Tools for Assessing Climate Impacts on Fish and Wildlife

Climate change is already affecting many fish and wildlife populations. Managing these populations requires an understanding of the nature, magnitude, and distribution of current and future climate impacts. Scientists and managers have at their disposal a wide array of models for projecting climate impacts that can be used to build such an understanding. Here, we provide a broad overview of the types of models available for forecasting the effects of climate change on key processes that affect fish and wildlife habitat (hydrology, fire, and vegetation), as well as on individual species distributions and populations. We present a framework for how climate-impacts modeling can be used to address management concerns, providing examples of model-based assessments of climate impacts on salmon populations in the Pacific Northwest, fire regimes in the boreal region of Canada, prairies and savannas in the Willamette Valley-Puget Sound Trough-Georgia Basin ecoregion, and marten Martes americana populations in the northeastern United States and southeastern Canada. We also highlight some key limitations of these models and discuss how such limitations should be managed. We conclude with a general discussion of how these models can be integrated into fish and wildlife management

Long-Term Impacts of Forest Management Practices under Climate Change on Structure, Composition, and Fragmentation of the Canadian Boreal Landscape

Forest harvesting and fire are major disturbances in boreal forests. Forest harvesting has modified stand successional pathways, which has led to compositional changes from the original conifer-dominated forests to predominantly mixed and hardwood forests. Boreal fire regimes are expected to change with future climate change. Using the LANDIS-II spatially explicit landscape model, we evaluated the effects of forest management scenarios and projected fire regimes under climate change in northeastern Canadian boreal forests, and we determined the subsequent alteration in stand- and landscape-level composition, succession, and spatial configuration of boreal forests. We observed that, in contrast to successional pathways that followed fire, successional pathways that followed forest harvesting favored mixed forests with a prevalence of shade-intolerant hardwoods for up to 300 y after harvesting. This trend was exacerbated under climate change scenarios where forests became dominated by hardwood species, particularly in ecoregions where these species were found currently in low abundance. Our results highlight the failure of existing forest management regimes to emulate the effects of natural disturbance regimes on boreal forest composition and configuration. This illustrates the risks to maintaining ecosystem goods and services over the long term and the exacerbation of this trend in the context of future climate change.Funding: Natural Sciences and Engineering Research Council of Canada (Grant number 125559117), GreenFirst, and West Fraser Timber Co. Ltd. Acknowledgments: We would like to thank the Quebec Ministère des Forêts, de la Faune et des Parcs (Ministry of Forests, Wildlife and Parks) and its forest inventory department for providing the digital inventory data to calibrate LANDIS-II. The Sustainable Forest Management UQAT/UQAM Chair (SFM Chair) also helped this project by providing all technical support. We thank Dominic Cyr for their helpful comments and suggestions for this study. We are also grateful to Johana Herrera and Javier Peinado for the compilation and construction of some of the input data sets and to Thomas A. Gavin and Murray Hay for the English revision. This manuscript is part of the Ph.D. thesis of Eliana Cristina Molina at the University of Quebec in Abitibi-Témiscamingue. A version of this manuscript is available online at depositium.uqat.ca

Influence of Forest Management Regimes on Forest Dynamics in the Upstream Region of the Hun River in Northeastern China

Balancing forest harvesting and restoration is critical for forest ecosystem management. In this study, we used LANDIS, a spatially explicit forest landscape model, to evaluate the effects of 21 alternative forest management initiatives which were drafted for forests in the upstream region of the Hun River in northeastern China. These management initiatives included a wide range of planting and harvest intensities for Pinus koraiensis, the historically dominant tree species in the region. Multivariate analysis of variance, Shannon's Diversity Index, and planting efficiency (which indicates how many cells of the target species at the final year benefit from per-cell of the planting trees) estimates were used as indicators to analyze the effects of planting and harvesting regimes on forests in the region. The results showed that the following: (1) Increased planting intensity, although augmenting the coverage of P. koraiensis, was accompanied by decreases in planting efficiency and forest diversity. (2) While selective harvesting could increase forest diversity, the abrupt increase of early succession species accompanying this method merits attention. (3) Stimulating rapid forest succession may not be a good management strategy, since the climax species would crowd out other species which are likely more adapted to future climatic conditions in the long run. In light of the above, we suggest a combination of 30% planting intensity with selective harvesting of 50% and 70% of primary and secondary timber species, respectively, as the most effective management regime in this area. In the long run this would accelerate the ultimate dominance of P. koraiensis in the forest via a more effective rate of planting, while maintaining a higher degree of forest diversity. These results are particularly useful for forest managers constrained by limited financial and labor resources who must deal with conflicts between forest harvesting and restoration

EFFECTS OF LAND COVER, WATER REDISTRIBUTION, AND TEMPERATURE ON ECOSYSTEM PROCESSES IN THE SOUTH PLATTE BASIN

Over one‐third of the land area in the South Platte Basin of Colorado, Nebraska, and Wyoming, has been converted to croplands. Irrigated cropland now comprises 8% of the basin, while dry croplands make up 31%. We used the RHESSys model to compare the changes in plant productivity and vegetation‐related hydrological processes that occurred as a result of either land cover alteration or directional temperature changes (−2°C, +4°C). Land cover change exerted more control over annual plant productivity and water fluxes for converted grasslands, while the effect of temperature changes on productivity and water fluxes was stronger in the mountain vegetation. Throughout the basin, land cover change increased the annual loss of water to the atmosphere by 114 mm via evaporation and transpiration, an increase of 37%. Both irrigated and nonirrigated grains became active earlier in the year than shortgrass steppe, leading to a seasonal shift in water losses to the atmosphere. Basin‐wide photosynthesis increased by 80% due to grain production. In contrast, a 4°C warming scenario caused annual transpiration to increase by only 3% and annual evaporation to increase by 28%, for a total increase of 71 mm. Warming decreased basin‐wide photosynthesis by 16%. There is a large elevational range from east to west in the South Platte Basin, which encompasses the western edge of the Great Plains and the eastern front of the Rocky Mountains. This elevational gain is accompanied by great changes in topographic complexity, vegetation type, and climate. Shortgrass steppe and crops found at elevations between 850 and 1800 m give way to coniferous forests and tundra between 1800 and 4000 m. Climate is increasingly dominated by winter snow precipitation with increasing elevation, and the timing of snowmelt influences tundra and forest ecosystem productivity, soil moisture, and downstream discharge. Mean annual precipitation of \u3c500 mm on the plains below 1800 m is far less than potential evapotranspiration of 1000–1500 mm and is insufficient for optimum plant productivity. The changes in water flux and photosynthesis from conversion of steppe to cropland are the result of redistribution of snowmelt water from the mountains and groundwater pumping through irrigation projects

La dynamique du paysage forestier boréal mixte en réponse aux feux et à l'aménagement forestier sous l'influence des changements climatiques

Le paysage forestier boréal dominé par la forêt mixte est le résultat des interactions complexes des conditions abiotiques, de la succession et des régimes de perturbations, qu’influencent les processus écologiques qui opèrent au niveau du peuplement et à l’échelle du paysage. Les changements climatiques prévus pour les prochains siècles devraient modifier les régimes de perturbations naturelles tels que les incendies de forêt, affectant le flux de bois vers les marchés de produits ligneux. C’est pour cette raison que la gestion des forêts boréales mixtes a suscité une préoccupation généralisée concernant le maintenant de sa biodiversité, sa résilience et sa capacité d’adaptation à conserver les avantages sociaux et économiques qu’elles procurent à la société. Cette préoccupation a conduit à proposer une modification de l'exploitation dite traditionnelle vers une approche d’aménagement forestier écosystémique, qui tente d'imiter les patrons de perturbations naturelles afin de conserver la forêt à l’intérieur des limites historiques de variation. En dépit de tous ces efforts, au cours des dernières décennies dans l'est du Canada, la forêt mixte est passée d'un paysage dominé par la forêt mature vers un paysage fragmenté avec une quantité croissante de peuplements à prédominance de feuillus. Toutefois, notre compréhension des variations spatiotemporelles des paysages forestiers et des caractéristiques des peuplements issus après feu et après récolte demeure insuffisante. L'objectif de cette thèse était de caractériser les changements à moyen terme des mosaïques de forêts mixtes de l'est du Canada et d'améliorer notre connaissance des relations entre ces changements et les variations attendues des feux de forêt sous l’effet des changements climatiques ainsi que du régime de perturbations anthropiques. La première étape pour atteindre cet objectif a été de comprendre la dynamique historique du paysage dans un gradient nord-sud de forêts mixtes de l’est du Canada. Pour cette raison, le chapitre 2 présente une étude historique de l’hétérogénéité du paysage forestier, mesuré en termes de composition et configuration du paysage ainsi que leur interaction avec les feux de forêt historiques dans un paysage aménagé. En utilisant les images Landsat de 1985 à 2013, la cartographie et des mesures spatiales nous avions suivi l’évolution de la composition dans le temps des forêts selon 4 classes : résineux, résineux mixtes à dominance résineuse, mixte à dominance feuillue et feuillus. Cette étude montre que la composition résineuse a dominé la mosaïque en 1985 et représentait un tiers de la superficie de l'étude. De plus, la classe résineuse a enregistré la plus forte diminution avec un taux de 1,7% par an par rapport aux autres couvertures forestières. Les mesures indiquent que les forêts résineuses matures, qui dominaient auparavant le paysage dans l'est du Canada, ont été principalement transformées par les pratiques forestières en un paysage plus hétérogène et fragmenté. Le chapitre 3 détaille le modèle de paysage forestier LANDIS-II utilisé pour évaluer les relations entre les feux de forêt et l’aménagement forestier sous scénarios de réchauffement climatique futur (RCP 2.6,RCP 4.5 et RCP 8.5), via la biomasse forestière (AGB) et la productivité primaire nette (ANPP). Les projections du modèle ont démontré que les régimes de perturbation sont les variables les plus significatives qui déterminent les variations de l'AGB et de l'ANPP. L’aménagement forestier apparait comme le facteur le plus important des variations observées dans les forêts du sud du gradient comparativement au nord, probablement parce que cette région présente des forêts plus âgées et avec une composition d’intérêt commercial pour respecter la possibilité forestière. À l’opposé, les forêts du nord du gradient présentaient un effet mixte du changement climatique et de l’aménagement forestier sur l'AGB et l'ANPP, probablement parce qu'un grand nombre de zones propices à la récolte avaient déjà été brulées, limitant ainsi la quantité du territoire disponible pour la récolte. En général, bien que l'on s'attende à une augmentation des superficies brulées en raison du changement climatique, l'intensification de l’aménagement forestier semble être le principal facteur de l'augmentation des feuillus et des peuplements mixtes et de la diminution des peuplements résineux, ainsi que de la diminution de la AGB et ANPP, principalement dans les forêts du sud. Le chapitre 4 détaille l'utilisation de LANDIS-II pour modéliser les trajectoires de succession de la gestion post-feu et post-aménagement suite aux scénarios de changement climatique. L’évolution de l’AGB post-perturbations nous a permis de constater que, contrairement aux perturbations causées par les feux, l’aménagement forestier a modifié les voies de succession conduisant à des changements de composition allant de forêts à prédominance de feuillus à une forêt mixte favorisant la prévalence d'essences de feuillus, même après 300 ans. Cette tendance est exacerbée par les scénarios de changement climatique, qui donneront un avantage aux forêts dominées par des espèces intolérantes à l'ombre, en particulier dans les écorégions où elles sont peu présentes (forêts mixtes centrales et septentrionales de la zone d’étude). De plus, ces pratiques d’aménagement conduisent à des indices de formes de forêt plus sinueuses au niveau spatial du paysage, indiquant une augmentation de la fragmentation. Les résultats obtenus mettent en évidence l'échec des pratiques d’aménagement actuelles à imiter la succession naturelle après feu et compromettent le maintien des biens et des services de ces écosystèmes. Les changements climatiques prévus pour le prochain siècle devraient modifier les régimes de perturbations naturelles (tels que les feux de forêt). En outre, il existe des activités d’aménagement telles que la récupération du bois à des fins industrielles qui perturbent les forêts pour satisfaire la demande croissante de produits ligneux. Nos résultats suggèrent que l'approvisionnement en bois à long terme serait menacé dans l'est du Canada. Par conséquent, certaines stratégies devraient être mises en oeuvre pour adapter l’aménagement des forêts aux changements climatiques attendus et à maintenir l'avenir des forêts

Importance of succession, harvest, and climate change in determining future composition in U.S. Central Hardwood Forests

Most temperate forests in U.S. are recovering from heavy exploitation and are in intermediate successional stages where partial tree harvest is the primary disturbance. Changes in regional forest composition in response to climate change are often predicted for plant functional types using biophysical process models. These models usually simplify the simulation of succession and harvest and may not consider important species-specific demographic processes driving forests changes. We determined the relative importance of succession, harvest, and climate change to forest composition changes in a 125-million ha area of the Central Hardwood Forest Region of U.S. We used a forest landscape modeling approach to project changes in density and basal area of 23 tree species due to succession, harvest, and four climate scenarios from 2000 to 2300. On average, succession, harvest, and climate change explained 78, 17, and 1% of the variation in species importance values (IV) at 2050, respectively, but their contribution changed to 46, 26, and 20% by 2300. Climate change led to substantial increases in the importance of red maple and southern species (e.g., yellow-poplar) and decreases in northern species (e.g., sugar maple) and most of widely distributed species (e.g., white oak). Harvest interacted with climate change and accelerated changes in some species (e.g., increasing southern red oak and decreasing American beech) while ameliorated the changes for others (e.g., increasing red maple and decreasing white ash). Succession was the primary driver of forest composition change over the next 300 years. The effects of harvest on composition were more important than climate change in the short term but climate change became more important than harvest in the long term. Our results show that it is important to model species-specific responses when predicting changes in forest composition and structure in response to succession, harvest, and climate change

Moving Beyond Static Species Distribution Models in Support of Conservation Biogeography

Aim: To demonstrate that multi-modeling methods have effectively been used to combine static species distribution models (SDM), predicting the geographical pattern of suitable habitat, with dynamics landscape and population models in order to forecast the impacts of environmental change on species, an important goal of conservation biogeography. Methods: Three approaches were considered: a) incorporating models of species migration in order to understand the ability of a species to occupy suitable habitat in new locations; b) linking models of landscape disturbance and succession to models of habitat suitability; and, c) fully linking models of habitat suitability, habitat dynamics and spatially-explicit population dynamics. Results: Linking species-environment relationships, landscape dynamics and population dynamics in a multi-modeling framework allows the combined impacts of climate change (affecting species distribution and vital rates) and land cover dynamics (land use change, altered disturbance regimes) on species be predicted. This approach is only feasible if the life history parameters and habitat requirements of the species are well understood. Main Conclusions: Forecasts of the impacts of global change on species have been improved by considering multiple causes. A range of methods are available to address the interactions of changing habitat suitability, habitat dynamics and population response that vary in their complexity, realism and data requirements.

Modeling Tree Species Distribution and Dynamics Under a Changing Climate, Natural Disturbances, and Harvest Alternatives in the Southern United States

Forests in the southern United States with diverse forest ownership entities are facing threats associated with climate change and natural disturbances. This study represented the relationship between climate and species dominance, predicted future species distribution probability under a changing climate, and projected forest dynamics under ownership-based management regimes. Correlative statistics and mechanistic modeling approaches are implemented. Temporal scale includes the recent past 40 years and the future 60 years; spatial scale downscaled from southern United States to the coastal region of the northern Gulf of Mexico. In the southern United States, dominance of four major pine species experienced shifts from 1970 to 2000; quantile regression models built on the relationships among pine dominance and climatic variables can be used to predict future southern pine dominance. Furthermore, multiple climate envelope models (CEMs) were constructed for nineteen native and one invasive tree species (Chinese tallow, Triadica sebifera) to predict species establishment probabilities (SEPs) on the various land types from 2010 to 2070. CEMs achieved both predictive consistency and ecological conformity in estimating SEPs. Chinese tallow was predicted to have the highest invasionability in longleaf/slash pine and oak/gum/cypress forests during the next 60 years. Forest dynamics, in the coastal region, was projected by linking CEMs and forest landscape model (LANDIS) to evaluate ownership-based management regimes under climate change and natural disturbances. The dominance of forest species will diminish due to climate change and natural disturbances at both spatial scales—in the coastal region and non-industrial private forest (NIPF). No management on NIPF land was predicted to substantially increase the ratio of occupancy area between pines and oaks, but moderate and intensive management regimes were not significantly different. Pines are expected to be more resistant than oaks by maintaining stable age structures, which matched the forest inventory records. Overall, this study projected a future of southern forests on climate-species relationship, invasion risks, and forest community dynamics under multiple scenarios in the United States. Such knowledge could assist forest managers and landowners in foreseeing the future and making effective management prescriptions to mitigate potential threats

Importance of succession, harvest, and climate change in determining future composition in U.S. Central Hardwood Forests

Most temperate forests in U.S. are recovering from heavy exploitation and are in intermediate successional stages where partial tree harvest is the primary disturbance. Changes in regional forest composition in response to climate change are often predicted for plant functional types using biophysical process models. These models usually simplify the simulation of succession and harvest and may not consider important species-specific demographic processes driving forests changes. We determined the relative importance of succession, harvest, and climate change to forest composition changes in a 125-million ha area of the Central Hardwood Forest Region of U.S. We used a forest landscape modeling approach to project changes in density and basal area of 23 tree species due to succession, harvest, and four climate scenarios from 2000 to 2300. On average, succession, harvest, and climate change explained 78, 17, and 1% of the variation in species importance values (IV) at 2050, respectively, but their contribution changed to 46, 26, and 20% by 2300. Climate change led to substantial increases in the importance of red maple and southern species (e.g., yellow-poplar) and decreases in northern species (e.g., sugar maple) and most of widely distributed species (e.g., white oak). Harvest interacted with climate change and accelerated changes in some species (e.g., increasing southern red oak and decreasing American beech) while ameliorated the changes for others (e.g., increasing red maple and decreasing white ash). Succession was the primary driver of forest composition change over the next 300 years. The effects of harvest on composition were more important than climate change in the short term but climate change became more important than harvest in the long term. Our results show that it is important to model species-specific responses when predicting changes in forest composition and structure in response to succession, harvest, and climate change