspects of the Geopark Cabo de Gata-Níjar (Andalusia, Spain)

The Cabo de Gata-Nijar Geopark is one of the most remarkable examples of the geological heritage in Spain, and it comprises the largest volcanic massif in Andalusia. It is built of andesites and dacites with such typical volcanic forms like lava flows, volcanic calderas, volcanic domes and columnar joints. The ancient beaches and reefs demonstrate the presence of climate change as well as of a subtropical sea. The tourism in this region is mainly focused on its beaches and some remains of the cultural heritage, like salt works or the Rodalquilar gold mine. This study pretends to analyze the reasons and consequences of this matter. Highlighting the good state of preservation of this area and the possibility of enjoyment of its beauty, more attention should be paid to the popularization of the local geological aspects, which would significantly increase the awareness and interest among the tourists.

Management Implications for the Most Attractive Scenic Sites along the Andalusia Coast (SW Spain)

A coastal scenery assessment was carried out at 50 sites along the 910 km long Andalusia coast (SW Spain) using a checklist of 26 natural and human parameters, parameter weighting matrices, and fuzzy logic. A scenic classification was utilised that can rate sites as Class I (natural areas of great scenic beauty) to Class V (urbanised areas of poor scenic interest), but, for this study, only natural sites of great scenic value were investigated; 41 sites were included in Class I, 9 in Class II and, apart from four, all of the sites were under some feature of protection—managed by the Andalusia Environmental Agency (RENPA, in Spanish). Sites belong to the Natural Park Cabo de Gata-Nijar (24% of sites), the Natural Park of Gibraltar Strait (18%), the Natural Place Acantilado de Maro-Cerro Gordo (12%), and the Natural and National parks of Doñana (8%). Results obtained by means of scenic evaluation constitute a sound scientific basis for any envisaged management plan for investigated coastal areas preservation/conservation and responsible future developments, especially for natural protected areas, which represent the most attractive coastal tourist destinations. With respect to natural parameters, excellent scenic values appeared to be linked to the geological setting and the presence of mountainous landscapes related to the Betic Chain. Human parameters usually show good scores because null or extremely reduced human impacts are recorded, but, at places, conflicts arose between conservation and recreational activities because visitors are often interested in beach activities more so than ecotourism. Low scores of human parameters were often related to litter presence or the unsuitable emplacement of utilities, such as informative panels, litter bins, etc.

Representación Simbólica y Protección del Paisaje Marino en el Parque Natural de Cabo de Gata-Níjar (Almería- España)

En este artículo se realiza un estudio de caso centrado en el Parque Natural de Cabo de Gata-Níjar (Almería- España) sobre la correspondencia o desajuste entre las actuales representaciones virtuales de su paisaje marino y la realidad sociocultural de este espacio natural protegido. Para ello se analizará la reconstrucción simbólica del Parque Natural de Cabo de Gata Níjar, en algunos sectores de la esfera pública española. La reflexión se centra en la visibilización de las plurales representaciones simbólicas virtuales de un espacio. Tras el análisis de los resultados, se detecta en las representaciones emic virtuales una resignificación del Parque caracterizada por una espectacularización onírica de su paisaje marino. Una exaltación onírica en las representaciones emic virtuales, que prácticamente invisibilizan los problemas reales que atentan contra las costas y reserva marina de esta zona. Por el contrario, la representación mediática refleja con mayor correspondencia la realidad dialéctica del Paisaje.

Photoprotective responses in a brown macroalgae Cystoseira tamariscifolia to increases in CO2 and temperature

Global warming and ocean acidification are increasingly affecting coastal ecosystems, with impacts that vary regionally depending upon local biogeography. Ocean acidification drives shifts in seaweed community dominance that depend on interactions with other factors such as light and nutrients. In this study, we investigated the photophysiological responses in the brown macroalgae species Cystoseira tamariscifolia (Hudson) Papenfuss with important structural role in the coastal Mediterranean communities. These algae were collected in the Cabo de Gata-Nijar Natural Park in ultraoligotrophic waters (algae exposed under high irradiance and less nutrient conditions) vs. those collected in the La Araña beach in oligotrophic waters (algae exposed at middle nutrient and irradiance conditions) in the Mediterranean Sea. They were incubated in mesocosms, under two levels of CO2; ambient (400-500 ppm) and high CO2 (1200-1300 ppm), combined with two temperatures (ambient temperature; 20 °C and ambient temperature + 4 °C; 24 °C) and the same nutrient conditions of the waters of the origin of macroalgae. Thalli from two sites on the Spanish Mediterranean coast were significantly affected by increases in pCO2 and temperature. The carotenoids (fucoxanthin, violaxanthin and β-carotene) contents were higher in algae from oligotrophic than that from ultraoligotrophic water, i.e., algae collected under higher nutrient conditions respect to less conditions, increase photoprotective pigments content. Thalli from both locations upregulated photosynthesis (as Fv/Fm) at increased pCO2 levels. Our study shows that ongoing ocean acidification and warming can increase photoprotection and photosynthesis in intertidal macroalgae.

Spatial analysis of the homogeneity of the land surface temperature in three Spanish test sites

Calibration and validation (cal/val) are key activities to test the data quality acquired from satellite-based instruments, as well as to report the accuracy of derived products such as the land surface temperature (LST). Calibration of thermal infrared (TIR) data and validation of LST products at low spatial resolution requires the identification of large and homogeneous areas, which is a difficult task. In this work, spatial and temporal homogeneity of LST was analysed over three Spanish regions: the agricultural area of Barrax, Doñana National Park, and Cabo de Gata Natural Park. For this purpose, very high spatial resolution (approximately 3 m) imagery acquired with the Airborne Hyperspectral Scanner (AHS) in the framework of different field campaigns and high–medium spatial resolution (approximately 100 m) imagery acquired with the Landsat-8 (L8) TIR sensor (TIRS) have been used to retrieve homogeneity of high–medium and low spatial resolution sensors, respectively. Different LST retrieval algorithms were applied to AHS and TIRS to compare the LST for a given pixel against the LST of neighbour pixels through the computation of the root mean square error (RMSE). The results obtained from the analysis of LST derived from AHS data over Barrax and Doñana test sites show that part of these regions have an RMSE lower than 1 K, which is consistent with the accuracy of the LST validation (between 0.5 and 1.5 K). The analysis of LST derived from the TIRS shows that some parts of Doñana and Cabo de Gata sites have a mean RMSE of 1 K over the period of a year, with maximal homogeneity in autumn and winter (lower than 1 K) and minimal in spring and summer (around 2 K). These results are lower than the accuracy of the LST validation (approximately 2 K). The results show the usefulness of these three test sites to perform cal/val activities for both low and high spatial resolution sensors. The methodology presented in this study also allows the identification of suitable areas for future cal/val activities.

Cortés Vázquez, José Antonio (2013): Naturalezas en conflicto. Conservación ambiental y enfrentamiento social en el Parque Natural Cabo de Gata-Níjar. Valencia: Germanía-Asociación Valenciana de Antropología

This ethnographic book analyzes, starting from the latest advances in the anthropological reflection on the interaction between nature and culture, the processes triggered by the management of the Natural Park Cabo de Gata-Nijar.

Occurrence of the interstitial nemertean Ototyphlonemertes duplex (Nemertea: Hoplonemertea) in the Cabo de Gata Natural Park (Mediterranean, south-east Spain)

Occurrence of the interstitial nemertean Ototyphlonemertes duplex (Nemertea: Hoplonemertea) in the Cabo de Gata Natural Park (Mediterranean, south-east Spain)

Identity and Native Species Conservation: Similar Historical Ecologies from Idaho to Spain

Controversies around conservation management have elicited a growing interest in examining indigenous and local attitudes towards these initiatives. This paper argues that these attitudes not only relate to local and indigenous groups? concerns and rights, but also their particular interactions with the surrounding environment and the role this plays in collective self-definition. To do so, we compare two contrasting case studies on how different groups interpret and deal with the conservation of native species. In Idaho, Nez Perce historic interactions with wolves, livestock producers, and the State of Idaho government underpin members? perceptions of and efforts toward the reintroduction of Canis lupus. In Spain, local farmers struggle and contest the conservation measures introduced in the Cabo de Gata-Nijar Natural Park, revealing the manifold implications of their notion of ?being local?.

Diversity of arbuscular mycorrhizal fungi in the rhizosphere of Asteriscus maritimus (L.) Less., a representative plant species in arid and saline Mediterranean ecosystems

Native arbuscular mycorrhizal fungi (AMF) from saline areas could be a critical issue for success in recovering areas affected by salinity, either in natural environments or in agricultural lands. Despite its important role, there is little information on the distribution and abundance of the different mycorrhizal associations in saline environments in European Mediterranean areas. In the present study the community of AMF is investigated in the rhizosphere of a representative plant species adapted to saline Mediterranean areas, Asteriscus maritimus. Samples of the rhizosphere of twenty plants were taken from the most arid region in Europe, Cabo de Gata Natural Park, in two different areas: a dune and a salt marsh. A total of 30 AMF species belonging to three classes, five orders, nine families and 13 genera within the phylum Glomeromycota were found from both sites. In the rhizosphere of the salt marsh spore densities were six times higher than in the dunes, although the diversity was similar in both systems. One new AMF species has been described in the dune and four species could not be unequivocally identified, suggesting possible new species.

Geology of Almería – semi-desert zone of Spain

The paper presents selected geosites in the arid Province of Almería (Andalucia, Spain). This region is famous of exceptional, climatic and environmental conditions as well as of geological features. The three geological units are distinguishable in the Almeria: strongly folded and deformed metamorphic rocks of the Iberian Massif, Alpine mountain chain of the Betic Cordilliera and intra-montane basin filled with Neogene sediments. The most interesting is the region of Cabo de Gata-Nijar Natural Park, where the Miocene volcanic domes and calderas can be seen in the field. There is also a variety of exposed, igneous and sedimentary rock, as well as the relics of gold mine in Rodalquilar.

Do vegetation patch spatial patterns disrupt the spatial organization of plant species?

The mechanisms that structure plant diversity and generate long-range correlated spatial patterns have important implications for the conservation of fragmented landscapes. The ability to disperse and persist influences a plant species’ capacity for spatial organization, which can play a critical role in structuring plant diversity in metacommunities. This study examined the spatial patterns of species diversity within a network of patches in Cabo de Gata Natural Park, southeastern Spain. The objectives were to understand how the spatial heterogeneity of species composition (beta diversity) varies in a structured landscape, and how the long-range spatial autocorrelation of plant species is affected by the spatial configuration of patches. The mechanisms underlying the spatial distribution of plants acted at two scales. Between patches, spatial variation in species distributions was greater than that expected based on spatial randomization, which indicated that movement among patches was restricted. Within patches, diffusion processes reduced spatial variability in species distributions, and the effect was more prominent in large patches. Small patch size negatively influenced the long-range spatial autocorrelation of characteristic species, whereas inter-patch distance had a stronger effect on species frequency than it had on the disruption of spatial organized patterns. The long-range spatial autocorrelation was evaluated based on the dispersal abilities of the species. Among the 106 species evaluated, 39% of the woody species, 17% of the forbs, and 12% of the grasses exhibited disrupted long-range spatial autocorrelation where patches were small. The species that are more vulnerable to the effects of fragmentation tended to be those that have restricted dispersal, such as those that have short-range dispersal (atelechoric), e.g., Phlomis purpurea, Cistus albidus, Teucrium pseudochamaepytis, Brachypodium retusum, and the ballistic species, Genista spartioides. Helianthemum almeriense is another vulnerable species that has actively restricted dispersal (antitelechory), which is common in arid regions. Wind dispersers such as Launaea lanifera were less vulnerable to the effects of fragmentation. Long-distance dispersers whose persistence depends on facilitative interactions with other individuals, e.g., allogamous species such as Thymus hyemalis, Ballota hirsuta, and Anthyllis cytisoides, exhibit disrupted long-range spatial autocorrelation when patch size is reduced.

Growth forms, dispersal strategies and taxonomic spectrum in a semi-arid shrubland in SE Spain

We have identified the dispersal strategies of major growth forms in a semi-arid Mediterranean shrubland of Cabo de Gata Natural Park (SE Spain), testing (1) whether dispersal strategies and antitelechoric mechanisms vary among growth forms and families, and (2) whether dispersal traits that identify dispersal strategies can be used to predict different ways of plant survival in response to seasonal changes in their habitat. In the survey, the data of 17 dispersal traits were collected of 140 species and analysed using cluster analysis and nonlinear principal components analysis. For shrubs and forbs, low diaspore release height, spheroidal diaspores with a low mass and small size and a low to high diaspore number were associated with restricted spatial dispersal. In contrast, medium to high release height, relatively large and heavy diaspores varying in shape and a high diaspore number were associated with developed spatial dispersal (telechory). Telechory is higher in shrubs than in forbs and grasses, where atelechory/antitelechory predominate. Dispersal was synchronized mainly with the drought period (July and August) and the beginning of the rainy season (October–December). 68% of shrubs and 61.6% of forbs were anemochores, whereas zoochory (6% of shrubs) and ballistic species (8% of shrubs and 6.9% of forbs) were less common. Ombrohydrochory was well represented among forbs (27.3%) but rare among shrubs (4%). The main antitelechoric mechanisms were: bradyspory (30.7%), myxospermy (15.7%) and trypanocarpy (29.4%, only for grasses). Species with restricted spatial dispersal and antitelechoric mechanisms are well adapted to survival in semi-arid climatic conditions, and should be taken into consideration in conservation planning.

Changes in plant functional types in response to goat and sheep grazing in two semi-arid shrublands of SE Spain

In Mediterranean plant communities, grazing induces severe floristic changes affecting the life histories of grazed and non-grazed species. Alteration of the grazing regimen causes important changes in the structure and dynamics of the plant community and ecosystem stability. To determine the susceptibility of different plant functional types to landscape management, we measured changes in Plant Functional Types (PFTs) in response to grazing by goat and sheep in an inland dwarf-palm matorral and a marine-exposed thorny-shrub matorral in Cabo de Gata Natural Park (SE Spain). We classified the major life forms into PFTs, and identified six PFT shrubs (dwarf-palms, sclerophyllous small trees, xeric thorny-shrubs, spiny legumes, glaucous dwarf-shrubs, and xeric half-shrubs), four PFT forbs (leafy stem herbs, xeric prostrate herbs, rosette herbs, and clonal spiny herbs), and two PFT grasses (steppe and short grasses). Morphological traits measured include sclerophilly, leaf presence, leaf size, shape of leaf margins, hairiness, position of dormant buds (growth form), clonality, plant coverage, canopy structure, phenological deciduousness (drought resistance), and regeneration (reproduction type, pollination type, inflorescence position, and seed size). There was a higher correlation within and between morphological growth forms, leaf and phenological traits, than within regenerative traits (only seed size was correlated with main dispersal type). We analysed the importance of these PFTs at several sites of the two communities, which were subjected to different livestock rates. In inland and marine-exposed communities, the same PFTs decreased in response to medium-high grazing: sclerophyllous small trees ( Quercus coccifera, Olea europaea var. sylvestris), glaucous dwarf-shrubs ( Phlomis and Cistus spp.) and short grasses ( Brachypodium retussum). In both communities, the decrease of these grazing-susceptible PFTs was widely associated with an increase in steppe grasses ( Stipa tenacissima, “alfa-grass”) and xeric prostrate herbs ( Fagonia cretica, Paronichia sufruticosa), the latter of which is a reliable indicator of degradation in semi-arid systems. Instead, different PFTs behave as either grazing-averse and/or grazing-tolerant in each community: Dwarf-palms ( Chamaerops humilis) and xeric thorny shrubs ( Periploca laevigata) in the marine-exposed community, and xeric half-shrubs ( Thymus hiemalys, Sideritis osteoxylla, Teucrium spp., Artemisia herba-alba) in the inland community. The latter functional group resists disturbances, such as medium-moderate grazing and drought, in semi-arid zones and is an indicator of long-term degradation.

Is the analysis of plant community structure better than common species-diversity indices for assessing the effects of livestock grazing on a Mediterranean arid ecosystem?

Grazing in arid Mediterranean ecosystems brings about changes in species diversity, but the best way to measure such changes is unclear. In this study we compared various methods in order to identify indicators that might be useful for the management and conservation of grazed arid Mediterranean ecosystems. Changes in community structure and composition were compared along a previously studied grazing gradient in Cabo de Gata-Nijar Natural Park. Plant diversity was measured by calculating diversity (Shannon information index), evenness (Pielou index) and richness (species number). Rarefaction curves were used to measure plant species richness and the results were compared with traditional richness values. Community structure was measured as the percentage of bare ground and the coverage of overall perennial grasses , Stipa tenacissima L., perennial shrubs and annual plants. Our results showed that the proportion of bare ground, the cover of perennial shrubs and the relative abundance of S. tenacissima are good indicators of grazing effects on vegetation. Overall plant community structure was more sensitive to the grazing gradient than were the diversity indices. Finally, the adequacy of standardized methods for comparing species richness (i.e. rarefaction curves) along a grazing gradient are discussed.

Effects of cessation of grazing on leaf‐level photosynthesis of Periploca laevigata

Abstract. The impact of grazing pressure on gas exchange of Periploca laevigata was studied in relation to its nutritional status. P. laevigata, a woody and highly palatable shrub, is an important forage species in the dry season in Cabo de Gata Natural Park (Almeria, SE Spain) where this study was carried out. Seasonal and diurnal courses of net photosynthesis, transpiration and stomatal conductance were measured in the field. In addition, soil and plant nutrient status were measured as potential factors influencing leaf photosynthetic levels. Early in the growing season, ungrazed P. laevigata had higher photosynthetic activity than grazed plants suggesting that the defoliated plants were still recovering from herbivore damage in the previous summer. Later in the growing season grazed P. laevigata had higher photosynthetic activity than ungrazed plants, suggesting higher metabolic activity and a possible investment in chemical defences. Concentrations of P and N in the soil were higher in the grazed area. The nutrient concentration of the leaves of P. laevigata was similar in grazed and ungrazed plants.

Effects of solar UV radiation on photosynthesis of the marine angiosperm Posidonia oceanica from southern Spain

The effects of solar irradiance on the photosynthesis of the marine angiosperm Posido- nia oceanica L. Delile were investigated by means of pulse amplitude-modulated (PAM) fluorescence in the Natural Park of Cabo de Gata-Nijar, southern Spain. The study was conducted in 2 different seasons, summer (September 1996) and winter (February 1997). Daily variation in the effective quan- tum yield (∆F/Fm') was determined in plants growing at 2.5 m and in plants transferred from 15 m to 0.5 and 2.5 m depth. Three different experimental designs were conducted: (1) Incubation of shoots under 3 different solar radiation treatments using cut-off UV filters: full solar radiation (PAR + UV-A + UV-B), solar radiation without UV-B (PAR + UV-A) and solar radiation without UV (PAR); (2) short- term exposure (30 min) to high solar irradiance (photoinhibitory phase) under all treatments followed by transfer fo the plants to low irradiance for 4 h (recovery phase); (3) Preincubation of plants for 4 d under the 3 cited treatments followed by short-term exposure (30 min) to high solar irradiance under PAR + UV-A + UV-B, PAR + UV-A and PAR. A significant decrease in ∆ F/Fm' occurred from dawn to noon (18% in September and only 6% in February), followed by total recovery during the afternoon in both seasons. The highest decrease in ∆F/Fm' occurred in shoots illuminated with PAR + UV-A radi- ation. This decrease was more pronounced in winter than in summer, and was substantially higher in plants transferred from deep (15 m) to shallow water than in plants harvested at 2.5 m. Moreover, the recovery in the afternoon was higher in plants incubated at 2.5 m than in those transferred from 15 m to shallow waters. In the second set of experiments, short exposure (30 min) of plants collected from 2.5 m confirmed that inhibition under PAR + UV-A was higher than under PAR + UV-A + UV-B. In general, full recovery after exposure to high solar irradiance (PAR + UVA + UV-B) occurred only in PAR-treated plants in September. Finally, when shoots of P. oceanica were preincubated for 4 d under PAR, PAR + UV-A or PAR + UV-A + UV-B and then submitted to full solar irradiance at the water sur- face, the greatest reduction in ∆ F/Fm' was seen in plants grown under PAR, while the lowest occurred in PAR + UV-A + UV-B pretreated plants in both seasons. Recovery was higher in PAR + UV-A + UV- B pretreated plants. UV solar irradiance also affected both maximal electron transport rate (ETR) and the initial slope of the ETR-irradiance curves. P. oceanica seems to be well acclimated to high solar irradiance, showing a high capacity for recovery. Solar UV-B might be involved in the impairment and recovery of photosynthesis, since removal of UV-B promoted higher inhibition by solar irradi- ance. The absence of UV under high PAR for several days resulted in a partial loss of the capacity for photoprotection. We conclude that UV radiation could act in the natural habitat as a trigger for the induction of photoprotective mechanisms against high solar irradiance. The ecological implication of the beneficial role of UV-B in well-acclimated marine plants to high irradiance is discussed.

An ancient Ba-Sb-Ag-Fe-Hg-bearing hydrothermal system in SE Spain

A significant characteristic of the Neogene-Quaternary volcanic province of SE Spain is its spatial and temporal relationship with gold, silver, Fe-Mn, Hg-Sb, and base-metal sulphide hydrothermal mineralization. All these deposits comprise a metallogenetic belt, which extends from the Cabo de Gata Natural Park (Almeria province) to Cartagena (Murcia province). With the exception of the famous gold-rich volcanic area of Rodalquilar, the hydrothermal systems of SE Spain are represented by the mineral deposits rich in Ba-Sb-AgFe-Hg at Las Herrerias and Valle del Azogue. The principal characteristics of these two areas are the following: 1) presence of the most important deposit of shallow marine, sulphide bearing exhalites of Spain; 2) existence of the largest fossil fumaroles in Europe related with the mineralization process, and 3) occurrence of cinnabar in relation with the Sb-rich veins. The study of these two mineralized areas has made it possible to define, for the first time, an ancient Ba-Sb-Ag-FeHg bearing hydrothermal system.

Effects of solar radiation on photosynthesis, UV-absorbing compounds and enzyme activities of the green alga Dasycladus vermicularis from southern Spain

Abstract The effect of different wavebands of solar radiation (photosynthetically active radiation (PAR), ultraviolet A (UV-A) and ultraviolet B (UV-B)) produced by use of cut-off filters on chlorophyll fluorescence of the green alga Dasycladus vermicularis was assessed in summerautumn 1996 at a shallow site in Cabo de Gata-Nijar, southern Spain. Similar experiments were carried out under outdoor conditions at Malaga during summer and autumn 1997. In plants growing under in situ natural light conditions (2.5 m depth), the yield of variable chlorophyll fluorescence (ΔF/Fm′) decreases with increasing sunlight. The full solar spectrum (PAR + UV-A + UV-B) has more accentuated, long-lasting effects on fluorescence than irradiation deprived of UV-B. In general, decreases in ΔF/Fm′ do not exceed 30% in the three treatments. Under outdoor conditions, photoinhibition measured as a decrease in optimum quantum efficiency (Fv/Fm) varies between 40 and 75% with no obvious differences between treatments; however, recovery of photosynthesis after shade exposure is faster in plants treated with PAR + UV-A. Daily changes in nitrate reductase (NR) and carbonic anhydrase (CA) activities are antagonistic during the onset of natural radiation. The concentration of UV-absorbing compounds with maximum absorption at 348 and 332 nm is higher than that reported for other green algae. These compounds increase in plants exposed to the full solar spectrum (PAR + UV-A + UV-B) and decrease under PAR alone and PAR + UV-A conditions at noon. which underlines a possible photoprotective mechanism. Overall, data show that D. vermicularis is able to tolerate high solar radiation. Two physiological strategies seem to be basically active: dynamic photoinhibition at noon and an enhanced concentration of UV-screening substances.

Merging remote-sensing images for geological-environmental mapping: application to the Cabo de Gata-Níjar Natural Park, Spain

The Cabo de Gata Nijar Natural Park in Spain presents certain unique characteristics which make it of great geological, ecological and environmental interest. As a prior step to the environmental study of the park and the impact produced by the mining activities carried out up until ten years ago, the mining and waste-tip areas were defined and a lithological discrimination carried out. For this purpose, various remote-sensing techniques were employed to create high-resolution image documents on which the geological and environmental mapping of the area would be based, with special attention being paid to the areas of former mining activity because of its implications for the local environment. The merging of remote-sensing images with different spatial/spectral resolutions has become a highly useful tool, due to their increasing availability. Such is the case of the SPOT panchromatic and Landsat Thematic Mapper multispectral images, which are two of the most commonly used images in geological and environmental studies based on remote sensing. Of the numerous techniques described for merging remote sensing image data, this paper analyses those based on Intensity-Hue-Saturation, Principal Component Analysis, Spherical Coordinates, High-Pass Filters and Colour Normalized transform, using SPOT panchromatic and Landsat TM data. The research goals were (1) to analyse and compare some of the most commonly used methods; (2) to select the most appropriate method for a detailed geological-environmental study, and (3) to apply the methodology to the Cabo de Gata-Nijar area, the site of one of the most distinctive natural parks in the country.