engleski

First five years of digitisation of ZA and ZAHO collections (Croatia) – What did we learn?

With over 200.000 sheets, ZA is the oldest and the largest herbarium collection in Croatia, while the ZAHO stores as many as 78.000 sheets. Digitisation was initiated in 2015 resulting in 11.5 % of digitised sheets so far. Based on 3.721 sheets analysed, we determined specific temporal biases with different peak collections, e.g. orchids from 1870’s to 1910’s, aquatic plants in 1910’s, 1960’s and 2010’s, fagetal species from 1900 to 1950, and invasive flora from 1960 to 1970 and after 2010. Moreover, the average age of those collections is 90 years. Disproportionally large percentage of specimens collected by very few individuals indicates the presence of collector biases too. The ZA keeps a dozen aquatic taxa as the only evidence of their presence in Croatia. As herbaria usually follow invasions from the first recorded colonizer onwards, we searched whether the collections hide data on the arrival of aliens in Croatia. The first record of 17 taxa occurred much earlier in herbaria than in literature, with gaps that sometimes counted more than 100 years. Based on the study of several common and easily recognizable fagetal taxa, we found that they are rarely collected and their representation in the collections is inversely proportional to their number and distribution in nature.

herbarium, Zagreb, digitisation, bias

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