3.2 Summary: How Human influence Ecosystems  Sustainability: is the ability of an ecosystem to sustain itself or the ability of an ecosystem to continue its existence over time.  Q. How do human effect the sustainability of the ecosystem we live in?

 1. Resource use/Land use: All of the land around us, even in cities, was once a part of an ecosystem (Urbanization)  no longer the original species live there  2. Habitat loss: because of human expansion, habitats have been lost or fragmented. “Habitat fragmentation” : “Habitat fragmentation” : the splitting of large habitats into many smaller ones, resulting in disrupted natural activities for plants and animals. the splitting of large habitats into many smaller ones, resulting in disrupted natural activities for plants and animals.

 3. Deforestation: the more forest we cut down to build industry, the more CO2 we are leaving in the atmosphere because the tress take it out through photosynthesis. Also cause soil degradation  4. The effects of agriculture : soil compaction occurs when soil particles are squeezed together and the air spaces between them particles are reduced  Because of soil compaction water runs off the soil instead of soaking in.

 5. Resource Exploitation: Includes fishing, hunting, mining minerals or growing food. Contamination can occur when harmful chemicals are released into ecosystems as a result of our resources exploitation Includes fishing, hunting, mining minerals or growing food. Contamination can occur when harmful chemicals are released into ecosystems as a result of our resources exploitation  6. Over exploitation: when we use a resource all the way up, it can said to become extinct. Over fishing of cod has reduced its number to less than 90 percent of its original number  7. Traditional ecological knowledge

3.3 How Introduced Species Affect Ecosystems  Native species  Native species naturally live in an area.  Introduced species (aka foreign species, non-native species, exotic species or alien species). –they have been introduced accidentally (& on purpose) here over the past 400 years due to immigration. –Many of these species are harmless, even beneficial. The sea lamprey arrived in the Great Lakes via the canal built between the Great Lakes in estern Canada. The sucker-like “mouth” of the sea lamprey allows the lamprey to attach to this fish. Lampreys suck the body fluid out of fish..

Invasive Species  Invasive : are introduced species that often take advantage of their new habitat. –They may have no predators, are aggressive competitors, & reproduce fast.  Eg. Purple Loosestrife, negatively impacts native species, and often reduces biodiversity as a result.   Biodiversity: varieties of all living species of plants, animals, and microorganisms on Earth. In Europe, the population of purple Loosestrife is controlled by leaf- feeding Beetles. But, here, Native wildlife avoids it.

The impact of Introduced Species: Introduced species can affect native species through competition, predation, disease, parasitism and habitat alteration .  Competition: one species takes away resources from another. 50 breeding pairs of the European Starling were brought to BC in the late 1800’s. It now out-competes western bluebirds for nesting habitat. The American Bullfrog was brought to BC in the 1930’s by restaurants for their legs. It has since taken over the habitats of native frogs.

 if the invasive species is a predator, it may  Predation: if the invasive species is a predator, it may have a huge advantage, as the native species may have no methods to survive.   Disease & Parasitism: by weakening certain species, a micro- organism invading an ecosystem can drastically alter the entire ecosystem and the niches within it. The Norway rat escaped from early European explorer and fur-trading ships. On Queen Charlotte Islands, they have caused a decline in ground-nesting sea birds by eating their eggs and young. West Nile virus was recently introduced to the United States in 1999, when it started causing deaths in birds and illness in humans in New York City. It is a vector borne disease, carried by the mosquito.

 Habitat Alteration: some invasive species can change the physical structure of the ecosystem by digging, burrowing, blocking sunlight or changing the chemistry of the ecosystem. Eurasian Milfoil was first identified in Okanagan Lake in It forms wide, dense mats at lake surfaces, cutting off sunlight to organisms below and interfering with recreational activities. It can grow from plant fragments, which are often spread by boats.