Kaitsealuste päevaliblikate ökoloogia Eestis

Väitekirja elektrooniline versioon ei sisalda publikatsioone.Paljude Euroopa päevaliblikaliblikaliikide seisund on halvenemas. Eduka looduskaitselise tegevuse jaoks on vaja mõista ohustatud liikide põhilisi ökoloogilisi nõudmisi. Vastsena taimedel toituvatele putukatele on sobiva taimeliigi olemasolu mõistagi peamine keskkonna sobivuse näitaja. Toidutaime olulisus siiski erineb monofaagsete (toituvad ühel taimeliigil), oligofaagsete (toituvad mõnel suguluses oleval liigil) ja polüfaagsete (toituvad mitmetel erinevatel taimeliikidel) putukate jaoks, samuti komplitseerib olukorda toidutaimekasutuse geograafiline varieerumine. Seetõttu on oluline teada, kas mõnel ohustatud liblikaliigil on lokaalselt spetsiifilisemad taime-eelistused kui regioonis üldiselt. Oma töös uurisin viie Euroopas ohustatuks peetava päevaliblikaliigi toidutaimekasutust Eestis kasutades erinevaid laborkatseid, välitöid ning levikuanalüüsi. Uuritavateks liikideks olid sõõrsilmik, vareskaera-aasasilmik, suur-kuldtiib, teelehe-mosaiikliblikas ja suur-mosaiikliblikas. Töö tulemused näitavad, et sõõrsilmik ja vareskaera-aasasilmik on polüfaagsed, mistõttu ühegi konkreetse taimeliigi olemasolu ei määra elupaiga kvaliteeti ega limiteeri nende liikide levikut. Leidsime siiski, et vareskaera-aasasilmikul esineb mikroelupaigalisi eelistusi. Suur-kuldtiiva peamiseks toidutaimeks on tömbilehine oblikas, mis on kooskõlas liigi leviku analüüsi tulemusega. Nimelt eelistab liblikas kraavide ja inimasustusega alasid – need loovad usutavasti oblikale soodsaid kasvutingimusi. Teelehe-mosaiikliblikas näib Eestis olevat monofaagne harilikul peetrilehel, mis on siiani jäänud ainsaks tõendatud selle liblika toidutaimeks. Suur-mosaiikliblika levik on seotud hariliku saarega – looduses on röövikuid leitud vaid sellelt taimeliigilt; liblikas on levinud vaid seal, kus toidutaim esineb. Viie uuritud liblikaliigi ohustatuse hindamine ei olnud küll käesoleva töö otseseks eesmärgiks, kuid autorile teadaolevalt ei viita miski nende liikide populatsioonide kahanemisele Eestis. Kõikide uuritud liblikaliikide olukord Eestis on hea, kuid teelehe- ja suur-mosaiikliblika jaoks võib tulevik siiski olla ebakindlam. Seda just maakasutusmuutuste ning kiiresti leviva seenhaiguse tõttu, mis mõjutavad nende liblikate peamisi toidutaimi, vastavalt peetrilehte ja saart. Kogutud informatsiooni on kindlasti võimalik kasutada nendes piirkondades, kus nimetatud viie liblikaliigi looduskaitseline seisund on halvem ning ka tähelepanu vajavate kohalike populatsioonide kaitseks Eestis.Numerous European butterflies are declining. To develop successful conservation practices it is necessary to understand the basic ecological requirements of the endangered species. The presence of a suitable host species is the main criterion for herbivorous insects. The importance of the host plant is different for monophagous (feeding only on one host species), oligophagous (feeding on few related species) and polyphagous (feeding on wide range of host species) insects, as well as host plant use may vary geographically. Therefore, it is vital to know whether any endangered species has more specific food preferences locally than believed for the region as whole. I explored the importance of host plant in Estonia for endangered buttefly species Lopinga achine, Coenonympha hero, Lycaena dispar, Euphydryas aurinia and E. maturna, using different laboratory experiments, field work and analyses of distribution. We found out that L. achine and C. hero are polyphagous, so the presence of a certain plant species does not determine the habitat quality or limit the distribution of these butterflies. Still, C. hero seems to have preferences at microhabitat level. Primary host plant for L. dispar in Estonia is the broad-leaved dock (Rumex obtusifolius), which is consistent with the results contry-wide distribution analyses: this butterfly species prefers areas with ditches and human settlemen, these factors likely creating favourable conditions for the host species. E. aurinia appears to be functionally monophagous on devil's-bit scabious (Succisa pratensis), which has remained the only confirmed host plant in the country. E. maturna is related to ash (Fraxinus excelsior): caterpillars have been found only on ash trees in the wild; the butterfly species is distributed only in the areas where the host species is present. Assessment of the conservation status of the five butterfly species was not among the aims of the present study. However, there is no direct evidence of decline for any of these species in Estonia. The conservation status of all five butterfly species appears favourable. Although the the future of E. aurinia and E. maturna looks more uncertain due to changes in agriculture practice and a fungal disease which affect their main host plants. Local populations of these five butterfly species may still require attention. Also, the information gathered must be used in other regions where these species may be of higher conservation concern

Microclimate in hollow trees and how it affects an inhabiting beetle species, Osmoderma eremita

Studies of species' responses to microclimatic conditions have increased our understanding of their habitat requirements and possible responses to climate warming. However, little is known about the role of microclimate for insects inhabiting hollow trees. We explored the relationship between tree characteristics and microclimate, and analysed how the microclimate in tree-hollows affects the occurrence and body size of an endangered beetle species, Osmoderma eremita. We placed temperature data-loggers in wood mould (= loose material in tree-hollows) and surveyed O. eremita in 47 hollows in oak pastures in south-eastern Sweden. We found that tree characteristics previously known to be associated with occurrence of beetle species confined to tree-hollows (larger diameters, more wood mould, entrances higher up, and not directed upwards) tend to decrease moisture and moisture variation, while their effects on temperature and temperature fluctuations differ during different seasons. This indicates that microclimatic conditions are important for beetles in hollow trees, and many specialised species seem to avoid conditions that are too moist. O. eremita occurred more frequently in trees with a warmer and more stable microclimate, while adult body size decreased with a warmer microclimate. A positive effect of a warmer microclimate was expected, since the study was done near the northern margin of the species' range. O. eremita is confined to living in hollow trees, which may be due to the microclimate there being more stable in comparison to both the ambient climate and the microclimate in standing and downed dead wood

Microclimatic conditions mediate the effect of deadwood and forest characteristics on a threatened beetle species, Tragosoma depsarium

While climate change has increased the interest in the influence of microclimate on many organisms, species inhabiting deadwood have rarely been studied. Here, we explore how characteristics of forest stands and deadwood affect microclimate inside deadwood, and analyse how this affects wood-living organisms, exemplified by the red-listed beetle Tragosoma depsarium. Deadwood and forest variables explained much of the variation in temperature, but less of the variation in moisture within deadwood. Several variables known to influence habitat quality for deadwood-dependent species were found to correlate with microclimate. Standing deadwood and an open canopy generates warmer conditions in comparison to downed logs and a closed canopy, and shaded, downed and large-diameter wood have higher moisture and more stable daily temperatures than sun-exposed, standing, and small-diameter wood. T. depsarium occupancy and abundance increased with colder and more stable winter temperatures, and with higher spring temperatures. Consistently, the species occurred more frequently in deadwood items with characteristics associated with these conditions, i.e. downed large-diameter logs occurring in open conditions. Conclusively, microclimatic conditions were found to be important for a deadwood-dependent insect, and related to characteristics of both forest stands and deadwood items. Since microclimate is also affected by macroclimatic conditions, we expect species' habitat requirements to vary locally and regionally, and to change due to climate warming. Although many saproxylic species preferring sun-exposed conditions would benefit from a warmer climate per se, changes in species interactions and land use may still result in negative net effects of climate warming

Density of dispersal sources affects to what extent restored habitat is used: A case study on a red-listed wood-dependent beetle

When restoring habitats, an important question is whether the spatial distribution of habitat affects its contribution to biodiversity conservation. In Sweden, high-cut stumps are routinely created at forestry operations. By counting the number of exit holes of a red-listed beetle, Peltis grossa, we assessed occurrence, colonisations and extinctions per high-cut stump and beetle density per clear-cut. We found a threshold, at which the form of the relationship between density of the beetle and density of high-cut stumps per clear-cut changes abruptly. The beetle density was considerably higher where the density of high-cut stumps exceeded 4.5 per hectare. Such thresholds can be explained by colonisation-extinction processes. Observed colonisation-extinction dynamics were consistent with metapopulation theory. For instance, there was a positive relationship between colonisation rate and a connectivity measure that considered beetle abundance and distance for each high-cut stump in the surrounding area. However, the relationship disappeared when using a connectivity measure solely based on the distance of the high-cut stumps. The observed threshold implies that P. grossa benefits from aggregating the same total number of created high-cut stumps into fewer clear-cuts. This is because the total area with a density of high-cut stumps exceeding the threshold increases, and this expands the number and size of dispersal sources. Therefore, P. grossa and other species that reveal thresholds in their distribution patterns, are favoured when conservation measures are more spatially aggregated than what is resulting from current Swedish policy

Interaction between regional temperature and shade level shapes saproxylic beetle communities

AimThe 'concept of relative constancy of habitats' assumes that species differ in their habitat preferences depending on the regional temperature so that all populations experience similar microclimatic conditions. Our aim was to assess the relevance of this concept by disentangling the effects of shade level and regional temperature on southern and northern distributed saproxylic (=dead wood dependent) beetle species.LocationSweden.MethodsWe established a field experiment by placing 435 logs of Norway spruce (Picea abies) along shade gradients in six regions differing in regional temperature (along a 1200 km latitudinal gradient). For each log, we sampled the saproxylic beetle community and calculated the Community Temperature Index (CTI), indicating to what extent the community is dominated by southern or northern species.ResultsSpecies richness and total abundance were better explained by shade level, whereas species composition was better explained by study region. In colder regions, CTI varied along the shade gradient, whereas in warmer regions, CTI was more similar along the shade gradient. Moreover, in colder regions, the number of southern species was higher in sun-exposed logs, whereas in warmer regions, the number of southern species was higher in shaded logs. This supports the concept of relative constancy of habitats. In contrast, northern species preferred shaded conditions regardless of the regional temperature.Main ConclusionsRegional temperature, shade level and resulting microclimate are important drivers of species richness, total abundance and composition. Occurrence patterns of saproxylic beetle species follow to some extent the concept of relative constancy of habitats since their habitat preferences vary with regional temperature. Northern species are of conservation concern due to disadvantages by climate warming and clear-cutting. They are favoured by preserving forests with rarely disturbed canopies

Metapopulation dynamics over 25 years of a beetle, Osmoderma eremita, inhabiting hollow oaks

Osmoderma eremita is a species of beetle that inhabits hollows in ancient trees, which is a habitat that has decreased significantly during the last century. In southeastern Sweden, we studied the metapopulation dynamics of this beetle over a 25 year period, using capture-mark-recapture. The metapopulation size had been rather stable over time, but in most of the individual trees there had been a positive or negative trend in population development. The probability of colonisation was higher in well-connected trees with characteristics reflecting earlier successional stages, and the probability of extinction higher in trees with larger diameter (i.e. in later successional stages), which is expected from a habitat-tracking metapopulation. The annual tree mortality and fall rates (1.1% and 0.4%, respectively) are lower than the colonisation and extinction rates (5-7%), indicating that some of the metapopulation dynamics are due to the habitat dynamics, but many colonisations and extinctions take place for other reasons, such as stochastic events in small populations. The studied metapopulation occurs in an area with a high density of hollow oaks and where the oak pastures are still managed by grazing. In stands with fewer than ten suitable trees, the long-term extinction risk may be considerable, since only a small proportion of all hollow trees harbours large populations, and the population size in trees may change considerably during a decade

Protected area designation and management in a world of climate change: A review of recommendations

Climate change is challenging conservation strategies for protected areas. To summarise current guidance, we systematically compiled recommendations from reviews of scientific literature (74 reviews fitting inclusion criteria) about how to adapt conservation strategies in the face of climate change. We focussed on strategies for designation and management of protected areas in terrestrial landscapes, in boreal and temperate regions. Most recommendations belonged to one of five dominating categories: (i) Ensure sufficient connectivity; (ii) Protect climate refugia; (iii) Protect a few large rather than many small areas; (iv) Protect areas predicted to become important for biodiversity in the future; and (v) Complement permanently protected areas with temporary protection. The uncertainties and risks caused by climate change imply that additional conservation efforts are necessary to reach conservation goals. To protect biodiversity in the future, traditional biodiversity conservation strategies should be combined with strategies purposely developed in response to a warming climate

Consistent imprints of elevation, soil temperature and moisture on plant and arthropod communities across two subarctic landscapes

1. Factors shaping arthropod and plant community structure at fine spatial scales are poorly understood. This includes microclimate, which likely plays a large role in shaping local community patterns, especially in heterogeneous landscapes characterised by high microclimatic variability in space and in time.2. We explored differences in local microclimatic conditions and regional species pools in two subarctic regions: Kilpisj & auml;rvi in north-west Finland and Varanger in north-east Norway. We then investigated the relationship between fine-scale climatic variation and local community characteristics (species richness and abundance) among plants and arthropods, differentiating the latter into two groups: flying and ground-dwelling arthropods collected by Malaise and pitfall traps, respectively. Arthropod taxa were identified through DNA metabarcoding. Finally, we examined if plant richness can be used to predict patterns in arthropod communities.3. Variation in soil temperature, moisture and snow depth proved similar between regions, despite differences in absolute elevation. For each group of organisms, we found that about half of the species were shared between Kilpisj & auml;rvi and Varanger, with a quarter unique to each region.4. Plants and arthropods responded largely to the same drivers. The richness and abun-dance of both groups decreased as elevation increased and were positively correlated with higher soil moisture and temperature values. Plant species richness was a poor predictor of local arthropod richness, in particular for ground-dwelling arthropods.5. Our results reveal how microclimatic variation within each region carves pro-nounced, yet consistent patterns in local community richness and abundance out of a joint species pool

Data om mikroklimat i ihåliga träd och hur det påverkar ett boende skalbaggar, Osmoderma eremita

The data includes measured habitat characteristics, microclimatic variables, and species data collected with mark-recapture method. It was used for analyses to explore microclimate in tree hollows in relation to tree characteristics; and how these variables affect the occurrence and body size of Osmoderma eremita (hermit beetle). Manuscript: "Microclimate in hollow trees and how it affects an inhabiting beetle species, Osmoderma eremita". The study is in English. Species-related data is collected with mark-recapture method (pitfall trap). Moisture/humidity is measured with soil moisture meter (GS3 sensor; Decagon Devices). Temperature data is recorded with Lascar EL-USB-1 data-loggers. OE_MC_publish_ambient.tsv: 9766 R × 9 C OE_MC_publish_internal.tsv: 9766 R × 55 C OE_MC_publish_R.tsv: 47 R × 67 C OE_MC_publish_RH.tsv: 53 R × 31 C Specimens_data_publish_b_length-habitat-MC.tsv: 256 R × 24 C Specimens_data_publish_Recapture.tsv: 500 R × 6 CData inkluderar uppmätta habitategenskaper, mikroklimatiska variabler och artdata som samlats in med mark-återfångstmetoden. Den användes för analyser för att utforska mikroklimat i trädgropar i relation till trädets egenskaper; och hur dessa variabler påverkar förekomsten och kroppsstorleken av Osmoderma eremita (läderbagge). Manuskript: "Mikroklimat i ihåliga träd och hur det påverkar en levande skalbaggarart, Osmoderma eremita". Studien är på engelska. Species-related data is collected with mark-recapture method (pitfall trap). Moisture/humidity is measured with soil moisture meter (GS3 sensor; Decagon Devices). Temperature data is recorded with Lascar EL-USB-1 data-loggers. OE_MC_publish_ambient.tsv: 9766 R × 9 C OE_MC_publish_internal.tsv: 9766 R × 55 C OE_MC_publish_R.tsv: 47 R × 67 C OE_MC_publish_RH.tsv: 53 R × 31 C Specimens_data_publish_b_length-habitat-MC.tsv: 256 R × 24 C Specimens_data_publish_Recapture.tsv: 500 R × 6

Regional climate affects habitat preferences and thermal sums required for development of the Eurasian spruce bark beetle, Ips typographus

In recent years, the outbreaks of the Eurasian spruce bark beetle (Ips typographus) have become more frequent and severe, while temperatures have been rising. Our understanding of the consequences of climate warming can be improved by comparing the performance of I. typographus between geographical regions with different climates. We applied that approach by placing out Norway spruce logs at sites selected along a 1300 km north -south gradient in Sweden to study the effect of regional climate and microclimate on I. typographus. To obtain a microclimatic gradient at each site, we placed the logs at sun-exposed edges and in the shaded inner forest (10 m or 50 m from stand edges). We assessed the probability of colonisation of I. typographus and the thermal sums required for complete development.The species' habitat preferences differed along the climate gradient including six geographical regions: in cooler regions, a higher proportion of sun-exposed logs was colonised in comparison to the shaded ones, while that difference was much smaller in warmer regions. The thermal sum needed for development tended to increase with warmer regional climate. Seasonal thermal sum exceeded the requirements for development of two generations per year in all three shade levels in the warmest region while in the coldest region two generations were only possible in some of the sun-exposed logs.Outbreaks of I. typographus are more frequent and severe in regions with a warmer climate, and our study reveals two explanations for this: first, I. typographus has more suitable breeding sites in warmer regions, as shaded logs inside the forest offer additional suitable habitat; second, the potential population growth increases with the probability of completing two fully established generations per year. We recommend that after stormfellings, wind-felled trees are removed before they are colonised by I. typographus to decrease the outbreak risk. The observed difference in habitat preferences between geographical regions implies that, in cooler sites in the north, it is enough to remove recently wind-felled spruces that are sun-exposed, such as along edges, while in the south, also trees in more shaded conditions inside forests are a suitable substrate for I. typographus. In a warming climate, the increased risk and severity of I. typographus outbreaks is a factor making it less attractive to use Norway spruce in forestry