Enviro 101 Lecture Notes: Economy, Population, and Ecosystems

Population and Environment

Demographics are crucial for understanding the relationship between our economy, land use, and environment. Population growth impacts resource consumption and environmental investment. A decline in population might lead to reduced environmental spending, affecting vulnerable endemic species and broader environmental controls.

Economy and Land Use

New Zealand's economy heavily relies on agriculture. Significant changes in exports (milk, tourism, etc.) have transformed land use, creating environmental issues like pollution. The import economy, driven by fossil fuels and cars, significantly impacts the environment, posing challenges for sustainable practices.

Ecosystems

An ecosystem consists of a biological community and its physical environment, including biotic (plants, animals) and abiotic (water, nutrients) components. Ecology focuses on species interactions and habitat preservation. Terrestrial ecosystems in Aotearoa are classified using climate, temperature, and moisture. DOC recognizes 152 types. Some ecosystems are categorized as zonal (climate-dominated) or azonal (extreme environments).

Trophic Levels and Food Webs

Trophic levels describe an organism's feeding level in an ecosystem, including producers (autotrophs) and consumers (herbivores, carnivores, omnivores). Decomposers recycle nutrients. The loss of tertiary consumers in Aotearoa significantly affected ecosystems. Food webs illustrate interconnected feeding relationships. Understanding these webs, especially at microscopic levels, is crucial. Removing top predators like perch can have unforeseen consequences on the food web, requiring careful assessment.

Ecological Niches

Ecological niches refer to the roles species play in an ecosystem. In Aotearoa, missing mammals led birds and insects to fill niches. Introduced species and ecosystem changes impact these niches, with challenges in restoring ecosystems to pre-human states.