Protected area (PA) networks remain one of the most effective ways to connect habitats over large scales. Recent research has explored many ideas about how best design PA networks, from rules of thumb for creating marine protected areas, to global comparisons of network connectivity, to comparing the strategies and costs of network expansion.
Given that climate change is likely to cause many species to shift ranges, south-north connectivity is particularly important for keeping PAs relevant. Without the ability to move between protected areas, vulnerable species, especially habitat specialists, are likely to be left behind. This idea of climate-wise connectivity is being explored by new research that adds to the conservation decision-making process.
Travers, T.J., Alison, J., Taylor, S.D., Crick, H.Q. and Hodgson, J.A. 2021. Habitat patches providing south–north connectivity are under-protected in a fragmented landscape. Proceedings of the Royal Society B 288(1957): 20211010.
Protected areas of the world. (Credit: IUCN WCPA)
To better quantify south-north connectivity for PAs, a recent study focused on 16 conservation PA networks across England. The goal was three-fold: 1) to identify the extent that England’s current PA system supports connectivity; 2) to compare patch connectivity with patch area; and 3) to determine how conserving additional connected patches would improve overall network connectivity.
Priority habitat patches were assigned a “flow” value (using the decision-support software Condatis) based on general species dispersal, with a high flow designation representing a likely route for range expansion. This flow status was then compared to patch area, and used to evaluate each patch’s potential contribution to overall network north-south connectivity.
One of the most surprising results of the analysis is that although existing PAs were biased toward large habitat patches, they were also biased toward low-flow patches. This means that, in general, area is better protected than connectivity, and that small patches can disproportionately contribute to connectivity (for example, as stepping stones). As climate change pushes species poleward, past decisions that focused solely on conserving large patches for PAs seem to have left many species climate vulnerable.
The analysis also shows that a small addition of area to PA networks can lead to a big boost in connectivity. In England, a 10% increase in area of PAs could protect an average of 40% more connectivity. The decision-making tools used for the analysis can help conservation planning create better connected, more effective PA networks that allow species to track changing climate and shift when needed.
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