Present address: Australian Research Council Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, Qld 4811, Australia.
Irreplaceability of river networks: towards catchment-based conservation planning
Article first published online: 14 JUL 2008
© 2008 The Authors. Journal compilation © 2008 British Ecological Society
Journal of Applied Ecology
Volume 45, Issue 5, pages 1486–1495, October 2008
How to Cite
Linke, S., Norris, R. H. and Pressey, R. L. (2008), Irreplaceability of river networks: towards catchment-based conservation planning. Journal of Applied Ecology, 45: 1486–1495. doi: 10.1111/j.1365-2664.2008.01520.x
- Issue published online: 29 AUG 2008
- Article first published online: 14 JUL 2008
- Received 5 November 2007; accepted 3 June 2008; Handling Editor: John Richardson
- freshwater conservation;
- systematic conservation planning
- 1This study has adapted a complementarity-based area-selection method to estimate conservation value/irreplaceability for river systems. Irreplaceability represents the likelihood that an area will be required as part of a conservation system that achieves all conservation targets. We adapt this measure – often used in marine or terrestrial planning – to consider whole-of-catchment protection in a riverine setting.
- 2After dividing the Australian state of Victoria into 1854 subcatchments, we successfully modelled distributions of 400 benthic macroinvertebrate taxa using generalized additive models. We calculated the minimum area required to protect all taxa using three different heuristic selection algorithms. The algorithms were modified to consider the entire upstream catchment for any subcatchment.
- 3A summed rarity algorithm, corrected for upstream area, proved to be the most efficient, requiring 100 000 hectares less total catchment area to represent all taxa than the second most efficient algorithm. We calculated irreplaceability by running the algorithm 1000 times and randomly removing 90% of the catchments in each run. From this analysis, we estimated two metrics: Fs (the frequency of selection) and average c (average contribution to conservation targets).
- 4Four groups of catchments were identified: (i) catchments that have high contributions and are always or very frequently selected; (ii) catchments that have high contributions and are infrequently selected; (iii) catchments that are always or very frequently selected but contribute few taxa; and (iv) catchments that are infrequently selected and contribute few taxa.
- 5Synthesis and applications. For the first time, a complementarity-based algorithm has been adapted to a riverine setting. This algorithm acknowledges the connected nature of rivers by considering not only the local assemblages, but also upstream areas that need to be protected. We demonstrated that using standard algorithms in these connected systems would lead to two mistakes, namely: (i) not all taxa would be covered by reserves that were buffered from potential human disturbances upstream; and (ii) the standard algorithms would not lead to the most efficient solution, potentially costing additional millions of dollars to any conservation scheme. We therefore recommend the use of our algorithm or a similar riverine adaptation of reserve design algorithms to ensure adequate and efficient conservation planning.