B\u00fcy\u00fck memelilerin ge\u00e7mi\u015fte soyunun t\u00fckenmesiyle ilgili bir incelemeye g\u00f6re, fil gibi b\u00fcy\u00fck kara hayvanlar\u0131 ve Afrika antilopu gibi dev ot\u00e7ullar korunmaya de\u011fer. Bunun bir sebebi, yok olmalar\u0131n\u0131n, beraber varolduklar\u0131 bitki ve hayvanlar \u00fczerindeki kal\u0131c\u0131 etkisi.<\/p>\n
Kaliforniya Berkeley, Stanford, \u015eili ve Kaliforniya Sakramento \u00dcniversiteleri\u2019nden paleontologlar, 15.000 y\u0131l \u00f6nce Amerika k\u0131tas\u0131na insanlar\u0131n yerle\u015fmesinden beri b\u00fcy\u00fck hayvan topluluklar\u0131n\u0131n t\u00fckenmesinin ekosistemdeki etkilerini ara\u015ft\u0131rd\u0131. Bulgulara g\u00f6re mamut ve mastodon gibi en b\u00fcy\u00fck kara hayvanlar\u0131n\u0131n yok olmas\u0131n\u0131n ard\u0131ndan, b\u00f6lgenin do\u011fas\u0131nda uzun s\u00fcren de\u011fi\u015fimler meydana geldi.<\/p>\n
\u00d6rne\u011fin, yeni ara\u015ft\u0131rmalar Alaska ve Yukon\u2019da verimli orman ve \u00e7ay\u0131rlar\u0131n verimsiz tundralara d\u00f6n\u00fc\u015fmesinin mamut, yerel at ve di\u011fer b\u00fcy\u00fck hayvanlar\u0131n soyunun t\u00fckenmesi sebebiyle ger\u00e7ekle\u015fti\u011fine i\u015faret ediyor. UC Berkeley\u2019de biyoloji profes\u00f6r\u00fc ve \u00e7al\u0131\u015fman\u0131n y\u00fcr\u00fct\u00fcc\u00fcs\u00fc Anthony Barnosky, benzer \u015fekilde Kuzeybat\u0131 Pasifik ve Kuzeydo\u011fu ABD\u2019de, mamut ve mastodonlar\u0131n t\u00fckenmesinin bitki \u00f6rt\u00fcs\u00fcn\u00fc de\u011fi\u015ftirdi\u011fini ve Bat\u0131 ABD\u2019de k\u00fc\u00e7\u00fck memeli \u00e7e\u015fitlili\u011fini azaltt\u0131\u011f\u0131n\u0131 belirtiyor.<\/p>\n
Barnosky diyor ki, \u201cBug\u00fcn [besin zincirinden] yukar\u0131daki bir y\u0131rt\u0131c\u0131y\u0131 veya anahtar konumdaki bir ot\u00e7ulu \u00e7ekip al\u0131rsan\u0131z, \u00e7evre sisteme belirgin de\u011fi\u015fimler getirdi\u011finizi ekolojik \u00e7al\u0131\u015fmalar g\u00f6steriyor. Ara\u015ft\u0131rmam\u0131z, ge\u00e7mi\u015fte bu gibi de\u011fi\u015fimlerin biny\u0131llarca s\u00fcregeldi\u011fini a\u00e7\u0131k\u00e7a ortaya koydu. Soy t\u00fckenmeleri ger\u00e7ekten dinamikleri kal\u0131c\u0131 bi\u00e7imde de\u011fi\u015ftiriyor. Geri d\u00f6n\u00fc\u015f\u00fcn\u00fcz yok.\u201d<\/p>\n
Ancak bulgulara g\u00f6re nesil t\u00fckenmelerinin hepsi ekosistemde b\u00fcy\u00fck de\u011fi\u015fimler b\u0131rakm\u0131yor. \u00d6rne\u011fin, yer tembel hayvan\u0131 ve gliptodonlar\u0131n yok olmas\u0131 G\u00fcney Amerika\u2019da Patagonya ve Pampalar b\u00f6lgelerindeki bitki \u00f6rt\u00fcs\u00fcnde fark edilebilir bir etkiye yol a\u00e7mam\u0131\u015ft\u0131r.<\/p>\n
Barnosky\u2019ye g\u00f6re, \u201cB\u00fcy\u00fck bir hayvan\u0131 sahneden silince tabiatta \u00f6nemli de\u011fi\u015fiklikler meydana geliyor gibi basit bir hik\u00e2ye yok. De\u011fi\u015fikli\u011fin olup olmayaca\u011f\u0131 silinen hayvan\u0131n b\u00fcy\u00fckl\u00fc\u011f\u00fcne, hayvan\u0131n hangi bitki ve hayvanlarla etkile\u015fim i\u00e7inde oldu\u011funa ve b\u00f6lgede ba\u015fka hangi bitki ve hayvanlar\u0131n mevcut oldu\u011funa ve hayvan\u0131n ya\u015famak i\u00e7in ne yapt\u0131\u011f\u0131na ba\u011fl\u0131.\u201d<\/p>\n
Yaprak yiyici filler<\/strong><\/p>\n \u00d6rne\u011fin mamut, mastodon ve g\u00fcn\u00fcm\u00fcz filleri gibi b\u00fcy\u00fck yaprak yiyiciler k\u00fc\u00e7\u00fck a\u011fa\u00e7lar\u0131, \u00e7al\u0131lar\u0131 yiyip, a\u011fa\u00e7lar\u0131 s\u00f6kt\u00fckleri gibi topra\u011f\u0131 \u00e7i\u011fneyip kar\u0131\u015ft\u0131r\u0131yor. Bizon ve s\u0131\u011f\u0131n gibi di\u011fer b\u00fcy\u00fck ot\u00e7ullar beslenme ve bo\u015falt\u0131m yaparken, \u00e7al\u0131lar\u0131 kontrol alt\u0131nda tutup topraktaki yap\u0131y\u0131 ve besinleri d\u00f6n\u00fc\u015ft\u00fcr\u00fcyor. Sonu\u00e7 olarak, ara\u015ft\u0131rma ekibinin bulgular\u0131na g\u00f6re, bu gibi b\u00fcy\u00fck c\u00fcsseli bitki yiyiciler ormanlar\u0131n \u00e7ay\u0131ra d\u00f6nmesini \u00f6nlemede \u00f6nemli bir rol oynuyor.<\/p>\n Ara\u015ft\u0131rma ekibinden UC Paleontoloji M\u00fczesi Y\u00f6neticisi ve biyoloji profes\u00f6r\u00fc Charles Marschall diyor ki, \u201cG\u00fcn\u00fcm\u00fczde fil topluluklar\u0131 gibi Afrika hayvanlar\u0131n\u0131n yok edilmesinin, \u00e7al\u0131 ve d\u00fczensiz akasyalarla dolu bir bozk\u0131r \u00f6rt\u00fcs\u00fcne yol a\u00e7t\u0131\u011f\u0131n\u0131 g\u00f6r\u00fcyorsunuz. Fil topluluklar\u0131yla g\u00fcn\u00fcm\u00fcz Afrikas\u0131, mamut ve mastodonlu Kuzey Amerika tipiyle \u00f6rt\u00fc\u015f\u00fcyor.\u201d<\/p>\n Arjantin\u2019de Pampalar b\u00f6lgesinde ise, G\u00fcney Amerikal\u0131 mastodonlar\u0131n yok olmas\u0131 bitki ve hayvan topluluklar\u0131n\u0131n \u00fczerinde, muhtemelen hava ko\u015fullar\u0131 ve ya\u011f\u0131\u015f miktar\u0131 ormanlara yeterli oldu\u011fu i\u00e7in g\u00f6zle g\u00f6r\u00fcl\u00fcr bir etki yaratmad\u0131.<\/p>\n Makalenin yazarlar\u0131ndan UC Berkeley\u2019de doktora sonras\u0131 ara\u015ft\u0131rmac\u0131 Emily Lindsey\u2019ye g\u00f6re, \u00e7evre koruma \u00e7abalar\u0131n\u0131 y\u00f6nlendirirken bu ili\u015fkileri anlamak \u00f6nemli olabilir. \u201cKoruma biyologlar\u0131, hangi t\u00fcr ekosistemlerin k\u00fcresel iklim de\u011fi\u015fikli\u011finden en \u00e7ok etkilenece\u011fini ve koruma, restorasyon \u00e7abalar\u0131na duyarl\u0131l\u0131klar\u0131n\u0131 incelerken bu bilgiler faydal\u0131 olabilir.\u201d<\/p>\n Barnosky, Lindsey ve arkada\u015flar\u0131, ara\u015ft\u0131rmalar\u0131n\u0131 Proceedings of the National Academy of Scicences <\/em>dergisinin erken \u00e7evrimi\u00e7i s\u00fcr\u00fcm\u00fcnde yay\u0131mlad\u0131lar.<\/p>\n Ekosistemdeki t\u00fcm de\u011fi\u015fimler fosillerde iz b\u0131rakmad\u0131\u011f\u0131ndan, Barnosky bu \u00e7al\u0131\u015fman\u0131n yaln\u0131zca devasa \u00e7evresel de\u011fi\u015fimleri ve bunlardan b\u00fcy\u00fck memeli nesillerinin t\u00fckenmesinden kaynaklananlar\u0131 kapsad\u0131\u011f\u0131na dikkat \u00e7ekiyor. \u201cG\u00f6rd\u00fc\u011f\u00fcm\u00fcz tesiri g\u00f6rebilmemiz ger\u00e7e\u011fi, bu hayvanlar\u0131n yok olmas\u0131yla ekosistemlerin sonsuza kadar de\u011fi\u015fti\u011fi sonucunu sa\u011flamla\u015ft\u0131r\u0131yor. G\u00fcn\u00fcm\u00fczde \u00e7evrebilimcilerin g\u00f6sterdi\u011fi gibi, ne zaman b\u00fcy\u00fck bir hayvan\u0131 ekosistemden \u00e7\u0131kar\u0131rsan\u0131z, bunun muazzam etkileri oluyor. Ancak bu etkiler her zaman fosil kay\u0131tlarda fark edilemeyebiliyor.\u201d<\/p>\n \u0130nsan\u0131n yeni d\u00fcnyay\u0131 istilas\u0131n\u0131n ard\u0131ndan nesiller t\u00fckendi<\/strong><\/p>\n Barnosky bu ara\u015ft\u0131rma i\u00e7in Amerika b\u00f6lgesinden geyik, kanada geyi\u011fi veya Afrika\u2019dan Afrika antilopunu \u00e7\u0131karman\u0131n etkilerini ara\u015ft\u0131ran ekolojik \u00e7al\u0131\u015fmalar\u0131n esin kayna\u011f\u0131 oldu\u011funu s\u00f6yl\u00fcyor. 15.000 y\u0131l kadar \u00f6nce Sibirya\u2019dan Kuzey ve G\u00fcney Amerika\u2019ya insanlar\u0131n varmas\u0131yla b\u00f6lgede dola\u015fan b\u00fct\u00fcn b\u00fcy\u00fck kara memelilerinin yakla\u015f\u0131k d\u00f6rtte \u00fc\u00e7\u00fcn\u00fcn yok olmas\u0131n\u0131n b\u0131rakt\u0131\u011f\u0131 izleri, ara\u015ft\u0131rma ekibi aramaya karar verdi. Yakla\u015f\u0131k 12.000 y\u0131l \u00f6nce, avlanma ve iklim de\u011fi\u015fimi gibi olas\u0131 sebeplerle 60 memeli t\u00fcr\u00fc Kuzey Amerika\u2019dan silindi. Mamut, mastodon, at, Kanada geyi\u011fi ve ayr\u0131ca et\u00e7il olarak k\u0131l\u0131\u00e7 di\u015fli kedi ve deh\u015fetli kurt yok oldu.<\/p>\n G\u00fcney Amerika\u2019daki t\u00fcrlerin t\u00fckenmesi daha uzun s\u00fcrd\u00fc, ancak bu k\u0131tada sonunda lama, dev armadillo, k\u0131l\u0131\u00e7 di\u015fli kedi, dev yer tembel hayvan\u0131 ve mastodonun akrabas\u0131 Gomphotheriidae<\/em> gibi yakla\u015f\u0131k 99 t\u00fcr yok oldu.<\/p>\n Kuzey Amerika\u2019da \u00fc\u00e7 b\u00f6lgede -Kuzeybat\u0131 Amerika, Kuzeydo\u011fu Amerika ve Alaska\/Yukon\u2019da- yang\u0131n s\u0131kl\u0131\u011f\u0131yla beraber bitki topluluklar\u0131n\u0131n de\u011fi\u015fti\u011fi ve k\u00fc\u00e7\u00fck memeli \u00e7e\u015fitlili\u011finin azald\u0131\u011f\u0131, fosillerde g\u00f6zlemlendi. \u00d6rne\u011fin, \u00e7al\u0131\u015fman\u0131n e\u015f-yazarlar\u0131ndan Stanford \u00dcniversitesi\u2019nde profes\u00f6r Elizabeth Hadly\u2019nin ara\u015ft\u0131rmas\u0131na g\u00f6re, bu yok olu\u015flar\u0131n ard\u0131ndan k\u00fc\u00e7\u00fck kemirgen \u00e7e\u015fitlili\u011finin azalmas\u0131, yayg\u0131n \u201cyabani ot\u201d fare t\u00fcrlerinin t\u00fcm alan\u0131 sarmas\u0131na sebep oldu.<\/p>\n Hadly\u2019ye g\u00f6re, \u201cKuzey Amerika\u2019n\u0131n bize verdi\u011fi mesaj, hortumlular gibi soyu t\u00fckenen b\u00fcy\u00fck hayvan topluluklar\u0131n\u0131n otlama ve yaprak yeme faaliyetleri ya\u015fam alan\u0131 mozaiklerine yard\u0131mda bulundu. Buzul \u00c7a\u011f\u0131\u2019n\u0131n sonuna do\u011fru bu ekosistem m\u00fchendislerinin nesli t\u00fckendi\u011finde, her y\u0131l yapra\u011f\u0131n\u0131 d\u00f6ken ormanlar \u00e7evreye yerle\u015fti. Kuzeybat\u0131 Amerika\u2019da Buzul \u00c7a\u011f\u0131 ya\u015fam alanlar\u0131n\u0131n kaybolmas\u0131, k\u00fc\u00e7\u00fck memeli \u00e7e\u015fitlili\u011finin azalmas\u0131na yol a\u00e7t\u0131.\u201d<\/p>\n Barnosky, \u201cE\u011fer bug\u00fcn yok olma tehlikesindeki b\u00fcy\u00fck hayvanlardan baz\u0131lar\u0131n\u0131 kaybedersek, bu hayvanlardan \u00e7ok daha fazlas\u0131n\u0131, hayvanlar\u0131n ait oldu\u011fu ekosistemi kaybediyoruz\u201d diye belirtiyor.<\/p>\n <\/p>\n Kaynaklar:<\/strong><\/p>\n –<\/strong> http:\/\/www.sciencedaily.com\/releases\/2015\/10\/151026171759.htm<\/p>\n –<\/b>\u00a0http:\/\/news.berkeley.edu\/2015\/10\/26\/loss-of-large-land-mammals-could-change-landscapes-forever\/<\/p>\n","protected":false},"excerpt":{"rendered":" B\u00fcy\u00fck memelilerin ge\u00e7mi\u015fte soyunun t\u00fckenmesiyle ilgili bir incelemeye g\u00f6re, fil gibi b\u00fcy\u00fck kara hayvanlar\u0131 ve Afrika antilopu gibi dev ot\u00e7ullar korunmaya de\u011fer. Bunun bir sebebi, yok olmalar\u0131n\u0131n, beraber varolduklar\u0131 bitki ve hayvanlar \u00fczerindeki kal\u0131c\u0131 etkisi. Kaliforniya Berkeley, Stanford, \u015eili ve Kaliforniya Sakramento \u00dcniversiteleri\u2019nden paleontologlar, 15.000 y\u0131l \u00f6nce Amerika k\u0131tas\u0131na insanlar\u0131n yerle\u015fmesinden beri b\u00fcy\u00fck hayvan topluluklar\u0131n\u0131n […]<\/p>\n","protected":false},"author":917,"featured_media":16626,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[179,19,21,217],"tags":[1983,198,1984,274,449],"class_list":["post-3920","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-142-sayi","category-bilim-gundemi","category-biyoloji","category-cevre-bilimleri","tag-bitki-ortusu","tag-cevre","tag-dogal-durum","tag-dunya","tag-memeliler"],"acf":[],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/bilimvegelecek.com.tr\/index.php\/wp-json\/wp\/v2\/posts\/3920","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/bilimvegelecek.com.tr\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/bilimvegelecek.com.tr\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/bilimvegelecek.com.tr\/index.php\/wp-json\/wp\/v2\/users\/917"}],"replies":[{"embeddable":true,"href":"https:\/\/bilimvegelecek.com.tr\/index.php\/wp-json\/wp\/v2\/comments?post=3920"}],"version-history":[{"count":0,"href":"https:\/\/bilimvegelecek.com.tr\/index.php\/wp-json\/wp\/v2\/posts\/3920\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/bilimvegelecek.com.tr\/index.php\/wp-json\/wp\/v2\/media\/16626"}],"wp:attachment":[{"href":"https:\/\/bilimvegelecek.com.tr\/index.php\/wp-json\/wp\/v2\/media?parent=3920"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/bilimvegelecek.com.tr\/index.php\/wp-json\/wp\/v2\/categories?post=3920"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/bilimvegelecek.com.tr\/index.php\/wp-json\/wp\/v2\/tags?post=3920"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}