Associations between riverine landscape patches and internal and external environmental determinants are scale dependent: evidence from the Scioto River, USA
Tagwireyi, Paradzayi; Sullivan, S. Mažeika P.; Zhao, Kaiguang
published: Aug 1, 2017
published online: Jun 21, 2017
manuscript accepted: May 8, 2017
manuscript received: Feb 13, 2017
ArtNo. ESP141019003006, Price: 29.00 €
Abstract Associations between riverine landscapes – the integrated ecological unit including the riverscape and the floodplain – and their surrounding catchment landscapes remain largely unresolved. In an exploratory study, we investigated relationships between site-specific riverine landscape patterns and catchment land use and land cover (LULC) at twelve reaches distributed along an urban-to-rural gradient of the Scioto River, Ohio, USA. We calculated patch metrics (area, edge, diversity, shape, and density) for each riverine landscape and measured LULC (% agriculture, forest, open water, and urban) of the catchment landscape at three nested spatial extents (1,000, 3,000, and 6,000 m). To consider potential internal drivers of riverine landscape patchiness, we estimated drainage area (as a proxy for river size) and proximity to the nearest impoundment (as a proxy for flow heterogeneity). Drainage area and proximity to impoundment were strong predictors of patch shape (R2 = 0.46, negative relationship) and patch area (R2 = 0.67, positive relationship), respectively. However, evidence was almost equally as strong for catchment LULC predictors of both of these patch metrics at the 1,000 and 3,000-m extents: forest coverage for patch size, urban and agriculture coverage for patch area. Higher patch diversity was related to greater catchment forest coverage at 3,000 and 6,000-m extents. Our observations implicate both external (LULC characteristics) and internal (flow dynamics) controls as potentially important environmental determinants of riverine landscape patchiness. Our results suggest that management and conservation of the Scioto River basin, and potentially other river systems, should integrate both aquatic and terrestrial factors not just at one scale, but rather across a range of spatial extents.