Browsing by Subject "restoration"

Sort by: Order: Results:

Now showing items 1-17 of 17
  • Michel, Matthieu (Helsingin yliopisto, 2020)
    Hybrid wheat has been the focus of much research for its potential high yield, high protein content and better resistance to biotic and abiotic stresses. Nowadays, only CHA (Chemical Hybridizing Agent) method is used to induce male sterility at a commercial scale. However, this technique is hard to implement on a large production scale and other methods have been investigated for several years. CMS (Cytoplasmic Male Sterility) has been shown to be a promising way to develop hybrid wheat. However, one downside of the technique is the challenging breeding stage step and the associated conversion and restoration process. To fully express the potential gain in yield, the restoration of the cytoplasmic sterility must be complete for the F1 to be fully fertile. In this study, we investigated different methods to assess fertility restoration in nursery and compared the results with the trial notations. The collected data were also used to feed a genomic selection model to predict the behavior of untested hybrids. The results showed a high experimental error of the bagging method originated mostly from human manipulation. The visual scoring showed higher repeatability but was poorly correlated with trial score. A deeper study of the trial scoring revealed an interesting effect coming from the female and an expression of sterility for commercial lines and CHA hybrid checks. Good prediction accuracies were found for genomic selection on both methods, however deeper studies and cross prediction are needed. The multilocation trials remained the best option to score fertility restoration
  • Danquah, Jones Abrefa; Appiah, Mark; Ari, Pappinen (2011)
  • Ojansivu, Tiina (Helsingin yliopisto, 2014)
    Natural disturbances are important for regeneration and biodiversity of forests. Restoration imitates natural disturbances in order to return ecosystems towards its natural state. Knowledge is lacking about the efficiency of restoration, as well as early tree successions. The objects of this study were to investigate the effects of fire and coarse woody debris (CWD) increment on early tree succession and tree species diversity along forest – gap gradient 10 years after restorative partial cuttings in southern Finland. Seedling densities and heights, microhabitat distributions and tree species diversity were compared between four restoration treatments; unburned treatments with 5 and 60 m3 CWD ha-1, and burned treatments with 5 and 60 m3 CWD ha-1. Total seedling densities were tested with two-way analysis of variance. Species diversity was analyzed by species richness and Shannon index, which were tested with two-way analysis of variance. In general, the burned treatments included higher seedling densities and higher seedlings. The different amounts of dead wood revealed differences in deciduous tree species. The density of birch was higher in the treatments with 60 m3 CWD ha-1 and the heights of birch and other deciduous tree species were higher in burned treatment with 60 m3 CWD ha-1. Pine and birch were abundant in the burned treatments. The densities of spruce were very high in the unburned treatment with 5 m3 CWD ha-1, but fairly low in the other treatments. The seedling densities and heights were the lowest in the forest. Seedling densities did not vary significantly between the edge and gap segment. Microhabitat distributions of the coniferous seedlings differed between the unburned and burned treatments, but no clear differences were observed between the low (5 m3 ha-1) and high amount (60 m3 ha-1) of CWD. Microhabitat distributions of seedlings between forest, edge and gap did not differ noticeably, except with spruce in the burned treatments between the edge and gap. Tree species diversity of regeneration was slightly higher in the burned than in the unburned treatments. Different amounts of CWD did not affect the tree species diversity. The tree species diversity was significantly lower in the forest than in the treatment area, but it did not differ between the edge and gap. The results indicate that early tree succession is likely to be more abundant after burning than without. Fire as a restoration tool can be suggested for the regeneration of pine and birch. Dead wood appears to be insignificant for early tree succession. The limited size of restoration areas does not impede the tree succession, since the densities and heights of seedlings were generally the highest near the forest edge. Fire might increase tree species diversity.
  • Pakanen, Veli-Matti; Aikio, Sami; Luukkonen, Aappo; Koivula, Kari (2016)
    The effect of habitat management is commonly evaluated by measuring population growth, which does not distinguish changes in reproductive success from changes in survival or the effects of immigration or emigration. Management has rarely been evaluated considering complete life cycle of the target organisms, including also possible negative impacts from management. We evaluated the effectiveness of cattle grazing in the restoration of coastal meadows as a breeding habitat for small and medium-sized ground-nesting birds by examining the size and demography of a southern dunlin (Calidris alpina schinzii) breeding population. Using a stochastic renesting model that includes within-season variation in breeding parameters, we evaluated the effect of grazing time and stocking rates on reproduction. The census data indicated that the population was stable when nest trampling was prevented, but detailed demographic models showed that the population on managed meadows was a sink that persisted by attracting immigrants. Even small reductions in reproductive success caused by trampling were detrimental to long-term viability. We suggest that the best management strategy is to postpone grazing to after the 19th of June, which is about three weeks later than what is optimal from the farmer's point of view. The differing results from the two evaluation approaches warn against planning and evaluating management only based on census population size and highlight the need to consider target-specific life history characteristics and demography. Even though grazing management is crucial for creating and maintaining suitable habitats, we found that it was insufficient in maintaining a viable population without additional measures that increase nest success. In the presently studied case and in populations with similar breeding cycles, impacts from nest trampling can be avoided by starting grazing when about 70% of the breeding season has past.
  • Koskinen, Markku; Maanavilja, Liisa Maria; Nieminen, Mika; Minkkinen, Kari; Tuittila, Eeva-Stiina (2016)
    Forestry-drained peatlands in the boreal region are currently undergoing restoration in order to bring these ecosystems closer to their natural (undrained) state. Drainage affects the methane (CH4) dynamics of a peatland, often changing sites from CH4 sources to sinks. Successful restoration of a peatland would include restoration of not only the surface vegetation and hydrology, but also the microbial populations and thus CH4 dynamics. As a pilot study, CH4 emissions were measured on two pristine, two drained and three restored boreal spruce swamps in southern Finland for one growing season. Restoration was successful in the sense that the water table level in the restored sites was significantly higher than in the drained sites, but it was also slightly higher than in the pristine sites. The restored sites were surprisingly large sources of CH4 (mean emissions of 52.84 mg CH4 m(-2) d(-1)), contrasting with both the pristine (1.51 mg CH4 m(-2) d(-1)) and the drained sites (2.09 mg CH4 m-(2) d(-1)). More research is needed to assess whether the high CH4 emissions observed in this study are representative of restored spruce mires in general.
  • Primmer, Eeva; Paavola, Jouni (Elsevier, 2021)
    Ecological economics 184: 107001
    The notion of insurance value of ecosystems has both conceptual and practical appeal. However, the operationalisation of the concept does not yet match the typical assumptions about the governance of ecosystems and ecosystem service provision. The articles in this special section provide the first comprehensive effort to address this challenge by offering conceptualizations and examples of metaphorical, analytical and operational applications of the concept of insurance value. Together with this introduction, the articles exemplify the varied uses of the concept of insurance value and the ways in which it is positioned in relation to governance. This introduction highlights that when designing governance solutions for the provision of insurance value from ecosystems, the state of the ecosystem and the activities through which its insurance value generation will be targeted should be clear. The introduction also highlights the importance of considering the assumptions and framings regarding how insurance value is generated in the ecosystems, through preservation, sustainable use or restoration, or through a combination of these strategies. Because of the distinct analytical and governance implications of these strategies, future research should specifically address the institutional conditions for applying any one of them.
  • Heino, Jani; Alahuhta, Janne; Bini, Luis Mauricio; Cai, Yongjiu; Heiskanen, Anna-Stiina; Hellsten, Seppo; Kortelainen, Pirkko; Kotamaki, Niina; Tolonen, Kimmo T.; Vihervaara, Petteri; Vilmi, Annika; Angeler, David G. (Wiley & Sons, 2021)
    Biological Reviews 96(1), 89-106
    The Anthropocene presents formidable threats to freshwater ecosystems. Lakes are especially vulnerable and important at the same time. They cover only a small area worldwide but harbour high levels of biodiversity and contribute disproportionately to ecosystem services. Lakes differ with respect to their general type (e.g. land-locked, drainage, floodplain and large lakes) and position in the landscape (e.g. highland versus lowland lakes), which contribute to the dynamics of these systems. Lakes should be generally viewed as ‘meta-systems’, whereby biodiversity is strongly affected by species dispersal, and ecosystem dynamics are contributed by the flow of matter and substances among locations in a broader waterscape context. Lake connectivity in the waterscape and position in the landscape determine the degree to which a lake is prone to invasion by non-native species and accumulation of harmful substances. Highly connected lakes low in the landscape accumulate nutrients and pollutants originating from ecosystems higher in the landscape. The monitoring and restoration of lake biodiversity and ecosystem services should consider the fact that a high degree of dynamism is present at local, regional and global scales. However, local and regional monitoring may be plagued by the unpredictability of ecological phenomena, hindering adaptive management of lakes. Although monitoring data are increasingly becoming available to study responses of lakes to global change, we still lack suitable integration of models for entire waterscapes. Research across disciplinary boundaries is needed to address the challenges that lakes face in the Anthropocene because they may play an increasingly important role in harbouring unique aquatic biota as well as providing ecosystem goods and services in the future.
  • Toure, Ibrahim; Larjavaara, Markku; Savadogo, Patrice; Bayala, Jules; Yirdaw, Eshetu; Diakite, Adama (2020)
    Land degradation (LD) in Mali is prevalent and leads to an enduring environmental and humanitarian crisis. Farmers' ecological knowledge has proven to be a valuable tool in addressing its challenges. How farmers perceive LD affects how they deal with induced risks, and their responses to these perceptions will shape restoration options and outcomes. Therefore, this study assessed farmers' perceptions of LD along a climatic gradient in three regions of Mali. We interviewed 270 farmers, and we analyzed their responses using descriptive statistics and Spearman rank‐order correlation. We found that the respondents were aware of LD and have identified its key indicators and its impacts on their livelihoods. Moreover, we found that farmers' perceptions are not influenced by gender, age, or education level, but rather by agricultural training, participation in agricultural labor, the practice of fallowing, shortage of firewood, livestock, household size, appearance of some plant species and famine. Additionally, farmers' perceptions of LD vary along the climatic gradient as they correlate to different variables in each agro‐ecological zone. LD's impacts, however, decrease in severity along the north–south gradient, although they are linked to the same variables. As LD is seen through a reduction of ecosystem services provisioning capacity because of the local communities' heavy dependence on natural resources, actions should be geared towards agronomic and vegetative land management options. Such actions should prioritize context‐specific soil and water conservation techniques and proven indigenous practices.
  • Valin, Marjo (Helsingfors universitet, 2014)
    Suomenlinna is a sea fortress that consists of eight islands and it is a very popular tourist attraction in Helsinki. The vegetation of Suomenlinna has been influenced by its location in the outer archipelago and by the previous military use. The primary aim of this study was to explore the composition and abundance of plant species in soil seed banks of dry meadows at Kustaanmiekka. The established vegetation of the dry meadows was studied in 2009. Soil seed samples were collected in April 2011 from ten dry meadows located around Kustaanmiekka. The samples were taken from two different soil layers: 0-4,5 cm and 4,5-9 cm. Seedling emergence method was chosen to study the seed banks. It was carried out from May to October 2011 in the Viikki campus greenhouse at the University of Helsinki. A total of 5887 seeds from 83 taxa germinated from the soil seed bank samples. The most common species were Berteroa incana (L.) DC., Festuca rubra L. and Potentilla argentea var. argentea. The seed banks contained a few polemochorous species (Berteroa incana, Epilobium hirsutum L. and Silene latifolia Poir. ssp. alba (Mill.) Greuter & Burdet which were brought in Finland with military troops. Noteworthy species found only in the seed bank were Descurainia sophia (L.) Webb ex Prantl and Matricaria recutita L.. The seed density varied from 5030 to17600 seeds/m2. Compared to the short-lived species, the amount of perennial species and their seeds was greater in the seed banks. The number of species and seeds differed between the dry meadows. A 2 luonnonalue had the highest number of species while Makeavesialtaiden luonnonalue and Kustaanmiekan sisäosan hiekkataso had the highest number of seeds. The total number of species and the average number of seeds didn´t correlate with the content of the main nutrients or humus in the soil, nor with soil pH or soil type. The soil seed banks could be utilized in the maintenance of the dry meadows in Kustaanmiekka by uncovering and breaking the soil. Rare meadow species that reproduce from seeds and that are still present in the vegetation would also benefit from this. More research is needed to determine the best method to utilize the soil seed banks when seeking to recruit as many species from the seed bank as possible.
  • Marques, Maria Jose; Schwilch, Gudrun; Lauterburg, Nina; Crittenden, Stephen; Tesfai, Mehreteab; Stolte, Jannes; Zdruli, Pandi; Zucca, Claudio; Petursdottir, Thorunn; Evelpidou, Niki; Karkani, Anna; AsliYilmazgil, Yasemen; Panagopoulos, Thomas; Yirdaw, Eshetu; Kanninen, Markku; Luis Rubio, Jose; Schmiedel, Ute; Doko, Adrian (2016)
  • Kuuluvainen, Timo; Angelstam, Per; Frelich, Lee E.; Jogiste, Kalev; Koivula, Matti; Kubota, Yasuhiro; Lafleur, Benoit; Macdonald, Ellen (2021)
    Global forest area is declining rapidly, along with degradation of the ecological condition of remaining forests. Hence it is necessary to adopt forest management approaches that can achieve a balance between (1) human management designs based on homogenization of forest structure to efficiently deliver economic values and (2) naturally emerging self-organized ecosystem dynamics that foster heterogeneity, biodiversity, resilience and adaptive capacity. Natural disturbance-based management is suggested to provide such an approach. It is grounded on the premise that disturbance is a key process maintaining diversity of ecosystem structures, species and functions, and adaptive and evolutionary potential, which functionally link to sustainability of ecosystem services supporting human well-being. We review the development, ecological and evolutionary foundations and applications of natural disturbance-based forest management. With emphasis on boreal forests, we compare this approach with two mainstream approaches to sustainable forest management, retention and continuous-cover forestry. Compared with these approaches, natural disturbance-based management provides a more comprehensive framework, which is compatible with current understanding of multiple-scale ecological processes and structures, which underlie biodiversity, resilience and adaptive potential of forest ecosystems. We conclude that natural disturbance-based management provides a comprehensive ecosystem-based framework for managing forests for human needs of commodity production and immaterial values, while maintaining forest health in the rapidly changing global environment.
  • Yirdaw, Eshetu; Monge Monge, Adrian; Austin, Denis; Toure, Ibrahim (2019)
    In Laos, there are extensive shifting cultivation areas and regrowth forests spontaneously established on fallow lands. The aims of the study were to conduct a comparative study of old-growth and regrowth forests in terms of structure, woody species diversity and composition as well as to investigate the potential role of regrowth forests in the conservation and restoration of degraded forest lands in Laos and the tropics in general. Systematic plot sampling was used to survey the floristic diversity, species composition and structure of old-growth and regrowth forests. Concentric circular plots with an area of 200 m2 and 500 m2 were laid on line transects. A total of 24 plots were sampled from two sites. In comparison to regrowth forests, old-growth forests had higher structural heterogeneity because of higher canopy height variations, vertical stratification, and tree sizes and their variations. Species richness and diversity indices values were similar, but abundance and species composition were significantly different between old-growth and regrowth forests. It appears that species richness recovers first followed by forest structure and species composition. Regrowth forests are important for in situ conservation of tropical biodiversity and they can also serve as a conduit for the restoration of degraded lands and forests. Regrowth forests provide habitats, serve as buffer zones around the fragmented old-growth forests, function as source of propagules, and enhance landscape connectivity. Utilization of regrowth forests for restoration purposes is comparatively inexpensive. Regrowth forests should be given the due considerations in the national forest conservation and restoration policy of Laos.
  • Hotulainen, Aino Henriikka (Helsingin yliopisto, 2018)
    Tässä kirjallisuuskatsauksessa on haluttu selventää juurihoidetun hampaan restauraatiomenetelmien vaikutusta hampaan pitkäaikaisennusteessa. Tavoitteena on selvittää, mikä restauraatiomateriaali ja minkä tyyppinen restauraatio on optimaalisin ratkaisu juurihoidetun hampaan hoidossa missäkin tapauksessa. Kun kliinikko tuntee materiaalin ja tekniikan valintaan vaikuttavat tekijät, hän osaa suositella parasta ratkaisua potilaalle. Kirjallisuuskatsausta varten on haettu artikkeleita, joissa esitellään eri restauraatiomenetelmiä ja vertaillaan sekä juurihoidon laadun ja restauraation merkitystä hampaan ennusteelle, että eri menetelmillä restauroituja hampaita. Kirjallisuuskatsaus koostuu kahdesta osasta. Ensin selvennetään erilaiset juurihoidetun hampaan restauraatiomenetelmät. Sen jälkeen tarkastellaan tarkemmin tutkimustuloksia edellä esitellyistä aiheista. Viimeisessä kappaleessa pohditaan tutkimusten tuloksia, ja tehdään yhteenveto. Artikkeleita läpikäydessä korostuu, että aiheesta ei ole tehty riittävästi laadukasta tutkimusta. Tutkimusten otokset, seuranta-ajat, kriteerit, sekä hoitotekniikat, -materiaalit ja – ympäristöt vaihtelivat runsaasti. Muutamia johtopäätöksiä voidaan kuitenkin esittää. Adekvaatti juurihoito on merkittävin hampaan pitkäaikaisennustetta parantava tekijä. Adekvaatin juurihoidon lisäksi adekvaatisti toteutettu restauraatio parantaa hampaan ennustetta edelleen, ja parhaat ennusteet saadaankin sekä adekvaatilla juurihoidolla, että restauraatiolla varustetuille hampaille. Juurihoidetussa hampaassa 1-2 pinnalle ulottuvat kaviteetit voidaan yleensä restauroida yhdistelmämuovilla. Kun juurihoidetun hampaan kaviteetti ulottuu kolmelle pinnalle tai yli, voikin olla mielekästä harkita onlay-tyyppisen täytteen, endo-kruunun tai perinteisen kruunun valmistusta. 4-5 pinnan kaviteeteille paras ja kestävin vaihtoehto lienee proteettinen hammaskruunu epäsuoralla menetelmällä valmistettuna.
  • Kangas, Laura (Helsingfors universitet, 2013)
    Forested wetlands throughout the world are valuable habitats; especially in relatively species-poor northern regions, they can be considered biological hotspots. Unfortunately, these areas have been degraded and destroyed. In recent years, however, the biological importance of wetlands has been increasingly recognized, resulting in the desire to restore disturbed habitats or create in place of destroyed ones. Restoration work is taking place across the globe in a diversity of wetland types, and research must be conducted to determine successful techniques. As a result, two studies of the effects of wetland restoration and creation were conducted in forested wetlands in northern Michigan and southern Finland. In North America, northern white-cedar wetlands have been declining in area, despite attempts to regenerate them. Improved methods for successfully establishing northern white-cedar are needed; as a result, the target of the first study was to determine if creating microtopography could be beneficial for white-cedar recruitment and growth. In northern Europe, spruce swamp forests have become a threatened ecosystem due to extensive drainage for forestry. As part of the restoration of these habitats, i.e. rewetting through ditch blocking, Sphagnum mosses are considered to be a critical element to re-establish, and an in-depth analysis of how Sphagnum is responding to restoration in spruce swamp forests has not been previously done. As a result, the aim of the second study was to investigate the ecophysiological functioning of Sphagnum and feather mosses across a gradient of pristine, drained, and restored boreal spruce swamp forests.
  • Yirdaw, Eshetu; Kanninen, Markku; Elfadl, Mohamed; Tsegai, Daniel (Finnish Society of Forest Science, 2017)
    Silva Fennica
  • Piha, Aura (Helsingfors universitet, 2011)
    Fire is an important driver of the boreal forest ecosystem, and a useful tool for the restoration of degraded forests. However, we lack knowledge on the ecological processes initiated by prescribed fires, and whether they bring about the desired restoration effects. The purpose of this study was to investigate the impacts of low-intensity experimental prescribed fires on four ecological processes in young commercial Scots pine (Pinus sylvestris) stands eight years after the burning. The processes of interest were tree mortality, dead wood creation, regeneration and fire scar formation. These were inventoried in twelve study plots, which were 30 m x 30 m in size. The plots belonged to two different stand age classes: 30-35 years or 45 years old at the time of burning. The study was partly a follow-up of study plots researched by Sidoroff et al. (2007) one year after burning in 2003. Tree mortality increased from 183 stems ha-1 in 2003 to 259 stems ha-1 in 2010, corresponding to 15 % and 21 % of stem number respectively. Most mortality was experienced in the stands of the younger age class, in smaller diameter classes and among species other than Scots pine. By 2010, the average mortality of Scots pine per plot was 18%, but varied greatly ranging from 0% to 63% of stem number. Delayed mortality, i.e. mortality that occurred between 2 and 8 years after fire, seemed to become more important with increasing diameter. The input of dead wood also varied greatly between plots, from none to 72 m3 ha-1, averaging at 12 m3 ha-1. The amount of fire scarred trees per plot ranged from none to 20 %. Four out of twelve plots (43 %) did not have any fire scars. Scars were on average small: 95% of scars were less than 4 cm in width, and 75% less than 40 cm in length. Owing to the light nature of the fire, the remaining overstorey and thick organic layer, regeneration was poor overall. The abundance of pine and other seedlings indicated a viable seed source existed, but the seedlings failed to establish under dense canopy. The number of saplings ranged from 0 to 12 333 stems ha-1. The results of this study indicate that a low intensity fire does not necessarily initiate the ecological processes of tree mortality, dead wood creation and regeneration in the desired scale. Fire scars, which form the basis of fire dating in fire history studies, did not form in all cases.
  • Zusevica, Austra; Celma, Santa; Neimane, Santa; von Cossel, Moritz; Lazdina, Dagnija (2022)
    Cutaway peatland is a marginal land, which without further management is an unfavourable environment for plant growth due to low bearing capacity, high acidity and unbalanced nutrient composition of the soil. After wood-ash application, the soil becomes enriched with P and K, creating better conditions for tree growth. In addition to being economically viable, tree plantations ensure long-term carbon storage and promote habitat restoration. In a three-year term, we studied how distance from a drainage ditch and three different doses of wood-ash-5, 10, and 15 tons per hectare-affect the diversity of vascular plants in a tree plantation on a cutaway peatland. Plant species richness, vegetation cover and composition were positively affected by the distance from the drainage ditch and application with fertiliser, but in most cases, fertiliser dose had no significant effect. Both cover and species diversity were not affected by the planted tree species. In a tree plantation, herbaceous plants provide soil fertility by decay and recycling, and reduce mineral leaching in the long term. Since vascular plants play an important role in both the development of habitats and tree growth, it is important to know how multiple factors influence the development of vegetation in tree plantations.