Soliveres Santiago, García-Palacios Pablo, Maestre Fernando T, Escudero Adrián, Valladares Fernando
Área de Biodiversidad y Conservación, Departamento de Biología y Geología, Escuela Superior de Ciencias Experimentales y Tecnología, Universidad Rey Juan Carlos, 28933 Móstoles, Spain.
Área de Biodiversidad y Conservación, Departamento de Biología y Geología, Escuela Superior de Ciencias Experimentales y Tecnología, Universidad Rey Juan Carlos, 28933 Móstoles, Spain ; Natural Resource Ecology Laboratory, Colorado State University, Fort Collins, CO 80523, USA ; Department of Biology, Colorado State University, Fort Collins, CO 80523, USA.
J Arid Environ. 2013 Apr 1;91:104-112. doi: 10.1016/j.jaridenv.2012.12.011.
We evaluated the net outcome of the interaction between the shrub , our target plant, and different herbaceous neighbours in response to changes in the magnitude and frequency of rainfall events during three years. The experiment was conducted in natural and anthropogenic grasslands dominated by a perennial stress-tolerator and ruderal annual species, respectively. In spite of the neutral or positive effects of neighbours on water availability, neighbouring plants reduced the performance of juveniles, suggesting competition for resources other than water. The negative effects of grasses on the photochemical efficiency of juveniles decreased with higher water availabilities or heavier irrigation pulses, depending on the grassland studied; however, these effects did not extent to the survival and growth of juveniles. Our findings show the prevalence of competitive interactions among the studied plants, regardless of the water availability and its temporal pattern. These results suggest that positive interactions may not prevail under harsher conditions when shade-intolerant species are involved. This study could be used to further refine our predictions of how plant-plant interactions will respond to changes in rainfall, either natural or increased by the ongoing climatic change, in ecosystems where grass-shrubs interactions are prevalent.
我们评估了作为目标植物的灌木与不同草本邻居之间相互作用的净结果，以响应三年间降雨事件强度和频率的变化。该实验分别在以多年生耐胁迫植物和一年生杂草为主的天然草原和人为干扰草原中进行。尽管邻居对水分可利用性有中性或积极影响，但邻近植物降低了幼苗的表现，表明存在对水分以外资源的竞争。根据所研究的草原类型，随着水分可利用性增加或灌溉脉冲增强，草本植物对幼苗光化学效率的负面影响会降低；然而，这些影响并未扩展到幼苗的存活和生长。我们的研究结果表明，在所研究的植物之间，无论水分可利用性及其时间模式如何，竞争相互作用都普遍存在。这些结果表明，当涉及不耐荫物种时，在更恶劣的条件下，积极相互作用可能并不占主导。这项研究可用于进一步完善我们对植物 - 植物相互作用如何响应降雨变化（无论是自然降雨变化还是当前气候变化导致的降雨增加）的预测，这些降雨变化发生在草本 - 灌木相互作用普遍存在的生态系统中。
