What is the keystone herbivore hypothesis?
This fails. to explain the simultaneous extinctions of a number of mammalian and avian species not obviously vulnerable to human overkill. I propose a “keystone herbivore” hypothesis, based on the ecology of extant African species of megaherbivore, (i.e., animals exceeding 1,000 kg in body mass).
Why are megaherbivores important?
Through their apparent disregard for the landscape of fear, megaherbivores play an important role in lateral nutrient transport by distributing nutrients across the risk gradient.
What is a Mega herbivore?
(ˈmɛɡəˌhɜːbɪvɔː ) noun. a large herbivore, such as an elephant, weighing more than 1000kg.
Are elephants megafauna?
Among living animals, the term megafauna is most commonly used for the largest extant terrestrial mammals, which includes (but is not limited to) elephants, giraffes, zebras, hippopotamuses, rhinoceroses, and large bovines.
Do keystone species have high biomass?
Certain species, termed keystone species, have a disproportionate influence (relative to their biomass) on ecosystem functioning. The loss of a keystone species will produce a cascade of effects on the diversity and function of the remainder of the ecosystem (Menge et al., 1994).
What makes an organism a keystone species?
A keystone species is an organism that helps define an entire ecosystem. Without its keystone species, the ecosystem would be dramatically different or cease to exist altogether. Keystone species have low functional redundancy.
How does ecosystem rehabilitation work?
Ways to restore them include reducing tillage, using more natural fertilizer and pest control, and growing more diverse crops, including trees. These steps can rebuild carbon stores in soils, making them more fertile so countries can feed their growing populations without using even more land.
What is ecological replacement?
Ecological replacement as a conservation tool presupposes that nonnative taxa can restore degraded ecosystems by performing the ecological functions of extinct taxa. This assumption is rarely tested however, largely because it is difficult to quantify the functions of species extirpated long ago.
Do any megafauna still exist?
Of all the mega amphibians, only one species remains on Earth. Weighing in at 40 kilograms and stretching up to 1.8 metres, the Chinese Giant Salamander (Andrias davidianus) is sometimes called a living fossil, one of the few survivors in a family that dates back 170 million years.
Do humans count as megafauna?
Megafauna are big animals. Elephants are megafauna, as are giraffes, whales, cows, deer, tigers, and even humans. Megafauna can be found on every continent and in every country. For each living species of megafauna, there are a large number of extinct megafauna.
What would happen if a keystone species was removed?
Keystone species have low functional redundancy. This means that if the species were to disappear from the ecosystem, no other species would be able to fill its ecological niche. The ecosystem would be forced to radically change, allowing new and possibly invasive species to populate the habitat.
How do you conduct a hypothesis test on the population mean?
Again, to conduct the hypothesis test for the population mean μ, we use the t -statistic t ∗ = x ¯ − μ s / n which follows a t -distribution with n – 1 degrees of freedom.
How do ceratopsids adapt to high-fibre herbivory?
The shearing tooth batteries of ceratopsids are much better adapted to high-fibre herbivory, attested by their scratch-dominated microwear signature. There is tentative microwear evidence to suggest differences in the feeding habits of centrosaurines and chasmosaurines, but statistical support is not significant.
Will Minitab conduct hypothesis tests in this course?
The good news is that, whenever possible, we will take advantage of the test statistics and P -values reported in statistical software, such as Minitab, to conduct our hypothesis tests in this course.
How do you state a hypothesis in a research paper?
State your research hypothesis as a null (H o) and alternate (H a) hypothesis. Collect data in a way designed to test the hypothesis. Perform an appropriate statistical test. Decide whether the null hypothesis is supported or refuted.