Setting conservation priorities in cities: approaches,targets and planning units adapted to wetland biodiversity and ecosystem services

Context

Protecting wetlands in cities is challenging. A cost-effective spatial prioritization approach taking into account stakeholder motivations is needed to identify wetlands of conservation interest.

Objectives

This study aims to optimize the efficiency of a systematic conservation planning (SCP) approach to protect nine urban wetland ecosystem services (ES) and biodiversity.

Methods

First, we mapped ES supply and demand to capture their spatial variation as they occur at the wetland scale. Secondly, using wetland property value as cost data, we compared the efficiency of SCP to two multicriteria scoring approaches. Thirdly, we compared SCP alternatives by changing the planning unit scale and conservation objectives (i.e. emphasizing ES demand and focusing on the most important ES).

Results

The total cost of the scoring approach networks was minimally 13 times higher, when compared to the SCP approaches. Consequently, the scoring approaches were at least five times less efficient than SCP per unit of network area ($/m²). Decreasing the size of planning units resulted in further cost reduction, with networks that were up to 92% less costly. We also highlighted that beneficiary demand fulfillment in networks could be optimized without a loss in efficiency. Finally, SCP secured nine ES for the same expenditure as that required to protect four public safety related ES. However, planning solely for these four important ES failed to represent those of other ES.

Conclusions

Our results may provide a tool to better inform land use decision planning in order to mitigate the impacts of urban growth on ES.