Temperate Forests Research Papers - Academia.edu (original) (raw)

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- Applied Mathematics, Earth Sciences, Biomathematics, Biometrics

The Humus Index, based on the visual assessment of topsoil horizons and a classification of humus forms, is a numerical score which can be used as a correlate of stand and soil properties. In oak stands from the Montargis forest (Loiret, France) we observed a good linear relationship of the Humus Index with most parameters describing stand development (age, basal area (BA), height and diameter at breast height of dominants) and soil type (depth of clay horizon). The relationship with parameters describing nutrient availability (exchangeable bases, base saturation) was similarly good but nonlinear. In the studied forest the Humus Index was affected first by stand age and second by soil type. When corrected for age and soil type, data (96 pooled estimates) indicated a slight decrease in the Humus Index (shift towards more active humus forms) in stands converted from old coppices-with-standards when compared with even-aged high forest.

- by Jean-François Ponge
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- Temperate Forests, Tree growth, Oak forests, Humus Index

Exotic species can threaten biodiversity by disrupting ecological interactions among native species. Highly-attractive exotic species can exert a 'magnet effect' by attracting native pollinators, which may have either competitive or facilitative effects on co-flowering native plants. However, those effects may be context-dependent. We used a mistletoe-hummingbird pollination system in the Valdivian rainforest (southern Chile) to test whether the exotic tree Eucalyptus globulus (a highly attractive species to pollinators) acts as a magnet species, affecting the co-flowering native mistletoe. We compared humming-bird abundance, visitation rates, and activity patterns between native forest and abandoned E. globulus plantations. We found that hummingbirds were more abundant and visited more flowers at the plantation irrespective of E. globulus flowering. We observed a significant change of pollinator activity at the native habitat during E. globulus flowering, as hummingbirds visited mistletoe flowers more frequently early in the morning at the plantations and in the afternoon at the native forests. Our results showed that E. globulus acts as an exotic magnet species and can alter pollinator abundance and behavior. Our findings demonstrate the importance of considering local-and landscape-scale processes to understand the effects of magnet species on native plants and suggest that magnet species may influence even highly-attractive plants.

- by Francisco E. Fonturbel
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- Community Ecology, Ecology, Chile, Biological invasions

The study was carried out in Kalsa watershed of Western Himalayan Ecoregion to quantify the landscape structure with special reference to different forest ecosystems. Vegetation and land use map generated using satellite remote sensing data was taken as an input for quantification of landscape structure, which was quantified based on different patch attributes (number, area, shape complexity) and landscape indices viz., Euclidean nearest neighbor distance and contagion. Temperate broadleaf forest exhibited high values for mean patch area, largest patch area, contagion and low values for number of patches, shape complexity and Euclidian nearest neighborhood in contrast to the degraded forest.

- by Duane Peltzer
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- Forestry, Carbon, Forest Ecology And Management, Forest Ecology
- by David Coomes
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- Temperate Forests, Landscape, Multidisciplinary, Ecological Modelling
- by Cesar Cuevas
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- Systematics (Taxonomy), Temperate Forests, FROGS, Chromosomes
- by Partha S Ghose and +3
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- Temperate Forests, Sikkim, Red panda, Eastern Himalayas
- by Horacio Samaniego and +2
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- Conservation Biology, Chile, Forest Ecology, Temperate Forests
- by Nathalie Bréda
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- Forestry, Western Europe, Temperate Forests, Ecophysiology

Quercus (oak) is among the most speciose and widespread genera occurring in Mexico; paradoxically, the ecological knowledge about Mexican oak forests is meager. Here we describe the floristic composition, diversity, and structure of the terrestrial component of the oak forests of the El Tepozteco National Park (TNP), Central Mexico, and relate their floristic and structural heterogeneity to the geomorphological complexity of the park. We randomly distributed sixty 100-m2 plots among six geomorphological units: the lava fields of the Chichinautzin, Suchiooc, Otates (upper and lower) and Oclayuca volcanoes, and the El Tepozteco Range. Vegetation structure and diversity were described by geomorphological unit and for the oak forest as a whole for canopy (DBH ≥ 2.5 cm) and understory plants. We report 324 vascular plant species recorded in the plots, plus 17 species collected outside the plots (a total of 341 species, 208 genera and 88 families). The family with more species was Asteraceae (57) and the most speciose genus was Salvia (10). Geomorphological units differed in mean species richness per plot (12.0-33.5 species), absolute richness (60-149 species), and species’ structural contributions; structural differences were also observed, but were not always significant. Quercus rugosa was dominant in Chichinautzin, Suchiooc, and upper Otates; Styrax ramirezii in lower Otates and Oclayuca, and Quercus castanea and Q. obtusata shared dominance in El Tepozteco Range (the unit with the largest overall richness and oak species diversity). The structure and composition of TNP oak forests are highly variable, apparently due to the region’s complex geological past. This heterogeneity should guide the conservation and restoration of these forests.

- by Sebastian Block and +1
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- Temperate Forests, Vegetation, Parques Nacionales, Oak forests
- by Marcia Rocha
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- Forestry, Climate Change, Economic Growth, Carbon
- by Leonor Adán Alfaro
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- Temperate Forests, Watercraft, Magallania
- by Mark Hill
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- Western Europe, Plant Biology, Biogeography, Biodiversity

Food webs based on dead organic matter have received relatively little research attention. Here we focus on dead-wood-dependent (saproxylic) arthropod communities—an overlooked component of forest biodiversity that contributes to decomposition of fallen trees and nutrient cycling. First, we summarized information on factors that impact saproxylic arthropod biodiversity via a descriptive mini-review of the literature, given that the structure of food webs should be contingent upon local community composition, species richness, and/or species abundances within and among neighboring rotting logs. Next, we coupled intensive fieldwork with molecular approaches to taxonomic identification of saproxylic arthropods sampled from rotting logs in the southern Appalachian Mountains, and synthesized information on their feeding ecology, in order to infer trophic interactions. Our descriptive mini-review highlighted major influences of local-scale (site-specific) factors affecting biodiversity, and by extension, food web structure; a pronounced publication bias toward saproxylic beetles from evergreen forests in Europe was also evident. Our empirical data on community composition of rotting logs at intermediate to late stages of decay revealed a complex food web structure. This comprised internal and external primary nutrient sources (dead wood within logs vs. nearby living trees and fallen leaves), a diverse suite of primary consumers (wood-feeding detritivores, leaf litter-feeding detritivores, as well as herbivores and fungivores), several secondary consumer functional groups (omnivorous scavengers and ectoparasites or parasitoids), and top-level carnivorous predators that were mostly made up of spiders, Opiliones, and centipedes. We close by discussing persistent challenges and limitations, and suggest future research directions.

- by S. Burgess and +1
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- Temperate Forests, Food webs, Mitochondrial DNA, Molecular taxonomy
- by NOYAN KUSMAN
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- Mediterranean, Temperate Forests, Potato, Hybrid
- by Erik Jeppesen
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- Earth Sciences, Climate Change, Temperate Forests, Biological Sciences
- by Harald Beck
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- Temperate Forests, Global Warming, White-Tailed Deer, Carbon Storage

Spectral indices derived from optical remote sensing data have been widely used for fire-severity classification in forests from local to global scales. However, comparative analyses of multiple indices across diverse forest types are few. This represents an information gap for fire management agencies in areas like temperate southeastern Australia, which is characterised by a diversity of natural forests that vary in structure, and in the fire-regeneration strategies of the dominant trees. We evaluate 10 spectral indices across eight areas burnt by wildfires in 1998, 2006, 2007, and 2009 in southeastern Australia. These wildfire areas encompass 13 forest types, which represent 86% of the 7.9M ha region's forest area. Forest types were aggregated into six forest groups based on their fire-regeneration strategies (seeders, resprouters) and structure (tree height and canopy cover). Index performance was evaluated for each forest type and forest group by examining its sensitivity to four fire-severity classes (unburnt, low, moderate, high) using three independent methods (anova, separability, and optimality). For the best-performing indices, we calculated index-specific thresholds (by forest types and groups) to separate between the four severity classes, and evaluated the accuracy of fire-severity classification on independent samples. Our results indicated that the best-performing indices of fire severity varied with forest type and group. Overall accuracy for the best-performing indices ranged from 0.50 to 0.78, and kappa values ranged from 0.33 (fair agreement) to 0.77 (substantial agreement), depending on the forest group and index. Fire severity in resprouter open forests and woodlands was most accurately mapped using the delta Normalised Burnt ratio (dNBR). In contrast, dNDVI (delta Normalised difference vegetation index) performed best for open forests with mixed fire responses (resprouters and seeders), and dNDWI (delta Normalised difference water index) was the most accurate for obligate seeder closed forests. Our analysis highlighted the low sensitivity of all indices to fire impacts in Rainforest. We conclude that the optimal spectral index for quantifying fire severity varies with forest type, but that there is scope to group forests by structure and fire-regeneration strategy to simplify fire-severity classification in heterogeneous forest landscapes.

- by Bang Nguyen Tran
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- Remote Sensing, Ecosystems Ecology, Fire Ecology, Optimality Theory
- by lauro López-Mata
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- Diversity, Temperate Forests, Biological Sciences, Beta diversity

South American temperate forests are globally exceptional for their high concentration of endemic species. These forests are among the most endangered ecosystems on Earth because nearly 70% of them have been lost. Current knowledge of most Neotropical forest owls is limited. I studied how environmental and habitat conditions might influence the ecology of sympatric forest owls, and evaluated whether owls can be used as surrogates for temperate forest biodiversity. Specifically, I examined (i) factors associated with the detectability, (ii) occurrence rates and habitat-resource utilization across spatial scales, and (iii) surrogacy reliability of the habitat-specialist rufous-legged owl (Strix rufipes) and the habitat-generalist austral pygmy-owl (Glaucidium nana) in southern Chile. During 2011-2013, I conducted 1,145 owl surveys, 505 vegetation surveys and 505 avian point-transects across 101 sites comprising a range of conditions from degraded habitat to structurally complex old-growth forest stands. I recorded 292 detections of S. rufipes and 334 detections of G. nana. Detectability for both owls increased with greater moonlight and decreased with environmental noise, and greater wind speed decreased detectability for G. nana. Detection of both species was positively correlated with the detection of the other species. For S. rufipes, occurrence probability ranged from 0.05-1 across sites, and was positively associated with bamboo density and the variability in diameter at breast height of trees (multi-aged forests). For G. nana, occurrence ranged from 0.67-0.98, but no habitat characteristic was related to this species occurrence. Relative to G. nana, S. rufipes had lower total resource utilization, but achieved similar peak occurrence for resources related to stand-level forest complexity and forest homogeneity at the landscape scale. I found that only S. rufipes was a reliable surrogate for all avian biodiversity measures, including endemism and functional diversity. With increasing occurrence of habitat-specialist owls, the density of target specialized biodiversity (guilds and communities) increased non-linearly and peaked at the least degraded sites. This “specialist aggregation” was driven by forest-stand structural complexity. Forest management practices that maintain multi-aged stands with large trees and high bamboo cover will benefit both owl species, and likely will benefit vulnerable endemic species and specialized avian communities in temperate forests.

- by Frank Dziock
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- Forestry, Structure, Forest Ecology And Management, Air pollution
- by José Tomás Ibarra and +2
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- Forest Ecology, Temperate Forests, Andes, Mamiferos

The present study is an attempt to analyze and assess the anthropogenic pressure and status of exotic species in the forests of Lolab Valley, Kashmir (India). Because of continuous and heavy grazing, and illegal encroachments, the pastures and forest-areas are deteriorated to critical levels. The pressure is also developing on the most favorite and preferred fuel wood tree species that include Cedrus deodara, Pinus excelsa, and Abies pindrow. The Kashmir Himalaya, known for its indigenous and endemic flora, also provides home to a large number of exotic plants, which exhibit a wide taxonomical and distributional stretch. The inventorization and documentation of its exotics have received a little or negligible attention. The present study has revealed that the exotic flora of Lolab valley is represented by a total of 30 species belonging to 22 families. The family Salicaceae (39%) proved to be the largest family fallowed by Rosaceae (31%), Rununculaceae (15%) and Moraceae (15%). Contribution of different geographical regions in terms of nativity shows that highest number of alien species have come from the continental Europe (42%) followed by Asia (31%) and North America (13%). In contrast, European flora contributed maximum percentage of species (42%) to the alien flora of Lolab valley.

- by D.M. Mahajan
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- Exotic Species, Temperate Forests, Kashmir, Himalayas

- by Marcia Rocha
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- Forestry, Climate Change, Economic Growth, Carbon

Wild cherry trees produce high-quality timber and
provide multiple ecosystemservices. However, planting and tending cherry stands in conventional rows are too costly. Therefore, low density group planting was trialled as an alternative to row planting. The mortality, growth, and quality of planted cherry trees were compared between the group and row planting. The influence of neighbourhood competition and light availability on growth and quality was studied. The group and row planting of cherry trees were established at a wind-thrown site in southwestern Germany in the year 2000. In group planting, five cherry seedlings and seven lime seedlings (Tilia cordata Mill.) were planted with
a 1 9 1 m spacing. In total, 60 groups were planted per
hectare with a 13 9 13 m spacing. In contrast, 3300 seedlings (2475 cherries and 825 limes) were planted per hectare in row planting with a 3 9 1 m spacing. Ten groups and plots (10 9 10 m) were randomly established in group and row planting stand, respectively. The survival rate, stability (height to diameter ratio), diameter, and height growth were significantly higher in group planting. In the group plantings,
40.5% of cherry trees had straight stems and 13.5% had a monopodial crown compared with 15% with straight stems and 2% with a monopodial crown in row planting. The proportion of dominant cherry trees in canopy was 49% in groups compared with 22% in rows. The length of branch free bole was significantly higher in cherries planted in groups than those grown in rows. Intra- and interspecific competition reduced the growth and stability of cherry trees in row planting, but not in group planting. Light availability did not cause any significant effects on growth and quality between group and row planting. This first study on cherry group planting indicates that the survival rate, growth, and
tree quality were higher in groups than in rows at this early development stage. The competition by naturally born seedlings was an important reason for the difference in performance between group and row planting. This study will encourage forest practitioners to establish more cherry group planting trials on multiple sites to test the effectiveness of this alternative technique as a tool of regeneration and restoration silviculture.

- by Dr. Somidh Saha
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- Forestry, Silviculture, Forest Ecology And Management, Ecology
- by Simon R Leather and +1
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- Coevolution, Adaptation, Temperate Forests, Color Perception
- by Juan C. Torres-Mura
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- Ornithology, Temperate Forests

Owing to the growing sensitivity of forests to drought under the warming climate, more attention should be paid to the role of soil drought, plant–plant interactions, tree species and structural diversity, and other abiotic factors on the crown die-back of trees. We studied how permanent soil water stress had impacted on crown die-back of beech trees (Fagus sylvatica L.) at their drought limit in near-natural temperate forests of Germany and Switzerland. Crown die-back was quantified by the proportion of dead above-ground biomass to total biomass for the individual beech tree. We quantified the available soil water storage capacity as a measure of soil drought stress in combination with other biotic (e.g., plant–plant interactions, tree species diversity, stand structural diversity, plant height and proportion of oak trees) and abiotic (e.g., light availability, soil pH, soil bulk density, potential evapotranspiration) factors to determine the influence of those stressors on crown die-back. We found increases in soil water storage capacity, neighbourhood interactions, plant height and light decreased crown die-back of the beech trees. These stressors differently influenced the die-back among different parts of tree crown. Soil water storage capacity, light availability, intra- and interspecific interactions, plant height and tree species diversity had the strongest influence on die-back in the upper part of the crown. Permanent death of beech trees occurred when the amount of dead above-ground biomass exceeded a 58% mortality threshold. We conclude that vitality of beech trees in drought stressed forests is related to soil water storage capacity, light availability, neighbourhood interactions and tree species diversity.

- by Dr. Somidh Saha and +1
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- Forestry, Plant Ecology, Climate Change, Climate Change Adaptation

Machine learning and spectral index (SI) thresholding approaches have been tested for fire-severity mapping from local to regional scales in a range of forest types worldwide. While index thresholding can be easily implemented, its operational utility over large areas is limited as the optimum index may vary with forest type and fire regimes. In contrast, machine learning algorithms allow for multivariate fire classifications. This study compared the accuracy of fire-severity classifications from SI thresholding with those from Random Forests (RF). Reference data were from 3730 plots within the boundaries of eight major wildfires across the six temperate forest 'functional' groups of Victoria, southeastern Australia. The reference plots were randomly divided into training and validation datasets (60/40) for each fire-severity class (unburnt, low, moderate, high) and forest functional group. SI fire-severity classifications were conducted using thresholds derived in a previous study based on the same datasets. A RF classification algorithm was trained to derive fire-severity levels based on appropriate spectral indices and their temporal difference. The RF classification outperformed the SI thresholding approach in most cases, increasing overall accuracy by 11% on a forest-group basis, and 16% on an individual wildfire basis. Adding more predictor variables into the RF algorithm did not improve classification accuracy. Greater overall accuracies (by 12% on average) were achieved when in situ data (rather than data from other fires) were used to train the RF algorithm. Our study shows the utility of Random Forest algorithms for streamlining fire-severity mapping across heterogeneous forested landscapes.

- by Bang Tran
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- Fire Ecology, Temperate Forests, Wildfires, Eucalypts

Background: While the effects of prescribed burning on tree regeneration and on pyrophilous and/or saproxylic species are relatively well known, effects on other organisms are less clear. The primary aim of this systematic review was to clarify how biodiversity is affected by prescribed burning in temperate and boreal forests, and whether burning may be useful as a means of conserving or restoring biodiversity, beyond that of pyrophilous and saproxylic species. Methods: The review examined primary field studies of the effects of prescribed burning on biodiversity in boreal and temperate forests in protected areas or under commercial management. Non-intervention or alternate levels of intervention were comparators. Relevant outcomes were species richness and diversity, excluding that of pyrophilous and saproxylic species. Relevant studies were extracted from a recent systematic map of the evidence on biodiversity impacts of active management in forests set aside for conservation or restoration. Additional searches and a search update were undertaken using a strategy targeted to identify studies focused on prescribed burning interventions. Grey literature and bibliographies of relevant published reviews were also searched for evidence. Studies were assessed for internal and external validity and data were extracted, using validity assessment and data extraction tools specifically designed for this review. Studies were presented in a narrative synthesis and interactive map, and those which were suitable were quantitatively synthesised using meta-analyses, subgroup analysis and meta-regression. Results: Searches generated a total of 12,971 unique records. After screening for relevance, 244 studies (from 235 articles) were included in this review. Most studied forests were located in the USA (172/244), with the rest located in Canada, Europe and Australia. Eighty-two studies reporting 219 comparisons were included in the quantitative synthesis. Within the meta-analyses for each group of taxa, we identified a small to moderate volume of evidence, and heterogeneity was ubiquitous. Prescribed burning had significant positive effects on vascular plant richness, non-native vascular plant richness, and in broadleaf forests, herbaceous plant richness. Time since the burn, forest type and climate zone were significant moderators predicting the effect of burning on herbaceous plant richness. No other significant relationships were identified.

- by Jacqualyn Eales and +2
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- Environmental Management, Prescribed Fire, Temperate Forests, Biodiversity Research
- by Luis Cayuela
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- Conservation, Modeling, Biodiversity, Temperate Forests
- by James B Riding
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- Earth Sciences, Geology, Temperate Forests, Quaternary

Greenhouse gas emissions have significantly altered global climate, and will continue to do so in the future. Increases in the frequency, duration, and/or severity of drought and heat stress associated with climate change could fundamentally alter the composition, structure, and biogeography of forests in many regions. Of particular concern are potential increases in tree mortality associated with climate-induced physiological stress and interactions with other climate-mediated processes such as insect outbreaks and wildfire. Despite this risk, existing projections of tree mortality are based on models that lack functionally realistic mortality mechanisms, and there has been no attempt to track observations of climate-driven tree mortality globally. Here we present the first global assessment of recent tree mortality attributed to drought and heat stress. Although episodic mortality occurs in the absence of climate change, studies compiled here suggest that at least some of the world's forested ecosystems already may be responding to climate change and raise concern that forests may become increasingly vulnerable to higher background tree mortality rates and die-off in response to future warming and drought, even in environments that are not normally considered water-limited. This further suggests risks to ecosystem services, including the loss of sequestered forest carbon and associated atmospheric feedbacks. Our review also identifies key information gaps and scientific uncertainties that currently hinder our ability to predict tree mortality in response to climate change and emphasizes the need for a globally coordinated observation system. Overall, our review reveals the potential for amplified tree mortality due to drought and heat in forests worldwide.

- by Haroun Chenchouni and +3
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- Climate Change, Climate Change Adaptation, Adaptation to Climate Change, Disaster risk management

In Mexico, the timber species extinction risk is only considered as habitat loss and environmental changes, but there are different present and past hazards that interact to transform the current and potential distribution of such species. The objective of this paper is to elaborate species distribution models of timber species of pine in response to hazardous factors and their vulnerability in the path of sustainable management at a national scale. The localization points of 28 endemic species of Pinus were used to make the species distribution models with different climatic, topographic and soil variables in the software MaxEnt to get the potential distribution of the niche. The hazardous factors taken into account for this paper were fire events, land-use change, plagues, the incidence of 3 different climate change models; and the signs of vulnerability were classified as the state of conservation and protection of the species and the lack of forestry management in the production of timber. Based in the 28 distribution maps of the pine timber species there can be established zones for different types of interests, from conservation zone for high-risk species (Pinus mazimartinezii) to zone where it can be factual the increase or the start of sustainable timber production or forestry of new species or in new sites, like the potential of Pinus lumholtzii for timber and chemical production, that is only locally used.
The models can be used as well for the proposal of new areas for conservation of the pine diversity, as the extremely narrow distribution of Pinus jaliscana West of México, but with the possibility of migration with the climate change fluctuations South of the country. Furthermore, it can be possible to define zones with reforestation possibilities according to species characteristics that make them resistant to extreme environmental characteristics that can slow down, diminish or stop environmental, social and economic problems. All the results are fundamental for the elaboration of projects directed for sustainable management and the construction of public politics that ensure the conservation and utilization of pine timber species.

- by Monica Barcenas
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- Temperate Forests, Ecological Modelling, Mexico, Pinus spp

Trabajo presentado en las Jornadas Arqueológicas Cuyanas, Malargüe, 9-11 mayo 2018

- by Constanza Roa Solís and +1
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- Temperate Forests, Archeobotany, Maize, Crop Production

Habitat loss and degradation have the potential to alter the species richness–functional diversity relationship
decreasing both species richness and functional richness, and increasing functional biotic homogenization.
These anthropogenic disturbances may have strong impacts on species-poor systemswith lowfunctional redundancy.
We tested the species richness–functional diversity relationship and the potential effects of deforestation
and degradation on functional diversity of avian assemblages in a Biodiversity Hotspot, in southern Chile. For 101
sites established across a disturbance gradient, we conducted 505 point-transect surveys to measure avian
community structure, 505 vegetation plots to quantify stand-level structure, and measured deforestation at
the landscape-level. We used three functional diversity indices for avian assemblages (functional richness,
functional evenness, and community-weighted specialization as a measure of functional biotic homogenization).
We found a non-saturating relationship between species richness and both functional richness and communityweighted
specialization, suggesting low functional redundancy. We also found a non-significant decline of functional
evenness indicating that when adding new species to the initial pool, functional redundancy increases
slightly. Deforestation led to a decrease in both functional richness and community-weighted specialization,
particularly precluding the persistence of specialized species in disturbed forests. Functional evenness did not
vary with deforestation suggesting that the regularity of density distribution in filled niche volume may be relatively
resilient to disturbance. However, the fact that community-weighted specialization decreased linearly
under deforestation serves as evidence of functional biotic homogenization processes (“loser” specialists being
replaced by “winner” generalist species) in a Biodiversity Hotspot.

- by Francisco Ramirez Pacheco
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- Climate Change, Conservation, Ecology, Biodiversity

Climate change and habitat fragmentation are considered key pressures on biodiversity, and mammalian carnivores with a limited geographical distribution are particularly vulnerable. The kodkodLeopardus guigna, a small felid endemic to the temperate forests of southern Chile and Argentina, has the smallest geographical range of any New World felid. Although the species occurs in protected areas in both countries, it is not known how well these areas protect the kodkod either currently or under climate change scenarios. We used species distribution models and spatial analyses to assess the distribution of the kodkod, examining the effects of changes in human land use and future climate change. We also assessed the species’ present representation in protected areas and in light of climate change scenarios. We found that the kodkod has already lost 5.5% of its range as a result of human land use, particularly in central areas of its distribution with intermediate habitat suitability. Cl...

- by Griet Cuyckens
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- Zoology, Geography, Ecology, Temperate Forests

Hibernation (i.e., multiday torpor) is considered an adaptive strategy of mammals to face seasonal environmental challenges such as food, cold, and/or water shortage. It has been considered functionally different from daily torpor, a physiological strategy to cope with unpredictable environments. However, recent studies have shown large variability in patterns of hibernation and daily torpor (“heterothermic responses”), especially in species from tropical and subtropical regions. The arboreal marsupial “monito del monte” (Dromiciops gliroides) is the last living representative of the order Microbiotheria and is known to express both short torpor episodes and also multiday torpor depending on environmental conditions. However, only limited laboratory experiments have documented these patterns in D. gliroides. Here, we combined laboratory and field experiments to characterize the heterothermic responses in this marsupial at extreme temperatures. We used intraperitoneal data loggers and simultaneous measurement of ambient and body temperatures (TA and TB, respectively) for analyzing variations in the thermal differential, in active and torpid animals. We also explored how this differential was affected by environmental variables (TA, natural photoperiod changes, food availability, and body mass changes), using mixed-effects generalized linear models. Our results suggest that: (1) individuals express short bouts of torpor, independently of TA and even during the reproductive period; (2) seasonal torpor also occurs in D. gliroides, with a maximum bout duration of 5 days and a mean defended TB of 3.6 ± 0.9°C (one individual controlled TB at 0.09°C, at sub-freezing TA); (3) the best model explaining torpor occurrence (Akaike information criteria weight = 0.59) discarded all predictor variables except for photoperiod and a photoperiod by food interaction. Altogether, these results confirm that this marsupial expresses a dynamic form of torpor that progresses from short torpor to hibernation as daylength shortens. These data add to a growing body of evidence characterizing tropical and subtropical heterothermy as a form of opportunistic torpor, expressed as daily or seasonal torpor depending on environmental conditions.

- by Francisco E. Fonturbel
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- Physiology, Zoology, Temperate Forests, Marsupials

Avian reproductive strategies have been hypothesized to vary with elevation. Shorter breeding seasons due to harsh
environmental conditions, and potentially higher predation risks, may reduce clutch sizes at higher elevations, which in
some species leads to increased parental care and offspring survival. However, this phenotypically plastic and
potentially adaptive response has been documented only in a handful of species in the Northern Hemisphere. For the
first time in a southern temperate ecosystem, we studied whether the breeding strategy of a secondary cavity-nester
varied along an elevational gradient in Andean temperate forests, Chile. We installed 240 nest-boxes at 260–1,115 m
elevation and monitored the breeding activity of 162 nests of Thorn-tailed Rayaditos (Aphrastura spinicauda) over 2
seasons (2010–2012). We included 50 nests from a third season only for recording clutch size and nestlings per clutch.
As predicted, the breeding season was shorter in highland forests than in lower elevations, by 28% and 55% over the 2
successive seasons. Although timing of egg laying (1 egg every second day) and incubation period (average¼15 days)
did not vary with elevation, we found smaller clutch sizes (average ¼ 4.1 vs. 4.5) and fewer nestlings per clutch
(average ¼ 3.5 vs. 4.2) at higher elevations. The extent of parental care, expressed as the duration of the nestling
period, was slightly but significantly greater in highland than in lowland forests (22.2 vs. 21.6 days). Despite the longer
nestling period at higher elevations, nesting success was lower at high elevations, mainly because of nest predation.
Our findings suggest that Thorn-tailed Rayaditos may change to a slower reproductive strategy along elevational
gradients. Yet these changes do not appear to compensate for the increased predation rates at higher elevations,
calling into question the potential adaptive significance of this strategy.

- by José Tomás Ibarra and +2
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- Ornithology, Conservation Biology, Temperate Forests, Andes

We measured the effect of elevated atmospheric CO2 on atmospheric nitrogen (N2) fixation for the tree species Alnus glutinosa growing in monoculture or in mixture with the non-N2-fixing tree species Betula pendula and Fagus sylvatica. We addressed the hypotheses that 1: N2 fixation in A. glutinosa will increase in response to increased atmospheric CO2 concentrations, when growing in monoculture, 2: the impact of elevated CO2 on N2 fixation in A. glutinosa is the same in mixture and in monoculture and 3: the impacts of elevated CO2 on N cycling will be evident in a decrease in leaf δ15N and in the soil-leaf enrichment factor (EF), and that these impacts will not differ between mixed and single species stands. Trees were grown in a forest plantation on former agricultural fields for 4 growing seasons, after which the trees were on average 3.8 m tall and canopy closure had occurred. Atmospheric CO2 concentrations were maintained at either ambient or elevated (by 200 ppm) concentrations using a free-air CO2 enrichment (FACE) system. Leaf δ15N was measured and used to estimate the amount (Ndfa) and proportion (%Ndfa) of N derived from atmospheric fixation. On average 62% of the N in A. glutinosa leaves was from fixation. %Ndfa and Ndfa for A. glutinosa trees in monoculture did not increase under elevated CO2, despite higher growth rates. However, N2 fixation did increase for trees growing in mixture, despite the absence of significant growth stimulation. There was evidence that fixed N2 was transferred from A. glutinosa to F. sylvatica and B. pendula, but no evidence that this affected their CO2 response. This study shows that N2 fixation in A. glutinosa may be higher in a future elevated CO2 world, but that this effect will only occur where the trees are growing in mixed species stands.

- by Jonathan Millett
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- Environmental Science, Forestry, Ecosystems Ecology, Plant Ecology

A field experiment was conducted at Shalimar Campus during Kharif seasons of 2004 and 2005 on a silty clay loam soil, medium in available N and K, low in available P to study the production performance of soybean as influenced by seed rate, row spacing and fertility levels under temperate conditions. The experiment comprising 27 treatment combinations viz., 3 levels each of seed rate (40, 60 and 80 kg ha-1), row spacing (30, 45 and 60 cm) and fertility (40:60:40, 60:90:60 and 80:120:80 of N: P2O5: K2O kg ha-1) was laid out in split plot design replicated thrice. Lower seed rate i.e. 40 kg ha-1 produced significantly higher number of branches plant-1, test weight, number of pods plant-1 and seeds pod-1. Contrary to this, seed and straw yield were found significantly superior under seed rate of 80 kg ha-1 over 40 kg ha-1. The extent of increase was 21.75 % for grain yield and 20.68 % for straw yield. Whereas row spacing of 45 cm proved significantly superior over 30 cm and remained at...

- by Badrul Hasan
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- Mathematics, Fertility, Temperate Forests, Yield

We used long-term data collected from 22 study sites in northern hardwood stands comprised of sugar maple (Acer saccharum Marsh.), yellow birch (Betula alleghaniensis Britt.), and American beech (Fagus grandifolia Ehrh.) to establish relationships between sapling abundance and tree ingrowth. After 10 years, postharvest sapling density in the 6 cm diameter class (5.1–7.0 cm) showed linear relationships with ingrowth. Proportion of variation explained (r2) varied from 36% to 83% depending upon tree species and silvicultural treatment (partial cutting vs. uncut control). After 20 years, linear relationships were also established (r2 = 24–65%) between ingrowth and sapling density in the 2 cm diameter class (1.1–3.0 cm). From a wide pool of variables related to stand species composition, climate, physiography, and soil nutrients, postharvest sapling density was most strongly correlated to merchantable tree density (r = 0.43–0.75). Sugar maple sapling density was also positively correlated with base saturation and calcium saturation of the B horizon (r = 0.56 and 0.58). Over a 30-year period, the increase in American beech sapling basal area was substantial compared to mitigated increases found in sugar maple and yellow birch depending upon treatment. Our results provide useful information on integration of sapling data into forest management.

- by Scott Mitchell
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- Bioinformatics, Temperate Forests, Life Cycle, Zombie
- by Olivier Chabrerie
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- Diversity, Invasive Species, Community, Biodiversity