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| title | chunk | source | category | tags | date_saved | instance |
|---|---|---|---|---|---|---|
| Fire ecology | 4/7 | https://en.wikipedia.org/wiki/Fire_ecology | reference | science, encyclopedia | 2026-05-05T07:18:10.171501+00:00 | kb-cron |
== Species Richness == Species richness is at its peak post-fire but steadily declines over time. Post-fire endurance for certain species allows for a variety of different life histories to exist at the same time. Fires result in a change of biodiversity by reducing the population for the promotion of growth for species. Disturbances due to fire allow for an alternative recovery process for certain animal populations, which can result in recolonization and population growth. Post-fire has decreased the abundance of species and the result of extinction. The effects of burning depend on the size, timing, and severity of the burn. The increased frequency and the size of a fire can impact how a population recovers between other fire events, which causes a patch between population distributions . Fires have been used to alter species composition, such as suppressing species that are invasive.
== Examples of fire in different ecosystems ==
=== Forests ===
Mild to moderate fires burn in the forest understory, removing small trees and herbaceous groundcover. High-severity fires will burn into the crowns of the trees and kill most of the dominant vegetation. Crown fires may require support from ground fuels to maintain the fire in the forest canopy (passive crown fires), or the fire may burn in the canopy independently of any ground fuel support (an active crown fire). High-severity fire creates complex early seral forest habitat, or snag forest with high levels of biodiversity. When a forest burns frequently and thus has less plant litter build-up, below-ground soil temperatures rise only slightly and will not be lethal to roots that lie deep in the soil. Although other characteristics of a forest will influence the impact of fire upon it, factors such as climate and topography play an important role in determining fire severity and fire extent. Fires spread most widely during drought years, are most severe on upper slopes and are influenced by the type of vegetation that is growing.
==== Forests in British Columbia ==== British Columbia represents about 10% of the land area of Canada and yet harbours 70% of the bird and terrestrial mammal species which breed there. Natural fire regimes are important in maintaining a diverse assemblage of vertebrate species in up to twelve different forest types in British Columbia. Different species have adapted to exploit the different stages of succession, regrowth and habitat change that occurs following an episode of burning, such as downed trees and debris. The characteristics of the initial fire, such as its size and intensity, cause the habitat to evolve differentially afterwards and influence how vertebrate species are able to use the burned areas. The change in forest fire intensity over time has been studied for the period since 1600 in an area of central British Columbia and is consistent with fire suppression since regulation was introduced.
==== Siberian Taiga ==== The northern part of the Siberian Taiga, in northern Asia, is covered in permafrost and has minimal human settlements. Larch covers about 80% of the permafrost-zone forested area and has the highest burned area out of all the forest types in the Siberian Taiga, with a relative burned area at 1.13% per year from 1996 to 2019. Wildfires are a natural process in this area, and, particularly in the northern region, are commonly ignited by lightning. Fires in the northern region promote larch growth by clearing the moss ground cover. This process increases the seasonal thawing, adds nutrients to the ground, and gives seeds access to the soil.
=== Shrublands ===
Shrub fires typically concentrate in the canopy and spread continuously if the shrubs are close enough together. Shrublands are typically dry and are prone to accumulations of highly volatile fuels, especially on hillsides. Fires will follow the path of least moisture and the greatest amount of dead fuel material. Surface and below-ground soil temperatures during a burn are generally higher than those of forest fires because the centers of combustion lie closer to the ground, although this can vary greatly. Common plants in shrubland or chaparral include manzanita, chamise and coyote brush.
==== California shrublands ==== California shrubland, commonly known as chaparral, is a widespread plant community of low growing species, typically on arid sloping areas of the California Coast Ranges or western foothills of the Sierra Nevada. There are a number of common shrubs and tree shrub forms in this association, including salal, toyon, coffeeberry and Western poison oak. Regeneration following a fire is usually a major factor in the association of these species.
==== South African Fynbos shrublands ==== Fynbos shrublands occur in a small belt across South Africa. The plant species in this ecosystem are highly diverse, yet the majority of these species are obligate seeders, that is, a fire will cause germination of the seeds and the plants will begin a new life-cycle because of it. These plants may have coevolved into obligate seeders as a response to fire and nutrient-poor soils. Because fire is common in this ecosystem and the soil has limited nutrients, it is most efficient for plants to produce many seeds and then die in the next fire. Investing a lot of energy in roots to survive the next fire when those roots will be able to extract little extra benefit from the nutrient-poor soil would be less efficient. It is possible that the rapid generation time that these obligate seeders display has led to more rapid evolution and speciation in this ecosystem, resulting in its highly diverse plant community.