WWF Terrestrial Ecoregions Collection
Located on the Arabian Peninsula, the Arabian Desert and East Sahero-Arabian Xeric Shrublands , and...
MexicoLast Updated on 2015-02-28 19:15:51Mexico is a North American nation of one hundred and fifteen million people located between the United States to the north and the Central American nations of Guatemala and Belize to the south.
Mexico's main environmental issues include:
scarcity of hazardous waste disposal facilities; rural to urban migration;
scarce and polluted fresh water resources in the northern parts of the country:
inaccessible and poor water quality in central regions and extreme southeast regions;
raw sewage and industrial effluents polluting rivers in urban areas;
deteriorating agricultural lands;
serious air and water pollution in the national capital and urban centers along US-Mexico border; and,
land subsidence in Valley of Mexico caused by groundwater overdrafting.
The Mexican government considers both the lack of clean water and... More »
PredationLast Updated on 2015-02-28 19:11:16
Predation is an interaction between species in which one species uses another species as food. Predation is a process of major importance in influencing the distribution, abundance, and diversity of species in ecological communities. Generally, successful predation leads to an increase in the population size of the predator and a decrease in population size of the prey. These effects on the prey population may then ripple out through the ecological community, indirectly changing the abundances of other species. One example of such indirect effects of predation involves the trophic cascade. As the name implies, a trophic cascade occurs when the effects of predation "cascade" down the food chain to affect plants or other species that are not direcrtly eaten by the predator. Typically, a trophic cascade involves a predator feeding on herbivores and reducing their abundance,... More »
Marine biodiversity and food securityLast Updated on 2015-02-28 19:05:44
Harvesting of wild fish and shellfish from the oceans provides food to the earth’s population, particularly in the developing world, and is a major contributor to the world economy. In the USA alone, fishing supports an industry worth nearly $50 billion annually. Although fishing commenced very early in human history, it was during the 20th century that its reach and impact spread around the globe and into deep waters, first with the advent of motorized vessels near the turn of the century, and later as a result of widespread availability of cheap oil, refrigeration, and increasingly effective technology. These developments made fishing an intensive global industry, particularly after Word War II. Modern fisheries, including both landings and by-catch, currently consume 24-35% of global marine primary production in the continental shelf and major upwelling areas,... More »
Combating Hopping PestsLast Updated on 2015-02-28 18:55:12The Mormon cricket is a voracious feeder that wipes out acres of grasses and field crops in no time. When it’s young, it grows so fast that its immune system cannot keep up. ARS scientists are finding that this may be the best time to use biocontrol fungi to target the insect pest.
New Hopes for Combating Hopping Pests
For many Americans, summertime means warm, sunny days spent by the pool or exploring the country and the world. But for farmers, ranchers, scientists, and state pest control organizations in the western half of the country, summer also means a chance of infestations of hopping pests, particularly grasshoppers and Mormon crickets.
Each adult female grasshopper can lay multiple egg pods—each containing many eggs—in one summer, which could greatly increase the population the next summer, after the eggs hatch. This compounding effect could lead... More »
FungiLast Updated on 2015-02-15 18:00:24The word fungus usually invokes images of mushrooms and toadstools. Although mushrooms are fungi, the forms which a fungus may take are varied. There are over 100,000 species of described fungi and probably over 200,000 undescribed.
Most fungi are terrestrial, but they can be found in every habitat worldwide, including marine (about 500 species) and freshwater environments. Fungi are nonmotile, filamentous eukaryotes that lack plastids and photosynthetic pigments. The majority of fungi are saprophytes; they obtain nutrients from dead organic matter. Other fungi survive as parasitic decomposers, absorbing their food, in solution, through their cell walls.
Most fungi live on the substrate upon which they feed. Numerous hyphae penetrate the wood, cheese, soil, or flesh in which they are growing. The hyphae secrete digestive enzymes that break down the substrate, enabling the fungus to... More »
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