Spatial pattern of plant diversity in a group of uninhabited islands from the perspectives of island and site scales

Uninhabited islands are important for providing isolated habitats for unique biological resources, and revealing
the spatial pattern of plant diversity is of great significance for the island biodiversity conservation. A total of
15 uninhabited islands in Miaodao Archipelago, a group of typical uninhabited islands in North China, were selected
as the study area. The multiple gradients at island and site scales were identified and quantified based
on field investigation and remote sensingmethods, and seven “frommacro tomicro” aspects, includingmorphology,
proximity, landscape, terrain, atmosphere, soil, and vegetation, were selected to cover all aspects of factors
influencing the plant diversity. Then, the single and comprehensive effects of themultiple gradients on the spatial
pattern of plant diversity at the dual scales were analyzed using methods of regression analysis and canonical
correspondence analysis ordination. Results indicated that 130 plant specieswere recorded. The species accumulation
curves proved the sufficiency of the numbers of sampling sites and islands to represent the overall characteristics
of plant diversity. The species composition on the uninhabited islands possessed common characteristics
with the neighboring inhabited islands and mainland, meanwhile, showed unique features on the dominant
species. The α diversity showed distinct spatial heterogeneities at the dual scales; the β diversity indicated the
great difference of species composition within an island and among different islands. At island scale, island
area, vegetation condition, and terrain complexity contributed the most to the spatial pattern of plant diversity.
At site scale, biodiversity indices changed irregularly along the multiple gradient factors, yet all aspects of
gradients showed significant effects on the species composition and distribution. The island area played a
fundamental role in determining the α diversity at island scale and generating the β diversity within an island,
however, was not significantly correlated with the diversity at site scale.
Publication Name: 
Science of The Total Environment
Page Number: 
Chi, Yuan; Sun, Jingkuan; Fu, Zhanyong; Xie, Zuolun