Person: Jiménez Escobar, María Dolores
Universidad Complutense de Madrid
Faculty / Institute
Biodiversidad, Ecología y Evolución
Now showing 1 - 10 of 14
- PublicationErratum to: Field patterns of temporal variations in the light environment within the crowns of a Mediterranean evergreen tree (Olea europaea)(Springer-Verlag, 2016) Ventre-Lespiaucq, Agustina B.; Escribano Rocafort, Adrián Gaspar; Delgado Sáez, Juan Antonio; Jiménez Escobar, María Dolores; Rubio de Casas, Rafael; Granado Yela, Carlos; Balaguer Núñez, Luis
- PublicationEstudio de comunidades de matorral mediterráneo I(2019) López-Pintor Alcón, Antonio; Barandica Fernández, Jesús; Acosta Gallo, Belén; Casado González, Miguel Ángel; Delgado Sáez, Juan Antonio; García Avilés, Javier; de las Heras Puñal, Paloma; Herrero de Jáuregui, Cristina; Jiménez Escobar, María Dolores; López de Pablo, Carlos Tomás; Martín de Agar Valverde, Pilar; Martín Zorrilla, Juan Vicente; Morcillo Alonso, Felipe; Ortega Quero, Marta; Rovira Sanroque, José Vicente; Serrano Talavera, José ManuelConjunto de guiones de prácticas de Ecología, correspondientes al bloque temático sobre el estudio de comunidades, y material complementario (estadillo y plantilla para la matriz de datos).
- PublicationGuía Rápida de SPSS v.25 (Prácticas de Ecología)(2019-06) López-Pintor Alcón, Antonio; Barandica Fernández, Jesús; Acosta Gallo, Belén; Casado González, Miguel Ángel; Delgado Sáez, Juan Antonio; García Avilés, Javier; de las Heras Puñal, Paloma; Herrero de Jáuregui, Cristina; Jiménez Escobar, María Dolores; López de Pablo, Carlos Tomás; Martín de Agar Valverde, Pilar; Martín Zorrilla, Juan Vicente; Morcillo Alonso, Felipe; Ortega Quero, Marta; Rovira Sanroque, José Vicente; Serrano Talavera, José ManuelGuía rápida de SPSS v.25 para usar en las Prácticas de Ecología (Grado en Biología, 3er curso)
- PublicationSoil development at the roadside: a case study of a novel ecosystem(Wiley, 2011-11-23) Jiménez Escobar, María Dolores; Ruiz-Capillas, P.; Mola, Ignacio; Pérez Corona, Esther; Casado González, Miguel Ángel; Balaguer Núñez, LuisOver the last few decades, road construction has increased dramatically, and new surfaces have appeared in most landscapes. Standard roadside reclamation practices often fail, because vegetation establishment appears to be limited by microsite availability. We considered soil properties as a key factor driving vegetation establishment on roadslopes over time. We address the following questions: (i) Are soil features conditioned by type of roadslope, position thereupon or applied hydroseeding? (ii) Is there any evidence of soil development at the roadside four years after road construction? (iii) Do mutual interactions exist between soil features and vegetation cover? We designed an experimental set-up on a highway in Central Spain (Madrid). We selected 15 roadslopes (nine roadcuts and six embankments) with three hydroseeding treatments (commercial, alternative and untreated). Four years after the road construction, we considered three roadslope positions (top, middle and bottom) to take into account the geomorphological gradient.We monitored soil features and vegetation cover over 4 years after the road construction. Soil chemical differences were found between roadslope types, mainly resulted from topsoil spreading on embankments and the weathering of the newly exposed materials on roadcuts. Applied amendments do not affect soil fertility or vegetation cover. In the course of time, vegetation establishment and geomorphological gradients operate differentially on roadcuts and embankments. Accordingly, cycling back of organic compounds or geomorphological processes differs between roadslopes types. Restoration efforts should be directed to guarantee key ecological processes and support soil formation.
- PublicationSpatial and demographic structure of tara stands (Caesalpinia spinosa) in Peru: Influence of present and past forest management(Elsevier, 2016-10-01) Cordero, I.; Jiménez Escobar, María Dolores; Delgado Sáez, Juan Antonio; Villegas, L.; Balaguer Núñez, LuisTropical dry forests are highly endangered ecosystems that have been scarcely studied. Many species within these forests suffer regeneration problems due to unsustainable management regimes. In particular, a regeneration problem has been detected in a forest of tara (Caesalpinia spinosa), a neotropical tree of high ecological and economic value, in Atiquipa (Peru). The study of the spatial patterns and population structure of forests can help us understand their dynamics and evaluate the effects of management. In this article, we analyse the stand demographic structure, spatial distribution and patterns of plant interactions in tara forests. We evaluate whether the regeneration problem in Atiquipa is strictly local or a problem of general concern and investigate the most probable causes. Four tara stands were selected at different localities in Peru. Two stands (Andurco and Polán) had a reverse J-shaped diametric structure, typical of stable self-replacing forests, although Polán had a low number of young trees, indicating an incipient regeneration problem. The Lloque histogram was skewed (with a maximum in seedlings 61 cm), indicating over-exploitation in the past and present forest regeneration. Maguey had a low number of regenerates, with peaks in some intermediate diametric classes, which may indicate natural regeneration problems or some past management. Spatial distribution of tara trees did not depart from the null model (�random distribution), typical of trees dispersed by zoochory. Maguey was an exception, showing a regular pattern at short distances, possibly associated with past management (like selective cuttings and/or plantations). These results suggest that in most of the analysed stands the current forest management (i.e. excessive seed collection or grazing) limits tara forest regeneration. However, the only stand with a protected status presented a clear tendency toward population increase. Bivariate analyses revealed an aggregated pattern between seedlings and adult trees. Moreover, the plant-plant interaction study showed that seedlings were associated with woody vegetation. These positive associations highlight a facilitative effect that ameliorates stressful microclimatic characteristics and/or protects tara seedlings from herbivory. The results of this study support some recommendations for sustainable management, such as controlled stocking rate, limited seed collection and promotion of bush cover.
- PublicationSoil functionality at the roadside: Zooming in on a microarthropod community in an anthropogenic soil(Elsevier, 2013-08-26) Magro Ruiz, Sandra; Gutiérrez López, Mónica; Casado González, Miguel Ángel; Jiménez Escobar, María Dolores; Trigo Aza, María Dolores; Mola, Ignacio; Balaguer Núñez, LuisEarth movements for road construction give rise to nutrient-poor anthrosols. Early onset of soil processes in these environments has been reported on the basis of plant cover establishment. Evidences of full soil functionality, however, would reveal the emergence of a self-sustainable ecosystem on these manmade substrates. The aims of the present study involved (1) assessing soil functionality on six-year-old road embankments by means of the QBS index, based on microarthropod communities (2) elucidating soil properties responsible for the composition of soil microartrhopod communities, and (3) exploring the practical implications of soil quality for road embankment management. Road embankments were functional with QBS values comparable to those found in natural systems (>100). Soil quality in these environments depended on soil organic carbon dynamics. Among the 36 arthropod groups found, Acari and Collembola dominated the soil community. Variation in microarthropod community composition was best explained by higher abundances of Brachypilina (Oribatida, Acari) and Symphypleona (Collembola). These trends in soil community structure were intimately linked to soil organic carbon content, clay content and humidity. Given its relevance, the acknowledgment of the early functionality attained by these roadside anthrosols should lead to the revision of current protocols for roadslope monitoring and management.
- PublicationSink strength manipulation in branches of a Mediterranean woody plant suggests sink-driven allocation of biomass in fruits but not of nutrients in seeds(Springer, 2016-07-25) Catalán, Pablo; Delgado Sáez, Juan Antonio; Jiménez Escobar, María Dolores; Balaguer Núñez, LuisThe relative autonomy of branches within an individual plant may favor different resource allocation responses after reproductive losses. The assessment of these reproductive strategies at the branch level before their integration at the plant level would provide more insight into how plants deal with reproductive losses. Here, we present a field experiment to assess changes in the allocation strategies at the branch level after sink strength manipulation in a Mediterranean woody plant (Cistus ladanifer). We applied three levels of removal of developing fruits (75, 25 and 0 %) on branches of the same plants, and measured their effects on resource allocation (biomass, nitrogen and phosphorus) and seed production after controlling for the effects of branch diameter and leaf weight per branch. Our results suggest that after experimental fruit thinning, C. ladanifer branches presented a sink-driven allocation of biomass to fruits but this was not the case for the allocation of nutrients to seeds, which could be driven by competition with leaf biomass. Reductions in biomass per fruit resulted in a reduction in seed output since the average weight per seed remained constant. From these results, it could be suggested that an heterogeneous distribution of fruit losses among the branches within a crown would produce a higher impact on reproductive output than a more equitable distribution.
- PublicationField patterns of temporal variations in the light environment within the crowns of a Mediterranean evergreen tree (Olea europaea)(Springer-Verlag, 2016-06) Ventre-Lespiaucq, Agustina B.; Escribano Rocafort, Adrián Gaspar; Delgado Sáez, Juan Antonio; Jiménez Escobar, María Dolores; Rubio de Casas, Rafael; Granado Yela, Carlos; Balaguer Núñez, LuisThe light environment within a tree crown can be characterized by specific variation patterns arising from the structural features of the crown. Within-crown light variation patterns can be important for plant productivity, but this has yet to be assessed in natural settings. The spatio-temporal variations of direct and diffuse photosynthetic photon flux density (PPFD), their proportions and sunfleck frequency within the crowns of isolated adult wild olive trees (Olea europaea L.) were investigated. Trees growing in contrasting Mediterranean conditions (continental vs. coastal) at the same latitude were compared. Instantaneous diffuse and total PPFD were measured with sunshine sensors in three crown layers (outer-, middle- and inner-crown) in the south-facing part of the crown, at two points of the diurnal (mid-morning and midday) and seasonal (summer and winter) cycles. Direct PPFD and the proportion of direct to total PPFD vary diurnally within the crown as a result of an increase in sunfleck requency during midday and in self-shading during mid-morning, in both summer and winter conditions. Conversely, the lack of seasonal variation in the three light attributes is better explained by a greater average crown transmittance in winter conditions. The interplay between crown architecture heterogeneity and varying solar position renders identifiable patterns of temporal variations in the light environment within tree crowns. These patterns suggest that trees can benefit from the light heterogeneity typical of Mediterranean environments by developing conservative architectural layouts.
- PublicationCommunity ontogeny at the roadside: Critical life-cycle events throughout a sequential process of primary colonization(Wiley, 2014) Magro, Sandra; Jiménez Escobar, María Dolores; Casado González, Miguel Ángel; Mola, Ignacio; Arenas Escribano, Juan María; Martín Duque, José Francisco; Vazquez, Ana; Balaguer Núñez, LuisQuestions: How does the response to environmental filters change across the life cycle of pioneer plants through the early process of community assembly? Is there a threshold at any of the life-history stages during roadcut primary colonization? Location: A very steep, sun-exposed, low-fertility and low water retention roadcut in a Mediterranean continental site in Madrid, central Spain. Methods: We tracked density of individuals, plant cover, species richness and community composition throughout the sequential process of primary colonization of a newly-exposed roadcut surface. We monitored from seed arrival to seedling emergence, seedling survival and plant growth across species over two growing seasons. We manipulated the intensity of environmental filters in 12 experimental plots (10 9 8 m) following a full-factorial design of two treatments (topsoil spreading and shallow tillage). Results: The response to environmental filter manipulation varied throughout the individual life cycle. Under an equal seed rain, the higher carrying capacity caused by topsoil spreading gave rise to the emergence of a larger number of species, which either persisted or occasionally appeared in some of the stages of the early community assembly. Further, topsoil spreading enhanced seedling survival across species, as well as subsequent plant growth. We therefore detected two life-history stages acting as thresholds in plant community assembly due to an ontogenetic niche shift across species. The first, at seedling emergence, in response to environmental cues with lasting consequences in community composition and species richness; and the second, at the transition to the adult stage in response to local resource availability, with consequences in subsequent plant growth and community cover. Conclusions: During primary colonization, ontogenetic development of pioneers was paralleled by the action of environmental filters throughout the community assembly process. On roadcuts, the confluence of both processes gives rise to a community ontogeny marked by two thresholds determining community richness and cover under Mediterranean conditions. Our findings shed light on the underlying mechanisms involved in technical solutions, such as topsoil spreading, and provide a more efficient approach to roadside restoration.
- PublicationUse of restoration plantings to enchance bird seed dispersal at the roadside: failures and prospects(Taylor & Francis, 2015-10) Torre Ceijas, Rocío de la; Jiménez Escobar, María Dolores; Ramírez García, Álvaro; Mola, Ignacio; Casado González, Miguel Ángel; Balaguer Núñez, LuisPlantings are commonly used in roadside reclamation for ornamental purposes and for increasing slope stability and road safety. However, the role of these plantings in restoring ecological processes, such as seed dispersal, has received little attention. We carried out a study to assess the potential role of plantings on roadside embankments to attract frugivorous birds and to enhance seed dispersal mediated by birds from the surrounding landscape. We examined: (1) bird species richness and abundance; (2) patterns of avian spatial distribution within embankments and (3) seed dispersal mediated by birds. Bird richness and abundance did not differ between embankments with and without plantings. However, birds were not distributed randomly within embankments, with levels of species richness and abundance for facultative frugivorous between 4.8–8 times higher in areas closer to plantings. An analysis of bird droppings showed that birds only dispersed seeds of the planted species since no seeds of woody plants from matrices were detected. These results suggest that plantings acted as selective birdattractors, providing food and perches for frugivorous species. Nevertheless, the scarcity of seed-dispersing birds in the surrounding agricultural landscape prevented plantings from enhancing seed dispersal and connectivity to adjacent habitat.