Biodiversity and ecosystem productivity vary greatly across different habitats on Earth. If you’re pressed for time, tropical rainforests rank as the planet’s most productive habitats thanks to abundant sunlight, rainfall, and nutrient recycling.
But productivity depends on how it’s measured – in terms of total biomass, the open ocean tops rainforests.
In this nearly 3,000 word guide, we’ll explore Earth’s major habitat types and compare their productivity by different metrics. We’ll also overview key factors that allow certain habitats to support more life than others.
By the end, you’ll have a comprehensive understanding of our planet’s most and least productive natural environments.
Defining and Measuring Habitat Productivity
Biomass Production
Biomass production refers to the total amount of organic matter produced in an ecosystem over a given period of time, usually annually. It is an important measure of habitat productivity as it represents the capacity of plants in that habitat to capture and store energy from sunlight via photosynthesis.
Habitats with high rates of biomass production, such as tropical rainforests, tend to support more animal life.
Some key metrics used to quantify biomass production include:
- Net primary productivity (NPP) – the net amount of carbon dioxide fixed by plants per unit area over a time period, minus the plants’ own respiration requirements
- Net ecosystem productivity (NEP) – NPP minus the respiration of heterotrophs in the ecosystem
- Standing crop biomass – the total biomass of plants and animals present in an ecosystem at a given point in time
Tools like satellite remote sensing are now allowing more accurate global mapping of variables like NPP, giving new insight into the planet’s most highly productive habitats.
Biodiversity
Biodiversity refers to the total variety of species present within an ecological community or habitat type. Habitats with high species diversity, such as coral reefs, tend to be very productive as different species occupy complementary ecological niches and make efficient use of available resources.
Metrics for quantifying biodiversity include:
- Species richness – the total number of species present
- Species evenness – how evenly population sizes are distributed among the species present
- Genetic diversity within species
- Taxonomic or phylogenetic diversity – accounting for diversity across evolutionary lineages, not just species numbers
High-diversity systems with many complex interconnections tend to be more resilient to disturbance. Preserving biodiversity is key to maintaining productive habitats.
Net Primary Productivity
As mentioned above under biomass production, net primary productivity or NPP represents the net carbon captured by plants in an ecosystem, minus losses to plant respiration. It is typically measured in units of carbon or biomass per unit area per year.
NPP drives the capacity of habitats to support consumer organisms.
Some key facts about global NPP patterns:
- Approximately half of the Earth’s total NPP occurs on land, and about half in the oceans
- Tropical rainforests have very high NPP, up to ~1000-2000 g C/m2/year
- Coral reefs have among the highest NPP of any marine habitat, up to ~1500-3500 g C/m2/year
- Global terrestrial NPP is estimated at ~56 billion tonnes of carbon per year
| Habitat | Net Primary Productivity |
| Tropical rainforest | ~1000-2000 g C/m2/year |
| Temperate forest | ~500-1500 g C/m2/year |
| Boreal forest | ~100-500 g C/m2/year |
| Coral reef | ~1500-3500 g C/m2/year |
| Open ocean | ~50-500 g C/m2/year |
Mapping global NPP distributions using satellite data informs models of habitat productivity and carbon cycling across terrestrial and marine ecosystems.
Most Productive Habitats
Tropical Rainforests
Tropical rainforests, found near the equator, are the most biodiverse habitats on Earth (WWF). Despite covering less than 2 percent of the planet’s surface area, rainforests are home to over half of the world’s plant and animal species.
The hot and humid climate, along with abundant rainfall and dense vegetation, creates ideal conditions for life to thrive. An incredible 15 million species of plants and animals are estimated to live in tropical rainforests (The Nature Conservancy).
Coral Reefs
Although coral reefs occupy less than 1 percent of the ocean floor, they support about 25 percent of all marine life (NOAA). Their complex structures provide food, shelter and breeding grounds for thousands of species like fish, lobsters, sea turtles, sharks and sea birds.
The breathtaking Great Barrier Reef along Australia’s northeast coast is the world’s largest coral reef system. Despite threats from climate change and human activity, coral reefs remain incredibly productive marine ecosystems.
Coastal Estuaries
Estuaries form where rivers meet the sea. Their nutrient-rich waters provide nursery and feeding grounds for many commercial fish species. In fact, over 75 percent of U.S. commercial fish catches originate from estuaries (NOAA).
They also filter pollutants and reduce erosion from rivers before they reach the ocean. Notable estuaries like Chesapeake Bay and San Francisco Bay support diverse plant and animal life while serving vital ecological and economic functions.
Open Ocean
| Percent of Earth’s Surface Covered | 90% |
| Percent of Earth’s Habitable Space | 99% |
| Number of Species | Over 2 million |
The open ocean far from land covers most of our planet, harboring a fascinating web of life. While ocean expanses appear empty, microscopic phytoplankton support all marine food chains. Pelagic predators like tuna, swordfish and sea turtles migrate vast distances in search of prey.
The ocean also absorbs huge amounts of carbon dioxide from the atmosphere, greatly slowing climate change. Although remote, the productivity of Earth’s open seas is truly astounding!
Moderately Productive Habitats
Temperate Forests
Temperate forests, found in mid-latitude regions, are moderately productive due to seasonal changes. These forests have four distinct seasons – spring, summer, autumn and winter. Deciduous trees lose their leaves in fall and regrow them in spring to adapt to the cold winters.
According to the World Wildlife Fund, major temperate forest regions cover the mid-latitudes of North America, Europe and Asia.
The moderate year-round temperatures and precipitation in temperate zones allow for trees like oak, maple, beech and pine to thrive. Wildlife native to these forests includes deer, foxes, bobcats and migratory songbirds. Temperate forests are home to a diversity of plants and animals.
However, they are less productive than tropical rainforests which receive abundant sunlight and rainfall year-round.
Savannas
Savannas are grassland ecosystems characterized by scattered individual trees and shrubs. They are found in Africa, South America and Australia in regions with seasonal rainfall patterns. Savannas have wet summers and dry winters.
According to National Geographic, these grassy plains cover almost 20% of the Earth’s land surface.
With only 6 months supporting plant growth each year, savannas are much less productive than rainforests but slightly more so than deserts. The main plants are different types of grasses while small trees like acacia provide shade and food.
Large migratory herbivores graze on the grasses, including zebras, elephants and giraffes. Other animals found here are big cats like lions and hyenas.
Wetlands
Wetlands include areas like marshes, swamps and bogs covered by water for all or part of the year. The consistently moist conditions allow for a diversity of aquatic plants like cattails, water lilies and rice to grow. But wetlands generally receive fewer sunlight hours than rainforests.
According to the Environmental Protection Agency, wetlands cover about 5-8% of the Earth’s land and freshwater surface.
Fish, frogs, turtles and water birds thrive in these habitats rich in nutrients and minerals. But drier conditions in summer result in lower ecosystem productivity compared to the humid tropics. Climate change threatens many natural wetlands across with pollution and habitat loss trends.
Less Productive Habitats
Deserts
Deserts are extremely dry regions that receive very little rainfall. The lack of water makes them less capable of supporting plant and animal life. However, deserts are not completely lifeless. Specialized plants like cacti and animals like camels have adaptations that allow them to survive in the harsh conditions.
According to the U.S. Geological Survey, deserts cover about one-fifth of the Earth’s land surface. Some of the major deserts include the Sahara Desert in Africa, the Gobi Desert in Asia, the Great Victoria Desert in Australia, and the Mojave Desert in North America.
Tundra
The tundra is a cold, treeless region found in the Arctic and on the tops of mountains. The average winter temperature is below freezing, and the soil is permanently frozen. This restricts drainage and makes it hard for plants to grow roots.
As a result, tundra is much less productive than other biomes.
However, during the short summer, melting allows a burst of productivity. Low-growing plants like mosses, lichens, grasses, and shrubs are able to grow quickly before the winter returns. Animals like caribou, arctic foxes, and snowy owls are well-adapted to the extreme conditions.
Alpine
Alpine regions refer to the high mountain terrain above treeline. At these elevations, low temperatures, high winds, intense sunlight, and rocky soils make growing conditions inhospitable. Trees cannot grow, so alpine areas have sparse, low vegetation consisting mainly of small plants and wildflowers.
Still, alpine animals like mountain goats, bighorn sheep, marmots, and pikas thrive here. These species have thick fur and other evolutionary adaptations to handle the cold. Though production is limited, alpine zones contribute to biodiversity and provide water resources through mountain snowpack and glaciers.
Conclusion
While the tropics contain Earth’s most productive habitats by measures like total biomass and species diversity, no single environment monopolizes productivity. Temperate and even extreme environments make vital contributions too, especially regarding functions like carbon sequestration.
Productivity depends greatly on how it’s defined and habitats have inherent trade-offs. For example, deserts produce little biomass but may have higher net primary productivity than rainforests during wet periods.
Understanding these nuances provides deeper insight into the forces driving life across our planet’s diverse ecosystems.
