By Corey Alderson, Biologist
Kansas Department of Wildlife, Parks and Tourism
Kansas has on record approximately 470 species of birds, 88 mammals, 55 reptiles, 30 amphibians, and 140 fishes. A few of the species included on this list are considered extirpated from the state and no longer occur here. Other species included on the lists are non-native. Some species do not call Kansas home year-round and may only spend brief time periods in the state.
With the diversity of wildlife we have in Kansas, we also need to have a very basic understanding of how wildlife tries to sustain their populations. Some species mature rapidly and have an early age of first reproduction. They have a relatively short lifespan, but have a large number of offspring at a time. In return, they have few reproductive events, have a high mortality rate, and low offspring survival rate. These species also have minimal parental care and investment in raising their offspring. Other species of wildlife mature more slowly and have a later age of first reproduction. These animals have a longer lifespan, have fewer offspring at a time, but have more reproductive events spread out over a longer span of time. They also have a high parental investment in raising their young and therefore have a higher offspring survival rate. Species use different strategies to sustain their populations and invest energy in different ways to complete their life cycles. Their main objective is to use the available resources to survive on the landscape and produce offspring for the next generation.
We all realize that wildlife populations can and do fluctuate from year to year. This occurs for various reasons and is to be expected. One thing we must understand is that the landscape is constantly changing from year to year to some degree. These changes can be as simple as crop rotations or whether or not a pasture is burned in a given year. Because of this, the amount of available resources wildlife need will vary from year to year also. The term “resource” means not only food, but the cover they use.
Nature plays a role in how successful populations are from year to year. Events such as rainstorms, hailstorms, ice storms, periods of drought, and seasonal changes such as mild winters affect populations. As described earlier, a species’ ability to respond to these events vary. The number of individuals in the breeding population, the strategies to produce offspring, and the survival rate of those offspring dictate how the population responds. Favorable resources in the form of cover and food will allow populations to be more successful in rebounding from severe weather events.
We generally do not get too concerned about the annual population fluctuations. We understand them and realize that populations can rebound from a bad year. We do get concerned about those species that are showing long-term declines in their populations. These populations are lacking adequate resources needed to sustain their populations. Understanding that what we do on the landscape has a direct effect on wildlife populations will be important in the years to come. It is not by chance that some populations are doing well and others are not.
To learn more about natural resources conservation, please contact your local Natural Resources Conservation Service office or conservation district office located at your local county USDA Service Center (listed in the telephone book under United States Government or on the internet at offices.usda.gov). More information is also available on the Kansas Web site at www.ks.nrcs.usda.gov. Follow us on Twitter @NRCS_Kansas. USDA is an equal opportunity provider and employer.