Modelling hydrological connectivity in burned areas. A case study from South of Spain

Overland flow connectivity depends on the spatio-temporal interactions of hydrological and geomorphic processes as well as on the human footprint on the landscape. This study deals with the modelling of hydrological connectivity in a burned area with different levels of fire severity. Namely, the objectives are to: i) characterize and ii) modelling the pre- (PreF) and post-fire (PostF) scenarios, as well as iii) evaluate the effect of the vegetation changes due to the fire and the initial post-fire management practices (construction of new skid trails and check-dams) on the magnitude and spatial pattern of connectivity. Four post-fire scenarios are simulated: immediately after the fire (PostF1), with new skids and without check-dams (PostF2), with new skids and check-dams and without vegetation recovery (PostF3), and with new skids and check-dams and incipient vegetation cover (PostF4). The study area corresponds to eleven headwater sub-catchments (total area of 329 ha) that cover the entire burned area of the mountain in the West and Southwest facing hillslopes (ca. 200 ha). This site is located in the province of Malaga, South of Spain, and all sub-catchments are disconnected between them. The fire started in 2014, 27 June and lasted two days. The landscape is mainly mountainous, with very steep slopes and marble rocks, Mediterranean climate, and a land use of shrubs and pine forests (pre-fire scenario). Settlements appear at the bottom of the slopes. After the wildfire, land management were carried out in order to remove completely the burned trees and thus new skid trails were built. Then, eleven concrete check-dams and twelve wooded check-dams were built in the main gullies. The different scenarios of linear landscape elements, vegetation cover and modifications on the topography related to the construction of new trails and check-dams were included in the simulations. The IC index of hydrological connectivity was chosen to perform this metric at a spatial resolution of 5 x 5 meters. The analysis of the different spatial patterns and temporal changes was done considering the different levels of fire severity and changes on hydrological connectivity were also analysed at the outlet of each sub-catchment.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Methodological approach for mapping ecosystem services in urban and suburban areas.

In Urban and suburban areas, the technology of remote sensing can offer a practical and economical means to study ecological quality of cities based on the specific functions or functional groups/biodiversity which support the supply of ecosystem services (e.g. habitats for species, maintenance of genetic diversity). This is because many ES are ecological processes or directly products by them. Other ecological processes can have detrimental effects on service supply. Thus, mapping the spatial distribution and the degree of ecosystem functionality can provide useful information of the service provided by them to the urban population. Within the framework of the Urbangaia project, the purpose of this study is to bridge present a methodology of ecosystem service related research in ecology and remote sensing in urban areas. Specifically, the study presents a remote sensing-based method for ES potential assessment in four European studies cases- Ghent, Coimbra, Vilnius and Leipzing-. Land cover was used as a proxy measure of ecosystem services because of its multiple linkages to carbon storage, watershed protection, and other types of services. For each land cover type, the services provided by the ecosystem are identified and given a monetary value based on previous studies and original calculations. A GeoEye-1 Satellite Sensor (0.5m spatial resolution) has been used in each study case, for its broad spatial coverage of its images. Several key areas are considered such as land cover, biodiversity, carbon, water and soil related ecosystem service. By the analysis of the different studies cases, the study also gives some global recommendation.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Does malaga city have green and blue infraestructures? analysis of their ecological connectivity, population accesibility and potential ecosystem services

Ecosystem services (ES) are defined as “benefits people obtain from ecosystems”, and classified as provisioning, regulation and maintenance, and cultural services. Nowadays, there is continuous search for incrementing wellbeing, besides a higher concern for environment. Accordingly, ES contribute positively to decrease these concerns. Green and blue infrastructures (GBI) play an important role in the regulation of natural cycles in urban and periurban areas, providing a number of ES, not always considered in planning and decision making process. GBI may be designed to reduce the ecological footprint, reduce natural hazards, and improve the quality of urban living environment (e.g air quality, water quality, noise, climate, aesthetics). GBI provide space for relaxation and restoration as well as exercise and leisure activities, promote new green services and jobs, and therefore increase the resilience of cities facing the Global Change. Many Mediterranean cities present few spaces considered as GBI. In our case study, does Málaga city have GBI providing ES to its population? Málaga is a Mediterranean city of importance in southern Europe due to its strategic location and good communications. It has a population of almost 600.000 people plus the great amount of tourist throughout the year. Thus, it would be rather important to have GBI improving urban quality life and well-being.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Assessment of the vegetation cover in a burned area 22-years ago using remote sensing techniques and GIS analysis (Sierra de las Nieves, South of Spain).

The study aim was to characterize the vegetation cover in a burned area 22-years ago considering the previous situation to wildfire in 1991 and the current one in 2013. The objectives were to: (i) compare the current and previous vegetation cover to widlfire; (ii) evaluate whether the current vegetation has recovered the previous cover to wildfire; and (iii) determine the spatial variability of vegetation recovery after 22-years since the wildfire. The study area is located in Sierra de las Nieves, South of Spain. It corresponds to an area affected by a wildfire in August 8th, 1991. The burned area was equal to 8156 ha. The burn severity was spatially very high. The main geographic features of the burned area are: mountainous topography (altitudes ranging from 250 m to 1500 m; slope gradient >25Remote sensing techniques and GIS analysis has been applied to achieve the objectives. Landsat 5 and Landsat 8 images were used: July 13th, 1991 and July 1st, 2013, for the previous wildfire situation and 22-years after, respectively. The 1990 CORINE land cover was also considered to map 1991 land uses prior the wildfire. Likewise, the Andalucía Regional Government wildfire historic records were used to select the burned area and its geographical limit. 1991 and 2013 land cover map were obtained by means of object-oriented classifications. Also, NDVI and PVI1 vegetation indexes were calculated and mapped for both years. Finally, some images transformations and kernel density images were applied to determine the most recovered areas and to map the spatial concentration of bare soil and pine cover areas in 1991 and 2013, respectively. According to the results, the combination of remote sensing and GIS analysis let map the most recovered areas affected by the wildfire in 1991. The vegetation indexes indicated that the vegetation cover in 2013 was still lower than that mapped just before the 1991 widlfire in most of the burned area after 22-years. This result was also confirmed by other techniques applied. Finally, the kernel density surface let identify and locate the most recovered areas of pine cover as well as those areas that still remain totally or partially uncovered (bare soil.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Los incendios forestales y la configuración del paisaje de la montaña mediterránea. Un caso de estudio

Los incendios forestales, en íntima relación con la gestión histórica del territorio, son un agente modelador del paisaje de la montaña mediterránea desde hace varios miles de años. El resultado ha sido un paisaje a veces fragmentado en teselas, a veces ocupado por manchas de formaciones vegetales muy diferentes a las originarias, de una calidad visual intrínseca. En relación con este concepto, cabe destacar la fragilidad visual del paisaje, definida como la susceptibilidad de una paisaje al cambio cuando se desarrolla un uso sobre él. Esta propiedad del paisaje expresa el grado de deterioro del mismo ante la incidencia de determinadas actuaciones. Si consideramos un incendio forestal un tipo de actuación llevada a cabo en el territorio, este fenómeno que puede tener un gran impacto territorial supone un cambio dramático en el paisaje. Un término opuesto que permite evaluar indirectamente la fragilidad visual es la capacidad de absorción visual o capacidad del paisaje para acoger modificaciones que produzcan variaciones en su carácter visual. En este trabajo, se realiza una breve actualización de los estudios sobre los efectos de los incendios forestales en la configuración actual del paisaje de la montaña mediterránea. Asimismo, se presenta un caso de estudio sobre las consecuencias paisajísticas de un incendio forestal en un área de montaña en la provincia de Málaga; concretamente, la zona de estudio se localiza en el municipio de Cómpeta.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Impact of prescribed fire in soil properties after 5-years: experimental study.

Wildfires are a serious problem in areas with a Mediterranean climate owing to the hot summers and drought conditions providing perfect conditions for wildfire, especially when there are large amounts of fuel accumulation and continuity between forested areas. In the Mediterranean, high severity fires that spread rapidly are common and difficult to be extinguished. Thus, the identification of tools to reduce fire spread and minimize their incidence and effects is crucial. Preventive forestry is a good tool for achieving forest structures with lower amounts of fuel and a greater resistance to fire. Prescribed fire is the planned use of fire under predetermined weather, fuel and topographic parameters to achieve clearly defined objectives as controlling fire regimes by managing fuel, counteracting the disappearance of biomass-consuming land management practices and reducing the overall fire risk. Normally, prescribed fires are low intensity fires and, if managed adequately, do not cause any damage to trees, especially in Mediterranean ecosystems where trees are resilient to fire. Besides, prescribed fires usually have different impacts on soils, water resources, biodiversity, the risk-reduction of wildfires and carbon storage. Prescribed fires usually are of low/moderate severity. Because of this, the effects of prescribed fires on soils properties may vary from one site to another. The objectives of our study are to: i) determine the impact of the prescribed fire just after and ii) 5-years later with respect to natural conditions. To do this, in 2011, a prescribed fire was conducted in one experimental area of Mediterranean rangeland. After the fire, soil samples (0-5 cm of depth) were taken in burned and unburned plots in order to analyse: pH, electrical conductivity (EC), soil organic carbon, cationic exchangeable capacity (CEC), aggregate stability (AS), and hydrophobicity. The results indicated that: i) prescribed fire only had significantly effects in CEC just after the fire; 5-years after, there were no significant differences between the unburned and burned plots, but two soil properties significantly changed when burned soil samples from 2016 and 2011 were compared: EC and AS in the fraction of 0.053-0.125 mm. In general, the soil properties were not substantially modified by the prescribed fire, supporting the idea it is a very useful tool with very low impact for managing Mediterranean rangelands in order to reduce fuel accumulation and fire risk.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Available water modifications by topsoil treatments under mediterranean semiarid conditions: afforestation plan

During dry periods in the Mediterranean area, the lack of water entering the soil matrix reduces organic contribu- tions to the soil. These processes lead to reduced soil fertility and soil vegetation recovery which creates a positive feedback process that can lead to desertification. Restoration of native vegetation is the most effective way to regenerate soil health, and control runoff and sediment yield. In Mediterranean areas, after a forestry proposal, it is highly common to register a significant number of losses for the saplings that have been introduced due to the lack of rainfall. When no vegetation is established, organic amendments can be used to rapidly protect the soil surface against the erosive forces of rain and runoff. In this study we investigated the hydrological effects of five soil treatments in relation to the temporal vari- ability of the available water for plants. Five amendments were applied in an experimental set of plots: straw mulching; mulch with chipped branches of Aleppo Pine (Pinus halepensis L.); TerraCotten hydroabsobent polymers; sewage sludge; sheep manure and control. Plots were afforested following the same spatial pattern, and amendments were mixed with the soil at the rate 10 Mg ha-1. In control plots, during June, July, August and September, soils were registered below the wilting point, and therefore, in the area of water unusable by plants. These months were coinciding with the summer mediter- ranean drought. This fact justifies the high mortality found on plants after the seeding plan. Similarly, soils have never exceeded the field capacity value measured for control plots. Conversely, in the straw and pinus mulch, soils were above the wilting point during a longer time than in control plots. Thus, the soil moisture only has stayed below the 4.2 pF suction in July, July and August. Regarding the amount of water available was also higher, especially in the months of December, January and February. However, the field capacity value measured has not showed any differences regarding the control. For these treatments, the survival sapling rates measured were the highest. Sludge, manure and polymers showed a moisture retention capacity slightly more limited than straw and pinus mulch. Likewise, it has been found that the area of usable water by plants was also lower, especially during the months of January and February. This situation is especially sharpened in plots amended with manure. In this treatment, the upper part of the soil profile was below the wilting point for six months a year (from April to August). For this treatment, the survival sapling rates measured were the lowest. In conclusion, from a land management standpoint, the pinus and straw mulch treatments have been shown as effective methods reducing water stress for plants. In this research, mulching has been proved as a significant method to reduce the mortality sapling rates during the mediterranean summer drought.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Hydrological and sediment connectivity in three grazed Mediterranean hillslopes.

Masselink et al. (2016) addressed the concept of connectivity addresses the spatial and temporal variability in runoff, sediment transport and associated substances such as pollutants and how these move through the catchment. Sediment connectivity explains which sediment sources contribute and where (semi-) permanent sinks and pathways of sediment are (Bracken & Croke, 2007). The Mediterranean eco-geomorphological landscape is highly dependent on the climatic conditions. Its elements form the spatial patterns of landscapes, which control the structural connectivity. The existence of rainfall gradients in the Mediterranean region has been well-documented (Lavee et al., 1998) along which those elements are modified by the spatio-temporal variability of rainfalls. The characteristics of those elements are modified from the rainiest to the driest regions following a positive feedback process leading to soil erosion and degradation. As the climate becomes less rainy, the patchy vegetation pattern becomes frequent and bare soil areas can be easily connected whether the magnitude and intensity of rainfall exceed a certain threshold (Cammeraat, 2004). The interaction between topography and processes occurring within catchments is key to understanding dynamics of hydrological connectivity (Wainwright et al, 2011). Our study evaluated the hydrological and sediment connectivity between sections (top, middle and bottomchannel) from three grazed hillslopes located under contrasted Mediterranean climatic conditions. Rain-gauge stations and opened-plots were installed in order to register overland flow and sediment concentration from Feb-2008 to Jan-2010. The results indicated that: i) major volumes of overland flow and sediment transport occurred more frequently in humid and semiarid sites; ii) the more frequent hydrological connectivity was observed between the middle and bottom-channel sections, though the major values of overland flow and sediment concentration were registered in the upper sections; iii) it was found very frequent those rainfall events in which all sections contributed with overland flow and sediment to the channel; iv) the factors controlling hydrological and sediment connectivity varied from one site to another depending on the rainfall regime and vegetation cover, though the soil surface conditions were found a key factor in all of them. In summary, the grazing activity contribute to distance the hydrological and sediment connectivity processes from three hillslopes located under contrasted Mediterranean climatic conditions from the response expected for the three of them. References Bracken LJ, Croke J. 2007. The concept of hydrological connectivity and its contribution to understanding runoff-dominated geomorphic systems. Hydrological Processes 21: 1749–1763. Cammeraat ELH. 2004. Scale dependent thresholds in hydrological and erosion response of a semi-arid catchment in Southeast Spain. Agriculture, Ecosystems and Environment 104: 317–332. Lavee H, Imeson AC, Sarah P. 1998. The impact of climate change on geomorphology and desertification along a Mediterranean-arid transect. Land Degrad. Develop. 9: 407-422. Masselink RJH, Keesstra SD, Temme AJAM, Seeger M, Giménez R, Casalí J. 2016. Modelling discharge and sediment yield at catchment scale using connectivity components. Land Degrad. Develop. 27: 933-945. Wainwright J, Turnbull L, Ibrahim TG, Lexartza-Artza I, Thornton SF, Brazier R. 2011. Linking environmental regimes, space and time: interpretations of structural and functional connectivity. Geomorphology 126: 387–404.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Analysis of heavy rainfall in two contrasted Mediterranean watersheds from 1993 to 2017

"Despite the proximity of the watersheds there are strong" "environmental contrasts between both." "• The current rainfall dynamics follows a trend towards concentration in fewer days." "• A rainfall cataloged as torrential by the AEMET (≥ 100 / 24h, ≥60 mmh-1) is not necessary to activate erosion and degradation processes, especially when the system conditions are vulnerable. There are downpours hidden in the hourly precipitation data that get at very high intensities." "• It is considered the need to analyze exhaustively the characteristics of a given system, in order to establish what capacity of response has a specific area in an event of extreme precipitation.

The geomorphological rainfall in the Mediterranean landscape modeling

The kinetic energy derived from the heavy rainfall constitutes one of the main factors of the geomorphological processes in Mediterranean environments, as well as in the landscape and the ecosystem modeling, resulting from its extraordinary spatial and temporal variability. When the rainfall is analyzed, particularly in Mediterranean climate and in the context of Climate Change, it is not only necessary to consider the total rainfall collected annually, but also it is essential to take into account other variables as intensity, duration, and frequency. A series of extreme rainfall databases have been analyzed for the last 25 years (1993-2017), with daily, horary and 10-minutes registers. These have been obtained from different weather stations belonging to the Agencia Estatal de Meteorología –AEMET- and the S.A.I.H. Hydrosur Network, spatially distributed in two regions of the province of Malaga. (Guadalhorce and Axarquía). The results show the limited frequency of the events considered as torrential rainfall according to the Agencia Estatal de Meteorología criteria ( 100mm/24h; 60mm/60’) and a high occurrence of shorts heavy downpours ( 10mm/10’), especially in recent years. These downpours have been classified as “geomorphological rainfall”, short events capable of activating hydro-soil processes, owing to its high intensity and the vulnerable conditions of the eco-geomorphological system in the study areas