{"id":11890,"date":"2020-07-13T14:19:26","date_gmt":"2020-07-13T12:19:26","guid":{"rendered":"http:\/\/serveiseducatius.xtec.cat\/cda-cansantoi\/?p=11890"},"modified":"2022-10-07T11:26:21","modified_gmt":"2022-10-07T09:26:21","slug":"la-successio-ecologica","status":"publish","type":"post","link":"https:\/\/serveiseducatius.xtec.cat\/cda-cansantoi\/articles-vegetacio\/la-successio-ecologica\/","title":{"rendered":"La successi\u00f3 ecol\u00f2gica"},"content":{"rendered":"<p>&nbsp;<\/p>\n<p>La vegetaci\u00f3 que apareix en un indret va lligada a les condicions ambientals d\u2019aquell lloc. El conjunt d\u2019esp\u00e8cies vegetals particulars que prospera sota aquests condicionants ambientals i que interactuen entre elles constituir\u00e0 el que anomenem una <strong>comunitat vegetal<\/strong>.<\/p>\n<p>Trobem aix\u00ed que per unes determinades condicions ambiental s\u2019hi estableix una comunitat que anomenem potencial o cl\u00edmax i que tendeix a romandre en el temps. Per\u00f2 sovint\u00a0 es produeixen alteracions (tant per causes naturals com antr\u00f2piques) \u00a0que canvien les condicions ambientals i aix\u00f2 provoca la substituci\u00f3 d\u2019unes comunitats per altres m\u00e9s competitives en les noves condicions ecol\u00f2giques. S\u2019instauren noves comunitats que s\u2019anomenen secund\u00e0ries o transit\u00f2ries. A la llarga portaran a\u00a0 la reinstauraci\u00f3 de la comunitat cl\u00edmax<strong>. <\/strong>\u00c9s el que s\u00b4anomena <strong>successi\u00f3. <\/strong>Aquest proc\u00e9s\u00a0 es pot veure alterat per noves pertorbacions. S\u2019estableix aix\u00ed un dinamisme que fa que les comunitats transit\u00f2ries siguin les m\u00e9s abundants\u00a0 en el nostre paisatge, i les comunitats cl\u00edmax siguin escasses.<\/p>\n<p>Cal esmentar que aquestes comunitats transit\u00f2ries, encara que tinguin una vida passatgera, s\u00f3n veritables comunitats i no simples despulles desconjuntades.<\/p>\n<p>D\u2019aquesta manera podem dir que la vegetaci\u00f3 actual \u00e9s un mosaic de comunitats en mutaci\u00f3 permanent.<\/p>\n<p>Sense entrar en el detall de les esp\u00e8cie concretes que hi apareixen, podem simplificar l\u2019aspecte d\u2019una comunitat a tres grans categories: els boscos, les bosquines i els prats.<\/p>\n<p><strong>Bosc<\/strong>: conjunt vegetal on domina l\u00b4estrat arbori per sobre els altres (sotabosc) Hi ha diferents tipus de boscos:<\/p>\n<p>-Arbreda: plantaci\u00f3 forestal on manca el sotabosc<\/p>\n<p>-Boscana: amb sotabosc nom\u00e9s herbaci<\/p>\n<p>-Bosc en galeria: unitat forestal llarga i estreta que ressegueix algun accident geogr\u00e0fic o ecol\u00f2gic<\/p>\n<p>-Bosc baix: format per arbres rebrotats de soca<\/p>\n<p>&nbsp;<\/p>\n<p><strong>Bosquina<\/strong>: conjunt vegetal amb predomini dels arbusts. Segons la densitat i al\u00e7ada distingim:<\/p>\n<p>-M\u00e0quia: conjunt arbustiu alt (1,5~2 m) i for\u00e7a dens<\/p>\n<p>-Brolla: conjunt arbustiu baix (0,5~1 m) i esclarissat.<\/p>\n<p>-Brolla arbrada: brolla a la qual se sobreposa un estrat secundari d\u00b4arbres (generalment pins)<\/p>\n<p>-Garriga: brolla densa amb predomini de garric<\/p>\n<p>-Timoneda: brolla molt baixa (0,2~0,5 m) i fortament esclarissada<\/p>\n<p>-Bardissa: conjunt espin\u00f3s d\u00b4arbustos i lianes, for\u00e7a impenetrable i que forma clapes<\/p>\n<p>&nbsp;<\/p>\n<p><strong>Prat<\/strong>: conjunt vegetal on hi resulten especialment abundants les plantes herb\u00e0cies. Segons les herb\u00e0cies que trobem:<\/p>\n<p>-Herbassar: constitu\u00eft per herbes de bon port i fulla grossa<\/p>\n<p>-Prat: dominat per gram\u00ednies i herbes de fulla prima<\/p>\n<p>-Erm: prat lax amb grans espais sense vegetaci\u00f3<\/p>\n<p>&nbsp;<\/p>\n<p>En la din\u00e0mica que s\u2019estableix en la successi\u00f3 de manera natural apareix la seg\u00fcent s\u00e8rie pel\u00a0 que fa al tipus de vegetaci\u00f3:<\/p>\n<p style=\"text-align: center;\"><strong>PRATS &gt;&gt;&gt;&gt;\u00a0 BOSQUINES &gt;&gt;&gt;&gt;&gt;&gt;\u00a0 BOSCOS<\/strong><\/p>\n<p>A mesura\u00a0 que avan\u00e7a la successi\u00f3:<\/p>\n<ul>\n<li>Trobem esp\u00e8cies m\u00e9s competitives i de creixement m\u00e9s lent<\/li>\n<li>Augmenta la complexitat de la comunitat<\/li>\n<li>Augmenta la biomassa total, sobretot estructural<\/li>\n<li>Augmenta la producci\u00f3 prim\u00e0ria i disminueix la productivitat<\/li>\n<\/ul>\n<figure id=\"attachment_11899\" aria-describedby=\"caption-attachment-11899\" style=\"width: 553px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-11899\" src=\"https:\/\/serveiseducatius.xtec.cat\/cda-cansantoi\/wp-content\/uploads\/usu1385\/2020\/07\/esquema-successio-300x225.jpg\" alt=\"Successi\u00f3 en un alzinar\" width=\"553\" height=\"415\" srcset=\"https:\/\/serveiseducatius.xtec.cat\/cda-cansantoi\/wp-content\/uploads\/usu1385\/2020\/07\/esquema-successio-300x225.jpg 300w, https:\/\/serveiseducatius.xtec.cat\/cda-cansantoi\/wp-content\/uploads\/usu1385\/2020\/07\/esquema-successio-200x150.jpg 200w, https:\/\/serveiseducatius.xtec.cat\/cda-cansantoi\/wp-content\/uploads\/usu1385\/2020\/07\/esquema-successio.jpg 600w\" sizes=\"auto, (max-width: 553px) 100vw, 553px\" \/><figcaption id=\"caption-attachment-11899\" class=\"wp-caption-text\">Successi\u00f3 en un alzinar<\/figcaption><\/figure>\n<p>La vegetaci\u00f3 actual de la serra de Collserola \u00e9s la pr\u00f2pia de les terres baixes mediterr\u00e0nies, afectada fortament, per\u00f2, per la intervenci\u00f3 humana des de temps hist\u00f2rics. (camins, tales, antics conreus&#8230;). A la zona de la Rierada, prop de la riera de Vallvidrera, podem trobar diverses comunitats vegetals influ\u00efdes evidentment per la pres\u00e8ncia propera d\u2019un curs d\u2019aigua, per\u00f2 tamb\u00e9 per factors microclim\u00e0tics en funci\u00f3 del vessant que ocupen a la vall. Les formacions vegetals que hi\u00a0 apareixen s\u00f3n:<\/p>\n<p>&nbsp;<\/p>\n<figure id=\"attachment_11892\" aria-describedby=\"caption-attachment-11892\" style=\"width: 300px\" class=\"wp-caption alignleft\"><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-11892 size-medium\" src=\"https:\/\/serveiseducatius.xtec.cat\/cda-cansantoi\/wp-content\/uploads\/usu1385\/2020\/07\/alzinar-pont08bis-300x225.jpg\" alt=\"Alzinar\" width=\"300\" height=\"225\" srcset=\"https:\/\/serveiseducatius.xtec.cat\/cda-cansantoi\/wp-content\/uploads\/usu1385\/2020\/07\/alzinar-pont08bis.jpg 300w, https:\/\/serveiseducatius.xtec.cat\/cda-cansantoi\/wp-content\/uploads\/usu1385\/2020\/07\/alzinar-pont08bis-200x150.jpg 200w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><figcaption id=\"caption-attachment-11892\" class=\"wp-caption-text\">Alzinar<\/figcaption><\/figure>\n<p>L\u2019alzinar litoral o alzinar amb marfull (comunitat anomenada <em>Viburno-Quercetim ilicis<\/em> antigament coneguda com <em>Quercetum ilicis galloprovinciale<\/em>) correspondria a la comunitat cl\u00edmax. \u00c9s un bosc dens i ombr\u00edvol, dominat per vegetals de fulla perenne i esclerofil\u00b7la, amb \u00a0un sotabosc arbustiu i lianoide ben estructurat.<\/p>\n<p>Sovint els alzinars en proc\u00e9s de recuperaci\u00f3 es desenvolupen sota arbredes de pi blanc, que pel seu car\u00e0cter heli\u00f2fil i creixement r\u00e0pid formen un estrat arbori primerenc. \u00a0Aquests pinedes s\u00f3n transit\u00f2ries ja que quan l\u2019alzinar madura, l\u2019ombra impedeix que els pins \u00a0es regenerin.<\/p>\n<p>&nbsp;<\/p>\n<figure id=\"attachment_11894\" aria-describedby=\"caption-attachment-11894\" style=\"width: 300px\" class=\"wp-caption alignright\"><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-11894 size-medium\" src=\"https:\/\/serveiseducatius.xtec.cat\/cda-cansantoi\/wp-content\/uploads\/usu1385\/2020\/07\/maquia-300x174.jpg\" alt=\"M\u00e0quia\" width=\"300\" height=\"174\" srcset=\"https:\/\/serveiseducatius.xtec.cat\/cda-cansantoi\/wp-content\/uploads\/usu1385\/2020\/07\/maquia-300x174.jpg 300w, https:\/\/serveiseducatius.xtec.cat\/cda-cansantoi\/wp-content\/uploads\/usu1385\/2020\/07\/maquia.jpg 388w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><figcaption id=\"caption-attachment-11894\" class=\"wp-caption-text\">M\u00e0quia<\/figcaption><\/figure>\n<p>&nbsp;<\/p>\n<p>L\u2019alteraci\u00f3 parcial porta cap a un alzinar esclarissat enriquit amb especies heli\u00f2files (com l\u2019arbo\u00e7 i el llentiscle).\u00a0 La p\u00e8rdua total de l\u2019estrat arbori dona pas a una m\u00e0quia densa on predomina l\u2019estrat arbustiu alt.<\/p>\n<p>En un estadi m\u00e9s avan\u00e7at de degradaci\u00f3 hi apareixen les brolles on predomina l\u2019estrat arbustiu baix amb estepes, brucs i roman\u00ed. Quan hi predomina el garric pren el nom de garriga.<\/p>\n<figure id=\"attachment_11895\" aria-describedby=\"caption-attachment-11895\" style=\"width: 300px\" class=\"wp-caption alignleft\"><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-11895 size-medium\" src=\"https:\/\/serveiseducatius.xtec.cat\/cda-cansantoi\/wp-content\/uploads\/usu1385\/2020\/07\/brolla-300x158.jpg\" alt=\"Brolla\" width=\"300\" height=\"158\" \/><figcaption id=\"caption-attachment-11895\" class=\"wp-caption-text\">Brolla<\/figcaption><\/figure>\n<p>En un estadi encara m\u00e9s avan\u00e7at hi trobem les timonedes i els prats secs mediterranis on predomina l\u2019estrat herbaci.<\/p>\n<figure id=\"attachment_11896\" aria-describedby=\"caption-attachment-11896\" style=\"width: 300px\" class=\"wp-caption alignright\"><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-11896 size-medium\" src=\"https:\/\/serveiseducatius.xtec.cat\/cda-cansantoi\/wp-content\/uploads\/usu1385\/2020\/07\/prat-sec-alterat2-300x174.jpg\" alt=\"Prat sec alterat\" width=\"300\" height=\"174\" \/><figcaption id=\"caption-attachment-11896\" class=\"wp-caption-text\">Prat sec alterat<\/figcaption><\/figure>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n","protected":false},"excerpt":{"rendered":"<p>&nbsp; La vegetaci\u00f3 que apareix en un indret va lligada a les condicions ambientals d\u2019aquell lloc. El conjunt d\u2019esp\u00e8cies vegetals particulars que prospera sota aquests condicionants ambientals i que interactuen entre elles constituir\u00e0 el que anomenem una comunitat vegetal. Trobem aix\u00ed que per unes determinades condicions ambiental s\u2019hi estableix una comunitat que anomenem potencial o [&hellip;]<\/p>\n","protected":false},"author":3,"featured_media":11907,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_bbp_topic_count":0,"_bbp_reply_count":0,"_bbp_total_topic_count":0,"_bbp_total_reply_count":0,"_bbp_voice_count":0,"_bbp_anonymous_reply_count":0,"_bbp_topic_count_hidden":0,"_bbp_reply_count_hidden":0,"_bbp_forum_subforum_count":0,"site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"default","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"var(--ast-global-color-4)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"footnotes":""},"categories":[383],"tags":[],"class_list":["post-11890","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-articles-vegetacio"],"post_mailing_queue_ids":[],"_links":{"self":[{"href":"https:\/\/serveiseducatius.xtec.cat\/cda-cansantoi\/wp-json\/wp\/v2\/posts\/11890","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/serveiseducatius.xtec.cat\/cda-cansantoi\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/serveiseducatius.xtec.cat\/cda-cansantoi\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/serveiseducatius.xtec.cat\/cda-cansantoi\/wp-json\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/serveiseducatius.xtec.cat\/cda-cansantoi\/wp-json\/wp\/v2\/comments?post=11890"}],"version-history":[{"count":3,"href":"https:\/\/serveiseducatius.xtec.cat\/cda-cansantoi\/wp-json\/wp\/v2\/posts\/11890\/revisions"}],"predecessor-version":[{"id":11908,"href":"https:\/\/serveiseducatius.xtec.cat\/cda-cansantoi\/wp-json\/wp\/v2\/posts\/11890\/revisions\/11908"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/serveiseducatius.xtec.cat\/cda-cansantoi\/wp-json\/wp\/v2\/media\/11907"}],"wp:attachment":[{"href":"https:\/\/serveiseducatius.xtec.cat\/cda-cansantoi\/wp-json\/wp\/v2\/media?parent=11890"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/serveiseducatius.xtec.cat\/cda-cansantoi\/wp-json\/wp\/v2\/categories?post=11890"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/serveiseducatius.xtec.cat\/cda-cansantoi\/wp-json\/wp\/v2\/tags?post=11890"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}