Landscape Ecology and Population Dynamics Brood parasitism rates 491 Population growth Expected population growth rate Parasitism rate 0⋅0−0.2 Low 0⋅2−0.4 Moderate 0⋅4−0.8 High < 0⋅90 Strong sink 0⋅90−1⋅00 Weak sink 1⋅00−1⋅10 Weak source No song sparrows N 012 (a) N 012 (km) (b) (km) Figure Maps of brood parasitism and population growth of song sparrows (Melospiza melodia) in the Southern Gulf Islands of British Columbia, Canada Rates of parasitism by brown-headed cowbirds (Molothrus ater) (a) are affected by land use and results in variation in population growth rates of their sparrow hosts (b) Growth rates are expressed in terms of finite rates of increase Rates Z1 indicate stable or growing populations (sources), whereas rates o1 represent declining or sink populations Reprinted from Jewell KJ and Arcese P (2008) Consequences of parasite invasion and land use on the spatial dynamics of host populations Journal of Applied Ecology 45: 1180–1188, with permission from Wiley Wildebeest (1000s) 1600 1° S Lake Victoria 1200 Wildebeest dry season Nairobi Musoma 800 Kenya 400 Tanzania 0 20 40 60 Time (yr) Total population (no road) Total population (road) 80 Wildebeest wet season 3° S 100 Northern subpopulation (road) Southern subpopulation (road) Arusha 33° E Migration route Proposed road Figure Potential impact of a proposed road on Serengeti wildebeest populations (a) Results of spatially explicit simulation model on abundance of wildebeest (Connochaetes spp.) comparing the landscapes with (red line) and without (black line) proposed road The road would separate wildebeest into northern and southern populations shown by blue and green lines Graph reprinted from Holdo RM, Fryxell JM, Sinclair ARE, Dobson A, and Holt RD (2011) Predicted impact of barriers to migration on the Serengeti wildebeest population Public Library of Science One 6: 1–7 Map provided by Stuart Pimm, with permission from PLOS Although the overall abundance of required resources is of great importance for populations, the patchiness and spatial arrangement of habitat types have the potential to complicate population dynamics in landscapes Demographic rates, such as survival and reproduction, may be affected by patch size and shape Movements between patches can be influenced by the distance between patches and other spatial features Therefore, an understanding of how population dynamics play out in space is important for research and management