This is a repository copy of Ten people-centered rules for socially sustainable ecosystem restoration.

The subpopulation of white sturgeon Acipenser transmontanus in the Canadian portion of the Columbia River between Hugh L. Keenleyside Dam and the U.S.-Canada border has been identified as endangered, with nearly 30 consecutive years of consistent recruitment failure. The objectives of this study were to determine the status and population attributes of this subpopulation. We estimated survival rates and abundance using catch-curve analysis and mark-recapture models. An annual survival rate of 89% (95% confidence interval [CI], 88-90%) was estimated for the subpopulation using catch-curve analysis for the time period 1993-2004. The survival rates estimated from the mark-recapture data were obtained using modelaveraged parameter estimates from a multistrata Cormack-Jolly-Seber model. The annual survival rate from the mark-recapture model was estimated at 97% (95% CI, 92-99%) from 1993 to 2004. The mark-recapture methods estimated abundance for 2004 to be 1,157 individuals (95% CI, 414-1,900). The mark-recapture data suggest that the white sturgeon have low migration rates, ranging from 3% to 5% among sections of the river. Despite high estimated survival, high uncertainty as to the future viability of the white sturgeon subpopulation in this portion of the river remains, as natural recruitment is poor. The fish continue to age, and size and age-frequency data suggest that recruitment failure continues in this subpopulation with minimal presence of wild juvenile or subadult white sturgeon detected.

Stranding of fish due to flow reductions has been documented in the near shore of the Columbia and Kootenay Rivers, Canada, and can result in sub-lethal or lethal effects on fish. Ten years (1999)(2000)(2001)(2002)(2003)(2004)(2005)(2006)(2007)(2008)(2009)) of monitoring data have been collected at sites below two hydro-electric dams (Hugh-L-Keenleyside and Brilliant Dam) following flow reductions. A generalized linear mixed effects model analysed the probability of a stranding event in relation to environmental and operational variables including the rate of change in the water levels, the duration of shoreline inundation prior to a reduction (wetted history), the river stage, the magnitude of the reduction, distance downstream from the dam, time of day, day of year (season) and whether a site had been physically altered to mitigate stranding. The results demonstrated statistically significant effects on stranding risk from minimum river stage, day of the year and whether a site had been physically re-contoured. The combination of investigated factors giving the highest probability of stranding was a large magnitude reduction completed in the afternoon in midsummer, at low water levels when the near shore had been inundated for a long period. This research is significant in its approach to assessing years of ecosystem scale monitoring data and using the modelling results to determine ways for these findings to be applied in regulated river management to minimize fish stranding. It also highlighted data gaps that require addressing and provides ecosystem scale results to compare with stranding studies carried out in mesocosms.

Juvenile fish can strand in pools or in interstitial spaces when the water elevation drops in regulated rivers due to flow reductions. Three years of summer and winter experiments on the Columbia and Kootenay Rivers (Canada) assessed the effect of the rate of change in water level (ramping rate) on the probability of pool and interstitial stranding for juvenile (<100 mm) fish. The factors of wetted history of the site, time of day, natural fish density and the occurrence of a conditioning reduction prior to the operational reduction were also examined for their effect on stranding. Experimental net pens were constructed to test these factors in situ in the varial zones of the two rivers. Linear models with plausible additive combinations of the potential explanatory factors and a null model were fitted to the logistically transformed data and ranked using the second-order Akaike Information Criterion (AIC c ). The null model was the top ranked model for the interstitial stranding analyses, highlighting that none of the factors tested were significant variables in predicting the probability of stranding. Natural fish density, wetted history of the site, ramping rate and the presence of a conditioning reduction were variables included in the top three ranking models for the pool stranding analyses. Probability of pool stranding in summer was reduced by the occurrence of a conditioning reduction prior to the operational reduction. Higher natural fish density, longer periods of wetted history and higher ramping rates all led to higher probabilities of pool stranding.

Invasive species have led to precipitous declines in biodiversity, especially in island systems. Brown (Rattus norvegicus) and black rats (R. rattus) are among the most invasive animals on the planet, with eradication being the primary tool for established island populations. The need for increased research for defining eradication units and monitoring outcomes has been highlighted as a means to maximize success. HaidaGwaii is an archipelago ~100 km off the northern coast of British Columbia, Canada, that hosts globally significant breeding populations of seabirds that are at risk due to invasive rats. Here, we paired sampling of brown (n = 287) and black (n = 291) rats across the Haida Gwaii archipelago with genotyping by sequencing (10,686 SNPs) to investigate patterns of population connectivity and infer levels/direction of gene flow among invasive rat populations in Haida Gwaii. We reconstructed three regional clusters for both species (north, central and south), with proximate populations within regions being largely more related than those that were more distant, consistent with predictions from island biogeography theory. Population assignment of recently detected individuals post-eradication on Faraday, Murchison and the Bischof Islands revealed all were re-invaders from Lyell Island, rather than being on-island survivors. Based on these results, we identified six eradication units constituting single or clusters of islands that would limit the potential for reinvasion, some of which will need to be combined with biosecurity measures. Overall, our results highlight the importance of targeted research prior to conducting eradications and demonstrate a framework for applying population genomics for guiding invasive species management in island systems. K E Y W O R D Sconservation, invasive species, island biogeography, population genetics, Rattus norvegicus, Rattus rattus