Glossary

 

A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

 

Amensalism

An interaction between two organisms, where one suffers a reduction in resources, or an increase in costs imposed by conditions, due to the presence of another organism. The latter gains no benefit or cost from its interaction with the harmed organism, which distinguishes amensalism from competition, predation or parasitism.

 

Biodiversity

An accepted shortening of the phrase ‘biological diversity’ commonly used to describe species richness. The biological variation found in a defined spatial area: can refer to variation at the level of genome, phenotype, species, community or ecosystem.

 

Climate Change

Long-term changes in the climatic variables experienced in a defined spatial area (which could vary from local weather to global climate). Recent usage refers to recent and future climate change, which is expected to impose stresses on human standard of living and is considered to be the greatest environmental challenge facing the world.

 

Commensalism

This refers to the interaction between two species where one organism gains resources or shelter from conditions, due to the presence of the other species. The latter species gains no benefit or cost from its interaction with the commensal.

 

Community

This refers to all species in a defined spatial area or ecosystem, which interact via trophic, competitive, commensal, amensal or mutualistic interactions. Members of a community may interact directly or indirectly e.g. apparent competition, if they share interaction links to other species in the community.

 

Competition

Competition is the process where organisms gain a greater or lesser share of a limited resource. During exploitation competition, strategies concentrate on the gathering of the resource. During interference competition, organisms engage in strategies that protect their share of the resource for future use, or prevent competitors from exploiting that resource.

 

Ecological niche

The sum total of all the resources used by, and the biotic and abiotic conditions suffered by, a species. Each resource (e.g. food) and condition (e.g. temperature) forms an axis of a multi-dimensional ‘hypervolume’ that describes the ecological requirements and constraints that allow a species to maintain long-term average population growth.

 

Ecology

The scientific study of the distribution, abundance and dynamics of organisms, their interactions with other organisms and with their physical environment.

 

Ecosystem

All organisms and the abiotic environment found in a defined spatial area, generally assumed to be the collective description of a community and its physical environment.

 

Ecosystem Services

Ecosystems have measurable emergent properties, such as productivity, diversity, stability. A subset of these properties can be considered ‘useful’ in some way to human standard of living called ‘ecosystem services’. The phrase is commonly used to help quantify the economic benefits of conserving biodiversity.

 

Evolution

Change in the relative frequencies of heritable genetic information across generations of organisms. This change can be driven by the deterministic process of natural selection, which acts on genetic variation caused by stochastic mutation processes. Or, evolutionary change can occur via stochastic genetic drift in small populations. There exists an important distinction between microevolution, which is change in heritable characteristics within species over short evolutionary timescales, and macroevolution, which is the larger-scale formation of new species during adaptive radiations.

 

Global Warming

A significant, long-term increase in mean global temperatures (air or ocean) during the 20th century, and projected to continue into the future. Commonly used synonymously with climate change, but actually only a subset of the climatic parameters that is predicted to change.

 

Invasive Species

As a broad definition, any species that has recently expanded its realised niche to colonise a new biogeographical area. It is often used synonymously with ‘non-native’. The negative connotations of the word ‘invasive’ makes ‘invasive species’ commonly synonymous with ‘exotic pest’ or ‘exotic weed’, i.e. a species from ‘elsewhere’ that causes harm to human economy or standard of living. Note that only a fraction of non-native species that colonise a new area become established, and that only a fraction of these cause harm to humans or to biodiversity.

 

Mutualism

A biotic interaction between two organisms, where they gain an increase in resources, or a reduction in stressful conditions, from the presence of the other organism. Some mutualisms are obligate, where neither species can exist without the other, while many are facultative, such that the mutualists can persist but with less numerical success in the other’s absence.

 

Parasitism

A trophic interaction in which individuals of one species, called the parasite, feeds upon the tissues of living individuals of another species called the host.

 

Predation

A trophic interaction in which individuals of one species (the predator) kills and eats individuals of the other species (the prey).