Ap. Ogrady et al., THE ABUNDANCE AND GROWTH OF AVICENNIA-MARINA AND RHIZOPHORA-STYLOSA IN THE LOW SHORE ZONE OF DARWIN HARBOR, NORTHERN-TERRITORY, Australian journal of ecology, 21(3), 1996, pp. 272-279
The growth and distribution of the two mangrove seedling species, Avic
ennia marina (Forsk.) Vierh, and Rhizophora stylosa Griff., were studi
ed in the low-shore zone at three locations along two estuaries of Dar
win Harbour to determine how growth varied along the estuary and withi
n the habitats of the low shore zone. The low shore environment was he
terogenous for factors such as salinity and light, with substantial va
riation within and between locations. Seedlings of Avicennia were in h
igher densities in light gaps than in the adjacent forest, and density
in both habitats decreased towards the mouth of the estuary. Growth o
f Avicennia seedlings, as measured through in situ growth trials and p
lant harvests, increased towards the mouth of the estuary. Results for
Rhizophora seedlings were more complex although some similar trends w
ere evident. This may have been due to the greater early survival of R
hizophora seedlings compared to Avicennia seedlings. The importance of
propagule origin was investigated, for Rhizophora, by transplanting p
ropagules between locations along one estuary. Increased seedling surv
ival was observed at the propagule source site; however, this effect w
as subtle and probably not the most important factor affecting seedlin
g survival at a site.