Effects of hydrology and competition on plant growth in a freshwater marsh of northeast China

Abstract

Hydrology and competition are major determinants of plant zonation patterns in wetlands. We conducted a pot experiment to investigate effects of water levels on plant growth of two dominant species from the Sanjiang Plain (Deyeuxia angustifolia and Carex lasiocarpa) in monoculture and mixtures (i.e., 2:1, 1:1, and 1:2 mixtures of C. lasiocarpa and D. angustifolia). Water level had significant effects on the biomass of both species (p < 0.05). The aboveground biomass of C. lasiocarpa increased with decreasing water level in both monoculture and mixtures and the same was true for belowground biomass in monoculture. Waterlogging (10 cm water level) and natural drought reduced the aboveground and belowground biomass of D. angustifolia in monoculture and waterlogging (20 and 10 cm water levels) also reduced the aboveground biomass in mixtures. The relative yield of C. lasiocarpa was greater than 1.0 in the 1:1 mixture (t ¼ 3.49) and the 1:2 mixture (t ¼ 6.63) at 20 cm water level (i.e., the performance of individuals was better in mixtures than that in the monoculture), and the same was true for D. angustifolia in the 2:1 mixture (t ¼ 10.23) and the 1:1 mixture (t ¼ 4.12) at À10 cm water level. The relative yield of C. lasiocarpa increased with increasing water level in the 1:1 and 1:2 mixtures but decreased for D. angustifolia in the 2:1 mixture. Moreover, the species with smaller initial proportion usually had higher relative yield in mixtures. This would tend to promote the coexistence of these two species. Our results suggest that hydrologic regime change has the potential to produce marked influences on plant productivity and ecosystem carbon budget in the Sanjiang Plain. Moreover, competition is an additional important determinant of plant distribution and community structure in this area.

Response of Plant Height, Species Richness and Aboveground Biomass to Flooding Gradient along Vegetation Zones in Floodplain Wetlands, Northeast China

“…For each community, aboveground biomass was not affected by water table depth ( Fig 4 ). This contrast with the conclusions of artificial simulation experiment implemented by Zhang et al [ 40 ] and Shi et al [ 30 ], in which water level significantly affect aboveground biomass of dominant species C . lasiocarpa and C .…”

Modeling the Spatial Distribution of Three Typical Dominant Wetland Vegetation Species’ Response to the Hydrological Gradient in a Ramsar Wetland, Honghe National Nature Reserve, Northeast China

“…The vegetation composition and structure generally show a spatial differentiation pattern along a hydrological gradient in these freshwater marshes. Specifically, the zonation of the vegetation, comprising wet meadows and permanently inundated marshes, is generally dominated by high-elevation species Calamagrostis angustifolia and low-elevation species Carex pseudocuraica, respectively, whereas the mid-marsh zones (the seasonally inundated marshes) are co-dominated by mid-elevation species Carex lasiocarpa and Glyceria spiculosa [31][32][33]. The main environmental factors affecting the distribution of vegetation are the water level and the soil moisture contents.…”

The Effects of Water Levels and Interspecific Competition on Two Carex Species in a Temperate Wetland of Northeast China

“…We selected three parameters to represent the fitness of different species: (1) total dry biomass of the whole plant; (2) single shoot dry biomass, mean shoot biomass of single ramets that had more than three leaves, and (3) propagule amount, including all ramets, buds, and rhizomes, representing clonal growth ability. In order to further evaluate the relative competition ability of two species, we used relative yield (RY, [9,25]) as follows:…”

“…On one hand, flooding causes excessive depletion of soil oxygen, which changed soil redox conditions [6]. As a consequence, leaf stomatal conductance, photosynthesis, and biomass were influenced by inundation directly or indirectly [7][8][9]. On the other hand, the effects of the interactions between different wetland species are numerous.…”