Abiotic constraints at the upper boundaries of two Rumex species on a freshwater flooding gradient
نویسندگان
چکیده
1 Competition is widely thought to be responsible for constraining species limits at the favourable ends of freshwater flooding gradients. However, field studies testing this idea rarely consider the role of competition beyond a species’ field distribution limits. 2 To test whether species distributions are, instead, constrained by physiological limits, and only narrowed by biotic interactions, we measured the effect of competition on survival and fecundity of Rumex crispus and Rumex palustris within and above their distribution range along an elevation gradient in a river floodplain. 3 Flooding reduced the fitness of both species at the lowest elevations. A decline in fitness was also noticed at the two highest elevations in control as well as in removal plots, although standing crop measurements indicated that conditions here were the most favourable. 4 Both leaf herbivore damage and likeliness of drought increased with elevation. Because herbivore damage only reinforced prevailing abiotic influences, drought appeared to be the strongest constraint at higher positions. 5 Competition merely narrowed both species’ physiological ranges by displacing them downwards from their optimum and maximum elevation. The displacement was strongest for the weak competitor Rumex palustris . 6 Our study provides experimental field evidence for earlier suggestions that both ends of a species niche can be defined in hydrological terms. It thus indicates that spatial variability in water availability may segregate species niches and thereby promote species richness in plant communities.
منابع مشابه
Mechanisms mediating plant distributions across estuarine landscapes in a low-latitude tidal estuary.
Understanding of how plant communities are organized and will respond to global changes requires an understanding of how plant species respond to multiple environmental gradients. We examined the mechanisms mediating the distribution patterns of tidal marsh plants along an estuarine gradient in Georgia (USA) using a combination of field transplant experiments and monitoring. Our results could n...
متن کاملTwo Rumex species from contrasting hydrological niches regulate flooding tolerance through distinct mechanisms.
Global climate change has increased flooding events, which affect both natural vegetation dynamics and crop productivity. The flooded environment is lethal for most plant species because it restricts gas exchange and induces an energy and carbon crisis. Flooding survival strategies have been studied in Oryza sativa, a cultivated monocot. However, our understanding of plant adaptation to natural...
متن کاملBiostratigraphy of the Bazehowz Formation at its Type section, South West Mashhad based on plant macrofossils
Jurassic deposits are well exposed in the Bazehowz area, South west of Mashhad city, East Alborz, Iran. It contains plant macrofossilsbelonging to eighteen species of eleven genera of various orders such as Equisetales, Filicales, Bennettitales, Cycadales,Corystospermales, Caytoniales, Ginkgoales and Pinales. Two biozones were recognized in the type section of Bazehowz Formation.Biozone I is an...
متن کاملLearning from nature: the use of non-model species to identify novel acclimations to flooding stress
Excess water in the form of waterlogged soil or deeper submergence (generically termed 'flooding') influences plant growth, survival and species distribution in many natural ecosystems. It also has a negative impact on crop growth and yield since many agricultural species are flooding intolerant. The often devastating effect of flooding on plant performance is related to its interference with g...
متن کامل