Effect of Gap Light Factors on Understory Plant Species Distribution in Urban Scenic Forests of Guangzhou

The relationships between gap light factors and understory plant species were investigated based on field survey data collected from three sample plots in urban scenic forests of Guangzhou,with a total area of 3 hm2.Multi-response permutation procedures(MRPP) revealed that understory plant species were significantly influenced(P0.01) by four gap light factors,i.e.,canopy openness,understory direct radiation,understory diffuse radiation and understory total radiation.Indicator species analysis(ISA) detected 15 species for canopy openness,9 species for understory total radiation,and 5 species for understory direct radiation and understory diffuse radiation,respectively.Canonical correspondence analysis(CCA) also showed that canopy openness,understory direct radiation,understory diffuse radiation,as well as understory total radiation,had significant effects on understory plant species.Findings from this study have implications for future research on patterns of understory plant species in response to gap light factors.