The European Modern Pollen Database (EMPD) project

Modern pollen samples provide an invaluable research tool for helping to interpret the quaternary fossil pollen record, allowing investigation of the relationship between pollen as the proxy and the environmental parameters such as vegetation, land-use, and climate that the pollen proxy represents. The European Modern Pollen Database (EMPD) is a new initiative within the European Pollen Database (EPD) to establish a publicly accessible repository of modern (surface sample) pollen data. This new database will complement the EPD, which at present holds only fossil sedimentary pollen data. The EMPD is freely available online to the scientific community and currently has information on almost 5,000 pollen samples from throughout the Euro-Siberian and Mediterranean regions, contributed by over 40 individuals and research groups. Here we describe how the EMPD was constructed, the various tables and their fields, problems and errors, quality controls, and continuing efforts to improve the available dat

Taimestiku mitmekesisuse peegeldumine kaasaegsete järvesetete õietolmus

Intensiivne põllu- ja metsamajandus, linnastumine ja looduslike alade liigkasutamine, aga ka kliima soojenemine, on viinud bioloogilise mitmekesisuse vähenemiseni ning sellest on saanud globaalse tähtsusega probleem. Seetõttu on teadlaste huvi biodiversiteeti mõjutavate mehhanismide uurimise vastu suur. Tuleviku liigirikkuse kujunemist muutuva kliima ja maakasutuse tingimustes aitab ennustada mineviku elustiku mitmekesisuse ja selle muutumise uurimine. Teadmisi mineviku bioloogilisest mitmekesisusest on aga raske saada, kuna relevantseid kirjalikke allikaid on vähe ning needki pärinevad kuni mõne sajandi tagusest ajast. Kõige paremaks ja ajas kaugemale ulatuvamaks infoallikaks mineviku taimestiku kohta on setetes talletunud fossiilne õietolm. Oma väliskesta omaduste tõttu säilib õietolm anaeroobsetes setetes tuhandeid aastaid. Teadust, mis sellise fossiilse õietolmu põhjal mineviku taimkatet uurib nimetatakse palünoloogiaks. Fossiilsel õietolmul põhinevad taimkatte rekonstruktsioonid on seni olnud üldiselt tüpoloogilised ja kvalitatiivsed, kirjeldades maastiku avatuse suurenemist või vähenemist ning inimmõju intensiivistumist indikaatorliikide põhjal. Kvantitatiivseid taimkatte rekonstruktsioonid on takerdunud kolme põhilise faktori taha: 1) õietolmu taksonoomia ei vasta alati taimede taksonoomiale (üks õietolmutüüp võib vastata erinevat järku taksonile - liik, perekond või sugukond – või ka liigirühmale, mis ei moodustagi taksonit), 2) erinevad taimeliigid produtseerivad erineval hulgal õietolmu (näiteks produtseerib üks männi isaskäbi 600 000 õietolmutera, samas üks aaslina taim vaid 100 tolmutera), 3) taimeliikide õietolmu levimisstrateegiad on erinevad (tuultolmlemine, putuktolmlemine jne.), mistõttu setetes esinevate ja taimkattes leiduvate õietolmutaksonite osakaalude vahel pole lihtsat seost. Alles alates 1960. aastatest on aga hakatud välja töötama kvantitatiivse taimkatte rekonstrueerimise meetodeid, mis oma arengutes on teinud viimase kümne aasta jooksul tohutu hüppe ning mille tulemusena on ilmunud juba mõned taimkatte kvantitatiivsed rekonstruktsioonid. Samas on taimestiku mitmekesisuse rekonstruktsioonid endiselt harvad, kuna nii teoreetilised kui praktilised teadmised taimestiku liigirikkuse ja järvesetetesse talletuva õietolmu taksonite liigirikkuse vahelistest seostest on kasinad. Käesoleva doktoritöö eesmärgiks on olnud uurida taimestiku ja setetes leiduva õietolmu liigirikkuse vahelisi seoseid ning välja arvutada taimkatte kvantitatiivse rekonstrueerimise seisukohast olulised parameetrid – õietolmu baasala (ala, mis peegeldab setetes leiduva õietolmu järgi kohalikku taimestikku) suurus Lõuna-Eesti väikejärvedele ning peamiste tuultolmlevate taimetaksonite õietolmu produktsiooni hinnangud Läänemere idarannikul. Töö põhineb tänapäevase õietolmu ja taimestiku andmestikul, kusjuures õietolmu andmed on kogutud Lõuna-Eesti väikejärvede setete kõige ülemisest kihist ning taimestiku ning taimkatte andmed nende järvede ümbrusest. Töö tulemusena leiti, et Lõuna-Eesti väikejärvede jaoks on õietolmu baasala suurus 1400¬-1600 m järvest ning seda, et puud on suuremad õietolmu produtseerijad kui rohttaimed. Kuigi ainult 20% taimeliikide arvust esines uuritud järve setetes, leiti ometi tugev positiivne seos järvesetetes leidunud tolmutüüpide arvu ja taimestiku liigirikkuse vahel, mis tulenes eelkõige putuktolmlevatest taksonitest. Olulisteks faktoriteks, mis määrasid nii floristilise kui palünoloogilise mitmekesisuse, olid maastiku avatus ja mosaiiksus, viidates sellega, et mõõdukas maastiku avatus tõstab liigirikkust nii maastikus kui järvesettes. Nii väljaarvutatud õietolmu baasala kui õietolmu produktsiooni hinnanguid saab nüüd rakendada mineviku taimkatte kvantitatiivsete rekonstruktsioonide tegemisel. Käesoleva töö tulemusi saab kasutada setteprofiilide interpreteerimisel hindamaks fossiilse õietolmu põhjal mineviku taimestiku mitmekesisust. Analoogilisi uurimusi tuleks läbi viia ka teistes regioonides, et saada laiemat pilti maastiku, taimestiku ja õietolmu vahelistest seostest.Publication of the thesis is supported by the Estonian University of Life Sciences and by the Doctoral School of Earth Sciences and Ecology created munder the auspices of European Social Fun

Relative pollen productivity estimates of major anemophilous taxa and relevant source area of pollen in a cultural landscape of the hemi-boreal forest zone (Estonia)

Estimates of relevant source area of pollen (RSAP) and relative pollen productivity (PPE) are critical parameters for quantitative reconstructions of past vegetation and land cover. This study provides estimates for PPE relative to Poaceae for ten taxa, characterizing the cultural landscape of south Estonia and the RSAP for 40 lakes with an average radius of approximately 100 m (22-274 m, average 101 m) in the region. We evaluate the effects on those estimates of various combinations of factors, such as the analytical methods (i.e. three Extended R value (ERV) sub-models), the distance-weighting methods used to determine plant abundance, and alternative classification schemes of vegetation and land cover data around study sites. Different combinations of ERV sub-models and distance-weighting methods lead to estimates of RSAP varying between 1500 m and 2000 m. The differences in the estimated RSAP are strongly related to the patch size of the vegetation data. According to ERV sub-model 1, which shows the highest log-likelihood among the three sub-models, most of the taxa have PPE that are higher (Picea, Pin us, Quercus), slightly higher (Salix, Artemisia, Filipendula) or similar (Betula, Cerealia, Cypreraceae) to that of Poaceae. The three ERV sub-models produce only slightly different PPE. However, the selection of distance-weighting method for vegetation has considerable influence on the PPE values. The inverse distance-weighting methods, which do not consider inter-taxonomic differences in pollen dispersal, tend to underestimate PPE for taxa with heavy pollen grains and overestimate PPE for taxa with light pollen grains, compared to the results obtained using other methods that consider taxon specific pollen-dispersal. General land-cover data, based on the classification scheme similar to the CORINE (COoRdination of Information on the Environment) database, could be used for estimating the RSAP and PPE, although some potential problems remain when the classification is too simplified and consolidated. (C) 2011 Elsevier B.V. All rights reserved

The role of landscape structure in determining palynological and floristic richness

The associations between floristic and palynological richness and landscape structure were studied based on modern pollen-vegetation data from a patchy cultural landscape in southern Estonia (northern temperate vegetation zone). Nine study sites (small lakes and their surrounding vegetation) represent land cover gradient from closed forest to semi-open vegetation. Floristic richness (number of species) and floristic richness of pollen types (number of pollen-equivalent taxa) were used to describe the vegetation within the radius of 250 m from the pollen sampling sites. Palynological richness was calculated to describe the modern pollen samples diversity. Landscape structure was estimated on the basis of landscape openness and three landscape diversity measures: richness of community patches, Simpson evenness of community patches and Simpson diversity of community patches. To study the effect of the spatial scale of landscapes on the vegetation-landscape and pollen-landscape associations, landscape structure was estimated within eight radii (250-2,000 m) around each lake. The results showed that landscape openness was the most important determinant of both floristic richness and palynological richness in southern Estonia and that landscape diversity estimated by Simpson diversity index was also significantly associated with the richness estimates. Floristic and palynological richness were significantly positively correlated with landscape structure within the radii greater than 1,000 m from the pollen sampling sites, which is similar to the estimated Relevant Source Area of Pollen in southern Estonia. We conclude that within one floristic or climatic region, palynological richness gives reliable estimates about the variation in floristic richness and landscape structure; however, caution must be taken when comparing pollen-inferred vegetation diversities from different regions or when interpreting fossil pollen records from times with highly different vegetation associations

Palynological richness and pollen sample evenness in relation to local floristic diversity in southern Estonia

The relationship between palynological diversity and floristic diversity was studied on the basis of sediment surface sample pollen data from nine small lakes and vegetation data within a 250 m radius from the lake shore of each. The nine study areas are situated in the patchy cultural landscape of Southern Estonia and were chosen to represent landscape changes along a gradient from closed forest to open vegetation. Two diversity measures - richness and evenness - were used to compare the palynological and floristic data. A total of 307 plant species were recorded in the vegetation representing 127 pollen types. Only 52 pollen types were recorded in the sediment surface samples of which 43 had parent plants in the vegetation. Significantly lower floristic richness was found in closed surroundings than in more open surroundings. Study sites with open vegetation also had significantly higher palynological richness (number of pollen types recorded in surface sediments). The additional pollen types recorded in surface sediments from open vegetation were widespread types mostly of insect-pollinated taxa such as Ranunculus, Rubiaceae, Melampyrum, Filipendula, Potentilla or Vaccinium. The parent plants of these pollen types were frequent in the landscape. This suggests that the main mechanism governing palynological richness in this study was not floristic diversity but rather variance in pollen productivity. Since woodland has a higher pollen production than open areas (grassland and fields) per unit land surface, open areas tend to show a better representation of slightly rarer but widespread herb pollen types. No relationship was found between palynological and floristic diversity of wind-pollinated taxa and tree taxa partly because the pollen source area for these pollen types is much larger than 250 m. (C) 2011 Elsevier B.V. All rights reserved

Wooded meadows of Estonia: conservation efforts for agricultural landscape

We provide an overview of the amount and ecological condition of wooded meadows throughout Estonia after significant changes in agriculture in the second part of 20th century. We also present the first attempt to estimate the success of recent conservation efforts for wooded meadows. Our analysis is based on recent exhaustive inventories. We found that Estonia, despite a decrease of the area in wooded meadows by two orders of magnitude during the 20th century, still has about 8400 ha remaining of which approximately 5800 ha are meadows with, at the least, an intermediate conservation value. The latter is directly dependent on mowing regime. Efforts to preserve wooded meadows include establishment of protected areas and financial support for mowing. The national conservation subsidy has been useful and supportive for wooded meadows, however the total amount of this subsidy has been small compared to the area that could be supported. The much larger funds of agri-environmental subsidies have largely not been available for wooded meadows. Moreover, there has been no record keeping about subsidisation of semi-natural grasslands using agricultural support schemes. Although the preservation of some good examples of wooded meadows in Estonia seems guaranteed, further degradation of this valuable habitat type on a national scale is very probable.vo

The European Modern Pollen Database (EMPD) project

Modern pollen samples provide an invaluable research tool for helping to interpret the quaternary fossil pollen record, allowing investigation of the relationship between pollen as the proxy and the environmental parameters such as vegetation, land-use, and climate that the pollen proxy represents. The European Modern Pollen Database (EMPD) is a new initiative within the European Pollen Database (EPD) to establish a publicly accessible repository of modern (surface sample) pollen data. This new database will complement the EPD, which at present holds only fossil sedimentary pollen data. The EMPD is freely available online to the scientific community and currently has information on almost 5,000 pollen samples from throughout the Euro-Siberian and Mediterranean regions, contributed by over 40 individuals and research groups. Here we describe how the EMPD was constructed, the various tables and their fields, problems and errors, quality controls, and continuing efforts to improve the available data

Erratum to: The European Modern Pollen Database (EMPD) project

Unfortunately, the list of authors contains a number of duplications, omissions and other errors in the original publication of the article. The correct list appears in this erratum