Belowground niche partitioning is maintained under extreme drought

Belowground niche partitioning presents a key mechanism for maintaining species coexistence and diversity. Its importance is currently reinforced by climate change that alters soil hydrological conditions. However, experimental tests examining the magnitude of its change under climate change are scarce. We combined measurements of oxygen stable isotopes to infer plant water-uptake depths and extreme drought manipulation in grasslands. Belowground niche partitioning was evidenced by different water-uptake depths of co-occurring species under ambient and extreme drought conditions despite an increased overlap among species due to a shift to shallower soil layers under drought. A co-occurrence of contrasting strategies related to the change of species water-uptake depth distribution was likely to be key for species to maintain some extent of belowground niche partitioning and could contribute to stabilizing coexistence under drought. Our results suggest that belowground niche partitioning could mitigate negative effects on diversity imposed by extreme drought under future climate.publishedVersio

Protection of the vascular endothelium in experimental situations

One of the factors proposed as mediators of vascular dysfunction observed in diabetes is the increased generation of reactive oxygen species (ROS). This provides support for the use of antioxidants as early and appropriate pharmacological intervention in the development of late diabetic complications. In streptozotocin (STZ)-induced diabetes in rats we observed endothelial dysfuction manifested by reduced endothelium-dependent response to acetylcholine of the superior mesenteric artery (SMA) and aorta, as well as by increased endothelaemia. Changes in endothelium-dependent relaxation of SMA were induced by injury of the nitric oxide radical (·NO)-signalling pathway since the endothelium-derived hyperpolarising factor (EDHF)-component of relaxation was not impaired by diabetes. The endothelial dysfunction was accompanied by decreased ·NO bioavailabity as a consequence of reduced activity of eNOS rather than its reduced expression. The results obtained using the chemiluminiscence method (CL) argue for increased oxidative stress and increased ROS production. The enzyme NAD(P)H-oxidase problably participates in ROS production in the later phases of diabetes. Oxidative stress was also connected with decreased levels of reduced glutathione (GSH) in the early phase of diabetes. After 10 weeks of diabetes, adaptational mechanisms probably took place because GSH levels were not changed compared to controls. Antioxidant properties of SMe1EC2 found in vitro were partly confirmed in vivo. Administration of SMe1EC2 protected endothelial function. It significantly decreased endothelaemia of diabetic rats and improved endothelium-dependent relaxation of arteries, slightly decreased ROS-production and increased bioavailability of ·NO in the aorta. Further studies with higher doses of SMe1EC2 may clarify the mechanism of its endothelium-protective effect in vivo

Cechy funkcjonalne i plastyczne roślin w badaniach ekologicznych i edukacji

Plant functional traits are any morphological, physiological and phenological features, which indirectly affect plant fitness through their three basic components of plant individual performance - growth, reproduction and survival. These features represent also a keystone for plant functional groups, which are similar in three aspects - function on the level of organism, response to environmental factors and effect on ecosystems. Functional approach in ecology and vegetation study enables to evaluate plant communities on the base of species function in a community, and to relate functional structure of plant communities to particular environmental gradients. Species plasticity has many aspects that mirror species adaptations to the environmental conditions and which then also translate into functional structuring of plant communities. This approach is thus a novel and exciting mode how to carry on plant ecology, both in research and education at universities.Charakterystyczna funkcjonalność roślin zależy od ich cech morfologicznych, fizjologicznych i fenologicznych, które pośrednio wpływają na kondycję roślin poprzez trzy podstawowe elementy ich indywidualnego rozwoju, tj. wzrost, reprodukcję i przetrwanie. Cechy te stanowią również podstawę funkcyjnych grup roślinnych, które są podobne w trzech aspektach - funkcje na poziomie organizmu, odpowiedź na czynniki środowiskowe i wpływ na ekosystemy. Podejście funkcjonalne w ekologii i w badaniach roślin umożliwia ocenę zbiorowisk roślinnych w oparciu o funkcje gatunków w społeczności i odniesienie funkcjonalnej struktury zbiorowisk roślinnych do poszczególnych gradientów środowiskowych. Plastyczność gatunków ma wiele aspektów, które odzwierciedlają ich przystosowanie do warunków środowiskowych, a które następnie przekłada się także na funkcjonalną strukturę zbiorowisk roślinnych. Takie podejście jest więc nowym i interesującym sposobem rozumienia ekologii roślin, znajdującym zastosowania zarówno w badaniach, jak i w edukacji uniwersyteckiej

Functional trait effects on ecosystem stability: assembling the jigsaw puzzle

Acknowledgments This study is the result of an international workshop financed by the Valencian government in Spain (Generalitat Valenciana, reference AORG/2018/) and was supported by Spanish Plan Nacional de I+D+i (project PGC2018-099027-B-I00). E.V. was supported by the 2017 program for attracting and retaining talent of Comunidad de Madrid (no. 2017-T2/ AMB-5406).Under global change, how biological diversity and ecosystem services are maintained in time is a fundamental question. Ecologists have long argued about multiple mechanisms by which local biodiversity might control the temporal stability of ecosystem properties. Accumulating theories and empirical evidence suggest that, together with different population and community parameters, these mechanisms largely operate through differences in functional traits among organisms. We review potential trait-stability mechanisms together with underlying tests and associated metrics. We identify various trait-based components, each accounting for different stability mechanisms, that contribute to buffering, or propagating, the effect of environmental fluctuations on ecosystem functioning. This comprehensive picture, obtained by combining different puzzle pieces of trait-stability effects, will guide future empirical and modeling investigations.Depto. de Biodiversidad, Ecología y EvoluciónFac. de Ciencias BiológicasTRUEpu