36 Works

Data from: Linking resource availability and heterogeneity to understorey species diversity through succession in boreal forest of Canada

Praveen Kumar, H.Y.H. Chen, S.C Thomas, Chander Shahi, Sean C. Thomas & Han Y. H. Chen
Understorey vegetation hosts the majority of species diversity and contributes greatly to ecosystem functioning in natural systems. Although patterns of understorey abundance, species diversity and composition associated with forest stand development are well researched, mechanisms driving these patterns remain largely speculative. We sampled fire origin stands of varying stand ages and overstorey compositions on mesic sites of the boreal forest of Canada and used structural equation modeling (SEM) to link time since fire (stand age),...

Database from forest inventory of the different states and provinces of western North America

Yassine Messaoud
The climate variables effect on tree growth in boreal and temperate forests has received increased interest in the global context of climate change. However, most studies are often limited to local or regional scales and involved a few tree species. Here, sixteen tree species across western North America were used to investigate tree response to climate change at the species range scale. Forest inventory databases from 36,944 stands established between1600 and 1968 throughout western Canada...

Thermal stratification and fish thermal preference explain vertical eDNA distributions in lakes

Joanne Littlefair, Lee Hrenchuk, Paul Blanchfield, Michael Rennie & Melania Cristescu
Significant advances have been made towards surveying animal and plant communities using DNA isolated from environmental samples. Despite rapid progress, we lack a comprehensive understanding of the “ecology” of environmental DNA (eDNA), particularly its temporal and spatial distribution and how this is shaped by abiotic and biotic processes. Here, we tested how seasonal variation in thermal stratification and animal habitat preferences influence the distribution of eDNA in lakes. We sampled eDNA depth profiles of five...

Data from: Global pattern and drivers of nitrogen saturation threshold of grassland productivity

Yunfeng Peng, Han Chen, Yuanhe Yang & Han Y.H. Chen
Ecosystem productivity usually exhibits first increase and then saturated response to increasing nitrogen (N) additions, yet the broad-scale pattern and potential drivers of the N saturation threshold are little investigated. By synthesizing N addition experiments with at least four N-input levels from the global grasslands, we applied the quadratic-plus-plateau model to fit the aboveground net primary productivity (ANPP)-N rate relationship, and estimated the saturation threshold for N rate (critical N rate, NCR) and maximum ANPP...

Data from: Above- and belowground drivers of intraspecific trait variability across subcontinental gradients for five ubiquitous forest plants in North America

Isabelle Aubin, Françoise Cardou, Alison Munson, Madhur Anand, André Arsenault, F. Wayne Bell, Yves Bergeron, Isabelle Boulangeat, Sylvain Delagrange, Nicole J. Fenton, Dominique Gravel, François Hébert, Jill Johnstone, S. Ellen Macdonald, Azim Mallik, Anne C.S. McIntosh, Jennie R. McLaren, Christian Messier, Dave Morris, Bill Shipley, Luc Sirois, Nelson Thiffault, Laura Boisvert-Marsh & Bright B. Kumordzi
Intraspecific trait variability (ITV) provides the material for species adaptation to environmental changes. To advance our understanding of how ITV can contribute to species adaptation to a wide range of environmental conditions, we studied five widespread understory forest species exposed to both continental-scale climate gradients, and local soil and disturbance gradients. We investigated the environmental drivers of between-site leaf and root trait variation, and tested whether higher between-site ITV was associated with increased trait sensitivity...

Data from: Functionally diverse tree stands reduce herbaceous diversity and productivity via canopy packing

Liting Zheng, Y. H. Han Chen, Yann Hautier, Difeng Bao, Mingshan Xu, Baiyu Yang, Zhao Zhao, Li Zhang & Enrong Yan
1. There is extensive experimental evidence for the importance of biodiversity in sustaining ecosystem functioning. However, such experiments typically prevent immigration by continuously removing non-target species, thereby questioning the generality of these findings to real-world ecosystems. This is particularly true in forest ecosystems where understorey herbaceous species are key biodiversity components but are usually weeded in tree diversity experiments. Consequently, little is known about how tree diversity influences the natural dynamics of understorey herbaceous layers....

Data from: Isodars unveil asymmetric effects on habitat use caused by competition between two endangered species

Rocío Tarjuelo, Juan Traba, Manuel B. Morales & Douglas W. Morris
In order for competing species to coexist, segregation on some ecological niche component is required and is often mediated by differential habitat use. When unequal competitors are involved, the dominant species tends to displace the subordinate one to its less preferred habitat. Here, we use habitat isodars, an approach which reflects evolutionary stable strategies of habitat selection, to evaluate whether interspecific competition between two competing species with distinct habitat preferences, the little bustard Tetrax tetrax...

Forest soil acidification consistently reduces litter decomposition irrespective of nutrient availability and litter type

Ying Shen, Tian Dashuan, Hou Jihua, Wang Jinsong, Zhang Ruiyang, Li Zhaolei, Chen Xinli, Wei Xuefeng, Zhang Xinyu, He Yicheng & Niu Shuli
Nitrogen (N), phosphorus (P), and acid deposition are co-occurring in many ecosystems, likely with complex interactive effects on litter decomposition. Few studies have been conducted to distinguish the interactive effects of these three factors on forest litter decomposition. Thus, we performed a 5-year litter decomposition experiment with N, P, acid addition in a temperate forest of Changbai Mountain in China, including four litter types from Pinus koraiensis, Quercus mongolica, Tilia amurensis and their mixtures. Our...

Isotopic evidence for long-distance connections of the AD thirteenth century Promontory caves occupants

Jessica Metcalfe, John Ives, Sabrina Shirazi, Kevin Gilmore, Jennifer Hallson, Fiona Brock, Bonnie Clark & Beth Shapiro
The Promontory caves (Utah) and Franktown Cave (Colorado) contain high-fidelity records of short-term occupations by groups with material culture connections to the Subarctic/Northern Plains. This research uses Promontory and Franktown bison dung, hair, hide, and bone collagen to establish local baseline carbon isotopic variability and identify leather from a distant source. The ankle wrap of one Promontory Cave 1 moccasin had a δ13C value that indicates a substantial C4 component to the animal’s diet, unlike...

Interactive effects of global change factors on terrestrial net primary productivity are treatment length- and intensity-dependent

Zilong Ma, Scott Chang, Han Chen & Yongchun Li
1. Individual effects of co‐occurring global change factors on net primary productivity (NPP) have been widely studied; however, their interactive effects remain highly debated. 2. Here, we conducted a global meta‐analysis based on 919 multifactor observations from 120 published studies to examine the interactive effects on NPP of global change factors including elevated [CO2], warming, nitrogen addition, irrigation, drought, and changes in species diversity. 3. On average, of the factors studied, six pairs of factors...

Abundance of Anolis bicaorum, and niche measurements of plots on the island Utila, Honduras

Emma Higgins, Doreen Boyd, Tom Brown, Sarah Owen & Adam Algar
The question of what controls animal abundance has always been fundamental to ecology, but given rapid environmental change, understanding the drivers and mechanisms governing abundance is more important than ever. Here, we determine how multidimensional environments and niches interact to determine population abundance along a tropical habitat gradient. Focusing on the endemic lizard Anolis bicaorum on the island of Utila (Honduras), we evaluate direct and indirect effects of three interacting niche axes on abundance: thermal...

Ancient DNA-based sex determination of bison hide moccasins provides evidence for selective hunting strategies by Promontory Cave occupants

Sabrina Shirazi, Nasreen Broomandkhoshbacht, Jonas Oppenheimer, Jessica Metcalfe, Rob Found, John Ives & Beth Shapiro
The thirteenth-century human occupants of Promontory Cave, Utah, distinguished themselves from surrounding Fremont populations by being successful hunting specialists of bison in a region normally peripheral for that species. The hunters’ success is evident from the abundance of faunal remains excavated from the dry caves, which has facilitated zooarchaeological study of bison hunting strategies. The dry cave conditions also preserved hundreds of worn moccasins, which are of particular interest because of the Canadian-Subarctic style in...

Data from: Edge influence on vegetation at natural and anthropogenic edges of boreal forests in Canada and Fennoscandia

Karen A. Harper, S. Ellen Macdonald, Michael S. Mayerhofer, Shekhar R. Biswas, Per-Anders Esseen, Kristoffer Hylander, Katherine J. Stewart, Azim U. Mallik, Pierre Drapeau, Bengt-Gunnar Jonsson, Daniel Lesieur, Jari Kouki & Yves Bergeron
1. Although anthropogenic edges are an important consequence of timber harvesting, edges due to natural disturbances or landscape heterogeneity are also common. Forest edges have been well-studied in temperate and tropical forests, but less so in less productive, disturbance-adapted boreal forests. 2. We synthesized data on forest vegetation at edges of boreal forests and compared edge influence among edge types (fire, cut, lake/wetland; old vs. young), forest types (broadleaf vs. coniferous) and geographic regions. Our...

Data from: Intensive forest harvesting increases susceptibility of northern forest soils to carbon, nitrogen and phosphorus loss

Alexandra M. Hume, Han Y. H. Chen & Anthony R. Taylor
1. Understanding the impact of forest harvesting is critical to sustainable forest management, yet there remains much uncertainty regarding how harvesting affects soil carbon (C), nitrogen (N) and phosphorus (P) dynamics. 2. Here we conducted a global meta-analysis of 808 observations from 49 studies to test the effects of harvesting on the stocks and concentrations of soil C, N, and P and C:N:P ratios relative to uncut control stands. 3. With all harvesting intensities combined,...

Data from: Effects of species diversity on fine root productivity increase with stand development and associated mechanisms in a boreal forest

Zilong Ma & Han Y. H. Chen
There is a growing interest in understanding the relationship between diversity and below-ground productivity due to the critical contribution of below-ground systems to overall terrestrial productivity. Yet, the temporal (seasonal and developmental) changes in diversity effects on below-ground productivity and their underlying mechanisms remain unclear. We hypothesized that (i) diversity effects on fine root productivity increase with stand development, and (ii) increased diversity effects associated with stand development result from augmented horizontal soil space utilization,...

Data from: Cytology and sexuality of 11 species of Elatostema (Urticaceae) in limestone karsts suggests that apomixis is a recurring phenomenon

Long-Fei Fu, Lan-Ying Su, Azim Mallik, Fang Wen & Yi-Gang Wei
Limestone karsts across southern China to southeastern Asia are renowned biodiversity hotspots. The karst are characterized by exposed calcareous rocks, seasonal droughts and thin soils that are deficient in N and P but with high Ca and Mg content. The stressful habitat may result in high biodiversity through mechanisms such as niche differentiation, hybridization, polyploidy and apomixis. The genus Elatostema (Urticaceae) has particularily high species diversity in this area and can be used a model...

Data from: Tree species diversity promotes litterfall productivity through crown complementarity in subtropical forests

Liting Zheng, Han Y.H. Chen & Enrong Yan
1. The role of niche complementarity for driving the positive biodiversity-ecosystem productivity relationship has been widely recognized, but there is scant evidence regarding the role of tree canopy structure on this relationship. Litterfall productivity is proportional to forest net primary productivity in natural forests, and we hypothesized that litterfall productivity would increase with tree species diversity via increased tree crown complementarity. 2. We investigated annual litterfall productivity, species diversity, tree crown architecture, soil moisture content,...

Understanding behavioural responses to human-induced rapid environmental change: A meta-analysis

Rachel Gunn, Sally Keith, Ian Hartley, Adam Algar, Petri Niemela & Sally Keith
Behavioural responses are often the first reaction of an organism to human induced rapid environmental change (HIREC), yet current empirical evidence provides no consensus about the main environmental features that animals respond to behaviourally or which behaviours are responsive to HIREC. To understand how changes in behaviour can be predicted by different forms of HIREC, we conducted a meta-analysis of the existing empirical literature focusing on behavioural responses to five axes of environmental change (climate...

Rapid recovery of boreal rove beetle (Staphylinidae) assemblages 16 years after variable retention harvest

Seung-Il Lee, David Langor, John Spence, Jaime Pinzon, Gregory Pohl, Dustin Hartley, Timothy Work & Linhao Wu
Post-harvest recovery of biodiversity is one of the important goals in modern forestry. A variable retention (VR) approach has been of particular interest in North America because it promotes rapid faunal recovery while minimizing the negative lasting impacts of logging on the natural fauna. We studied responses of rove beetles (Coleoptera: Staphylinidae) to a broad range of retention harvests (2, 10, 20, 50, and 75 % retention) in comparison to uncut controls as part of...

Data from: Positive species diversity and above-ground biomass relationships are ubiquitous across forest strata despite interference from overstorey trees

Yu Zhang, Han Y. H. Chen & Anthony R. Taylor
There is growing concern over rates of global species diversity loss and its implications on healthy ecosystem functioning. While positive relationships between tree species diversity and forest biomass production have been observed, forests are structurally complex, consisting of understorey vegetation layers that also contribute to ecosystem functioning as they often account for the majority of species richness. However, relationships between understorey vegetation diversity and function are largely unexplored. Further, few studies have simultaneously assessed how...

Data from: Stand structural diversity rather than species diversity enhances aboveground carbon storage in secondary subtropical forests in Eastern China

Arshad Ali, En-Rong Yan, Han Y. H. Chen, Scott X. Chang, Yan-Tao Zhao, Xiao-Dong Yang & Ming-Shan Xu
Stand structural diversity, typically characterized by variances in tree diameter at breast height (DBH) and total height, plays a critical role in influencing aboveground carbon (C) storage. However, few studies have considered the multivariate relationships of aboveground C storage with stand age, stand structural diversity, and species diversity in natural forests. In this study, aboveground C storage, stand age, tree species, DBH and height diversity indices, were determined across 80 subtropical forest plots in Eastern...

Data from: Reclamation strategies for mined forest soils and overstorey drive understorey vegetation

Han Y. H. Chen, Shekhar R. Biswas, Timothy M. Sobey, Brian W. Brassard, Samuel F. Bartels & Han Y.H. Chen
1. Understorey vegetation accounts for the majority of plant diversity in forest ecosystems and contributes to ecosystem functioning. In restoration of degraded forested ecosystems, however, understorey vegetation is often restored passively, contrasting to clear strategies such as informed species choice and site improvement intervention for overstorey vegetation. The choice of overstorey-centered restoration strategy may have important consequences for understorey vegetation. 2. We examined the effects of substrate material, overstorey type and time since reclamation (age)...

Data from: Life at the top: lake ecotype influences the foraging patterns, metabolic costs and life history of an apex fish predator

Liset Cruz Font, Brian J. Shuter, Paul J. Blanchfield, C. Ken Minns & Michael D. Rennie
1.We used acoustic telemetry and acceleration sensors to compare population-specific measures of the metabolic costs of an apex fish predator living in four separate lakes. We chose our study species and populations to provide a strong test of recent theoretical predictions that optimal foraging by an apex fish predator in a typical aquatic environment would be consistent with feeding to satiation rather than continuous feeding. We chose four populations where the primary prey type differed...

Projected effects of climate change on boreal bird community accentuated by anthropogenic disturbances in western boreal forest, Canada

Philippe Cadieux, Yan Boulanger, Dominic Cyr, Anthony Taylor, David Price, Peter Solymos, Diana Stralberg, Han Chen, Aaron Brecka & Junior Tremblay
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,...

Clients’ and Coaches’ Perspectives of a Life Coaching Intervention for Parents with Overweight/Obesity

Shazya Karmali, Danielle S. Battram, Shauna M. Burke, Anita Cramp, Tara Mantler, Don Morrow, Victor Ng, Erin S. Pearson, Robert Petrella, Patricia Tucker & Jennifer D. Irwin

Registration Year

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  • Lakehead University
  • University of Alberta
  • Natural Resources Canada
  • University of Toronto
  • East China Normal University
  • Chinese Academy of Sciences
  • University of Quebec at Montreal
  • McGill University
  • Environment Canada
  • Queen Mary University of London