Moose first came to Isle Royale in the early 20th century, and for fifty years, their numbers fluctuated with weather conditions and food abundance. The wolf population suffered from really high rates of inbreeding, so the build up of genetic abnormalities meant that they wolves were much less fertile than genetically normal wolves. Overall, predation rate is pretty variable from year-to-year. Under all ideal situations, the complex nature of Isle Royale should be reverted back to a normal bottom-up or top-down relationship, but because of other factors such as resource strain, climate change, disease, and ticks, the wolf and moose population do not strictly follow these models. R2 is a statistic that can range from zero to one. Small, isolated populations exhibit high rates of inbreeding, which means to mate with close relatives. The most remarkable observation is just how variable kill rate is.
For a more technical treatment of these ideas, see Vucetich et al. On one hand, predators could focus on prey that would have died anyways - prey that are sick or old. The simplest answer is, it depends. So, how has inbreeding and the subsequent genetic rescue affected population dynamics on Isle Royale? Often I put on a white coat and stethoscope to play it up. Low wolf abundance provided an unprecedented opportunity — a natural experiment of sorts — to see how moose would respond to reduced wolf predation. Stable populations are also said to exhibit density dependent fluctuations.
A value of zero would indicate that moose per wolf explains none of that fluctuation. Even though each wolf nearly doubles his consumption per month, that still does not compare to a population of moose that is five times as high. In 2009, with the help of Jannike Räikkönen, an expert in Canid anatomy from the Swedish National Museum, we systematically inspected the skeletal remains from 50, or so, Isle Royale wolves that had been collected over the past five decades. The accuracy of our predictions for Isle Royale wolf and moose populations is comparable to those for long-term weather and financial markets. Age structure is important for a second reason. These insights and discoveries are all presented here for you.
Afterward, ecologists naturally draw conclusions about the nature of our environment. Wolves represent a pressure from above. More specifically, the vertical axis reflects the percentage by which the wolf population grew each year. Or, for example, environmental stochasticity might, also for example, be manifest as an outbreak of disease, causing an unexpected population decline. For example, in 1977 the wolf population grew from 34 to 40 wolves, an 18% increase or 0. The wolf population, with 30 individuals living in three packs, had been thriving until 2006. They all conspired against the moose population which collapsed in 1996.
The hope had been that knowledge about wolves would replace hateful myths and form the basis for a wiser relationship with wolves. Canine parvovirus, a disease inadvertently introduced by humans, was largely to blame for the decline. The project began during the darkest hours for wolves in North America—humans had driven wolves to extinction in large portions of their former range. The winter had been more severe than any in over a century. Within about five years of his arrival, the inbreeding coefficient for Isle Royale wolves dropped well below 0.
When we consider this extreme observation, then the most parsimonious relationship between moose abundance and population growth rate is a complicated curve 3rd order polynomial. The per capita kill rate or sometimes just called kill rate is a special statistic indicating how much food the average wolf in a population gets. Then students are presented with reference information about the prenatal effects of alcohol, tobacco, and illegal drugs and asked to summarize the effects and make conclusions. Each cup has about 50-100mL of water in it depending on size of cup. Inbreeding depression and genetic rescue in the wolf population.
I was very pleased with the program, and want to use it again, and try at least one more of the simualtions next semester. Isle Royale is a remote wilderness island, isolated by the frigid waters of Lake Superior, and home to populations of wolves and moose. We consider the most likely explanation in the next section. You need to make quadrats to serve as sampling units. Together, the numerical and functional responses aim to explain the causes and consequences of fluctuation in per capita kill rate. The problem is that once you have gotten your nifty new product, the isle royale population study lab answers gets a brief glance, maybe a once over, but it often tends to get discarded or lost with the original packaging.
The students take turns acting as predators of butterflies camouflaged on various patterned cloth backgrounds. Wolf and moose densities are the total number of wolves and moose on Isle Royale, divided by the size of Isle Royale, 544km 2. That is, wolves have an important destabilizing impact on moose population dynamics. By 1980, the study in its 22nd year, the moose population had tripled from its original size and then declined to half its maximum size. In retrospect, these changes were likely the result, at least in part, of inbreeding depression.