Dynamics of range margins for metapopulations under climate change

Abstract

We link spatially explicit climate change predictions to a dynamic metapopulation model. Predictions of species' responses to climate change, incorporating metapopulation dynamics and elements of dispersal, allow us to explore the range margin dynamics for two lagomorphs of conservation concern. Although the lagomorphs have very different distribution patterns, shifts at the edge of the range were more pronounced than shifts in the overall metapopulation. For Romerolagus diazi (volcano rabbit), the lower elevation range limit shifted upslope by approximately 700 m. This reduced the area occupied by the metapopulation, as the mountain peak currently lacks suitable vegetation. For Lepus timidus (European mountain hare), we modelled the British metapopulation. Increasing the dispersive estimate caused the metapopulation to shift faster on the northern range margin (leading edge). By contrast, it caused the metapopulation to respond to climate change slower, rather than faster, on the southern range margin (trailing edge). The differential responses of the leading and trailing range margins and the relative sensitivity of range limits to climate change compared with that of the metapopulation centroid have important implications for where conservation monitoring should be targeted. Our study demonstrates the importance and possibility of moving from simple bioclimatic envelope models to second-generation models that incorporate both dynamic climate change and metapopulation dynamics.

Figure 1

Predicted status of the R. diazi metapopulation: (a) female abundance, (b) number of occupied patches and (c) cumulative probability of decline to fewer than 1000 females. For each diagnostic, two scenarios are presented: dynamic climate change (black line) and a static climate (grey line). Error bars, based on 10 000 stochastic model iterations, are presented for every 10th year only with the two scenarios offset by 1 year for clarity.

Figure 2

Predicted status of the L. timidus metapopulation within Great Britain: (a) female abundance, (b) number of occupied patches and (c) cumulative probability of declining to less than 10% of the initial abundance. For each diagnostic, two scenarios are presented: dynamic climate change (black line) and a static climate (grey line). Error bars, based on 10 000 stochastic model iterations, are presented for every 10th year only with the two scenarios offset by 1 year for clarity.

Figure 3

Predicted changes for the R. diazi metapopulation in: (a) total area (solid lines) and core area (dashed lines) of all occupied patches; and (b) mean (dashed lines) and minimum (solid lines) elevation. Two scenarios are shown: the dynamic climate change scenario (black) and the stable climate scenario (grey). Isolated points (his) represent an estimate of the historical area and elevation, respectively.

Figure 4

Predicted shifts in latitude for L. timidus under three different dispersal scenarios: (a–c) low, (d–f) medium and (g–i) high. Trends are shown for: (a, d, g) the northern range limit (weighted mean latitude of the northern 10% of the population); (b, e, h) the core centroid of the population (weighted mean latitude of whole population); (c, f, i) the southern range limit (weighted mean latitude of the southern 10% of the population). For each range margin and the population as a whole, two scenarios are presented: dynamic climate change (black line) and a static climate (grey line). Values represent deviations from initial values. Dot-dashed line represents 2010 values.