Different responses of alpine plants to nitrogen addition: effects on plant-plant interactions

Abstract

The different responses of plant species to resource stress are keys to understand the dynamics of plant community in a changing environment. To test the hypothesis that nitrogen (N) increase would benefit N competitive species, rather than N stress-tolerant species, to compete with neighbours, we conducted an experiment with neighbour removal, N addition and soil moisture as treatments in an alpine grassland on the southeastern Tibetan Plateau. Both growths and competitive-response abilities (CRA, the ability to tolerate the inhibitory effects of neighbors) of Kobresia macrantha, Polygonum viviparum and Potentilla anserine in wet site were facilitated by N addition, conversely, both growths and CRA of Taraxacum mongolicum and Ligularia virgaurea were suppressed by N addition, indicating that the responses of CRA of target species under N addition were consistent with the N utilization strategies of them. Moreover, the facilitative effects of N addition on competitive-response abilities of Kobresia macrantha and Polygonum viviparum were not found at the dry site, illustrating that soil moisture can alter the changes of neighbour effects caused by N addition. Life strategy of dominant species in plant community on the undisturbed southeastern Tibetan Plateau may shift from N stress-tolerant to N competitive, if the N increases continuously.

Life history responses of two ephemeral plant species to increased precipitation and nitrogen in the Gurbantunggut Desert

“…Water is not only a material for photosynthesis (Maberly, 2014), but also a solvent for nitrogen (Gebauer & Ehleringer, 2000; Lloret, Casanovas & Penuelas, 2010). Similarly, the effects of precipitation plus nitrogen on plants have been reported largely in terms of plant richness (McHugh et al., 2017; Simkin et al, 2016), diversity (Bobbink et al, 2010; McHugh et al, 2017), community coverage (McHugh et al, 2017), community biomass (Xu et al, 2018), and plant-plant interactions (Wang et al, 2016a; Wang et al., 2016b). However, the effects of precipitation plus nitrogen on whole life history have rarely been reported.…”

“…Thus, ephemeral plants are extremely sensitive to climate change. Previous research on the effects of precipitation and nitrogen on ephemeral plants has focused primarily on plant survival, biomass accumulation (Lu et al., 2014) and nutrient use (Wang et al, 2016a; Wang et al., 2016b). The information about plant responses to climate change throughout the entire life history is lacking.…”

Disentangling anthropogenic drivers of climate change impacts on alpine plant species: Alps vs. Mediterranean mountains

“…How sensitive ecosystems, plant communities and individual species respond to inputs of atmospheric nitrogen is a complex matter. It depends on multiple environmental variables, such as phosphorus limitation, soil pH, soil moisture, and the thermal conditions (Porter et al 2013, Simkin et al 2016, Wang et al 2016a. Average estimates of critical loads, i.e.…”

Effect of insect herbivory on plant community dynamics under contrasting water availability levels

“…These effects can emerge through changes in plant traits influencing herbivore density and feeding behaviours to ultimately affect plant damage (Dinnage, ; Unsicker, Oswald, Köhler, & Weisser, ). Interactions between focal plants and their neighbours appear, therefore, to be highly context‐dependent (Wang, Luo, Yang, Mou, & Mo, ). Experimental studies exploring these processes in response to both biotic and abiotic factors in species‐rich plant communities remain scarce.…”