Looking into the future

I have spent the past three or so blogs focusing on my project and having written a rough draft of my paper for today, the last thing I want to do is write more about it. Therefore, I am choosing to write about a more positive subject - my future. Beginning May 7th, I will be a crew leader leading a crew of students based out of Lake Umbagog National Wildlife Refuge in New Hampshire. My crew and I will be doing bird and vegetation surveys in spruce-fir forests to see how birds respond to different forest management techniques. Since this job is outside in the woods everyday all day, you can probably guess that this job has a lot of connections to ecology. Everything about this job, actually, is ecology. I'm mostly excited for the data gathering part of this job because I get to walk around the woods and keep track of all the birds I hear and see so I get to test my bird identification skills which I love. It will be interesting to see the different types of birds present in these types of forests because I haven't spent much time in spruce-fir forests. I'm curious to see how these interior forest birds are different from birds that live on the edge of forests and in more urban areas. But the results from the research we are doing will also be very interesting. I am curious to see the birds responses to different forest management techniques and if that has any effect on how people decide to manage the forests. It is safe to say that ecology will be on my mind every day of my three months on this job, especially because I'll essentially be living within the spruce-fir forest ecosystem being in a remote area without cell service or internet! I think this class is what has put these things in my mind and has given me a better understanding of the natural world around me.

Beginning of introduction - deer info

Many people firmly believe that hunting is an essential management technique for the white-tailed deer population in the Americas. There are many subspecies of White-tailed deer, mostly geographically distinguished, but the overall species currently inhabits almost all of North America and Central America and parts of South America and Canada. They range from as far north as Prince George and British Columbia in Canada and as far south as Peru in South America. Their total population size is estimated to be 25 million. White-tailed deer are able to survive in a variety of habitats from large woods of the north to deep saw grass and swamps in the south. They also inhabit farmlands, cactus and thornbrush desert areas. The ideal habitat for white-tailed deer is in dense forest for cover, but near edges for food. Deer are herbivores, but feed on a variety of plants including buds and twigs of many tree species, cacti in the south, and other tough shrubs that other mammals would avoid. Their ability to survive and adapt in a wide variety of habitats and their ability to forage on a wide range of plants makes it easy for this species to thrive. The constant development caused by humans increases the amount of edge present in the landscape which destroys habitat for many other mammal species, but it has little effect on the deer populations which makes it easier for white-tailed deer to outcompete other mammal species that need large forests.

White-tailed deer are native to North America, but their populations have not always been as large as they are today. They have an immense influence on the landscape as they change the composition of plant communities through their foraging and can often lead to over-browsing where their population is large.  This can cause serious damage to the vegetation of forests and can also be destructive for crops, vegetable gardens, and ornamental plants when there are white-tailed deer living in close proximity to humans. Deer are also a large cause of car accidents and can cause serious injury to the occupants of vehicles. They also serve as important vectors for disease such as Lyme disease because they serve as hosts to the ticks which carry the disease. These are all very real problems that having a large white-tailed deer cause.

In Vermont, deer are found in mountainous areas, river valleys, agricultural lands, forests, and even in backyard suburbs. In their northern range, deer yards are a critically important habitat in order for them to be able to survive the winter. Only 7-8% of Vermont’s forests make up this critical habitat type and is possibly a limiting factor for their population growth. They may move 10 to 15 miles to reach a deer yard. Wintering deer yards must contain evergreen trees to catch the snow in their branches and keep the snow from getting too deep. The trees also provide a thermal cover to protect the deer from wind and below freezing temperatures. Deer hunting in Vermont is currently legal and thousands of people partake in the activity. Some hunters hunt for sport, while many others believe that it is an important way to control deer numbers which is important because an over-abundance of deer causes many problems. Hunting is a way to balance the needs of the deer and the needs of the people and is an important element in the cultural heritage of Vermont. The regulated deer hunting seasons in the fall of each year is how deer numbers are currently managed.

Project Project Project

Well, my project is still confusing to say the least. I think I've realized that figuring out the model set up is the part that is confusing me the most and that once I figure that out, I’ll know more about what to do with the data I need. I think my model is similar to lesson 5, the multiple criteria evaluation because I will need to have a calc categorical map for each environmental factor (land cover, slope/elevation, wintering areas, etc.) with an equation that will produce a categorical map with rankings (0-5 maybe?) for each cell on the map. Then all the output maps from those calc categorical maps should be combined to create an overall habitat suitability map where each cell is ranked (again 0-5) for habitat suitability for white-tailed deer. This habitat suitability map will determine where the deer population will spread as time goes on. Eventually the current population growth rate will have to go into the model to determine what the population will look like with continued hunting but I will also have to use some sort of equation to determine what the population would look like if there was no hunting. I know the biggest limitation after hunting is winter severity so if I find out how much that is effecting the population then I can use that to help with figuring out what the population growth rate would be without hunting. Not quite sure how to figure that out though. I think I need to set up another time to talk about it with prof. Galford!! 

White-tailed deer project blog #2

My project is slowly beginning to come along. I was able to get a GIS layer of the town boundaries in Vermont that contains the harvest rates for each town for 2010, 2011, and 2012. I also have a WMU (wildlife management unit) boundary layer for the state of Vermont. This layer contains a column showing the number of hours hunters logged during the annual deer hunter survey to act as a proxy for overall hunter distribution/effort. Along with the GIS layers, I have the current deer population estimate (pre-hunt) by physiographic region and WMU and the sighting rates for each region/WMU and statewide from 2003-2012. Luckily, there is a very cooperative deer project leader working for Vermont Fish and Wildlife who is more than willing to give me any deer information I need for my project. From the information given to me, I have the hunting kill rates per WMU which comes from the success rates and the number of permits distributed. To explain the differences in kill rates and success rates between the WMUs is likely based on multiple environmental characteristics. These would be the same environmental factors that are influencing the differing deer populations in each WMU or town. These environmental factors include land cover (forest or not), proximity to edge, slope/elevation, proximity to deer wintering areas, and possibly distance to roads and rivers. I think this would make my model a type of multiple criteria evaluation. To account for these factors, I think I would need multiple calculate map functors with equations for each of these factors to determine the habitat suitability of each cell of an input landscape map of Vermont. Maybe I could get the output to be a categorical map with values from 0 to 5 ranking the habitat suitability of each cell based on the equations.

As for the deer population simulation without hunting, the biggest non-hunting factor impacting deer mortality is winter severity. This needs to be taken into consideration when trying to determine how the population will grow and spread without hunting pressure. In this case, it may be important to consider historical WSI recordings and the region specific regression equation that the deer project leader can provide. This is all the information I have so far on my project. It’s not much, but it’s definitely a start and it is slowly becoming less confusing and daunting.