Friday, April 23, 2010
This was our last day together in Nova Scotia, tomorrow we'll all get on a plane and go back to our homes. So that got me thinking about what makes a good home. We've been learning about the different habitats of animals we see here and that some of them are extremely vulnerable when their environment changes. People often make the mistake of thinking that other animals can make do wherever they are, the way that people can. Humans have managed to be successful at living in almost every corner of the planet. We can make clothes, build shelters, and trade with each other for what we need. Sometimes we even get so clever that we forget how much we still depend on our environment for survival. I don't grow or gather my food, or go to the river for water, or make my clothes, or build my home, but I could. I would spend all of my time doing it, but I could do it. Instead, I can rely on other people to help me get these things from the earth so I can spend my time working, playing, or thinking. On the other hand, most animals are spending all of their time trying to meet their basic needs of food and shelter. Mammals sometimes live alone or in groups, but they are very territorial. They may need a small or a large territory to survive in the wild, which they will defend. We as humans can understand the need to protect our home, but again we have to remember that people are not like other animals. Animals defend their territory because there is only enough food and room to raise babies for a certain number of animals. Only the strongest animals, which have found enough food to be healthy, will be able to defend their home. Being able to keep a territory means that animal or group of animals can secure food and shelter. This really sunk in for me this week when we captured a meadow vole. It was a female that had a long black strip of fur on her back. Fur can grow back black from an injury, and from the look of it, she was probably attacked by a bird of prey but then managed to escape. We caught her again in the same trap a few hours later, but when we opened the trap she was dead. Although we were sad, it was probably just her time. She had made it through the winter and had survived an attack, which is more than most voles can say. But Christina also suggested that maybe when she was attacked by the bird, she had been carried a bit and landed outside of her territory. She would have survived for the moment but then would have no home or stockpile of food. If it was a good place for a vole to live, other voles would be living there and keep her out. So she would have been in a tough situation. When we put our trap out we could have been saving her life! The trap is warm, nothing else lives in it, and it's full of food - perfect if you don't have your own home or food. Maybe that's why she was so eager to go back in once we released her. This is another reason why you never release an animal into a place it is not familiar with. Other animals are as connected to their homes as we are! And I am happy to be going back to mine :)
Thursday, April 22, 2010
I celebrated the Earth today by cutting down some trees! I prefer to say, though, that I spent today creating more grassland habitat. It is really important to remember that different animals may have very different kinds of habitat. If there was only forest at Cook's Lake, there would be many fewer species able to live there. Chris and Christina are trying to keep the 350 acres of land they manage as diverse as possible, providing homes for species that are losing habitat everywhere else. Forests are wonderful too, and planting trees in other places might be the right thing to do. People can take forest for granted here since there seems to be so much of it, but it turns out that not all forest is the same. Certain trees are suited to certain conditions. Tamarack is a native tree here and likes boggy wet land, and Red Oak grows in dry soil, so unless you knew the land pretty well you could plant a tree where it wouldn't survive. Even though it is true that much of Nova Scotia is forest, not as much of it is healthy and strong. If we take from the land, we have to be thoughtful about the ways that we try to give back. That means really observing the environment that you are in; the weather, the animals and the people that use it, and what it looked like in the past. What may be best in the long term may not be the easiest solution at the moment, like cutting a few pine trees down.
Last night we headed to a nearby lake to observe a family of beavers at their lodge. I'm borrowing pictures taken by Sue who has a great camera, since it was dusk and hard for me to get a good shot. Christina told us before we went out that beavers are sensitive to movement and will warn other beavers of potential danger by slapping their large tail on the water and diving underwater. This tells predators that the beaver has seen them and not to bother trying to hunt it. So, we all lined up along the water's edge and sat perfectly still and quiet to see what would happen. At first I saw a red-winged blackbird sitting on the lodge. Then out of the corner of my eye I saw something in the water. Since beavers swim with their feet, not their tail, it left a V shaped trail of water behind it. There was also a muskrat that came around, which is smaller, but they swim mostly with their tails and leave a kind of zig-zag trail of water behind them. The beavers would swim back and forth to a little island of sticks that they had piled up. We could even hear them gnawing on the bark! Sometimes they would bite of a branch to carry over to the lodge. Through my binoculars I got a really good look at them!
Tuesday, April 20, 2010
Last night we sat down with Chris to have a look at the data we have collected so far. They set out with a question they wanted to answer, developed a method that would give them reliable results, and we are helping them collect data. Answering their question can only happen after data has been collected over a long period of time. Once you collect enough data, the problem is to find out what it tells you. The data doesn't mean anything until you have examined it. He explained their methodology for doing this. One way is called Capture-Mark-Recapture or CMR. This means they count the number of recaptured animals after a few days to estimate how many animals are in an area. There was a very useful math formula we could plug our data into and come up with an estimate: based on the fact that we caught 7 voles, and recaptured 5 of them over 5 days, we can estimate that there are 13 voles in 1 hectare (100m x 100m square) at last week's location. Very cool! Here is Anne checking the new traps we set yesterday. There is some grassland, some forest, and also some hard brush. Malakai, here's what the red fox scat looks like! They are rare around here because they compete with coyote for the same food, and the coyote is much bigger. They also leave scat as a way of marking their territory. They leave it on top of prominent places like big rocks. Can you see all the fur and bones twisted up in it? We only caught one mammal so far at Cooks Lake, it's a meadow vole, as opposed to the red-backed voles we caught last week. Do you see any differences? We saw a rotted tree stump on a walk today, but the core of the tree had decomposed before the branches, so you can see how the branches leave their mark inside of the tree as it grows.
Monday, April 19, 2010
We started setting new traps in a new location today. Christina's family bought some property near Cook's Lake and they have been maintaining it for almost 20 years as a nature preserve. There is a lot of work involved in helping the land stay healthy for many types of plants and animals, as well as keeping it safe and easy for volunteers to walk around in the forest. Parts of this land get very wet in the spring and create large puddles that will dry up by the summertime. But while they exist, they are extremely important habitat for amphibians, such as frogs. They lay their eggs in the pond and if they time it right, it will be a pond long enough for the eggs to hatch and for the tadpoles to grow enough to leave the water. One project volunteers can help with is building pathways over the ponds so people don't step on these eggs! There's also a beaver at the lake. Beavers are very territorial and there will usually be only one pair of beavers and their kits on the lake. Most beavers here don't build dams because the lakes are already deep enough to build their lodges. We saw some evidence of someone's handiwork! Remember our weevil study? Weevils are a problem here for conifers, not deciduous trees. They lay their eggs in the bark. Well, it's only a problem if you are a forester trying to grow straight trees. It causes a new trunk to grow out of the spot where the old truk was damaged by the weevil, so the tree can look quite bushy after some time. It's great if you're a bear or a porcupine looking for a place to nap. Here's an example of an old white pine with weevils:
Sunday, April 18, 2010
Kejimkujik in the Mi'kmaq language means "land of the spirits." There are old growth hemlocks here, one of which they have dated to 500 years old. Look closely at this tree, can you think of how this happened? It rained a bit for the first time today, but it was still beautiful: Of course, we also looked for more scat. Here is a nice shiny pile from a deer!
So how does keeping trap of mice and voles, counting snowshoe hare scat, and mapping damaged tree bark help us understand climate change? Well, that is an interesting question with an interesting answer. Chris spent some time explaining his professional work and the science behind climate change. He did his best to put some very complicated data into terms that we could understand, since we haven't studied it before. First of all, it is important to call it climate change rather than global warming, since temperatures on the earth have always been changing throughout history. Actually, the average temperature at the moment is even a bit cooler than it has been in the past. What is alarming is the rate of change. Animals can be very good at adapting to their environment but they can't do it very quickly. When temperatures change faster than they can adapt, many of them will die off, especially the ones that have specific requirements for food and shelter. Let's take the snowshoe hare for example. It is an important source of food for birds of prey and large mammals such as coyote. Incredibly, when the days get short in the winter time, signals in their brain start to turn their fur from brown to white. This makes sense, since usually there will be snow in the winter and white fur will help it camouflage. But, if there is no snow and the hare turns white, it will be very easy for predators to see it. On the other hand, if it snows in the spring when the longer days trigger the fur to turn brown, the hare will be brown on a background of white and again very easy for predators to see. Winter weather here can change a lot anyways, and with increasing unpredictability due to rapid climate change, Chris and Christina are interested to see if this will eventually hurt their population. This is just one example, can you think of others? I should also explain what "rapid" means in terms of earth's history. Scientists have a way of measuring temperatures on earth even millions of years ago. Over a 20,000 year period of time, there was a 6ºC change. This caused a mass extinction of plants and animals. Humans have made a big impact in the last 200 years. Don't you think this must have some lasting effects?