• Journal of Ecology and Environment
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• v.47 no.3
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• pp.75-84
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• 2023

Background: Knowledge of the spatial trends of plant invasions in different habitats is essential for a better understanding of the process of these invasions. We examined the variation in invasive alien plant species (IAS) richness and composition at two spatial scales defined by elevation and habitat types (roadside, forest, and cultivated lands) in the Makawanpur district of Nepal. Following an elevation gradient ranging from 500 to 2,400 m asl along a mountain road, plant species cover was recorded within sample plots of size 10 m × 5 m. Systematic random sampling was adopted in every 100 m elevation intervals on three habitat types. Results: Altogether 18 invasive alien plants belonging to eight families were recorded within 60 plots, of which 14 species (representing 80%) were from tropical North and South America. The most common plants by their frequency were Ageratina adenophora, Chromolaena odorata, Bidens pilosa, Lantana camara, and Parthenium hysterophorus. We found a significant relationship between species composition and elevation in the study area. Low-elevation regions had a higher number of alien species as compared to high-elevation regions within different habitat types. Conclusions: The species richness and density of IAS were higher in the road site followed by the cultivated land and forest sites. This pattern occurred throughout the elevation range and habitats. IAS were found mostly in the open land with high sunlight availability. Information from such scientific assessment of invasive alien plants will assist in developing appropriate management plans in the Makawanpur district.

• Journal of Korean Society of Forest Science
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• v.103 no.1
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• pp.23-29
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• 2014

Open- to closed canopy stage and it's ecological characteristics in vegetation succession are commonly described, but poorly understood in Korea. Vegetation development on structure, environment and understory abundance were studied for 16 yr in post-clearcut Pinus densiflora forests in the southern Gangwon-do province by applying space-for-time approach. We sampled 210 plots (10 for structure and 200 for understory) for four seral stages (1yr, 3yr, 10yr and 16yr). After clear-cut, mean stem density increased gradually to $5,714{\pm}645$ stems/ha after 16 years and mean basal area was also from $5.5{\pm}0.7m^2/ha$ after 10 years and doubled at $10.0{\pm}1.6m^2/ha$ in 16 years. Woody debris and bared soil on the forest floor peaked at 11--- after 10 years and at 10.3--- after 3 years, respectively. In understory mean cover declined with all growth form groups following succession, but in richness, forb specie increased with structural development during 16 years. Our study suggested that overstory development did not suppressed whole understory properties especially in richness, thus appeared to act as a filter selectively constraining the understory characteristics. However only long-term studies are essential for elucidating patterns and processes that cannot be inferred form short-term or space-for-time researches. Strong negative relationship between overstory and understory characteristics in conventional models surely reexamined.