Ilmastonmuutos ja vieraslajien leviäminen Suomeen – Tutkimustiedon synteesi ja suurilmastollinen vertailu

Vieraslajit ovat maailmanlaajuinen ympäristöongelma, joilla on huomattavia ekologisia, taloudellisia ja terveydellisiä haittavaikutuksia. Aggressiivisesti leviävät haitalliset vieraslajit ovat elinympäristöjen häviämisen jälkeen toiseksi suurin syy luonnon monimuotoisuuden vähenemiseen. Ilmastonmuutos tulee voimistamaan useilla alueilla vieraslajien leviämistä, sekä vahvistamaan niiden kykyä muodostaa elinvoimaisia populaatioita luonnossa ja aiheuttaa merkittäviä haittoja alkuperäiselle lajistolle. Tätä kehitystä voimistaa kasvava kansainvälinen kauppa ja liikenne. Tässä työssä selvitetään ilmastonmuutoksen ja vieraslajien yhteyksiä sekä ilmastonmuutoksen vaikutuksia Suomen vieraslajien tilanteeseen kolmesta eri näkökulmasta; (1) Laaja kirjallisuusselvitys kokoaa yhteen tuoreen tiedon Euroopan vieraslajeista. Erityisesti tarkastellaan mihin seikkoihin vieraslajien voimakas leviäminen perustuu, minkälaisista lajeista tulee haitallisesti luonnonympäristöihin leviäviä vieraslajeja ja miten ilmastonmuutos vaikuttaa vieraslajien leviämiseen ja niiden torjuntaan; (2) Euroopan ilmastoskenaarioiden perusteella arvioidaan sitä, miltä alueilta uusia vieraslajeja voi levitä Suomeen ilmastonmuutoksen myötä ja mitkä näistä lajeista ovat haittavaikutuksiltaan merkittävimpiä; (3) Globaalien suurilmastollisten vertailujen avulla selvitetään mitkä maantieteelliset alueet ovat kaikkein todennäköisimpiä haitallisten vieraslajien lähtöalueita eli miltä alueilta voi nykyään ja tulevaisuudessa levitä uusia Suomen luonnossa menestyviä vieraslajeja

Vesikasvit Suomen järvien tilan ilmentäjinä. Ekologisen tilaluokittelun kehittäminen

Vesikasvillisuus on yksi järvien ekologisen tilan arvioinnissa käytettävistä eliöryhmistä. Vaikka Suomessa  on tehty lukuisia vesikasvitutkimuksia, niiden tuloksia ei ole aiemmin laajassa mitassa käytetty järvien ekologisen tilan luokittelussa. Työn tavoitteena on arvioida järvien vesikasvillisuuteen perustuvia ekologisen laadun muuttujia suhteessa vuoden 2002 järvityypittelyehdotukseen. Lisäksi työssä on tarkasteltu vertailujärvien lajimäärän vaihtelua Etelä- ja Pohjois-Suomen välillä ja sen merkitystä ekologisen tilan luokittelussa sekä selvitetty järvityyppien erottumista toisistaan tyypeille luontaisten vesi- ja rantakasviyhteisöjen ominaisuuksien perusteella. Vertailujärvien keskimääräinen kokonaislajimäärä oli pienin tunturijärvissä ja suurin suurissa, kohtalaisen humuspitoisissa järvissä sekä luontaisesti runsasravinteisissa järvissä. Kuormitetuissa järvissä vesi- ja rantakasvien kokonaislajimäärä ja hydrofyyttien lajimäärä on yleensä suurempi kuin vertailujärvissä. Vesi- ja rantakasvien lajimäärä on alhaisempi Pohjois-Suomen vertailujärvissä kuin Etelä-Suomen vertailujärvissä. Näyttäisikin perustellulta käsitellä Pohjois-Suomen järviä erikseen ekologisen tilan arvioinnissa. Elomuotojen runsausosuudet poikkesivat toisistaan eri järvityyppien vertailuolojen välillä, mikä viittaa järvityyppien välisiin luontaisiin eroihin vesi- ja rantakasvillisuuden koostumuksessa. Kun tarkastellaan ekologisen tilan luokittelussa mukana olleita neljää järvityyppiä, lajimuuttujista sopivimpia ekologisten laatusuhteiden laskemiseen olivat tyyppilajien suhteellinen osuus, prosenttinen mallinkaltaisuus ja lajimäärä. Kasvillisuuden runsauteen perustuvista muuttujista soveltuvimpia ekologisten laatusuhteiden laskemiseen olivat meso-eutrofia -lajien ja oligotrofia -lajien runsausosuus sekä pohjalehtisten runsausosuus

Quantifying the climate exposure of priority habitat constrained to specific environmental conditions : Boreal aapa mires

Climate velocity is an increasingly used metric to detect habitats, locations and regions which are exposed to high rates of climate change and displacement. In general, velocities are measured based on the assumption that future climatically similar locations can occur anywhere in the study landscape. However, this assumption can provide a biased basis for habitats which are constrained to specific environmental conditions. For such habitats, a set of selected suitable locations may provide ecologically more realistic velocity measures. Here, we focus on one environmentally constrained habitat, aapa mires, which are peat-accumulating EU Habitats Directive pri-ority habitats, whose ecological conditions and biodiversity values may be jeopardised by climate change. We assess the climate exposure of aapa mires in Finland by developing velocity metrics separately for the whole >= 10 ha aapa mire complexes ('aapa mires') and their wettest flark-dominated parts ('flark fens'). Velocity metrics were developed for six bioclimatic variables (growing degree days (GDD5), mean January and July temperatures, annual precipitation, and May and July water balance, based on climate data for 1981-2010 and for 2040-2069 as derived from global climate models for two Representative Concentration Pathways (RCP4.5 and RCP8.5). For the six variables, velocities were calculated based on the distance between climatically similar present-day and nearest future mire, divided by the number of years between the two periods, and by excluding the unsuitable matrix. Both aapa mires and flark fens showed high exposure (>5 km/year) to changes in January temperature, and often also considerably high velocities for GDD5 and July temperatures. The flark fens showed significantly higher climate velocities than the aapa mires and had a smaller amount of corresponding habitat in their sur-roundings. Thus, many of the studied mires, particularly the flark fens, are likely to face increased risks of exposure due to changes in winter and summer temperatures. Moreover, considerable changes in precipitation -related conditions may occur at the southern margin of the aapa mire zone. Our results show that specifically tailored climate velocity metrics can provide a useful quantitative tool to inform conservation and management decisions to support the ecosystem sustainability of this EU Habitats Directive biotope and targeting restoration towards the most vulnerable aapa mires.Peer reviewe

Impacts of land cover data selection and trait parameterisation on dynamic modelling of species' range expansion

Peer reviewedPublisher PD

Modeling of Dead Wood Potential Based on Tree Stand Data

Here we present a framework for identifying areas with high dead wood potential (DWP) for conservation planning needs. The amount and quality of dead wood and dying trees are some of the most important factors for biodiversity in forests. As they are easy to recognize on site, it is widely used as a surrogate marker for ecological quality of forests. However, wall-to-wall information on dead wood is rarely available on a large scale as field data collection is expensive and local dead wood conditions change rapidly. Our method is based on the forest growth models in the Motti forest simulator, taking into account 168 combinations of tree species, site types, and vegetation zones as well as recommendations on forest management. Simulated estimates of stand-level dead wood volume and mean diameter at breast height were converted into DWP functions. The accuracy of the method was validated on two sites in southern and northeastern Finland, both consisting of managed and conserved boreal forests. Altogether, 203 field plots were measured for living and dead trees. Data on living trees were inserted into corresponding DWP functions and the resulting DWPs were compared to the measured dead wood volumes. Our results show that DWP modeling is an operable tool, yet the accuracy differs between areas. The DWP performs best in near-pristine southern forests known for their exceptionally good quality areas. In northeastern areas with a history of softer management, the differences between near-pristine and managed forests is not as clear. While accurate wall-to-wall dead wood inventory is not available, we recommend using DWP method together with other spatial datasets when assessing biodiversity values of forests

Combined threats of climate change and land use to boreal protected areas with red-listed forest species in Finland

Peer reviewe

Can Topographic Variation in Climate Buffer against Climate Change-Induced Population Declines in Northern Forest Birds?

Increased attention is being paid to the ecological drivers and conservation measures which could mitigate climate change-induced pressures for species survival, potentially helping populations to remain in their present-day locations longer. One important buffering mechanism against climate change may be provided by the heterogeneity in topography and consequent local climate conditions. However, the buffering capacity of this topoclimate has so far been insufficiently studied based on empirical survey data across multiple sites and species. Here, we studied whether the fine-grained air temperature variation of protected areas (PAs) affects the population changes of declining northern forest bird species. Importantly to our study, in PAs harmful land use, such as logging, is not allowed, enabling the detection of the effects of temperature buffering, even at relatively moderate levels of topographic variation. Our survey data from 129 PAs located in the boreal zone in Finland show that the density of northern forest species was higher in topographically heterogeneous PAs than in topographically more homogeneous PAs. Moreover, local temperature variation had a significant effect on the density change of northern forest birds from 1981–1999 to 2000–2017, indicating that change in bird density was generally smaller in PAs with higher topographic variation. Thus, we found a clear buffering effect stemming from the local temperature variation of PAs in the population trends of northern forest birds

Can Topographic Variation in Climate Buffer against Climate Change-Induced Population Declines in Northern Forest Birds?

Increased attention is being paid to the ecological drivers and conservation measures which could mitigate climate change-induced pressures for species survival, potentially helping populations to remain in their present-day locations longer. One important buffering mechanism against climate change may be provided by the heterogeneity in topography and consequent local climate conditions. However, the buffering capacity of this topoclimate has so far been insufficiently studied based on empirical survey data across multiple sites and species. Here, we studied whether the fine-grained air temperature variation of protected areas (PAs) affects the population changes of declining northern forest bird species. Importantly to our study, in PAs harmful land use, such as logging, is not allowed, enabling the detection of the effects of temperature buffering, even at relatively moderate levels of topographic variation. Our survey data from 129 PAs located in the boreal zone in Finland show that the density of northern forest species was higher in topographically heterogeneous PAs than in topographically more homogeneous PAs. Moreover, local temperature variation had a significant effect on the density change of northern forest birds from 1981–1999 to 2000–2017, indicating that change in bird density was generally smaller in PAs with higher topographic variation. Thus, we found a clear buffering effect stemming from the local temperature variation of PAs in the population trends of northern forest birds