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Citizen science and global biodiversity
Citizen science and global biodiversity

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6 Interaction of spatial and temporal scales

To have a full understanding of global biodiversity, we need to knit the roles of drivers with their impact across scales of time and space, as they often operate at the same time. Consider for example the impact of lightning causing a forest fire and decimating a rich diversity of reptiles. The fire event could happen within hours, but its impact could destroy the biodiversity of a large area at the landscape level, measured in tens of square kilometres.

In another context, climatic shift may occur gradually, perhaps over decades, to change the local forest biome to a desert and hence impacting an area encompassing tens of thousands of square kilometres – i.e. at the regional scale.

The key message here is the need to understand the time and space scales of environmental drivers and their impacts so that, when investigating environmental issues, cause and effect are considered at the appropriate scale. A hierarchical summary of drivers and impacts across scales of time and space is given in Table 1.

Table 1 Hierarchical framework of temporal and spatial processes influencing species diversity (after Middleton, 2013)
Spatial scaleDominant environmental variablesTemporal scale

Local: within communities, within habitat patches

~0.1–10 km

Fine-scale biotic and abiotic interactions (e.g. habitat structure, disturbance by fires, storms)~1–100 years

Landscape: between communities; turnover of species within a landscape

~10 km–100 km

Soils, altitude, peninsula effect~100–1000 years

Regional: large geographical areas within continents

~100 km–1000 km

Radiation budget and water availability, area, latitudePrevious 10,000 years (i.e. since end of last glacial period)

Continental: differences in species lineages and richness across continents

~1000–5000 km

Aridification events, Quaternary glaciation, interglacial cycles, mountain-building episodes (e.g. Tertiary uplift of the Andes)Previous 1–10 million years

Global: differences reflected in the biogeographical realms (e.g. distribution of mammal families between continents)

~5000–10000 km

Continental plate movements, sea-level changePrevious 10–100 million years