SCENE: Basics of Biodiversity

What is biodiversity?

Biodiversity refers to the variety of life in all its forms, including species diversity, genetic diversity, and ecosystem diversity. It can be defined and measured in different ways depending on the context.

Why is measuring biodiversity difficult?

Because biodiversity can be assessed qualitatively (descriptive) or quantitatively (numerical), and there are multiple dimensions to consider such as species richness, abundance, and evenness.

How can biodiversity be measured?

It can be measured by counting the number of species (species richness), the number of individuals, or using indices like the Shannon-Wiener index, which incorporates both richness and evenness.

What is species richness?

Species richness is the number of different species present in a given area. It does not account for how evenly individuals are distributed among those species.

What is the Shannon-Wiener index?

A common mathematical index used to measure biodiversity. It accounts for both the number of species (richness) and the relative abundance of individuals (evenness).

What are the limitations of diversity indices?

Each index has flaws in sensitivity to data distribution. Therefore, the choice of index depends on the spread and characteristics of the data being analyzed.

What is evenness in biodiversity?

Evenness measures how equally individuals are distributed among the species in a community. An evenness score of 1 means all species have the same number of individuals.

Why is evenness important in assessing biodiversity?

High evenness suggests a more stable and resilient ecosystem, where no single species dominates. It provides a clearer picture of ecological balance.

Has biodiversity always been assumed to be beneficial?

Yes, biodiversity has long been considered inherently good, but for many years this was assumed rather than empirically proven.

How was the relationship between biodiversity and ecosystem function studied?

Scientists like Robert May created computer models simulating ecosystems, and in the 1980s and early 1990s, experiments with real ecosystems were developed to test this link.

What are Ecotrons?

Ecotrons are experimental microcosms—small, enclosed ecosystems—used to test hypotheses about biodiversity. They are typically populated with microorganisms and allow controlled studies of ecosystem processes.

What did Ecotron experiments show about biodiversity?

These experiments revealed that ecosystems with greater biodiversity are generally more stable and resilient, particularly during disturbances such as drought or other environmental stress.

How does biodiversity impact coral reef resilience?

Coral reef systems with greater diversity of species tend to survive better during extreme weather events and periods of environmental stress.

What is the effect of grazer extinction on ecosystems?

The extinction of one grazer species often leads to the extinction of others due to interdependence in ecological roles, reducing ecosystem function.

Are all extinctions unnatural?

No, extinctions are a natural part of evolution, but the current extinction rate is much higher than historical background levels, largely due to human impact.

How is climate change affecting species distribution?

Species are shifting their temperature ranges, often moving to cooler or higher-altitude environments as global temperatures rise.

What is beta diversity?

Beta diversity refers to the difference in species composition between ecosystems or habitats. It helps assess the turnover of species across landscapes but is difficult to measure precisely.

Why is beta diversity important?

It gives insight into how biodiversity varies across space and helps in conservation planning by identifying unique or diverse ecosystems.

What role do large-scale disturbances play in testing biodiversity theories?

Major events such as storms or droughts allow researchers to observe how ecosystems with different levels of biodiversity respond to stress, often revealing that more diverse systems recover better.

Why is it important to study biodiversity through both models and experiments?

Computer models help simulate theoretical outcomes, while real-world experiments validate those models and provide practical insights into ecosystem dynamics.