|
Annual Grasslands
Annual grasslands are a type of grassland ecosystem characterized by the dominance of annual grasses and forbs. They are most commonly found in regions with Mediterranean climates, such as California, and provide important habitats for a variety of wildlife species. Annual grasslands have a history of disturbance factors, including grazing, crop production, fire, and drought, which have contributed to the conversion of native perennial grasslands to non-native annual-dominated grasslands. Management issues in annual grasslands include carbon sequestration, native grass restoration, invasive species control, and land use change. Characteristics Annual grasslands are dominated by non-native annual grasses and forbs, with a few native perennial grass species present. These grasslands are subject to seasonal and yearly variations in species composition and productivity, which are largely controlled by the timing and amount of precipitation and temperature. Vegetation dynamics L ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Grassland
A grassland is an area where the vegetation is dominance (ecology), dominated by grasses (Poaceae). However, sedge (Cyperaceae) and rush (Juncaceae) can also be found along with variable proportions of legumes such as clover, and other Herbaceous plant, herbs. Grasslands occur naturally on all continents except Antarctica and are found in most ecoregions of the Earth. Furthermore, grasslands are one of the largest biomes on Earth and dominate the landscape worldwide. There are different types of grasslands: natural grasslands, semi-natural grasslands, and agricultural grasslands. They cover 31–69% of the Earth's land area. Definitions Included among the variety of definitions for grasslands are: * "...any plant community, including harvested forages, in which grasses and/or legumes make up the dominant vegetation." * "...terrestrial ecosystems dominated by herbaceous and shrub vegetation, and maintained by fire, grazing, drought and/or freezing temperatures." (Pilot Assessm ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Habitat Fragmentation
Habitat fragmentation describes the emergence of discontinuities (fragmentation) in an organism's preferred environment (habitat), causing population fragmentation and ecosystem decay. Causes of habitat fragmentation include geological processes that slowly alter the layout of the physical environment (suspected of being one of the major causes of speciation), and human activity such as land conversion, which can alter the environment much faster and causes the extinction of many species. More specifically, habitat fragmentation is a process by which large and contiguous habitats get divided into smaller, isolated patches of habitats. Definition The term habitat fragmentation includes five discrete phenomena: * Reduction in the total area of the habitat * Decrease of the interior: edge ratio * Isolation of one habitat fragment from other areas of habitat * Breaking up of one patch of habitat into several smaller patches * Decrease in the average size of each patch of habit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Legume
Legumes are plants in the pea family Fabaceae (or Leguminosae), or the fruit or seeds of such plants. When used as a dry grain for human consumption, the seeds are also called pulses. Legumes are grown agriculturally, primarily for human consumption, but also as livestock forage and silage, and as soil-enhancing green manure. Legumes produce a botanically unique type of fruit – a simple fruit, simple Dry fruits, dry fruit that develops from a simple carpel and usually Dehiscence (botany) , dehisces (opens along a seam) on two sides. Most legumes have Symbiosis , symbiotic nitrogen fixation , nitrogen-fixing bacteria, Rhizobia, in structures called root nodules. Some of the fixed nitrogen becomes available to later crops, so legumes play a key role in crop rotation. Terminology The term ''pulse'', as used by the United Nations' Food and Agriculture Organization (FAO), is reserved for legume crops harvested solely for the dry seed. This excludes green beans and Pea , green ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Herbicide
Herbicides (, ), also commonly known as weed killers, are substances used to control undesired plants, also known as weeds.EPA. February 201Pesticides Industry. Sales and Usage 2006 and 2007: Market Estimates. Summary in press releasMain page for EPA reports on pesticide use ihere Selective herbicides control specific weed species while leaving the desired crop relatively unharmed, while non-selective herbicides (sometimes called "total weed killers") kill plants indiscriminately. The combined effects of herbicides, nitrogen fertilizer, and improved cultivars has increased yields (per acre) of major crops by three to six times from 1900 to 2000. In the United States in 2012, about 91% of all herbicide usage, was determined by weight applied, in agriculture. In 2012, world pesticide expenditures totaled nearly US$24.7 billion; herbicides were about 44% of those sales and constituted the biggest portion, followed by insecticides, fungicides, and fumigants. Herbicide is also used ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Controlled Burn
A controlled burn or prescribed burn (Rx burn) is the practice of intentionally setting a fire to change the assemblage of vegetation and decaying material in a landscape. The purpose could be for forest management, ecological restoration, land clearing or wildfire fuel management. Controlled burns may also be referred to as hazard reduction burning'', ''backfire'', ''swailing or a burn-off. Controlled burns are conducted during the cooler months to reduce fuel buildup and decrease the likelihood of more dangerous, hotter fires. Controlled burning stimulates the germination of some trees and reveals soil mineral layers which increases seedling vitality. In grasslands, controlled burns shift the species assemblage to primarily native grassland species. Some seeds, such as those of lodgepole pine, sequoia and many chaparral shrubs are pyriscent, meaning heat from fire causes the cone or woody husk to open and disperse seeds. Fire is a natural part of both forest and grass ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Infestation
Infestation is the state of being invaded or overrun by pests or parasites. It can also refer to the actual organisms living on or within a host. Terminology In general, the term "infestation" refers to parasitic diseases caused by animals such as arthropods (i.e. mites, ticks, and lice) and worms, but excluding (except) conditions caused by protozoa, fungi, bacteria, and viruses, which are called infections. External and internal Infestations can be classified as either external or internal with regards to the parasites' location in relation to the host. External or ectoparasitic infestation is a condition in which organisms live primarily on the surface of the host (though porocephaliasis can penetrate viscerally) and includes those involving mites, ticks, head lice and bed bugs. An internal (or endoparasitic) infestation is a condition in which organisms live within the host and includes those involving worms (though swimmer's itch stays near the surface). Somet ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Noxious Weed
A noxious weed, harmful weed or injurious weed is a weed that has been designated by an agricultural or other governing authority as a plant that is harmful to agricultural or horticultural crops, natural habitats or ecosystems, or humans or livestock. Most noxious weeds have been introduced species, introduced into an ecosystem by ignorance, mismanagement, or accident. Some noxious weeds are native, though many localities define them as necessarily being non-native. Typically they are plants that grow aggressively, multiply quickly without natural controls (native herbivores, soil chemistry, etc.), and display adverse effects through contact or ingestion. Noxious weeds are a large problem in many parts of the world, greatly affecting areas of agriculture, forestry, forest management, nature reserves, regional park, parks and other open space. Many noxious weeds have come to new regions and countries through contaminated shipments of feed and crop seeds or were intentionally introd ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Asclepias
''Asclepias'' is a genus of herbaceous, perennial, flowering plants known as milkweeds, named for their latex, a milky substance containing cardiac glycosides termed cardenolides, exuded where cells are damaged. Most species are toxic to humans and many other species, primarily due to the presence of cardenolides. However, as with many such plants, some species feed upon milkweed leaves or the nectar from their flowers. A noteworthy feeder on milkweeds is the monarch butterfly, which uses and requires certain milkweeds as host plants for its larvae. The ''Asclepias'' genus contains over 200 species distributed broadly across Africa, North America, and South America. It previously belonged to the family Asclepiadaceae, which is now classified as the subfamily Asclepiadoideae of the dogbane family, Apocynaceae. The genus was formally described by Carl Linnaeus in 1753, who named it after Asclepius, the Greek god of healing. Flowers Members of the genus produce some of the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amsinckia
''Amsinckia'' is a genus of flowering plants commonly known as fiddlenecks. The common name is Etymology, derived from the flower stems, which curl over at the top in a manner reminiscent of the head of a fiddle. Fiddlenecks are in the family Boraginaceae, along with Borago, borage and Myosotis, forget-me-nots. The genus is named after the patrician Amsinck family in honour of the Hamburg head of state and patron of botany Wilhelm Amsinck (1752–1831). Distribution and description The fiddlenecks are Indigenous (ecology), native to western North America and south-western South America, but they are Naturalisation, naturalized in other regions. They are annual plant, annuals, many of them bristly. Most have an erect stem, whose height varies from 20 to 120 cm. In most species the flowers are yellow, often with an orange tinge. Most are found at relatively low altitudes, below 500 metres. The seeds and foliage of fiddlenecks are poisonous to livestock, particularly ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Poisonous Plants
Plants that cause illness or death after consuming them are referred to as poisonous plants. The toxins in poisonous plants affect herbivores, and deter them from consuming the plants. Plants cannot move to escape their predators, so they must have other means of protecting themselves from herbivorous animals. Some plants have physical defenses such as thorns, spines and prickles, but by far the most common type of protection is chemical. Over millennia, through the process of natural selection, plants have evolved the means to produce a vast and complicated array of chemical compounds to deter herbivores. Tannin, for example, is a defensive compound that emerged relatively early in the evolutionary history of plants, while more complex molecules such as polyacetylenes are found in younger groups of plants such as the Asterales. Many of the known plant defense compounds primarily defend against consumption by insects, though other animals, including humans, that consume such ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Forage
Forage is a plant material (mainly plant leaves and stems) eaten by grazing livestock. Historically, the term ''forage'' has meant only plants eaten by the animals directly as pasture, crop residue, or immature cereal crops, but it is also used more loosely to include similar plants cut for fodder and carried to the animals, especially as hay or silage. While the term ''forage'' has a broad definition, the term ''forage crop'' is used to define crops, annual or biennial, which are grown to be utilized by grazing or harvesting as a whole crop. Common forages Grasses Grass forages include: *''Agrostis'' spp. – bentgrasses **''Agrostis capillaris'' – common bentgrass **''Agrostis stolonifera'' – creeping bentgrass *''Andropogon hallii'' – sand bluestem *''Arrhenatherum elatius'' – false oat-grass *''Bothriochloa bladhii'' – Australian bluestem *''Bothriochloa pertusa'' – hurricane grass *''Brachiaria decumbens'' – Surinam grass *''Brachiaria humidicola'' – kor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Livestock Grazing Comparison
Livestock grazing comparison is a method of comparing the numbers and density of livestock grazing in agriculture. Various units of measurement are used, usually based on the grazing equivalent of one adult cow, or in some areas on that of one sheep. Many different schemes exist, giving various values to the grazing effect of different types of animal. Use Livestock grazing comparison units are used for assessing the overall effect on grazing land of different types of animals (or of mixtures of animals), expressed either as a total for a whole field or farm, or as units per hectare (ha) or acre. For example, using UK government Livestock Units (LUs) from the 2003 scheme a particular pasture field might be able to support 15 adult cattle or 25 horses or 100 sheep: in that scheme each of these would be regarded as being 15 LUs, or 1.5 LUs per hectare (about 0.6 LUs per acre). Different species (and breeds) of livestock do not all graze in the same way, and this is also taken in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
