296 research outputs found
Attitudes towards protection of biodiversity in forests
No full textThe focus of nature protection through area protection in Swedish forests has for a long time been on boreal, subalpine and alpine areas. Large areas have of this reason been protected in northern Sweden, while the protection of forest in southern Sweden, and especially in the temperate zone, have been almost neglected. Only 2,5 per cent of the land area in the southernmost county in Sweden, the county of Skåne, has some kind of protection today and considerably less of the forest is protected. Some possible reasons for this distorted balance of share of protected forest between northern and southern Sweden are:
* The large share of state-owned forest in northern Sweden has facilitated the work with area protection.
* The large share of forest owned by non-industrial private forest owners in southern Sweden and the relatively small estates in southern Sweden has been a hindrance in the implementation of area protections.
* The long history of land use in southern Sweden has made it difficult to find areas with high nature values for protection, and these areas are very often scattered in the landscape.
The need of protection of biodiversity in the forests of southern Sweden is largely due to the long history of land use. Southern Sweden has much more threatened species than northern Sweden, not only due to the land use history, but also due to the generally higher number of species in the south.
The area of protected forest has however increased much in Skåne during recent years and many private forest owners have been involved in this process. The County Forestry Board of Södra Götaland has been the most active authority in the number of concerned estates and thereby influenced forest owners. The County Board of Skåne and the Swedish Environmental Protection Agency have implemented some new nature reserves and national parks. These areas are usually of larger size but concern in relation to their size fewer estates and thereby there are less forest owners influenced. The encroachment of these forms of protection is however most often to be considered of larger magnitude than the habitat protection and nature conservation agreements that are implemented by the County Forestry Board. This is not only due to the larger size of the areas but also due to differences in the forms of agreements.
A large number of private forest owners have been influenced by the implementation of area protection of forest, and there is a lack of knowledge how the forest owners perceive these processes, even though some studies have been performed in the field. This study is a part of a joint Nordic project with the task "to study effects of various policy instruments and develop proposals concerning the development of policies within the field".
A questionnaire, consisting of a set of questions in common for the joint project with some adjustments for regional differences and completed with a set of questions specific for this study, was sent to 241 addressees in Skåne. The addressees were private forest owners or previous private forest owners who had been involved in a process with the objective of an area protection of forest in the form of one or more of the protection types below:
* National park
* Nature reserve
* Habitat protection
* Nature conservation agreement
The real response rate was 53 per cent and for another ten per cent the reason for absence of answers is known. The average age of the respondents was 58 years and 78 per cent were men. Most respondents had purchased their estate, often in combination with inheritance and gift. The respondents were rather independent of their income from the forestry on the estate. The average share of income from the forestry on the estate was 15 per cent while the median was much lower with five per cent. Still most of the respondents valued commercial wood the highest among the goods from their forest. Another important good was recreation. The change in share of income from the forestry on the estate after the area protection was implemented was small. The largest loss of income had the respondents with the 25 per cent highest shares of income from the forest. These respondents had on average ten per cent less of their income from the forestry on the estate after the area protection was implemented.
Most respondents associated the concept biodiversity with species and ecosystems and/or with conservation of nature. A majority had the opinion that the owner of the land also is owner of the biodiversity, while they did not consider this ownership to imply an economical responsibility of preserving it. Most respondents thought that the state should have the main economical responsibility of the protection of forest. Many were satisfied with how large share of the forest that was protected in the Swedish private forest, and many more wanted the area of protected forest to increase than wanted it to decrease. However, they were not willing to protect forest without compensation.
The type of compensation that was preferred by most respondents was a yearly compensation, only 31 per cent wanted a once-and-for-all payment. The once-and-for-all payment is the today most common way of compensating the landowners for the encroachment of an area protection and 82 per cent of the respondents for whom the protection process was completed had also gotten this kind of compensation. Many also wanted new land in exchange, which was only realised in one case, and is maybe often less feasible due to small size of the area. The respondents preferred agreements with the authorities were they remained owner of the land and the rights following it. Also this is in contrast to what is most common, the authorities usually buy the land or the right to use the land. They also wanted to be involved in the management of the protected areas, the only form of agreement that today involves the landowner in the management is the nature conservation agreements.
The respondents that had been involved in the protection process to a large extent were in general more satisfied with it. Among the respondents that had been involved to a very or rather large extent there were 86 and 72 per cent, respectively, satisfied with the process, while the corresponding figure among the ones that had been involved to a very small extent was 8 per cent. The County Forestry Board had succeeded better than the County Board and the Environmental Protection Agency in involving the forest owner into the process. Thereby there were also more of the respondents satisfied with the process among the ones that had their main contact with the County Forestry Board. An underlying cause of this can be that the County Forestry Board's work usually concerns smaller areas, but it can also be so due to that the County Forestry Board has a long tradition and experience of contact with and education of forest owners.
A majority of the respondents did not consider the compensation they had received to cover the economic losses of forest production due to the protection. Many of the respondents who considered themselves to be self-active in their forestry, did not consider the compensation to cover the loss of employment. Just a few of the respondents had made some changes in the management of the remaining part of their forest due to the implementation of the area protection. Neither changes positive to biodiversity nor changes negative to biodiversity were made at any considerable extent.
The addressees were given 17 statements to which they were going to respond, to what extent they agreed with the statements. The statements concerned protection of biodiversity in general, protection of biodiversity in forest, and protection of biodiversity in the respondent's forest. There was no significant difference in attitude of the respondents due to which of the categories the statement belonged. The respondents were positive to nature protection, independent of what level it concerned. But it has to be mentioned that the statements concerning protection of biodiversity on the respondents own estate included the condition that the respondent was fully compensated for the encroachment. However, when the answers were analysed in relation to different characteristics of the respondents there were some differences found. Which sex the respondent belonged to was of importance for the level of agreement when the statement concerned protection of biodiversity in general. Women were more positive towards protection of biodiversity in general than men. No difference of this kind was found when the statement concerned protection of biodiversity on the estate of the respondent.
The characteristics most important for how the forest owner responded to the statements concerning protection of biodiversity on his or her estate were:
* General education
* Membership of an environmental organisation
* Size of forest
* Income from the forestry on the estate
* Share of own work on the estate
* Felling per hectare
Some characteristics were correlated with the size of the forest. Sex, income from the forestry on the estate and share of own work on the estate showed a correlation with the size of forest. The most important characteristics for the respondents' attitudes towards protection of biodiversity were characteristics closely connected with the intensity of the management of the forest on the estate. Many of these characteristics were also correlated with the size of the forest.Tyngdpunkten i det svenska naturskyddet har länge legat i de boreala, subalpina och alpina delarna av Sverige. Stora områden har därmed skyddats i norra Sverige, medan skyddet av skog i södra Sverige till stor del har förbisetts. Bara 2,5 procent av landarealen och en betydligt mindre del av skogen i Skåne är idag skyddad. Några anledningar till snedvridningen av skyddad skog mellan södra och norra Sverige är:
- Den stora andelen av statligt ägd skog i norra Sverige har underlättat processen med naturskydd där.
- Den stora andelen skog som ägs av privata enskilda skogsägare och den relativt stora ägosplittringen i södra Sverige har varit ett hinder i reservatsbildning och naturskyddsarbetet.
- Markanvändningen i södra Sverige har pågått under längre tid än i de norra delarna av landet. Detta har försvårat arbetet med att finna områden lämpliga för reservatsbildning.
Ett frågeformulär skickades till 241 adressater i Skåne. Adressaterna var enskilda privata skogsägare som hade varit berörda av en process med målsättningen att en eller flera av nedanstående skyddsformer skulle införas på deras mark. Frågeformuläret bestod av en bas av frågor som var gemensamma för det Nordiska projektet. Dessa anpassades dock till regionala förhållanden och kompletterades med ytterligare ett antal frågor av relevans för denna studie. De skyddsformer som var aktuella var:
- Nationalpark
- Naturreservat
- Biotopskydd
- Naturvårdsavta
Fertilization in Boreal and Temperate Forests and the Potential for Biomass Production
No full textForest fertilization is one of the most efficient methods in forest management to increase the short-term production of biomass. In this context, this chapter provides a brief background of the physiological response of trees to fertilization and increased nutrient availability. Furthermore, we shall describe different fertilization regimes and demonstrate the potentials of fertilization in enhancing biomass production, which will be performed by presenting relevant literature and some unpublished results. This chapter will also elaborate on some ideas for developing fertilization in operational forestry.</p
Changes in composition of bottom and field layer vegetation as an effect of fertilisation in coniferous forest
No full textMost studies dealing with the effects on the ecosystem of nitrogen fertilisation or deposition show changes in the field and bottom layer vegetation of forests. According to some studies even low levels of added nitrogen result in changes in the field-layer vegetation. Effects of added nitrogen on vegetation can be divided into immediate and long-term effects. The immediate effects are caused by the toxicity of nitrogen on plants, especially bryophytes and lichens. The long-term effects are likely an effect of an accumulation of nitrogen in the system, through increased competition in the ground vegetation and decreased insolation due to a closing canopy. Ecosystem changes are dependent on several preconditions, such as: initial composition of the vegetation, initial nutrient status and light conditions. In general tall and fast growing species are favoured by addition of nitrogen, while species less responsive to increased levels of nitrogen in terms of increased growth are disfavoured. Species which can utilise nitrate through enhanced nitrate-reductase activity are promoted. In some vegetation types the interference of pathogens has been shown to mediate the change in vegetation. The species richness of a site is to large extent determined by other factors than availability of nutrients, like soil acidity. Many bryophytes and lichens decrease in abundance as an effect of increased levels of nitrogen. A plausible explanation is their low growth potential. A few studies on the activity of cyanobacteria associated with bryophytes and lichens have shown a significant decrease in activity when nitrogen was added to the site. Many studies indicate that competition between strata (e.g. from the tree canopy) is essential for the response in ground vegetation when a forest is fertilised
Bumblebees mediate landscape effects on a forest herb's population genetic structure in European agricultural landscapes
No full textSpatially isolated plant populations in agricultural landscapes exhibit genetic responses not only to habitat fragmentation per se but also to the composition of the landscape matrix between habitat patches. These responses can only be understood by examining how the landscape matrix influences among-habitat movements of pollinators and seed vectors, which act as genetic linkers among populations. We studied the forest herb Polygonatum multiflorum and its associated pollinator and genetic linker, the bumblebee Bombus pascuorum, in three European agricultural landscapes. We aimed to identify which landscape features affect the movement activity of B. pascuorum between forest patches and to assess the relative importance of these features in explaining the forest herb's population genetic structure. We applied microsatellite markers to estimate the movement activity of the bumblebee as well as the population genetic structure of the forest herb. We modelled the movement activity as a function of various landscape metrics. Those metrics found to explain the movement activity best were then used to explain the population genetic structure of the forest herb. The bumblebee movement activity was affected by the cover of maize fields and semi-natural grasslands on a larger spatial scale and by landscape heterogeneity on a smaller spatial scale. For some measures of the forest herb's population genetic structure, that is, allelic richness, observed heterozygosity and the F-value, the combinations of landscape metrics, which explained the linker movement activity best, yielded lower AICc values than 95% of the models including all possible combinations of landscape metrics.Synthesis: The genetic linker, B. pascuorum, mediates landscape effects on the population genetic structure of the forest herb P. multiflorum. Our study indicates, that the movement of the genetic linker among forest patches, and thus the pollen driven gene flow of the herb, depends on the relative value of floral resources in the specific landscape setting. Noteworthy, the population genetic structure of the long-lived, clonal forest herb species correlated with recent land-use types such as maize, which have been existing for not more than a few decades within these landscapes. This underscores the short time in which land-use changes can influence the evolutionary potential of long-lived wild plants.Bumblebees can connect isolated populations of forest herbs within agricultural landscapes by moving between forest patches. These movements are influenced by specific aspects of the landscape. These same landscape aspects also partly explain the population genetic structure of a forest herb species associated with bumblebees as pollinators.imag
Muutokset pohjoisten metsien aluskasvillisuudessa ja maaperän mikrobiyhteisöissä vuosikymmenten ja -satojen ajalla : Luontaiset ja muuttuneet kehityskulut
No full textAbstractHuman 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.Original papersOriginal papers are not included in the electronic version of the dissertation.Muurinen, L., Huusko, K., Ahonen, S. H. K., Oksanen, J., & Markkola, A. M. (2022). Temporal and local-scale drivers determine soil fungal and bacterial communities along forested primary succession gradient. Manuscript in preparation.Happonen, K., Muurinen, L., Virtanen, R., Kaakinen, E., Grytnes, J.-A., Kaarlejärvi, E., Parisot, P., Wolff, M., & Maliniemi, T. (2021). Trait‐based responses to land use and canopy dynamics modify long‐term diversity changes in forest understories. Global Ecology and Biogeography, 30(9), 1863–1875. https://doi.org/10.1111/geb.13351Self-archived versionMuurinen, L., Oksanen, J., Vanha-Majamaa, I., & Virtanen, R. (2019). Legacy effects of logging on boreal forest understorey vegetation communities in decadal time scales in northern Finland. Forest Ecology and Management, 436, 11–20. https://doi.org/10.1016/j.foreco.2018.12.048Self-archived versionTiivistelmäIhmistoiminnan 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.OsajulkaisutOsajulkaisut eivät sisälly väitöskirjan elektroniseen versioon.Muurinen, L., Huusko, K., Ahonen, S. H. K., Oksanen, J., & Markkola, A. M. (2022). Temporal and local-scale drivers determine soil fungal and bacterial communities along forested primary succession gradient. Manuscript in preparation.Happonen, K., Muurinen, L., Virtanen, R., Kaakinen, E., Grytnes, J.-A., Kaarlejärvi, E., Parisot, P., Wolff, M., & Maliniemi, T. (2021). Trait‐based responses to land use and canopy dynamics modify long‐term diversity changes in forest understories. Global Ecology and Biogeography, 30(9), 1863–1875. https://doi.org/10.1111/geb.13351Rinnakkaistallennettu versioMuurinen, L., Oksanen, J., Vanha-Majamaa, I., & Virtanen, R. (2019). Legacy effects of logging on boreal forest understorey vegetation communities in decadal time scales in northern Finland. Forest Ecology and Management, 436, 11–20. https://doi.org/10.1016/j.foreco.2018.12.048Rinnakkaistallennettu versioAcademic dissertation to be presented with the assent of the Doctoral Programme Committee of Technology and Natural Sciences of the University of Oulu for public defence in Auditorium IT116, Linnanmaa, on 18 November 2022, at 12 noonAbstract
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
Forest fertilization transiently increases soil CO2 efflux in young Norway spruce stands in Sweden
No full textLate-rotation fertilization of Norway spruce stands is a frequently used management tool in Fennoscandia to increase timber yields. Meanwhile, the growing demand for renewable resources has sparked great interest in earlier and repeated fertilizer application but it remains unclear how this affects carbon dioxide (CO2) fluxes in the understory, especially forest floor respiration (Rff). This study investigated the effects of forest fertilization on Rff and net forest floor exchange (NFFE) in young, nitrogen (N) limited Norway spruce stands in southern Sweden. In a short-term dose experiment, Rff and NFFE were recorded during 2016 after varying doses of N (0, 150, 300, or 450 kg ha-1 of N, hereafter N0, N150, N300, N450) were added to circular, 3-m-diameter plots in April. In a second, long-term experiment, two stand-level fertilizer applications with 150 kg ha-1 of N on each occasion were performed in 2014 and 2016 and Rff was measured at semi-regular intervals from mid-2013 to the end of 2017. In the dose experiment, fertilization increased Rff by 23 %, 81 % and 55% in the N150, N300 and N450 treatments, respectively. Under well-lit conditions, the N300 and N450 treatments significantly enhanced photosynthetic CO2 uptake of the forest floor vegetation by 97 % and 66 %, respectively, while the N150 treatment had no significant effect. The results of the long-term experiment indicate an initial stimulation of Rff, but this effect was transient. Our findings imply that fertilization in young Norway spruce stands, using the N150 dose (the typical dose used in Swedish forestry), may cause a transient burst in Rff that is far outweighed by nutrient-driven increases in forest floor photosynthesis under favourable light conditions prior to canopy closure
Variable time lags in genetic response of three temperate forest herbs to 70 years of agricultural landscape change
No full textContextAgriculture-driven land-use changes over the past decades have not only reduced the amount of habitat for species but also influenced the genetic exchange among the remaining fragmented populations. Many recent studies have found a delayed response in population genetic diversity and differentiation of species in fragmented habitats to past landscape disturbances, a so-called time lag. However, the specific role of species' individual reproductive traits and the population genetic measures used remain poorly understood.ObjectivesWe examined the impact of past and current agricultural landscape composition in temperate Europe on the population genetic structure of three long-lived, slow-colonizing forest herb species - Anemone nemorosa, Oxalis acetosella and Polygonatum multiflorum, which vary in their reproductive traits.MethodsWe considered four time points in history (mid-1900s, 1985, 2000 and 2017) to identify the potentially different length of time that is needed by each species to respond to landscape change. We also explored the impact of using different genetic measures in quantifying the time lags.ResultsOur findings show that despite substantial landscape alterations about 70 years ago, the mid-1900s landscape composition was not reflected in the current genetic diversity and differentiation of the three species. This indicates a possible unexpected quick genetic adjustment of these species. Nevertheless, by combining the signals of multiple genetic measures, we found that O. acetosella, which reaches sexual maturity earlier than the other two species and is self-compatible, showed signs of faster genetic adjustment to these landscape changes. In contrast, A. nemorosa and P. multiflorum, which take longer to reach sexual maturity, might exhibit longer time lags that were beyond this study's time frame.ConclusionsThis study underscores the importance of considering the species' reproductive traits and especially the role of temporal scales of different genetic measures when investigating the impact of landscape history on current population genetic structures
Functional composition of temperate forest trees under chronic ungulate herbivory
No full textQuestion: Functional plant traits often express consistent changes along ecological gradients and, hence, are often used as indicators of environmental change (e.g. nutrient availability, temperature changes). Besides being driven by edaphic conditions, functional plant composition is filtered by herbivory, and traits responsive to nutrient availability often coincide with those related to palatability or resistance to browsing. We hypothesized that herbivory may distort the ways in which traits are expressed along environmental gradients.Location: Bialowieza National Park, Poland.Methods: We used a long-term controlled, exclosure experiment in the Bialowieza National Park to study tree functional trait expression and plant indicator values, with and without large ungulate browsing, along a natural soil fertility gradient.Results: Browsing largely reduced the functional diversity of regenerating trees, indicated by multivariate analysis and Rao's Quadratic Entropy (RQE), and altered how several traits change with increasing fertility. Browsing led to an increase in specific leaf area (SLA) on poorer sites. RQE showed a hump-backed trend along the fertility gradient, indicating the largest functional diversity at intermediate fertility. However, this pattern was not affected by browsing. Unlike the morphological tree traits, trends of light and N plant indicator values along the gradient were unaffected by browsing.Conclusions: These results highlight how the expression of plant traits resulting from one driver (soil fertility) can be modified by another driver (herbivory,) and stress the importance of taking herbivory into account when using plant traits as indicators of large-scale processes (e.g. climate change). Furthermore, the results suggest that plant indicator values may be more robust towards these effects, while compiled indices such as RQE could mask considerable functional turnover. Several traits (e.g. SLA) are strongly connected to nutrient cycling. The development, driven by browsing, towards higher SLA on poorer sites may thus cause a positive feedback effect on site fertility that drives an increase in nutrient availability. This may in turn have implications for ecosystem functionality. Hence, the large reduction in functional diversity revealed at the scale of this study may in the long term have implications on multiple ecosystem processes
Patterns of local plant diversity and community saturation in deciduous forests in Europe
No full textQuestionsHow do local forest conditions and characteristics at the forest patch - scale and landscape - scale affect plot-scale plant diversity in Europe? Do these patterns vary between forest specialists and generalists? Do community saturation patterns differ between forests varying in their surrounding landscape type?LocationDeciduous forests sampled along a European gradient from southwest to northeast comprising eight regions in five countries (France, Belgium, Germany, Sweden, Estonia).MethodsWe examined the effects of local conditions assessed by means of Ellenberg indicator values (soil moisture, soil nitrogen, soil pH, light availability), patch-scale characteristics (patch-scale plant diversity, forest patch age, forest patch size) and a landscape-scale variable (representing low and high connectivity of forest patches) on plot-scale plant diversity, separately for forest specialist and generalist species. Additionally, we ran regression models to examine community saturation patterns.ResultsWe found patterns of niche partitioning among forest specialists and generalists. Low light availability and medium soil moisture favored forest specialists, while generalists were mostly present at higher light availability and medium and high soil moisture. In general, we found the highest plot-scale diversity at medium soil pH. Patch-scale diversity showed a positive impact on plot-scale diversity and plots in the high-connectivity landscape had a higher diversity than plots in the low-connectivity landscape. Further, we observed a high degree of community saturation in both landscape types.ConclusionThe positive impact of a high connectivity of forest patches on local plant diversity emphasizes the importance of small semi-natural habitats like tree lines, unused field margins and hedgerows to enhance the potential dispersal of forest plants across agricultural landscapes. Community saturation patterns revealed the increasing relevance of local conditions and processes for plot-scale diversity when patch-scale diversity increases
- …
