The Experts below are selected from a list of 1938 Experts worldwide ranked by ideXlab platform
Kazuhiko Takeuchi - One of the best experts on this subject based on the ideXlab platform.
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management applicability of the Intermediate Disturbance Hypothesis across mongolian rangeland ecosystems
Ecological Applications, 2009Co-Authors: Takehiro Sasaki, Satoru Okubo, Tomoo Okayasu, Undarmaa Jamsran, Toshiya Ohkuro, Kazuhiko TakeuchiAbstract:The current growing body of evidence for diversity–Disturbance relationships suggests that the peaked pattern predicted by the Intermediate Disturbance Hypothesis (IDH) may not be the rule. Even if ecologists could quantify the diversity–Disturbance relationship consistent with the IDH, the applicability of the IDH to land management has rarely been addressed. We examined two hypotheses related to the generality and management applicability of the IDH to Mongolian rangeland ecosystems: that the diversity–Disturbance relationship varies as a function of landscape condition and that some Intermediate scales of grazing can play an important role in terms of sustainable rangeland management through a grazing gradient approach. We quantified the landscape condition of each ecological site using an ordination technique and determined two types of landscape conditions: relatively benign and harsh environmental conditions. At the ecological sites characterized by relatively benign environmental conditions, divers...
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management applicability of the Intermediate Disturbance Hypothesis across mongolian rangeland ecosystems
Ecological Applications, 2009Co-Authors: Takehiro Sasaki, Satoru Okubo, Tomoo Okayasu, Undarmaa Jamsran, Toshiya Ohkuro, Kazuhiko TakeuchiAbstract:The current growing body of evidence for diversity-Disturbance relationships suggests that the peaked pattern predicted by the Intermediate Disturbance Hypothesis (IDH) may not be the rule. Even if ecologists could quantify the diversity-Disturbance relationship consistent with the IDH, the applicability of the IDH to land management has rarely been addressed. We examined two hypotheses related to the generality and management applicability of the IDH to Mongolian rangeland ecosystems: that the diversity-Disturbance relationship varies as a function of landscape condition and that some Intermediate scales of grazing can play an important role in terms of sustainable rangeland management through a grazing gradient approach. We quantified the landscape condition of each ecological site using an ordination technique and determined two types of landscape conditions: relatively benign and harsh environmental conditions. At the ecological sites characterized by relatively benign environmental conditions, diversity-Disturbance relationships were generally consistent with the IDH, and maximum diversity was observed at some Intermediate distance from the source of the grazing gradient. In contrast, the IDH was not supported at most (but not all) sites characterized by relatively harsh environmental conditions. The Intermediate levels of grazing were generally located below the ecological threshold representing the points or zones at which Disturbance should be limited to prevent drastic changes in ecological conditions, suggesting that there is little "conundrum" with regard to Intermediate Disturbance in the studied systems in terms of land management. We suggest that the landscape condition is one of the primary factors that cause inconsistencies in diversity-Disturbance relationships. The ecological threshold can extend its utility in rangeland management because it also has the compatibility with the maintenance of species diversity. This study thus suggests that some Intermediate scales of grazing and ecological thresholds are mutually supportive tools for sustainable management of Mongolian rangelands.
Takehiro Sasaki - One of the best experts on this subject based on the ideXlab platform.
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management applicability of the Intermediate Disturbance Hypothesis across mongolian rangeland ecosystems
Ecological Applications, 2009Co-Authors: Takehiro Sasaki, Satoru Okubo, Tomoo Okayasu, Undarmaa Jamsran, Toshiya Ohkuro, Kazuhiko TakeuchiAbstract:The current growing body of evidence for diversity–Disturbance relationships suggests that the peaked pattern predicted by the Intermediate Disturbance Hypothesis (IDH) may not be the rule. Even if ecologists could quantify the diversity–Disturbance relationship consistent with the IDH, the applicability of the IDH to land management has rarely been addressed. We examined two hypotheses related to the generality and management applicability of the IDH to Mongolian rangeland ecosystems: that the diversity–Disturbance relationship varies as a function of landscape condition and that some Intermediate scales of grazing can play an important role in terms of sustainable rangeland management through a grazing gradient approach. We quantified the landscape condition of each ecological site using an ordination technique and determined two types of landscape conditions: relatively benign and harsh environmental conditions. At the ecological sites characterized by relatively benign environmental conditions, divers...
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management applicability of the Intermediate Disturbance Hypothesis across mongolian rangeland ecosystems
Ecological Applications, 2009Co-Authors: Takehiro Sasaki, Satoru Okubo, Tomoo Okayasu, Undarmaa Jamsran, Toshiya Ohkuro, Kazuhiko TakeuchiAbstract:The current growing body of evidence for diversity-Disturbance relationships suggests that the peaked pattern predicted by the Intermediate Disturbance Hypothesis (IDH) may not be the rule. Even if ecologists could quantify the diversity-Disturbance relationship consistent with the IDH, the applicability of the IDH to land management has rarely been addressed. We examined two hypotheses related to the generality and management applicability of the IDH to Mongolian rangeland ecosystems: that the diversity-Disturbance relationship varies as a function of landscape condition and that some Intermediate scales of grazing can play an important role in terms of sustainable rangeland management through a grazing gradient approach. We quantified the landscape condition of each ecological site using an ordination technique and determined two types of landscape conditions: relatively benign and harsh environmental conditions. At the ecological sites characterized by relatively benign environmental conditions, diversity-Disturbance relationships were generally consistent with the IDH, and maximum diversity was observed at some Intermediate distance from the source of the grazing gradient. In contrast, the IDH was not supported at most (but not all) sites characterized by relatively harsh environmental conditions. The Intermediate levels of grazing were generally located below the ecological threshold representing the points or zones at which Disturbance should be limited to prevent drastic changes in ecological conditions, suggesting that there is little "conundrum" with regard to Intermediate Disturbance in the studied systems in terms of land management. We suggest that the landscape condition is one of the primary factors that cause inconsistencies in diversity-Disturbance relationships. The ecological threshold can extend its utility in rangeland management because it also has the compatibility with the maintenance of species diversity. This study thus suggests that some Intermediate scales of grazing and ecological thresholds are mutually supportive tools for sustainable management of Mongolian rangelands.
Douglas Sheil - One of the best experts on this subject based on the ideXlab platform.
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defining and defending connell s Intermediate Disturbance Hypothesis a response to fox
Trends in Ecology and Evolution, 2013Co-Authors: Douglas Sheil, David F R P BurslemAbstract:In his recent Opinion article in TREE, Jeremy Fox [1] finds that evidence for the Intermediate Disturbance Hypothesis (IDH) appears mixed and shows that some explanations linking Disturbance to species coexistence are flawed. Based on this, he argues that we should abandon the IDH. Whereas we agree with his observations, we reject his conclusions. Fox's criticisms are misdirected because the ideas that he disputes are distinct from the authentic IDH. Although we acknowledge its vulnerability to misinterpretation and misrepresentation, Connell's IDH remains valid and useful.
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tropical forest diversity environmental change and species augmentation after the Intermediate Disturbance Hypothesis
Journal of Vegetation Science, 1999Co-Authors: Douglas SheilAbstract:It is not simple to predict how environmental changes may impact tropical forest species diversity. Published hy- potheses are almost invariably too incomplete, too poorly specified and too dependent upon unrealistic assumptions to be useful. Ecologists have sought theoretical simplicity, and while this has provided many elegant abstract concepts, it has hindered the attainment of more practical goals. The problem is not how to judge the individual hypotheses and arguments, but rather how to build upon and combine the many hard-won facts and principles into an integrated science. Controversy is inevitable when the assumptions, defini- tions and applications of a given Hypothesis are unclear. Elegance, as an end in itself, has too often been used to justify abstract simplification and a lack of operational definition. Clarifying and combining hypotheses while avoiding assump- tions provides a potentially more useful, if less elegant, stand- point. An appraisal of Connell's Intermediate Disturbance Hypothesis, and its application to long-term observations from a Ugandan forest illustrates these concerns. Current emphases encourage ecologists to exclude consideration of environmental instability and non-pristine ecosystems. In reality, many environmental changes and eco- logical processes contribute to both the accumulation and erosion of diversity, at all spatial and temporal scales. Site histories, contexts, long-term processes, species-pool dyna- mics, and the role of people require greater emphasis. These considerations reveal that many environmental changes, even those associated with degradation, can lead to a transient rise in species densities. Drawing on related studies, such as forest yield prediction, suggests that the formulation and calibration of simulation models provides the most tractable means to address the complexity of real vegetation. Simulation-based approaches will become increasingly useful both in unifying the study of vegetation dynamics and in providing improved predictive capacity. Quantification of the processes, scales and sensitivities of the dynamics of tropical forest communities remains a major challenge.
Trejsi Decolli - One of the best experts on this subject based on the ideXlab platform.
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long term bio cultural heritage exploring the Intermediate Disturbance Hypothesis in agro ecological landscapes mallorca c 1850 2012
Biodiversity and Conservation, 2015Co-Authors: Joan Marull, Enric Tello, Nofre Fullana, Ivan Murray, Gabriel Jover, Carme Font, Francesc Coll, Elena Domene, Veronica Leoni, Trejsi DecolliAbstract:We applied an Intermediate Disturbance-complexity approach to the land-use change of cultural landscapes in the island of Mallorca from c. 1850 to the present, which accounts for the joint behaviour of human appropriation of photosynthetic capacity used as a measure of Disturbance, and a selection of land metrics at different spatial scales that account for ecological functionality as a proxy of biodiversity. We also delved deeper into local land-use changes in order to identify the main socioeconomic drivers and ruling agencies at stake. A second degree polynomial regression was obtained linking socio-metabolic Disturbance and landscape ecological functioning (jointly assessing landscape patterns and processes). The results confirm our Intermediate Disturbance-complexity Hypothesis by showing a hump-shaped relationship where the highest level of landscape complexity (heterogeneity connectivity) is attained when Disturbance peaks at 50–60 %. The study proves the usefulness of transferring the concept of Intermediate Disturbance to Mediterranean cultural landscapes, and suggests that the conservation of heterogeneous and well connected land-use mosaics with a positive interplay between Intermediate level of farming Disturbances and land-cover complexity endowed with a rich bio-cultural heritage will preserve a wildlife-friendly agro-ecological matrix that is likely to house high biodiversity.
Ulrich Sommer - One of the best experts on this subject based on the ideXlab platform.
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Intermediate Disturbance Hypothesis in phytoplankton ecology proceedings of the 8th workshop of the international association of phytoplankton taxonomy and ecology held in baja hungary 5 15 july 1991
Padisak J. Reynolds C. S. and Sommer Ulrich eds. (1993) Intermediate disturbance hypothesis in phytoplankton ecology : proceedings of the 8th workshop, 1993Co-Authors: J Padisak, C S Reynolds, Ulrich SommerAbstract:Foreword. Hutchinson's heritage: the diversity-Disturbance relationship in phytoplankton U. Sommer, J. Padisak, C.S. Reynolds, P. Juhasz-Nagy. Disturbance events affecting phytoplankton biomass, composition and species diversity in a shallow, eutrophic, temperate lake B.A. Jacobsen, P. Simonsen. Stress and Disturbance in the phytoplankton community of a shallow hypertrophic lake K. Olrik, A. Nauwerck. Diversity and succession of the phytoplankton in a small lake over a two-year period P. Eloranta. Phytoplankton succession and diversity in a warm monomictic, relatively shallow lake: Lake Volvi, Macedonia, Greece M. Moustaka-Gouni. Hypertrophic phytoplankton and the Intermediate Disturbance Hypothesis C. Rojo, M. Alvarez-Cobelas. Disturbance-diversity relationships in two lakes of similar nutrient chemistry but contrasting Disturbance regimes U. Sommer. Importance of Intermediate Disturbances for species composition and diversity of phytoplankton in two very different Berlin lakes I. Chorus, G. Schlag. Seasonal succession of phytoplankton and its diversity in two highly eutrophic lakes with different conditions of stratification I. Trifonova. Seasonal fluctuations in the diversity and compositional stability of phytoplankton communities in small lakes in upper Bavaria R. Holzmann. Ecology of the phytoplankton of the River Moselle: effects of Disturbances on community structure and diversity J.-P. Descy. Some notes about the Intermediate Disturbance Hypothesis and its effects on the phytoplankton of the middle Orinoco river H.I. Carvayal-Chitty. Effects of the water discharge on periphyton abundance and diversity in a large river (River Danube, Hungary) E. Acs, K.T. Kiss. The influence of different Disturbance frequencies on the species richness, diversityand equitability of phytoplankton in shallow lakes J. Padisak. Scales of Disturbance and their role in plankton ecology C.S. Reynolds. Notes on compositional diversity P. Juhasz-Nagy. Intermediate Disturbance in the ecology of phytoplankton and the maintenance of species diversity: a synthesis C.S. Reynolds, U. Sommer, J. Padisak. General index.
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Intermediate Disturbance in the ecology of phytoplankton and the maintenance of species diversity a synthesis
Hydrobiologia, 1993Co-Authors: C S Reynolds, J Padisak, Ulrich SommerAbstract:This paper concludes a collection of contributions presented at the 8th Workshop of the International Association of Phytoplankton Taxonomy and Ecology. It derives a consensus as to the virtues and strengths of J. H. Connell’s Intermediate Disturbance Hypothesis (IDH), its applicability to phytoplankton ecology and its theoretical and practical weaknesses. The view is expressed that the IDH is too useful a concept to reject and that, as a word model, it provides a powerful link between diversity and Disturbance. The more robust investigations that are necessary to consolidate the tenancy of IDH need to concentrate upon the separation and quantification of the stimulus- and response-components of Disturbance.
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hutchinson s heritage the diversity Disturbance relationship in phytoplankton
Hydrobiologia, 1993Co-Authors: Ulrich Sommer, C S Reynolds, J Padisak, P JuhasznagyAbstract:This paper introduces a collection of contributions presented at the 8th Workshop of the International Association of Phytoplankton Taxonomy and Ecology. It compares the substance of with what to limnologists is the more familiar ‘paradox of the plankton’ posed by G. E. Hutchinson. The utility of Connell‘s Intermediate Disturbance Hypothesis in plankton ecology is, potentially, more instructive but inherent difficulties in relating response to stimulus have to be overcome. A copy of the brief distributed to contributors before the workshop is appended.