Alpine tundra

**Alpine tundra** wani nau'i ne na yanki na Halitta ko biome wanda ba ya dauke da bishiyoyi saboda yana da tsawo, tare da yanayin da ke da alaƙa. Yayin da latitude na wani wuri ke kusantar sanduna, ƙofar tsawo don tundra na alpine ya ragu har sai ya kai matakin teku kuma ya haɗu da tundra na polar.

Babban tsawo yana haifar da mummunan yanayi, wanda yake da sanyi da iska don tallafawa ci gaban itace. Alpine tundra sauyawa zuwa gandun daji na sub-alpine a ƙasa da layin itace; gandun daji da ke faruwa a cikin gandun daji-tundra ecotone an san su da *krummholz*. Tare da karuwar tsawo ya ƙare a layin dusar ƙanƙara inda dusar ƙara da kankara ke ci gaba a lokacin rani.

Alpine tundra yana faruwa a cikin duwatsu a duk duniya. Tsire-tsire na alpine tundra suna da ƙananan shrubs kusa da ƙasa. Yanayin yanayi na tundra na alpine ya haifar da sanyaya iska, kuma yayi kama da yanayin polar.

## Yanayin ƙasa
Alpine tundra yana faruwa a tsawo mai tsawo a kowane latitude. Sassan tsaunuka na tsaunuka da yankunan daji a duk duniya sun haɗa da tundra na alpine. Manyan yankuna na alpine tundra suna faruwa a cikin Cordillera na Arewacin Amurka da sassa na arewacin Dutsen Appalachian a Arewacin Amurka, Alps da Pyrenees na Turai, Himalaya da Karakoram na Asiya, Andes na Kudancin Amurka, tsaunukan Rift na Gabas na Afirka, Dutsen Snowy na Ostiraliya,    da Dutsen Scandinavia.

Alpine tundra yana zaune a tsaunuka masu tsawo, gangara, da tuddai sama da katako. Asalin yana taka rawa; layin itace sau da yawa yana faruwa a tsaunuka masu tsawo a kan tuddai masu zafi. Saboda yankin alpine yana nan ne kawai a kan duwatsu, yawancin shimfidar wuri yana da tsayi kuma ya karye, tare da dutse, tsaunuka masu dusar ƙanƙara, dutse, da gangaren tuddai, amma kuma ya ƙunshi yankunan da ke juyawa a hankali zuwa kusan shimfidar ƙasa.

Matsakaicin wurare da yawa da microclimates na gida, layin itace ya tashi mita 75 (245  lokacin da yake motsawa digiri 1 kudu daga 70 zuwa 50 ° N, da mita 130 (430  a kowace digiri daga 50 zuwa 30 ° N. Tsakanin 30 ° N da 20 ° S, layin itace kusan ba daidai ba ne, tsakanin mita 3,500 da 4,000 (11,500 da 13,100 . 

## Yanayi

yanayi Alpine shine matsakaicin yanayi (yanayi) don tundra na alpine. Yanayin ya zama mai sanyi lokacin da ya kai tsaunuka masu tsawo - wannan halayyar an bayyana ta hanyar raguwar iska: iska tana da sanyi yayin da yake tashi, tunda yana fadada. Rashin bushewar adiabatic shine 10 ° C a kowace kilomita (5.5 ° F a kowace 1000  na tsawo ko tsawo. Sabili da haka, motsawa sama da mita 100 (330 ft) a kan dutse kusan daidai yake da motsawa kilomita 80 (45 miles ko 0.75 ° na latitude) zuwa ga sanda. Wannan dangantakar tana da kusanci ne kawai, duk da haka, tunda abubuwan da ke cikin gida kamar kusanci da Tekuna na iya canza yanayin sosai.&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;

A cikin tundra mai tsayi, bishiyoyi ba za su iya jure wa yanayin muhalli ba (yawanci yanayin sanyi, matsananciyar dusar ƙanƙara, ko ƙarancin danshi mai alaƙa).  Yawancin lokutan girma masu tsayi suna girma daga kwanaki 45 zuwa 90, tare da matsakaicin yanayin zafi kusa da  . Yanayin yanayin girma yakan faɗi ƙasa da daskarewa, kuma sanyi yana faruwa a duk lokacin girma a wurare da yawa. Hazo yana faruwa ne a matsayin dusar ƙanƙara ta hunturu, amma samun ruwan ƙasa yana da sauƙaƙa sosai tare da yanayi, wuri, da yanayin ƙasa. Misali, filayen dusar ƙanƙara galibi suna taruwa a gefen tsaunin yayin da ridgelines na iya zama kusa da dusar ƙanƙara saboda sake rarrabawa ta iska. Wasu mazaunin tsaunuka na iya zama kusan 70% dusar ƙanƙara a cikin hunturu. Iska mai yawan gaske ya zama ruwan dare a cikin halittu masu tsayi, kuma yana iya haifar da zaizayar ƙasa kuma yana cutar da tsirrai ta zahiri da ta jiki. Har ila yau, iska tare da babban hasken rana na iya haɓaka ƙimar ƙawancen ƙawancen ruwa da haƙori . 

### Ƙididdigar yanayi

An yi ƙoƙari da yawa don ƙididdige abin da ke haifar da yanayin alpine.

Masanin yanayin yanayi Wladimir Köppen ya nuna alaƙa tsakanin layin bishiyoyi na Arctic da Antarctic da isotherm na rani na 10 ° C; watau, wuraren da matsakaicin zafin jiki a cikin watan kalandar mafi zafi na shekara ba zai iya tallafawa gandun daji ba. Dubi Rarrabawar yanayi na Köppen don ƙarin bayani.&nbsp;&nbsp;

Otto Nordenskjöld ya ce yanayin hunturu kuma yana taka rawa: Tsarinsa shine *W* = 9 - 0.1 *C*, inda *W* shine matsakaicin zafin jiki a cikin watanni mafi zafi da *C* matsakaicin watanni mafi sanyi, duka a digiri Celsius (wannan yana nufin, alal misali, idan wani wuri na musamman yana da matsakaicin zafin jiki na  a cikin watansa mafi sanyi, watan mafi zafi zai buƙaci matsakaita  ko sama don bishiyoyi su iya rayuwa a can).

A cikin 1947, Holdridge ya inganta a kan waɗannan tsare-tsaren, ta hanyar bayyana yanayin zafi: matsakaicin zafin jiki na shekara-shekara, inda duk yanayin zafi da ke ƙasa da 0 ° C ana bi da shi a matsayin 0 ° C (saboda ba ya da bambanci ga rayuwar shuka, kasancewa mai barci). Idan matsakaicin yanayin zafi yana tsakanin 1.5 da 3 ° C (34.7 da 37.4 ° F),  Holdridge yana ƙididdige yanayin a matsayin alpine.&nbsp;&nbsp;

## Tsire-tsire

Tunda mazaunin tsire-tsire na alpine yana ƙarƙashin radiation mai ƙarfi, iska, sanyi, dusar ƙanƙara, da kankara, yana girma kusa da ƙasa kuma ya ƙunshi galibi ciyawa, sedges, da kitse="Forb">forbs. Ciyawa masu tsayi (ciki har da ciyawa, sedges, da ƙananan bishiyoyi masu katako ko ƙananan bishiyoyi) sun mamaye yanayin alpine; suna da tushen da rhizome da yawa fiye da na tsiro, ganye, da furanni. Tushen da rhizomes ba kawai suna aiki a cikin ruwa da sinadarin abinci ba har ma suna taka muhimmiyar rawa a cikin ajiyar carbohydrate na hunturu. Tsire-tsire na shekara-shekara ba su da yawa a cikin wannan yanayin halittu kuma yawanci suna da 'yan inci ne kawai, tare da tsarin tushen da ba shi da ƙarfi. Sauran nau'ikan rayuwar shuke-shuke na yau da kullun sun haɗa da shrubs; graminoids masu samar da tussock; tsire-tsire masu tsayi; da cryptogams, kamar Briophytes da lichens.

Dangane da ƙananan yankuna a cikin wannan yankin, yankunan alpine suna da babban adadin endemism da kuma bambancin nau'ikan shuke-shuke. Wannan bambancin taxonomic za a iya danganta shi da keɓewar ƙasa, canje-Canjin yanayi, glaciation, bambancin microhabitat, da tarihin daban-daban na ƙaura ko juyin halitta ko duka biyun. Wadannan abubuwan da suka faru suna ba da gudummawa ga bambancin shuke-shuke ta hanyar gabatar da sabbin tsire-tsire da kuma karɓar sauye-sauye, duka sababbin nau'o'in da suka riga sun kasance.

Shuke-shuke sun saba da yanayin tsaunuka masu tsanani. Tsire-tsire na Cushion, suna kama da tarin mushe na ƙasa, suna tserewa daga iskõki masu ƙarfi da ke hurawa da 'yan inci sama da su. Yawancin tsire-tsire masu fure na alpine tundra suna da gashi mai yawa a kan tsokoki da ganye don samar da kariya ta iska ko launin ja wanda zai iya canza hasken rana zuwa zafi. Wasu tsire-tsire suna ɗaukar shekaru biyu ko fiye don samar da furanni, waɗanda ke tsira daga hunturu a ƙasa sannan su buɗe su kuma su samar da 'ya'yan itace tare da tsaba a cikin 'yan makonni na rani. A wurare daban-daban na tundra na alpine, ana lura da mamayewar shuke-shuke masu katako.

Yankunan tsaunuka na musamman ne saboda tsanani da rikitarwa na yanayin muhallinsu. Ƙananan canje-canje a cikin hoton hoto - ƙanƙanta kamar ƙafa 1 (0.3 m) ko ƙasa da haka - na iya nufin bambanci tsakanin yanki da iska ko yanki na tarin dusar ƙanƙara, yana canza yuwuwar haɓakawa da al'ummar shuka sosai. Tsakanin waɗannan matsananciyar fari tare da jikewa, mahalli da yawa na tsaka-tsaki na iya kasancewa duka a cikin 'yan yadudduka na juna, ya danganta da yanayin ƙasa, ƙasa, da yanayi. Tsarin ciyayi gabaɗaya yana faruwa a cikin mosaic na ƙananan faci tare da bambancin yanayin muhalli. Nau'in ciyayi sun bambanta daga matashin matashin kai da shuke-shuken rosette a kan tudu da kuma a cikin crannies na dutse; zuwa ciyayi masu ciyawa da ciyawa tare da gangaren gangaren; dwarf shrubs tare da ciyawa da hana ƙasa da dusar ƙanƙara mai narkewa; da sedges, ciyawa, ƙananan shrubs, da mosses a cikin bogus da gefen rafi. 

Alpine meadows sun samo asali ne inda turɓaya daga yanayin duwatsu ya samar da ƙasa da ta ci gaba sosai don tallafawa ciyawa da turɓaya. lichens da ba su da fure suna manne wa duwatsu da ƙasa. ƙwayoyin algal da aka rufe zasu iya photosynthesize a kowane zafin jiki sama da  ° C (32 ° F), kuma yadudduka na waje na fungal na iya sha fiye da nauyin su a cikin ruwa. Daidaitawa don rayuwa daga iska mai bushewa da sanyi na iya sa tsire-tsire na tundra su yi kama da tsayi sosai, amma a wasu fannoni tundra yana da rauni sosai. Matakan maimaitawa sau da yawa suna lalata tsire-tsire na tundra, suna ba da damar ƙasa da aka fallasa ta hura; farfadowa na iya ɗaukar daruruwan shekaru.

## Dabbobi

Saboda alpine tundra yana cikin yankuna daban-daban da aka raba da yawa na Duniya, babu nau'in dabba da aka saba da shi ga duk yankunan alpine tundre. Wasu dabbobi na mahalli na alpine tundra sun hada da kea, marmot, awaki na dutse, tumaki na bighorn, chinchilla, Himalayan tahr, yak, leopard na dusar ƙanƙara, da Pika.

## Manazarta