Search

© 2015 The Author(s) Context: More than a century of forest and fire management of Inland Pacific landscapes has transformed their successional and disturbance dynamics. Regional connectivity of many terrestrial and aquatic habitats is fragmented, flows of some ecological and physical processes have been altered in space and time, and the frequency, size and intensity of many disturbances that configure these habitats have been altered. Current efforts to address these impacts yield a small footprint in comparison to wildfires and insect outbreaks. Moreover, many current projects emphasize thinning and fuels reduction within individual forest stands, while overlooking large-scale habitat connectivity and disturbance flow issues. Methods: We provide a framework for landscape restoration, offering seven principles. We discuss their implication for management, and illustrate their application with examples. Results: Historical forests were spatially heterogeneous at multiple scales. Heterogeneity was the result of variability and interactions among native ecological patterns and processes, including successional and disturbance processes regulated by climatic and topographic drivers. Native flora and fauna were adapted to these conditions, which conferred a measure of resilience to variability in climate and recurrent contagious disturbances. Conclusions: To restore key characteristics of this resilience to current landscapes, planning and management are needed at ecoregion, local landscape, successional patch, and tree neighborhood scales. Restoration that works effectively across ownerships and allocations will require active thinking about landscapes as socio-ecological systems that provide services to people within the finite capacities of ecosystems. We focus attention on landscape-level prescriptions as foundational to restoration planning and execution.

We quantified the sum of daily mean temperature above 0 [degrees]C and modeled incubation duration using water temperature data collected at 12 coho salmon (Oncorhynchus kisutch) spawning sites during two incubation periods with cool, snow-dominant conditions and three incubation periods with anomalously warm, rain-transitional conditions, a proxy for a future climate scenario. Warmer water temperatures during warm-rain-transitional winters yielded a 58-day reduction in the median duration of egg incubation; however, the magnitude of change at individual sites varied widely and was controlled by water source. At groundwater-fed sites, temperature variations were strongly attenuated, leading to small interannual differences in incubation duration that were relatively insensitive to short-term changes in air temperature. In contrast, modeled incubation duration was shortened by up to 3 months during warm-rain-transitional winters at precipitation-fed sites. Remarkably, our modeling showed increased uniformity in incubation duration across the landscape during warm-rain-transitional winters. The potential loss of diversity in incubation duration during warmer winters, in isolation, may reduce portfolio effects in this region's coho salmon population by promoting greater synchronization in the time of spawning. Nous avons quantifie la somme des temperatures moyennes quotidiennes superieures a 0 [degrees]C et modelise la duree d'incubation en utilisant des donnees sur la temperature de l'eau obtenues dans 12 lieux de frai de saumons cohos (Oncorhynchus kisutch) durant deux periodes d'incubation caracterisees par des conditions froides dominees par la neige et trois periodes d'incubation caracterisees par des conditions pluvieuses anormalement chaudes de transition, representant un scenario de climat futur. Les temperatures de l'eau plus elevees durant les hivers chauds et pluvieux de transition entrament une baisse de 58 jours de la duree mediane d'incubation des reufs; l'ampleur du changement dans chaque lieu de frai varie toutefois considerablement et est controlee par la source d'eau. Aux sites alimentes par de l'eau souterraine, les variations de temperature sont fortement attenuees, menant a de faibles differences interannuelles de la duree d'incubation relativement insensibles aux changements a court terme de la temperature de l'air. En revanche, la duree d'incubation modelisee est de jusqu'a 3 mois plus courte durant les hivers chauds et pluvieux de transition dans les sites alimentes en eau par les precipitations. Fait a noter, la modelisation fait ressortir une uniformite accrue de la duree d'incubation a l'echelle du paysage durant les hivers chauds et pluvieux de transition. La baisse potentielle de diversite des durees d'incubation durant les hivers chauds pourrait, en soi, reduire les effets de portefeuille dans la population de saumons cohos de la region en favorisant une plus grande synchronisation du moment du frai. [Traduit par la Redaction], Introduction Climate change is already affecting water temperature in freshwater ecosystems that support Pacific salmon (Oncorhynchus spp.) and other cold-water fishes (Schindler et al. 2005; Isaak et al. 2012). Growth [...]

Climate warming poses challenges to native fish, particularly at high latitudes. We used incubation models to explore how interactions between spawning timing and daily varying water temperature affected emergence timing for five species of Pacific salmon in 33 thermally diverse streams in south-central Alaska. Interactions between spawning timing and stream thermal regime led to three different emergence timing responses: (1) "expanded" by typically 2–3 times the duration of the spawning window for summer spawning salmon at streams with a large annual water temperature range; (2) "equal" in duration to the spawning window, regardless of spawning timing, at streams with upwelling groundwater; and (3) "compressed" for late-spawning salmon where water temperature was cooler at spawning than at emergence. Across all sites, a ±15-day range in spawning timing had influence similar to anomalously warm winters (+2 °C to +3 °C) on the emergence timing window. Differences among species, spawning timing, and thermal regimes suggest that a range of adaptations in spawning behavior will likely enable Pacific salmon populations to accommodate shifting thermal regimes during their early life history. [ABSTRACT FROM AUTHOR]

Phenology can be linked to individual fitness, particularly in strongly seasonal environments where the timing of events has important consequences for growth, condition, and survival. We studied the phenology of coho salmon (Oncorhynchus kisutch) hatching and emergence in streams with contrasting thermal variability but in close geographic proximity. Following emergence, we tracked body sizes of cohorts of young-of-year fish until the end of the growing season. Hatch and emergence occurred at the same time among streams with marked variability in thermal regimes. We demonstrate that this can be explained in part by the thermal units accumulated during embryo development. At the end of the first growing season, there were some differences in body size, but overall fish size was similar among streams despite strong differences in thermal regimes. Collectively, these results provide novel insights into the interactions between environmental variability and the early life-history stages of coho salmon, furthering our understanding of the consequences of phenology on growth and survival for individuals within the critical first summer of life.La phenologie peut etre reliee a l'aptitude individuelle, particulierement dans les milieux de forte saisonnalite ou le moment d'evenements a d'importantes consequences sur la croissance, l'embonpoint et la survie. Nous avons etudie la phenologie de l'eclosion et de l'emergence de saumons cohos (Oncorhynchus kisutch) dans des cours d'eau caracterises par differentes variabilites thermiques, mais situes a faible distance les uns des autres. Apres l'emergence, nous avons surveille les tailles du corps de cohortes de jeunes de l'annee jusqu'a la fin de la saison de croissance. L'eclosion et l'emergence se sont produites en meme dans des cours d'eau presentant une variabilite des regimes thermiques marquee. Nous demontrons que cela peut s'expliquer en partie par les unites thermiques accumulees durant le developpement des embryons. Si, a la fin de la premiere saison de croissance, il y avait certaines differences sur le plan de la taille du corps, la taille des poissons etait toutefois globalement semblable d'un cours d'eau a l'autre malgre des regimes thermiques fort differents. Collectivement, ces resultats fournissent de nouveaux renseignements sur les interactions entre la variabilite des conditions ambiantes et les premieres etapes du cycle biologique des saumons cohos, ameliorant ainsi la comprehension des consequences de la phenologie sur la croissance et la survie des individus durant l'etape critique qu'est le premier ete de leur vie. [Traduit par la Redaction], IntroductionThe phenology of transitions in an individual's life cycle can have important consequences for growth and survival, particularly in strongly seasonal environments (Einum and Fleming 2000; Love et al. 2010; [...]