Composition and some ecophysiological characters of water catchment area’s vegetation of Geger Spring, Bantul, Yogyakarta, Indonesia

Abstract

Water debit of GegerSpring, Pundong, Bantul, Yogyakartahascalled attention due to decreasing of water resource within 8 years lately. Water Catchment Area (WCA) of Geger Spring as an ecosystem had been struck by rapidly changed of landuse. This research aims to analysethe vegetation composition and its physiological characters of dominant plant cover species in Geger spring’s WCA. WCA was constructed using Quickbird image, topographic and geohydrological map; and plant cover classification was delineated based on its image. Geger spring’s WCA is 9,875.3 ha size,20.0% of WCA is still coverred by dense plantation dominated by Swietenia mahagoni (IV=110.8 %), and more than 68%of area is dominated by teak and Gnetum gnemonplantations (IV=92.1%) represented medium plant cover class. The shrubs, herbaceous and grasses of floor vegetation are dominated with Chromolaenaodorata and Ageratum conyzoides, Piperomia pellucida and Oplismenus burmanii.Transpiration rate of dominant tree seedlings (3 months) from high to low are F. benjamina(> 2 yrs) , T. grandis, S.aqueum, I. fagiverus, and G. gnemon. Water suction by roots from high to low are T. grandis, I. fagiverus, F. benjamina, Syzygium sp. and G. gnemon respectively. Percentage of water infiltration of land covered by shrubs is 75.2% and covered by herbaceous and grasses is 77.6%.  Plant species selection for revegetation of spring WCA is very important in order to ensure water spring sustainability.

Keywords: Geger spring, WCA, plant composition, physiological character