Carrying capacity • Carrying capacity refers to the number of individuals who can be supported in a given area within natural resource limits, and without degrading the environment for present and future generations.
Carrying capacity may include .. Carrying Capacity may be Physical capacity Ecological capacity Emotional or psychological capacity See diagram of graph…. • Food • Water • Building materials • Waste processing • Leisure Space
WHAT IS A SUSTAINABLE YIELD? • It means that there is balance between what we take from the environment and what it can naturally replenish. • The yield could refer to plants, trees, animals, fish. • Maximum sustainable yield (MSY) means the amount that can be taken without affecting natural replacement.
MAXIMUM SUSTAINABLE YIELD Pop at year end must = or exceed the Pop at start Final pop = Start pop + Growth – mortality & take If the result is positive then the MSY has not been exceeded. If it is negative the MSY has been exceeded.
Ecological Footprint • The demands that one individual makes on the environment. • Demands include: • Water • Food • Energy • Space • Waste disposal
The Ecological Deficit • is the level of resource consumption and waste discharge by a population in excess of local carrying capacity • Questions: • Have we reached a global ecological deficit? • If not, Can you identify any areas that are in deficit
The trend • Over centuries humans have taken more and more from the planet • Because there are more humans • And we each have more impact or footprint • We have been borrowing sun energy from the past – fossil fuels