In situ conservation methods - Forest Genetic Resources Training
... It is commonly agreed today that the big challenge in using and developing in situ methods, however, is to expand our vision of protected areas to include multiple use reserves (see p. 513 ff., this volume) and even to integrate conservation of genetic resources into the production system of modern ...
... It is commonly agreed today that the big challenge in using and developing in situ methods, however, is to expand our vision of protected areas to include multiple use reserves (see p. 513 ff., this volume) and even to integrate conservation of genetic resources into the production system of modern ...
The ecological consequences of habitat fragmentation
... that habitat fragmentation has a negligible effect on biodiversity after habitat amount is taken into account represents a striking paradox when placed alongside the many thousands of studies showing strong ecological effects of patch area, isolation, edge effects and other factors. Reconciling this ...
... that habitat fragmentation has a negligible effect on biodiversity after habitat amount is taken into account represents a striking paradox when placed alongside the many thousands of studies showing strong ecological effects of patch area, isolation, edge effects and other factors. Reconciling this ...
Abstracts -- file - Freshwater Mollusk Conservation Society
... need of conservation (Neves et al. 1997). For example, 42 of the 96 recent extinctions of freshwater mollusks have occurred in the Coosa River basin. The highly endemic spring snails (Hydrobiidae) of the West also contribute a host of species in jeopardy of extinction. With so few specialists on th ...
... need of conservation (Neves et al. 1997). For example, 42 of the 96 recent extinctions of freshwater mollusks have occurred in the Coosa River basin. The highly endemic spring snails (Hydrobiidae) of the West also contribute a host of species in jeopardy of extinction. With so few specialists on th ...
The Extinction of Endemic Species by a Program of
... The giant African snail, Achatina fulica fulica on Moorea since 1978:-1979 cannot Bowdich, is well known as an agricultural pest rigorously be ascribed to the effects of (Mead 1961, 1979). It was introduced into Euglandina rosea. Living A chatina are still to Tahiti (by someone who wished to breed i ...
... The giant African snail, Achatina fulica fulica on Moorea since 1978:-1979 cannot Bowdich, is well known as an agricultural pest rigorously be ascribed to the effects of (Mead 1961, 1979). It was introduced into Euglandina rosea. Living A chatina are still to Tahiti (by someone who wished to breed i ...
the maintenance of species diversity by disturbance
... disrupted by a disturbance. Predation may create small patches within a sampled area; catastrophic events usually cover areas much larger than sampling plots. Thus the sampled area may be either totally contained within a single patch or composed of many patches. The patch affected by a disturbance ...
... disrupted by a disturbance. Predation may create small patches within a sampled area; catastrophic events usually cover areas much larger than sampling plots. Thus the sampled area may be either totally contained within a single patch or composed of many patches. The patch affected by a disturbance ...
Day 10
... Extinction and extirpation occur naturally (cont’d) • Earth has experienced five previous mass extinction episodes • In the past 440 million years, mass extinctions have eliminated at least 50% of all species • Today’s mass extinction is caused by humans and humans will suffer as a result of it ...
... Extinction and extirpation occur naturally (cont’d) • Earth has experienced five previous mass extinction episodes • In the past 440 million years, mass extinctions have eliminated at least 50% of all species • Today’s mass extinction is caused by humans and humans will suffer as a result of it ...
Network ecology: topological constraints on ecosystem dynamics
... By the end of the seventies, a collection of food web patterns statistically characteristic in nature have been produced (25; 127; 129; 132). (Some concepts in this paragraph will be defined and explained later.) First, it was argued that food chains are seldom longer than four or five steps, for va ...
... By the end of the seventies, a collection of food web patterns statistically characteristic in nature have been produced (25; 127; 129; 132). (Some concepts in this paragraph will be defined and explained later.) First, it was argued that food chains are seldom longer than four or five steps, for va ...
Biodiversity, Stability, and Productivity in Competitive Communities
... qualitative and quantitative. Pimm (1984, 1991), for instance, identified five alternative uses of the term, multiplied by three levels of complexity and three levels of organization—giving potentially 45 variations in the meaning of stability. Different meanings of stability can give different conc ...
... qualitative and quantitative. Pimm (1984, 1991), for instance, identified five alternative uses of the term, multiplied by three levels of complexity and three levels of organization—giving potentially 45 variations in the meaning of stability. Different meanings of stability can give different conc ...
Biotic interactions and speciation in the tropics
... static since abiotic factors do not coevolve. This argument assumes that speciation is a byproduct of ecological adaptation, either directly, e.g. habitat shifts or differences in mating preferences, or indirectly, due to the fixation of adaptive genes that contribute to hybrid incompatibilities. Th ...
... static since abiotic factors do not coevolve. This argument assumes that speciation is a byproduct of ecological adaptation, either directly, e.g. habitat shifts or differences in mating preferences, or indirectly, due to the fixation of adaptive genes that contribute to hybrid incompatibilities. Th ...
stochastic processes across scales Disentangling the importance of
... this topic, we emphasize that it is not our intent to develop an elegant mathematical or statistical model to advocate one approach over another. Our goal is simply to reinforce how stochastic ecological processes that emerge within and among regions can influence the importance of deterministic pro ...
... this topic, we emphasize that it is not our intent to develop an elegant mathematical or statistical model to advocate one approach over another. Our goal is simply to reinforce how stochastic ecological processes that emerge within and among regions can influence the importance of deterministic pro ...
Learning objectives
... 15. Explain why aquatic ecosystems may have inverted biomass pyramids. 16. Explain why worldwide agriculture could feed more people if all humans consumed only plant material. 17. Explain the green-world hypothesis. Describe four factors that may act to keep herbivores in check. The Cycling of Chemi ...
... 15. Explain why aquatic ecosystems may have inverted biomass pyramids. 16. Explain why worldwide agriculture could feed more people if all humans consumed only plant material. 17. Explain the green-world hypothesis. Describe four factors that may act to keep herbivores in check. The Cycling of Chemi ...
Disentangling the importance of ecological niches from stochastic
... communities are not saturated with species [7,82–84]. Likewise, local diversity is typically higher in metacommunities where dispersal rates among localities are more frequent relative to those with less-frequent dispersal [83]. Moreover, the extent to which propagule arrival influences species rich ...
... communities are not saturated with species [7,82–84]. Likewise, local diversity is typically higher in metacommunities where dispersal rates among localities are more frequent relative to those with less-frequent dispersal [83]. Moreover, the extent to which propagule arrival influences species rich ...
A Dynamical Systems Approach to Modeling Plankton Food Web
... Abstract The main focus of this project is modeling phytoplankton predator-prey ...
... Abstract The main focus of this project is modeling phytoplankton predator-prey ...
Modelling Food Webs
... noticed for the first time. During roughly the same period simple models of food webs were formulated. The first models were dynamic, using simple population dynamics, but without incorporating the evolved nature of the web. Static models were also introduced in which species were simply represented ...
... noticed for the first time. During roughly the same period simple models of food webs were formulated. The first models were dynamic, using simple population dynamics, but without incorporating the evolved nature of the web. Static models were also introduced in which species were simply represented ...
Evolution and the latitudinal diversity gradient
... present, punctuated by occasional periods of warm climate such as occurred in the middle Miocene (Wolfe 1975, 1978; Behrensmeyer et al. 1992; Zachos et al. 2001). The glacial– interglacial cycles during the Pleistocene represent the latest climatic perturbations that disproportionately affected spec ...
... present, punctuated by occasional periods of warm climate such as occurred in the middle Miocene (Wolfe 1975, 1978; Behrensmeyer et al. 1992; Zachos et al. 2001). The glacial– interglacial cycles during the Pleistocene represent the latest climatic perturbations that disproportionately affected spec ...
Inverse density dependence and the Allee effect
... eat the flour, but they also eat their own eggs as they encounter these on their travels’35. Because of this, eggs are less likely to escape oophagy at high densities. However, females lay more eggs, and eggs with a higher percentage of fertility, when they have been stimulated by successive copulat ...
... eat the flour, but they also eat their own eggs as they encounter these on their travels’35. Because of this, eggs are less likely to escape oophagy at high densities. However, females lay more eggs, and eggs with a higher percentage of fertility, when they have been stimulated by successive copulat ...
Newton`s Laws of Motion - Augusta Independent Schools
... Factors that Threaten Biodiversity The current high rate of extinction is due to the activities of a single species—Homo sapiens. Humans are changing conditions on Earth faster than new traits can evolve to cope with the new conditions. ...
... Factors that Threaten Biodiversity The current high rate of extinction is due to the activities of a single species—Homo sapiens. Humans are changing conditions on Earth faster than new traits can evolve to cope with the new conditions. ...
Modelling Food Webs Abstract 1 Introduction
... noticed for the first time. During roughly the same period simple models of food webs were formulated. The first models were dynamic, using simple population dynamics, but without incorporating the evolved nature of the web. Static models were also introduced in which species were simply represented ...
... noticed for the first time. During roughly the same period simple models of food webs were formulated. The first models were dynamic, using simple population dynamics, but without incorporating the evolved nature of the web. Static models were also introduced in which species were simply represented ...
A Case Study in Concept Determination: Ecological Diversity.
... to distinguish them from indices derived from parameters of statistical models of species abundance, such as the log series [Fisher et al., 1943] and log normal [Preston, 1948], or from biological models, such as the broken stick and overlapping niche model [MacArthur, 1957].2 Unlike parametric indi ...
... to distinguish them from indices derived from parameters of statistical models of species abundance, such as the log series [Fisher et al., 1943] and log normal [Preston, 1948], or from biological models, such as the broken stick and overlapping niche model [MacArthur, 1957].2 Unlike parametric indi ...
Chapter 12
... – many of which yielded the impressions – of a number of soft-bodied organisms – beautifully preserved on bedding planes ...
... – many of which yielded the impressions – of a number of soft-bodied organisms – beautifully preserved on bedding planes ...
Invasion in a heterogeneous world: resistance, coexistence or
... measure of impact at the community level is change in community membership, especially extinction of native species (e.g. number of native species driven to extinction). While it is easy to verify extinction in models, it can be problematic in empirical studies, and care must be taken to specify the ...
... measure of impact at the community level is change in community membership, especially extinction of native species (e.g. number of native species driven to extinction). While it is easy to verify extinction in models, it can be problematic in empirical studies, and care must be taken to specify the ...
The abstract booklet can be downloaded here
... patterns: a multi-‐scale study Modeling the distribution of plant communities of Moghra Oasis ...
... patterns: a multi-‐scale study Modeling the distribution of plant communities of Moghra Oasis ...
Discoveries of new mammal species and their
... patterns of species distribution were done using 10,000-km2 (2) grid cells, similar to our previous studies (10, 12, 13). The new mammal species we found were of three types. The first was morphologically distinct species found in previously poorly surveyed areas. The second, the result of using mol ...
... patterns of species distribution were done using 10,000-km2 (2) grid cells, similar to our previous studies (10, 12, 13). The new mammal species we found were of three types. The first was morphologically distinct species found in previously poorly surveyed areas. The second, the result of using mol ...
SudingMS_final_1007_RYS
... Werner 1983) and for functional traits (Goldberg 1990), it has been applied to ecosystem Although we discuss functional classification in terms of species and the grouping of species, it also applies to groupings at other levels of organization, such as genotypes or phenotypes of individuals acclima ...
... Werner 1983) and for functional traits (Goldberg 1990), it has been applied to ecosystem Although we discuss functional classification in terms of species and the grouping of species, it also applies to groupings at other levels of organization, such as genotypes or phenotypes of individuals acclima ...
... systems decreased as diversity increased. However, the accelerating effects of human activities on biodiversity and the possibility that the loss of biodiversity might impact ecosystem functioning (e.g., Ehrlich and Ehrlich 1981, Wilson 1992) renewed interest in the effects of diversity on ecosystem ...
Extinction
In biology and ecology, extinction is the end of an organism or of a group of organisms (taxon), normally a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and recover may have been lost before this point. Because a species' potential range may be very large, determining this moment is difficult, and is usually done retrospectively. This difficulty leads to phenomena such as Lazarus taxa, where a species presumed extinct abruptly ""reappears"" (typically in the fossil record) after a period of apparent absence.The age of the Earth is about 4.54 billion years old. The earliest undisputed evidence of life on Earth dates at least from 3.5 billion years ago, during the Eoarchean Era after a geological crust started to solidify following the earlier molten Hadean Eon. There are microbial mat fossils found in 3.48 billion-year-old sandstone discovered in Western Australia. Other early physical evidence of a biogenic substance is graphite in 3.7 billion-year-old metasedimentary rocks discovered in Western Greenland. More than 99 percent of all species, amounting to over five billion species, that ever lived on Earth are estimated to be extinct. Estimates on the number of Earth's current species range from 10 million to 14 million, of which about 1.2 million have been documented and over 86 percent have not yet been described.Through evolution, species arise through the process of speciation—where new varieties of organisms arise and thrive when they are able to find and exploit an ecological niche—and species become extinct when they are no longer able to survive in changing conditions or against superior competition. The relationship between animals and their ecological niches has been firmly established. A typical species becomes extinct within 10 million years of its first appearance, although some species, called living fossils, survive with virtually no morphological change for hundreds of millions of years. Mass extinctions are relatively rare events; however, isolated extinctions are quite common. Only recently have extinctions been recorded and scientists have become alarmed at the current high rate of extinctions. Most species that become extinct are never scientifically documented. Some scientists estimate that up to half of presently existing plant and animal species may become extinct by 2100.