A process-based assessment of landscape change and salmon habitat losses in the Chehalis River basin, USA

Identifying necessary stream and watershed restoration actions requires quantifying natural potential habitat conditions to diagnose habitat change and evaluate restoration potential. We used three general methods of quantifying natural potential: historical maps and survey notes, contemporary reference sites, and models. Historical information was available only for the floodplain habitat analysis. We used contemporary reference sites to estimate natural potential habitat conditions for wood abundance, riparian shade, main channel length, and side channel length. For fine sediment, temperature, and beaver ponds we relied on models. We estimated a 90% loss of potential beaver pond area, 91% loss of side-channel length, and 92% loss or degradation of floodplain marshes and ponds. Spawning habitat area change due to wood loss ranged from -23% to -68% across subbasins. Other changes in habitat quantity or quality were smaller—either in magnitude or spatial extent—including rearing habitat areas, stream temperature, and accessible stream length. Historical floodplain habitat mapping provided the highest spatial resolution and certainty in locations and amounts of floodplain habitat lost or degraded, whereas use of the contemporary reference information provided less site specificity for wood abundance and side-channel length change. The models for fine sediment levels and beaver pond areas have the lowest reach-specific certainty, whereas the model of temperature change has higher certainty because it is based on a detailed riparian inventory. Despite uncertainties at the reach level, confidence in subbasin-level estimates of habitat change is moderate to high because accuracy increases as data are aggregated over multiple reaches. Our results show that the largest habitat losses were floodplain and beaver pond habitats, but use of these habitat change results in salmon life-cycle models can illustrate how the potential benefits of alternative habitat restoration actions varies among species with differing habitat preferences.

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Prioritization of Vulnerable Species Under Scenarios of Anthropogenic-Driven Change in Georgia's Coastal Plain

Journal of Fish and Wildlife Management ◽

10.3996/jfwm-20-089 ◽

2021 ◽

Author(s):

Elizabeth A. Paulukonis ◽

Brian A. Crawford ◽

John C. Maerz ◽

Seth J. Wenger ◽

Nate P. Nibbelink

Keyword(s):

Sea Level Rise ◽

Sea Level ◽

Urban Growth ◽

Coastal Plain ◽

Habitat Change ◽

Individual Species ◽

Distribution Models ◽

High Exposure ◽

Management Actions ◽

Potential Habitat

Abstract Effective management of wildlife populations benefits from an understanding of the long-term vulnerability of species to anthropogenic stressors. Exposure to potential habitat change is one measure of vulnerability that wildlife managers often use to assess and prioritize individual species or groups of species for resource allocation or direct management actions. We used species distribution models for 15 species occurring in the coastal plain ecoregion of Georgia to estimate the current amount and distribution of potential habitat and then predict exposure to changes in habitat due to inundation from sea level rise (using the Sea Level Affecting Marshes model) and urban growth (using the Slope Land-use Excluded Urban Topology Hillshade Growth model) for four future time points. Our results predict that all focal species were likely to experience some exposure to habitat change from either sea level rise or urbanization, but few species will experience high exposure to change from both stressors. Species that use salt marsh or beach habitats had the highest predicted exposure from sea level rise (25–69%), while species that use more inland habitats had the highest predicted exposure to urban growth (10–20%). Our models are a resource for managers considering tradeoffs between prioritization schemes under two future stressors. Results suggest that managers may need to prioritize species (or their habitats) based on the predicted magnitude of habitat loss, while also contextualizing prioritization with respect to the current amount of available protected habitat and species global vulnerability.

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Hierarchical climate-driven dynamics of the active channel length in temporary streams

Scientific Reports ◽

10.1038/s41598-021-00922-2 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Gianluca Botter ◽

Filippo Vingiani ◽

Alfonso Senatore ◽

Carrie Jensen ◽

Markus Weiler ◽

...

Keyword(s):

Temporal Variations ◽

Channel Length ◽

Mathematical Framework ◽

Stream Length ◽

Temporary Streams ◽

Temporary Stream ◽

Discontinuous Flow ◽

Hierarchical Structuring ◽

Average Fraction ◽

Active Channel

AbstractLooking across a landscape, river networks appear deceptively static. However, flowing streams expand and contract following ever-changing hydrological conditions of the surrounding environment. Despite the ecological and biogeochemical value of rivers with discontinuous flow, deciphering the temporary nature of streams and quantifying their extent remains challenging. Using a unique observational dataset spanning diverse geomorphoclimatic settings, we demonstrate the existence of a general hierarchical structuring of river network dynamics. Specifically, temporary stream activation follows a fixed and repeatable sequence, in which the least persistent sections activate only when the most persistent ones are already flowing. This hierarchical phenomenon not only facilitates monitoring activities, but enables the development of a general mathematical framework that elucidates how climate drives temporal variations in the active stream length. As the climate gets drier, the average fraction of the flowing network decreases while its relative variability increases. Our study provides a novel conceptual basis for characterizing temporary streams and quantifying their ecological and biogeochemical impacts.

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Determining the Reference Ephemeroptera Communities in the Eastern Part of the Black Sea Region for the Implementation of the Water Framework Directive in Turkey

Transylvanian Review of Systematical and Ecological Research ◽

10.1515/trser-2015-0058 ◽

2015 ◽

Vol 17 (1) ◽

pp. 177-194

Author(s):

Gencer Türkmen ◽

Nilgün Kazanci

Keyword(s):

Cluster Analysis ◽

Water Framework Directive ◽

Black Sea ◽

The Black Sea ◽

Habitat Conditions ◽

Reference Sites ◽

Black Sea Region ◽

Statistical Results

Abstract In this study, we aimed to determine the reference sites and their reference Ephemeroptera communities according to the Water Framework Directive methods in the Eastern Part of the Black Sea Region of Turkey between 2008-2011. From the area, twentyfour collecting sites were chosen. There were thirty Ephemeroptera species identified, belonging to seven families and eleven genres. Cluster analysis based on Bray-Curtis similarities was applied. Reference habitat conditions of the studied sites and their reference Ephemeroptera communities were determined by combining both ecological and statistical results. As a result, sixteen sites had reference habitat conditions and their reference Ephemeroptera species were identified.

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Climate change drives widespread shifts in lake thermal habitat

Nature Climate Change ◽

10.1038/s41558-021-01060-3 ◽

2021 ◽

Author(s):

Benjamin M. Kraemer ◽

Rachel M. Pilla ◽

R. Iestyn Woolway ◽

Orlane Anneville ◽

Syuhei Ban ◽

...

Keyword(s):

Life Histories ◽

Habitat Change ◽

Tropical Lakes ◽

Ecological Interactions ◽

Thermal Habitat ◽

Habitat Changes ◽

Potential Habitat ◽

Conservation Actions ◽

Time Periods

AbstractLake surfaces are warming worldwide, raising concerns about lake organism responses to thermal habitat changes. Species may cope with temperature increases by shifting their seasonality or their depth to track suitable thermal habitats, but these responses may be constrained by ecological interactions, life histories or limiting resources. Here we use 32 million temperature measurements from 139 lakes to quantify thermal habitat change (percentage of non-overlap) and assess how this change is exacerbated by potential habitat constraints. Long-term temperature change resulted in an average 6.2% non-overlap between thermal habitats in baseline (1978–1995) and recent (1996–2013) time periods, with non-overlap increasing to 19.4% on average when habitats were restricted by season and depth. Tropical lakes exhibited substantially higher thermal non-overlap compared with lakes at other latitudes. Lakes with high thermal habitat change coincided with those having numerous endemic species, suggesting that conservation actions should consider thermal habitat change to preserve lake biodiversity.

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Identifying the potential of anadromous salmonid habitat restoration with life cycle models

PLoS ONE ◽

10.1371/journal.pone.0256792 ◽

2021 ◽

Vol 16 (9) ◽

pp. e0256792

Author(s):

Jeffrey C. Jorgensen ◽

Colin Nicol ◽

Caleb Fogel ◽

Timothy J. Beechie

Keyword(s):

Life Cycle ◽

Chinook Salmon ◽

Habitat Restoration ◽

Coho Salmon ◽

Life Stage ◽

Fine Sediment ◽

Life Stages ◽

Beaver Pond ◽

Barrier Removal ◽

Life Cycle Models

An investigation into the causes of species decline should include examination of habitats important for multiple life stages. Integrating habitat impacts across life stages with life-cycle models (LCMs) can reveal habitat impairments inhibiting recovery and help guide restoration efforts. As part of the final elements of the Habitat Restoration Planning model (HARP; Beechie et al. this volume), we developed LCMs for four populations of three species of anadromous salmonids (Oncorhynchus kisutch, O. tshawytscha, and O. mykiss), and ran diagnostic scenarios to examine effects of barrier removal, fine sediment reduction, wood augmentation, riparian shade, restoration of the main channel and bank conditions, beaver pond restoration, and floodplain reconnection. In the wood scenario, spawner abundance for all populations increased moderately (29–48%). In the shade scenario, spring-run Chinook salmon abundance increased the most (48%) and fall-run Chinook salmon and steelhead were much less responsive. Coho responded strongly to the beaver pond and floodplain scenarios (76% and 54%, respectively). The fine sediment scenario most benefitted fall- and spring-run Chinook salmon (32–63%), whereas steelhead and coho were less responsive (11–21% increase). More observations are needed to understand high fine sediment and its impacts. Our LCMs were region-specific, identifying places where habitat actions had the highest potential effects. For example, the increase in spring-run Chinook salmon in the wood scenario was driven by the Cascade Mountains Ecological Region. And, although the overall response of coho salmon was small in the barrier removal scenario (6% increase at the scale of the entire basin), barrier removals had important sub-regional impacts. The HARP analysis revealed basin-wide and regional population-specific potential benefits by action types, and this habitat-based approach could be used to develop restoration strategies and guide population rebuilding. An important next step will be to ground-truth our findings with robust empirically-based estimates of life stage-specific survivals and abundances.

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