User:Lhughesg/Climax species

Climax species

Climax species, also called late seral, late-successional, K-selected or equilibrium species, are plant species that can germinate and grow with limited resources, like low-sun exposure or low water availability. They are the species within forest succession that are more adapted to stable and predictable environments, and will remain essentially unchanged in terms of species composition for as long as a site remains undisturbed.

The seedlings of climax species can grow in the shade of the parent trees, ensuring their dominance indefinitely. A disturbance, such as fire, may kill the climax species, allowing pioneer or earlier successional species to re-establish for a time. They are the opposite of pioneer species, also known as ruderal, fugitive, opportunistic or R-selected species, in the sense that climax species are good competitors but poor colonizers, whereas pioneer species are good colonizers but poor competitors.

The presence of climax species can reduce the prevalence of other species and their dominance within an ecosystem.However, disturbances, such as fires, storms, or droughts, can reduce the abundance of climax species, thus allowing other species, namely pioneer species, to establish the land again before climax species become abundant. In addition to disturbances promoting species diversity by allowing more pioneer species to develop, the age of a successional ecosystem increases species diversity. As ecosystems progress toward later successional stages, the appearance of climax species allows other species to develop that cannot tolerate the high sun-exposure that pioneer species can tolerate.

An image of ecological succession, starting with pioneer species and ending with an old-growth forest that is dominated by climax species.

Given the prevailing ecological conditions, climax species dominate the climax community. When the pace of succession slows down as a result of ecological homeostasis the maximum permitted biodiversity is reached. Their reproductive strategies and other adaptive characteristics can be considered more sophisticated than those of opportunistic species.

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Examples

White spruce is a climax species in the Northern forests of North America. Due to its ability to adapt to low resource available, stable conditions, it dominates Northern forest ecosystems in the absence of a disturbance.

Other examples are:

• Canadian hemlock
• Pacific silver fir
• White fir
• Yellow carabeen
• Blue grama
• Douglas fir
• Coast redwood
• European beech