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Ernst Detlef Schulze

Other affiliations: University of Idaho, University of Utah, University of Würzburg  ...read more
Bio: Ernst Detlef Schulze is an academic researcher from Max Planck Society. The author has contributed to research in topics: Biodiversity & Ecosystem. The author has an hindex of 133, co-authored 670 publications receiving 69504 citations. Previous affiliations of Ernst Detlef Schulze include University of Idaho & University of Utah.


Papers
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Journal ArticleDOI
TL;DR: The Wetzstein site is part of the CarboEurope-IP flux-network and the CO2-exchange of this spruce forest is of general ecological interest as the site is typical for central European spruce forests at mountainous elevation as mentioned in this paper.

62 citations

Journal ArticleDOI
TL;DR: Non-irrigated cowpeas avoided drought by maintaining low transpiration rates due to reduced leaf area and reduced transpiration per unit leaf area compared with irrigated plants.
Abstract: The factors responsible for the extreme drought avoidance of cowpeas [Vigna unguiculata (L.) Walp.] previously observed in several field environments were investigated. Drought avoidance is defined as the extent to which high plant water potentials are maintained in the presence of environmental drought. Cowpeas were grown in controlled environments and subjected to either frequent irrigation or progressive drought. Plants in the drought treatment were grown for up to 2 months on 2-2.5 litres per plant of available water supplied 5 days after emergence. Transpiration of whole plants was determined by pot weighing, and leaf water status was determined with a pressure chamber. Well watered cowpeas avoided drought by two mechanisms: by avoiding water loss, because at constant air temperature transpiration increased only slightly with increases in vapour pressure deficit from 20 to 40 mbar; and due to an efficient water transport system which resulted in only small decreases in pressure chamber values with increases in transpiration at high rates of transpiration. Non-irrigated cowpeas avoided drought by maintaining low transpiration rates due to reduced leaf area and reduced transpiration per unit leaf area compared with irrigated plants.

62 citations

Journal ArticleDOI
TL;DR: The regulation of leaf gas exchange in Larix under the extreme climatic conditions of eastern Siberia is discussed and structural and physiological variations within the tree crowns and between trees that reduced maximum assimilation and leaf conductance by about 40 and 60%, respectively.
Abstract: In July 1993, we measured leaf conductance, carbon dioxide (CO(2)) assimilation, and transpiration in a Larix gmelinii (Rupr.) Rupr. ex Kuzen forest in eastern Siberia. At the CO(2) concentration of ambient air, maximum values (mean of 10 highest measured values) for CO(2) assimilation, transpiration and leaf conductance for water vapor were 10.1 micro mol m(-2) s(-1), 3.9 mmol m(-2) s(-1) and 365 mmol m(-2) s(-1), respectively. The corresponding mean values, which were much lower than the maximum values, were 2.7 micro mol m(-2) s(-1), 1.0 mmol m(-2) s(-1) and 56 mmol m(-2) s(-1). The mean values were similar to those of Vaccinium species in the herb layer. The large differences between maximum and actual performance were the result of structural and physiological variations within the tree crowns and between trees that reduced maximum assimilation and leaf conductance by about 40 and 60%, respectively. Thus, maximum assimilation and conductance values averaged over the canopy were 6.1 micro mol m(-2) s(-1) and 146 mmol m(-2) s(-1), respectively. Dry air caused stomatal closure, which reduced assimilation by an additional 26%. Low irradiances in the morning and evening had a minor effect (-6%). Daily canopy transpiration was estimated to be 1.45 mm day(-1), which is higher than the value of 0.94 mm day(-1) measured by eddy covariance, but similar to the value of 1.45 mm day(-1) calculated from the energy balance and soil evaporation, and less than the value of 2.1 mm day(-1) measured by xylem flux. Daytime canopy carbon assimilation, expressed on a ground area basis, was 0.217 mol m(-2) day(-1), which is higher than the value measured by eddy flux (0.162 mol m(-2) day(-1) including soil respiration). We discuss the regulation of leaf gas exchange in Larix under the extreme climatic conditions of eastern Siberia (temperature > 35 degrees C and vapor pressure deficit > 5.0 kPa).

62 citations

Book ChapterDOI
01 Jan 2000
TL;DR: Detailed knowledge of the biology of C cycling and that of other major and minor elements is urgently needed because the Kyoto Protocol demands strategies to balance industrial emissions by biological C fixation.
Abstract: Our understanding of the biology of major biogeochemical cycles came initially from, and is still based upon, field observations (Bolin et al. 1979; Clark and Rosswall 1981; Apps and Price 1996). This is in contrast to very advanced models, which explore the physics of the climate system and are based on laws of physics or chemistry with a mechanistic understanding of the underlying processes (Houghton et al. 1996; Bengtsson 1999). For the biologist, the responses of organisms reach far beyond physicochemical reactions, and they include genetically regulated changes in physiological pathways or activation of enzyme systems as part of acclimations and adaptations that are coupled with climate and species composition changes. Generic predictions thus remain elusive because there are too many species and pathways. Although climate greatly influences the biogeochemical cycles, models that include biology thus remain at a correlative level. Moreover, the cycling of elements like carbon (C) cannot readily be separated from the abundance, state and cycles of other elements, especially nitrogen (N) (Schulze et al. 1994) which, in turn, is tied to the cycling of other elements (Ulrich 1987). Nevertheless, detailed knowledge of the biology of C cycling and that of other major and minor elements is urgently needed because the Kyoto Protocol demands strategies to balance industrial emissions by biological C fixation (WBGU 1998; IGBP 1998). By this protocol, mankind is taking a first step to deliberately engineer the biology of the global C cycle; but without full understanding of the underlying processes, there is a risk of serious deleterious side effects (Schellnhuber and Wenzel 1998; Schellnhuber 1999).

61 citations

Journal ArticleDOI
TL;DR: An empirical model of CO2 uptake and water loss of leaves is established using steady-state responses of gas exchange to climatic factors as input and the response surface of net CO2 assimilation and leaf conductance to climate can be derived.
Abstract: An empirical model of CO2 uptake and water loss of leaves is established using steady-state responses of gas exchange to climatic factors as input. From the model the response surface of net CO2 assimilation and leaf conductance to climate can be derived. The model consists of two submodels, one describing the response of CO2 uptake to light and temperature, the other describing the response of leaf conductance to temperature and humidity. Both submodels are joined via the linear relationship between CO2 uptake and leaf conductance at short-term (minutes) variation of irradiance. From the humidity response of leaf conductance and the 'demand function' (Raschke 1979) of CO2 uptake in the mesophyll, the effect of stomata on the diffusion of CO2 between leaf and air is determined. The model is tested by comparing measured and calculated diurnal courses of gas exchange for two plants of Pinus silvestris, differing in photosynthetic capacity due to different levels of magnesium nutrition. Applications and limitations of the model are discussed.

61 citations


Cited by
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Journal ArticleDOI
TL;DR: Preface to the Princeton Landmarks in Biology Edition vii Preface xi Symbols used xiii 1.
Abstract: Preface to the Princeton Landmarks in Biology Edition vii Preface xi Symbols Used xiii 1. The Importance of Islands 3 2. Area and Number of Speicies 8 3. Further Explanations of the Area-Diversity Pattern 19 4. The Strategy of Colonization 68 5. Invasibility and the Variable Niche 94 6. Stepping Stones and Biotic Exchange 123 7. Evolutionary Changes Following Colonization 145 8. Prospect 181 Glossary 185 References 193 Index 201

14,171 citations

Journal ArticleDOI
TL;DR: Understanding this complexity, while taking strong steps to minimize current losses of species, is necessary for responsible management of Earth's ecosystems and the diverse biota they contain.
Abstract: Humans are altering the composition of biological communities through a variety of activities that increase rates of species invasions and species extinctions, at all scales, from local to global. These changes in components of the Earth's biodiversity cause concern for ethical and aesthetic reasons, but they also have a strong potential to alter ecosystem properties and the goods and services they provide to humanity. Ecological experiments, observations, and theoretical developments show that ecosystem properties depend greatly on biodiversity in terms of the functional characteristics of organisms present in the ecosystem and the distribution and abundance of those organisms over space and time. Species effects act in concert with the effects of climate, resource availability, and disturbance regimes in influencing ecosystem properties. Human activities can modify all of the above factors; here we focus on modification of these biotic controls. The scientific community has come to a broad consensus on many aspects of the re- lationship between biodiversity and ecosystem functioning, including many points relevant to management of ecosystems. Further progress will require integration of knowledge about biotic and abiotic controls on ecosystem properties, how ecological communities are struc- tured, and the forces driving species extinctions and invasions. To strengthen links to policy and management, we also need to integrate our ecological knowledge with understanding of the social and economic constraints of potential management practices. Understanding this complexity, while taking strong steps to minimize current losses of species, is necessary for responsible management of Earth's ecosystems and the diverse biota they contain.

6,891 citations

Journal ArticleDOI
08 Aug 2002-Nature
TL;DR: A doubling in global food demand projected for the next 50 years poses huge challenges for the sustainability both of food production and of terrestrial and aquatic ecosystems and the services they provide to society.
Abstract: A doubling in global food demand projected for the next 50 years poses huge challenges for the sustainability both of food production and of terrestrial and aquatic ecosystems and the services they provide to society. Agriculturalists are the principal managers of global useable lands and will shape, perhaps irreversibly, the surface of the Earth in the coming decades. New incentives and policies for ensuring the sustainability of agriculture and ecosystem services will be crucial if we are to meet the demands of improving yields without compromising environmental integrity or public health.

6,569 citations

Journal ArticleDOI
22 Apr 2004-Nature
TL;DR: Reliable quantification of the leaf economics spectrum and its interaction with climate will prove valuable for modelling nutrient fluxes and vegetation boundaries under changing land-use and climate.
Abstract: Bringing together leaf trait data spanning 2,548 species and 175 sites we describe, for the first time at global scale, a universal spectrum of leaf economics consisting of key chemical, structural and physiological properties. The spectrum runs from quick to slow return on investments of nutrients and dry mass in leaves, and operates largely independently of growth form, plant functional type or biome. Categories along the spectrum would, in general, describe leaf economic variation at the global scale better than plant functional types, because functional types overlap substantially in their leaf traits. Overall, modulation of leaf traits and trait relationships by climate is surprisingly modest, although some striking and significant patterns can be seen. Reliable quantification of the leaf economics spectrum and its interaction with climate will prove valuable for modelling nutrient fluxes and vegetation boundaries under changing land-use and climate.

6,360 citations

Journal ArticleDOI
01 Jan 1989
TL;DR: In this article, the physical and enzymatic bases of carbone isotope discrimination during photosynthesis were discussed, noting how knowledge of discrimination can be used to provide additional insight into photosynthetic metabolism and the environmental influences on that process.
Abstract: We discuss the physical and enzymatic bases of carbone isotope discrimination during photosynthesis, noting how knowledge of discrimination can be used to provide additional insight into photosynthetic metabolism and the environmental influences on that process

6,246 citations