Table 1.
Landscape variables.
Fig 1.
U.S. distribution of (a) existing dams listed in the National Anthropogenic Barrier Dataset (n = 50,772); (b) removed dams from the Dam Removal Inventory Project (n = 874); (c) removed dams with before-after studies (n = 63).
Fig 2.
EPA Level III Ecoregions for existing and removed dams in the U.S., and before-after-removal studies.
Fig 3.
Comparison of (a) stream order; (b) watershed area (km2); (c) watershed slope (degrees); and (d) habitat condition index (risk of degradation) for existing (n = 50,772) and removed dams (n = 874), and dam removals with before- and after-removal studies (n = 63).
Fig 4.
Spatial distribution of landscape characteristics.
Spatial distribution of landscape characteristics for all removed dams: (a) upstream watershed elevation (m), (b) upstream watershed area (km2), (c) upstream watershed slope (degrees), and (d) habitat condition index (risk of habitat degradation).
Fig 5.
Principal Components Analysis results.
Principal Components Analysis results for (a) all dam removals (57 clusters); (b) all studied dam removals (36 clusters); and (c) before-after studied dam removals (32 clusters). The number of clusters in (a) was determined from a cluster analysis; clusters in (b) and (c) show how many original clusters were represented in those subsets.
Fig 6.
Spatial distribution of landscape clusters.
(a) Spatial distribution of clusters based on landscape characteristics for all dam removals. Upper Midwest and Northeast sections magnified to show details. (b) Spatial distribution of clusters based on landscape characteristics of before-after studied dam removals.
Table 2.
Principal component loadings.
Table 3.
Landscape clusters for before and after-removal studies.
Fig 7.
Before- and after-removal biophysical study parameters.
Number of dam removals with upstream, reservoir, and downstream studies that reported the before- and after-removal responses of physical, water quality, and biological parameters.
Table 4.
Reported biophysical metrics.
Table 5.
Measurement metrics.
Fig 8.
Biophysical responses to dam removal.
Biophysical response for all before- and after-removal studies (top row) and within each distinct geographic cluster.
Table 6.
Anthropogenic landscape context.