Papers by Susana Bautista
New Forests, Nov 12, 2021
The development of silvicultural practices that seek to promote structural heterogeneity is incre... more The development of silvicultural practices that seek to promote structural heterogeneity is increasingly demanded. This work investigates the effect of thinning spatial pattern on the response to pre-commercial thinning of dense Aleppo pine post-fire stands. On three replicated experimental sites in SE Spain, we applied the following treatments: 600 trees/ha, regular thinning pattern (600R), with residual trees evenly spaced; 600 trees/ha, aggregated thinning pattern (600A), with residual pines arranged in clumps of ∽25 trees with a local within-clump density of 2500 trees/ha; and control treatment, with no thinning applied (> 20,000 trees/ha). We assessed treatment effects on pine growth, size-growth relationships, soil water content, and understory vegetation over the first three years after thinning application. Both regular and aggregated thinning pattern similarly increased pine radial growth. In general, dbh growth rates in response to thinning were faster for smaller trees than for larger trees. The growth rate of pine height was higher for 600R and control than for 600A, indicating a positive effect on height of both low and very high pine densities. We found a near-term positive effect of aggregated pattern on water availability at the stand level, mostly resulting from enhanced soil water content in the canopy gaps. For both thinning patterns, the recovery of understory vegetation was dominated by resprouter species. This study highlights the potential of aggregated thinning patterns to enhance the complexity and heterogeneity of the pine stands without compromising pine growth, which could be of great use to managing pine forests in Mediterranean areas.
Dehydrogenase activity Microbial biomass Resprouter species Seeder species Soil basal respiration... more Dehydrogenase activity Microbial biomass Resprouter species Seeder species Soil basal respiration Water soluble carbon The strong relationships between plant and soil microbial communities suggest that post-fire vegetation may be a critical driver of the post-fire recovery of the structure and functioning of the soil microbial community. In this study, we conducted an experimental burning and evaluated the effect of the post-fire persistence traits of the vegetation (resprouter and seeder) on the medium-term (3 years after fire) post-fire response of the soil microbial activity in Mediterranean shrublands. The experiment was carried out in a Mediterranean shrubland (Eastern Spain), where four main types of microsites were selected: Bare-soil inter-patch (BS); Resprouter patch (R), Seeder patch (S), and Mixed patch (R+S). For each microsite, we analyzed soil basal respiration, water-soluble carbon, microbial biomass carbon, total organic carbon, and dehydrogenase activity at 0-5 cm soil depth. We also assessed plant cover dynamics. Our results suggest that, in general, fire impacts on soil microbial activity are not long-lasting, with most assessed soil variables being similar between burned and unburned areas three years after the fire. However, while the unburned microsites showed a trend in microbial biomass and activity from lower values in bare soils to higher values in R+S patches, these differences disappeared in the burned area, due to both a slight increase in microbial activity and biomass in bare soils, and the opposite response for soils under R+S patches. Our results highlight the role of the plant persistence trait in the microbial post-fire response of Mediterranean soils.
WIT Transactions on Ecology and the Environment, 1970
Patch-gap analysis of presence-absence data in vegetation transects using hidden Markov models, w... more Patch-gap analysis of presence-absence data in vegetation transects using hidden Markov models, with application to the characterisation of post-fire plant pattern disturbance in a semiarid pine forest.
Ecosistemas: Revista científica y técnica de ecología y medio ambiente, Dec 1, 2006
Modelos ocultos de Markov para el análisis de patrones espaciales. Los modelos ocultos de Markov ... more Modelos ocultos de Markov para el análisis de patrones espaciales. Los modelos ocultos de Markov (HMM) constituyen una herramienta de modelización altamente flexible, inicialmente utilizada en el campo del reconocimiento automático del habla, que ha encontrado en los últimos años numerosas aplicaciones en áreas científico-técnicas muy diversas, aunque su utilización en ecología es aún escasa. En esta revisión se describen los elementos esenciales de los HMM, se presentan los algoritmos básicos que facilitan su estimación y se indican algunas aplicaciones recientes, destacándose las posibilidades que pueden ofrecer para el análisis de patrones espaciales complejos, pues permiten incorporar en el proceso de modelización información a priori sobre el sistema analizado. Se muestra un ejemplo de aplicación de modelización mediante HMM de transectos de vegetación con datos de presencia-ausencia, con el objetivo de analizar las perturbaciones en la distribución espacial de la vegetación producidas por el fuego en una zona semiárida. Palabras clave: HMM, estados ocultos, patrones complejos, transectos de vegetación. Hidden Markov models for spatial pattern analysis. Hidden Markov models (HMM) constitute a flexible modelling tool, originally used in the field of automated speech recognition, that have found wide application in the last years in many scientific and technical problems, although their use in ecology is still scarce. In this review, the essential elements of HMM are described, the basic algorithms that facilitate their estimation are presented and some recent applications are pointed out, with emphasis on the possibilities that HMM offer in analysing complex spatial patterns, as they allow incorporating a priori information about the system into the modelling process. An example of application is presented where HMM are used to model vegetation transects with presence-absence data, aimed at analysing disturbances in the spatial distribution of the vegetation after a wildfire in a semiarid zone.
Land Degradation & Development, Aug 15, 2018
In Mediterranean forests and rangelands, the supply of important ecosystem services can decrease ... more In Mediterranean forests and rangelands, the supply of important ecosystem services can decrease or cease as a consequence of disturbances and climatic oscillations. Land managers can sometimes prevent or mitigate the negative effects of disturbances through appropriate land management choices. In this study, we assess the contribution of land management practices (LMPs) to the resilience of eight Mediterranean forests and rangelands to multiple disturbances. The study uses a transdisciplinary approach, involving scientists, land managers, and local administrators. Data about disturbances, ecosystem services, the role of LMPs, and the resistance of LMPs to disturbances are combined using a semi-quantitative index, and analysed to evaluate how the LMPs implemented are suited to the disturbances affecting each study site. Our results indicate that the practices analysed are particularly effective in improving resilience of ecosystems against wildfires and torrential rainfalls. However, droughts are more difficult to address, and the examined practices were heavily affected by their occurrence. Tree planting appears to be highly affected by disturbances. Practices that selectively reduce the amount of vegetation appear to be beneficial in fostering recovery of ecosystems. Our assessment also suggests that it is particularly difficult to increase resilience to droughts and fires simultaneously. Practices that aimed to mitigate the impact of land use did not always prove valuable in terms of resilience. Finally, study sites that included efforts to address disturbances in their management objectives also displayed practices making the biggest contribution to resilience.
Ecosphere
Understanding the factors that control grass–shrub interactions and coexistence is critical to th... more Understanding the factors that control grass–shrub interactions and coexistence is critical to the design of dryland management and restoration strategies. Using Stipa tenacissima tussocks as adult neighbor and Olea europaea var. sylvestris as target woody species, we performed a 5‐year‐long, large‐scale manipulative experiment to investigate the independent and combined effects of water and nutrient availability, and the modulating effects of O. europaea ontogeny on the net outcome of grass–shrub interaction. At two contrasting dryland sites, we conducted experimental plantings of Olea seedlings on two microsites: contiguous to a Stipa tussock (Stipa microsite) and on the intertussock bare‐soil areas (Open microsite), and manipulated resource availability by combining nutrient and water addition. The experiment followed a full factorial design, with all treatment combinations applied at each site. We monitored survival, height, and stem basal diameter of Olea individuals over a stu...
One of the most challenging issues in Mediterranean ecosystems to date has been to understand the... more One of the most challenging issues in Mediterranean ecosystems to date has been to understand the emergence of discontinuous changes or catastrophic shifts. In the era of the 2030 Sustainable Development Goals, which encompass ideas around Land Degradation Neutrality, advancing this understanding has become even more critical and urgent. The aim of this paper is to synthesize insights into the drivers, processes and management of catastrophic shifts to highlight ways forward for the management of Mediterranean ecosystems. We use a multidisciplinary approach that extends beyond the typical single site, single scale, single approach studies in the current literature. We link applied and theoretical ecology at multiple scales with analyses and modeling of
Springer eBooks, Sep 5, 2009
... be suited to adapt to these changes, particularly in locations where withdrawals are projecte... more ... be suited to adapt to these changes, particularly in locations where withdrawals are projected to exceed ... Water is the primary limiting factor for both natural and human dryland systems (Noy-Meir 1 ... past efforts so that we can improve our understanding of the impacts of restoration ...
Ecosystems, Mar 15, 2022
Recurrent fires can impede the spontaneous recruitment capacity of pine forests. Empirical
Frontiers in Ecology and Evolution, Oct 22, 2020
One of the most challenging issues in Mediterranean ecosystems to date has been to understand the... more One of the most challenging issues in Mediterranean ecosystems to date has been to understand the emergence of discontinuous changes or catastrophic shifts. In the era of the 2030 Sustainable Development Goals, which encompass ideas around Land Degradation Neutrality, advancing this understanding has become even more critical and urgent. The aim of this paper is to synthesize insights into the drivers, processes and management of catastrophic shifts to highlight ways forward for the management of Mediterranean ecosystems. We use a multidisciplinary approach that extends beyond the typical single site, single scale, single approach studies in the current literature. We link applied and theoretical ecology at multiple scales with analyses and modeling of
Ecosystem regeneration after wildfire in the Valencia region. The response to wildfires ofreprese... more Ecosystem regeneration after wildfire in the Valencia region. The response to wildfires ofrepresentative forest eco systems from the Valencia region is analysed in the present paper. The regenerative strategy ofthe species that dominate these eco systems is shown to be relevant, as are the physical and nutritional characteristics ofthe soils where they usually grow. The repercussions ofthe increasing fire recurrence in the loss of ecosystem regenerative capacity and complexity are discussed.
Qualitative reasoning methods have proven useful to extract qualitative information from quantita... more Qualitative reasoning methods have proven useful to extract qualitative information from quantitative data in a wide variety of applications. In this work, we analysed a 30 months record of runoff and sediment yield from an experimental station in Benidorm, SE Spain, comprising a total of 104 rainfall events. We adopted a decision-tree approach to identlfy the environmental variables, basically rainfall characteristics, whlch were the most informative to predict the production of runoff or sediment and, for these variables, to determine thresholds for chfferent levels of production. A set of 11 ramfall parameters, most of them highly correlated, were simultaneously presented to the C4.5 software tool. Using the variable AI30, which combines the information of height and intensity, 98% of the cases were correctly classified as productive or non-productive for runoff, with an estimate of 5% for the expected error. For the production of sediments, the kinetic energy of the rainfall and the storm duration were incorporated into the prechction vector, giving a 1% of rnisclassifications and an expected error of 6%. For a subset of cases, the length of the dry period and the antecedent soil moisture were also considered, but no improvement was detected. We also considered the level of production, which was automatically classified as low, medium or hgh, and obtained decision trees of lugher order with higher error rates. The usefulness and drawbacks of the methods for the problems in erosion research considered in h s work are discussed.
Science of The Total Environment, 2016
Fire-prone Mediterranean shrublands may be seriously threatened by land degradation due to progre... more Fire-prone Mediterranean shrublands may be seriously threatened by land degradation due to progressive opening of the vegetation cover driven by increasing drought and fire recurrence. However, information about the consequences of this opening process for critical ecosystem functions is scant. In this work, we studied the influence of vegetation amount, type, and spatial pattern in the variation of extracellular soil enzyme activity (acid phosphatase, β-glucosidase, and urease) in fire-prone shrublands in eastern Spain. Soil was sampled in vegetation-patch and open-interpatch microsites in 15 shrubland sites affected by large wildfires in 1991. On average, the activities of the three enzymes were 1.5 (β-glucosidase and urease) to 1.7 (acid phosphatase) times higher in soils under vegetation patches than in adjacent interpatches. In addition, phosphatase activity for both microsites significantly decreased with the fragmentation of the vegetation. This result was attributed to a lower influence of roots -the main source of acid phosphatase- in the bigger interpatches of the sites with lower patch cover, and to feedbacks between vegetation pattern, redistribution of resources, and soil quality during post-fire vegetation dynamics. Phosphatase activity was also 1.2 times higher in patches of resprouter plants than in patches of non-resprouters, probably due to the faster post-fire recovery and older age of resprouter patches in these fire-prone ecosystems. The influence on the studied enzymes of topographic and climatic factors acting at the landscape scale was insignificant. According to our results, variations in the cover, pattern, and composition of vegetation patches may have profound impacts on soil enzyme activity and associated nutrient cycling processes in fire-prone Mediterranean shrublands, particularly in those related to phosphorus.
Una vez finalizado el proceso de implantación de la totalidad del título de Grado en Biología, se... more Una vez finalizado el proceso de implantación de la totalidad del título de Grado en Biología, se plantea para este estudio una doble vertiente de trabajo: Analizar la evolución del proceso de implantación del título. Evaluar detalladamente la puesta en marcha de las asignaturas de 4º curso del Grado.
New Forests, 2021
The development of silvicultural practices that seek to promote structural heterogeneity is incre... more The development of silvicultural practices that seek to promote structural heterogeneity is increasingly demanded. This work investigates the effect of thinning spatial pattern on the response to pre-commercial thinning of dense Aleppo pine post-fire stands. On three replicated experimental sites in SE Spain, we applied the following treatments: 600 trees/ha, regular thinning pattern (600R), with residual trees evenly spaced; 600 trees/ha, aggregated thinning pattern (600A), with residual pines arranged in clumps of ∽25 trees with a local within-clump density of 2500 trees/ha; and control treatment, with no thinning applied (> 20,000 trees/ha). We assessed treatment effects on pine growth, size-growth relationships, soil water content, and understory vegetation over the first three years after thinning application. Both regular and aggregated thinning pattern similarly increased pine radial growth. In general, dbh growth rates in response to thinning were faster for smaller trees...
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Papers by Susana Bautista