Succession + Change in Ecosystems and Environmental Monitoring

Change is always occurring in an ecosystem For example: a landslide wiping out an entire ecosystem Or a seed carried by the wind to a vacant lot where it grows, reproduces and flourishes and may even replace plants that were already growing

Succession The gradual process by which some species replace other species in an ecosystem is called succession. Primary succession is the gradual growth of organisms in an area that was previously bare, such as rock Example: lichens, mosses and ferns will first appear on a bare rock

The gradual growth of organisms in an area that previously had a number of organisms is known as secondary succession Example: the regeneration of a burned forest area is an example of secondary succession - wildflowers and other plants that grow best in sunlight will spring up first – blueberry bushes love growing in burnt soil!

Human Activity Humans affect the environments around them in many different ways – good and bad! Ways we’ve affected our environment – spread of urban areas, highways, parking lots, forestry, use of pesticides Any others????

Some species can adapt better than others to changes in the environment Example: What animals have you seen in a big city? Raccoons at UBC (Vancouver) Fox in Toronto Black bear in my parents back yard ????

Biological Control Rather than use pesticides, you can control pests using their natural enemies. This method, called biological control, can be an effective and limits or eliminates the need for pesticides. Example: Leafy spurge is a weed that was accidentally brought to Alberta in late 1800s. It grows faster than pasture grasses. In 1983, the black dot spurge beetle was introduced and has done a very good job of controlling the growth of leafy spurge.

Introduced Species Purposely introducing a new species (like the black dot spurge beetle) is now only done after very extensive research. WHY??? Many species are accidentally introduced to an environment where they are not naturally found. These are called introduced species. Example: Zebra mussels in Great Lakes, Scotch Broom in BC, Purple loosestrife in BC, AB

Species in Danger Many species in Alberta and across Canada are in danger of extinction If an animal becomes extinct, it no longer exists anywhere in the world Causes of extinction are: habitat loss, species introduction, over-hunting, over-fishing, pollution, climate change

Canadian Extinctions Great Auk Sea mink Dawson’s caribou Blue walleye

Endangered Canadians Eastern cougar Bowhead whale Right whale Burrowing owl Grizzly bear Sea otter Whooping crane Piping plover

Environmental Monitoring Ecosystem monitoring (environmental monitoring) is a way to check the condition of an ecosystem by comparing the results of investigations done at different times

When is monitoring done? Sometimes scientists monitor after a disturbance has occurred – earthquake, eruption and plant succession. Sometimes scientists monitor before a disturbance – before land is cleared : which organisms live there and how the ecosystem will be affected

Long-term monitoring programs Amphibians (frogs, toads, salamanders) are common around the world – they are also very sensitive to environmental change. If there is too much change, amphibians will not be able to survive This makes them a good indicator species to help us monitor the overall health of our environment

Baseline Data Many changes occur in an environment after a natural event. In order for scientists to understand any changes that may occur, they need to know what the habitat was like before the disturbance. Baseline data gives scientists a starting point to compare changes

Permanent Plots Scientists often use permanent plots, or study areas, to monitor change Scientists and governments will set aside areas of land that remain untouched so that studying the ecosystem can occur and provide baseline data. Reports that are prepared to outline how an activity will affect the environment is called an Environmental Impact Assessment.