Environment

1. Demographic changes – Growth in population is connected to increased resources consumption. This results to activities that result to habitat loss such as intensified use of land, expansion and exploitation of marginal areas of the land
2. Inequality and poverty – in equality in terms of income and the distribution of resources has been blamed for degraded environment. Poverty leads to poor resource management. The governments’ efforts to eliminate poverty has led to construction of dams have great environmental degradation effects.

• Social change - culture influences population, settlement patterns and economic activities that affect the biodiversity. For instance western culture expansion has brought about social change globally with people preferring to reside in urban areas which favor industry over agriculture lead to neglect of traditional cultures that are less destructive to the environment.

1. Climatic changes - These changes results from human activities which interrupt the conditions necessary for plants and animals survival. Such causes include global warming and pollution.
2. Micro-economic policies and structures – these includes policies that tend to favor industrialism and consumerism with little regard on the effect on the environment. An example is policies that encourage oil drilling whose effect on biodiversity is quite significant.
3. Public policies – these are policies put in place which favors the destructive human activities such extensive agricultural activities which can lead to habitat fragmentation. For example –deforestation has great influence on biodiversity.

Invasive species

1. Cane toads - these toads acts like pests and and are known to quickly poison native species
2. Killer algae (Caulerpa) - it spreads quickly and replaces sea-grasses and native algae after crowding them out.

• Carcinus meanas (green crab) – its eating activity greatly impacts on the population of other species such as the mussels, dog whelks and cockles.

1. Zebra Mussel- the species has reduced the availability of food for game and commercial fish and devoured plankton.
2. Sea Walnut- it feeds on zooplznkton consumed by commercial fish and has lead to collapse of local fisheries

 

Endangered species

1. Mexican wolf - the animals decline in numbers is attributed to inbreeding , pups dying before maturity and illegal shooting.
2. Red wolf – the decline in number is mostly attributed to extensive hunting

• California condor- its population decline is attributed to extensive poaching

1. Stella sea lion - population decline is attributed to possible warming in Bearing sea and Gulf of Alaska.