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Aim: Climate change is expected to influence boreal bird communities significantly, notably through changes in forest habitat (composition and age structure), in the coming decades. How these changes will accumulate and interact with anthropogenic disturbances remains an open question for most species. Location: Northeastern Alberta, Canada. Methods: We used the LANDIS‐II forest landscape model to project changes in forest landscapes, and associated bird populations (72 passerine species), according to three climatic scenarios (baseline, RCP 4.5 and RCP 8.5) and three forest harvesting scenarios of differing intensity. Results: Both forest harvesting and climate‐related drivers were projected to have large impacts on bird communities in this region. As a result of climate‐induced increases in fire activity as well as decreased conifer productivity, our simulations projected that an important proportion of Alberta's boreal forests would transition to treeless habitat (i.e. grass‐ or shrub‐dominated vegetation) while many conifer‐dominated stands would likely be replaced by broadleaf tree cover. Consequently, the abundance of bird species associated with open and deciduous habitats were projected to increase. With a strong anthropogenic climate‐forcing scenario (RCP 8.5), sharp declines in abundance of coniferous trees were also projected, particularly in mature and old forest stands, triggering major declines for bird species associated with coniferous and mixedwood forest types. Main conclusions: As the most comprehensive simulation of climate change and harvesting impacts on avian habitats in the North American boreal region to date, our study stresses the importance of considering key habitat characteristics like forest age structure and composition through forest landscape modelling and identifies 18 bird species particularly sensitive to climate change. Our simulations suggest that a change in forest management practices could play an important role in the conservation of boreal bird species vulnerable to climate change. The intensive forest harvesting simulated accelerated declines in bird abundance compared to a "no harvesting" scenario. [ABSTRACT FROM AUTHOR]

Estimating distribution and abundance of species depends on the probability at which individuals are detected. Butterflies are of conservation interest worldwide, but data collected with Pollard walks--the standard for national monitoring schemes--are often analyzed assuming that changes in detectability are negligible within recommended sampling criteria. The implications of this practice remain poorly understood. Here, we evaluated the effects of sampling conditions on butterfly counts from Pollard walks using the Arctic fritillary, a common but cryptic butterfly in boreal forests of Alberta, Canada. We used an open population binomial N-mixture model to disentangle the effects of habitat suitability and phenology on abundance of Arctic fritillaries, and its detectability by sampling different conditions of temperature, wind, cloud cover, and hour of the day. Detectability varied by one order of magnitude within the criteria recommended for Pollard walks (P varying between 0.04 and 0.45), and simulations show how sampling in suboptimal conditions increases substantially the risk of false-absence records (e.g., false-absences are twice as likely than true-presences when sampling 10 Arctic fritillaries at P = 0.04). Our results suggest that the risk of false-absences is highest for species that are poorly detectable, low in abundance, and with short flight periods. Analysis with open population binomial N-mixture models could improve estimates of abundance and distribution for rare species of conservation interest, while providing a powerful method for assessing butterfly phenology, abundance, and behavior using counts from Pollard walks, but require more intensive sampling than conventional monitoring schemes. [ABSTRACT FROM AUTHOR]

Protecting wildlife within areas of resource extraction often involves reducing habitat fragmentation. In Canada, protecting threatened woodland caribou (Rangifer taranduscaribou (Gmelin, 1788)) populations requires preserving large areas of intact forest habitat, with some restrictions on industrial forestry activities. We present a linear programming model that assesses the trade-off between achieving an objective of habitat protection for caribou populations while maintaining desired levels of harvest in forest landscapes. The habitat-protection objective maximizes the amount of connected habitat that is accessible by caribou, and the forestry objective maximizes net revenues from timber harvest subject to even harvest flow, a harvest target, and environmental sustainability constraints. We applied the model to explore the habitat protection and harvesting scenarios in the Cold Lake caribou range, a 6726 km2 area of prime caribou habitat in Alberta, Canada. We evaluated harvest scenarios ranging from 0.1 Mm3·year–1 to maximum sustainable harvest levels over 0.7 Mm3·year–1 and assessed the impact of habitat protection measures on timber supply costs. Protecting caribou habitat by deferring or reallocating harvest increases the timber unit cost by Can$1.1–2.0 m–3. However, this impact can be partially mediated by extending the harvest to areas of oil and gas extraction to offset forgone harvest in areas of prime caribou habitat. [ABSTRACT FROM AUTHOR]

Climate change will drive significant changes in vegetation cover and also impact efforts to restore ecosystems that have been disturbed by human activities. Bitumen mining in the Alberta oil sands region of western Canada requires reclamation to "equivalent land capability," implying establishment of vegetation similar to undisturbed boreal ecosystems. However, there is consensus that this region will be exposed to relatively severe climate warming, causing increased occurrence of drought and wildfire, which threaten the persistence of both natural and reclaimed ecosystems. We used a landscape model, LANDIS‐II, to simulate plant responses to climate change and disturbances, forecasting changes to boreal forests within the oil sands region. Under the most severe climate forcing scenarios (representative concentration pathway [RCP] 8.5) the model projected substantial decreases in forest biomass, with the future forest being dominated by drought‐ and fire‐tolerant species characteristic of parkland or prairie ecosystems. In contrast, less extreme climate forcing scenarios (RCPs 2.6 and 4.5) had relatively minor effects on forest composition and biomass with boreal conifers continuing to dominate the landscape. If the climate continues to change along a trajectory similar to those simulated by climate models for the RCP 8.5 forcing scenario, current reclamation goals to reestablish spruce‐dominated boreal forest will likely be difficult to achieve. Results from scenario modeling studies such as ours, and continued monitoring of change in the boreal forest, will help inform reclamation practices, which could include establishment of species better adapted to warmer and drier conditions. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Field Ornithology is the property of Resilience Alliance and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Anthropogenic disturbance can negatively impact animal populations and alter the behaviour of individuals. Disturbance associated with the energy sector has been increasing in the boreal forest of northern Alberta. Disturbances associated with the oil and gas industry vary in the infrastructure present and sensory stimuli generated. Two common types are compressor stations and roads. It is important to assess population consequences of disturbance on small mammals because they serve as prey, predators, and seed–spore dispersers in the terrestrial ecosystems that they inhabit. To test the effects of disturbance from the energy sector on the abundance and activity of small mammals, we used mark–recapture methods and live-trapped in forested areas with one side adjacent to a clearing with industrial infrastructure present (road or compressor station) or absent (control sites). We found no difference in abundance or activity of deer mice (Peromyscus maniculatus (Wagner, 1845)) and southern red-backed voles (Myodes gapperi (Vigors, 1830)) between sites and did not detect an edge effect on abundance within sites, regardless of the presence of industrial infrastructure. Our results suggest minimal effects of industrial disturbance on the abundance and activity of these species, and the infrastructure and sensory stimuli generated are unlikely to be key drivers of their population dynamics or behaviour. [ABSTRACT FROM AUTHOR]

Highlights • Mesostigmatid and oribatid mite indicated multiple disturbance types. • Coarser taxonomic ranks as sufficient as species-level identification to indicate disturbance. • Using coarser taxonomic ranks will ease the identification burden for taxonomists. Abstract Soil systems provide numerous ecosystem services but are often degraded due to anthropogenic and natural disturbances. Invertebrates can be used as biological indicators to provide information on soil health. Mites (Arachnida: Acariformes, Parasitiformes) constitute the majority of invertebrates in soil; however, their small size and diversity make them a challenging group to identify. Identification to levels coarser than species (e.g., genus, family) can alleviate some of the taxonomic difficulties. Here we test whether two groups of soil mites, Mesostigmata and Oribatida, can indicate three disturbance types (fire, forest harvest and linear features such as seismic lines and roads) in the boreal forest in northern Alberta. We assessed this at three taxonomic levels: species, genus and family. Samples were collected by the Alberta Biodiversity Monitoring Institute from 2010 to 2015 from across Alberta. We paired disturbed sites with nearby undisturbed sites while minimizing habitat and temporal differences (N pairs: fire = 13, harvest = 11, linear = 7). Mesostigmata were separated into two size categories, large only (>300 μm) and with small included (all mites > 50 μm), while oribatid were analyzed only with individuals > 300 μm. We used ANOVAs and PERMANOVAs to determine whether species richness, Shannon-Wiener diversity and assemblage structure differed significantly between disturbed and undisturbed sites. Compared to undisturbed habitats, we found that richness and diversity of Mesostigmata > 50 μm were lower with fire disturbance at all three taxonomic levels; similarly, richness and diversity of Oribatida were lower with fire and harvest at all three taxonomic levels and richness was lower for linear disturbance at family-level. Assemblage structure of Mesostigmata > 50 μm indicated fire and linear disturbance at all three taxonomic levels, while that of Mesostigmata > 300 μm indicated all three-disturbance types at species-level, and harvest disturbance at genus and family. Assemblage structure of Oribatida indicated fire disturbance at all three taxonomic levels, and linear disturbance at genus and family. Our analyses showed that mesostigmatid and oribatid mites can indicate disturbance when identified to ranks coarser than species suggests that labour-intensive species-level identifications may not always be required for bioindicator studies using soil mites. The generality of these findings should be assessed in different regions and with different disturbances. [ABSTRACT FROM AUTHOR]

Freely-available satellite data streams and the ability to process these data on cloud-computing platforms such as Google Earth Engine have made frequent, large-scale landcover mapping at high resolution a real possibility. In this paper we apply these technologies, along with machine learning, to the mapping of peatlands–a landcover class that is critical for preserving biodiversity, helping to address climate change impacts, and providing ecosystem services, e.g., carbon storage–in the Boreal Forest Natural Region of Alberta, Canada. We outline a data-driven, scientific framework that: compiles large amounts of Earth observation data sets (radar, optical, and LiDAR); examines the extracted variables for suitability in peatland modelling; optimizes model parameterization; and finally, predicts peatland occurrence across a large boreal area (397, 958 km2) of Alberta at 10 m spatial resolution (equalling 3.9 billion pixels across Alberta). The resulting peatland occurrence model shows an accuracy of 87% and a kappa statistic of 0.57 when compared to our validation data set. Differentiating peatlands from mineral wetlands achieved an accuracy of 69% and kappa statistic of 0.37. This data-driven approach is applicable at large geopolitical scales (e.g., provincial, national) for wetland and landcover inventories that support long-term, responsible resource management. [ABSTRACT FROM AUTHOR]

While there is no denying that oil sands development in the Athabasca Oil Sands Region (AOSR) has large impacts upon the habitat it disturbs, developers are legally required to return this land to “an equivalent land capability.” While still early in the process of reclamation, land undergoing reclamation offers an opportunity to study factors influencing reclamation success, as well as how reclaimed ecosystems function. As such, an Early Successional Wildlife Dynamics (ESWD) program was created to study how wildlife return to and use reclaimed upland boreal habitat in the AOSR. Wildlife data comprising 182 taxa of mammals, birds, and amphibians, collected between 2011 and 2017 and from five oil sands leases, were compared from multiple habitat types (burned [BRN], cleared [CLR], compensation lakes [COMP], logged [LOG], mature forest [MF], and reclaimed sites [REC]). Overall, similarity of wildlife communities in REC and MF plots varied greatly, even at 33 years since reclamation (31–62% with an average of 52%). However, an average community similarity of 52% so early in the successional process suggests that current reclamation efforts are progressing towards increased similarity compared to mature forest plots. Conversely, our data suggest that REC plots are recovering differently than plots impacted by natural (BRN) or other anthropogenic disturbances (LOG), which is likely due to differences associated with soil reconstruction and development on reclaimed plots. Regardless of the developmental trajectory of reclaimed habitats, progression towards increased wildlife community similarity at REC and MF plots is apparent in our data. While there is no expectation that reclaimed upland habitats will resemble or function identically to naturally occurring boreal forest, the degree of similarity observed in our study suggests that comparable ecological functionality is possible, increasing the probability that oil sands operators will be able to fulfill their regulatory requirements and duty to reclaim regarding wildlife and wildlife habitat. [ABSTRACT FROM AUTHOR]

Ecological processes driving tree success in the early stages of succession are complex and often poorly understood, involving direct and indirect relationships among multiple agents modulated by legacies. Reclamation areas of open-pit mines provide a unique opportunity to study these relationships, as these sites are often homogeneous and have few ecological legacies. Our study evaluated the early performance of three boreal tree species planted at different densities over a large reclaimed landscape (57 ha) in northern Alberta, Canada, that varied in landscape topography, surface soils, and coarse woody material. A range of soil, topographical, and seedling characteristics were measured over five growing seasons. The two surface soils had stark differences in their physical and chemical properties. Overall, seedling survival was high (> 80%) for jack pine (Pinus banksiana) and white spruce (Picea glauca) and somewhat lower (60%) for trembling aspen (Populus tremuloides). All three species grew taller in the fine-textured than in the coarse-textured soils. Linear models identified simple relationships among some of the monitored variables. To further explore more complex relationships, we built a structural equation model for jack pine growth, 2 and 5 years after planting. On coarse-textured soil, the factors controlling pine growth shifted from intrinsic factors of seedling quality in the second growing season to more complex interactions in the fifth growing season, driven by soil nutrients, water availability and colonizing vegetation. We believe these models have the potential to be useful in forest reclamation, by identifying driving factors that could be monitored to indicate reclamation success. [ABSTRACT FROM AUTHOR]

Habitat degradation associated with resource development is a major ecological concern, particularly in Canada's boreal zone where limited information on biodiversity is available. Habitat degradation can lead to reductions in biodiversity and ecosystem function, especially when drivers of variability and diversity patterns have not been identified for a region of interest. In this study, the distribution of diatom genera in the Peace-Athabasca Delta in northeastern Alberta was examined in relation to seasonal, geographic, and alkalinity gradients. Grab samples of six abiotic variables (total dissolved nitrogen, total dissolved phosphorus, dissolved iron, turbidity, pH, and specific conductance (SPC)) were taken from 12 remote wetlands over three sampling periods, and regressed against an ordination of diatom community composition to identify key environmental drivers of diatom community variation. Indirect gradient analysis identified two major gradients among sites. First, separation of sites among sampling periods showed successional seasonal changes in diatom community composition. Second, separation of sites from the Peace sub-delta and Birch sub-delta showed a gradient of geographic separation. Direct gradient analysis failed to explain the underlying drivers of these two gradients, but did show that alkalinity is a key driver of diatom community composition in the Embarras sub-delta, and that these sites could be particularly vulnerable to community changes associated with acidification. [ABSTRACT FROM AUTHOR]

Using tree data from permanent sample plots and climate data from the ClimateWNA model, mixed-effects height to live crown (HTC) models were developed for three boreal tree species in Alberta, Canada: trembling aspen (Populus tremuloides Michx.), lodgepole pine (Pinus contorta var. latifolia Engelm.) and white spruce (Picea glauca (Moench) Voss). Three model forms, the Wykoff model, a logistic model and an exponential model, were evaluated for each species. Tree height was the most significant predictor of HTC and was used in all models. In addition, we investigated the effects of competition and climatic variables on HTC modelling. Height-diameter ratio and either total stand basal area or basal area of coniferous trees were used as competition measures in the models. Different climate variables were evaluated, and spring degree-days below 0 °C, mean annual precipitation and summer heat-moisture index were incorporated into the aspen, lodgepole pine and white spruce models, respectively. Site index was only significant in lodgepole pine models. Residual variances were modelled as functions of tree height to account for heteroscedasticity still present in the mixed-effects models after the inclusion of random parameters. Based on model fitting and validation results as well as biological realism, the mixed-effects Wykoff models were the best for aspen and white spruce, and the mixed-effects logistic model was the best for lodgepole pine. [ABSTRACT FROM AUTHOR]

Well site development associated with oil sands exploration is common in boreal mixedwood forests of northern Alberta, Canada, and necessitates reforestation to accommodate other land uses. Little is known about the impact of soil and debris handling strategies during well site construction on long-term forest regeneration. This study addresses the impact of soil disturbance intensity, debris treatment, soil storage, and planting on the reforestation of 33 well sites reclaimed prior to 2006. Data on the survival and growth of planted white spruce (Picea glauca (Moench) Voss) and the regeneration density of deciduous trees, including trembling aspen (Populus tremuloides Michx), are presented from 2014 to 2015. The survival of planted spruce increased from 81% to 88% at well sites with a high relative to low soil disturbance. The total tree densities were lower in most treatments ( 2.69 stems m 2) than those in clear cuts (5.17 stems m-2), with the exception of root salvage areas where clear cuts had greater balsam poplar (Populus balsamifera L.) densities (2.05 stems m-2 vs. <0.71 stems m-2 on all other treatments). Aspen densities were up to five times greater at well sites with low disturbance when compared to those with high disturbance, and this was further aided by shallow mulch at low disturbance sites. Spruce growth did not respond to well site treatments. Aspen growth (diameter and height) remained similar between well site disturbance regimes; aspen exposed to high disturbance underperformed relative to low disturbance well sites and clear cut controls. With high disturbance, progressive soil piling led to increases in the density of aspen and birch (Betula papyrifera Marshall). Few long-term changes in soil were found due to well site development, with a greater soil pH in high disturbance sites compared to low disturbance sites. Overall, these results indicate that the nature of well site construction, including the extent of soil removal, soil piling, and debris treatment, may collectively alter forest re-establishment, with associated implications for forest management. [ABSTRACT FROM AUTHOR]

ABSTRACT Wolverines ( Gulo gulo) in the contiguous United States have been considered for protection under the Endangered Species Act, most recently based on the value of deep snow for the duration of the wolverine's denning season. We examined evidence for an obligate relationship between wolverines and spring snow cover using camera traps and long-term fur harvests in Alberta. The proportion of traplines that harvested ≥1 wolverine was highest in the northwest Boreal Forest (0.3), where mean wolverine harvest density increased by 75% from the 1990s to 2000s. There was no difference in percent spring snow cover on traplines with a female ( n = 81) or no female ( n = 416) wolverine harvest in the Boreal Forest. Further, all female wolverines ( n = 8) positively identified from camera traps in the Boreal Forest, including 5 lactating females, were located within townships predicted to have no spring snow cover. Long-term harvests and evidence of reproduction in areas with low amounts of spring snow cover in the Boreal Forest of northern Alberta suggest that wolverines may be more flexible in their distribution than previously assumed. © 2016 The Wildlife Society. [ABSTRACT FROM AUTHOR]

Copyright of Forestry Chronicle is the property of Canadian Institute of Forestry and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Background and aims: Understanding changes in soil N cycling with stand development is critical for forest management as tree growth is affected by soil N availability. The aim of this study was to evaluate the changes in soil N availability and loss with stand development in trembling aspen ( Populus tremuloides Michx.) and jack pine ( Pinus banksiana Lamb.) in northeastern Alberta, Canada. Methods: Soil inorganic N availability (measured as N supply rate) and foliar N chemistry (N concentration and δN) in trembling aspen stands ranged from 52 to 70 years old ( n = 7) and jack pine stands 43 to 78 years old ( n = 8) were investigated in 2008 and 2009. The relationships among the ratios of NO-N to total inorganic N (NO-N/TIN), foliar N concentration, and foliar δN with stand age were also explored by regression analyses. Results: Total inorganic N supply rates did not systematically change with stand age across stand types, soil layers and measurement periods; whereas NO-N/TIN showed a decreasing tendency with stand age, suggesting that nitrification and associated N loss potential became smaller in older stands with greater limitation in soil N availability. Foliar δN decreased with stand age from −1.7 to −4.7‰ for aspen and from −4.1 to −7.1‰ for jack pine, and there were positive correlations between foliar δN and soil NO-N/TIN, suggesting that decreased soil N loss led to less N-depletion in the inorganic N available for tree uptake in older stands. However, foliar N concentration did not significantly change with stand age, suggesting that there were other N sources such as organic N in the forest floor, in addition to the inorganic N, available for plant uptake. Conclusions: Our results suggest that soil inorganic N availability became more limited as stand age increased. In addition, the ratio of NO-N/TIN and its relationship with foliar δN indicated decreased soil N loss potential and shifted N sources with stand age in boreal forests that are typically N-limited. Our study demonstrated that declining nitrification with increasing stand age might be one of the mechanisms mediating N-limitation in the studied boreal forests. [ABSTRACT FROM AUTHOR]

Terrestrial gastropods are important decomposers, herbivores, and prey items in forest systems and constitute a poorly understood element of forest biodiversity in Canada. We sampled terrestrial gastropod assemblages in northwestern Alberta, Canada, using board traps and forest floor sampling to examine their association with forest composition, structure, and environment (forest floor depth and moisture, coarse woody debris, understory vegetation cover) in four boreal mixedwood cover types: broadleaf (deciduous) dominated (DDOM), broadleaf (deciduous) dominated with coniferous understory (DDOMU), mixed conifer and broadleaf (MX), and conifer dominated (CDOM). The highest total gastropod abundance and richness occurred in the DDOM cover type. Furthermore, DDOM assemblages accumulated species more quickly (with sampling effort) and supported more gastropod species at higher levels of dominance than found in other cover types. The mix of coniferous and broadleaved trees influenced gastropod distributions within stands; however, associations observed between gastropod species and tree species differed among cover types, suggesting complex ecological contingency. For example, conifer basal area was an important driver of gastropod assemblage in DDOM and DDOMU forests, whereas broadleaf basal area was the most important driver in the CDOM forest type. We conclude that tree species mixture at a variety of scales sustains diversity of gastropod assemblages and that this understanding is significant for conservation of this taxon on mixedwood boreal forest landscapes. [ABSTRACT FROM AUTHOR]

Investigations of biophysical changes on earth caused by anthropogenic disturbance provide governments with tools to generate sustainable development policy. Canada currently experiences one of the fastest rates of boreal forest disturbance in the world. Plans to conserve the 330 000 km2 boreal forest in the province of Alberta exist but conservation targets and schedules must be aligned with rates of forest disturbance. We explore how disturbance rate, and the accuracy with which we detect it, may affect conservation success. We performed a change detection analysis from 1992 to 2008 using Landsat and SPOT satellite image data processing. Canada's recovery strategy for boreal caribou ( Rangifer tarandus caribou) states that ≤35% of a caribou range can be either burned or within 500 m of a man-made feature for caribou to recover. Our analyses show that by 2008 78% of the boreal forest was disturbed and that, if the current rate continues, 100% would be disturbed by 2028. Alberta plans to set aside 22% for conservation in a region encompassing oil sands development to balance economic, environmental, and traditional indigenous land-use goals. Contrary to the federal caribou recovery strategy, provincial conservation plans do not consider wildfire a disturbance. Based on analyses used in the provincial plan, we apply a 250 m buffer around anthropogenic footprints. Landsat image analysis indicates that the yearly addition of disturbance is 714 km2 (0.8%). The higher resolution SPOT images show fine-scale disturbance indicating that actual disturbance was 1.28 times greater than detected by Landsat. If the SPOT image based disturbance rates continue, the 22% threshold may be exceeded within the next decade, up to 20 years earlier than indicated by Landsat-based analysis. Our results show that policies for sustainable development will likely fail if governments do not develop time frames that are grounded by accurate calculations of disturbance rates. [ABSTRACT FROM AUTHOR]

Aim It is challenging to disentangle how local habitat structure, climate, and human disturbance interplay to determine broad-scale variation of species richness. Here, we separated various measures of local forest structure and composition, abiotic factors, and human land cover that constrain species richness of bird guilds in the boreal forest. Location Boreal forest, western Canada. Methods Data on breeding birds, habitat structure, climate and human footprints in 206 sites were sampled, with each site centred on an area of 1 ha in size. The 206 sites cover a large geographical extent with a distance of c. 1000 km between the most distant sites. We modelled bird guild species richness in relation to forest structure and composition (woody plant richness, forest biomass, number of vegetation layers, canopy openness), abiotic environment (temperature, precipitation, elevation), and percentage area of human land cover. We classified bird species into different guilds based on dietary preference, habitat specialization and migratory status, and used structural equations to quantify effect strengths of predictor variables. Results We found that temperature, low levels of human land cover, woody plant richness and number of vegetation layers had strong positive correlations with overall bird species richness in the boreal forest. Moreover, local forest structure and composition showed a pronounced variation in their relationships with species richness of different guilds. Insectivores, old-growth forest specialists, forest generalists, long-distance migrants and winter residents showed strong positive correlations with woody plant richness, whereas old-growth forest specialists and winter residents were strongly related to forest biomass as well. The number of vegetation layers was positively related to species richness of most guilds, whereas the response to canopy openness was most pronounced for old-growth forest specialists and winter residents (being negatively correlated). Main conclusions In addition to climate and human disturbance, local forest structure and composition are important determinants of broad-scale variation of bird species richness in boreal forest. However, the strength and direction (positive/negative) of determinants is guild-specific, suggesting a strong functional component to community structure. [ABSTRACT FROM AUTHOR]

Increasing fragmentation of forests worldwide by timber and industrial development makes it important to understand the edge effects of common anthropogenic disturbances on forest fauna. We collected ground-active spiders along transects across the edge of logging clearcuts, gravel roads and gas pipelines in the boreal forest of Alberta, sampling on the disturbance (10 m from forest edge), and 10, 45, and 200 m into the forest. We asked whether the three disturbances were associated with edge effects on spider communities, and whether the extent of their associated edge effects were equivalent. The spider community at the edges of clearcuts was distinct from interior and on-disturbance communities 10 m into the forest from the clearcut edge, showing an edge effect of between 10 and 45 m from clearcut edges, while no edge effects were apparent at road and pipeline edges. Edge effects therefore differ at linear and non-linear openings in the boreal forest, which suggests that small linear openings may be associated with minimal edge effects compared to large polygonal forest openings. This result has important consequences for forest management, where clearcuts and other non-linear openings are likely to cause edge effects on spider communities that are between 10 and 45 m in their extent. The small size of clearcuts as practiced in the public forests of Canada, and their dense and broad application across the landscape, makes this edge effect of broad spatial significance in protecting biodiversity in managed landscapes. [ABSTRACT FROM AUTHOR]

Drawing on the traditional ecological knowledge (TEK) of the Lesser Slave Lake Cree, this paper shares understanding of how resource development has affected water, fish, forests, and wildlife as well as the well-being of Cree communities in the Lesser Slave Lake region of Alberta, Canada. In addition to descriptive observations of change, the narratives point to social-ecological thresholds or tipping points in the relationship of Cree harvesters to local lands and resources. Specifically, the study speaks to the echoing effects of ecological loss and degradation on traditional livelihood practices over the last 100 years highlighting the complexity of cumulative effects as well as the challenges of balancing resource development in the region with alternative land uses including those valued by Alberta's Aboriginal peoples. [ABSTRACT FROM AUTHOR]

Abstract: The effects of 4years of simulated nitrogen (N) and sulfur (S) depositions on gross N transformations in a boreal forest soil in the Athabasca oil sands region (AOSR) in Alberta, Canada, were investigated using the 15N pool dilution method. Gross NH4 + transformation rates in the organic layer tended to decline (P <0.10, marginal statistical significance, same below) in the order of control (CK, i.e., no N or S addition), +N (30kgNha−1 yr−1), +S (30kgSha−1 yr−1), and +NS treatments, with an opposite trend in the mineral soil. Gross NH4 + immobilization rates were generally higher than gross N mineralization rates across the treatments, suggesting that the studied soil still had potential for microbial immobilization of NH4 +, even after 4years of elevated levels of simulated N and S depositions. For both soil layers, N addition tended to increase (P <0.10) the gross nitrification and NO3 − immobilization rates. In contrast, S addition reduced (P <0.001) and increased (P <0.001) gross nitrification as well as tended (P <0.10) to reduce and increase gross NO3 − immobilization rates in the organic and mineral soils, respectively. Gross nitrification and gross NO3 − immobilization rates were tightly coupled in both soil layers. The combination of rapid NH4 + cycling, negligible net nitrification rates and the small NO3 − pool size after 4years of elevated N and S depositions observed here suggest that the risk of NO3 − leaching would be low in the studied boreal forest soil, consistent with N leaching measurements in other concurrent studies at the site that are reported elsewhere. [Copyright &y& Elsevier]

Abstract: In the boreal forest of Alberta, fire and wind often open gaps in the canopy where late-successional species can establish and over time cause a shift in the species distribution from deciduous (e.g., trembling aspen) dominated to mixedwood, to shade-tolerant conifer (e.g., white spruce) dominated stands. This study attempted to understand the change of density-dependent competition in a boreal chronosequence and the role of tree competition in affecting stand structure and mortality. Four 1-ha stem-mapped plots were established to represent a chronosequence comprised of aspen dominated, mixedwood, and spruce dominated stands in Alberta. Second order spatial point-pattern analysis using Ripley''s K(t) function showed that intraspecific competition is a prevailing force causing conspecific tree mortality and thus shaping the stand structure. The results of bivariate K(t) function analysis did not reveal sufficient evidence of interspecific competition. This suggested that competitive interaction among heterospecific trees was not strong enough to cause significant tree mortality, but the analysis of marked correlation function revealed that interspecific competition could have a negative impact on tree growth. This study highlights the importance of density-dependent competition in understanding stand dynamics of boreal forests over succession. [Copyright &y& Elsevier]

Fens are important components of Canada’s western boreal forests, occupying about 63% of the total peatland area and storing about 65% of the peatland carbon. Rich fens, dominated by true moss-dominated ground layers, make up more than half of the fens in the region. We studied organic matter accumulation in three rich fens that represent the diversity in structural types. We used in situ decomposition socks, a new method that examines actual decomposition throughout the upper peat profile over an extended period of time. We coupled our carbon loss data with macrofossil analyses and dated peat profiles using 210Pb. Across the three rich fens and in the top 39 cm of the peat column, dry mass increases on average 3.1 times. From our dry mass loss measurements, we calculate that annual mass loss from the top 39 cm varies from 0.52 to 1.08 kg m2. Vertical accumulation during the past 50 years has varied from 16 to 32 cm and during these 50 years, organic matter accumulation has averaged 174 g m−2 y−1 compared to 527 g m2 y−1 dry mass loss, with additional mass losses of 306 g m2 y−1 from peat between 50 and 150 years of age. Organic matter accumulation from our rich fens compares well with literature values from boreal bogs, whereas peat bulk densities increase about three times within the uppermost 40 cm, much more than in bogs. Hence, rich fens accumulate peat not because the plant material is especially hard to decompose, is acidic, or has the catotelm especially close to the surface, but because dense, rapidly produced inputs outweigh the relatively rapid decomposition process of the upper peat column. [ABSTRACT FROM AUTHOR]

1. Roads are an important conduit for the spread of invasive species. Road age is a key factor that could influence the susceptibility of roads to invasion as older roads are typically subject to higher cumulative levels of human disturbance and propagule pressure than younger roads. We investigated the effects of road age on the spread of non-native earthworms, which act as ecosystem engineers. 2. We sampled earthworms and habitat variables at 98 roads in the boreal forest of Alberta, Canada, to determine the influence of road age on non-native earthworm occurrence at the landscape level. The extent and rate of local spread were also assessed at seven sites adjacent to old and young roads. Generalized estimating equations and zero-inflated negative binomial regression were used to analyze landscape- and local-level results, respectively. We used our models to create maps that predict the current and potential future extent of earthworms in north-eastern Alberta. 3. Probability of earthworm occurrence and extent of spread increased as road age increased. Areas closer to agriculture and towards the south and west of our study area were also significantly more likely to be invaded by earthworms. 4. Our spread model indicated that approximately 9% of the boreal forest of north-eastern Alberta is likely invaded by earthworms currently. This is projected to increase to 49% of suitable forest habitat over the next 50 years as human development intensifies in this region. 5. Synthesis and applications. Although the effects of roads and linear features are commonly investigated in relation to native species, our results emphasize the importance of considering the impacts of linear feature creation on the spread of invasive species. We demonstrate that road age in particular can be an important factor affecting the spread of invasive species. In the boreal forest, reducing the number of roads being constructed, restricting traffic, and reclaiming temporary roads will be critical to reduce the future extent of earthworm invasions. [ABSTRACT FROM AUTHOR]

There is a critical need for spatially and temporally extensive information on the trophic status of lakes to assist in scientifically sound forest management decisions. To meet this need, this study examined the utility of Landsat TM imagery in deriving indicators of trophic status in remote and relatively undisturbed lakes on the Boreal Plain of northern Alberta. Based on data collected during a survey of lakes in 2001, normalized exoatmospheric reflectance values of the red band explained 68, 82, and 47% of the variance in chlorophyll a, turbidity, and Secchi disk depth, respectively. To understand the natural variation in trophic status in the lakes, we applied the linear regression equations to images collected during late summer (i.e., August) for 18 out of 20 years from 1984 to 2003 and performed a two-way analysis of variance to decompose the total variation into space, time, and space×time interaction factors. We found that temporal factors accounted for 10% and spatial factors accounted for 50% of the total variation in trophic status, with a minimum of 10 years and 20 lakes needed to reach stability in the contributions of these factors. This study suggests that regional factors that are external to the lake explained the majority (60%) of the variation in trophic status of the lakes. [Copyright &y& Elsevier]

Mountain pine beetle (MPB) is the most serious pest of lodgepole pine in western Canada, and it is predicted to spread into boreal jack pine within the next few years. Colonization of host trees by MPB-associated blue-stain fungi appears to be required for successful beetle reproduction. Three species of blue-stain fungi, Grosmannia clavigera (Robinson-Jeffery and Davidson) Zipfel, de Beer, and Wingfield (≡ Ophiostoma clavigerum (Robinson-Jeffery and Davidson) Harrington), Ophiostoma montium (Rumbold) von Arx, and Leptographium longiclavatum Lee, Kim, and Breuil, are associated with MPB in Alberta. In inoculation experiments, all three fungi caused lesions on lodgepole pine, jack pine, and their hybrids. On average, lesions were longer on jack pine and hybrids than on lodgepole pine, suggesting that fungal development will not be a barrier to MPB success in these trees. Differences in lesion length caused by the three fungal species were minimal, with significant differences observed only on hybrid pine and between O. montium and the other fungal treatments. On average, lesions caused by combinations of the three fungi (pair-wise and all together) did not differ significantly in length from those caused by the fungi singly, and none of the fungal species competitively excluded any of the others. These observations suggest that all three species are pathogenic to boreal pines and that the virulence of all three species is comparable. [ABSTRACT FROM AUTHOR]

Forty-one remnants of the aspen-dominated upland forest in three subregions of the dry boreal mixed-wood in Alberta were studied to determine effects of fragment size and shape on native and alien plant species richness and abundance in agro-environments. The percent cover of all vascular plant species was visually estimated in 5 m diameter circular plots along transects that covered the length and the width of each fragment. A subset of 12 of the largest fragments (>900 m2) that had distinct interiors (portions of the fragment >15 m from any edge) was used to measure edge effects on the vegetation. Regression analyses revealed significant positive relationships between species richness and area regardless of the subregion. Species richness stabilized in fragments that were larger than 11 ha. Edges did not affect shrub species richness and only affected herbaceous species richness on west- and south-facing aspects. Shrub abundance decreased and herb abundance increased up to 20 m from the edges regardless of orientation. Edges did not support a different suite of species than interiors, although several species occurred more frequently in the interior than along the edges. Alien species richness and abundance reached their highest values between 5 and 15 m from the edge, and some of those species could be found up to 40 m from the edge. Although larger fragments generally supported more alien species than smaller fragments, the smallest fragments had the greatest number of species per metre squared. Results from this study indicated that it would be preferable to conserve larger woodlots rather then several smaller woodlots on the landscape. [ABSTRACT FROM AUTHOR]

Succession of stream ponds mediated by beaver (Castor canadensis) damming and foraging in riparian zones may contribute to changes in amphibian populations. Our study examined the use of beaver ponds by the wood frog (Rana sylvatica) in a network of boreal streams in west-central Alberta, Canada. We quantified relations between breeding populations of wood frogs estimated from call surveys and pond age and riparian canopy cover, and we compared an index of juvenile recruitment to metamorphosis estimated with pitfall trap captures between new (<10 yr) and old (>25 yr) beaver ponds. We also conducted an in-pond enclosure experiment to determine if differences in physicochemical conditions of new versus old ponds influenced larval performance. Regression and Akaike's Information Criterion model averaging indicated that both density and calling intensity of male wood frogs at beaver ponds had a negative relationship with percent riparian canopy cover and had a positive relationship with pond age. The best a priori statistical models, however, included riparian canopy cover rather than pond age as a significant covariate. Old ponds had reduced riparian canopy and greater abundance of submergent vegetation, thermal degree-days, and dissolved oxygen concentrations compared to newly formed ponds. While survival of larval wood frogs in enclosures did not differ between pond age classes, growth and development rates in old ponds were greater than in new ponds. In addition to warmer water in old ponds, results from a laboratory experiment suggest that higher concentrations of dissolved oxygen characteristic of old ponds can enhance larval growth rates. Older beaver ponds may support more breeding wood frogs due to adult selection for open-canopy ponds and the associated larval environments favourable for high rates of juvenile recruitment. Forest management that protects beaver and their food supplies may also promote healthy populations of boreal amphibians. [ABSTRACT FROM AUTHOR]

Lightning fire is the dominant natural disturbance of the western mixedwood boreal forest of North America. We quantified the independent effects of weather and forest composition on lightning fire initiation (a detected and recorded fire start) patterns in Alberta, Canada, to demonstrate how these biotic and abiotic components contribute to ecosystem dynamics in the mixedwood boreal forest. We used logistic regression to describe variation in annual initiation occurrence among 10 000-ha landscape units (voxels) covering a 9 million-ha study region over 11 years. At a voxel scale, forest composition explained more variation in annual initiation than did weather indices. Initiations occurred more frequently in landscapes with more conifer fuels (Picea spp.), and less in aspen-dominated (Populus spp.) ones. Initiations were less frequent in landscapes that had recently burned. Variation in initiation was also influenced by joint weather—lightning indices, but to a lesser degree. For each voxel, these indices quantified the number of days in the fire season when moisture levels were low and lightning was detected. Regional indices of fire weather severity explained substantial interannual variation of initiation, and the effect of forest composition was stronger in years with more severe fire weather. Our study is a conclusive demonstration of biotic and abiotic regulation of lightning fire initiation in the mixedwood boreal forest. The independent effects of forest composition emphasize that vegetation feedbacks strongly regulate disturbance dynamics in the region. [ABSTRACT FROM AUTHOR]

Although the American Marten (Martes americana) is found in most forest regions of Alberta, little is known about its choice of winter habitats. This study investigated winter habitat use by American Marten in Weyerhaeuser's Grande Prairie Forest Management Area (FMA) using snowtracking along 128.2 km of seismic lines inventoried in winters 1999, 2002, and 2005 with snowmobiles. American Marten tracks (n = 44) occurred significantly less frequently than expected (P <0.001) in immature/young pole stands, but more frequently than expected (P < 0.02) in mature/old growth mixedwood stands. American Martens apparently used young forests, and mature/old coniferous and deciduous stands, according to their availability. Forest development plans should be developed locally to retain late successional forests that meet the winter habitat requirements of American Marten. [ABSTRACT FROM AUTHOR]

Conservation of biological diversity under the natural disturbance model of boreal forest management relies on the assumption that natural mosaics of stand composition and structure can be adequately recreated through forest management activities. Maintaining compositional and structural features that provide adequate habitat for species within managed stands is the basis of coarse-filter conservation strategies. Here we test the effect of stand composition and stand structure on the epigaeic arthropod fauna from four boreal mixedwood cover types in western Canada. We observed differences in epigaeic community composition and species-specific associations among each of the four cover types. Differences in the carabid fauna between cover types were defined by relative abundance of carabid species associated specifically with moss cover, forb cover, and of coarse woody material, rather than unique, stand-specific species compositions of the overstory. Cover-type differences were less apparent among the comparatively species-rich spider assemblages largely because of their low abundance in undisturbed stands. For the effective conservation of all species, our results suggest that coarse-filter management of mixedwood boreal forests must incorporate structural features beyond overstory canopy composition. Our analyses also suggest that activities directed at managing the amount of coarse woody material on the ground and understory plant composition, perhaps through variable retention harvesting, is a logical first step. [ABSTRACT FROM AUTHOR]

Reports on changes in terrestrial vertebrate communities from pre- to post-harvest in experimentally created buffer strips (20, 100, 200, and 800 m wide) in a boreal mixedwood forest in Alberta, Canada. Focus on the utility of forested buffer strips as reserves for forest species in managed landscapes; Observations on abundance of small mammals, amphibians, and forest-dependent bird species; Conclusion that 20?100 m buffers would not serve as reserves for forest songbirds in managed landscapes.

Borrow pits, dug by industry to provide substrate for infrastructure such as roads and well sites, are prevalent throughout the boreal forest of western Canada yet little is known about their use by wildlife. During field surveys in Rainbow Lake, Alberta, we found that beavers (Castor canadensis) used inundated borrow pits extensively for foraging and over wintering, suggesting that borrow pits increase beaver populations above their natural carrying capacity in industrial landscapes. We visited a random sample of 90 borrow pits in the field and categorized them as having active beaver lodges with caches (n = 16), inactive lodges (n = 13), cutting (n = 29), no activity (n = 13), or as not inundated or not a borrow pit (n = 19). We then used this sample to model where beavers established lodges versus where they were inactive or were only cutting. We found that borrow pits with active lodges had unique characteristics from other pits in our sample and were closer to streams, marshes, and swamps and had greater vegetation concealment from roads. These models can be used by managers to develop methods for increasing or decreasing the abundance of beavers living at borrow pits. Wildlife managers might want to use borrow pits to increase beaver abundance because of the positive effects beavers can have on ecosystems and because beavers are an important source of food for boreal carnivores. For example, we found that wolverines (Gulo gulo) used borrow pits as hunting grounds for beavers and one wolverine denned within a beaver lodge at a borrow pit. Conversely, managers might want to reduce beaver populations living at borrow pits because of the damage that beavers can cause to infrastructure and because subsidized beaver populations might alter predator-prey dynamics. To accomplish this, we suggest reducing available vegetation around borrow pits, isolating new borrow pits from natural beaver habitats, digging borrow pits where there is less chance of having surface water, filling in borrow pits with substrate, or not creating borrow pits and using a centralized gravel pit or mine for substrate. • We found beaver activity at the majority of borrow pits in Rainbow Lake, Alberta. • We modeled habitats associated with borrow pits where beavers established lodges versus other beaver activities. • Active beaver colonies were closer to marshes, swamps, and streams and had a tall vegetation buffer between the borrow pit and road. • Beavers occupying borrow pits subsidized prey for wolverines and other carnivores. [ABSTRACT FROM AUTHOR]

• Context for pipeline corridors as potential ecological sinks for wildlife populations. • Quantitative analysis of plant taxa foraged by woodland caribou and grizzly bear. • Species composition and cover varied between pipelines versus adjacent forest. • High cover of graminoids on pipeline corridors as compared to adjacent forest. • Prioritizing ecosites within caribou ranges may be a beneficial restoration strategy. The construction of pipeline rights-of-way (ROWs, hereafter 'pipeline') involves mechanical site clearing, which impacts soil and ground cover vegetation and has implications for forage availability and predation risk for threatened wildlife, including woodland caribou (Rangifer tarandus) and grizzly bear (Ursus arctos). However, there has been no quantitative evaluation of vegetation communities on open pipelines as compared to the adjacent intact forest. We compared the cover of ground vegetation by vegetation type, and the cover and composition for plant taxa known for their importance as woodland caribou and grizzly bear forage, between plots located on pipeline corridors, near the edge of the pipeline corridor, and in the adjacent undisturbed forest across six different boreal forest ecosite types in west-central and north-western Alberta, Canada. Pipeline corridors were characterized by higher total ground vegetation cover, and cover of low shrubs, lichens, bryophyte and of targeted forage species of low shrubs, bryophytes, and lichens. In contrast, pipelines had higher graminoid cover and cover of target forage species of tall shrubs and graminoids, as compared to adjacent forest. Despite the substantive differences in cover and composition of ground vegetation among the ecosite types, differences between pipelines and the adjacent forest were quite consistent, with a few exceptions. For instance, forb cover was higher in the adjacent forest compared with pipelines in shrubby ecosite types, but was similar across plot locations in other ecosites. Species composition also varied among ecosites and differed between the adjacent forest and on pipelines; with pipelines dominated by graminoids, particularly Carex species. Our results demonstrate that pipelines influence ground vegetation communities, and cover and composition of wildlife forage species, across the boreal forest landscapes of Alberta; we suggest this results in pipelines being a potential ecological sink for wildlife populations, including threatened caribou. To ensure pipelines can recover, restoration strategies that promote natural recovery or purposeful re-planting may be required to accelerate forest re-establishment and put inactive pipeline corridors within caribou ranges on a recovery trajectory. Our results suggest that ecosites can be used to prioritize pipelines where restoration or management actions may be the most beneficial. [ABSTRACT FROM AUTHOR]

Forest canopy openings are a key element of forest structure, influencing a host of ecological dynamics. Light detection and ranging (LiDAR) is the de-facto standard for measuring three-dimensional forest structure, but digital aerial photogrammetry (DAP) has emerged as a viable and economical alternative. We compared the performance of LiDAR and DAP data for characterizing canopy openings and no-openings across a 1-km2 expanse of boreal forest in northern Alberta, Canada. Structural openings in canopy cover were delineated using three canopy height model (CHM) alternatives, from (i) LiDAR, (ii) DAP, and (iii) a LiDAR/DAP hybrid. From a point-based detectability perspective, the LiDAR CHM produced the best results (87% overall accuracy), followed by the hybrid and DAP models (47% and 46%, respectively). The hybrid and DAP CHMs experienced large errors of omission (9–53%), particularly with small openings up to 20m2, which are an important element of boreal forest structure. By missing these, DAP and hybrid datasets substantially under-reported the total area of openings across our site (152,470 m2 and 159,848 m2, respectively) compared to LiDAR (245,920 m2). Our results illustrate DAP's sensitivity to occlusions, mismatched tie points, and other optical challenges inherent to using structure-from-motion workflows in complex forest scenes. These under-documented constraints currently limit the technology's capacity to fully characterize canopy structure. For now, we recommend that operational use of DAP in forests be limited to mapping large canopy openings, and area-based attributes that are well-documented in the literature. [ABSTRACT FROM AUTHOR]

Stressors created by multiple resource industries can result in cumulative effects over time and space. Many studies have evaluated single stressors and assumed that cumulative effects can be understood by adding stressors together. However, there is growing evidence that interactive effects are important in structuring biological communities. We evaluated whether the effects of multiple stressors in the boreal forest (linear features, energy, forestry) combine additively or interactively by testing a candidate model set of 12 cumulative effects models of abundance for 27 landbird species. We fitted paired additive and interactive Generalized Additive Models and examined model predictions in the Athabasca Oil Sands Area of Alberta, Canada, and a theoretical no‐disturbance version of the study area. Of the 27 species examined, an additive disturbance model was the best for nine species, while an interactive disturbance model was the best for 11 species. In the current study area, disturbance models predicted strong increases in abundance for species associated with deciduous forest and open habitats (winning species) and moderate decreases for species associated with conifer forest (losing species). We found a 15% change in landbird community composition between the current study area, with 8.4% disturbance, and the theoretical no‐disturbance study area. Complex synergistic and antagonistic interactions among stressors were observed for 39% of landbird species, with the majority of interactions observed being synergistic. Stressors with relatively small disturbance areas, such as narrow linear disturbances, frequently interacted with other stressors to affect species' responses, and energy sector stressors often had additive or interactive effects with forestry stressors. Interactive cumulative effects from multiple sectors will make it increasingly difficult for industry and land managers to manage impacts unless interactions among stressors are incorporated into cumulative effects assessments and regional land use planning processes. [ABSTRACT FROM AUTHOR]

Discusses the proceedings of an international conference entitled The Role of Boreal Forests and Forestry in the Global Carbon Budget was held in Edmonton, Alberta, Canada, from 8 to 12 May, 2000 to examine the present state of understanding of this subject, hosted by the Canadian Forest Service, the conference attracted nearly 300 scientists, forest managers, and policy advisors from around. Themes of the conference, including spectrum of research, broken into four themes, including boreal forest carbon budgets, monitoring and measuring boreal forest carbon fluxes and stocks, forestry practices for carbon management and social and economic issues, including implications of the Kyoto Protocol. Publications which capture the current scientific understanding of the contribution of boreal forests and forestry to the global carbon cycle, as presented at this conference, was captured in a series of publications.

Water quality, environment, agricultural land use, waterfowl, and fish community data were collected from wetlands in four landscapes (West Peace Lowlands, East Peace Lowlands, West Central, and East Central) in the Boreal Transition Zone (BTZ) of Alberta (AB) and with one landscape in British Columbia (East Peace Lowlands, BC) during May and August over three years (2005-2007). This data set is unique in that it provides comprehensive water quality sampling, habitat conditions, and associated breeding and molting waterfowl data over a three-year period, which includes a drought year. Land use in the BTZ has rapidly changed with at least 73% of the BTZ. particularly in Saskatchewan, AB. being converted from forest to agriculture since the early 20th century. The BTZ has experienced a drying trend over the past 60 years with the lowest cumulative effective precipitation since 1943 with a --2323-mm precipitation deficit recorded in 2006. A total of 723 and 489 wetlands were surveyed for waterfowl abundance during the breeding and molting seasons, respectively. A subset of 214 and 213 wetlands in May and August, respectively, was further sampled for habitat, limnology, and agricultural encroachment surrounding the wetland. A subset of 25 wetlands was sampled in 2006 for fish abundance data. This data set has been used in several papers in assessing the impact of drought and agricultural impact on water quality and wetland conditions, as well as drought and land use impacts on habitat associations between breeding and molting waterfowl and wetland condition. [ABSTRACT FROM AUTHOR]