Functional trait and community phylogenetic analyses reveal environmental filtering as the major determinant of assembly of tropical forest tree communities in the Western Ghats biodiversity hotspot in India

Forest Ecosystems

Table 3 The results of the t-tests between NRI values and forest types and levels of disturbance

Variable	Comparison	Mean	t	DF	P value	Clustered (%)	Overdispersed (%)
Forest type	EVG/MD	−0.017	3.177	74	0.002	17	6.5
	MD/DD	0.619	2.81	38	0.007	25	0
	DD/EVG	0.141	5.671	74	0.0001	55	0
Level of Human disturbance	None/low	−0.373	8.238	63	0.0001	2.3	14
	Low/high	0.823	1.097	52	0.278	12	0
	High/none	1.001	9.326	71	0.0001	58	0

Percentage values are the proportion of sites that were significantly clustered and overdispersed assemblages per category. Bold numbers represent the statistically significant results. DF degrees of freedom; EVG evergreen; DEC deciduous; MD moist deciduous; DD dry deciduous. The formula for t-test used is \( t=\left(\overline{x_1}-\overline{x_2}\right)/\sqrt{\left(\left({N}_1-1\right){s_1}^2+\left({N}_2-1\right){s_2}^2/{N}_1+{N}_2-2\right)\left(1/{N}_1+1/{N}_2\right)} \), where x̅₁ and x̅₂ represent means of two different forest types or disturbance level; N₁ and N₂ are sample size and s₁² and s₂²are an estimator of the common variance of the two samples
Significant results are indicated in bold