{"id":103821,"date":"2020-06-22T15:21:33","date_gmt":"2020-06-22T22:21:33","guid":{"rendered":"http:\/\/www.lankaweb.com\/news\/items\/?p=103821"},"modified":"2020-06-22T15:21:53","modified_gmt":"2020-06-22T22:21:53","slug":"ancient-sri-lankans-built-canals-their-legacy-today-a-new-type-of-forest","status":"publish","type":"post","link":"https:\/\/www.lankaweb.com\/news\/items\/2020\/06\/22\/ancient-sri-lankans-built-canals-their-legacy-today-a-new-type-of-forest\/","title":{"rendered":"Ancient Sri Lankans built canals. Their legacy today? A new type of forest."},"content":{"rendered":"<h2><span style=\"color: #0000ff;\"><em>by\u00a0<a style=\"color: #0000ff;\" href=\"https:\/\/news.mongabay.com\/by\/malaka-rodrigo\/\" rel=\"tag\" data-wpel-link=\"internal\">Malaka Rodrigo<\/a>\u00a0 Courtesy Mongabay.com<\/em><\/span><\/h2>\n\n\n<figure class=\"wp-block-image\"><img decoding=\"async\" src=\"https:\/\/www.researchgate.net\/publication\/337871160\/figure\/fig1\/AS:834680970551296@1576014859485\/Remains-of-an-ancient-irrigation-tank-functional-during-the-Polonnaruwa-Period-is.png\" alt=\"Remains of an ancient irrigation tank functional during the Polonnaruwa Period, is presently sand-filled and retains only up to one meter-deep water; this wetland habitat is colonized by a grove of Terminalia arjuna (&quot;Kumbuk') trees, mimicking a river forest.\"\/><figcaption> <em>a\u00a0<a rel=\"noreferrer noopener\" href=\"https:\/\/www.researchgate.net\/publication\/337871160_A_new_forest_vegetation_type_in_Sri_Lanka_Dry_Canal-associated_Evergreen_Forest\" target=\"_blank\">dry canal-associated evergreen forest<\/a>\u00a0or canal forest, a new type of forest vegetation discovered from the ancient capital of Polonnaruwa in north-central Sri Lanka, courtesy of Magdon Jayasuriya.<\/em> <\/figcaption><\/figure>\n\n\n\n<ul class=\"wp-block-list\"><li><em>A new type of forest ecology has been discovered from the ancient kingdom of Polonnaruwa in north-central Sri Lanka, centered around the irrigation canals abandoned there more than 700 years ago.<\/em><\/li><li><em>The unique new forest type closely resembles the riverine forests that are found alongside rivers and other bodies of water, but has a different species composition and vegetation structure.<\/em><\/li><li><em>Sri Lanka boasts a legacy of extensive ancient irrigation systems scattered within the island\u2019s dry zone, raising the prospect of the discovery of more of these dry canal-associated evergreen forests.\u201d<\/em><\/li><\/ul>\n\n\n\n<p>POLONNARUWA, Sri Lanka \u2014 For centuries, Sri Lanka\u2019s&nbsp;<a href=\"http:\/\/inwepflanka.org\/hydraulic-civilization\/\" target=\"_blank\" rel=\"noreferrer noopener\">ancient civilization<\/a>&nbsp;diverted river water to large reservoirs and man-made canals for agriculture. After the collapse of the island\u2019s hydraulic civilization about 700 years ago, these canals were abandoned. But water still flows through them today, nurturing a different type of vegetation.<\/p>\n\n\n\n<p>That\u2019s what plant ecologist&nbsp;<a href=\"https:\/\/www.linkedin.com\/in\/magdon-jayasuriya-71834238\/?originalSubdomain=lk\" target=\"_blank\" rel=\"noreferrer noopener\">Magdon Jayasuriya<\/a>&nbsp;discovered when he examined one such abandoned ancient irrigation canal built between the 11th and 14th centuries, historically known as the&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Polonnaruwa_period\" target=\"_blank\" rel=\"noreferrer noopener\">Kingdom of Polonnaruwa<\/a>. The canal was built to divert water from the&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Mahaweli_River\" target=\"_blank\" rel=\"noreferrer noopener\">Mahaweli River<\/a>&nbsp;to a cascade of small reservoirs and farmlands scattered near what is today&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Somawathiya_National_Park\" target=\"_blank\" rel=\"noreferrer noopener\">Somawathiya National Park<\/a>.<\/p>\n\n\n\n<p>It\u2019s here that Jayasuriya has identified a new type of forest vegetation, described in a new&nbsp;<a href=\"https:\/\/cjs.sljol.info\/articles\/abstract\/10.4038\/cjs.v48i4.7679\/\" target=\"_blank\" rel=\"noreferrer noopener\">study<\/a>&nbsp;in the&nbsp;<em>Ceylon Journal of Science<\/em>: <a href=\"https:\/\/www.researchgate.net\/publication\/337871160_A_new_forest_vegetation_type_in_Sri_Lanka_Dry_Canal-associated_Evergreen_Forest\" target=\"_blank\" rel=\"noreferrer noopener\">dry canal-associated evergreen forest<\/a>,\u201d or a canal forest that joins an&nbsp;<a href=\"https:\/\/www.researchgate.net\/publication\/282861229_Natural_vegetation_types_in_dry_zone_of_Sri_Lanka_and_their_characteristics\" target=\"_blank\" rel=\"noreferrer noopener\">already diverse list of forest types found within Sri Lanka\u2019s dry zone<\/a>.<\/p>\n\n\n\n<p>The canal forest closely resembles a riverine forest or dry riverine evergreen forest, but differ in plant species diversity and characteristics. These differences may be because of factors ranging from the water flow, to the availability of groundwater, to the steepness of the banks, Jayasuriya told Mongabay.<\/p>\n\n\n\n<p><strong>Riverine forests<\/strong><\/p>\n\n\n\n<p>Riverine forests, found adjacent to bodies of water, are natural habitats with unregulated natural water flow. The canal forest, by contrast, would have experienced regulated and maintained water flow when the canal was in use, and a less uniform flow after its abandonment. The banks of the canal are also shallower than riverbanks due to seasonal strong and unregulated water flow creating more habitats in the latter and adding more diversity, according to the study.<\/p>\n\n\n\n<p>The canopy of the canal forest appears shorter, too, at about 10-12 meters (33-40 ft), while river forests can grow to heights of about 20-25 m (65-82 ft).<\/p>\n\n\n\n<p>The new forest type is dominated by&nbsp;<em><a href=\"https:\/\/en.wikipedia.org\/wiki\/Vitex_leucoxylon\" target=\"_blank\" rel=\"noreferrer noopener\">Vitex leucoxylon<\/a>,<\/em>&nbsp;a tree known locally as&nbsp;<em>nebada<\/em>&nbsp;and which accounts for more than half of the vegetation.&nbsp;&nbsp;<em><a href=\"https:\/\/en.wikipedia.org\/wiki\/Terminalia_arjuna\" target=\"_blank\" rel=\"noreferrer noopener\">Terminalia arjuna<\/a><\/em>, or&nbsp;<em>kumbuk<\/em>, a tree generally found in greater abundance within river forests, makes up only a fifth of the canal forest vegetation, the study says.<\/p>\n\n\n\n<figure class=\"wp-block-image\"><img decoding=\"async\" src=\"https:\/\/imgs.mongabay.com\/wp-content\/uploads\/sites\/20\/2020\/06\/22112853\/Cover-photo-Cascade-tank-system-768x512.jpg\" alt=\"\" class=\"wp-image-231657\"\/><figcaption><em>Ancient irrigation engineers used canals to divert water to cascading reservoir systems, retaining the water for irrigation purposes. Image courtesy of IUCN Sri Lanka.<\/em><\/figcaption><\/figure>\n\n\n\n<p>Based on detailed analysis of the plant species found within this forest ecology, Jayasuriya said the Polonnaruwa area may have had savanna forests, though there is no direct evidence of such today. Hinting at the possibility of savanna forests in the past, Jayasuriya cites the presence of&nbsp;<em><a href=\"http:\/\/www.flowersofindia.net\/catalog\/slides\/Divine%20Jasmine.html\" target=\"_blank\" rel=\"noreferrer noopener\">Tamilnadia uliginosa<\/a><\/em>&nbsp;and&nbsp;<em><a href=\"https:\/\/en.wikipedia.org\/wiki\/Antidesma_alexiteria\" target=\"_blank\" rel=\"noreferrer noopener\">Antidesma ghaesembilla<\/a><\/em>&nbsp;trees, considered savanna species.<\/p>\n\n\n\n<p>It is possible that over 700 years ago during pre-Polonnaruwa, this canal would have flowed through a savanna forest though it is not present today,\u201d Jayasuriya said.<\/p>\n\n\n\n<p>Jayasuriya said he had to take an uncomfortable tractor journey across&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Somawathiya_National_Park\" target=\"_blank\" rel=\"noreferrer noopener\">Samawathiya National Park<\/a>, lying in the flood plain of the&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Mahaweli_River\" target=\"_blank\" rel=\"noreferrer noopener\">Mahaweli River<\/a>, to study this new vegetation type. Due to time constraints, I couldn\u2019t fully study the forest. As Sri Lanka has lots of ancient irrigational canals and tanks, I\u2019m sure canal forests would exist elsewhere as well, but would have been overlooked,\u201d Jayasuriya said.<\/p>\n\n\n\n<p>He called for further study of this vegetation type in Sri Lanka, with the support of both archaeologists and hydrologists.<\/p>\n\n\n\n<p>The discovery of this new forest vegetation type after a long period is evidence of the possibility of many ecologically important discoveries waiting to be made,\u201d Jayasuriya said, adding that young researchers in particular should delve into the field.<\/p>\n\n\n\n<p><em>Citation:<\/em><\/p>\n\n\n\n<p>Jayasuriya, A. H. M. (2019).A new forest vegetation type in Sri Lanka: Dry canal-associated evergreen forest.&nbsp;<em>Ceylon Journal of Science,<\/em>&nbsp;<em>48<\/em>(4), 375-381. doi:<a href=\"https:\/\/doi.org\/10.4038\/cjs.v48i4.7679\" target=\"_blank\" rel=\"noreferrer noopener\">10.4038\/cjs.v48i4.7679<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"<p>by\u00a0Malaka Rodrigo\u00a0 Courtesy Mongabay.com A new type of forest ecology has been discovered from the ancient kingdom of Polonnaruwa in north-central Sri Lanka, centered around the irrigation canals abandoned there more than 700 years ago. The unique new forest type closely resembles the riverine forests that are found alongside rivers and other bodies of water, [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":true,"template":"","format":"standard","meta":{"footnotes":""},"categories":[160],"tags":[],"class_list":["post-103821","post","type-post","status-publish","format-standard","hentry","category-agriculture"],"_links":{"self":[{"href":"https:\/\/www.lankaweb.com\/news\/items\/wp-json\/wp\/v2\/posts\/103821","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.lankaweb.com\/news\/items\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.lankaweb.com\/news\/items\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.lankaweb.com\/news\/items\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.lankaweb.com\/news\/items\/wp-json\/wp\/v2\/comments?post=103821"}],"version-history":[{"count":0,"href":"https:\/\/www.lankaweb.com\/news\/items\/wp-json\/wp\/v2\/posts\/103821\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.lankaweb.com\/news\/items\/wp-json\/wp\/v2\/media?parent=103821"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.lankaweb.com\/news\/items\/wp-json\/wp\/v2\/categories?post=103821"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.lankaweb.com\/news\/items\/wp-json\/wp\/v2\/tags?post=103821"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}