1,721,024 research outputs found
Plant functional traits and species coexistence in variable environments
No full textComunicación oral presentada en BES Annual Meeting 2018 16-19 December 2018, Birmingham UKN
Influence of global change drivers on fine scale determinants of soil fauna
No full textComunicación oral (TS.14-O-12) presentada en the 1st Meeting of the Iberian Ecological Society (SIBECOL) & XIV AEET meeting. Barcelona, Spain, 4th – 7th February 2019Soil fauna plays an essential role for nutrient cycling processes, but the drivers promoting changes in its abundance and diversity, particularly within a global change context are largely unknown. In spring 2016, we built a rainfall exclusion experiment (30% rainfall reduction) to explore soil fauna responses to simulated climate change in a mixed oak forest of southern Spain invaded by the exotic soil-borne pathogen Phytophthora cinnamomi. We identified soil fauna groups at the suborder taxonomic level and its trophic position at the beginning of the experiment and after one year in both experimental and control plots. We then analysed the effect of the rainfall reduction treatment on temporal changes in the abundance and diversity of soil measofauna. We also explored statistical correlations with fine-scale biotic and abiotic parameters by means of structural equation models. Primarily, we observed that one year of experimental rainfall reduction strongly decreased predator abundance but not detritivore abundance. Moreover, light availability, tree defoliation and the abundance of P. cinnamomi were identified as the main drivers of the changes in the abundance of particular detritivore groups. Our results demonstrate rapid responses of the abundance and composition of the litter mesofauna to climate change-related drought, with the organisms in the higher trophic levels being the more susceptible to increasing dryness. Multiple tree and litter characteristics influenced litter fauna abundance at local scale, suggesting that global change drivers as climate change and invasive exotic species are modifying these complex relationships.N
Phenological responses to climate change in communities of plants species with contrasting functional strategies
No full textComunciación oral presentada en Ecoflor2019. XVI Annual Meeting of the Spanish Group for Floral Ecology (2019) 14-16 marzo, Granada.-- el libro de abstract se puedes descargar en https://consigna.ugr.es/f/MW9bpu6orIVigcBU/EcoFlor2019.pdfUnderstanding how plant species will respond to the new environmental conditions predicted by global change models is nowadays a crucial research aim in ecology. Variation in plant reproductive phenology is an important plant feature to evaluate species’ responses to climate change as it has direct implications for community dynamics and ecosystem functioning. However, to what extent coexisting plant species are sensitive to different climate scenarios in order to maintain fitness homeostasis is a question that remains largely untested. In this study, we carried out an experiment under controlled conditions using five annual plant species co-occurring in Mediterranean grasslands of oak-Savannahs (Dehesas) that spanned a wide range of different functional strategies. Seedlings of these species were transplanted into mesocosms filled with a mixed substrate of sterile sand-loam and peat. Each mesocosms was considered as a community of 18 individuals in which its spatial design allows us to target specific individuals with varying identity and number of competitors. This design was done to decompose the direct effect of environmental conditions and the indirect effect of neighbors (including both intra and interspecific competition) on plant performance. A total of 144 communities were equally distributed into two glasshouse units subjected to different temperature ranges, using a randomized block design with four climatic treatments: a ´control` treatment (simulating current averaged meteorological conditions in Mediterranean savanna-like systems), a ´dry` treatment (with a reduction of 33% in watering, anticipating future predictions of climate change models), a ´warming` treatment (with an increase of 3-4ºC), and a ´dry+warming` treatment (to evaluate the interactive effects of both sources of abiotic stress). This study will significantly contribute to advance our understanding on how species’ responses to different climate change scenarios will modify community composition, and target phenological traits as key indicators of species performance and community dynamics.N
Are northern-edge populations of cork oak more sensitive to drought than those of the southern edge?
No full text8 páginas.- 5 figuras.- 1 tabla.- 77 referencias.- Supplementary material related to this article can be found, in the online version, at Doi: https://doi.org/10.1016/j.envexpbot.2019.04.011The changes in climate registered at the planetary scale threaten the persistence of current populations for many plant species, with effects particularly evident at the edges of species distributions. However, intraspecific differences in functional traits could modulate the plant responses to the expected increase in drought. Using a traitbased approach, we evaluated under controlled conditions how Quercus suber seedlings from the latitudinal edges of the distribution range of the species respond to different watering treatments in terms of vegetative growth and biomass allocation. In addition, we simulated an extreme drought by stopping watering until death to determine chemical and physiological traits under drought stress and to identify which morphological traits were more associated to drought resistance (expressed as survival time without watering). Seedlings from the northern provenance presented higher aboveground biomass allocation (i.e. shoot length and biomass allocation to shoot and leaves), while the southern ones were characterised by longer roots and higher biomass allocation to roots. Under extreme drought, seedlings from the southern provenance maintained higher photosynthetic rates than northern seedlings and were able to modulate their water-use efficiency (estimated from δ13C) depending on environmental conditions, which allowed them to survive for a longer period. Finally, drought resistance was partially explained by the plant biomass allocation pattern. Traits related to growth in height and light interception were negatively related with drought resistance, whereas traits involving investment in root biomass were positively related with resistance. These geographical differences evidence a local adaptation to drought at the southern edge of Q. suber distribution. Our results highlight the importance of the conservation of
the genetic resources that peripheral populations harbour at distribution edges.This research was funded by a Large Research Grant (6007210) awarded from the British Ecological Societyand by a fellowship Plan 6-UJA (EI_RNM4_2017) to L.M. I.M.P.R and L.G.A. also thank support from the MICINN projects DECAFUN(CGL2015-70123-R) and INTERCAPA (CGL-2014-703 56739-R)Peer reviewe
Soil fauna modulates the effect of experimental drought on litter decomposition in forests invaded by an exotic pathogen
No full text7 figuras.- 1 tablas.- referencias.- Data and associated code to reproduce the results are stored in Figshare (https://figshare.com/s/6ad186835f2ce6527ffa). Data is currently under embargo and it will be released upon publication. Nonetheless, data can be available under reviewer request if needed.Litter decomposition is a fundamental process for nutrient cycling and C fluxes between terrestrial ecosystems and the atmosphere. Multiple factors such as environmental conditions, litter quality, and decomposer organisms are known to influence this ecological process in direct and indirect ways. However, it remains poorly understood to what extent this entangled bank of complex interactions can be disrupted by several global change drivers such as climate change and invasive species.
Here we report main findings from a litter decomposition experiment conducted in a natural mixed forest invaded by Phytophthora cinnamomi, an exotic oomycete well-known for causing tree disease and forest decline. In two Mediterranean forest types (namely woodland and closed forest), we first built a rainfall exclusion infrastructure to reduce natural precipitation by 30 %. Then, we followed the spatial variation in C and N leaf litter dynamics as well as the abundance of the exotic oomycete P. cinnamomi during 18 months under both control and rainfall exclusion conditions using a litter bag methodology with different mesh sizes to further evaluate the indirect role of mesofauna abundance and diversity in litter C and N temporal dynamics.
Significant reductions in soil moisture produced by the experimental rainfall exclusion increased directly C litter loss with time, and indirectly via increases in overall mesofauna abundance and changes in the ratio between predators and decomposers. N litter dynamics were in contrast modulated mainly by initial litter quality. Surprisingly, P. cinnamomi abundance did not correlate with variation in initial litter quality as previously suggested, but we found that the exotic oomycete was negatively correlated with both decomposer and predator abundances. These results suggest it might participate indirectly in litter decomposition dynamics through the biotic soil component.
Synthesis: Contrary to expected, our results show that a moderate but realistic rainfall reduction can accelerate the litter decomposition process. It also points out to litter fauna as a key component modulating the indirect impacts of global change drivers on litter decomposition.This study was funded by the MICINN projects INTERCAPA (CGL2014-56739-R) and MICROFUN (RTI2018-094394-B-I00). PH was supported by a FPI-MICINN grant. LM was supported by the fellowship IV2 from VI-PPIT (Univ. Sevilla) and the project PID2019-108288RA-I00 (MINECO). OG acknowledges financial support provided by the Spanish Ministry of Economy and Competitiveness (MINECO) and by the European Social Fund through the Ramón y Cajal Program (RYC-2017-23666)Peer reviewe
Evidence for antagonistic effects of climate change and exotic pathogens on regeneration of Mediterranean forests
No full text15 páginas.- 6 figuras.- 2 tablas.- referencias.- Additional supporting information can be found online in the Supporting Information section at the end of this articleUnderstanding the interactive effects of global change drivers on tree demography is fundamental for realistic predictions of future forest dynamics. Multiple studies have shown increasing drought and exotic pathogens to severely threaten forest persistence by increasing mortality and decreasing growth of adult trees. However, much less is known about their effects on regeneration, and how they might affect seedling performance in additive and non-additive (synergistic or antagonistic) ways.Here we aimed to fill this gap by experimentally exploring the effects of increasing drought and soil-borne pathogens on tree regeneration in two types of mixed oak forests (Quercus suber-Q. canariensis and Q. suber-Olea europaea) invaded by the exotic soil-borne oomycete Phytophthora cinnamomi, one of the most aggressive plant pathogens on earth. We conducted a seed sowing experiment with oomycete-specific fungicide taking advantage of rainfall exclusion infrastructures that excluded 30% of the annual rainfall, simulating predictions of climate change models for Mediterranean systems. Seedling emergence, survival and growth of the three tree species were followed during 3 years.We found that neutral or positive drought effects on regeneration dominated over negative effects in the tree community. Moreover, most positive drought effects on the dominant species (Q. suber) were not direct, but indirectly mediated by soil-borne pathogens. This was shown by the fact that positive drought effects disappeared with fungicide application.Synthesis: Overall, our results suggest that rainfall reductions predicted by climate change models for the Mediterranean region might have minor direct negative effects on early regeneration of tree species, but could play a major indirect role by limiting the negative effects of exotic pathogens on highly susceptible tree species. These findings highlight that antagonisms among global change drivers should be recognized as important forces that might slow down the current loss of tree health.This study was funded by the MICINN projects INTERCAPA (CGL2014-56739-R) and MICROFUN (RTI2018-094394-B-I00). P.H. was supported by a FPI-MICINN grant. L.M. was supported by the fellowship IV2 from VI-PPIT (Univ. Sevilla) and the project PID2019-108288RA-I00 (MINECO). O.G. acknowledges financial support provided by the Spanish Ministry of Economy and Competitiveness (MINECO) and by the European Social Fund through the Ramón y Cajal Program (RYC-2017-23666)Peer reviewe
Efectos del cambio climático sobre la regeneración del bosque mediterráneo: una aproximación experimental
Get PDFTesis Univ. Granada. Departamento de Ecología. Leída el 24 de septiembre de 201
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Phenological responses to climate change in communities of plants species with contrasting functional strategies
No full text10 páginas.- 6 figuras.- 1 tabla.- 60 referencias.- Supplementary material related to this article can be found, in the online version, at doi:https://doi.org/10.1016/j.envexpbot.2019.103852.- This article is part of a special issue entitled “The climatic challenge: learning from past survivors and present outliers”.Understanding why co-occurring plant species show differential phenological sensitivities to climate fluctuations, and more specifically to the joint variation in temperature and precipitation, is critical to make accurate predictions on how climate change could alter community dynamics and ecosystem functioning. However, the role that some relevant functional traits involved in resource uptake and/or stress tolerance could play on these inter-specific differences in phenological sensitivity remains largely unknown. In this study we evaluated experimentally how five co-occurring herbaceous species with contrasting functional strategies respond to current and ongoing climatic scenarios of increased temperature, decreased water availability and both abiotic changes acting interactively. To decompose the direct effect of climate change and the indirect effect of neighbors on plant performance and reproductive phenology, each of the five species was exposed to a density gradient of competitor species. Although the study species were more sensitive to changes in temperature than in water availability, the combined effect of both abiotic cues triggered very heterogeneous responses. Species with higher SLA values were particularly sensitive to climate change, delaying their reproduction and lengthening their flowering period under warmer scenarios while maintaining a high plant growth rate. In contrast, the species with the lowest SLA values exhibited less phenological variability to climate alterations, but they were more strongly affected by neighbor density compared to species with opposite trait values. These species-specific responses to climatic shifts altered the synchrony of phenological events at the community level. The most important changes appeared under the two scenarios of increased temperature, where 4 out of 5 species overlapped their flowering periods. Our findings indicate that the ongoing scenarios of increasing temperature and aridity could disrupt the phenological asynchrony within communities, and highlight the necessity of considering the interactive effects of temperature and precipitation to obtain an overall picture of climate change predictions on plant phenology and population dynamics.This study was entirely funded by the MICINN project DECAFUN (CGL2015-70123-R). I.M.P.R was funded by a “Ramón and Cajal” contract (RYC-2013-13937) and LM by a Plan 6-UJA fellowship (EI_RNM4_2017).Peer reviewe
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