关键词: 水位, 基质异质性, 挺水植物, 克隆性, 觅食行为, 荆三棱(Scirpus yagara)

Abstract:

Environmental heterogeneity affects the performance of clonal aquatic plants. Few researchers integrated two aspects of heterogeneity into the study of clonal plant ecology. The aims of the present study are to (i) test whether different substrate heterogeneity and submergence exert similar effects on plant performance and (ii) explore the foraging behaviour.

In this study, Scirpus yagara was subjected to multiple levels of substrate heterogeneity and submergence. Substrate treatments included one homogeneous substrate and three heterogeneous substrates (two-patch, four-patch and eight-patch). Water level treatments included 0, 10 and 30 cm. Traits including ramet number, generation number, leaf number, bulb number, ramet height, culm length, rhizome length, clonal radius, spacer length, spacer thickness, total biomass, biomass of bulbs and biomass per bulb were measured.

Deeper water levels significantly reduced variables associated with growth such as ramet number, generation number, leaf number and bulb number, while substrate patchiness induced significant variations in traits such as spacer length and spacer thickness. Significant interactive effects of the two factors were found for ramet number, leaf number and spacer length. Scirpus yagara showed colonization towards the lake sediment patch in two-patch and four-patch substrates, and more structures were placed in the lake sediment patch. Especially for the two-patch substrate, all structures occupied the lake sediment patch. Two-sided intrusion was observed in the eight-patch substrate, which induced an even allocation of structures in different patches. The foraging behaviour was correlated with the patch size.

Key words: water level, substrate heterogeneity, emergent aquatic plant, clonality, foraging behaviour, Scirpus yagara