How fern and fern allies respond to heterogeneous habitat

The Yuanjiang dry-hot valley features hot and dry climate, low vegetation
and soil degradation. It had lush vegetation in the past, but has become
degraded in recent decades. Understanding the interrelationship between
species and the habitat is necessary to explain this change. In this
study, a link between fern and fern allies - a group that is
hypersensitive to environmental factors and their circumstances is
constructed. Intensive transects and plots were designed to be proxies for
extant fern and fern allies, and their habitats. Fifty years of
meteorological records of precipitation and temperature along altitude and
river running direction (latitudinal) were employed. Alpha and beta
diversity are used to access diversity. Species_estimated, Singletons,
Uniques, ACE, ICE, and Chao2, which associate to abundance and rarity, are
subscribed to the correlation between fern and fern allies, and their
ecosystem. Eight species, Selaginella pseudopaleifera, Aleuritopteris
squamosa, Adiantum malesianum, Pteris vittata, Davallia trichomanoides,
Sinephropteris delavayi, Selaginella jugorum, and Lygodium japonicum are
used as indicators of a typical xeric and sun-drying habitat. The results
indicate (1) accompanied by dramatically shrinking habitats, fern and fern
allies are in very low diversity and abundance, whereas the rarity is
relatively high; (2) for fern and fern allies, environmental factors are
positive when altitude goes up; and (3) eight indicator species are
latitudinally correlated with fern and fern allies along the river running
direction.