Grazing (behaviour)
Grazing is a method of
Grazing's ecological effects can include redistributing nutrients, keeping grasslands open or favouring a particular species over another.
Ecology
Many small selective herbivores follow larger grazers which skim off the highest, tough growth of grasses, exposing tender shoots. For terrestrial animals, grazing is normally distinguished from
Graminivory
Graminivory is a form of grazing involving feeding primarily on grass[4] (specifically "true" grasses in the Poaceae). Horses, cattle, capybara, hippopotamuses, grasshoppers, geese, and giant pandas are graminivores. Giant pandas (Ailuropoda melanoleuca) are obligate bamboo grazers, 99% of their diet consisting of sub-alpine bamboo species.[5]
Cecotrophy
For lagomorphs (rabbits, hares, pikas), easily digestible food is processed in the gastrointestinal tract & expelled as regular feces. But in order to get nutrients out of hard to digest fiber, lagomorphs ferment fiber in the cecum (in the GI tract) and then expel the contents as cecotropes, which are reingested (cecotrophy). The cecotropes are then absorbed in the small intestine to utilize the nutrients. This is a different process than cows chewing the cud, but with similar results.[6]
Capybara (Hydrochoerus hydrochaeris) are herbivores that graze mainly on grasses and aquatic plants,[7][8] as well as fruit and tree bark.[9] As with other grazers, they can be very selective,[10] feeding on the leaves of one species and disregarding other species surrounding it. They eat a greater variety of plants during the dry season, as fewer plants are available. While they eat grass during the wet season, they have to switch to more abundant reeds during the dry season.[11] The capybara's jaw hinge is not perpendicular; hence, it chews food by grinding back-and-forth rather than side-to-side.[12]
Like lagomorphs, capybara create, expel & eat cecotropes (cecotrophy) to get more nutrition from their food. They may also regurgitate food to masticate again, similar to cud-chewing by a cow.[13] As with other rodents, the front teeth of capybara grow continually to compensate for the constant wear from eating grasses.[14] Their cheek teeth also grow continuously.[12]
Pseudoruminant
The hippopotamus is a large, semi-aquatic, mammal inhabiting rivers, lakes and mangrove swamps. During the day, they remain cool by staying in the water or mud; reproduction and childbirth both occur in water. They emerge at dusk to graze on grasses. While hippopotamuses rest near each other in the water, grazing is a solitary activity. Their incisors can be as long as 40 cm (16 in) and the canines (tusks) up to 50 cm (20 in);[15] however, the canines and incisors are used for combat, and play no role in feeding. Hippos rely on their broad, horny lips to grasp and pull grasses which are then ground by the molars.[16] The hippo is considered to be a pseudoruminant; it has a complex three- or four-chambered stomach but does not "chew cud".[17]
Non-grass grazing
Although grazing is typically associated with
Benefits
Environmental
Grazer urine and feces "recycle nitrogen, phosphorus, potassium and other plant nutrients and return them to the soil".[20] Grazing can allow for the accumulation of organic matter which may help to combat soil erosion.[21] This acts as nutrition for insects and organisms found within the soil. These organisms "aid in carbon sequestration and water filtration".[20]
Biodiversity
When grass is grazed, dead litter grass is reduced which is advantageous for birds such as
In North American tallgrass prairies, diversity and productivity are controlled to a large extent by nitrogen availability ... Nitrogen availability in prairies was driven by interactions between frequency of fires and grazing by large herbivores ... Spring fires enhance growth of certain grasses, and herbivores such as bison preferentially graze these grasses, keeping a system of checks and balances working properly, and allowing many plant species to flourish.[23]
References
- ISBN 0-19-861122-6.
- ISBN 0139156534.
- ISBN 0-86542-111-0.
- ^ "Definition of GRAMINIVOROUS". www.merriam-webster.com.
- .
- ^ "Information for Rabbit Owners — Oak Tree Veterinary Centre". Oaktreevet.co.uk. Archived from the original on 2012-06-23. Retrieved 2010-08-30.
- Smithsonian National Zoological Park. Retrieved on December 16, 2007.
- ^ Capybara. Palm Beach Zoo. Retrieved on December 17, 2007.
- S2CID 83976640.)
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: CS1 maint: multiple names: authors list (link - S2CID 84982123.
- ^ a b Capybara. Hydrochaeris hydrochaeris. San Francisco Zoo
- .
- ^ Bristol Zoo Gardens (UK) Capybara Archived 2007-09-18 at the Wayback Machine. Bristolzoo.org.uk. Retrieved on 2011-12-07.
- ISBN 0-520-08085-8.
- ISBN 0-226-43722-1.
- ISBN 0-85661-131-X.
- ^ Begon, M., Townsend, C. and Harper, J. (1996). Ecology (3 ed.). Blackwell Science, London.
{{cite book}}
: CS1 maint: multiple names: authors list (link)[page needed] - S2CID 53074768.
- ^ a b "Benefits of Grazing Cattle on the Prairie". Native Habitat Organization. Retrieved 1 Dec 2008 Archived 2007-03-06 at the Wayback Machine
- ^ Dalrymple, R.L.. "Fringe Benefits of Rotational Stocking". Intensive Grazing Benefits. Noble Foundation. Retrieved 1 Dec 2008 Archived 2008-08-20 at the Wayback Machine
- ^ "Waterfowl area grazing benefits birds, cattle - The Fergus Falls Daily Journal". 21 February 2008.
- ^ "Bison Grazing Increases Biodiversity In ...(Grazing by herbivorous mammals like b...)". news.bio-medicine.org.