Across Northern California’s Mattole River watershed, decades of logging, road construction, land clearing, fire suppression, and heavy sedimentation altered both upland prairies and coastal aquatic ecosystems. On Prosper Ridge, encroaching Douglas fir trees gradually spread into historic coastal grasslands, crowding out native perennial bunchgrasses and altering local water movement across the ridge. Downstream in the Mattole River Estuary, severe soil erosion from major historical floods filled deep river channels with fine sediment. This left the estuarine waterway shallow, unshaded, and dangerously warm for native migratory fish species seeking cold water refuge during critical rearing stages.
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