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Dymond C.C.,British Columbia Ministry of forests | Beukema S.,ESSA Technologies Ltd | Nitschke C.R.,University of Melbourne | Coates K.D.,British Columbia Ministry of forests | Scheller R.M.,Portland State University

Management of temperate forests has the potential to increase carbon sinks and mitigate climate change. However, those opportunities may be confounded by negative climate change impacts. We therefore need a better understanding of climate change alterations to temperate forest carbon dynamics before developing mitigation strategies. The purpose of this project was to investigate the interactions of species composition, fire, management, and climate change in the Copper-Pine Creek valley, a temperate coniferous forest with a wide range of growing conditions. To do so, we used the LANDIS-II modelling framework including the new Forest Carbon Succession extension to simulate forest ecosystems under four different productivity scenarios, with and without climate change effects, until 2050. Significantly, the new extension allowed us to calculate the net sector productivity, a carbon accounting metric that integrates aboveground and belowground carbon dynamics, disturbances, and the eventual fate of forest products. The model output was validated against literature values. The results implied that the species optimum growing conditions relative to current and future conditions strongly influenced future carbon dynamics. Warmer growing conditions led to increased carbon sinks and storage in the colder and wetter ecoregions but not necessarily in the others. Climate change impacts varied among species and site conditions, and this indicates that both of these components need to be taken into account when considering climate change mitigation activities and adaptive management. The introduction of a new carbon indicator, net sector productivity, promises to be useful in assessing management effectiveness and mitigation activities. © Author(s) 2016. Source

Connors B.M.,Simon Fraser University | Connors B.M.,ESSA Technologies Ltd | Cooper A.B.,Simon Fraser University | Peterman R.M.,Simon Fraser University | Dulvy N.K.,Simon Fraser University
Proceedings of the Royal Society B: Biological Sciences

Abundance trends are the basis for many classifications of threat and recovery status, but they can be a challenge to interpret because of observation error, stochastic variation in abundance (process noise) and temporal autocorrelation in that process noise. To measure the frequency of incorrectly detecting a decline (false-positive or false alarm) and failing to detect a true decline (falsenegative), we simulated stable and declining abundance time series across several magnitudes of observation error and autocorrelated process noise. We then empirically estimated the magnitude of observation error and autocorrelated process noise across a broad range of taxa and mapped these estimates onto the simulated parameter space. Based on the taxawe examined, at low classification thresholds (30% decline in abundance) and short observation windows (10 years), false alarms would be expected to occur, on average, about 40% of the time assuming density-independent dynamics, whereas false-negatives would be expected to occur about 60% of the time. However, false alarms and failures to detect true declines were reduced at higher classification thresholds (50%or 80% declines), longer observation windows (20, 40, 60 years), and assuming density-dependent dynamics. The lowest false-positive and false-negative rates are likely to occur for large-bodied, long-lived animal species. © 2014 The Authors Published by the Royal Society. All rights reserved. Source

Peacock S.J.,University of Alberta | Connors B.M.,Simon Fraser University | Connors B.M.,ESSA Technologies Ltd | Krkosek M.,University of Otago | And 3 more authors.
Proceedings of the Royal Society B: Biological Sciences

The impact of parasites on hosts is invariably negative when considered in isolation, but may be complex and unexpected in nature. For example, if parasites make hosts less desirable to predators then gains from reduced predation may offset direct costs of being parasitized.We explore these ideas in the context of sea louse infestations on salmon. In Pacific Canada, sea lice can spread from farmed salmon to migrating juvenilewild salmon. Low numbers of sea lice can cause mortality of juvenile pink and chum salmon. For pink salmon, this has resulted in reduced productivity of river populations exposed to salmon farming. However, for chum salmon, we did not find an effect of sea louse infestations on productivity, despite high statistical power. Motivated by this unexpected result, we used a mathematical model to show how a parasite-induced shift in predation pressure from chum salmon to pink salmon could offset negative direct impacts of sea lice on chumsalmon. This shift in predation is proposed to occur because predators show an innate preference for pink salmon prey. This preference may be more easily expressed when sea lice compromise juvenile salmon hosts, making themeasier to catch.Our results indicate how the ecological context of host-parasite interactions may dampen, or even reverse, the expected impact of parasites on host populations. © 2013 The Author(s). Source

Price M.H.H.,SkeenaWild Conservation Trust | Connors B.M.,ESSA Technologies Ltd | Connors B.M.,Simon Fraser University

The enhancement of salmon populations has long been used to increase the abundance of salmon returning to spawn and/ or to be captured in fisheries. However, in some instances enhancement can have adverse impacts on adjacent non-enhanced populations. In Canada's Skeena watershed, smolt-to-adult survival of Babine Lake sockeye from 1962-2002 was inversely related to the abundance of sockeye smolts leaving Babine Lake. This relationship has led to the concern that Babine Lake smolt production, which is primarily enhanced by spawning channels, may depress wild Skeena (Babine and non-Babine) sockeye populations as a result of increased competition between wild and enhanced sockeye smolts as they leave their natal lakes and co-migrate to sea. To test this hypothesis we used data on Skeena sockeye populations and oceanographic conditions to statistically examine the relationship between Skeena sockeye productivity (adult salmon produced per spawner) and an index of Babine Lake enhanced smolt abundance while accounting for the potential influence of early marine conditions. While we had relatively high power to detect large effects, we did not find support for the hypothesis that the productivity of wild Skeena sockeye is inversely related to the abundance of enhanced sockeye smolts leaving Babine Lake in a given year. Importantly, life-time productivity of Skeena sockeye is only partially explained by marine survival, and likely is an unreliable measure of the influence of smolt abundance. Limitations to our analyses, which include: (1) the reliance upon adult salmon produced per spawner (rather than per smolt) as an index of marine survival, and (2) incomplete age structure for most of the populations considered, highlight uncertainties that should be addressed if understanding relationships between wild and enhanced sockeye is a priority in the Skeena. © 2014 Price, Connors. Source

Greig L.,ESSA Technologies Ltd | Duinker P.,Dalhousie University
Impact Assessment and Project Appraisal

Inadequate integration and lack of focus have been identified as two main issues plaguing contemporary impact assessment. We agree but argue that these are but two of a plethora of ills that thwart environmental assessment and prevent it from becoming the go-to tool for sustainable development in Canada. We witness ongoing ineffective practice in scoping, impact prediction, significance determination, assessment of cumulative effects, and other elements. Fundamental change is needed in the environmental assessment system to turn it from a shallow adversarial process to a technically rigorous and collaborative one. © 2014 © 2014 IAIA. Source

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