Phylogenetic studies have shown the need for a revised circumscription of generic boundaries in the jelly lichens(Collemataceae).Using a four-marker dataset from a recently published phylogeny of Collemataceae,we test...Phylogenetic studies have shown the need for a revised circumscription of generic boundaries in the jelly lichens(Collemataceae).Using a four-marker dataset from a recently published phylogeny of Collemataceae,we tested the monophyly of ten morphologically well-characterized groups.To achieve this,we performed Bayesian and maximum likelihood analyses.The monophyly of the ten morphological groups was confirmed.In order to reconcile molecular and morphological data into a formal classification,we here propose new generic delimitations in Collemataceae.Collema and Leptogium are re-circumscribed and six old generic names are resurrected to accommodate the Collema Crispum-group(Blennothallia),the Collema Tenax-group(Enchylium),the Collema Cristatum-group(Lathagrium),the Collema Occultatum-group(Rostania),the former small Leptogium species(Scytinium),and Leptogium diffractum(Pseudoleptogium).In addition,two new genera are described to accommodate Collema multipartitum(Callome)and the Collema Italicum-group(Paracollema).The presence/absence of a eucortex,which was earlier used as the cardinal character to define genera in the family,is still useful,but only in combination with other traits such as thallus habit(size),lobe size,ascospore characteristics,thallus anatomical structure,and habitat preference.A key to the genera is provided.Lectotypes are designated for Collema marginale Hoffm.,Synechoblastus nigrescens(Huds.)Trevis.,Eucollema(Cromb.)Horw.,Collema section Enchylium Ach.,Collema section Lathagrium Ach.,Collema sect.Mallotium Ach.,Collema section Scytinium Ach.,Collemodium Nyl.ex Lamy,and Homodium Nyl.ex Olivier.展开更多
High-latitude terrestrial ecosystems face the triple threats of climate warming,increased exposure to UV arising from polar ozone depletion,and deforestation.Lichen communities of southernmost Chile are recognized for...High-latitude terrestrial ecosystems face the triple threats of climate warming,increased exposure to UV arising from polar ozone depletion,and deforestation.Lichen communities of southernmost Chile are recognized for their high diversity,which includes nitrogen-fixing cyanolichens.Such lichens are common on forest trees,contribute nitrogen to forests,and are sensitive to exposure following deforestation(widespread in this region).In a pilot study of exposure effects on tree lichens,using nondestructive imaging methods,we compared lichen communities on trunks of isolated vs.forest tree trunks of southern Chilean beech(Nothofagus dombeyi,Nothofagaceae).We chose trees of similar diameter and trunk lean angle in conserved forest and nearby logged meadow on Navarino Island,XII Region Magallanes and Chilean Antarctica,Chile,within the annual southern ozone hole.Ninety-five percent of cyanolichen records,including Nephroma antarcticum,and 66%of records for other foliose lichens were from the forest,whereas pendulous usneoid lichens dominated N.dombeyi bark at the meadow site.Limitation of cyanolichen growth on isolated trees could affect ecosystem function in this poorly studied habitat.Possible factors contributing to strong community differences were increased light intensity,UV radiation,and wind stress,plus limited ability of lichens to colonize isolated trees in the logged meadow.UV radiation was likely an important stressor for some lichen species but not others.We recommend more extensive monitoring to pinpoint causes of differing lichen communities,and we encourage better protection of bark-dwelling lichens in southern hemisphere regions facing multiple threats.展开更多
基金This research was generously supported by the Swedish Research Council grants VR 621-2009-5372 and VR 621-2012-3990by a postdoctoral grant from the Spanish Ministry of Education and Science(EDU3495/2010)。
文摘Phylogenetic studies have shown the need for a revised circumscription of generic boundaries in the jelly lichens(Collemataceae).Using a four-marker dataset from a recently published phylogeny of Collemataceae,we tested the monophyly of ten morphologically well-characterized groups.To achieve this,we performed Bayesian and maximum likelihood analyses.The monophyly of the ten morphological groups was confirmed.In order to reconcile molecular and morphological data into a formal classification,we here propose new generic delimitations in Collemataceae.Collema and Leptogium are re-circumscribed and six old generic names are resurrected to accommodate the Collema Crispum-group(Blennothallia),the Collema Tenax-group(Enchylium),the Collema Cristatum-group(Lathagrium),the Collema Occultatum-group(Rostania),the former small Leptogium species(Scytinium),and Leptogium diffractum(Pseudoleptogium).In addition,two new genera are described to accommodate Collema multipartitum(Callome)and the Collema Italicum-group(Paracollema).The presence/absence of a eucortex,which was earlier used as the cardinal character to define genera in the family,is still useful,but only in combination with other traits such as thallus habit(size),lobe size,ascospore characteristics,thallus anatomical structure,and habitat preference.A key to the genera is provided.Lectotypes are designated for Collema marginale Hoffm.,Synechoblastus nigrescens(Huds.)Trevis.,Eucollema(Cromb.)Horw.,Collema section Enchylium Ach.,Collema section Lathagrium Ach.,Collema sect.Mallotium Ach.,Collema section Scytinium Ach.,Collemodium Nyl.ex Lamy,and Homodium Nyl.ex Olivier.
文摘High-latitude terrestrial ecosystems face the triple threats of climate warming,increased exposure to UV arising from polar ozone depletion,and deforestation.Lichen communities of southernmost Chile are recognized for their high diversity,which includes nitrogen-fixing cyanolichens.Such lichens are common on forest trees,contribute nitrogen to forests,and are sensitive to exposure following deforestation(widespread in this region).In a pilot study of exposure effects on tree lichens,using nondestructive imaging methods,we compared lichen communities on trunks of isolated vs.forest tree trunks of southern Chilean beech(Nothofagus dombeyi,Nothofagaceae).We chose trees of similar diameter and trunk lean angle in conserved forest and nearby logged meadow on Navarino Island,XII Region Magallanes and Chilean Antarctica,Chile,within the annual southern ozone hole.Ninety-five percent of cyanolichen records,including Nephroma antarcticum,and 66%of records for other foliose lichens were from the forest,whereas pendulous usneoid lichens dominated N.dombeyi bark at the meadow site.Limitation of cyanolichen growth on isolated trees could affect ecosystem function in this poorly studied habitat.Possible factors contributing to strong community differences were increased light intensity,UV radiation,and wind stress,plus limited ability of lichens to colonize isolated trees in the logged meadow.UV radiation was likely an important stressor for some lichen species but not others.We recommend more extensive monitoring to pinpoint causes of differing lichen communities,and we encourage better protection of bark-dwelling lichens in southern hemisphere regions facing multiple threats.
