Question

How does height above sea level affect the kind of biome present?

Short answer

Higher altitudes lead to cooler climates, resulting in distinct biomes like alpine tundra at higher elevations and forests at lower elevations.

Step-by-step solution

Understand the Concept of Biomes

Biomes are large ecological areas on the earth's surface that are defined by their vegetation, climate, and wildlife. Each biome has specific environmental conditions that determine the types of plants and animals that can thrive there.

Recognize the Influence of Altitude on Climate

Height above sea level, or altitude, significantly influences climate. As altitude increases, temperature generally decreases, leading to changes in climate. This affects the types of vegetation that can survive in higher altitudes.

Identify Changes in Vegetation with Altitude

At lower altitudes, warmer temperatures allow for forested biomes such as tropical rainforests and deciduous forests. As altitude increases, the cooler temperatures shift biomes to temperate forests, then to alpine tundra, which can only support hardy vegetation like shrubs and grasses.

Examine the Gradient of Biomes with Altitude

The transition from one biome to another as altitude increases is known as an altitudinal zonation. For example, a mountain may begin with a tropical forest at its base, shift to temperate and boreal forests, and finally reach alpine tundra or permanent ice near the summit.

Analyzing the Relationship Between Altitude and Biome

As altitude increases, each level of elevation supports a distinct community of flora and fauna adapted to those specific climatic conditions. This results in different biomes being present at different altitudes on a mountain or region based purely on environmental suitability.

Key concepts

Altitude and climate

Altitude plays a crucial role in determining the climate of a region. As you move higher above sea level, the temperature tends to decrease. This is why mountain tops are often cooler than their bases. For every 1,000 meters (or about 3,280 feet) you ascend, the temperature drops approximately by 6.5°C (\( ext{or } 11.7°F \).
There are several reasons for this temperature change:

• Air pressure decreases with altitude, which leads to the expansion and cooling of air molecules.
• Thinner atmospheres at higher altitudes allow more heat to escape into space.
• Less horizontal or surface heat movement vertically as it dissipates through the particles in the atmosphere.

As a consequence of these factors, the climates at the bottom and top of a mountain can be vastly different, affecting the local ecosystem and the types of plants and animals it supports.

Vegetation changes with altitude

As altitude increases, the environment becomes less hospitable for some plant species due to the colder temperatures, lower humidity, and potentially higher winds at the top of mountains. This causes a noticeable change in the types of vegetation that can survive as you move up.
At lower elevations, where it is warmer and conditions are more favorable, you might find lush forests with tall trees and diverse plants.

• Tropical rainforests dominate lowland areas in warm-wet climates.
• Temperate forests are usually found in mid-altitude regions.

With further increases in altitude, the vegetation shifts to support only those plants that are tough and can withstand harsher climates:

• Alpine tundra is characterized by shrubs, heath, grasses, and mosses.
• The highest points may support only lichens and hardy grasses.

This progression showcases how adaptable life is to varying environmental conditions and how these factors affect species distribution.

Altitudinal zonation

Altitudinal zonation refers to the division of ecosystems into different zones based on altitude. Each zone represents a distinct climate and thus a distinct ecological community. As you ascend a mountain, the changes in climate create distinct layers of vegetation, similar to traveling from the equator to the poles across Earth's surface.
A typical mountain might show these zones:

• Base: This area may be warm and humid, home to tropical forest biomes.
• Middle slopes: Here, you might find temperate forests with deciduous trees.
• Higher up: Boreal forests might be present before transitioning to alpine tundra.
• Summit: Only hardy plants or even permanent ice, depending on the height of the mountain.

The transition between each zone isn't abrupt but rather a gradual change where the conditions from one zone slowly give way to those of the next. This zoning is crucial for understanding biodiversity patterns on mountains and predicting how climate change might alter these bands.