Vegetation dynamics of ephemeral and perennial streams in mountainous headwater catchments

Pattiyage I.A. Gomes, Onyx W.H. Wai, Ganegoda K. Dehini

Research output: Journal article publicationJournal articleAcademic researchpeer-review

Abstract

Ephemeral and perennial streams of mountainous catchments in Sabaragamuwa Province of Sri Lanka and Hong Kong of China were studied for two years on vegetation dynamics. Each year, sampling was conducted during a period when ephemeral streams had low surface flows. Sampling was realized contiguously using belt transects. The standing crop biomass (hereafter biomass) of herbaceous vegetation in ephemeral channels was comparatively lower than perennials and so was the herb diversity. Herb diversity showed a peak from 1.5 to 4.5 m from the centerline/thalweg of ephemeral and perennial streams. Out of 24 herbs, only three were common for both. A peak herb biomass zone was observed in perennials in the same region where diversity peaked. In ephemerals, herb biomass increased laterally up to ∼1.5 m, and was constant thereafter. Seedling experiment results tallied with the field diversity observations of both stream types, and suggested that seed dispersion was the main reason for herb colonization. Furthermore, it showed sapling emergence to be significantly higher in perennials than ephemerals. Return period of annual maximum monthly rainfall was a strong indicator of age of trees in ephemeral streams, and elucidated the possibility of hindcasting past flow episodes. Electrical conductivity was significantly high in ephemeral streams among all the water quality parameters. The contents of the water nutrients were approximately the same in both stream types. While recommending further studies on eco-hydrology of ephemerals, we recognize ephemeral streams to be valuable references in climate change studies due to their responsiveness and representativeness in long term hydrological changes.

Original languageEnglish
Pages (from-to)1684-1695
Number of pages12
JournalJournal of Mountain Science
Volume17
Issue number7
DOIs
Publication statusPublished - 1 Jul 2020

Keywords

  • Biomass
  • Ephemeral streams
  • Herb diversity
  • Mountainous areas
  • Perennial streams
  • Sri Lanka

ASJC Scopus subject areas

  • Global and Planetary Change
  • Geography, Planning and Development
  • Geology
  • Earth-Surface Processes
  • Nature and Landscape Conservation

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