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Natura 2000 metsaelupaikade struktuuri ja dünaamika hindamine Eestis
No full textA Thesis for applying for the degree of Doctor of Philosophy in Forestry.Väitekiri filosoofiadoktori kraadi taotlemiseks metsanduse erialal.ABSTRACT. Hemiboreal forests, including Natura 2000 forest habitats such as the Western taiga (N9010) and herb-rich spruce forests (N9050), play a crucial role in conserving biodiversity and supporting ecological processes. This doctoral thesis examines the structural complexity, biodiversity, and conservation effectiveness of these habitats using data from 308 permanent forest research plots in Estonia and the Lahemaa National Park inventory. Tree spatial patterns and interactions were analysed using structural indices, while historical and contemporary forest management impacts were assessed through archival materials, aerial photographs, and expert interviews.
The results showed that protected areas had higher understory species diversity, particularly among bryophytes, indicating the presence of specific microhabitats. In N9010 forests, 63 species of conservation importance were identified, including bryophytes (12), vascular plants (7), lichens (17), fungi (11), and beetles (16). The average volume of deadwood ranged from 49.3 to 86.8 m³ ha⁻¹, exceeding values reported in earlier studies in Estonia and Finland. The distribution of deadwood revealed that it was more often found alongside living trees in natural forests, reflecting natural dynamics rather than being solely a result of large disturbances.
Protected forest stands exhibited greater variation in tree diameters and a higher Structural Complexity Index (SCI), indicating more diverse stand structures. Unmanaged spruce forests were significantly more heterogeneous, showing greater species mingling and deadwood clustering. However, only 80% of the N9050 habitats met the Natura 2000 criteria, emphasizing the need for improved habitat mapping and restoration efforts.
The study concludes that achieving a balance between conservation, sustainable management, and restoration requires integrated approaches. Structural indices are effective tools for assessing forest dynamics and supporting adaptive management. Improving deadwood evaluation systems, incorporating biodiversity into forest management plans, and restoring degraded habitats are essential strategies for the long-term conservation of hemiboreal forests.LÜHIKOKKUVÕTE. Hemiboreaalsed metsad, sealhulgas Natura 2000 võrgustikku kuuluvad vanad loodusmetsad (N9010) ja rohunditerikkad kuusikud (N9050), on olulised bioloogilise mitmekesisuse säilitajad ja ökoloogiliste protsesside toetajad. Doktoritöös uuriti nende elupaikade struktuurilist keerukust, elurikkust ja kaitse tõhusust, kasutades Eesti metsa kasvukäigu püsiproovitükkide (308 tk) ning Lahemaa rahvuspargi inventuuri andmeid erineva vanuse ja majandamismõjuga metsadest. Puude ruumilist paigutust ja vastastikmõju analüüsiti struktuuriindeksite abil, lisaks hinnati ajaloolise ja nüüdisaegse metsamajanduse mõju arhiivimaterjalide, aerofotode ja ekspertintervjuude põhjal.
Tulemused näitasid, et kaitsealadel oli alustaimestiku, eriti sammalde liigiline mitmekesisus suurem, mis viitab spetsiifiliste mikroelupaikade olemasolule. N9010 metsades leiti 63 looduskaitselise tähtsusega liiki, sealhulgas samblaid (12), soontaimi (7), samblikke (17), seeni (11) ja mardikaid (16). Keskmine surnud puidu maht varieerus 49,3 ja 86,8 m³ ha⁻¹ vahel, olles kõrgem võrreldes varasemate uuringutega Eestis ja Soomes. Surnud puidu jaotus näitas, et looduslikemates metsades esines surnud puit sagedamini koos elusate puudega ning ei ole vaid suuremate häiringute tulemus.
Kaitsealade puistutes oli suurem puude diameetrite varieeruvus ning kõrgem struktuurse mitmekesisuse indeks (SCI), viidates mitmekesisemale struktuurile. Majandamata kuusikud olid selgelt heterogeensemad, näidates suuremat puuliikide segunemist ja surnud puidu koondumist. Samas vastas vaid 80% N9050 elupaikadest Natura 2000 kriteeriumitele, mis osutab elupaikade parema kaardistamise ning taastamise vajadusele.
Töös järeldatakse, et kaitse, säästva majandamise ja taastamise tasakaalu saavutamiseks tuleb rakendada integreeritud lähenemisviise. Struktuuriindeksid on tõhusad vahendid metsa dünaamika hindamiseks ja paindliku majandamise toetamiseks. Surnud puidu hindamissüsteemi täiustamine, bioloogilise mitmekesisuse arvestamine metsade majandamiskavades ning degradeerunud elupaikade taastamine on peamised strateegiad siinsete metsade kaitseks.Publication of this thesis is supported by the Estonian University of Life Sciences
Jätkusuutlikku mesindust mõjutavad faktorid: patogeenide levik ja diagnostika, mesilasemade aretus
No full textA Thesis for applying for the degree of Doctor of Philosophy in Agricultural Sciences.Väitekiri filosoofiadoktori kraadi taotlemiseks põllumajanduse erialal.ABSTRACT. The decline of pollinators is a global issue caused by diseases, parasites, poor nutrition, pesticides, habitat loss, and climate change. The honeybee (Apis mellifera Linnaeus) is a vital pollinator that helps maintain ecosystem balance and ensure food security. Although the number of managed bee colonies has increased in recent decades, beekeepers continue to face various challenges, including the spread of diseases, the impact of pesticides, and bee health issues. This doctoral theses focuses on identifying several of these threats, investigating major bee diseases, the effects of pollutants, their interactions, and developing potential protection methods.
The study assessed the prevalence of the pathogenic microsporidians Nosema apis and N. ceranae in Estonian and Latvian apiaries. The results revealed that in cooler climates, the recently discovered N. ceranae is beginning to replace N. apis, which may lead to differences in the nature, spread, and control of the disease. Additionally, it was found that the simultaneous presence of both pathogens in bees increases infection levels, indicating a synergistic interaction. Research on Paenibacillus larvae, the pathogen responsible for American foulbrood, highlighted the hidden nature of the disease and its spread's dependence on bee density and climatic conditions. The use of qPCR technology proved effective for early disease detection, helping to reduce the severity and extent of infections.
To ensure the sustainability of beekeeping, it is crucial that queen bees are healthy and their development is not disrupted. Studies on the fungicide active ingredient tebuconazole showed that, while the substance accumulates in beeswax, its transfer to other hive matrices, including royal jelly and developing bees, is minimal. This suggests the presence of a so-called barrier system within the colony that limits potential exposure to contaminants. However, further research is needed to understand the internal movement of pollutants within the hive and their long-term effects. Additionally, the impact of Nosema species on queen bees was investigated, revealing that infected royal jelly caused only minimal developmental disturbances in queens. Future studies should further analyze the effects of pathogens on different members of the bee colony.LÜHIKOKKUVÕTE. Tolmeldajate vähenemine on ülemaailmne probleem, mida põhjustavad haigused, parasiidid, kehv toit, pestitsiidid, elupaikade kadu ja kliimamuutused. Meemesilane (Apis mellifera Linnaeus) on oluline tolmeldaja, kes aitab säilitada ökosüsteemi tasakaalu ja tagada toidujulgeolekut. Majandatavate mesilasperede arv on viimastel aastakümnetel küll kasvanud, kuid mesinikud seisavad jätkuvalt silmitsi mitmesuguste väljakutsetega, sealhulgas haiguste leviku, pestitsiidide mõju ja mesilaste terviseprobleemidega. Doktoritöö keskendub mitmete nende ohtude tuvastamisele, uurides peamisi mesilashaigusi, saasteainete mõju ja nende tegurite koostoimeid ja võimalike kaitsemeetodite väljatöötamisele.
Töö käigus hinnati nosemoosi põhjustavate patogeensete pisieoseliste Nosema apis ja N. ceranae levikut Eesti ja Läti mesilates. Tulemustest selgus, et jahedama kliimaga piirkondades hakkab alles sellel sajandil meemesilastelt avastatud pisieoseline N. ceranae välja tõrjuma N. apis liiki, mis võib kaasa tuua erinevusi haiguse iseloomus, levikus ja tõrjeviisides. Samuti leiti, et mesilasel mõlema patogeeni samaaegne esinemine suurendab nakatumise taset, viidates sünergeerivale koostoimele. Ameerika haudmemädanikku põhjustava patogeeni Paenibacillus larvae uuring tõi esile selle haiguse varjatud olemuse ja leviku sõltuvuse mesilaste tihedusest ning kliimatingimustest. Haiguse varajaseks avastamiseks osutus tõhusaks qPCR-tehnoloogia kasutamine, mis aitab vähendada haigestumiste raskust ja ulatust.
Mesinduse jätkusuutlikkuse tagamiseks on oluline, et mesilasemad oleksid terved ja nende areng ei oleks häiritud. Uuringud fungitsiidi toimeaine tebukonasooli mõju kohta näitasid, et kuigi aine koguneb mesilasvahasse, on selle edasikandumine tarusüsteemi teistele maatriksitele, sealhulgas toitepiimale ja arenevatele mesilastele, minimaalne. See viitab peredes olevale nn barjäärisüsteemile, kus saasteainetega võimalik kokkupuude piiratakse. Saasteainete tarusisest liikumist kui ka pikaajalist mõju tuleb jätkuvalt uurida. Lisaks uuriti Nosema liikide mõju mesilasemadele. Selgus, et nakatunud toitepiim põhjustas mesilasemade arenguhäireid vaid minimaalsel määral. Patogeenide mõju mesilaspere erinevatele liikmetele tuleb edaspidistes uuringutes põhjalikumalt analüüsida.
Kokkuvõttes järeldub doktoritööst, et mesinduse jätkusuutlikkus sõltub haiguste varajasest diagnoosimisest ja tõhusast tõrjest, samuti pestitsiidide ja muude keskkonnaohtude mõistmisest.This research was supported by European Social Fund’s Doctoral Studies and Internationalization Programme DoRa. Publication of this thesis was supported by the Estonian University of Life Sciences
Rakuväliste vesiikulite vahendatav embrüo ja endomeetriumi rakusuhtluse dünaamika
No full textA Thesis for applying for the degree of Doctor of Philosophy in Veterinary Science.Väitekiri filosoofiadoktori kraadi taotlemiseks loomaarstiteaduse erialal.ABSTRACT. There has been a global decline in fertility rates in both humans and animals. Embryo implantation, the process by which the embryo attaches to the endometrium, is the first key step in establishing a pregnancy. Effective communication between the embryo and endometrium prior to implantation is essential for achieving a successful pregnancy. Although various cytokines, growth factors, and hormones are believed to play a role in this dialogue, recent research has highlighted the role of extracellular vesicles (EVs) in this interplay. However, the exact mechanisms of EV function in this context are still not completely understood. The main aim of this doctoral study was to identify a protein indicator of embryo-maternal dialogue mediated via EVs and use it to better understand the factors that influence this critical interplay preceding implantation. Using an in vitro embryo implantation model, we demonstrated that embryonic signals, delivered via EVs, can prime receptive endometrial epithelial cells to enrich their secretory proteome with key proteins vital for embryo implantation. Notably, we identified increased secretion of the MFGE8 protein from endometrial cells in response to embryonic EVs, serving as a marker of embryo-maternal communication. Our findings showed that EV mediated embryo maternal dialogue was influenced by a range of factors, including hormonal levels, the receptivity status of endometrial cells, the trophoblast cell microenvironment, EV dose, and the duration of EV-cell interaction. These results suggest that EV-mediated embryo-maternal communication may rely on both embryonic and endometrial factors. The findings of this PhD thesis could pave the way for a deeper understanding of the mechanisms through which embryonic EVs influence implantation, offering new opportunities to enhance fertility treatments for humans and animals.LÜHIKOKKUVÕTE. Kogu maailmas väheneb nii inimeste kui ka produktiivloomade viljakus. Embrüo ja endomeetriumi
rakusuhtlus enne implantatsiooni on siinkohal kriitiliselt oluline. Molekulaarse signaaliraja
mehhanismid embrüo kinnitumisel endomeetriumile e implanteerumisel ei ole veel selgelt teada.
Hiljutised uuringud näitavad, et tsütokiinide, kasvufaktorite ja hormoonide kõrval on oluline roll
rakuvälistel vesiikulitel (extracellular vesicles, EV). Doktoritöö üldeesmärk oli tuvastada valgumarker,
mis iseloomustab EV-de vahendatavat embrüo ja endomeetriumi rakusuhtluse dünaamikat.
Alameesmärgina uuriti selle valgumarkeri funktsionaalsust, et paremini mõista tegureid, mis
mõjutavad implanteerumisele eelnevaid protsesse. Tulemused näitasid, et EV-de vahendatud
signaalid võivad ette valmistada endomeetriumi epiteelirakke, mille proteoom rikastub embrüo
implanteerumise jaoks oluliste sekretoorsete valkudega. Töös tuvastati ka embrüo ja
endomeetriumi rakusuhtluse markerina toimiva valgu MFGE8 suurenenud eritumine
endomeetriumi rakkudest vastusena embrüo EV-dele. Sekreteerumise suurenemist mõjutasid mitu
tegurit, sh hormonaalne tase, endomeetriumi rakkude vastuvõtlikkus, trofoblastirakkude
mikrokeskkond, EV-de annus ja EV-de mõju kestus. Tulemused viitavad sellele, et EV-de
vahendatavat embrüo ja endomeetriumi rakusuhtlust võivad mõjutada nii embrüonaalsed kui ka
endomeetriumist tulenevad tegurid. Valgu MFGE8 sekretsiooni tase ja in vitro embrüo
implanteerumise mudel toetavad EV-de vahendatud mehhanismide selgitamist embrüo ja
endomeetriumi rakusuhtluses.The publication of this dissertation is granted by the Estonian University of Life Sciences and supported by European Union’s Horizon 2020 research and innovation programme under grant agreement No 857418
COMBIVET and the European Union through Horizon coordination and support actions under grant agreement No. 101079349 OH-Boost
Tollari
No full textPhytoplankton biomass, diversity and abundance in samples collected from Lake Tollari during the period 1961, 1975 and 1976
Year 2025 Soil of Estonia is Skeletic Regosol
No full textFor the Year 2025 Soil of Estonia by the Estonian Soil Science Society (ESSS) was elected Skeletic Regosol (as named by World Reference Base for Soil Resources (WRB)), which is one of subspecies of Coarse Rich Ryhky Soils (by Estonian Soil Classification (ESC)). Although these soils form less than 0,2% from the whole soil cover of Estonia, they merit an attention from the aspect of peculiarities of their forming, which have been taken place on narrow coastal area on the border between sea and mainland. Skeletic Regosols have been formed only on these littoral areas, which is rich mainly in coarse calcareous earth materials as limestone or dolomite containing also small stones (ryhk, pebble, shingle) and large stones. Besides that, these soils are as well rich in different kind of eruptive rocks of the size of small and large stones. The most part of Skeletal Regosols’ coarse fraction was formed under the influence of breaking waves, which were induced by strong sea winds.
The main criteria of Ryhky Soils’ identification after ESC are the content and shape of small stones (Ø 1‒10 cm), water regime of soil cover, and fabric of soil profiles. Ryhky soils are divided into subspecies by the by the shape of small stones. In ryhky soils among others the ryhk fraction is dominated, but in Pebble soils the pebble and in Shingly soils the shingle fractions are dominating.
In the development of Skeletic Regosols or of Shingle soils two development stages is separated. During the first Skeletic Regosols’ abnormal development stage only the primitive shingle rich parent material for these soils have been formed on the border area between mainland and sea. But during this period the soil forming processes are practically absent. During the second development stage of Skeletic Regosols development ie. after with draw of sea water the normal soil forming processes are taken place. As a result of this are formed humus horizons and activated biological cycling on chemical elements and others. In the article the soil forming conditions, coarse earth’s fractions shape and size, development stages of soil profiles, as well soils productivity, humus status, distribution, and agrochemical properties are treated
Viroste
No full textPhytoplankton biomass, diversity and abundance in samples collected from Lake Viroste during the period 1960-2013
Õisu
No full textPhytoplankton biomass, diversity and abundance in samples collected from Lake Õisu during the period 1952-2002
Sensory assessment and consumer acceptability of confectionery products made with pine cones
No full textReceived: January 29th, 2025 ; Accepted: April 8th, 2025 ; Published: April 14th, 2025 ; Correspondence: [email protected] non-timber part of the forest includes mushrooms, berries, cones, shoots etc. The aim of this study was to evaluate consumer acceptability of confectionery products made with pine cones. For the study two pine cone syrups using osmosis were prepared: pine cone syrup with white sugar (PSW) and pine cone syrup with brown sugar (PSB). Four jams were prepared: apple - pine cone jam without added sugar (AC), pine cone jam with white sugar (CW), pine cone jam with brown sugar (CB), and pine cone jam with stevia (CS). Also, four gummy candies were prepared using different thickeners - gelatine (CG), pectin HM (CpHM), pectin LM (CpLM), and agar - agar (CA). To all products sensory evaluation was performed. In total 23 participants participated in this study. The results showed that the PSW had the most intense colour, aroma, taste, and aftertaste, the sweetness in both syrups was the same. The obtained data for jams showed that the CB and AC was the most pleasant in terms of colour, while the CB and CS was the most pleasant in terms of consistency. For the gummy candies’ colour and texture, the highest rated were CpHM. However, for the aroma, taste and aftertaste, the highest acceptance was found in CG. In conclusion, healthier confectionery products with reduced sugar content can be effectively developed by using a non-timber forest resource such as pine cones. This approach allows manufacturers to create confectionary products that satisfy consumer demand for enjoyable sweetness while addressing health concerns
Toxicity of insecticides for adults of Diceraeus melacanthus Dallas, 1851 (Hemiptera: Pentatomidae) in three exposure modes
No full textReceived: July 10th, 2024 ; Accepted: November 11th, 2024 ; Published: January 2nd, 2025 ; Correspondence: [email protected] stink bugs are considered the important pest in second-crop corn cultivation in Brazil, especially when they occur during the early stage of plant development. This study aimed to evaluate the efficiency of insecticides in controlling adults of the Diceraeus melacanthus (Dallas, 1851) stink bug when applied separately in three different modes of exposure. The treatments were evaluated in three modes of exposure of insecticides to D. melacanthus adults as described below: direct contact (direct application of the insecticide to the insects); tarsal contact (exposure through their walking on the treated surface) and ingestion (contact through their feeding on previously treated fresh bean pods). Mortality was assessed at 1, 5, 24 and 48 hours post-exposure. We observed that the percentage of accumulated mortality of D. melacanthus adults was significant through direct contact with chemical treatments. However, if the target insect does not receive direct spraying on its body, indirect contact through its tarsus walking on the treated surface can guarantee a significant final mortality of the stink bugs. In addition, although the mode of exposure through ingestion has shown low mortality, it may also contribute to the final mortality of stink bugs in the field depending on the chemical treatment applied to the crop
Assessing behavioural traits and ecological impacts of invasive crayfish species in freshwater ecosystem
No full textA thesis for applying for the degree of Doctor of Philosophy in: Earth and Environmental Sciences (cycle n. XXXVI), Università degli studi di Pavia; Environmental Sciences and Applied Biology (80130), Eesti Maaülikool.ABSTRACT. Biological invasions occur when species spread to new areas, causing ecological, economic, and social problems. Invasive species can be found in various ecosystems, but freshwater ecosystems are particularly vulnerable due to human activities and environmental changes.
It has been forecasted that the invasion of alien species will increase by up to 36% by 2050, particularly in Europe. Among these invaders, crayfish are expected to see significant increases globally, representing major threats. These large freshwater invertebrates have attracted the attention of freshwater biologists and ecologists because of their ability to travel long distances, high reproductive rates, and adaptability. To better manage invasive species and conserve native ones, it's crucial to understand their behaviour and impacts on ecosystems.
This research study has focused on understanding the behaviour of invasive crayfish and their impacts on freshwater ecosystems. Results highlighted the high adaptability of signal crayfish, which can vary their diet by season and age and, when coexist with native crayfish, they adjust their feeding habits, likely to reduce competition. The study also revealed that signal crayfish individuals coexisting with native crayfish at the invasion front are stronger than those living alone, suggesting a more successful invasion. It has also been found that invasive crayfish have a remarkable ability to disperse over land during droughts, showing their resilience and potential to spread. Additionally, experiments on their reproductive behaviour and the effects of removing female reproductive parts showed that this method could effectively reduce their reproductive capacity.
These findings show the importance of considering behavioural traits in managing invasive species. Implementing control programs for invasive crayfish is crucial to preserving biodiversity and maintaining healthy freshwater ecosystems worldwide.LÜHIKOKKUVÕTE. Bioloogilised invasioonid toimuvad siis, kui liigid levivad uutesse asupaikadesse, põhjustades ökoloogilisi, majanduslikke ja sotsiaalseid probleeme. Invasiivseid liike võib leida erinevates ökosüsteemides, kuid mageveekogude ökosüsteemid on inimtegevuse ja keskkonnamuutuste tõttu eriti haavatavad.
Hinnangute kohaselt suureneb võõrliikide sissetung 2050. aastaks kuni 36%, seda iseäranis Euroopas. Võib eeldada, et invasiivsete vähkide levik laieneb märkimisväärselt kogu maailmas, mis kujutab endast arvestatavat ohtu. Need suured magevee selgrootud on köitnud hüdrobioloogide ja ökoloogide tähelepanu oma võime tõttu läbida pikki vahemaid, aga ka kõrge paljunemis- ja kohanemisvõime tõttu.
Käesolev doktoritöö selgitab invasiivsete vähkide käitumist ja mõju magevee ökosüsteemidele. Tulemused rõhutavad invasiivsete signaalvähkide suurt kohanemisvõimet, mis võimaldab neil muuta oma toitumist sõltuvalt aastaajast ja vanusest. Elades koos kohalike vähkidega, kohandavad nad oma toitumisharjumusi konkurentsi vähendamiseks. Uuringust selgus, et signaalvähi isendid, kes elavad koos kohalike vähkidega, on tugevamad kui üksinduses elavad isendid, mis viitab tugevale invasioonivõimekusele. Leiti, et invasiivsetel vähkidel on märkimisväärne võime levida madalvee ajal üle maa, mis demonstreerib nende vastupanuvõimet ja levikupotentsiaali. Lisaks näitasid vähkide paljunemiskäitumise ja emaste ujujalgade eemaldamise katsed, et see meetod võib tõhusalt pärssida invasiivide paljunemisvõimet.
Doktoritöö tulemused näitavad, kui oluline on invasiivsete liikide ohjamisel võtta arvesse käitumislikke tunnuseid. Invasiivsete vähkide tõrjeprogrammide rakendamine on bioloogilise mitmekesisuse säilitamiseks ja tervete mageveekogude ökosüsteemide säilitamiseks kogu maailmas ülioluline