Biodiversity and Abundance of Angiosperms Responding to Resilience
Environments in the tidal range of Yuanjiang Dry-Hot Valley
Abstract
Yuanjiang dry-hot valley is poorly vegetated as a fragile arid
ecosystem. Although it was lushly forested in the past, it becomes a
tropical montane savannah in recent decades. This study focuses on the
relationship between plants and their living environments in the low
land of this dry-hot valley. Plant species and their individuals are
investigated in transects and plots arranging along the river channel.
Alpha and beta indices are employed to cope with biodiversity change in
species and environments. Estimated species, rarity and abundance
indices are subscribed to the correlation among species, population
size, and their living circumstances in terms of Species_estimated,
Singletons, Uniques, ACE, ICE, and Chao2. Meanwhile, fifty years’
meteorological records including temperature and precipitation are
collected for environmental references. The results indicate that: (1)
in Yuanjiang dry-hot valley, alpha diversity is higher in the transects
and plots closing to river channel than apart from while beta diversity
increases from upper stream to the lower with Bray-Curtis <
0.500, but this condition is reversed in the transect perpendicular to
the river; (2) tidal range contributes a lot in alpha biodiversity
especially in the upper stream; (3) estimated species, rarity and
abundance indices are significant in the sites closing to the river,
which is strongly indicating heterogeneous habitats. (4) Solanum
virginianum Ortega are screened as an indicator representing xeric
environment in Yuanjiang dry-hot valley. Conclusively, plants are not
flourished at the low altitude ascribed to high temperature and low
water supply. More attention and ecology policy should be thrived
exclusively to the microhabitat protection and environment management in
this valley.