Effects of Riparian Timber Harvest on Southeast Alaska Stream Habitat after 30–40 Years: Insights for Management

2019 ◽  
Vol 39 (2) ◽  
pp. 328-342 ◽  
Author(s):  
Jared A. Ross ◽  
Dana M. Infante ◽  
Douglas J. Martin ◽  
Mark Rey
Keyword(s):  
Timber Harvest ◽  
Stream Habitat ◽  
Southeast Alaska

Advances in Understanding Landscape Influences on Freshwater Habitats and Biological Assemblages

2019 ◽  
Keyword(s):  
Forested Wetlands ◽  
Timber Harvest ◽  
Large Wood ◽  
Catchment Scale ◽  
Southeast Alaska ◽  
Riparian Management ◽  
Freshwater Habitats ◽  
Study Sites ◽  
Landscape Attributes ◽  
Landscape Influences

<i>Abstract.</i>—Currently, much is known about influences of landscape attributes, including timber harvest practices, on large wood dynamics in streams. Comparatively, much less is known about influences of catchment attributes on Southeast Alaska streams, in part because of a historical lack of consistent catchment-scale data available for the region. As in forested regions elsewhere, large wood is an important resource to stream habitats and fishes in Southeast Alaska. Therefore, the purpose of this study was to characterize catchment-scale influences, including various timber harvest practices, on large wood in Southeast Alaska stream sites. We delineated local catchment boundaries for all stream reaches in the region and summarized landscape influences, including natural and harvest-related attributes in local and network catchments. Relative amounts of variation in four large wood habitat variables explained by natural versus harvest practice-related landscape attributes were evaluated to compare different influences on 28 randomly selected study sites. We used those results to predict variation in large wood variables from our sites through use of both natural and harvest practice-related catchment attributes to identify those that may be most influential to large wood. Natural characteristics, including catchment area, deciduous forests, forested wetlands, and catchment slope, all had significant influences on large wood variables, as did various measures of contemporary and historical timber harvest practices. We found that large wood length was positively related to conventional harvest after 1990, suggesting the potential effectiveness of contemporary logging regulations in protecting large wood characteristics. In our study, both natural and timber harvest practice-related attributes had measureable influences on stream habitat, underscoring the importance of considering catchment-scale attributes, including riparian management schemes, for managing Southeast Alaska streams.

TIMBER HARVEST TRANSFORMS ECOLOGICAL ROLES OF SALMON IN SOUTHEAST ALASKA RAIN FOREST STREAMS

2008 ◽  
Vol 18 (1) ◽  
pp. 4-11 ◽  
Author(s):  
Scott D. Tiegs ◽  
Dominic T. Chaloner ◽  
Peter Levi ◽  
Janine Rüegg ◽  
Jennifer L. Tank ◽  
...  
Keyword(s):  
Rain Forest ◽  
Timber Harvest ◽  
Southeast Alaska ◽  
Ecological Roles ◽  
Forest Streams

Comment on “Does timber harvest influence the dynamics of marine-derived nutrients in Southeast Alaska streams?” 1Original article by Levi et al. appears in Can. J. Fish. Aquat. Sci. 68(8): 1316–1329 and is available at http://www.nrcresearchpress.com/doi/full/10.1139/f2011-067. Reply by Levi et al. appears in Can. J. Fish. Aquat. Sci. 69: this issue, and is available at http://www.nrcresearchpress.com/doi/full/10.1139/f2012-106.

2012 ◽  
Vol 69 (11) ◽  
pp. 1894-1897 ◽  
Author(s):  
C. Rhett Jackson ◽  
Douglas J. Martin
Keyword(s):  
Temporal Variability ◽  
Nutrient Dynamics ◽  
Timber Harvest ◽  
Channel Morphology ◽  
Nutrient Concentrations ◽  
Spatial And Temporal Variability ◽  
Southeast Alaska ◽  
Channel Conditions ◽  
Sample Set ◽  
Marine Derived Nutrients

Levi et al. (2011, Can. J. Fish. Aquat. Sci. 68: 1316–1329) related nutrient concentrations before, during, and after spawning, as well as various measures of channel morphology, to levels of prior timber harvest in seven watersheds on Prince of Wales Island in Southeast Alaska, USA. They assumed that single reaches of seven streams were otherwise similar and that other controls on channel morphology and nutrient dynamics could be ignored relative to the effects of prior timber harvest. In this commentary we show that the seven watersheds were not similar and that the sample set was too small to address geomorphic variability unrelated to timber harvest. Levi et al. failed to consider adequately the natural drivers of spatial and temporal variability in channel morphology and to consider stronger alternate hypotheses for observed channel conditions.

Does timber harvest influence the dynamics of marine-derived nutrients in Southeast Alaska streams?

2011 ◽  
Vol 68 (8) ◽  
pp. 1316-1329 ◽  
Author(s):  
Peter S. Levi ◽  
Jennifer L. Tank ◽  
Scott D. Tiegs ◽  
Janine Rüegg ◽  
Dominic T. Chaloner ◽  
...  
Keyword(s):  
Nutrient Concentration ◽  
Pacific Salmon ◽  
Timber Harvest ◽  
Nutrient Export ◽  
Southeast Alaska ◽  
Particulate Nitrogen ◽  
Nutrient Delivery ◽  
Before And After ◽  
Nutrient Subsidies ◽  
Marine Derived Nutrients

Streams often rely on nutrient subsidies, and variation in nutrient delivery may alter the ecosystem response. Pacific salmon (Oncorhynchus spp.) provide marine-derived nutrients to their natal streams but also cause benthic disturbance, with the net effect determined by watershed and stream characteristics. To understand the factors contributing to variation in salmon-derived nutrients (SDN), we studied nutrient concentration and export in seven streams with varying physical characteristics due to timber harvest (e.g., channel complexity) over three years in Southeast Alaska, USA. Salmon increased concentrations and export of dissolved and particulate nitrogen, phosphorus, and carbon, but the magnitude of increase varied up to 41-fold among streams. The density of live salmon best predicted the increase in nutrient concentration and export, whereas the density of carcasses had a negligible effect. Nutrient export was predicted by transient storage before and after the salmon run. Streams in harvested watersheds with simplified channels had greater nutrient export than those in pristine watersheds with complex channels. However, enrichment from salmon overrode the effect of timber harvest on export during the run. Our study demonstrates that enrichment via SDN is short-lived and related to run size, whereas timber harvest and carcasses exert little influence on SDN dynamics.

Reply to comment by Jackson and Martin on “Does timber harvest influence the dynamics of marine-derived nutrients in Southeast Alaska streams?” 1Original article by Levi et al. appears in Can. J. Fish. Aquat. Sci. 68(8): 1316–1329 and is available at http://www.nrcresearchpress.com/doi/full/10.1139/f2011-067. Comment by Jackson and Martin appears in Can. J. Fish. Aquat. Sci. 69: this issue, and is available at http://www.nrcresearchpress.com/doi/full/10.1139/f2012-104.

2012 ◽  
Vol 69 (11) ◽  
pp. 1898-1901
Author(s):  
Peter S. Levi ◽  
Jennifer L. Tank ◽  
Scott D. Tiegs ◽  
Janine Rüegg ◽  
Dominic T. Chaloner ◽  
...  
Keyword(s):  
Natural Variation ◽  
Nutrient Dynamics ◽  
Sampling Design ◽  
Timber Harvest ◽  
Usda Forest Service ◽  
Southeast Alaska ◽  
Watershed Characteristics ◽  
Stream Geomorphology ◽  
Alternative Hypotheses

The stated goal of Levi et al. (2011, Can. J. Fish. Aquat. Sci. 68: 1316–1329) was to determine the influence of geomorphic complexity on the dynamics of salmon-derived nutrients. We studied seven streams in Southeast Alaska with varying degrees of historical (mid-1900s) timber harvest and, as a result, differences in stream geomorphology. In a comment on our study, Jackson and Martin (2012, Can. J. Fish. Aquat. Sci. 69: this issue) suggest that the geomorphic complexity we ascribe to timber harvest may be due to natural variation in watershed characteristics and offer alternative hypotheses. We sought to reduce the natural variation among our study streams by using a stratified sampling design (i.e., selecting reaches classified as floodplain 4 or 5 by the USDA Forest Service), but acknowledge that, as with any ecological field study, alternative hypotheses may exist to explain observed patterns in ecological responses. We maintain that our study design was sufficiently robust (i.e., 300 m reaches studied in seven streams for 3 years, totaling 21 stream-years) to draw inferences about the influence of salmon on streamwater nutrients and, secondarily, the role of geomorphic variation in mediating nutrient dynamics. Our data also support our finding that the legacy of timber harvest altered nutrient dynamics in salmon-bearing streams via alterations to stream geomorphology that were quantifiable.

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