Esikhathini lapho ukuguquka kwesimo sezulu kwenza izindawo eziningi zomhlaba zishise futhi zome kakhulu, kuyadabukisa ukucabanga ukuthi izingwadule ziyizinto ezintsha eziphilayo ezikhule kakhulu eminyakeni eyizigidi ezingu-30 edlule. Izindawo ezomile ezisabalele, njengezingwadule namuhla ezihlanganisa ingxenye enkulu yentshonalanga yeNyakatho Melika, zaqala ukuvela phakathi neminyaka eyizigidi ezinhlanu kuya kweziyi-5 edlule.
Ukuqonda ukuthi izitshalo ezihlasele lezi zimila zasogwadule ezinonya zakwazi kanjani ukuphila kungasiza ukubikezela ukuthi imvelo izohamba kanjani esikhathini esizayo esomile.
Ucwaningo olunzulu lweqembu lezitshalo eziqale zahlasela ezisafufusa ugwadule ezigidini zeminyaka edlule iphetha ngokuthi la maphayona—ama-rock daisies—awafikanga engahlomile ukuze abhekane nokushisa, ukushisa kwelanga nokuntuleka kwamanzi. Baye bahlakulela ukuzivumelanisa nezingcindezi ezinjalo ngenkathi behlala ezindaweni ezomile, eziveziwe zamadwala ngaphakathi kwezindawo ezindala, ezinomswakama kakhulu ngisho amahlathi ashisayo, konke lokho kwenza kwaba lula ngabo ukuhlasela izindawo ezomile ezandayo.
IYunivesithi yaseCalifornia, umcwaningi waseBerkeley u-Isaac Lichter-Marck noBruce Baldwin, uprofesa wase-UC Berkeley we-integrative biology, umnakekeli we-Jepson Herbarium kanye nomhleli oyinhloko we "I-Jepson Desert Manual: Izitshalo zeVascular of Southeastern California" (2002), bashicilele ucwaningo lwabo mayelana ukuvela kwama-rock daisies ezingwadule zaseNyakatho Melika kuleli sonto kujenali Izinqubo ze-National Academy of Sciences.
Ucwaningo olokuqala olunikeza ubufakazi bokuxazulula inkulumo-mpikiswano ethathe isikhathi eside yokuziphendukela kwemvelo: Ingabe isithonjana izitshalo zasogwadule, njenge-stately saguaro cacti, i-ocotillos evuthayo kanye nama-agave ase-Seussian avumelana nawo. izimo ezomile kuphela ngemva kokuba behlasele izingwadule, noma bafika sebezijwayelanise nezingcindezi zokuphila ogwadule?
Lo mbuzo ubalulekile namuhla, kusho uLichter-Marck, ngoba ukusheshisa ukomisa ngenxa yokushintsha kwesimo sezulu kuyinselelo yezitshalo ukuzivumelanisa nezimo ngokushesha okukhulu kunangaphambili. Kakade, cishe ingxenye eyodwa kwezinhlanu zomhlaba iwugwadule. Uma ukuzivumelanisa nezimo eziwugwadule kwakungenzeka kuphela ezitshalweni esezivele zashintsha ukuze zibhekane nezingcindezi ezinjalo, abaningi namuhla bangase bangahlonyiselwe ithuluzi elanele lofuzo ukuze baphile.
“Uma ucabanga ngogwadule kuphela njengesisusa sokutshala ukuziphendukela kwemvelo, khona-ke ezimweni eziningi abantu bangase bathi lezi zitshalo ziyaphila, ziyavumelana nezimo, futhi zizolunga. Bazosebenzisa leli thuba ngalezi zimo ezintsha, futhi bazophumelela,” kusho uLichter-Marck, ophinde abe nguzakwabo weNational Science Foundation ocwaningweni ngobudokotela e-UCLA.
Kodwa umlando wama-rock daisies uphakamisa ukuthi “lapho kuvela izingwadule, lezo zitshalo ezazinokujwayela okudingekayo ukuze zisebenzise izimo ezintsha yizo ezachuma,” esho. “Ukwengeza i-aridification eyengeziwe ohlelweni akusho ukuthi ukuguquguquka okuvumelana nezimo kuzokwenzeka. Kunomthombo olinganiselwe wemigqa ongasebenzisa amazinga amasha ogwadule, futhi lokho kubalulekile ekuqondeni umphumela wokuguquka kwesimo sezulu ezinhlobonhlobo zezinto eziphilayo.”
Iminyaka eyisikhombisa ngizulazula ogwadule
Izazi zezitshalo zaqaphela kudala ukuthi lapho izitshalo zihlasela izindawo eziwugwadule, zashintsha ngokushesha ukuze zigcwalise izindawo eziningi ezidalwe yilolu hlobo olusha lwendawo yokuhlala.
“Ngisho namuva nje eminyakeni eyizigidi ezingu-1 kuya kwengu-1.5 edlule, bekungaba nzima ukuthola izindawo zokuhlala eziwugwadule ezisakazeke kabanzi njengoba sizibona namuhla eNyakatho Melika, okumangazayo ngoba manje izingwadule nezindawo eziwugwadule ziyizinto eziphilayo ezisakazeke kakhulu emhlabeni, ” kusho uLichter-Marck. “Kodwa ngasekupheleni kweNkathi yeMiocene, izindawo zokuhlala ezomile zasakazeka, futhi izinhlu zomhlaba zezitshalo zasogwadule, ikakhulukazi izinhlu ezinamanzi ezinjenge-cacti, ama-agave nezitshalo zeqhwa—kanye nezinye izizukulwane eziningi ezibekezelela isomiso—kwaba nokuhlukahluka okusheshayo okuhambisanayo. ”
Nokho, izazi ze-paleontology zabonisa ukuthi izitshalo ezavuvukala ezakhula emashumini ezigidi zeminyaka ngaphambi kokwanda kwezingwadule zazinezici ezifanayo nezezitshalo zasogwadule namuhla. Abanye ososayensi, njengesazi sesayensi yezinto eziphilayo esingasekho emhlabeni uDaniel Axelrod wase-UCLA kanye no-UC Davis, baphikisa ngokuthi lokhu kusho ukuthi izitshalo ezichuma ogwadule namuhla zavela ngaphambili futhi zashintshwa ngaphambi kwesikhathi—noma zakhishwa—ukuze ziphile ezimweni zasogwadule ngokukhula kuma-microsites omile, njenge amadwala, izithunzi zemvula noma iziqongo zezintaba. Abanye, njengo-Ledyard Stebbins ka-UC Berkeley, isazi sokuziphendukela kwemvelo esisize ekutholeni uMnyango Wezofuzo we-UC Davis, baphikisa ngokuthi ugwadule lukhuthaza izitshalo ukuba zihlukanise futhi zithuthukise izici zokumelana nokomisa, ukushisa, ukukhanya kwelanga okunamandla nomoya onamandla.
Naphezu kokufana phakathi kwezindawo ezinamatshe nezingwadule, kube nzima ukufakazela ukuthi izitshalo zasogwadule zivela ezitshalweni ezivele zijwayele ukucindezeleka kogwadule, ngokwengxenye ngenxa yokuthi izinsalela zamathambo akuvamile ukuba zakheke ezindaweni ezomile futhi azikwazi ukusitshela okuningi mayelana nendawo lapho lezi zasendulo zasendulo. izitshalo zazikhula.
Ku-Lichter-Marck no-Baldwin, ama-rock daisies, ahlukaniswa esizweni se-Perityleae emndenini we-sunflower, abonakala njengeqembu elihle lokuhlola ukuxhumana. Ezinye izinhlobo zihlala emadwaleni omile, asobala ezindaweni ezishisayo zaseMexico—okungase kubhekwe “njengezingwadule ezincane”—kuyilapho ezinye sezijwayele ngokuphelele izindawo eziwugwadule, njengeMojave eCalifornia kanye neGreat Basin, Chihuahuan kanye nezingwadule zaseSonoran ezimboze. iningi lasentshonalanga yeNyakatho Melika.
“Izitshalo ezihlala emadwaleni zibhekana nezinselele eziningi ezifanayo nalezo ezihlala endaweni eyomile, ewugwadule,” kusho uLichter-Marck. “Izimo zamadwala zivame ukuchayeka ekukhanyeni kwe-UV, umoya nezomile, izimo ezishisayo, kanye nokushisa nesithwathwa. Zijwayele ukuchayeka kakhulu ezilwaneni ezidla uhlaza.
“Izindlela izitshalo ezibhekana nazo zihlukahlukene, kodwa ngokuvamile zihilela uhlobo oluthile lwezimpande ezikhethekile ezizisiza ukuba zibambelele emadwaleni, kanye nokubhekana nezimo ezinogwadule eziphakeme. Futhi avame ukuba namaqabunga amancane, noma amaqabunga anezinwele eziminyene ezisiza ekuvimbeleni isomiso futhi avimbele ukukhanya kwelanga, kuhlanganise nokukhanya kwe-UV. Futhi bavame ukuvikela amakhemikhali aqinile ezilwaneni ezidla uhlaza, ngoba kuthatha amandla amaningi ukuzivuselela ngemva kokudliwa.”
Ngeziqu zakhe ze-Ph.D. ithesis eMnyangweni Wezinto Ezihlangene Zebhayoloji naseJepson Herbarium, uLichter-Marck, ongowokuzalwa eNingizimu yeCalifornia, wazulazula ogwadule lwase-Arizona, California, Texas naseMexico izinyanga ngesikhathi elolini, ephelezelwa isithende sakhe esiluhlaza, eRio. , ukuqoqa amakhulukhulu ezibonelo zama-rock daises. Amanye ama-rock daisies aphakathi kwezimbali eziqhakaza kakhulu entwasahlobo, ezikhapheza ugwadule ngezimbali ezimibalabala. Nokho, eziningi zilinganiselwe ezindaweni ezincane lapho zikhula khona kuphela emadwaleni aqondile noma eziqhingini zasesibhakabhaka, okuzenza zibe yingozi ukuziqoqa. U-Lichter-Marck ungumqwali wezintaba onesipiliyoni, isethi ebalulekile yamakhono umsebenzi wasensimini ezindaweni ezimbi.
Kamuva wahlela i-DNA yalezi zibonelo—ezingu-73 kwezingu-84 ezaziwayo ze-rock daisy—futhi wabhala umlando wokuphila kwazo, njengokuthi zamila kuphi, hlobo luni lwezimpande ezazinaso, nokuthi zaziwunyaka noma zingapheli, isitshalo noma isihlahla. Wabe esewaqhathanisa nama-daisies anezinsalela zamathambo ukuze akhe umugqa wesikhathi onzima wokuvela kwalezi zici futhi ekugcineni uhlu luguquke lube izingwadule.
Lokhu kwamvumela ukuba aphethe ngokuthi ama-rock daises amaningi—ikakhulukazi, i-Laphamia, okwakungowokuqala ukuthuthela ogwadule futhi ewuhlobo olukhulu kunazo zonke lwama-rock daisy—ayezivumelanise nezimo ezicindezelayo zokushisa, ugwadule, umoya kanye nelanga ngenxa yokushisa kwazo. ukukhula emaweni ngaphambi kokuhlasela izingwadule.
“Lokhu kuwukubonakaliswa okucacile kwalokho okwakuyinkolelo-mbono ka-Axelrod—yeqembu lezitshalo zasogwadule elivela endaweni eyomile ngaphambi kokuvela kwezindawo ezihlala ogwadule,” kusho uLichter-Marck. “Lokhu kusho ukuthini ukuthi amasu okubekezelela isomiso abonakala kakhulu ezitshalweni zasogwadule angase angameleli izimpendulo ezimweni ezomile ezitholakala ogwadule. Esikhundleni salokho, kungaba yizici ezavela ngaphambili ngokuhlangana nezimo zezulu ezomile ezindala nezizinzile, njengamadwala aphuma ezindaweni ezishisayo.”
I-preadaptation ingaba yisihluthulelo sempumelelo yezitshalo eziningi zasogwadule, okuhlanganisa i-cacti, eyaziwa ngokuhlala ezindaweni ezisemaphandleni noma ezikhula njengama-epiphyte emifuleni yezihlahla ezindaweni ezishisayo, nakuba lezi zinhlu ezinkulu zizodinga ukuhlaziywa okunwetshiwe kakhulu, esho. .
Ama-rock daisies, amaningi awo ahlala ezindaweni ezikhethekile eziwenza abe sengcupheni yokushabalala, aqokomisa ukubaluleka kokulondoloza izinto eziphilayo ezibonakala ziyizindathane.
“Ama-rock daisies amaningi akhethekile kakhulu futhi avame ukuba mncane kakhulu ekusatshalalisweni kwawo futhi angase abonakale engabalulekanga kangako ekusindeni kwe-ecosystem iyonke. Kusayensi yokuziphendukela kwemvelo kanye nesayensi yokongiwa kwemvelo, izinto eziphilayo ezikhethekile ezinobubanzi obuncane bendawo ngokuvamile zibhekwa njengezinhlu ezisengozini futhi ngezinye izikhathi ziye zabizwa ngokuthi izinhloso zokuziphendukela kwemvelo,” kusho yena. “Okubalulekile lapha ukuthi iqembu lochwepheshe bezemvelo elikhula emaweni agqagqene ezindaweni ezishisayo laqala le misebe emikhulu ogwadule. Ngakho-ke, empeleni kukhombisa ukuthi ochwepheshe abazona nje lezi zinhlu ezisengozini esemaphethelweni okushabalala. Bangase babe imithombo ebaluleke ngempela yokusungula izinto ezintsha ekuziphendukeleni kwemvelo.”
U-Lichter-Marck njengamanje welula izifundo zakhe ze izitshalo ezimila emadwaleni afika e-Hawai'i, lapho izinhlobo eziningi zezilwane ezitholakala ezindaweni ezihlala kuzo zihlala kuphela emaceleni ezintaba eziwumqansa. Nokho, esikhundleni sokukala amawa ayingozi ukuze afinyelele izibonelo eziyivelakancane, unethemba lokuthi uzosebenzisa ama-drones.