Search

Herbarium collections shape our understanding of the world’s flora and are crucial for addressing global change and biodiversity conservation. The formation of such natural history collections, however, are not free from sociopolitical issues of immediate relevance. Despite increasing efforts addressing issues of representation and colonialism in natural history collections, herbaria have received comparatively less attention. While it has been noted that the majority of plant specimens are housed in the global North, the extent of this disparity has not been rigorously quantified to date. Here, by analyzing over 85 million specimen records and surveying herbaria across the globe, we assess the colonial legacy of botanical collections and how we may move towards a more inclusive future. We demonstrate that colonial exploitation has contributed to an inverse relationship between where plant biodiversity exists in nature and where it is housed in herbaria. Such disparities persist in herbaria across physical and digital realms despite overt colonialism having ended over half a century ago, suggesting ongoing digitization and decolonization efforts have yet to alleviate colonial-era discrepancies. We emphasize the need for acknowledging the inconvenient history of herbarium collections and the implementation of a more equitable, global paradigm for their collection, curation, and use., bioRxiv

The report summarizes results from a cooperation among all the Nordic countries during the period 2015 – 2019 (two projects). The work has focused on the conservation of Crop Wild Relatives (CWR), i.e. wild plant species closely related to crops. They are of special importance to humanity since traits of potential value for food security and climate change adaptation can be transferred from CWR into crops. The projects represent the first joint action on the Nordic level regarding in situ conservation of CWR. Substantial progress has been made regarding CWR conservation planning, including development of a Nordic CWR checklist and identification of suitable sites for CWR conservation. A set of recommended future actions was developed, with the most important one being initiation of active in situ conservation of CWR in all Nordic countries.

The report summarizes results from a cooperation among all the Nordic countries during the period 2015 – 2019 (two projects). The work has focused on the conservation of Crop Wild Relatives (CWR), i.e. wild plant species closely related to crops. They are of special importance to humanity since traits of potential value for food security and climate change adaptation can be transferred from CWR into crops. The projects represent the first joint action on the Nordic level regarding in situ conservation of CWR. Substantial progress has been made regarding CWR conservation planning, including development of a Nordic CWR checklist and identification of suitable sites for CWR conservation. A set of recommended future actions was developed, with the most important one being initiation of active in situ conservation of CWR in all Nordic countries.

Global climate change will make the current habitat of many species unfavourable. It can also cause species suitable areas to shift or disappear. Under rapid climate change many species will not be able to adapt or disperse fast enough. Therefore, human-mediated dispersal of species has been proposed as a conservation method for mitigating the negative effects of climate change on biodiversity. In scientific discussions on the method, several different terms and definitions have been used. Such inconsistent use of terminology can lead to misunderstandings and to conflicting studies and evaluations of the method. In this thesis, assisted migration (AM) is suggested as the preferred term for the idea of translocating species threatened by climate change, and a concise definition that distinguishes it from other translocation practices is proposed. Should AM be accepted as a conservation tool, there is a demand for a readily applicable, rapid, and effective way of evaluating the species-specific benefit of AM. This thesis presents a method for estimating the need and potential of AM from predictions of changes in the range of species. The method is applied to several plant species and this thesis thus provides on of the first data-based estimations of the need to apply AM as a conservation strategy under different scenarios of climate change. The results indicate that the need and potential of AM for these species increases substantially with the strength of climate change and the temporal extent of climate change projections. Furthermore, this thesis suggests ways to deal with uncertainties in the process of obtaining range change predictions through species distribution models. Conventional assumptions concerning local adaptation within species, according to which species are treated as a single entity, may lead to erroneous predictions when applying species distribution models. Here, the magnitude of error in conservation guidance that can be introduced through opposing assumptions concerning local adaptation is explored. It is found that the assumption of local adaptation and, therefore, separate modelling of populations can provide different and more precautionary outcomes compared to the assumption of no local adaptation and, hence, modelling the species as a whole. To obtain insight into the presence of intraspecific local adaptation to climatic conditions, a translocation trial of two geographically separated populations of the same plant species was initiated. The preliminary results presented here indicate that one of the studied populations is less adapted to conditions in its home environment while the other population exhibits stronger local adaptation. Knowledge of this kind provided by experimental studies should be reflected in studies using species distribution modelling to reduce uncertainty in predictions and threat estimates based on the models. This thesis concludes that predictive tools such as species distribution models hold great potential in providing rough estimates of future trajectories for conservation of biodiversity and could provide a useful scientific basis for policy decisions. However, more in-depth knowledge, which can be gained through experimental approaches, is needed to detail how individual species and populations may respond to altered conditions in their environment and which conservation method is the most relevant. Den globala klimatförändringen kommer att förändra många arters habitat. Arternas nutida levnadsområden kan bli ofördelaktiga då lämpliga förhållanden förflyttas eller försvinner på grund av klimatförändringen. Många arter kommer inte att kunna flytta i takt med den snabba klimatförändringen. Därför har man föreslagit en ny artsskyddsmetod för att minska klimatförändringens negativa effekter på biodiversiteten: att människan skulle hjälpa arter migrera till nya lämpliga områden. I den vetenskapliga diskussionen angående metoden har flera olika termer och definitioner använts. En dylik inkonsekvent tillämpning av terminologi kan leda till missförstånd samt oförenliga undersökningar och utvärderingar av metoden. I denna avhandling föreslås assisterad migration (AM; eng. assisted migration) som den rekommenderade termen för att beskriva idén om att flytta arter vilka hotas av klimatförändringen. En koncis definition som åtskiljer metoden från närbesläktade begrepp presenteras. Ifall AM skulle accepteras som en artskyddsmetod finns det ett behov av applicerbara och effektiva sätt av utvärdera fördelar av metoden för enskilda arter. Denna avhandling presenterar en metod för av utvärdera behovet och potentialen av AM utgående från förutsägningar angående förändringar i utbredningsområden. Metoden appliceras på flera växtarter och denna avhandling utgör därmed en av de första databaserade bedömningarna av behovet att applicera AM som en artskyddsmetod under olika scenarier av klimatförändring. För de undersökta arterna påvisar resultaten att behovet och potentialen av AM ökar märkbart med en förstärkning och förlängning av klimatförändringen. Vidare föreslår denna avhandling olika sätt att behandla osäkerheter i processen för att erhålla förutsägningar med hjälp av utbredningsmodeller. Konventionella antaganden angående anpassning inom arten, enligt vilken man behandlar arten som en enhetlig helhet, kan leda till felaktiga slutsatser eftersom populationer inom arten kan vara anpassade till lokala förhållanden. I avhandlingen utforskas omfattningen av felbedömningar inom artskydd som kan introduceras via motsatta antaganden angående lokal anpassning. Resultaten indikerar att fristående modeller av populationer enligt antagandet att populationer är anpassade till lokala förhållanden kan leda till annorlunda och mer aktsamma bedömningar av framtida utbredningsområden jämfört med den konventionella metoden att behandla arten som en helhet. För att belysa förekomsten av anpassning till klimatiska förhållanden inom en art anlades ett transplantationsförsök var två geografiskt separerade populationer av samma art odlades i olika klimatförhållanden. De preliminära resultaten som presenteras här påvisar att en av de undersökta populationerna är relativt svagt anpassad till sina hemförhållanden medan den andra populationen uppvisar starkare lokal anpassning. Dylik information, vilken kan uppnås via experiment, borde återspeglas i studier var utbredningsmodeller används för att förminska osäkerhet i förutsägelserna och på dem baserade hotbedömningar. I denna avhandling dras slutsatsen att metoder för att åstadkomma förutsägningar, så som utbredningsmodeller, har hög potential för att ge grova estimat angående möjliga framtida utkomster för biodiversitetsskydd och kan utgöra en användbar vetenskaplig bas för beslutsfattandet. Mer djupgående information, som kan uppnås via experimentella tillvägagångssätt, behövs ändå för att specificera hur individuella arter och populationer kan komma att reagera på miljöförändringar och vilken artskyddsmetod som då är mest relevant.

Plant invasions cause a serious threat to native biodiversity. Agricultural habitats are highly disturbed and often invaded by the alien plant species. Generally, the success of a plant invader depends on the abiotic (e.g. climate, habitat properties) and biotic factors (e.g. the characteristics of the invader and interaction with the resident species). In this thesis, I determined the invasion level of alien plant species in Finnish agricultural habitats. In addition, I assessed the environmental conditions and species characteristics affecting plant invasions, and the alien species impact on native species richness and diversity. The invasion level of alien plant species varied between different types of semi-natural agricultural habitats, geographical regions and study years. Generally, more frequently disturbed and more intensively managed habitats (e.g. field and road verges) were more often invaded by alien plants than infrequently disturbed and managed habitats (e.g. grassland). However, the effect of disturbance regime tended to depend on residence time of the alien plant species, and vary among the alien plant species. The invasion level decreased towards north with decreasing temperature and increased towards east with increasing continentality. The geographical trends may be explained by climate, migration history and land-use intensity. In addition, alien plant species diversity increased with higher native plant species diversity. Thus, the results suggest that species interactions, especially competition, with resident plant species do not limit plant invasions in semi-natural agricultural habitats. The positive relationship between native and alien species may be caused by both suitable environmental conditions and spatial heterogeneity in environmental conditions partly created by disturbance of agricultural habitats. The species traits of alien plant species are habitat-specific and strongly related environmental conditions. I did not find evidence that alien plants species cause a severe threat to native plant diversity in Finnish semi-natural habitats. The most harmful invasive plant species are still rare in Finnish agricultural landscape. In the future, the pressure of establishment and spread of alien species can be assumed to increase. Thus, regular monitoring is needed for early detection of new species and detection of the changes in the distribution and the spread of established alien species. The fact that plant invasions are species-specific and depended on environmental characteristics calls for habitat- and species-specific studies on the impacts of alien species and on the determinants of plant invasion at multiple spatial scales. Vieraslajit voivat aiheuttaa vakavan uhan alkuperäisen lajiston monimuotoisuudelle. Maatalous on luonut vieraskasvilajeille suotuisia elinympäristöjä. Vieraskasvilajien menestymiseen vaikuttavat sekä lajin että kasvupaikan ominaisuudet, kuten ilmasto ja elinympäristön ominaisuudet. Tässä väitöskirjatutkimuksessa selvitettiin vieraskasvilajien esiintymistä sekä niiden runsauteen vaikuttavia ympäristötekijöitä puoliluonnontilaisissa maatalousympäristöissä. Lisäksi tutkittiin vieraskasvilajien vaikutusta alkuperäisten lajien runsauteen ja monimuotoisuuteen. Vieraskasvilajien runsaus ja lajimäärä vaihtelivat riippuen elinympäristötyypistä, maantieteellisestä alueesta ja tutkimusvuodesta. Vieraskasvilajeja esiintyi enemmän voimakkaimmin häirityissä ja hoidetuissa elinympäristöissä, kuten pellon- ja tienpientareilla, kuin satunnaisesti häirityissä ja hoidetuissa elinympäristöissä, kuten niityillä. Häiriöiden vaikutus riippui kuitenkin siitä, milloin vieraslaji oli saapunut Suomeen. Myöhemmin saapuneiden vieraslajien lajimäärä kasvoi paljaan maan alan kasvaessa, kun taas aiemmin saapuneiden muinaistulokkaiden lajimäärää lisäsi myös niitto. Vieraskasvien runsaus ja lajimäärä kasvoivat kohti itää ja pienenivät siirryttäessä kohti pohjoista lämpötilan ja kasvukauden pituuden laskiessa. Lajirikkaat kasviyhteisöt eivät rajoittaneet vieraskasvien esiintymistä, vaan niiden monimuotoisuus kasvoi alkuperäisten lajien lajimäärän kasvaessa. Tämä viittaa siihen, että molemmat lajiryhmät hyötyivät samoista suotuisista ympäristöolosuhteista. Menestyvien vieraslajien ominaisuudet olivat lajikohtaisia ja ympäristöolosuhteista riippuvaisia. Niinpä onkin mahdotonta määritellä vieraskasvilajien menestyksen taustalla olevia lajipiirteitä, jotka kattaisivat kaikki ympäristöolosuhteet. Tutkimustulosten perusteella vieraskasvilajit eivät aiheuta vakavaa uhkaa alkuperäisten kasvilajien monimuotoisuudelle suomalaisissa puoliluonnontilaisissa maatalousympäristöissä. Haitallisimmat vieraskasvilajit olivat edelleen harvinaisia maatalousmaisemassa. Tulevaisuudessa riski vieraskasvilajien vakiintumiselle ja leviämiselle voi kuitenkin kasvaa. Näin ollen säännöllinen seuranta on tarpeen, jotta niin uudet vieraskasvilajit kuin myös muutokset jo vakiintuneiden lajien levinneisyydessä ja runsaudessa voitaisiin havaita ajoissa. Koska vieraskasvilajien menestyminen riippuu kyseessä olevasta lajista sekä ympäristön ominaisuuksista, ei ole olemassa yhtä yksinkertaista ratkaisua vieraslajien hallitsemiseksi. Näin ollen arviot vieraslajien haitallisuudesta sekä niiden torjunnasta pitäisi tehdä lajikohtaisesti huomioiden lajin ominaispiirteet ja ympäristön ominaisuudet.