77-2 台灣國有林自然保護區植群生態之調查研究─南澳闊葉樹保護區植群生態之研究

• 台灣國有林自然保護區植群生態之調查研究南澳闊葉樹保護區植群生態之研究

VEGETATION ECOLOGY OF NATURE RESERVE

IN TAIWAN NATIONAL FOREST

STUDIES ON THE VEGETATION ECOLOGY

OF NANAO HARDWOOD NAYURE RESERVE

蘇鴻傑

摘 要

南澳闊葉樹自然保護區屬於國有林和平事業區第87林班之部分林地，位於台灣東北部南澳南溪及和平溪之間的山脊附近，為澳花溪上游之集水區，當地海拔在1000至1500公尺之間，總面積約200公頃，集水區中央之神秘湖，為濕性演替之晚期，水深僅2公尺，水域面積約1.5公頃，若包括湖邊之濕性沼澤則約有4.8公頃。目前整個湖面已充滿水生植物，屬微齒眼子菜—金魚藻型沈水性植物，近岸淺水處有東亞黑三稜—水毛花型之挺水植物，湖畔則為柳葉若—水芹菜型之濕生草本社會及五節芒型之高草原，此一系列植物社會，代表濕性演替之先後階段。神秘湖上下游淤積河床上已有早期森林出現，分別為水社柳—赤楊林型及九芎—小葉茶梅林型，而山坡地之盛行植群則為錐果櫟—長尾柯林型，相當於台灣山地櫟林帶下層之常綠闊葉林（暖溫帶雨林）。此等林型之直徑級分析，顯示前二種林型將經由演替逐漸變為後一種極盛相森林，而林型之樹種歧異度統計亦符合此一趨勢。本保護區之植物保護重點，應屬神秘湖之水生植物及湖邊之水社柳森林，值得觀察之生態系變遷現象則為湖泊演替及沼澤植物與森林之消長，稀有之植物包括東亞黑三稜，微齒眼子菜、卵葉小丁香、小狸藻、小葉四葉葎及水社柳等。本研究除列舉保護區之植物目錄外，另建議設置永久樣區，以便長期觀察研究，文末並建議可行之保育管理措施，以供主管單位參考。

Summary

Nanao nature reserve is a small watershed located near a water divide in northeastern Taiwan. The whole watershed covers an area of about 200 ha., with elevations ranging from 1000 to 1500 meters. Lying in the valley is a small pond called Shenmihu (Mystery Lake) which represents the late stage of hydrosere. The water body measures only 2 meters deep and 1.5 ha. In size, although the marsh bordering the shore extends to an area of 4.8 ha.

Thesubmerged aquatic plant community known as Potamogeton maackianus-Ceratophyllum demersum type has flourished throughtout the whole water. Emergent plants growing on shallow water are recognized as Spaganium fallax-Schoenopletus mucronatus type. The marsh of Isachne globosa-Oenathe javanica type thrives best along the shore and upper valley, while the tall grassland of Miscanthus floridulus type occupies the elevated substrate. These seral stages are quite evident around the shore. In a few sites the elevated beds and marsh have been invaded by pioneer trees forming deciduous forests identified as Salix Kusanoi-Alnus formosana type and Lagerstroemia subcostata-Camellia transarisanensis type. The upland forest is represented by Cyclobalanopsis longinux-Castanopsis carlesii type corresponding to the evergreen broad-leaved forest (warm temperate rain forest) of lower Quercus zone in the mountain forest belts of Taiwan. The former two seral types would developed into the latter type of climax forest, as is evidenced from the population structures of trees. This is also sustained by the species diversity of these forest communities. This reserve highlights the sere of hydrarch succession. The principle focus of conservation is on the aquatic plants and seral trees which are of rare occurrence in Taiwan. Rare species evaluated include Spaganium fallax, Potamogeton maackianus, Utricularia minor, Ludwigia ovalis, Galium trifidum and Salix kusanoi. An inventory of all plants collected during the study has been prepared in addition to the analysis of vegetations. Permanent plots were established for later studies. Appropriate conservation managements have also been suggested.