Layin itace

Layin itace
biocoenosis (en)
Bayanai
Ƙaramin ɓangare na	border (en) da ecotone (en)
Bangare na	dutse
Fuskar	montane ecosystem (en)

Layin bishiyoyi shine gefen wurin da bishiyoyi zasu iya girma kuma ba zasu iya girma ba. Ana samunsa a manyan tsaunuka da kuma manyan latitudes . Bayan layin bishiyoyi, bishiyoyi ba za su iya jure yanayin muhalli ba (yawanci ƙarancin zafi, dusar ƙanƙara mai yawa, ko rashin danshi da ke tattare da shi). ^:51A wasu lokutan ana bambanta layin bishiyoyi da layin katako na ƙasa, wanda shine layin da ke ƙasa wanda bishiyoyi ke samar da daji mai rufin rufewa. ^{:151 :18}

A layin bishiyoyi, girman bishiyoyi yakan ragu, ya ragu, kuma iska da sanyi sun lalace. Wannan wani lokacin ana kiransa krummholz (Jamusanci don "itacen da aka lanƙwasa"). ^:58

Layin bishiyar sau da yawa yana bayyana a sarari, amma yana iya zama sauyawa a hankali. Bishiyoyi suna girma gajeru kuma sau da yawa suna girma a ƙasa da yawa yayin da suke kusantar layin bishiyoyi, wanda ba za su iya girma ba kwata-kwata. ^:55Idan aka yi la'akari da wani yanki mai faɗi, layin bishiyar yana da tsayin mita 300 zuwa 1000 a ƙasa da layin dusar ƙanƙara na dindindin kuma yana daidai da shi. ^[1]

Saboda tsarinsu a tsaye, bishiyoyi sun fi saurin kamuwa da sanyi fiye da nau'ikan tsire-tsire masu rungumar ƙasa. ^[2] Dumin lokacin rani gabaɗaya yana ƙayyade iyaka ga yadda girmar bishiyoyi zai iya faruwa: yayin da conifers na layin bishiyoyi suna da matuƙar juriya ga sanyi a yawancin shekara, suna jin kamar sanyi yana da digiri 1 ko 2 kawai a tsakiyar lokacin rani. Jerin lokutan bazara masu dumi a shekarun 1940 sun ba da damar kafa "adadi mai yawa" na tsirrai masu tsiro a saman layin bishiyoyin da suka gabata a tsaunuka kusa da Fairbanks, Alaska . ^{[3] [4]} Rayuwa ta dogara ne akan isasshen sabon tsiro don tallafawa bishiyar. Iska na iya lalata kyallen bishiyoyi kai tsaye ta hanyar injiniya, gami da fashewa da ƙwayoyin da ke ɗauke da iska, kuma yana iya taimakawa wajen bushewar ganye, musamman rassan da ke fitowa a saman murfin dusar ƙanƙara. ^[5]

Tsawan layin bishiyoyi a wani wuri gabaɗaya ana saita shi ne ta hanyar matsakaicin zafin jiki, yayin da layin bishiyar da aka gano zai iya shafar matsaloli, kamar sare bishiyoyi, ^[2] ko kiwo. ^[6] Yawancin ayyukan ɗan adam ba za su iya canza ainihin layin bishiyoyi ba, sai dai idan sun shafi yanayi. ^[2] Layin bishiya yana bin layin inda matsakaicin zafin yanayi yake kusan 6 °C (43 °F) . ^{[7] [2]} Ana ɗaukar matsakaicin zafin yanayi a duk kwanakin da matsakaicin zafinsu ya wuce 0.9 °C (33.6 °F) . Ana buƙatar lokacin girma na kwanaki 94 sama da wannan zafin jiki don girmar bishiyoyi. ^[8]

Saboda sauyin yanayi, wanda ke haifar da narkewar dusar ƙanƙara da wuri da kuma yanayi mai kyau don kafa bishiyoyi, layin bishiyoyi a North Cascades National Park ya tashi sama da 400 feet (120 m) a cikin shekaru 50. ^[9]

Wasu abubuwan da ke faruwa a yankin na iya canza tsayin layin bishiyoyi a cikin gida, kamar ɓangaren gangara, inuwar ruwan sama . Layukan bishiyoyi a kan gangaren da ke fuskantar arewa a yankin arewa sun yi ƙasa da na gangaren da ke fuskantar kudu, domin yawan inuwar da ke fuskantar arewa yana nufin cewa dusar ƙanƙara tana ɗaukar lokaci kafin ta narke. Wannan yana rage lokacin girma ga bishiyoyi. ^:109A yankin kudu, gangaren da ke fuskantar kudu suna da ɗan gajeren lokacin girma. A bakin teku da tsaunukan da ke keɓe, layin bishiyoyi galibi yana ƙasa da tsayin da ya dace a cikin ƙasa da kuma a cikin manyan tsarukan tsaunuka masu rikitarwa. Wannan ana kiransa da tasirin Massenerhebung, kuma manyan tsaunuka suna riƙe zafi da rage saurin iska a ƙasa, idan aka kwatanta da tsaunukan da aka keɓe. Bugu da ƙari, a wasu yankuna na wurare masu zafi ko tsibirai, rashin nau'ikan da ke da sauƙin fari da sanyi na iya haifar da ƙananan layukan bishiyoyi fiye da yadda mutum zai zata ta yanayi kaɗai. ^[10]

1. ↑ "Why treelines?".
2. 1 2 3 4 Körner, Christian (November 1, 2021). "The cold range limit of trees". Trends in Ecology & Evolution. 36 (11): 979–989. Bibcode:2021TEcoE..36..979K. doi:10.1016/j.tree.2021.06.011. PMID 34272073 Check |pmid= value (help). S2CID 235999977 Check |s2cid= value (help).
3. ↑ Viereck, L.A. (1979). "Characteristics of treeline plant communities in Alaska". Holarctic Ecology. 2 (4): 228–238. Bibcode:1979Ecogr...2..228V. doi:10.1111/j.1600-0587.1979.tb01294.x. JSTOR 3682417.
4. ↑ Empty citation (help)
5. ↑ Maher, CT; Nelson, CR; Larson, AJ (2019). "Winter damage is more important than summer temperature for maintaining the krummholz growth form above alpine treeline". J Ecol. 108 (3): 1074–1087. doi:10.1111/1365-2745.13315.
6. ↑ Wang, Xiaoyi; Wang, Tao (2022). "Enhanced habitat loss of the Himalayan endemic flora driven by warming-forced upslope tree expansion". Nature Ecology & Evolution. 6 (7): 890–899. Bibcode:2022NatEE...6..890W. doi:10.1038/s41559-022-01774-3. PMID 35654898 Check |pmid= value (help).
7. ↑ Körner, Christian; Paulsen, Jens (May 2004). "A World-Wide Study of High Altitude Treeline Temperatures". J. Biogeogr. 31: 713–732. Bibcode:2004JBiog..31..713K. doi:10.1111/j.1365-2699.2003.01043.x. JSTOR 3554841. S2CID 59025355.
8. ↑ Paulsen, Jens; Körner, Christian (2014). "A climate-based model to predict potential treeline position around the globe" (PDF). Alpine Botany. 124 (1): 1–12. Bibcode:2014AlBot.124....1P. doi:10.1007/s00035-014-0124-0. S2CID 8752987.
9. ↑ "Climate Change Resource Brief - North Cascades National Park". U.S. National Park Service (in Turanci). January 30, 2018. Retrieved May 13, 2025.
10. ↑ Leuschner, Christoph (April 1996). "Timberline and Alpine Vegetation on the Tropical and Warm-Temperate Oceanic Islands of the World: Elevation, Structure and Floristics". Vegetatio. 123 (2): 193–206. doi:10.1007/BF00118271.