Kadri Tali

Advantages of Volunteer-Based Biodiversity Monitoring in Europe

Without robust and unbiased systems for monitoring, changes in natural systems will remain enigmatic for policy makers, leaving them without a clear idea of the consequences of any environmental policies they might adopt. Generally, biodiversity-monitoring activities are not integrated or evaluated across any large geographic region. The EuMon project conducted the first large-scale evaluation of monitoring practices in Europe through an on-line questionnaire and is reporting on the results of this survey. In September 2007 the EuMon project had documented 395 monitoring schemes for species, which represents a total annual cost of about 4 million euro, involving more than 46,000 persons devoting over 148,000 person-days/year to biodiversity-monitoring activities. Here we focused on the analysis of variations of monitoring practices across a set of taxonomic groups (birds, amphibians and reptiles, mammals, butterflies, plants, and other insects) and across 5 European countries (France, Germany, Hungary, Lithuania, and Poland). Our results suggest that the overall sampling effort of a scheme is linked with the proportion of volunteers involved in that scheme. Because precision is a function of the number of monitored sites and the number of sites is maximized by volunteer involvement, our results do not support the common belief that volunteer-based schemes are too noisy to be informative. Just the opposite, we believe volunteer-based schemes provide relatively reliable data, with state-of-the-art survey designs or data-analysis methods, and consequently can yield unbiased results. Quality of data collected by volunteers is more likely determined by survey design, analytical methodology, and communication skills within the schemes rather than by volunteer involvement per se.

THE EVOLUTIONARY HISTORY OF MYCORRHIZAL SPECIFICITY AMONG LADY'S SLIPPER ORCHIDS

Abstract Although coevolution is acknowledged to occur in nature, coevolutionary patterns in symbioses not involving species-to-species relationships are poorly understood. Mycorrhizal plants are thought to be too generalist to coevolve with their symbiotic fungi; yet some plants, including some orchids, exhibit strikingly narrow mycorrhizal specificity. Here, we assess the evolutionary history of mycorrhizal specificity in the ladys slipper orchid genus, Cypripedium. We sampled 90 populations of 15 taxa across three continents, using DNA methods to identify fungal symbionts and quantify mycorrhizal specificity. We assessed phylogenetic relationships among sampled Cypripedium taxa, onto which we mapped mycorrhizal specificity. Cypripedium taxa associated almost exclusively with fungi within family Tulasnellaceae. Ancestral specificity appears to have been narrow, followed by a broadening after the divergence of C. debile. Specificity then narrowed, resulting in strikingly narrow specificity in most of the taxa in this study, with no taxon rewidening to the same extant as basal members of the genus. Sympatric taxa generally associated with different sets of fungi, and most clades of Cypripedium-mycorrhizal fungi were found throughout much of the northern hemisphere, suggesting that these evolutionary patterns in specificity are not the result of biogeographic lack of opportunity to associate with potential partners. Mycorrhizal specificity in genus Cypripedium appears to be an evolvable trait, and associations with particular fungi are phylogenetically conserved.

Mycorrhizal interactions of orchids colonizing Estonian mine tailings hills

Northeastern Estonia is home to extensive oil shale mines. Associated with these are desolate and environmentally damaging hills of ash and semicoke tailings. Interestingly, some of the first plants to colonize these hills are rare orchids. Here, we assess the identities of the mycorrhizal fungi associated with these orchids, in particular Epipactis atrorubens, Orchis militaris, and Dactylorhiza baltica, and compare them with mycorrhizal fungi from orchids from pristine habitat. Epipactis atrorubens associated with the widest breadth of fungi, including unnamed members of the basidiomycete family Tulasnellaceae and the potentially ectomycorrhizal ascomycetes Trichophaea woolhopeia and Geopora cooperi. Orchis militaris also associated with unnamed members of the Tulasnellaceae. Dactylorhiza baltica associated with Ceratobasidium albasitensis. In Epipactis and Orchis, the same fungi associated with plants in the pristine habitat as with those on ash hills. The tulasnelloid and ceratobasidioid fungi mycorrhizal with these orchids appear closely related to common orchid mycorrhizal fungi, while one of the ascomycetes mycorrhizal with E. atrorubens is closely related to a mycorrhizal fungus with E. microphylla. Our results suggest that these orchids and their fungi are not limited to pristine habitats and that environmentally polluted sites may present novel habitats that may be exploited for endangered plant conservation.

ADULT WHOLE-PLANT DORMANCY INDUCED BY STRESS IN LONG-LIVED ORCHIDS

Dormancy is a condition in which an herbaceous perennial does not sprout for one or more growing seasons. To test whether dormancy is an adaptive response to environmental stress, we defoliated and shaded individuals of two rare geophytic orchids, Cypripedium calceolus and Cephalanthera longifolia, in five Estonian populations early in the growing season in 2002 and 2003. We also censused plants at the same time, and conducted one more census in 2004. Mark–recapture models were used to estimate the probabilities of dormancy (d, the complement to resighting, p), and apparent survival (ϕ). Apparent survival varied little by treatment, with Cypripedium and Cephalanthera surviving at 0.986 ± 0.014 and 0.974 ± 0.021 (mean ± se), respectively. In contrast, treatment impacted dormancy dramatically. For both Cephalanthera and Cypripedium, defoliated (def.) plants were most dormant (0.320 ± 0.055 and 0.095 ± 0.036, respectively). However, while both control (cont.) and shaded (sh.) plants were roughly equally leas...

Habitat preferences as related to the prolonged dormancy of perennial herbs and ferns

Prolonged dormancy (hereafter dormancy), a phenomenon in which a perennial herbaceous plant does not sprout for one or more years, is examined. The phenomenon may be more frequent than stated so far and discovery of its role in plant life history and performance is still underway. Data from published papers was reviewed and all known species exhibiting dormancy were analysed from the aspect of species ecological values. Adaptation to environmental factors (light, moisture, pH and nitrogen as estimated by Ellenberg indicator values) influences the maximum duration of dormancy. A higher proportion of plants are dormant in species that prefer to grow in good light conditions, dry sites and infertile soil. The duration of dormant period is longer in species that prefer to grow in dry sites and/or calcareous soils. A range of factors, we believe, control plant behaviour, however, it is suggested that environmental stress is the principal factor inducing dormancy.

DEMOGRAPHIC RESPONSE TO SHADING AND DEFOLIATION IN TWO WOODLAND ORCHIDS

Many woodland herbs are long-lived, clonal geophytes that have evolved life histories favoring survival over reproduction. We examined the life history responses of natural populations of two woodland orchid species,Cypripedium calceolus andCephalanthera longifolia to defoliation and heavy shading conducted early in the growing seasons of 2002 and 2003. We asked whether, in view of the importance of growth for the survival of geophytes, treated plants were more likely to exhibit reduced flowering than reduced vegetative growth in the seasons following treatment. We also asked whether plants would suffer reduced ramet performance. Both treatments led to significant declines in flower number per ramet, number of leaves per ramet, and mean ramet height relative to controls inCypripedium. However, inCephalanthera, only shaded plants exhibited significant declines in flower number per ramet, and only defoliated plants exhibited declines in mean ramet height. The number of ramets per plant did not decline relative to controls in either species. Thus, these orchids, especiallyCypripedium, appeared to allocate resources preferentially to vegetative growth functions over sexual reproduction. Per-plant variation in leaf and flower number per ramet, as well as in mean ramet height, consistently declined in response to treatment, significantly so in the case of mean ramet height, suggesting that ramets became more similar within genets. These results suggest both similarities and differences in the ways in whichCephalanthera andCypripedium mobilize resources in response to stress.

Genetic variability, population size and reproduction potential in Ligularia sibirica (L.) populations in Estonia

Ligularia sibirica (L.) Cass. (Asteraceae) is a EU Habitats Directive Annex II plant species that has suffered a lot from human-caused major changes in quality and availability of habitats in Estonia. The aim of this study was to find out if the observed decline in population size is reflected in the amount of genetic variation and fertility in remnant populations of this species. AFLP technique was used for that purpose. Genetic diversity within populations was assessed as the percentage of polymorphic loci in a given population and average gene diversity over loci. The degree of genetic differentiation among populations and genetic differentiation between pairs of populations was estimated. The amount of viable seeds per flower stem was compared among populations and between years (2007 and 2008). Average genetic diversity over loci and proportion of polymorphic loci in L. sibirica populations were significantly correlated with population size, suggesting the action of genetic drift and/or inbreeding. No correlation was found between genetic and geographic distances. Natural barriers like forests may have been efficiently preventing seed migration even between geographically closer populations. Results of this study suggest that genetic erosion could be partially responsible for the lower fitness in smaller populations of this species.

Linking vegetative dormancy to fitness in two long‐lived herbaceous perennials

Vegetative dormancy occurs in many plant families, but its evolutionary context remains a mystery. We asked whether vegetative dormancy is an adaptive response to environmental stress and environmental stochasticity in certain long-lived plant species. We conducted an in situ experimental study in two and three populations of Cypripedium calceolus and Cephalanthera longifolia, respectively, in Estonia. Plants were defoliated, shaded, or simply observed at the beginning of the growing season in 2002 and 2003, and monitored demographically through 2008. We assessed links between fitness and vegetative dormancy using stochastic life table response experiments (SLTREs), in which the impact of treatment on the log stochastic population growth rate (a = log λS) via shifts in projection matrix transitions in treated plants relative to controls was used to assess the fitness impacts of treatment-induced life history responses. In Cypripedium, the observed lifespans of individuals that became vegetatively dormant in 2003/04 was significantly higher than plants that had not done so (P = 0.050). Defoliation and shading resulted in lower levels of flowering in both species. Both defoliation and shading decreased a relative to controls in Cypripedium and Cephalanthera. Defoliation- and shading-induced shifts in transitions involving vegetative dormancy were generally associated with significantly positive SLTRE contributions to Δa, and shifts in the standard deviations of demographic rates generally contributed little to Δa. Thus, vegetative dormancy is likely to be an adaptive response to environmental stress and stochasticity. Further work on the genetic basis to vegetative dormancy will clarify whether enough heritability may have existed in the past, or exists now, to support vegetative dormancy as an adaptation.

Factors influencing IUCN threat levels to orchids across Europe on the basis of national red lists.

Abstract The red list has become a ubiquitous tool in the conservation of species. We analyzed contemporary trends in the threat levels of European orchids, in total 166 species characterized in 27 national red lists, in relation to their reproductive biology and growth form, distribution area, and land cover where they occur. We found that species in central Europe are more threatened than those in the northern, southern, or Atlantic parts of Europe, while species were least threatened in southern Europe. Nectarless and tuberous species are significantly more threatened than nectariferous and rhizomatous taxa. Land cover (ratios of artificial land cover, area of pastures and grasslands, forests and inland wetlands) also significantly impacted the threat level. A bigger share of artificial land cover increases threat, and a bigger share of pasture and grassland lowers it. Unexpectedly, a bigger share of inland wetland area in a country increased threat level, which we believe may be due to the threatened nature of wetlands themselves relative to other natural land cover types. Finally, species occurring in multiple countries are on average less threatened. We believe that large‐scale analysis of current IUCN national red lists as based on their specific categories and criteria may particularly inform the development of coordinated regional or larger‐scale management strategies. In this case, we advocate for a coordinated EU protection and restoration strategy particularly aimed at central European orchids and those occurring in wetland area.

The impact of recent colonization on the genetic diversity and fine-scale genetic structure in Orchis militaris (L.)

Many terrestrial orchid species have undergone a serious decline in their ranges in Estonia and in other countries, mainly due to land-use changes. Some species have found a suitable habitat in anthropogenically disturbed areas, such as abandoned quarries and gravel pits. Using AFLP, we studied genetic variation and its structuring on a fine scale in three recently established and three old populations of Orchis militaris (L.) in Estonia. Our aims were to determine whether the colonization process resulted in a decline of genetic variation due to a created bottleneck or an increased spatial structuring due to seedling establishment around maternal plants. To evaluate plant reproductive success, the fruit set and the proportion of seeds containing embryos were measured. Our results revealed that O. militaris maintained high levels of genetic variation in recently colonized areas, even outside of the main distribution area, with a limited number of potential source populations. Similarly, no differences in reproductive success were observed between old and recently established populations. The extent of fine-scale genetic structure showed substantial variation: significant spatial structure was detected in all of the recently established populations and in one mature mainland population, whereas very weak genetic structuring on a fine scale was detected in two old populations in the main distribution area. Our results suggest that the conservation of recently established populations in anthropogenic areas should be considered in addition to the protection of indigenous calcareous grasslands to prevent the further decline of this species in Estonia.