About This Project

Rising stream temperatures increase fish metabolic demand and stress populations. We propose using high-resolution LiDAR to model current and future stream temperatures in Southeast Alaska, helping resource managers identify critical salmon survival habitat. We hypothesize this approach will reveal previously unrecognized cold-water refuges essential for salmon survival under future warming scenarios.

Ask the Scientists

What is the context of this research?

Southeast Alaska faces a projected temperature increase of 3 to 5°C over the next 50 years, threatening cold-water-dependent aquatic organisms and the local communities that rely on them (Beaudreau et al. 2019, Oke et al. 2020). This climate shift is expected to alter the timing and spatial patterns of suitable temperatures for salmon spawning, incubation, and rearing (Shanley and Albert 2014, Taylor 2007, Bryant 2009). We hypothesize that suitable thermal regimes will shift toward higher elevations and latitudes, ultimately reducing total available habitat.

This study will demonstrate the proven spatial and temporal prediction capabilities necessary to inform policymakers and secure funding for a region-wide network. Such a network is essential to protecting this major salmon-producing region.

What is the significance of this project?

Rising stream temperatures increase metabolic demand on salmonids, leading to an increase in oxygen uptake as oxygen availability decreases, causing stress. Rising air temperatures from climate change are linked to increasing water temperature, especially during the summer months (Isaak et al. 2012, 2017; Fuller et al. 2024). For decision makers to better understand stream temperature impacts that can vary within a basin and make well informed adaptive management decisions, an accurate thermalscape is required.

Here we propose empirically modeling current and future stream temperatures at the reach scale by incorporating both atmospheric and stream reach characteristics (Piotrowski et al. 2021). This modeling approach will use current high resolution liDAR for the entire riverscape to help resource managers reliably identify thermal refugia and potential thermal risks for salmon populations.

What are the goals of the project?

The objective of the liDAR thermalscape temperature study is to 1) maintain a summer temperature monitoring network across an entire HUC 12 stream network, 2) use a spatial stream network (SSN) model to develop riverscape stream temperature maps (e.g., maximum 7-day average daily mean: Max7DADM) that can be used to track spatial and temporal changes in stream temperature as well as predict spatial temperature regimes in basins with similar climate/physiographic characteristics (Isaak et al. 2010, 2014, 2017; Fuller et al. 2024), and 3) evaluate climate change predictions of stream temperature with empirical stream temperature data (Fuller et al. 2022).