Where is the pollution coming from?
White Snail (Theba pisana) is an introduced
species.
Invasive Species
Post-fire seeding can encourage the spread of invasive weeds. For example, forty-three thousand pounds of non-native rye grass seed (Lolium multiflorum) were donated and distributed throughout San Diego County after the 2003 Cedar Fire. Humans also destroy chaparral to build home sites, suppress fires, and plant grass in burned areas to stabilize the soil and to mitigate future fires. This grass is competition for native chaparral plants. Another concern relating to post-fire seeding practices relates to the introduction of non-native weeds. Although seed companies guarantee their mixes, in practice it has proven impossible to eliminate contamination by alien species. For example, 800,000 pounds of grass seed was aerial seeded over more than 13,400 acres by a BAER effort on the Cerro Grande Fire scar around Los Alamos, New Mexico. It was discovered later that an estimated 1 billion cheat grass seeds (Bromus tectorum) contaminated the seed mix.
Air pollution
Of all the various types of pollution created by humans, none are as destructive to the chaparral as air pollution. Humans tend to develop lands of the chaparral for commercial and residential use because these biomes get a lot of sun, are near the oceans, and have a mild climate year round. With people building homes and industry getting closer to the Chaparral, the air pollution is a big factor. In addition, ozone in smog is becoming more and more present in the Chaparral due to motor vehicles. Ground-level ozone is formed when vehicle emissions containing nitrogen oxides (primarily from vehicle exhaust) and volatile organic compounds (from paints, solvents, and fuel evaporation) interact in the presence of sunlight.
Post-fire seeding can encourage the spread of invasive weeds. For example, forty-three thousand pounds of non-native rye grass seed (Lolium multiflorum) were donated and distributed throughout San Diego County after the 2003 Cedar Fire. Humans also destroy chaparral to build home sites, suppress fires, and plant grass in burned areas to stabilize the soil and to mitigate future fires. This grass is competition for native chaparral plants. Another concern relating to post-fire seeding practices relates to the introduction of non-native weeds. Although seed companies guarantee their mixes, in practice it has proven impossible to eliminate contamination by alien species. For example, 800,000 pounds of grass seed was aerial seeded over more than 13,400 acres by a BAER effort on the Cerro Grande Fire scar around Los Alamos, New Mexico. It was discovered later that an estimated 1 billion cheat grass seeds (Bromus tectorum) contaminated the seed mix.
Air pollution
Of all the various types of pollution created by humans, none are as destructive to the chaparral as air pollution. Humans tend to develop lands of the chaparral for commercial and residential use because these biomes get a lot of sun, are near the oceans, and have a mild climate year round. With people building homes and industry getting closer to the Chaparral, the air pollution is a big factor. In addition, ozone in smog is becoming more and more present in the Chaparral due to motor vehicles. Ground-level ozone is formed when vehicle emissions containing nitrogen oxides (primarily from vehicle exhaust) and volatile organic compounds (from paints, solvents, and fuel evaporation) interact in the presence of sunlight.
What effects will pollution have on the Chaparral?
Invasive grasses are taking over native species
Invasive Species
Post-fire seeding can encourage the spread of invasive weeds, and contribute to the elimination of native plant communities. For example the distribution and ryegrass growth after a Cedar fire was at the expense of native cover with the greatest negative effect being on native, fire-following annuals. The use of ryegrass has also been associated with high mortality of the native Ceanothus shrub seedlings. Also, the invasive cheat grass contaminated a seed mix that was placed throughout the chaparral after a fire. Cheat grass is an extremely invasive alien species that is creating significant ecological damage in many western forests and deserts by increasing fire frequency due to unnatural addition of flashy fuels. Non-native plant species are the most abundant of the three types of exotics in the chaparral, and the most invasive of these are grasses. Many of them do not compete with local species in native habitats, but instead tend to overtake disturbed sites. A few species, however, compete directly with native species. Those specifically invading the montane regions include French broom (Genista monspessulana), which is toxic to humans and livestock, spotted knapweed (Centaurea maculosa), a strong competitor for already scarce moisture and minerals, three species of oats, and cheatgrass (Bromus tectorium), which increases fire frequencies. Many of the invasive plants in the montane chaparral are grasses that can quickly dominate a large area. The thick growth of these grasses uses up resources that could otherwise be used by native species and provides a plentiful and fast-growing fuel for fires. Bullfrogs are also threat near the central California coast, as they predate on smaller, native amphibians. The most serious threat from any invasive species in the ecoregion is from exotic pathogens. Pine pitch canker (Fusarium circinatum) and sudden oak death (Phytophthora ramorum) are fungi that each have the potential to kill members of several different tree species.
Air Pollution
Oxidant air pollution is worse in the Southern California mountains than almost anywhere else in North America. Two species of conifers in these mountains, ponderosa pine (Pinus ponderosa) and Jeffrey pine (P. jeffreyi), are particularly vulnerable to harm from the ozone gas that the air contains. These can include injury to the pine’s foliage ranging from relatively minor harm to abscission (when a plant initiates removal of a particular structure because of disease or extreme damage), crown thinning, and stunted growth. Air pollution, emitted from development also greatly damages mixed conifer and closed-cone pine forests.
Post-fire seeding can encourage the spread of invasive weeds, and contribute to the elimination of native plant communities. For example the distribution and ryegrass growth after a Cedar fire was at the expense of native cover with the greatest negative effect being on native, fire-following annuals. The use of ryegrass has also been associated with high mortality of the native Ceanothus shrub seedlings. Also, the invasive cheat grass contaminated a seed mix that was placed throughout the chaparral after a fire. Cheat grass is an extremely invasive alien species that is creating significant ecological damage in many western forests and deserts by increasing fire frequency due to unnatural addition of flashy fuels. Non-native plant species are the most abundant of the three types of exotics in the chaparral, and the most invasive of these are grasses. Many of them do not compete with local species in native habitats, but instead tend to overtake disturbed sites. A few species, however, compete directly with native species. Those specifically invading the montane regions include French broom (Genista monspessulana), which is toxic to humans and livestock, spotted knapweed (Centaurea maculosa), a strong competitor for already scarce moisture and minerals, three species of oats, and cheatgrass (Bromus tectorium), which increases fire frequencies. Many of the invasive plants in the montane chaparral are grasses that can quickly dominate a large area. The thick growth of these grasses uses up resources that could otherwise be used by native species and provides a plentiful and fast-growing fuel for fires. Bullfrogs are also threat near the central California coast, as they predate on smaller, native amphibians. The most serious threat from any invasive species in the ecoregion is from exotic pathogens. Pine pitch canker (Fusarium circinatum) and sudden oak death (Phytophthora ramorum) are fungi that each have the potential to kill members of several different tree species.
Air Pollution
Oxidant air pollution is worse in the Southern California mountains than almost anywhere else in North America. Two species of conifers in these mountains, ponderosa pine (Pinus ponderosa) and Jeffrey pine (P. jeffreyi), are particularly vulnerable to harm from the ozone gas that the air contains. These can include injury to the pine’s foliage ranging from relatively minor harm to abscission (when a plant initiates removal of a particular structure because of disease or extreme damage), crown thinning, and stunted growth. Air pollution, emitted from development also greatly damages mixed conifer and closed-cone pine forests