Carol A. Brewer

Environmental v. genetically driven variation in ecophysiological traits of Nothofagus pumilio from contrasting elevations

Nothofagus pumilio (Poepp. et Endl.) Krasser is a broadleaved deciduous tree that dominates high-elevation forests in the southern Andes. We evaluated the degree to which differences in stomatal density and physiological traits (net assimilation, conductance and water use efficiency) were related to environmental and genetic influences with elevation by comparing plants growing under field and common garden conditions. Low-elevation leaves under field conditions had fewer stomata, although this pattern was not maintained in the common garden. Assimilation rates were >40% higher for high-elevation plants in the field, and 18% higher in the common garden, than those for low-elevation plants. In addition, under field conditions high-elevation plants tended to have higher stomatal conductance and lower instantaneous water use efficiency than did low-elevation plants; however, these differences were not significant in the common garden. Thus, assimilation seems to be under genetic control whereas ecophysiological traits related to the use of water appear to be more responsive to environmental cues. Our results suggest that plants growing along elevational gradients may show complex ecophysiological patterns. These patterns may be acquired by genetically driven responses to conditions that are fixed throughout the life span of individuals, such as soil nutrients. Also plastic adjustments may favour opportunistic use of available water during the dry season, particularly under Mediterranean-type climate regimes with summer drought.

The Adaptive Importance of Shoot and Crown Architecture in Conifer Trees

In summary, we believe that the primary adaptive significance of the characteristic leaf, shoot, and crown structure of conifer trees is not because a more vertical leaf orientation of a needle-like leaf results in greater light penetration through upper branches to those lower in the leaf crown or less low-temperature limitation to photosynthesis at lower incident light (Sprugel 1989). Instead, the tight packing of needle-like leaves on individual shoots, along with the conical crown shape and layered arrangement of branches, may be essential for survival during winter, the most stressful period of the year. However, evidence suggests that these same structural features may also enhance summer carbon gain by increasing direct sunlight interception, leaf warming, and photosynthesis per unit of stem biomass.

Environmental literacy, ecological literacy, ecoliteracy: What do we mean and how did we get here?

Numerous scholars have argued that the terms environmental literacy, ecological literacy, and ecoliteracy have been used in so many different ways and/or are so all-encompassing that they have very little useful meaning. However, despite the seemingly arbitrary and, at times, indiscriminate use of these terms, tremendous efforts have in fact been made to explicitly define and delineate the essential components of environmental literacy, ecological literacy, and ecoliteracy, and to firmly anchor their characterizations in deep theoretical and philosophical foundations. A driving purpose behind these ongoing conversations has been to advance complete, pedagogy-guiding, and broadly applicable frameworks for these ideals, allowing for standards and assessments of educational achievement to be set. In this manuscript, we review a diversity of perspectives related to the often nuanced differences and similarities of these terms. A classification of the numerous proposed frameworks for environmental literacy, ec...

PATTERNS OF LEAF WETTABILITY ALONG AN EXTREME MOISTURE GRADIENT IN WESTERN PATAGONIA, ARGENTINA

The objective of this study was to investigate patterns of surface features of leaves related to susceptibility to wetness for plants along a strong precipitation gradient. Leaf wettability and droplet retention were examined for leaves of 37 species (representing 28 families) occurring in steppe, ecotone, and temperate rain forest habitats along a steep moisture gradient in northwestern Patagonia, Argentina. Morphological and structural characteristics of leaves significantly affected leaf surface wetness, and these characteristics varied between habitats. Typically, leaves had more stomata on abaxial than adaxial leaf surfaces ( \documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont} \usepackage{stmaryrd} \usepackage{textcomp} \usepackage{portland,xspace} \usepackage{amsmath,amsxtra} \usepackage[OT2,OT1]{fontenc} \newcommand\cyr{ \renewcommand\rmdefault{wncyr} \renewcommand\sfdefault{wncyss} \renewcommand\encodingdefault{OT2} \normalfont \selectfont} \DeclareTextFontCommand{\textcyr}{\cyr} \pagestyle{empty} \DeclareMathSizes{10}{9}{7}{6} \begin{document} \landscape

A Global Lake Ecological Observatory Network (GLEON) for synthesising high–frequency sensor data for validation of deterministic ecological models

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TRAINING ECOLOGISTS TO THINK WITH UNCERTAINTY IN MIND

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Innovation in large lectures—teaching for active learning

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