The Human Environment Quiz 1

Degraded Habitats

those produced by sporadic, yet incomplete, disturbances; for example, the cutting of a forest, burning and the non-intensive grazing of natural grassland.

Ruderal Habitats

where disturbance is sustained but where there is no intentional substitution of vegetation. Roadsides are an example of a ruderal habitat.

Cultivated Habitats

when constant disturbance is accompanied by the intentional introduction of plants.

Artificial Habitats

which are developed when humans modify the ambient climate and soil, as in greenhouse cultivation.

Natural Habitats

those that develop in the absence of human activities

Agriculture is the biggest degrader of

Land

Climate change is the biggest driver of

increased fires

Debris burning starts the most human-caused fires, standing at

29 percent with arson the cause of 21 percent of fires

Swidden agriculture

a technique of rotational farming in which land is cleared for cultivation (normally by fire) and then left to regenerate after a few years. It can minimize the problems posed by soil fertility deterioration, soil erosion, & vegetation degradation.

Human involvement triggers __ percent of wildfires

84

Fire Deficit

a situation where a region has experienced a significant reduction in the number of wildfires over a long period due to fire suppression efforts

4 ways plants & trees adapt to forest fires

thick bark, serotinous cones, fire-induced sprouts, fire activated seeds

benefits of fires

• Seed germination

• Seedbeds with rich ash, bare soil, or thin humus may be created- Douglas firs & giant sequoias.

• Releases seeds and seems to stimulate the vegetative reproduction of many woody and herbaceous species

• Control forest insects, parasites and fungi

• Stimulate the flowering and fruiting of many shrubs and herbs, and to modify the physicochemical environment of the plants.

• Mineral elements are released both as ash and through increased decomposition rates of organic layers.

• Greater species diversity

the problem with forest fires

it increases the amount of carbon dioxide entering the atmosphere

good sign of a healthy plant

bending

deforestation

the temporary or permanent action of clearing a wide area of trees.

Since pre‐agricultural times world forests have declined approximately _____________. The highest ____ has occurred in temperate forests (32–35%), followed by ___________________

• one‐fifth, from five to four billion hectares

• loss

• sub‐tropical woody savannas and deciduous forests

Palm oil development accounted for an estimated ____ of deforestation

42 percent

A relatively small ecosystem with a high concentration of species, many of which are endemics.

Biodiversity ‘Hot Spot’

what happens if we lose our rainforests

• reduced biological diversity

• changes in local & regional environments

• changes in global environments

No other type of ecosystem provides more benefits for biodiversity, food, weather patterns, fresh water, and human health than ______________.

tropical rainforest