Temporal changes in boreal vegetation under 70 years of conservation

Biodiversity conservation through protected areas (PAs) is often based on the idea that biodiversity is relatively static. This assumption is increasingly being challenged as species and communities shift their distributions in response to changing environmental conditions. Empirical evidence on the performance of PAs over decades is still sparse or lacking from several environments, although it is needed to understand species dynamics, support modelling of PA performance, assist PA management and ultimately, to achieve global biodiversity conservation goals. In 2021, we resurveyed vegetation of five boreal habitat types (heath forests, paludified forests, sun-exposed sites, mires and eulittoral sites) in Rokua National Park in Finland, where one of the conservation targets is to preserve the flora characteristic of the area. The study sites were originally surveyed in 1945-49, just before the National Park was established. Study sites have also remained free from the disturbances (forest fires and reindeer grazing) typical of boreal regions. We show that the compositional similarity of plant communities between habitat types has increased over time and is associated with the increase of forest species in several habitat types and the loss of many habitat-specific species. Drivers of change were most often linked to ongoing succession (understory closure) and changes in moisture conditions. Our results suggest that without natural disturbance or appropriate management efforts, the original conservation targets may be compromised over the decades. Our study demonstrates that resurvey of historical vegetation data can be effectively used to estimate long-term PA performance, helping to fill in missing temporal evidence.publishedVersio

Trait-based responses to land use and canopy dynamics modify long-term diversity changes in forest understories

Aim Land use is the foremost cause of global biodiversity decline, but species do not respond equally to land-use practices. Instead, it is suggested that responses vary with species traits, but long-term data on the trait-mediated effects of land use on communities are scarce. Here we study how forest understorey communities have been affected by two land-use practices during 4-5 decades, and whether changes in plant diversity are related to changes in functional composition. Location Finland. Time period 1968-2019. Major taxa studied Vascular plants. Methods We resurveyed 245 vegetation plots in boreal herb-rich forest understories, and used hierarchical Bayesian linear models to relate changes in diversity, species composition, average plant size, and leaf economic traits to reindeer abundance, forest management intensity, and changes in climate, canopy cover and composition. We also studied the relationship between species evenness and plant size across both space and time. Results Intensively managed forests decreased in species richness and had increased turnover, but management did not affect functional composition. Increased reindeer densities corresponded with increased leaf dry matter content, evenness and diversity, and decreased height and specific leaf area. Successional development in the canopy was associated with increased specific leaf area and decreased leaf dry matter content and height in the understorey over the study period. Effects of reindeer abundance and canopy density on diversity were partially mediated by vegetation height, which had a negative relationship with evenness across both space and time. Observed changes in climate had no discernible effect on any variable. Main conclusions Functional traits are useful in connecting vegetation changes to the mechanisms that drive them, and provide unique information compared to turnover and diversity metrics. These trait-dependent selection effects could inform which species benefit and which suffer from land-use changes and explain observed biodiversity changes under global change.Peer reviewe

Biologian kenttäopetus yliopistoissa: yhteistyöllä uuteen nousuun

Kenttäkurssit ovat keskeinen osa biologian ja lähitieteiden opetusta yliopistoissa. Luonnossa tapahtuva opetus kehittää sekä ymmärrystä tieteenalan teoreettisista perusteista että ammatillisia käytännön taitoja. Kenttäkursseilla omat havainnot muodostuvat oppimisen perustaksi muiden oppimistapojen rinnalla. Vaikka kenttäopetuksen tarpeellisuudesta ollaan yksimielisiä, kenttäkursseja uhkaavat yliopistojen rahoituksen väheneminen ja tutkimusasemaverkoston karsiminen. Tässä kirjoituksessa pohdimme, kuinka uhkista huolimatta kenttäopetuksen määrää, laatua ja kustannustehokkuutta voidaan lisätä yliopistojen ja niiden tutkimusasemien välisellä yhteistyöllä.</p

Decadal and centennial changes of boreal forest vegetation and soil microbial communities:natural and altered dynamics

Abstract Human actions are considered to cause a severe threat to boreal forest systems. Even though some influences are noticed to occur with a remarkable time-lag, long-term studies of this topic are still scarce and partly contradictory. The importance of above-ground and below-ground linkages has also only recently been emphasized. Yet, boreal forests have potential to be resistant and resilient to global change. Understanding the impacts of these pressures on various aspects of forest systems, has scientific and functional value. In this thesis, I have studied natural and altered long-term dynamics of forest understory vegetation (vascular plants, bryophytes and lichens) on nutritionally different boreal forests using resurvey data. I have also studied the development of understory vegetation and soil microbial communities (fungi and bacteria) on a long-term (ca 1500 yrs.) soil primary successional series on land uplift shores. All studied communities changed remarkably in time, partly naturally by succession, partly due to human influence. Interestingly, the development of vegetation and soil microbial communities was related to accumulation of organic matter instead of nutrients on our nutrient limited study system. In herb-rich forests, temporal changes led to increasing homogeneity in forest understorey communities. This study is among the first to show that reindeer grazing can regulate vegetation dynamics in boreal, herb-rich forests by reducing vegetation height and maintaining diversity. Forest management had surprisingly little influence on the understory vegetation of herb-rich and coniferous forests. Forest management reduced the accumulation of coarse woody debris. Importantly, forest management impacts were detectable long time after management, and thus appear as legacy effects in forest plant community structure and woody debris. The results of this thesis emphasize the value of long-term studies and involving above-ground and below-ground linkages. When using larger datasets, taking regional processes into account can be highly useful as can be the use of diverse response variables for detecting ecologically relevant changes of e.g. lighter forest management practices.Tiivistelmä Ihmistoiminnan on arvioitu heikentävän pohjoisia metsiä osan vaikutuksista ilmetessä pitkien aikojen kuluttua. Silti pitkäaikaistutkimusta aiheesta on vähän ja tulokset ovat osin ristiriitaisia. Maaperän ja kasvillisuuden vuorovaikutusten merkitystä metsien toimintaan on vasta alettu ymmärtää syvällisemmin. Toisaalta metsäkasvillisuuden on arvioitu sietävän muutoksia. Tiedolla globaalimuutoksen vaikutuksista metsäyhteisöjen ominaisuuksiin on merkittävää tieteellistä ja käytännön arvoa. Väitöskirjassani tutkin lehtojen ja kangasmetsien aluskasvillisuuden (putkilokasvit, sammalet ja jäkälät) luontaisia ja muuttuneita pitkän ajan kehityskulkuja uudelleenkartoitusaineistoilla. Tutkin myös kasvillisuuden ja maan mikrobiyhteisöjen (bakteerit ja sienet) kehitystä sukkessiosarjalla. Kaikki tutkimani yhteisöt muuttuivat ajassa ja osa muutoksista liittyi luontaiseen kehitykseen, osa ihmisvaikutukseen. Mikrobi- ja kasviyhteisöjen vuorovaikutteinen kehitys kytkeytyi ravinteiden sijaan orgaanisen aineen kertymiseen ravinnerajoitteisissa metsissä. Lehdoissa luontainen kehitys muutti aluskasvillisuuden yhteisöjä ja latvustoa kohti havupuuvaltaisempaa tilaa, mikä onkin yksi lehtoja uhkaava tekijä. Tämä on ensimmäisiä tutkimuksia, joka osoittaa porolaidunnuksen säätelevän kasviyhteisöjä boreaalisissa lehtometsissä ylläpitämällä monimuotoisuutta ja lehdoille tyypillistä lajikoostumusta pitämällä kasvillisuuden matalana. Metsätaloustoimien vaikutukset ilmenivät yllättävän vähän lehtojen ja havumetsien aluskasvillisuudessa. Lahopuun määrää metsätalous vähensi voimakkaasti. Tärkeä havainto oli, että metsänhoitotoimenpiteiden vaikutuksia ilmenee huomattavalla viipeellä. Väitöskirjani tulokset korostavat pitkäaikaistutkimuksen arvoa sekä maanpäällisten ja -alaisten prosessien huomioimista. Työni tulokset osoittavat, että suurilla aineistoilla alueellisten tekijöiden huomioimisesta voi olla hyötyjä samoin kuin monipuolisten ekologisten mittareiden käytöstä ekologisesti merkittävien muutosten havaitsemiseksi esimerkiksi tutkittaessa lievempien metsätaloustoimien vaikutuksia

Legacy effects of logging on boreal forest understorey vegetation communities in decadal time scales in northern Finland

Abstract We followed how forest thinning, repeated twice during a period of 93 years, altered understorey plant community composition, affected the succession of forest understorey vegetation and the accumulation of logs in the long-term. The study was carried out in northern Finland by resampling 20 permanent experimental plots, established after a wildfire in 1920. Understorey vegetation was inventoried in 1961, 1986 and 2013 with forest thinning treatments done in 1953 and 1987, using four and three different harvesting intensities, respectively. We found succession to override the effects of forest logging until the latest study period (2013). We observed negligible long-term effects of logging on understorey communities during the two mid-successional stages (1961, 1986), when the forest was 41 and 66 years old respectively. The impacts of logging on understorey vegetation were strongest in the latest successional stage (2013), the forest being at the age of 93 years. In the latest successional stage (2013) logged plots had less coarse woody debris than unlogged plots. Forest management thus influenced the key feature for forest biodiversity and potential habitats for endangered species. These findings are of major interest since the studies of long-term impacts of less intensive forest management practices are scarce. Our results suggest that in addition to possible immediate impacts, harvesting treatments have legacy effects (subtle or delayed inherited effects of forestry in the past) that influence the forest understorey vegetation community composition and the amount of coarse woody debris. This finding deserves special attention when planning of species conservation, multiple use of forests and sustainable forestry

Temporal changes in boreal vegetation under 70 years of conservation

Abstract Biodiversity conservation through protected areas (PAs) is often based on the idea that biodiversity is relatively static. This assumption is increasingly being challenged as species and communities shift their distributions in response to changing environmental conditions. Empirical evidence on the performance of PAs over decades is still sparse or lacking from several environments, although it is needed to understand species dynamics, support modelling of PA performance, assist PA management and ultimately, to achieve global biodiversity conservation goals. In 2021, we resurveyed vegetation of five boreal habitat types (heath forests, paludified forests, sun-exposed sites, mires and eulittoral sites) in Rokua National Park in Finland, where one of the conservation targets is to preserve the flora characteristic of the area. The study sites were originally surveyed in 1945‐49, just before the National Park was established. Study sites have also remained free from the disturbances (forest fires and reindeer grazing) typical of boreal regions. We show that the compositional similarity of plant communities between habitat types has increased over time and is associated with the increase of forest species in several habitat types and the loss of many habitat-specific species. Drivers of change were most often linked to ongoing succession (understory closure) and changes in moisture conditions. Our results suggest that without natural disturbance or appropriate management efforts, the original conservation targets may be compromised over the decades. Our study demonstrates that resurvey of historical vegetation data can be effectively used to estimate long-term PA performance, helping to fill in missing temporal evidence

Biologian kenttäopetus yliopistoissa : yhteistyöllä uuteen nousuun

Kenttäkurssit ovat keskeinen osa biologian ja lähitieteiden opetusta yliopistoissa. Luonnossa tapahtuva opetus kehittää sekä ymmärrystä tieteenalan teoreettisista perusteista että ammatillisia käytännön taitoja. Kenttäkursseilla omat havainnot muodostuvat oppimisen perustaksi muiden oppimistapojen rinnalla. Vaikka kenttäopetuksen tarpeellisuudesta ollaan yksimielisiä, kenttäkursseja uhkaavat yliopistojen rahoituksen väheneminen ja tutkimusasemaverkoston karsiminen. Tässä kirjoituksessa pohdimme, kuinka uhkista huolimatta kenttäopetuksen määrää, laatua ja kustannustehokkuutta voidaan lisätä yliopistojen ja niiden tutkimusasemien välisellä yhteistyöllä.nonPeerReviewe