DYNAMICS OF KEKILLA FERNLANDS AND ABANDONED CHENA UNDER PARTIAL SHADE
AND FULL SUN CONDITIONS
M C Devendra and B M P Singhakumara
University of Sri Jayewardenepura, Nugegoda
Seed bank dynamics can be considered an important component of the regeneration
of individual plant populations and communities. Soil seed bank dynamics
in Kekilla fernlands and abandoned chena need to be studied as possible
sources of regeneration for forest restoration of degraded lands.
This study was done to understand regeneration dynamics of soil seed banks
with reference to two light regimes in Kekilla fernlands and abandoned
chena in the periphery of Sinharaja World Heritage Site.
Sinharaja World Heritage Site is one of the least disturbed and biologically
unique lowland rain forests now remaining in Sri Lanka. Today some areas
of the periphery of Sinharaja are covered with secondary scrub and Kekilla
(Dicranopteris linearis) fernlands. Three sites of Kekilla fernlands and
three sites of abandoned chena were selected for the study.
Four soil samples were purposively collected from four different locations
in each site. These four samples were pooled and mixed in a polythene
bag. Eight trays were prepared using one mixture of soil from one site.
Four trays from each site were placed under partial shade (750µ mol m-2
s-1 ) and others were placed under full sunlight (2000µ mol m-2 s-1 ).
Seeds inside the soils were allowed to germinate. Newly germinated seeds
were recorded every fifth day. All germinated seeds that were able to
be identified were removed and counted once a month.
Seedlings of 45 taxa were identified during the period of study. Among
the counted seedlings a larger proportion was recruited under the partial
shade treatment than full sun treatment. Results indicate that the number
of species germinated from abandoned chena was greater than that of Kekilla
fernlands. Finding suggest that in all treatments only pioneer species
germinated. Climax species were not represented in any of the sites or
Department of Forestry and Environmental Science,
of Sri Jayewardenepura,Sri Lanka. 1999. All rights reserved.