The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Ronald Baker - One of the best experts on this subject based on the ideXlab platform.
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trophic ecology of large predatory reef fishes energy pathways trophic level and implications for fisheries in a Changing Climate
Marine Biology, 2014Co-Authors: Ashley J. Frisch, Matthew Ireland, Ronald BakerAbstract:Large predatory fishes are disproportionately targeted by reef fisheries, but little is known about their trophic ecology, which inhibits understanding of community dynamics and the potential effects of Climate change. In this study, stable isotope analyses were used to infer trophic ecology of a guild of large predatory fishes that are targeted by fisheries on the Great Barrier Reef, Australia. Each of four focal predators (Plectropomus leopardus, Plectropomus maculatus, Lethrinus miniatus and Lutjanus carponotatus) was found to have a distinct isotopic signature in terms of δ13C and δ15N. A two-source mixing model (benthic reef-based versus pelagic) indicated that P. leopardus and L. miniatus derive the majority (72 and 62 %, respectively) of their production from planktonic sources, while P. maculatus and L. carponotatus derive the majority (89 and 74 %, respectively) of their production from benthic reef-based sources. This indicates that planktonic production is important for sustaining key species in reef fisheries and highlights the need for a whole-ecosystem approach to fisheries management. Unexpectedly, there was little isotopic niche overlap between three of four focal predators, suggesting that inter-specific competition for prey may be low or absent. δ15Nitrogen indicated that the closely related P. leopardus and P. maculatus are apex predators (trophic level > 4), while δ13C indicated that each species has a different diet and degree of trophic specialisation. In view of these divergent trophic ecologies, each of the four focal predators (and the associated fisheries) are anticipated to be differentially affected by Climate-induced disturbances. Thus, the results presented herein provide a useful starting point for precautionary management of exploited predator populations in a Changing Climate.
Julie R. Etterson - One of the best experts on this subject based on the ideXlab platform.
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Evolutionary responses to Changing Climate
Ecology, 2005Co-Authors: Margaret B. Davis, Ruth G Shaw, Julie R. EttersonAbstract:Until now, Quaternary paleoecologists have regarded evolution as a slow process relative to Climate change, predicting that the primary biotic response to Changing Climate is not adaptation, but instead (1) persistence in situ if Changing Climate remains within the species' tolerance limits, (2) range shifts (migration) to regions where Climate is currently within the species' tolerance limits, or (3) extinction. We argue here that all three of these outcomes involve evolutionary processes. Genetic differentiation within species is ubiquitous, commonly via adaptation of populations to differing environmental conditions. Detectable adaptive divergence evolves on a time scale comparable to change in Climate, within decades for herbaceous plant species, and within centuries or millennia for longer-lived trees, implying that biologically significant evolutionary response can accompany temporal change in Climate. Models and empirical studies suggest that the speed with which a population adapts to a Changing environment affects invasion rate of new habitat and thus migration rate, population growth rate and thus probability of extinction, and growth and mortality of individual plants and thus productivity of regional vegetation. Recent models and experiments investigate the stability of species tolerance limits, the influence of environmental gradients on marginal populations, and the interplay of demography, gene flow, mutation rate, and other genetic processes on the rate of adaptation to changed environments. New techniques enable ecologists to document adaptation to Changing conditions directly by resurrecting ancient populations from propagules buried in decades-old sediment. Improved taxonomic resolution from morphological studies of macrofossils and DNA recovered from pollen grains and macroremains provides additional information on range shifts, changes in population sizes, and extinctions. Collaboration between paleoecologists and evolutionary biologists can refine interpretations of paleorecords, and improve predictions of biotic response to anticipated Climate change.
Raja K Reddy - One of the best experts on this subject based on the ideXlab platform.
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impacts of Changing Climate and Climate variability on seed production and seed industry
Advances in Agronomy, 2013Co-Authors: Rishi P Singh, P Vara V Prasad, Raja K ReddyAbstract:Abstract Agriculture is extremely sensitive to Climate and weather conditions. The resilience of our crop production systems to changes in Climate can be enhanced by improved understanding impacts and responses of crops to Changing Climates. Several countries in Asia and Africa are at the risk of losing about 280 million tons of potential cereal production as a result of Climate change factor, particularly increasing temperatures and prolonged dry periods. The most significant negative changes for developing countries in Asia, where agricultural production declines of about −4% to −10% are anticipated under different socioeconomic and Climate change scenarios. Rising temperatures will reduce the amount of fertile farmland, and by 2050, the amount of maize grown is expected to decline by 6–23% and wheat by 40–45%. The majority of the world’s food supply comes from the consumption of seeds from grain crops (wheat, rice, maize, soybean, barley, and sorghum), which are most vulnerable to Changing Climates. The growth in food production is lower than the population growth; therefore, there will be challenges of food security. Major impacts of Climate change will be on rain-fed crops that account for nearly 60% of cropland area. As predicted, South Asia and sub-Saharan Africa will be highly vulnerable to Climate change. Crop production can be increased by the use of quality seeds of high-yielding stress-tolerant varieties, combined with judicious use of inputs, particularly water and nutrients. Climate changes affect all four dimensions of food security, that is, availability, access to food, stability of food supplies, and food utilization. The seed industry plays an important role in increasing food production. It provides high-quality seeds of high-yielding varieties in adequate quantities at the right time and right place. Climate change influences the population dynamics of insects, emergence of new pests, Changing status of pest and disease development, and evolution of new races of pests. Quality seed production is also affected by crop/weed interactions, loss of pollinator biodiversity, and genetic diversity. The seed crop is also affected by Climate change regarding change in crop phenology, reproduction, flowering, anthesis/pollen viability, and pollination/fertilization, length of seed-filling duration, seed setting, seed size, seed dormancy, seed yield, and ultimately seed quality. Therefore, the cost of seed production is likely to increase in Changing Climate due to scheduling of operations, land and water management, herbicide/insecticide applications, pollination management, and postharvest seed management. Issues regarding intellectual property rights (IPR) related to seed, including patent infringements, prevalence of monocultures, consolidations of transnational corporations through acquisitions and mergers, and biodiversity and pollinator-loss related issues further complicate the problem. The lack of trained conventional plant breeders, crop physiologists, and seed technologists and stronger interdisciplinary collaboration between agronomists and biologists need attention. Further, acceptance of engineered crop or seed, increasing cost of genetically engineered (GE) seed as compared with conventional seed with no yield advantage, increasing number of herbicide applications, culminate in loss in net farm income in developed countries. In this article, the issues regarding the impact of Climate change (particularly increasing temperature and carbon dioxide concentrations) on seed production, the present trend of the global seed industry, are discussed.
Ulrich Sommer - One of the best experts on this subject based on the ideXlab platform.
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Phytoplankton response to a Changing Climate
Hydrobiologia, 2012Co-Authors: Monika Winder, Ulrich SommerAbstract:Phytoplankton are at the base of aquatic food webs and of global importance for ecosystem functioning and services. The dynamics of these photosynthetic cells are linked to annual fluctuations of temperature, water column mixing, resource availability, and consumption. Climate can modify these environmental factors and alter phytoplankton structure, seasonal dynamics, and taxonomic composition. Here, we review mechanistic links between Climate alterations and factors limiting primary production, and highlight studies where Climate change has had a clear impact on phytoplankton processes. Climate affects phytoplankton both directly through physiology and indirectly by Changing water column stratification and resource availability, mainly nutrients and light, or intensified grazing by heterotrophs. These modifications affect various phytoplankton processes, and a widespread advance in phytoplankton spring bloom timing and Changing bloom magnitudes have both been observed. Climate warming also affects phytoplankton species composition and size structure, and favors species traits best adapted to Changing conditions associated with Climate change. Shifts in phytoplankton can have far-reaching consequences for ecosystem structure and functioning. An improved understanding of the mechanistic links between Climate and phytoplankton dynamics is important for predicting Climate change impacts on aquatic ecosystems.
Fikret Berkes - One of the best experts on this subject based on the ideXlab platform.
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rethinking social contracts building resilience in a Changing Climate
Ecology and Society, 2009Co-Authors: Karen Obrien, Bronwyn Hayward, Fikret BerkesAbstract:Social contracts play an important role in defining the reciprocal rights, obligations, and responsibilities between states and citizens. Climate change is creating new challenges for both states and citizens, inevitably forcing a rethinking of existing and evolving social contracts. In particular, the social arrangements that enhance the well-being and security of both present and future generations are likely to undergo dramatic transformations in response to ecosystem changes, more extreme weather events, and the consequences of social-ecological changes in distant locations. The types of social contracts that evolve in the face of a Changing Climate will have considerable implications for adaptation policies and processes. We consider how a resilience approach can contribute to new social contracts in the face of uncertainty and change. Examples from Norway, New Zealand, and Canada show how resilience thinking provides a new way of looking at social contracts, emphasizing the dynamics, links, and complexity of coupled social- ecological systems. Resilience thinking provides valuable insights on the characteristics of a new social contract, and social contract theory provides some insights on creating resilience and human security in a warming world.
