Welcome!

Hello my name is Mrs. Deacon. Please join me as I travel to Nova Scotia to study the ecology of mammal populations.

Wednesday, October 6, 2010

Working Together to Build a Field Station



     Part of our responsibilities when arriving in Nova Scotia was to assist the Primary Investigators in continuing to contruct a field station. Our daily schedule begins when we arrive at the site, Cook's Lake. The first things that we need to do is to check our traps from the night before. We then will do a variety of tasks - surveying for field signs, constructing GPS maps, or construction on the field station. I chose to assist in the building.

     The other teams this past year have constructed a lot of the station... our job was to put the finishing touches on the construction, as you can see in the video.

Tuesday, October 5, 2010

In Search of Deer using Scat

     Field signs are a useful tool to assist in counting populations and the presence of animals.  As stated in last night's post. field signs can include Scat / Poo (which scientists now can use DNA to determine the type of animal), tracks, burrows, feeding remains, damage to trees, calls / vocalizations, hair / other shed “bits” (ex: antlers from deer), dead animals – most you find as road traffic accident, and smell.
     In Nova Scotia, we learned a technique to examine an area for deep droppings.  This is called PGI or pellet group inventory.  We counted droppings in a 10x10 area which is 1/100th of a hectare.  On average, a white tailed deer will produce 20 piles / hectare / day (1 hectare – 100 meters by 100 meters).
     We found 51 droppings in our ten random sample areas.  To calculate an approximate number of white tailed deer in the area, 51 / 10 = 5.1 / 8 = 0.6375 white tailed deer / hectare.  So if we take the area of the whole place of interest, say 54,000 and multiply it by 0.6375, it gives us a rough population of approximately 34,000 deer in the area.

Monday, October 4, 2010

Analysis of Data Collected

      In order to collect usable data, we can use many different techniques in the field.  We can begin with observation of the organisms in the study.  Depending on the organism, it may be difficult to observe much of the population.  If observation is letting you down, you can look also look at field signs.  Field signs include Scat / Poo (which scientists now can use DNA to determine the type of animal), tracks, burrows, feeding remains, damage to trees, calls / vocalizations, hair / other shed “bits” (ex: antlers from deer), dead animals – most you find as road traffic accident, and smell.

Deer prints

Beaver Dam

Beaver damage



Porcupine Scat

     Finally, we can set up traps.  We here in Cook's Lake, have set up two types of traps: live traps and camera traps.  The first type, live traps can allow us to measure the animal, assess its health, take samples from the animal, find the sex of the animal, and mark as an individual. A camera trap does not inconvenience the animal at all and does not stress the animal.  We may be able to see the animals behaviorand numbers, and camera traps are not  as much labor as live traps, but they are very difficult to recognize individual animals.
     The purpose of these methods is to estimate an organisms population within an area.  With the live traps, we have been using the "Mark - recapture method" to estimate the size of the wildlife population.  The formula we use to extrpolate the population is called the "Lincoln - Peterson Model", which is as follows:

[(N+R)/R] x M=Population estimate


where: N = new captures, R = recaptures, and M = marked.
 
So therefore, using this formula, we are able to figure...

Capture site #1: Hardwood Brush

Chipmunk [(0+1)/1] x 4=4
Deer Mice [(1+2)/2] x 4 = 6

Total [(1+3)/3] x 8 = 10.6 / half hectare or 25 / hectare

Capture Site #2 : Forest

Chipmunk [(1+1)/1] x 1 = 2
Deer Mouse [3+1)/1] x 4 = 16
Red Backed Vole [(2+3)/3] x 5 = 8.3
Bog Lemming [(1+0)/0] x 1 = 2

Total [(7+5)/5] x 11 = 26.4 / half hectare or 53 / hectare

What does this data tell us?  Define the term density. What is the density of each of the populations sampled? What are four factors that may impact the density of a population? 

Sunday, October 3, 2010

Kejimkujik National Park

     Today, we travelled to Kejimkujik National Park ("Keji") to examine the forest.  Keji "is representative of the Atlantic Uplands forest region, including mixed coniferous and deciduous vegetation. While much of the forest has been disturbed by past logging, superb stands of large old growth hemlock and sugar maple-yellow birch can still be found." (http://www.pc.gc.ca/) Much of Nova Scotia's forests have been damaged due to many years of logging.  Within Keji, we went to an area called the "old growth forest" containing Hemlock that gave us insite into what the inland area of Nova Scotia would have looked like if the trees had remained.
     Eastern hemlock is one of the most shade tolerant tree species in the Park. Where it can escape severe fires, it can become the oldest species as well. These factors allow it to gain dominance in size and composition on the absence of major disturbance. Several groves of hemlocks, from 200 to 300 years of age, are found in the Park. 

    Forest fires do not often occur in this area, therefore the Hemlock forest has been able to reach status as a climax community. What is a climax communty?  What happens in a forest after a forest fire?