On the complexity of dealing with introduced plants as cultural heritage : a historical multidisciplinary study of plants introduced to Norway from 1750 to 1900, exemplified with Abies alba Mill. (European silver fir) as a case species

Abstract

As the independent nation of Norway was at its infancy in 1814, so was also an important change in Norwegian garden culture. Norway was about to experience a significant boom of plant introductions for ornamental use, which slowly began as early as in the mid-1700s. A naturalistic garden design used to dominate, which involved particularly imported plants. As a contrast to this passion for introduced plants in the past, these plants are at present increasingly approached as problematic objects. All plants introduced in the year 1800 or later are since 2012 categorised as alien species. Considering that plants can represent both cultural heritage and alien species, which potentially can harm Norwegian nature and biodiversity, it is a matter that concerns different disciplines and management interests.

This thesis is a three-disciplinary work, involving methods from the disciplines history, botany and genetics. The aim was to approach plants introduced in the 1800s by combining methods from these different fields. Abies alba Mill., commonly known as European silver fir, was selected as a case species to represent this category of introduced plants and, in particular, of blacklisted plant species in Norway.

Paper I examines how introduced plants were described and reflected on in Norwegian literature from 1750 to 1900. Historical literary sources were accessed from archives and historical library collections in Oslo, Ås and London (UK). The texts were analysed with emphasis on middleclass people’s (i.e. academics, civil servants, merchants and the clergy) perception of introduced plants and how their attitudes changed from 1750 to 1900. Positive attitudes towards introduced plants increased significantly in the investigated period. After the century turn 1800, the middleclass played an important role regarding the use of ornamental plants. As the establishment of plant nurseries increased in the mid-1800s, new plant assortments became more accessible for the general public. This led to a garden culture marked by a diversity of exciting and new plants, which also illustrates the predominantly positive views on introduced plants after the 1850s. Regarding the term exotic plants, such plants appeared as something positive when used to describe rare, unusual and exciting plants, often new to science. In contrast, introduced plants that are presently addressed as alien plants in Norway are associated with something negative, which seemingly contributes to negative attitudes towards introduced plants in general.

With Abies alba as a case species, paper II deals with the management of a blacklisted heritage tree in a protected landscape. This was approached by combining literary studies and fieldwork in Austråttlunden, a protected landscape situated in central coastal Norway. The literary approach involved studies about Austråttlunden’s history, the introduction of Abies alba, its management during the past 40 years and people’s experience of and relation to the area. Fieldwork, with a focus on invasiveness, involved an inventory of Abies alba seedlings with GPS along transects to map its spreading in the area and the recording of some ecological parameters and growing conditions. As an introduced and blacklisted plant species, Abies alba constitutes both cultural heritage and a threat to ecological values, represented by native plants species and sensitive habitats. The study shows that Abies alba spreads relatively slowly and that most seedlings establish within 30 m of the parent in half-shade positions. Continued maintenance such as vegetation clearing and grazing prevents and limits the spread of Abies alba. This kind of maintenance is also required to conserve a protected landscape with a certain cultural historical character. Abies alba has received more attention as an invasive species, although it is part of the area’s cultural historical identity. At present, the management is mainly the responsibility of ecological conservationists, which is why natural values have been prioritised. To equally address natural, cultural and historical values, collaborations between professionals from different disciplines are required. This would allow to safeguard not only native plants species and habitats dependent on the cultural landscape, but also a blacklisted heritage tree.

The scope of paper III was to generate new knowledge about plant introduction history by involving genetics. With Abies alba as a case species, this issue was approached through a combination of historical literary studies, fieldwork and laboratory work. Literary sources provided information about the introduction of Abies alba in the late 1800s and indicated that the same people had been involved in some planting projects in central coastal Norway. In cases where historical sources were lacking, the goal was to use genetic data as a complement to fill knowledge gaps. This study included seven localities in central coastal Norway and one locality in southern Norway. The DNA was extracted from fresh Abies alba needles collected in the field. High-molecular weight DNA samples were prepared for sequencing by following the ddRAD protocol by Peterson et al. (2012). The full genomic sequenced data were processed using STACKS v1.18 to detect SNPs. Relatedness and population structure were analysed using the STRUCTURE software version 2.3.4. For the phylogenetic analysis, we used BIONJ, and principal coordinate analysis was performed with the software package GenAlEx version 6.5. The genetic relatedness supported historical sources regarding the connexion between three of the localities. The results also enabled predictions of how people might have accessed and shared Abies alba between the other localities. The study has shown that genetics, in combination with historical sources, is a valuable tool to uncover new pieces of the whole process of plant introduction.

The issue of introduced plants is a complex research object as it concerns many different fields. By looking back on the period from 1750 to 1900, the primary step involved history in order to learn about the background of plant introduction in this period and how the new plants were perceived. Further, the attention was drawn towards the challenge this category of introduced plants constitutes in a management context, with Abies alba as an example. With introduction history as a leading thread, genetics was involved as a third discipline to help generate new knowledge about the introduction and distribution of Abies alba. Abies alba functioned as a bridge between the past and the present and connected the three disciplines history, botany and genetics.

The thesis particularly contributes to the societal debate on the management of introduced species and is a step forward to equally address natural and cultural values. Overall, this work contributes to initiate dialogues and interdisciplinary collaborations between professionals.

Mange prydplanter i Norge har en introduksjonshistorie som startet samtidig som den norske grunnloven ble etablert i 1814. På denne tiden startet også en ny epoke i norsk hagekultur. En ny trend og hunger etter nye planteslag begynte sakte allerede i midten av det attende århundre, der import og bruk av planter var en betydelig del. Den gangen hadde norske hager en naturalistisk stil med innslag fra Europa. Nye planteslag fra utlandet kunne tilby mer variasjon og mangfold enn det som fantes i norsk natur. Som en kontrast til etterspørselen på introduserte planter i det attende og nittende århundrene, er disse plantene mottatt annerledes i dag. Alle plantearter introdusert år 1800 eller senere er siden 2012 kategorisert som fremmede arter. Dette berører ulike disipliner, og forvaltningsinteressen ettersom disse plantene representerer både kulturarv og fremmede arter, med potensiell evne for å bidra til skade på natur og biologisk mangfold i Norge. Denne avhandling er et empirisk bidrag til tverrfaglig forskning på innførte planter. Målet er å se nærmere på planter introdusert i Norge på 1800-tallet ved å kombinere metoder fra disiplinene historie, botanikk, og genetikk. Abies alba Mill. (vanlig edelgran) ble valgt ut som case-plante, for å representere planter introdusert på 1800-tallet, i tillegg til svartlistede planter.