1.3 Terminology

In this section we look at the effects that changing climatic conditions have on the migration patterns, abundance and distribution patterns of invertebrates, in particular butterflies. Like birds (and all living things), invertebrates are sensitive to changing climatic conditions. Here, we are going to look at why living things are sensitive to changes in environmental conditions.

Let's first look at some of the relevant terminology.

Different species are able to use or tolerate different types of environment – some can stand cold, some can stand hot – and eat different things; they each occupy slightly different ecological niches. Even within a species, individual organisms may well occupy slightly different niches – the town fox and the country fox. This is because they occupy different types of habitat. Some species are highly adaptable; for example, omnivorous rodents like the brown rat can survive on a wide range of foods over a wide range of climate conditions, as can be appreciated by looking at a map of the brown rat distribution.

Some organisms occupy very narrow and particular ecological niches. The range of habitats they occupy is limited, as they require particular environmental conditions – environment is understood as the interrelationship between the living (e.g. plants and animals) and non-living (geology and climate) of a particular place or set of places. A well-known example of an organism that needs a very specific set of environmental parameters to reproduce successfully is the giant panda.

As species extend their range north and begin to change their seasonal distribution, this changes the dynamics within the ecosystems they inhabit. An ecosystem is simply a collection of living things and the environment in which they live. It can be understood at a number of scales, from the rock pool to the North Sea. Different species can inhabit fairly similar ecological niches (e.g. use particular food plants) in which, as long as they live in slightly different habitats, they will not compete for resources. As environments change, habitats change, and this can lead to species migrating into new habitats. If, aside from the occasional periodic climate event, environments are relatively stable over time, or change very slowly, then species have time to adapt to those changing conditions. Rapid changes, like loss of habitat or changing environmental conditions, can lead to the disappearance of a species from an area (locally extinct), from the UK (national extinction) or even lead to species extinction.