Community secondary production as a measure of ecosystem
... survey. Fish densities and lengths in each random area were then estimated with 1-m 2 visualized quadrats using underwater visual census (UVC, Valentine-Rose et al. 2007b). Surveys were taken within 2 hrs of low tide to facilitate estimates of fish biomass, because fishes were constricted to the mai ...
... survey. Fish densities and lengths in each random area were then estimated with 1-m 2 visualized quadrats using underwater visual census (UVC, Valentine-Rose et al. 2007b). Surveys were taken within 2 hrs of low tide to facilitate estimates of fish biomass, because fishes were constricted to the mai ...
Fish Community Objectives for Lake Michigan
... Of all the inshore areas of the lake, the most-productive fish communities probably existed in southern Green Bay, other shallow embayments, and in estuaries of large rivers. Green Bay was also an important spawning ground and nursery area for lake herring in what otherwise is classified as a percid ...
... Of all the inshore areas of the lake, the most-productive fish communities probably existed in southern Green Bay, other shallow embayments, and in estuaries of large rivers. Green Bay was also an important spawning ground and nursery area for lake herring in what otherwise is classified as a percid ...
2007-2008 - Illinois Natural History Survey
... Collection-based studies remain a core area of research at INHS. Its world-renowned collections both reflect and support the active roles that our scientists continue to play in efforts to improve knowledge of Earth’s biological diversity. The INHS biological collections, assembled by Survey scienti ...
... Collection-based studies remain a core area of research at INHS. Its world-renowned collections both reflect and support the active roles that our scientists continue to play in efforts to improve knowledge of Earth’s biological diversity. The INHS biological collections, assembled by Survey scienti ...
Advice to the Minister for Sustainability, Environment, Water
... The olive perchlet (also known as Agassiz's glassfish) is historically known from the MurrayDarling system in South Australia, Victoria, western New South Wales and southern Queensland. The species is also known from coastal drainages of New South Wales and Queensland between Lake Hiawatha (NSW) and ...
... The olive perchlet (also known as Agassiz's glassfish) is historically known from the MurrayDarling system in South Australia, Victoria, western New South Wales and southern Queensland. The species is also known from coastal drainages of New South Wales and Queensland between Lake Hiawatha (NSW) and ...
Dabbling Ducks - University of Maryland Extension
... the western counties are forced toward the remaining open water of larger rivers and the Chesapeake Bay. Concentrations of large numbers of waterfowl during spring migration are not as dramatic as in the fall. At that time of year, most species migrate north over a longer, protracted period of time ...
... the western counties are forced toward the remaining open water of larger rivers and the Chesapeake Bay. Concentrations of large numbers of waterfowl during spring migration are not as dramatic as in the fall. At that time of year, most species migrate north over a longer, protracted period of time ...
bakersfield cactus - Bakersfield Habitat Conservation Plan
... Dr. Ellen Cypher and her husband Dr. Brian Cypher have led conservation efforts to help restore new populations of the cactus. They have seen firsthand the damage caused by dumping, trespassing and offroad vehicle use. Because almost all of the known sites are on private land, the couple would like ...
... Dr. Ellen Cypher and her husband Dr. Brian Cypher have led conservation efforts to help restore new populations of the cactus. They have seen firsthand the damage caused by dumping, trespassing and offroad vehicle use. Because almost all of the known sites are on private land, the couple would like ...
Organisms and food webs in rock pools
... 1987). This is common among zooplankton and many other groups of rock pool species (Ranta 1982). Water insects (imagines) and gammarids may escape when conditions deteriorate while other species survive drought or freezing in the sediments. Other adaptations to unpredictable habitats are short life ...
... 1987). This is common among zooplankton and many other groups of rock pool species (Ranta 1982). Water insects (imagines) and gammarids may escape when conditions deteriorate while other species survive drought or freezing in the sediments. Other adaptations to unpredictable habitats are short life ...
DISTRIBUTION AND STATUS OF AUSTRALIAN WATER
... A major problem in investigating the status and distribution of water-rat populations relates to limitations in live-trapping techniques. Most surveys have relied on the use of cage traps positioned on the water’s edge. Because the water-rat spends much of its time in the water and is an alert and i ...
... A major problem in investigating the status and distribution of water-rat populations relates to limitations in live-trapping techniques. Most surveys have relied on the use of cage traps positioned on the water’s edge. Because the water-rat spends much of its time in the water and is an alert and i ...
Stable isotopes as trophic tracers: combining field sampling and
... a food source for (surface) deposit feeders. Despite the clearly demonstrated resuspension of benthic algae at high current velocities, suspension feeders appeared to depend almost exclusively on pelagic algae (and possibly detrital carbon) as a food source. Based on the results of the experiments, ...
... a food source for (surface) deposit feeders. Despite the clearly demonstrated resuspension of benthic algae at high current velocities, suspension feeders appeared to depend almost exclusively on pelagic algae (and possibly detrital carbon) as a food source. Based on the results of the experiments, ...
Species and population differences in social recognition between
... they use. Specific individual recognition is gradually learned over a period of time (Griffiths and Magurran 1997a), and there is an upper limit to the number of different individuals that can be memorized (Griffiths and Magurran 1997b). Contrastingly, the more general form of recognition does not r ...
... they use. Specific individual recognition is gradually learned over a period of time (Griffiths and Magurran 1997a), and there is an upper limit to the number of different individuals that can be memorized (Griffiths and Magurran 1997b). Contrastingly, the more general form of recognition does not r ...
Fisheries catches and the carrying capacity of marine ecosystems in
... The carrying capacity of marine shelf ecosystems in southern Brazil for harvestable species is analyzed by (1) quantifying the amount of available primary production appropriated by ®sheries catches, (2) evaluating the trend in the mean trophic level of ®sheries, and (3) simulating the ecosystem eff ...
... The carrying capacity of marine shelf ecosystems in southern Brazil for harvestable species is analyzed by (1) quantifying the amount of available primary production appropriated by ®sheries catches, (2) evaluating the trend in the mean trophic level of ®sheries, and (3) simulating the ecosystem eff ...
Conservation biology
... • In addition to transporting nutrients from one location to another, humans have added new materials, some of them toxins, to ecosystems • Harvest of agricultural crops exports nutrients from the agricultural ecosystem • Agriculture leads to the depletion of nutrients in the soil • Fertilizers add ...
... • In addition to transporting nutrients from one location to another, humans have added new materials, some of them toxins, to ecosystems • Harvest of agricultural crops exports nutrients from the agricultural ecosystem • Agriculture leads to the depletion of nutrients in the soil • Fertilizers add ...
Reprint - Queen`s University Department of Mathematics and Statistics.
... called “character displacement”because it should result in phenotypic characters related to resource use in similar species being displaced from one another where their geographic ranges overlap. Indeed, Brown and Wilson (1956) put forward a number of empirical examples to support this idea (see Gra ...
... called “character displacement”because it should result in phenotypic characters related to resource use in similar species being displaced from one another where their geographic ranges overlap. Indeed, Brown and Wilson (1956) put forward a number of empirical examples to support this idea (see Gra ...
Predator effects on faunal community composition in
... Much emphasis has been placed on predator effects that cascade through food webs. Such top-down effects seem to be most common in systems with relatively simple food chains, and rarer in species-rich systems where numerous weak interactions among species can buffer strong top-down effects. Seagrass ...
... Much emphasis has been placed on predator effects that cascade through food webs. Such top-down effects seem to be most common in systems with relatively simple food chains, and rarer in species-rich systems where numerous weak interactions among species can buffer strong top-down effects. Seagrass ...
Character Convergence under Competition for Nutritionally
... (an evolutionarily stable strategy [ESS] that is also an evolutionary attractor). Changes in the CSS per capita consumption rates in response to changes in resource availability imply character convergence when changes in resource availability are assumed to arise from resource consumption by a (non ...
... (an evolutionarily stable strategy [ESS] that is also an evolutionary attractor). Changes in the CSS per capita consumption rates in response to changes in resource availability imply character convergence when changes in resource availability are assumed to arise from resource consumption by a (non ...
Beyond species loss: the extinction of ecological interactions in a
... We define an axis of habitat loss (x) that ranges from a pristine, undisturbed stage (zero) to a stage (one) of complete disturbance where all species present in the zero stage have lost their habitat. This axis may represent a reversed area axis, widely used to indirectly predict extinction rates wi ...
... We define an axis of habitat loss (x) that ranges from a pristine, undisturbed stage (zero) to a stage (one) of complete disturbance where all species present in the zero stage have lost their habitat. This axis may represent a reversed area axis, widely used to indirectly predict extinction rates wi ...
Beyond species loss: The extinction of ecological
... We define an axis of habitat loss (x) that ranges from a pristine, undisturbed stage (zero) to a stage (one) of complete disturbance where all species present in the zero stage have lost their habitat. This axis may represent a reversed area axis, widely used to indirectly predict extinction rates wi ...
... We define an axis of habitat loss (x) that ranges from a pristine, undisturbed stage (zero) to a stage (one) of complete disturbance where all species present in the zero stage have lost their habitat. This axis may represent a reversed area axis, widely used to indirectly predict extinction rates wi ...
Effects of fisheries closure size, age, and history of compliance on
... were examined rather than control-impact relationships between closures and fished areas. Hence, the effect of closure compliance, size, and age were examined while simultaneously assessing the influence of habitat and geography within the closure. The current geographic distribution of coral reef s ...
... were examined rather than control-impact relationships between closures and fished areas. Hence, the effect of closure compliance, size, and age were examined while simultaneously assessing the influence of habitat and geography within the closure. The current geographic distribution of coral reef s ...
Spatial variation and effects of habitat on temperate reef fish
... (Fig. 1). These included, from South to North, Hahei (36j50.86VS, 175j49.32VE), Leigh (36j17.43VS, 174j48.82VE), Home Point (35j19.38VS, 174j21.38VE) and Berghan Point (34j55.78VS, 173j32.72VE) (Fig. 1). Within each location, fish were sampled at each of four different randomly located sites, separa ...
... (Fig. 1). These included, from South to North, Hahei (36j50.86VS, 175j49.32VE), Leigh (36j17.43VS, 174j48.82VE), Home Point (35j19.38VS, 174j21.38VE) and Berghan Point (34j55.78VS, 173j32.72VE) (Fig. 1). Within each location, fish were sampled at each of four different randomly located sites, separa ...
Linking Biodiversity and Ecosystem Services: Current
... directly on them, and well over $300 billion is generated from the annual trade of forest products (FAO 2010). Assessments of the effects of increased tree species richness on timber production are hindered by the difficulties of manipulating large, long-lived organisms (but see the TreeDivNet Web s ...
... directly on them, and well over $300 billion is generated from the annual trade of forest products (FAO 2010). Assessments of the effects of increased tree species richness on timber production are hindered by the difficulties of manipulating large, long-lived organisms (but see the TreeDivNet Web s ...
The Extinction of the Glaucus Macaw
... specialized mechanical device they work best at opening nuts of a small range of sizes. Hyacinth macaws prefer to eat palm seeds that are slightly smaller than the width of the hard cutting surface of their lower mandibles. By measuring the chisel width of museum specimens of Glaucus Macaws, Yamashi ...
... specialized mechanical device they work best at opening nuts of a small range of sizes. Hyacinth macaws prefer to eat palm seeds that are slightly smaller than the width of the hard cutting surface of their lower mandibles. By measuring the chisel width of museum specimens of Glaucus Macaws, Yamashi ...
Trait and density mediated indirect interactions in simple
... effects that emerge when species of top predators influence the abundance of species in non-adjacent lower levels of food webs through direct interactions with their prey species / called a trophic cascade. The second module involves interactions that occur when two resources, that do not interact ...
... effects that emerge when species of top predators influence the abundance of species in non-adjacent lower levels of food webs through direct interactions with their prey species / called a trophic cascade. The second module involves interactions that occur when two resources, that do not interact ...
Biotic and abiotic components - Pearson Schools and FE Colleges
... species may decline or they may have to switch food source. Similarly, seals will have to rely more on herring, possibly reducing their numbers or they may also have to switch food source. The amount of zooplankton may increase, improving food supply for jellyfish and herring. An estimated 1000 kg o ...
... species may decline or they may have to switch food source. Similarly, seals will have to rely more on herring, possibly reducing their numbers or they may also have to switch food source. The amount of zooplankton may increase, improving food supply for jellyfish and herring. An estimated 1000 kg o ...
Overexploitation
Overexploitation, also called overharvesting, refers to harvesting a renewable resource to the point of diminishing returns. Sustained overexploitation can lead to the destruction of the resource. The term applies to natural resources such as: wild medicinal plants, grazing pastures, game animals, fish stocks, forests, and water aquifers.In ecology, overexploitation describes one of the five main activities threatening global biodiversity. Ecologists use the term to describe populations that are harvested at a rate that is unsustainable, given their natural rates of mortality and capacities for reproduction. This can result in extinction at the population level and even extinction of whole species. In conservation biology the term is usually used in the context of human economic activity that involves the taking of biological resources, or organisms, in larger numbers than their populations can withstand. The term is also used and defined somewhat differently in fisheries, hydrology and natural resource management.Overexploitation can lead to resource destruction, including extinctions. However it is also possible for overexploitation to be sustainable, as discussed below in the section on fisheries. In the context of fishing, the term overfishing can be used instead of overexploitation, as can overgrazing in stock management, overlogging in forest management, overdrafting in aquifer management, and endangered species in species monitoring. Overexploitation is not an activity limited to humans. Introduced predators and herbivores, for example, can overexploit native flora and fauna.