Chasing Bats and Tracking Rats: Urban Ecology, Community Science, and How We Share Our Cities
Hypothesis Science is all about asking questions about the way the world works A hypothesis is a well thought out answer to a question we have asked but haven’t yet tested with an experiment or through observation To come up with hypotheses we often need to do research to get enough information to make a statement about what we think will happen Let’s say we want to know if plants grow larger when they have access to sunlight If we did some research we would find out that plants use the sun’s energy to produce their food through photosynthesis Based on this we could hypothesize that if a plant is given no light it won’t grow Experiment Once we have asked a question and come up with a hypothesis we can design an experiment to test it To find out if sunlight makes plants grow we could design an experiment with two plants on a windowsill We could cover one plant with a box so it gets no light and leave the other uncovered Since we are only interested in the effect of sunlight we would want to make sure that nothing else differs between our plants This means we’d have to use the same species of plant give them the same amount of water at the same time and keep them at the same temperature Observation While experiments are an important part of science most of the urban ecologists you’ll meet in this book are trying to make observations about nature in cities but many urban ecologists do experiments too Observation means watching the natural world to understand patterns and see what might change over time With observational science we don’t manipulate or change anything like we would with an experiment For example if we wanted to know the height of the average middle school student living in Fredericton New Brunswick in Canada we couldn’t answer this question by doing an experiment Instead we would need to go out and make some observations about Fredericton’s middle schoolers 4
Sampling When scientists try to make observations about patterns in the world we can’t always measure everything Instead we collect information from a smaller part of a population landscape or natural process that we want to measure This is called sampling It would be very hard and take a lot of time to measure the height of every single sixth grader in Fredericton so we might choose to measure the heights of children in classrooms from three different schools across the city This sample of sixth graders should give us an idea of the overall pattern of heights in all of Fredericton Data Data is all the information we collect and record while sampling or conducting an experiment With our plant experiment our data might be daily measurements of the height of each plant With our sixth graders it would be measurements of each kid’s height A dataset is a collection of all the data that comes from an experiment or project Bias Bias is a preference for one thing group or location over others Sometimes datasets can be biased toward or contain only information on certain groups of people or things because we aren’t careful with how we design our experiments or sampling When our experiments or observations are biased we can miss important pieces of information that will affect the answers to the questions we ask If we measured the heights of only sixth grade students in Fredericton our sample would be biased toward sixth graders We wouldn’t be able to use our data to say something about the heights of all middle school students in the city because we wouldn’t have height information for the seventh and eighth grade students also at the school To avoid bias we’d want to measure students from all grades from several middle schools in different neighborhoods so that our sample is representative of the whole population key terms 5
Processing A process is a series of related actions or steps that scientists take to get to an outcome In urban ecology processing refers to the steps we take to collect data when we are sampling individual animals plants or people in a population Many types of information can be collected during processing An ecologist might want to know how old an animal is how heavy it is and its sex male or female They might collect several different samples from an individual including fur blood or urine They might also want to tag the animal or plant so they can identify it later Processing the Fredericton sixth graders might involve taking their names so we know who we’ve measured measuring their heights and recording what school they were from Results Results are the end or outcome of an experiment or sampling In the plant experiment the result would be seeing which plant the one with light or the one without grew taller In the example with our sixth graders the result would be the average height calculated from the data we collected 6
Chapter 1 Chasing Down Big Browns How much do wildlife rely on city green spaces I bet the last time you played at the park you saw some wildlife sharing it with you Birds in trees Squirrels running around Turtles sunning themselves on rocks in a pond Parks and green spaces are often the closest thing to the natural habitats of animals and plants in urban environments So we like to think of them as being good habitat for wildlife in the city That’s what I thought when I set out to study city bats in High Park a large green space in Toronto Canada It seemed like the perfect habitat for city bats High Park is full of tall old trees that bats might like to sleep in It also has a large pond that bats could forage or hunt for insects But after chasing bats around the park all summer I’d barely caught any Where were the bats going at night to feed Where were they sleeping during the day It didn’t seem like bats were using the park at all But I was about to learn in the most dangerous way possible that this wasn’t quite the case Chasing Down Big Browns 7
