Size-dependent resistance of protected areas to land-use change

Abstract

One of the major threats facing protected areas (PAs) is land-use change and habitat loss. We assessed the impact of land-use change on PAs. The majority of parks have been effective at protecting the ecosystems within their borders, even in areas with significant land-use pressures. More in particular, the capacity of PAs to slow down habitat degradation and to favour habitat restoration is clearly related to their size, with smaller areas that on average follow the dominant land-use change pattern into which they are embedded. Our results suggest that small parks are not going to be viable in the long term if they are considered as islands surrounded by a 'human-dominated ocean'. However, small PAs are, in many cases, the only option available, implying that we need to devote much more attention to the non-protected matrix in which PAs must survive.

Figure 1

Spearman rank correlations measured between mean land-use/land-cover change and PA size, and between mean land-use/land-cover change and the buffer size. Only the r value with the median q-value is shown. The correlation was measured across three different cell sizes and nine different size-class legends (table A1 in the electronic supplementary materials). Diamonds, dashed line, PAs (r=−0.850; q=0.0283) and crosses, solid line, buffer (r=−0.200; q=0.5493).

Figure 2

Spearman rank correlations measured between mean land-use/land-cover change and PA size, and between mean land-use/land-cover change and the buffer size towards (a) natural classes and (b) artificial classes. Only the r value with the median q-value is shown. The correlation was measured across three different cell sizes and three different size-class legends (table A2 in the electronic supplementary materials). (a) Diamonds, dashed lines, PAs (r=0.583; q=0.1815) and crosses, solid line, buffer (r=0.464; q=0.2641). (b) Diamonds, dashed line, PAs (r=−0.690; q=0.1385) and crosses, solid line buffer (r=−0.429; q=0.2843).

Figure 3

Spearman rank correlations measured between PA size and percentage of PAs with a mean change towards natural land-use/land-cover class which is greater than the respective buffer, and between PA size and percentage of PAs with a mean change towards artificial land-use/land-cover class which is greater than the respective buffer. Only the r value with the median q-value is shown. The correlation was measured across three different cell sizes and nine different size-class legends (table A3 in the electronic supplementary materials). Diamonds, dashed line, natural (r=0.905; q=0.0019) and crosses, solid line, artificial (r=−0.600; q=0.0292).