News from IAB

The mission of the International Association of Bryologists (IAB), as a society, is to strengthen bryology by encouraging interactions among all persons interested in byophytes.

Tuesday, November 26, 2013

The forbidden fruits and their mossy cover

An orchard in Gloucestershire – sheep-grazed, 
with standard trees  Photo by R. Stevenson
In my tropical homeland, apples are a rare treat – most commonly imported during Christmas season. One of the most amazing experiences when visiting temperate countries is finding apple trees everywhere! It’s just like the mango trees in almost every backyard in the Panamanian countryside. Then there are the twisted bryophyte- and lichen-covered old apple trees that creep along the walls of friends’ gardens in Scotland.

Orchards are excellent habitats for epiphytic mosses, with unexpectedly high bryophyte diversity: up to 40 species within an orchard dating to the 1950’s in Norfolk, UK (Stevenson & Rowntree 2009).

This means that a recent upsurge in community orchards (e.g. by the river Tay at Dunkeld, on the site of Johnny Bruce’sTearoom; by the river Tyne at St Mary’s Pleasance in Haddington; and more recently at my daughter’s school in North Berwick) should be good news for bryophytes. The recent news of the creation of 18 new community orchards in Cairgorms National Park, Scottish highlands (see BBC report) containing apple, plum and pear trees, will bring great benefit to local communities but also to orchard-loving bryophytes.  

The news also chimed with a talk on the topic by Dr. Mari Whitelaw (University of Hertfordshire) that I attended at the September 2013 readings of the British Bryological Society. There is some nice research on bryophyte diversity in orchard habitats in England by OPAL and Natural England. A recent illustrated identification guide for orchard mosses in the East of England has also been published and is available from here. David Long mentioned a similar effort in the Scottish Borders as part of a bigger project 'A national orchard inventory for Scotland'. See the website

Some orchard bryophytes.  From left to right, 
        (top): Cryphaea heteromalla, Hypnum cupressiforme
(bottom): Orthotrichum striatum, O. pulchellum. 

Partly prompted by the designation of orchards as UK Biodiversity Action Plan (BAP) habitats, Stevenson & Rowntree (2009) produced an interesting article on East Anglian (East England) orchards. Orchards have been classified as traditional (sheep-grazed) and commercial (high input and high use of pesticides), but according to the authors this is an oversimplified designation for East Anglian orchards. A key finding of their study is that plums make poor hosts for epiphytic bryophytes while apples are better. Also, species diversity seems to depend on the type of apple cultivar, the time of establishment and the management of the orchard. The authors paved the way for further in-depth research by Dr. Whitelaw on the biotic and abiotic factors affecting spatial and temporal distribution of bryophytes in orchards, essential to further establish conservation and management plants to protect this rich and unusual bryophyte habitat.
Thanks to Robin Stevenson for pictures, Laura Forrest and Mari Whitelaw for comments and sending important links.

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