Management factors affecting densities of common grassland birds of high elevation grasslands of eastern South Africa: Ingula as a case study

Table 2 Summary of model selection analysis (see Additional file 2: Appendix S2 for full details) used to estimate the density of eight common grassland bird species at Ingula in relation to grazing, burning, grass height and grass cover

	Density models	CLC	WSC	AP	AQF	YBP	RCL	ZC	CQ
1.	dens(.)	2.72	18.36	26.61	15.93	24.24	8.81	22.78	8.03
2.	dens(Burning)	2.20	0.00	28.40	11.87	0.00	5.86	24.08	7.12
3.	dens(Grazing)	0.34	19.34	30.46	13.56	24.26	6.38	18.26	8.29
4.	dens(cover)	0.11	20.13	24.86	6.03	26.23	8.25	0.00	8.09
5.	dens(avh)	0.00	20.27	11.93	17.83	16.84	5.58	43.39	7.05
6.	dens(avh + cover)	0.55	22.09	0.00	0.00	16.55	0.00	12.60	8.29
7.	dens(s(cover))	1.71	8.24	30.53	4.82	23.17	21.58	24.94	0.00
8.	dens(s(avh))	0.73	3.59	21.01	35.61	22.31	20.08	3.93	6.95

For each species the detection function was modeled as in the best model in Table 1. The relationship between density and grass height and cover was modeled as linear (on the log scale) relationships (avh and cover) and using regression splines with two knots [s(avh) and s(cover)]. See notes to Table 1 for more detail

ISSN: 2053-7166