Sentences with phrase «of predator populations»

Territoriality also dampens growth of predator populations, contributing to the lagged response of predator to prey population growth and allowing fluctuating prey populations time to recover from low density in systems with linked predator and prey population dynamics3, 6,7,8.

And their high risk - taking behavior and competitive strength, coupled with the collapse of predator populations, allowed them to more than double their population.

Not exact matches

That did not happen: there is no geological record of a world - wide flood, there is not enough diversity to regenerate the population we currently, there is not enough water to cover the earth to the height of Everest, the logistics of retrieving and returning animals to the then - unknown Americas, Australia, etc. were staggeringly difficult, managing the animals on the Ark was impossible — a few humans keeping predators from their prey, cleaning the waste, etc., pretty much all life on earth would have been killed, etc. etc..

Although insecticides are used to some extent, their use is mitigated through the introduction of predator insects to control the populations of insects that could damage fruit.

Biological pest control on organic farms, for example, relies on maintaining healthy populations of pest predators and parasitoids.

The Blanding's population has dwindled dramatically due to habitat destruction, an increased number of predators and an illegal pet trade.

«How fear alone can cause animal extinction: Even the smell of a predator can have disastrous effects in populations of small size.»

However, if, as we showed, the scent is sufficient to continue population decline, then even if the predators move on to other prey, and their scent disappears, this is unimportant for the survival of the population that is at risk whose numbers and reproductive ability have been critically affected by the passing smell of death.»

Disrupting a population could also produce ripple effects in other corners of the ecosystem, for example taking a food source from aquatic predators that feed on mosquito larvae.

Although considered one of the most successful predators on Earth due to the high kill - rate their cooperative hunting achieves, African wild dog populations are declining due to pressures including habitat loss and human - wildlife conflict.

Many of these animals are fierce predators that sit atop the food web, but Laidre's team found that they are also important subsistence resources: Arctic people hunt nearly 80 % of the studied populations for food and other uses.

It is also an apex and keystone predator, playing an important role in stabilizing ecosystems and regulating the populations of prey species.

The models included interactions and competition between predators as well as the influence of climate on vegetation and prey populations.

For the booming moose population of Isle Royale, a key species in the world's longest running predator - prey study on the island, skulls have shrunk by about 16 percent over a 40 - year period.

The researchers collected data on a wide variety of ecological variables that could affect gloomy scale populations, including habitat characteristics, the temperature at each tree site, and the abundance of predators and parasitoids.

But the pattern suggests that these natural population controls could be a defining feature of top predators, the authors argue online this month in Oikos.

Global loss of vagility alters a key ecological trait of animals that affects not only population persistence but also ecosystem processes such as predator - prey interactions, nutrient cycling, and disease transmission.

It is of no immediate concern to caiman populations in South America because the ants and caimans co-evolved there, and natural red fire ant predators, such as the decapitating fly, help keep the ants in check.

In parallel manner, the quantity of elk and moose are the limiting factor for the wolves: When the predator population runs low on food, in this case elk and moose, its population falls.

Gatenby calls this strategy an evolutionary double bind, and he explains it like this: imagine trying to control a population of rats by introducing predators, such as hawks, that can pick them off from the sky.

I mean, not every zebra of course have, [having] seen many lions eating zebras — but enough zebras do survive, so that their population continues on and that's pretty much the same down with human beings there, though of course in recent years it has gotten a little more challenging because we've become much more cunning and technologically empowered predators than we were before.

The researchers also found that moose mortality was higher at the edges of an expanding bear population than in the center of the bear population, leading them to conclude that moose with less exposure to predators were more likely to be killed.

Dr Martin Stevens from the Centre for Ecology and Conservation at the University of Exeter's Penryn Campus said: «As far as we know, this is the first time that research has demonstrated through the eyes of a predator how individual animals from the same population can tune their camouflage to match different backgrounds.

In ecological terms, these spiders are marine predators, and this explains how tiny, barren islands can support much denser populations of spiders than lushly vegetated inland areas.

Without natural predators, the rat population has swollen to many million, eating their way through tens of millions of ground - nesting birds» eggs and chicks in the process.

The consequences of such initiative were disastrous: Protected from hunting for 35 years, and devoid of natural predators, the beavers grew over 5,000 times their initial population, caused irreversible changes in the forest ecosystem, and started advancing over the continent.

And the researchers have reason to believe this change is in the works: The foxes have been outcompeted by growing populations of coyotes in the regions, which are becoming the top predators in areas where mountain lions and wolves have gone extinct.

Knowing that researchers in the early 20th century had shown that avian predators can wipe out an entire population of cicadas that emerges out of sequence, Koenig decided to take a look at how bird populations might affect the insects» cycles.

He found higher rates of nest predation in small woodlots near human communities because these areas had higher populations of raccoons (Procyon lotor) and squirrels (Sciurus spp.) and few, if any, large predators, such as cougars and bobcats (Lynx rufus).

The changes in biomass are worrying, says Michael Hirshfield, chief scientist of the advocacy group Oceana, based in Washington, D.C. Populations of small fish tend to boom and bust — making ecosystems less stable — much more when the ranks of top predators have been gutted.

The Architecture of a Trophic Cascade: Predator - Herbivore - Vegetation When HSS formulated their hypothesis, the scientific community commonly accepted that bottom - up processes, mostly related to competition between species, were the primary forces shaping populations.

The green world hypothesis provided an alternative view of population regulation driven by top predators, via carnivory.

The problem is that we don't know how much damage the predators do during winter, when the lemming population grows fastest, as, unsurprisingly, researchers do most of their field studies in the summer.

In two of them P. perezi has been co-existing with the red swamp crayfish for more than 30 years (populations of long - term coexistence), in another they have been sharing a habitat for 20 years (population of short - term coexistence), while the last two populations are found in an area which has not yet been colonised by the exotic predator (populations without coexistence),» adds the scientist.

Its problems have not gone away, and the population is now inbred, but a combination of measures including a captive breeding programme, habitat restoration and predator control are building up numbers.

More specifically, the spread of exotic predators is considered to be one of the major causes of population decline and species extinction on a global scale.

According to the scientist, the results reveal that the populations of these amphibians with a tradition of coexisting with the predator for 30 years (between 10 and 15 generations of frogs) present a pattern of activity that is totally different from the populations with less coexistence or no coexistence with the red swamp crayfish.

When both species are evolving, the traditional cycle may reverse, allowing predator populations to peak before those of the prey.

When the number of prey increases — perhaps as their food supply becomes more abundant — predator populations also grow.

For instance, if a mutation that confers viral resistance in a species of bacteria becomes dominant, that may change the predator - prey relationship by rendering the bacteria population safe from harm.

Rather than conduct experiments of voracious predators chasing and eating, or completely avoiding, prey, the scientists used evolving populations of digital organisms in a virtual world called Avida.

Populations of predators and their prey usually follow predictable cycles.

The experiments investigated both top - down (driven by predators) and bottom - up (food or resource limited) effects of the lights on the population density of a species of pea aphid, and in the presence and absence of predators including ladybirds.

It may be that in some areas, the most important drivers of tick abundance are the factors that control small mammal populations, including their food supply and predators, Kilpatrick said.

Unlike previous ones, the new model showed that predator and prey populations fluctuate less in complex food webs — those with long food chains, omnivorous predators, and competing species of plant - eaters.

«Studies that aim to predict the consequences of climate change on insect populations should consider additional factors that may ultimately limit growth and survival, such as the risk of being eaten by a predator,» Culler says.

«The more we know about the behavior of users and predator population, the more the analysis can be refined.

Birds play an important role in a wide variety of ecosystems as both predator and prey, in controlling insect populations, pollinating and seed dispersal for many plants, and in releasing nutrients on to land and sea in the form of guano.

In the late 1980s, the entire remaining population of the parrot was relocated on numerous occasions to various small islands that had to be re-vegetated and made free of feral cats and other predators.

Darwin Vest, who considered pesticides an irresponsible way to control spiders, examined the question of what predators might naturally control hobo populations.