Long-term Mapping of Ecosystem Services at the Aquatic-Terrestrial Interface

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River-floodplains and riparian zones are highly productive, spatially heterogeneous ecosystems which maintain important environmental services such as wildlife habitat and water quality. Because of this heterogeneity, riparian systems are challenging to map and monitoring changes in the environmental services derived from riparian zones is challenging. High spatial resolution, long-term data are essential in this task. In the Gergel Landscape Ecology Lab at UBC, we are developing new techniques for analyzing the dynamics of river-floodplains at several contrasting spatio-temporal scales. To understand long-term changes and dynamics of recovery in river-floodplain systems, we have pioneered novel uses of historical aerial photography and continue to build upon this foundation in the current proposal. These techniques enable improved quantification of fine-scale spatial heterogeneity (beyond what can be captured with moderate resolution imagery such as Landsat). This proposal develops and critically evaluates methods for mapping multiple floodplain services over the long-term. Our research design emphasizes riparian and floodplain ecosystems due to their high productivity, long history of use, and importance in conservation and restoration.The proposed research uses a suite of mapping approaches to quantify environmental services over time, in order to understand the patterns and drivers of sustainable and unsustainable use. At the local level, changes in tree species and size are important to monitor; and at the landscape level, loss and fragmentation of riparian habitat patches are critical. We develop new techniques for quantifying historical ecosystem services (using historical air photos and land survey data). Specifically, we use historical aerial photography and adapt conventional forest inventory interpretation and modelling techniques to quantify ecosystem attributes such as large woody debris sources and riparian habitat features. This approach enables reconstruction of historical dynamics from 1930s to 1950s, representing landscape baseline conditions prior to changes caused by forest harvest and floodplain development. Also, we utilize historical land survey data (from the late 1800s) to reconstruct ecosystem services from the past century. We also examine fragmentation and connectivity variables important to watershed function (such as riparian buffer connectivity). We assess and compare the utility of new metrics (such as network analysis) for assessing river-floodplain connectivity, and develop ways to account for sources of error in connectivity measures. We contrast these approaches in interior vs. coastal river-floodplain systems, further testing the generality of our results and the universal applicability of these tools.These approaches represent a much longer view of the declines, recovery and changes in environmental services (ES) than previous ES mapping efforts. When used combination, they present an unparalleled view of the changes and tradeoffs made in past landscape management essential in improving future management. The proposed work will contribute to improved mapping ecosystem services, which can assist decision-making to better balance among the diverse ecosystem services expected from watershed landscapes.