Thicket

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A thicket of silver birch Betula pendula in Saratov Oblast, Russia Betula pendula (fall colors) 2.jpg
A thicket of silver birch Betula pendula in Saratov Oblast, Russia

A thicket is a very dense stand of trees or tall shrubs, [1] [2] often dominated by only one or a few species, to the exclusion of all others. They may be formed by species that shed large numbers of highly viable seeds that are able to germinate in the shelter of the maternal plants.

Contents

In some conditions, the formation or spread of thickets may be assisted by human disturbance of an area. Human disturbance and activity within thickets varies based on culture and location.

Where a thicket is formed of briar (also spelled brier), which is a common name for any of a number of unrelated thorny plants, it may be called a briar patch. Plants termed briar include species in the genera Rosa (Rose), Rubus , and Smilax . [3]

Characteristics

Thickets are characterized by dense plant life, a low closed canopy, deep shale-derived soil, and high levels of soil carbon and nitrogen. [4] Plants present within a thicket generally reach a maximum of 4 to 6 meters in height. [5] The boundaries between a thicket and its nearby forest are defined by a lack of precipitation and overall dry environment within the thicket area, while forests receive higher levels of precipitation. [4] Forests also do not experience as much herbivory and browsing in comparison to thickets. [5]

The thicket biome has been identified in Africa, Madagascar, Australia, North America, [6] and South America. One of the most studied and well-recognized thickets is the Albany thicket biome, located in the Eastern Cape of South Africa.

Due to their overlapping ranges and similarity of plant species, thicket biomes may be misidentified as being portions of savannas. However, these areas can be differentiated through a thicket's lack of C4 grasses [5] and relatively low fire exposure. [4]

Significance and use

Ecological significance

While thickets tend to have a small number of plant species present, as they are often dominated by one species of tree or shrub, the biome provides ecological resources to a large group of species. Thickets frequently make up sections of the home ranges of native species, including ptarmigan and hares in the tundra, [7] cheetahs [8] and lions [9] in Africa, and frogs and alligators in North America. [10] In particular, a thicket's high plant density and resulting low visibility allows for predator species to succeed in tracking, stalking, and capturing their prey. [9]

Societal significance

Especially within the Albany thicket biome, thickets have traditionally been used for raising domestic livestock, although the popularity of doing so is declining over time. [11] Recently, the primary human activity taking place in thickets is game hunting, both for recreational purposes and for ecotourism. The increase in game hunting within thickets has also led to the rise of manmade game farms, which has prompted discussion regarding the impact of game farms on the biome and its health. [11] Conservationists and biologists pose concern about the decrease in biodiversity that game farms may create, especially when coupled with other anthropogenic threats to thickets such as land clearing and urbanization. [12] Alternatively, farmers and many locals suggest that the formation of game farms is an effective manner in which to preserve land area and minimize human impact on a thicket. [11]

Related Research Articles

<span class="mw-page-title-main">Sclerophyll</span> Type of plant/vegetation

Sclerophyll is a type of vegetation that is adapted to long periods of dryness and heat. The plants feature hard leaves, short internodes and leaf orientation which is parallel or oblique to direct sunlight. The word comes from the Greek sklēros (hard) and phyllon (leaf). The term was coined by A.F.W. Schimper in 1898, originally as a synonym of xeromorph, but the two words were later differentiated.

<span class="mw-page-title-main">Grassland</span> Area with vegetation dominated by grasses

A grassland is an area where the vegetation is dominated by grasses (Poaceae). However, sedge (Cyperaceae) and rush (Juncaceae) can also be found along with variable proportions of legumes, like clover, and other 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.

<span class="mw-page-title-main">Savanna</span> Mixed woodland-grassland ecosystem

A savanna or savannah is a mixed woodland-grassland biome and ecosystem characterised by the trees being sufficiently widely spaced so that the canopy does not close. The open canopy allows sufficient light to reach the ground to support an unbroken herbaceous layer consisting primarily of grasses. Four savanna forms exist; savanna woodland where trees and shrubs form a light canopy, tree savanna with scattered trees and shrubs, shrub savanna with distributed shrubs, and grass savanna where trees and shrubs are mostly nonexistent.

<span class="mw-page-title-main">Maputaland–Pondoland bushland and thickets</span> Montane shrubland ecoregion in South Africa

The Maputaland-Pondoland bushland and thickets is one of the ecoregions of South Africa. It consists of the montane shrubland biome.

<span class="mw-page-title-main">Guinean forest–savanna mosaic</span> Tropical forest, savanna, and grassland ecoregion in West Africa

The Guinean forest-savanna, also known as the Guinean forest-savanna transition, is a distinctive ecological region located in West Africa. It stretches across several countries including Guinea, Sierra Leone, Liberia, Ivory Coast, Ghana, Togo, Benin, Nigeria, and Cameroon. This region is characterized by a unique blend of forested areas and savannas, creating a diverse and dynamic landscape.

<span class="mw-page-title-main">Orange-breasted sunbird</span> Species of bird

The orange-breasted sunbird is a species of small, predominantly nectar-feeding bird that is endemic to the fynbos shrubland biome of southwestern South Africa. It is the only member of the genus Anthobaphes, in the family Nectariniidae, though it is sometimes placed in the genus Nectarinia. The birds are sexually dimorphic, with females being olive green while the males are orange to yellow on the underside with bright green, blue and purple on the head and neck.

<i>Leucosidea</i> Genus of flowering plants

Leucosidea sericea, commonly known as oldwood, is an evergreen tree or large shrub that grows in the highland regions of southern Africa. It is the sole species in the monotypic genus Leucosidea. The name oldwood may reflect the fact that the wood burns slowly, as if old and rotting; the gnarled, twisted trunks reinforce this impression.

<span class="mw-page-title-main">Tambourine dove</span> Species of bird

The tambourine dove is a pigeon which is a widespread resident breeding bird in woodlands and other thick vegetation in Africa south of the Sahara Desert. Its range extends from Senegal east to Ethiopia and Kenya and southwards through eastern Africa to south-eastern South Africa, but it is absent from the drier areas of south-western Africa. There is a population on the Comoros Islands.

<i>Choritaenia</i> Genus of flowering plants

Choritaenia capensis is a species of flowering plant in the Apiaceae, of the monotypic genus Choritaenia. It is endemic to central parts of southern Africa. Individuals are usually reported from disturbed areas, such as roadsides, flood plains, and dry dams. It flowers in the spring and early summer. It is distinct for containing several morphological features that are not seen in any of the other genera of the family Apiaceae. Its fruits have a dense vestiture and hygroscopic carpophore that may be an adaptation that allows the plant to respond rapidly to the earliest spring rains.

Vepris heterophylla is an angiosperm belonging to the kingdom Plantae, phylum Tracheophta, class Magnoliopsida, order Sapindales, family Rutaceae., genus Vepris. The genus Vepris is a widespread plant that is capable of adapting to a variety of climatic and soil conditions, drought inclusive Vepris heterophylla can be found in Ghana, Burkina Faso, Cameroon, Mali, and Nigeria, on the African continent. It usually occurs in the dry forest, on rocky hills in the savanna, and on hill slopes with granite boulders and along temporary river banks Vepris heterophylla is listed as an Endangered species according to IUCN Red List Classification due to habitat loss

<span class="mw-page-title-main">Mediterranean forests, woodlands, and scrub</span> Habitat defined by the World Wide Fund for Nature

Mediterranean forests, woodlands and scrub is a biome defined by the World Wide Fund for Nature. The biome is generally characterized by dry summers and rainy winters, although in some areas rainfall may be uniform. Summers are typically hot in low-lying inland locations but can be cool near colder seas. Winters are typically mild to cool in low-lying locations but can be cold in inland and higher locations. All these ecoregions are highly distinctive, collectively harboring 10% of the Earth's plant species.

<i>Thinicola</i> Genus of legumes

Thinicola incana is a species of flowering plant in the legume family, Fabaceae. It is a shrub endemic to central Western Australia. It is the sole species in genus Thinicola, which is in subfamily Faboideae.

Cinnamosma madagascariensis is a species of flowering plant in the family Canellaceae. It is endemic to Madagascar., where it is known as sakaihazo.

The Indian Ocean coastal belt is one of the nine recognised biomes of South Africa. They are described in terms of their vegetation and climatic variations.

Plectranthus ambiguus, the pincushion spurflower, is a species of flowering plant in the family Lamiaceae, native to the Eastern Cape and Kwazulu-Natal provinces of South Africa. Its cultivar 'Manguzuku' has gained the Royal Horticultural Society's Award of Garden Merit. Flowers are pinkish purple with faint purple lines on the upper edge.

<i>Polhillia ignota</i> Flowering plant endemic to the Western Cape

Polhillia ignota is a species of flowering plant in the genus Polhillia. Prior to its rediscovery in September 2016, it was known from two specimens, and declared extinct in 2014. There are only 13 plants known, on a small renosterveld fragment less than 3 ha in size. It is endemic to Eendekuil, in the Western Cape.

<i>Hymenolepis indivisa</i> South African plant species

Hymenolepis indivisa is a species of plant endemic to South Africa.

Thesium goetzeanum is a species of plant from Africa, where it grows between South Africa and Kenya.

Ochna puberula is a shrub or small sized tree with bright yellow petals that are surrounded by green sepals that turn red during fruiting. It belongs to the family Ochnaceae.

References

  1. "Definition of THICKET". www.merriam-webster.com. Retrieved 12 March 2021.
  2. Hoare, David; Mucina, Ladislav; Rutherford, Michael; Vlok, Jan; Euston-Brown, Doug; Palmer, Anthony; Powrie, Leslie; Lechmere-Oertel, Richard; Proches, Serban; Dold, Anthony; Ward, Robert (2006). "Albany thicket biome". The Vegetation of South Africa, Lesotho and Swaziland. Strelitzia. 19: 541–567.
  3. "Definition of BRIAR". www.merriam-webster.com. Retrieved 12 March 2021.
  4. 1 2 3 Cowling, R. M.; Potts, A. J. (2015-11-01). "Climatic, edaphic and fire regime determinants of biome boundaries in the eastern Cape Floristic Region". South African Journal of Botany. Biome Boundaries in South Africa. 101: 73–81. doi: 10.1016/j.sajb.2015.03.182 . ISSN   0254-6299.
  5. 1 2 3 Charles-Dominique, T.; Staver, A. C.; Midgley, G. F.; Bond, W. J. (2015-11-01). "Functional differentiation of biomes in an African savanna/forest mosaic". South African Journal of Botany. Biome Boundaries in South Africa. 101: 82–90. doi: 10.1016/j.sajb.2015.05.005 . ISSN   0254-6299.
  6. Archer, Steve; Scifres, Charles; Bassham, C. R.; Maggio, Robert (1988). "Autogenic Succession in a Subtropical Savanna: Conversion of Grassland to Thorn Woodland". Ecological Monographs. 58 (2): 111–127. doi:10.2307/1942463. hdl: 1969.1/182277 . ISSN   0012-9615. JSTOR   1942463.
  7. Ehrich, Dorothée; Henden, John-André; Ims, Rolf Anker; Doronina, Lilyia O.; Killengren, Siw Turid; Lecomte, Nicolas; Pokrovsky, Ivan G.; Skogstad, Gunnhild; Sokolov, Alexander A.; Sokolov, Vasily A.; Yoccoz, Nigel Gilles (2012-01-01). "The importance of willow thickets for ptarmigan and hares in shrub tundra: the more the better?". Oecologia. 168 (1): 141–151. doi:10.1007/s00442-011-2059-0. ISSN   1432-1939. PMID   21833646.
  8. Bissett, C.; Bernard, R. T. F. (2007). "Habitat selection and feeding ecology of the cheetah (Acinonyx jubatus) in thicket vegetation: is the cheetah a savanna specialist?". Journal of Zoology. 271 (3): 310–317. doi:10.1111/j.1469-7998.2006.00217.x. ISSN   0952-8369.
  9. 1 2 Davies, Andrew B.; Tambling, Craig J.; Kerley, Graham I. H.; Asner, Gregory P. (2016-02-24). "Effects of Vegetation Structure on the Location of Lion Kill Sites in African Thicket". PLOS ONE. 11 (2): e0149098. doi: 10.1371/journal.pone.0149098 . ISSN   1932-6203. PMC   4766088 . PMID   26910832.
  10. Archer, Steve; Scifres, Charles; Bassham, C. R.; Maggio, Robert (1988). "Autogenic Succession in a Subtropical Savanna: Conversion of Grassland to Thorn Woodland". Ecological Monographs. 58 (2): 111–127. doi:10.2307/1942463. hdl: 1969.1/182277 . ISSN   0012-9615. JSTOR   1942463.
  11. 1 2 3 Smith, N; Wilson, S.L. (2002). "Changing land use trends in the thicket biome: pastoralism to game farming". Terrestrial Ecology Research Unit Report. 38: 23.
  12. Palmer, Anthony; Kakembo, Vincent; Lloyd, Wendy; Ainslie, Andrew (2006). "Degradation Patterns and Trends in the Succulent Thicket". Proceedings of the 2004 Thicket Forum.