Eco Blog
Thursday, April 25, 2013
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.
Thursday, April 18, 2013
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.
Thursday, April 11, 2013
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!!
Friday, April 5, 2013
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.
Friday, March 29, 2013
Lesson 8 - REDD Case Study
This lesson shows us how to project
deforestation rates based on socioeconomic variables. An econometric model
specifies the statistical relationship between economic variables pertaining to
a particular economic phenomena, in this case deforestation. It is useful to
use an econometric model to simulate deforestation because it takes into
consideration the many complex dynamic phenomena that produce deforestation as
a result. These types of simulation models are important for evaluation of the
potential for future deforestation under a business-as-usual scenario. In the
case of this example, this is important in order for countries to receive
incentives from reducing their carbon emissions from deforestation. REDD stands
for “reducing emissions from deforestation and forest degradation” and is an
idea that developing countries who do this over time, can receive financial
compensation for doing so. This would require a country’s emission levels to be
lower than historical levels and would require them to know historical emission
levels and whether they were high or not. A model like this is important to
predict future deforestation rates based on multiple economic variables to see
if receiving compensation for REDD is a possibility for certain countries.
The
model used for this lesson contains a spatial lag regression that is applied to
compute the influence of five variables on deforestation: Percentage of crop
areas, cattle herd density, percent of protected areas, proximity to paved
roads, and migration rates. The five variables listed are the five static
variables that are used to determine the probability of deforestation. The spatial
lag regression makes it so that the deforestation does not happen right off in
respect to the spatial variables and instead occurs over time and spreads over
time. This models “spatial neighborhood matrix” allows neighboring cells, in
this case municipalities, to have an influence on the cell in question. This
means that each cell is not independent of the surrounding cells and the
variables in the surrounding cells will effect it. In terms of deforestation,
this means that if one cell becomes deforested, then it is likely that
neighboring cells will become deforested as well over time. Because of this, we
would expect to see deforestation occur in expanding clumps instead of in
random patches.
After
running the model with various cattle herd and crop rates, it was determined
that the smaller the rates the better because this will produce a lower, steady
rate of deforestation and CO2 emissions. A high rate of cattle herd and crops
means a rapid increase of land use and therefore a rapid increase in
deforestation and CO2 emissions and an overall unstable state.
The
model is simulated for 20 years and a map output is produced for each year.
Below are three output maps from the model starting with the first year, the 10th,
and the last year:
At first, it looks like these images are all the same and
there is no difference. But looking at the amount of yellow in the first image
compared to the last one, you can see that the yellow areas are more filled in
and have less green areas between them. This shows that the areas surrounded by
deforestation (yellow) eventually become deforested as well and that
deforestation is similar to the spreading of a disease. The most worrying part
about this is that in the first year, there were very small areas of
deforestation in the middle of green (forested) patches. Those were very small
and may not have caused many problems in the first year, but because of the
spreading of deforestation, these areas have become much larger by the last
year. At this point they will cause problems such as habitat fragmentation for
wildlife species. It also seems that the deforestation has spread faster
between 2010 and 2020 as opposed to 2001 and 2010. This is worrisome because it
means that the rate of deforestation is increasing as time goes on. I could not
get any data to show up for cattle herds, but below is a graph for annual deforestation
and a graph for crops for years 2001, 2010, and 2020:
As you can see, the crop rates are similar every year, but
steadily increase every year. The seasonal changes are always the same, but the
overall annual rate for crops increases. For deforestation, however, the
seasonal changes are not always the same. 2001 and 2010 are similar in that
their peak deforestation rates were at the same time, but in the year 2020, the
peaks were at the times where deforestation was lowest in the past. Overall,
deforestation rates for 2020 do not seem to be higher than they were in
previous years. In 2001 and 2010, deforestation rates seem to be the opposite
of crop rates but in 2020, deforestation rates become a bit more similar to the
seasonal changes of the crop rate.
In the scenario parameters group, I changed the cattle herd
expansion and crop expansion values from 0.05 to 0.5. This simulates a rapid
increase in land use. Below are the output maps for years 2001, 2010, and 2020
again:
As you can see in these
output maps, the spread of deforestation occurs at a much higher rate and by
2020, a larger amount of forested areas have become deforested because of the
demand for crops and cattle herds. It is impossible to see these images as
something that is not a problem. The amount of forested land left after just 20
years is alarming. Below are the graphs for the annual crops and deforestation
rates:
As you can see, for the crop rates, they started out low in
2001, increased a large amount by 2010, and then dropped down to 0 by 2020.
With deforestation, the highest rates were in 2001 and they continually dropped
in 2010 and even more in 2020. Maybe the rates for both the crops and
deforestation decrease by 2020 because there is drastically less land to use
for crops and deforestation because most of it has already been converted.
Next is estimating the carbon losses from the two scenarios
presented above. This will be done with the carbon bookkeeping model which is a
very common approach to estimating carbon emissions. This model calculates
annual carbon emissions by determining annual deforestation (from our previous
model) and overlaying these deforested areas on a map of forest carbon biomass.
This model assumes that carbon content is 50% of wood biomass and 85% of carbon
stored in trees is released into the atmosphere during deforestation. This
model was run for both scenario 1 and scenario 2. The graphs for the annual
carbon emissions in tons for each scenario, CO2 emissions, and the graphs for annual
deforestation in hectares for each scenario are below:
As you can see, these graphs all look the same. With the
small (0.05) cattle herd and crop rates, the annual rates of deforestation and
carbon emissions were fairly steady without much fluctuation. With the rates
much higher (0.5), the rates of deforestation and carbon emissions instantly
were higher and fluctuated much more. Overall, the second scenario emitted much
more CO2 into the atmosphere and much more deforestation took place. Therefore,
it is best if the cattle herd and crop rates remained relatively low so the CO2
emissions and deforestation rates would remain low and steady.
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