Geology topics

Sara Cendejas-Zarelli

Publications and source records attributed to Sara Cendejas-Zarelli.

3 recordsLinked to original sources

USGS2024

Establishment of terrestrial mammals on former reservoir beds following large dam removal on the Elwha River, Washington, USA

Terrestrial wildlife species are important yet often overlooked taxa in the recovery of ecosystems following dam removal. Their presence can shape ecosystem recovery, signal restoration of ecosystem function, and influence food web dynamics and nutrient transfer. We used camera traps to examine seasonal use of two former reservoir beds and an upstream reference reach by the mammalian community following the removal of two large dams on the Elwha River, Washington, USA. For certain taxa, we compared current species use to data collected prior to dam removal. Camera traps revealed use by at least fifteen mammal species, including but not limited to American black bear ( Ursus americanus ), Columbian black-tailed deer ( Odocoileus hemionus columbianus ), Roosevelt elk ( Cervus elaphus roosevelti ), puma ( Puma concolor ), coyotes ( Canis latrans ), bobcats ( Lynx rufus ), and snowshoe hares ( Lepus americanus ). Coyotes were found mostly lower in the watershed outside the Olympic National Park boundary, while other species were distributed throughout the restoration area. We did not see major differences in species composition between the restoration areas and the upstream reference reach, though number of detections across study reaches differed for most species. Unlike previous findings, black bears were observed across all seasons in this study, suggesting a shift in seasonal use since dam removal. Full restoration of the terrestrial wildlife community could take decades to unfold, but early patterns demonstrate rapid establishment and use by wildlife on new riparian surfaces that are expected to continue to evolve with restoration of fish and vegetation communities.

Washingotn↗

USGS2023

A review of natural and managed revegetation responses in two de-watered reservoirs after large dam removals on the Elwha River, Washington, USA

Large dam removals are increasing in frequency and the response of natural and managed revegetation is a critical consideration for managed restoration of dewatered reservoir landscapes post dam removal. The removal of two large dams on the Elwha River in 2011-2014 provides insight into reservoir revegetation. We review literature and datasets from 2012 through 2018, 1-6 years since reservoir dewatering, to compare pre-dam removal predictions on the Elwha to post-dam removal of natural revegetation, managed revegetation effects and invasive non-native vegetation response. Pre-dam removal hypotheses about natural revegetation did not predict species performance on reservoir sediments, seed rain patterns, or seed bank response. Sediment texture and landform affected multiple aspects of revegetation, including vegetation cover, species richness, woody stem densities and species composition. Reservoir drawdown timing influenced species composition and seedling densities. Predictions about managed revegetation effects were mixed. Planting trees and shrubs did not accelerate woody cover but did increase species richness. Seeding reduced non-native vegetation frequency and species richness, had no effect on vegetation cover on fine sediments, but increased vegetation cover on coarse sediments. Planting trees and shrubs during drawdown appeared to result in higher survival rates compared to plantings installed 1+ years post drawdown. Seeding Lupinus rivularis (riverbank lupine) on coarse sediments was successful and increased foliar nitrogen in planted conifers. Invasive non-native vegetation was correctly predicted to be more abundant in the Aldwell reservoir but did not preclude native species establishment in either reservoir, likely due to rapid establishment of native species and robust management that occurred before, during and after dam removal.

Washington↗

USGS2020

Small mammals and ungulates respond to and interact with revegetation processes following dam removal

Terrestrial wildlife communities are often overlooked as components of ecosystem restoration following dam removal. However, a diverse mammalian fauna colonizes habitat on dewatered reservoirs and may influence restoration processes. We studied mammalian colonization and ungulate herbivory from 2014 to 2018 following the removal of two large dams on the Elwha River in Washington, USA. Specifically, we examined (1) small mammal colonization and (2) Roosevelt elk ( Cervus elaphus roosevelti ) and Columbian black-tailed deer ( Odocoileus hemionus columbianus ) distribution and browsing pressure in association with revegetation efforts. We live-trapped small mammals on two former reservoir beds and monitored deer and elk use by conducting pellet group counts and quantifying ungulate herbivory at plots throughout the former reservoir beds and an adjacent reference site. We found that the proportion of deciduous riparian species on plots best predicted occupancy for mice, shrews, and voles. Small mammal species diversity was best explained by the proportion of logs and conifers on study plots. Roosevelt elk presence and browsing intensity on willows ( Salix spp.) and black cottonwood ( Populus balsamifera ssp. trichocarpa ) varied both spatially and temporally, affecting the stature and potentially the growth trajectories of these species. Early seral restoration of these terrestrial habitats has included the presence of a diversity of granivores, insectivores, and herbivores, with elk demonstrating the strongest influence over portions of the study area. Small mammal colonization complements revegetation succession and demonstrates restoration of ecological processes, while large ungulates may be playing a more substantial role in shaping revegetation.

Washington↗