Attacked from two fronts: Interactive effects of anthropogenic and biotic disturbances generate complex movement patterns

Figures & data

Figure 1. This study was conducted in the Udtja reindeer herding community, northern Sweden. © Lantmäteriet, Sametinget (www.sametinget.se/8744). ArcGIS World Imagery basemap source: Esri, DigitalGlobe, GeoEye, Earthstar Geographics, CNES/Airbus DS, USDA, USGS, AEX, Getmapping, Aerogrid, IGN, IGP, swisstopo, and the GIS user community

Figure 2. Differences in the daily average Euclidean distance (in kilometers) between reindeer locations and the points of military activity (y-axes) in the absence or presence of military exercises (x-axes) in the Vidsel test range, Sweden, from 1 August to 10 September, 2010–2012. The occurrence of military exercises is noted as follows: 0 = absence; 1 = exercises performed at one activity point; 2 = exercises performed at two activity points; 3 = exercises performed at three activity points. (a) Military exercises performed with terrestrial vehicles and (b) military exercises performed with aircraft

Table 1. Effects of military exercises, insect harassment, and environmental and anthropogenic predictor variables on reindeer movement rates

Model	Predictor	β	SE	p Value
OHI–Vehi_ALL	Intercept	44.12	63.57	.488
	OHI	−0.52	24.31	.983
	Distance from roads	−0.01	0.00	<.001***
	Elevation	0.15	0.11	.173
	Slope	−11.46	3.48	.001***
	NDVI	−0.01	0.00	.087*
	Outside	59.68	29.00	.040**
	OHI: elevation	0.10	0.05	.075*
	Distance from roads: Outside	−0.06	0.01	<.001***
OHI–Air_ALL	Intercept	37.76	64.32	.557
	OHI	2.79	24.50	.909
	Distance from roads	−0.02	0.00	<.001***
	Elevation	0.18	0.11	.119
	Slope	−11.46	3.49	.001***
	Air_ALL	−11.50	9.59	.230
	NDVI	−0.01	0.00	.086*
	Outside	57.28	29.26	.050**
	OHI: elevation	0.09	0.06	.100
	Distance from roads: Outside	−0.06	0.01	<.001***
	Air_ALL: Outside	25.12	15.86	.113
MHI–Vehi_ALL	Intercept	−20.54	59.32	.729
	MHI	81.50	11.13	<.001***
	Distance from roads	−0.02	0.00	<.001***
	Elevation	0.27	0.10	.005**
	Vehi_ALL	−22.45	12.69	.077*
	Slope	−11.25	3.48	.001***
	NDVI	−0.01	0.00	.113
	Outside	54.08	29.53	.067*
	Vehi_ALL: MHI	29.96	14.72	.042**
	Distance from roads: Outside	−0.06	0.01	<.001***
	Vehi_ALL: Outside	23.84	14.83	.108
MHI–Air_ALL	Intercept	−19.51	59.32	.742
	MHI	79.71	10.98	<.001***
	Distance from roads	−0.02	0.00	<.001***
	Elevation	0.27	0.10	.004**
	Air_ALL	−29.61	12.27	.016**
	Slope	−11.26	3.48	.001***
	NDVI	−0.01	0.00	.104
	Outside	54.24	29.49	.066*
	Air_ALL: MHI	39.24	14.41	.007**
	Distance from roads: Outside	−0.06	0.01	<.001***
	Air_ALL: Outside	31.24	15.81	.048**

Note: Results refer to reduced regression models obtained with an automatic model selection procedure starting from the best-fit generalized least squares models listed in Online Resource, Table S4. All models included a variance structure fixed by year and an exponential spatial autocorrelation structure applied to the model residuals (range = 850, nugget = 0.4, sill = 1). Vehi_ALL and Air_ALL are continuous variables indicating the occurrence of military exercises performed at zero, one, two, or three military activity points, with either terrestrial vehicles or aircraft. Distance from roads = Euclidean distance in meters from the closest road. Outside = category of the dummy variable area, indicating that a reindeer was outside the military test range (reference category: inside). Statistically significant variables (p ≤ .05) are highlighted in bold.

***p ≤ .001. **< p ≤ .0.05. *p ≤ 0.10.