Metapopulation Research Group
University of Helsinki Annual Report 2001
Metapopulation Research Group
Department of Ecology and Systematics
University of Helsinki
Edited by Tapio Gustafsson E-mail and web sites
To contact us via E-mail use [email protected]
Metapopulation Research Group (UH), http://www.helsinki.fi/science/metapop/
Biodiversity in Boreal Forests (FIBRE), http://www.helsinki.fi/science/biobof/
Survival of Species in Fragmented Landscapes (EC´s TMR-Network), http://www.helsinki.fi/science/fragland/
MRG-logo designed by Gergely Várkonyi
2 Contents
Preface 5
Brief history and overview of the MRG 6
Scientific highlights of 2001 9
Structure of the MRG 19
MRG personnel and their research interests 23
Laboratory facilities 48 Helsinki Tvärminne Lammi
Field sites 50 Åland Islands Kuhmo Central Finland Lammi Kilpisjärvi Greenland
Synopsis of the year 2001 56 Budget Publications Theses External visits Seminars, lectures and talks TV, radio and newspapers Teaching and courses Honors and awards Council memberships Meetings organized by the MRG Visitors to the MRG
Prospects for the year 2002 72
3 A mating pair of the Glanville fritillary butterfly (Melitaea cinxia) in the Åland Islands. Photo Tapio Gustafsson.
Occupied (filled) and empty (open) habitat patches suitable for the Glanville fritillary in the Åland Islands in the autumn 2001.
4 Preface
The year 2001 was punctuated by bursts of activity in the MRG. In January, we welcomed Toshka as our new technician in the molecular laboratory, Alia in the ranks of graduate students, and Ax and Marc amongst the post docs. Oscar arrived as a senior researcher in July, increasing the current number of nationalities and continents represented in the MRG to 10 and 4, respectively. MRG must be the most international research group in the University of Helsinki! In March-April, many of us attended three meetings in a row, including the annual Fragland meeting in Leeds, the Spring Symposium of the graduate students at our own department (organized this year by Anna-Liisa, Mar and Janne), and the annual MRG meeting, which took us to Saaremaa in Estonia (thanks to Tonu Talvi for helping to organize this meeting). The field season was particularly busy this year, including the new shrew project in eastern Finland (Ax and two amazingly exuberant field assistants, Anna and Kaisa), a butterfly experiment in Lammi (which was largely a failure, mostly because of exceptionally bad weather in June), the usual amount of cinxia work in Åland (p. xx) and two short trips to the steppes and boreal forests in South Urals (p. xx). A busy field season was followed by a busy conference season, with MRG presence in meetings from Hawaii and Australia to North America and closer to home in Europe. The autumn started off with a 3-day working meeting with Paul Ehrlich, Carol Boggs and Jessica Hellmann from Stanford, with whom several of us are writing a book on checkerspot population biology. The plan is to merge our model system Melitaea cinxia in Åland with Ehrlich's model system of Euphydryas editha in California to an even more comprehensive population biological model system of checkerspot butterflies. The MRG is not only bigger today than ever but it also functions better than ever. We still have a deficit of senior researchers even after Oscar joined us in July, which means that not every student and pos doc has received the just amount of attention. But we have identified the problem, we have discussed the problem, some progress has been made towards solving the problem, and we have means of making even more progress on this issue in the coming year. We have an exceptional set of post docs who have brought a huge amount of expertise to benefit the entire MRG. Last year's baby boom (4) was not quite repeated this year, but congratulations go to Tapio and Riitta (boy) and to Ax and Julie (boy). Last but not least, my thanks and the thanks of all of us to Anu and Tapio for yet another year in the MRG.
Ilkka Hanski
5 Brief history and overview of the MRG
Professor Ilkka Hanski has worked on spatially structured populations since the late 1970's. The early work dealt primarily with small-scale spatial population structure, but since the early 1980's the focus shifted to larger spatial scales and to metapopulation dynamics in the sense of assemblages of discrete local populations connected by migration. In 1989, Hanski organized the first international meeting on metapopulation dynamics together with Professor Michael Gilpin (San Diego, UC), which resulted in the first edited volume on the subject (Gilpin & Hanski, 1991, Metapopulation Dynamics: Empirical and Theoretical Investigations, Academic Press, London). This meeting furnished impetus for the conception of the MRG. Ongoing collaboration with Professor Mats Gyllenberg (Department of Mathematics, Turku, Finland) started in 1990, the long-term field project on the Glanville fritillary butterfly was started in 1991, and the first post graduate students and post docs were accepted in the MRG in 1992 and 1993, respectively. Oscar Gaggiotti joined the MRG as a senior researcher in 2001, bringing his expertise in theoretical population genetics and his perspective to spatially structured populations.
The figure below illustrates the growth of the MRG since 1992:
Currently there are 13 post graduate students, 10 post docs and 2 senior researchers in the MRG representing 10 different nationalities from 4 continents. The technical staff includes 5 persons.
6 The MRG consists of three research teams with an experienced post doc as a team leader (Metapopulation Modelling Team [Atte Moilanen], The Glanville fritillary Team [Marko Nieminen] and the Molecular Ecology Team [Jodie Painter]) and three projects of fixed duration (Old-growth forest biodiversity, small mammal population dynamics, and forest canopy insect dynamics). Additionally, the MRG (Hanski) coordinates an European Commission-funded training network (Fragland) in the TMR programme (4th Framework Programme). A more detailed description of the structure of the MRG is presented on page XX.
Academic setting
The MRG is the largest research group in the Division of Population Biology (DPB), Department of Ecology and Systematics, at the University of Helsinki. The permanent staff of the DPB consists of 3 professors and 9 other academic staff. Despite its small size the DPB with several active research groups and researchers has performed well in recent years. The MRG has had an influence on the general direction of research in the DPB, which is now to a large extent focused on spatial ecology, of which metapopulation ecology represents a key area. The DPB established a joint research programme called Spatial Ecology in 1997 (see www.helsinki.fi/ml/ekol/spatial_ecology.html).
Scientific standing
The MRG has established a solid reputation as one of the leading research groups internationally in metapopulation ecology. The two most visible achievements of the MRG are the development of effective modelling approaches to the dynamics of metapopulations living in highly fragmented landscapes and a large-scale empirical research project on the Glanville fritillary butterfly (Melitaea cinxia). The latter started as an ecological project but has by now expanded to cover metapopulation genetics and evolutionary biology as well. This field project, which is well known internationally, allows us to test many theoretical predictions and it hence functions as an important interface between theory and empirical research.
7 Strategic goals of the Metapopulation Research Group
· To strengthen our position as the leading research group in metapopulation biology worldwide
· To build up on our current strength in combining modelling with empirical studies
· To integrate genetic and evolutionary studies into the existing strong ecological framework and thereby to promote a comprehensive approach to metapopulation biology
· To facilitate the application of metapopulation biology in landscape-level environmental planning and management and conservation of populations.
Female Melitaea cinxia laying her eggs on Plantago leaf. Photo Tapio Gustafsson.
8 Scientific highlights of 2001
Melitaea cinxia project in Åland
Year 2001 was the tenth year of research on Melitaea cinxia in Åland Islands. It was also the eighth year of monitoring the status of all habitat patches known from Åland, and M. cinxia’s occupancy and population sizes in them. The preliminary results from this year’s monitoring from the end of August to mid-September show that M. cinxia has done well in most regions within Åland. In those regions, it has colonised approximately three times as many patches as there were extinctions of local populations this summer. On the other hand, the largest populations were considerably smaller than last year, even though population sizes were larger in general. Of the core areas of existence, only in the westernmost part of Åland (Eckerö) extinctions exceeded colonizations and population sizes decreased on average. The reexamination of the habitat patch network in Åland that was started in 1998 was completed in 2001. In this work, we have critically reviewed the limits of each habitat patch which is in principle suitable for Melitaea cinxia’s reproduction and therefore has to include resources for larvae (host plants). During the process, each of the ca 4000 patches has been mapped by a GPS which records submeter-accurate coordinates of the patch boundary every three seconds. When transformed into a GIS and plotted on basic maps these data can be used for various spatially accurate analyses and modelling. We also performed pilot work on GPS-aided study on movements of butterflies. In this work, we released butterflies in different types of non-habitat and followed them as long as they either disappeared or found a habitat patch. Each stopping point and time were recorded with a GPS. Preliminary results show for example that they can detect a patch that is topographically somewhat higher in the landscape than the non-habitat where the butterflies were released from ca 20- m distance. However, due to difficult weather conditions during the study, sample size is not large enough yet to draw firm conclusions and this study will be continued in 2002.
Combining ecological and genetic data in order to make inferences about colonisation patterns in a metapopulation, by Oscar Gaggiotti
I have joined the Metapopulation Research Group very recently and look forwards to contributing towards the strengthening of the population genetics aspects of the research being carried out within the group. The MRG provides an ideal setting for carrying out my research, which is aimed at bridging the gap between the fields of ecology and population genetics/evolution. One of the strengths of the group is its
9 current focus on a model system, the fritillary butterfly Melitaea cinxia. This type of approach in which all aspects of the biology of a given species are studied in a coordinated fashion can shed new light on the way in which ecological and genetic factors interact to determine the evolutionary potential of a species. Traditionally, the fields of evolution and population genetics have relied to a large extent on the use of mathematical models. Currently, attention is focused on the use of genetic data in order to estimate the parameters of population genetic models, in particular, effective population size, the age of an allele, migration rates, etc. Note, however, that we can go beyond the simple estimation of parameters and use multilocus genetic data to make inferences about the ecological factors that are controlling them. This is a much more difficult task but recent developments in the fields of molecular biology and Bayesian statistics have provided us with the tools that allow us to achieve this goal. One of the highlights of my research deals with this problem. During the last couple of years I have concentrated my attention on the study of the patterns of colonisation in a metapopulation of British grey seals. This species has been studied extensively and we have the time series of pup production estimates for the last four decades. This time series indicates that the British grey seal population has been growing at 6% per year over the last few decades and that this growth involves the founding of new breeding colonies. The colonisation of new habitat is a fundamental process in metapopulation biology, but is difficult to study. In the case of the grey seal it was important to investigate the role played by local population density and geographic distance in the founding of new breeding colonies. Thus, we collected genetic samples and obtained microsatellite markers from three recently founded colonies and seven potential source populations. I developed a Bayesian/McMC approach that combines multilocus genetic data with demographic and geographic distance data and uses a likelihood function that generalises the genetic stock identification method (GSI). The parameters of interest are the proportionate contribution, xi, of each source to the founding groups, x = {xi}. Two further ecological parameters (R and S) specify the contribution of density-dependent effects and of geographic distance to the probability distribution for x. The analysis showed that, in all three colonisation events, there are large variations in the estimated proportion of colonists from different putative sources, with the two most important sources contributing 43%-59%. Both geographic distances between sources and new colonies and demographic factors (size and dynamics of source populations) had an effect. The relative importance of distance and productivity in each of the colonisation events appears to have been determined by the location of potential sources around the vacant site. For an isolated population, which was more or less equidistant from all sources, the effect of density was the main factor controlling the formation of the propagules. For a
10 colony that was close to many source populations, geographic distance was more important. The last new colony, also the northernmost one, is relatively close to the most productive source populations. In this last case, both density and geographic distance played a role in the formation of colonising groups. The figure below shows this last case. The green triangle identifies the newly founded colony while the two red dots identify the two main contributing source populations. This is the first study that combines genetic, demographic, and geographic distance data in order to make inferences about ecological factors. This method will prove useful for many other species, including those studied by the MRG.
0.3
0.25 FA HS 0.2
E(x) 0.15 i HH MG 0.1 SW RU
0.05 ST
0 0 0.1 0.2 0.3 productivity
0.3
0.25 FA HS 0.2
0.15 E(xi) HH MG 0.1 RU SW Orkney 0.05 ST Islands 0 0 20 40 60 80 distance
Uniting deterministic and stochastic metapopulation models, by Otso Ovaskainen
In the years 1999-2000, my main contribution to developing metapopulation theory was to show that the dynamic behaviour of many spatially realistic metapopulation models (which can be applied to real patch networks with variation in patch area and connectivity) may be captured by simple 1-dimensional models with appropriately transformed parameter values. The result is nice in the sense that it allows theory developed for simple and mathematically tractable models to be applied in a spatially realistic setting. However, there is a caveat, which is that the theory is restricted to deterministic models. As stochastic fluctuations often play a major role, stochastic patch occupancy models (SPOMs) should be used instead of deterministic models.
11 In the year 2001 I concentrated in the analysis of SPOMs. As mentioned, SPOMs are more realistic than their deterministic counterparts (which should be considered as mean-field approximations of the full SPOMs), as they are able to account for the stochastic fluctuations in patch occupancy. Unfortunately, the quantitative analysis of SPOMs is difficult, as the computational effort needed to determine the long-term behaviour of a SPOM grows as a power of 2n, where n is the number of habitat patches. Consequently, large systems have so far been analyzed only through simulation studies. I developed a computationally feasible approximation method, which approximates the behaviour of a SPOM by an 'ideal' metapopulation inhabiting a network of identical and equally connected habitat patches. Conseptually, the method resembles the calculation of the effective size of a population in the context of population genetics. The transformation to the ideal metapopulation is based on weighting the individual patch occupancies by the dynamic values of the habitat patches, which may be calculated from the deterministic mean-field approximation of the original SPOM. Thus, instead of considering just the fraction of occupied patches p, I considered a weighted fraction of occupied patches pl, the weights being the dynamical patch values. The figure illustrates the method applied to a network of 50 patches with considerable variation in patch area and connectivity. Panels a and b depict the infinitesimal mean and variance of pl, the dots corresponding to 300 randomly chosen occupancy patterns in the original network, and the lines corresponding to the ideal metapopulation. In this case, the ideal metapopulation consists of 43 patches, and thus the effective number of patches is somewhat smaller than their real number, the reason being that the smallest and most isolated patches contribute only a little to metapopulation dynamics. Panels c and d illustrate metapopulation dynamics as simulated for the original metapopulation (panel c) and for the ideal metapopulation (panel d).
Spatially realistic metapopulation theory: synthesis of the dynamic theory of island biogeography and the classic metapopulation theory, by Ilkka Hanski
12 Current interest in spatial ecology has several roots, of which the dynamic theory of island biogeography (DTIB), established by Robert MacArthur and Edward O. Wilson in the 1960s, is best known and has been most influential. The DTIB originally addressed patterns in the large-scale distribution of species on oceanic islands. The key innovation of MacArthur was to explain these patterns by the ecological processes of population extinction and population establishment. The primary pattern to be explained was the dissimilar number of species on different islands. By the late 1980s, interest in the DTIB was clearly declining both in ecology and in conservation biology, while a new paradigm of spatial ecology, the metapopulation theory, began to gain popularity. Like the DTIB, the metapopulation theory was based on a simple model, due to Richard Levins (1969), here referred to as the classical metapopulation theory (CMT). At hindsight, and especially in the context of applying the theory to conservation, the most restrictive simplifications of the DTIB were the assumption of a permanent pool of mainland populations, which is a poor metaphor for many increasingly fragmented terrestrial landscapes consisting of a network of small fragments (as assumed in the CMT), and the assumption, in the basic model, of identical species. On the other hand, an important limitation of the CMT is the assumption of identical habitat patches, which makes it difficult to apply this theory (unlike the DTIB) to real metapopulations. It is only recently that we have fully realized that a relatively simple general theory can be readily constructed that makes these simplifying assumptions unnecessary, and which in a very real sense represents a synthesis of the dynamic theory of island biogeography (MacAtrhur and Wilson 1967) and the classical metapopulation theory (Levins 1969). These ideas have been around in the MRG and elsewhere for several years, but it is worth underscoring the value of the "spatially realistic" metapopulation theory in terms of unifying the two previous and influential paradigms in spatial ecology. The essential difference between the DTIB and the CMT is the assumption in the former of a permanent "mainland" area with permanent "mainland populations" that generate a constant flux of migrating individuals to the archipelago of true or habitat islands. The DTIB is concerned with the number of species in island communities, while the CMT is focused on an individual species, but this is not a fundamental difference, because most applications of the DTIB assume ndependent species. Because of migration from the mainland populations, island populations will not go permanently extinct in the DTIB, though the equilibrium number of species present on any particular island varies depending on island size and isolation. In contrast, species may go permanently extinct in the CMT, and the theory predicts that they will do so when the amount of habitat (patches) in the landscape has been reduced below a threshold level.
13 In the DTIB, the dynamic variable is the number of species on a particular island (or habitat fragment) i, Si. The basic form of the MacArthur-Wilson (1967) model is captured in the differential equation, dSi /dt = c(R-Si ) - eSi , (1) where R is the total number of species in the mainland species pool and e and c are constant extinction and colonization rate parameters. In the CMT as formulated by Levins (1969), the dynamic variable is the number of habitat fragments occupied by the species, P, and the model is dP/dt = cP(T-P) - eP, (2) where T is the total number of fragments (assumed to be very large) and e and c are the extinction and colonization rate parameters. The two models are related because the expected number of independent species on a particular habitat fragment is given by the sum of the probabilities of different species occurring on that fragment. Let us hence construct a n- dimensional model with one equation for each habitat fragment giving the probability of that fragment being occupied (Hanski and Gyllenberg 1997; Hanski and Ovaskainen 2000), dpi /dt = [colonization rate]i (1- pi ) - [extinction rate]i pi . (3)
Assuming a mainland pool of R species as in the DTIB, and that the species are identical with independent dynamics, model (1) is obtained by multiplying both sides of Eq. (3) by R and assuming constant colonization and extinction rate parameters. Assuming a set of identical and equally connected habitat fragments as in the CMT, model (3) gives the rate of change in the probability of any patch being occupied as dp/dt = cp(1-p) - ec, which is also the rate of change in the fraction of occupied patches. Multiplying both sides of the equation by T and scaling parameter c by 1/T gives Eq. (2). Apart from uniting the two previous models, model (3) does more. For a set of n habitat fragments, model (3) consists of a set of n coupled equations (note that model [1] has also n equations for n islands, but these equations are not dynamically coupled). Therefore, the model retains information on the occurrence of the species on particular habitat fragments with particular spatial locations in the landscape.
14 Hanski, I. 2001. Spatially realistic theory of metapopulation ecology. Naturwissenschaften, in press.
Phylogeography of Pytho kolwensis, by Jodie Painter
Phylogeography is the study of the biogeography of a species by comparing a gene-based phylogeny with current and historical geographical distribution. P. kolwensis, an endangered boreal forest specialist beetle, lives exclusively on fallen Norway spruce (Picea abies) in old-growth spruce mires, and its presence indicates a high conservation value for a particular forest and the surrounding area. During the last glacial maxima, approximately 18 000 YBP, there were two main refugial areas for spruce, one around the bottom of the Ural mountain range in Russia, and another around north-eastern China. Following the retreat of the glacial ice, what has been the direction of movement of spruce associated species? To investigate this question I have generated DNA sequence data from a mtDNA gene (Cytochrome Oxidase I) for P. kolwensis samples collected from various localities in Sweden, Finland, Russia and China. For comparison two additional Pytho species have also been included, P. abieticola, another rare boreal forest dweller, and P. depressus, a common, pine associated species with a distribution extending into southern Europe. A striking feature of this study has been the low level of mtDNA variation found in P. kolwensis and P. abieticola, the boreal forest specialists. For both species most individuals share a common haplotype, with occasional individuals differing by one or two of 500 bases from the common sequence. This is most likely the result of population bottlenecks and founder events reducing genetic variation as these species reinvaded northern Europe and Asia following the retreat of glacial ice. Another feature is the distribution of haplotypes. All species have two haplotype lineages, one characteristic of western boreal forests (Sweden, Finland, western Russia and Lake Baikal), and an eastern group found exclusively in China. Interestingly, for P. kolwensis and P. depressus, the western boreal haplotype is also found in small numbers in China (only 5 individuals of P. abieticola were sampled here). In both P. kolwensis and P. depressus there are more sequence differences amongst the eastern haplotypes, suggesting that these haplotype lineages are older than the western boreal lineages. Focussing particularly on P. kolwensis, using a mtDNA divergence rate of 2% per million years suggests a split between the western boreal and eastern lineages sometime during the early to middle Pleistocene, some considerable time prior to the last glacial period. The western boreal haplotypes in China include the commonly shared haplotype, haplotypes with one or two changes from the common haplotype and also the most divergent haplotypes (up to 6 changes) in this group. Perhaps the
15 invasion of P. kolwensis into China has been occurring during interglacials including and previous to the one we are presently enjoying.
Haplotype distribution of Pytho kolwensis
Glacial ice
Spruce refugial areas
Western boreal haplotype lineage. The filled in circle is the common haplotype
Eastern haplotype lineage. The filled in square is the common haplotype
Site selection work, by Atte Moilanen and Mar Cabeza
Methods for designing reserve networks mostly concentrate on providing maximal representation of species with the minimum cost. Representation-based approaches, however, typically consider a static snapshot of species incidences, and the spatial dynamics of the species are ignored.
16 By using a model of spatiotemporal dynamics to assess the persistence of biodiversity in reserves selected by common methods, we have recently shown how badly current site-selection methods may perform in terms of species persistence, especially in the presence of habitat loss (see figure). We looked at the species extinctions in the selected reserves in two situations: first, when all sites were included in the simulation (white dots), and second, when the non-selected-sites were excluded (i.e. assumed to be destroyed if they do not become a reserve-black dots). We found that common site-selection algorithms do not perform well in the long term, and they perform even worse if the habitat around the reserves is lost. Some important messages come from this exercise: (1) Algorithms that concentrate on efficiency (i.e. finding minimum set solutions) without including criteria for persistence may be the less effective ones in the long-term. This is because these algorithms tend to select the smallest possible number of sites and the smallest in size. However, the more sites and the larger the sites, the better biodiversity persists. Also, considering more species in the reserves’ selection process improves the performance of the algorithms (In the figure, square: 400spp; triangle: 200spp; circle: 100spp), because more area is needed to represent more species. (2) Habitat outside the reserve networks might be more important for the persistence of biodiversity in the reserves than the reserves themselves. For instance, if we are protecting sinks instead of sources, the species may persist in the reserve as long as the source exist, but if the source suffers from habitat loss, there is no guarantee of the persistence of the species in the protected sink site. This exercise has served to show the urgent need to incorporate spatiotemporal dynamics into methods for site-selection.
Two trips to South Urals, by Ilkka Hanski
Following the field work in boreal forests in NE China in 2000, and especially the results concerning Pytho kolwensis (p. xx), the idea arouse in early 2001 of visiting the other important glacial refuge of the Norway spruce in the palaearctic region apart from NE China: the southern end of the Ural mountains. An additional attraction of this region is that spruce forest on mountains is located close to steppes - the habitat of the Glanville fritillary and many other checkerspot
17 butterflies. Two short trips were organized. Jaakko Kullberg from the Natural History Museum in Helsinki and Marcin Zalewski from Warsaw in Poland made a 2-wk exploratory trip to the area in June, while Saskya van Nouhuys and Ilkka Hanski visited the steppes in the Orenburg region and Juha Siitonen (Finnish Forest Research Institute) and Yu-cheng Dai (Natural History Museum in Helsinki) visited the spruce forests in Bashkiria in August. Visits to the spruce forest produced no Pytho kolwensis in June nor in August. It is apparent that the species doesn't occur as far south as the Iremel mountain in Bashkiria, though the two congenerers P. abieticola and P. depressus were sampled in large numbers. The spruce forest is there, but the forest structure was not quite what it was expected to be, for instance the amount of dead downwood was suprisingly small. Possible explanations include human influence in the past, extensive forest fires, unproductive soils, and altitude. Nonetheless, good samples of P. abieticola and P. depressus were obtained and we now know that P. kolwensis has to be searched from localities further north.
South Ural steppes - the habitat of the Glanville fritillary and other checkerspot butterflies. Photo Ilkka Hanski.
The visits to the steppes were not completely successful either. We found the Glanville fritillary, the species we most wanted to find, but only in very small numbers, and the plan to sample the populations for parasitoids failed. Several other species were also sampled, but only one species in large numbers. Initially, we expected that the checkerspots would have large continuous populations in the
18 steppes in South Urals, which would provide an interesting contrast to the highly fragmented landscape in the Åland Islands. It now appears that the landscape in South Urals is effectively highly fragmented for checkerspots, because larval host plants are likely to wither during the warm and dry summer (or don't exist at all) in large parts of the landscape. The most favourable sites are north-facing hill sides. On the positive side, the sample of the Glanville fritillary that we have will be enough to study the host plant preference of females, about which nothing is known for Asian populations. The larvae were found on Veronica incana (a close relative of V. spicata). It will be interesting to see how strongly females prefer V. incana to Plantago lanceolata, which is common in the area though has a substantially different growth form from the Finnish populations.
Steppes at the sunset. Photo Ilkka Hanski.
Research on the parasitoids of the Glanville fritillary, by Saskya van Nouhuys
The Glanville fritillary butterfly is host to two primary parasitoids and several hyperparasitoids in the Åland islands. These parasitoids have significant ecological impact on one another and on the butterfly. As we learn more about their natural history and behavior our research on the population dynamics of interacting species in a fragmented landscape is becoming increasingly exciting.
19 One of the most interesting aspects of our current research is the comparison of dispersal behaviors of the Glanville fritillary butterfly and its two specialist primary parasitoids in a fragmented landscape. Early in the year Ilkka Hanski and I used data from experiments and long term field surveys to show that the ability of the butterfly to colonize new populations is intermediate between that of the two parasitoids. One parasitoid, Hyposoter horticola disperses broadly so it experiences the host butterfly in Åland as one big patchy host population. In contrast, the second parasitoid, Cotesia melitaearum, is limited by dispersal and therefore only occupies tightly clustered host population networks. During the summer of 2001 a student and I learned more about the behavior of the extremely mobile parasitoid H. horticola. We used observation of marked individuals and a field experiment to show that individual wasps forage for hosts for several weeks, move readily between host populations, and surprisingly, they appear to remember the spatial locations of host butterfly egg clusters.
Spatial dynamics of periodic Xestia moths with a two-year life cycle (Lepidoptera: Noctuidae), by Gergely Várkonyi
In 2001, we continued both empirical and – especially – modelling work with Xestia owlet moths that exhibit a striking alternate-year occurrence in boreal forests around the Northern Hemisphere (see AR 1999, 2000). At any one locality, there are two coexisting cohorts of these species in opposite phases of their fixed 2- yr developmental cycle. Those temporally isolated cohorts are typically rather inequal in their abundance, which leads to the striking alternate-year occurrence. A simple host-parasitoid model has been developed to explain the abundance difference between the syntopic moth cohorts. According to the model, a parasitoid with one-year development switches between the Xestia cohorts and hence regulates the rare host cohort. Modelling results are highly consistent with biological and numerical evidence obtained from field studies and from analysis of
20 long-term time series of both the host and a parasitoid wasp (Várkonyi et al., manuscript). Periodic occurrence of Xestia moths has been documented for more than a century now. There are two further conspicuous features in their population dynamics. First, in areas where periodic Xestia species are abundant, congeneric species have common flight years. Second, localities tend to form very large continuous in-phase domains of flight year pattern. In other words, dynamics of Xestia are typically in both interspecific and in spatial synchrony through time. In 2001, we developed a spatially extended version of the basic model and related the modelling results to empirical observations (Rost et al. 2001). A spatially extended model may have domains oscillating in opposite phases as it is the case between eastern and western Finnish Lapland. Spatial heterogeneity, such as varying carrying capacity of Xestia in space and/or in time, tends to fix the location of phase boundaries. Low carrying capacity in central Finnish Lapland, due to extensive wetlands and lakes in the region, is a plausible explanation for the probably rather stable domain boundaries in northern Finland. In contrast, spatially homogenous temporal fluctuations would tend to synchronize populations over large regions, i.e. we would expect to see large-scale switches from odd-year cohort dominance to even-year cohort dominance and vice versa. We are not aware of such switches, but one must recognize that empirical data from large areas covers only a relatively short period.
The macroecology of European carabid beetles, by Bob O’Hara
Macroecologists are interested in ecological patterns that are observed over large scales. One such relationship is that between the range of a species, and the average abundance. It is usually observed that more widespread species (i.e. with a larger range) are also more abundant. Several mechanisms have been put forward to explain this relationship, but none has yet won unequivocal support. Johan Kotze (also of the Dept. of Ecology and Systematics) has collated data from carabid beetle distribution atlases for Holland, Belgium and Denmark, and the relationship between abundance and range size is positive (see figure). We have been using this data, and other data on the
21 characteristics of the species, to test four of the proposed (but not, alas, the metapopulation hypothesis). We were able to reject the hypothesis that the relationship is an artifact due to incomplete sampling. Corrected abundances and range sizes were estimated under different hypotheses about the probability distribution of the recorded abundances. The different models gave similar estimates for the relationship between abundance and range size, hence the relationship was still present. We were also able to reject the hypotheses that the relationship was caused some of the species being at the edge of their range in the country investigated (the argument is that at the edges of a species range, it is in more marginal habitat, and hence has a lower abundance), and that the relationship is a result of phylogenetic dependence (for example, if one genus is both widespread and common, then this could create the relationship) by showing that the relationship still existed even when these factors had been taken into account. The one hypothesis that did seem to account for the relationship was the resource breadth hypothesis. This postulates that as generalist species are able to use a larger fraction of the habitat, they will have a larger range size, and a larger average abundance within that range. We were able to show that this is indeed the case for carabids in the three countries. As an added bonus, we also discovered that large species tend to be more widespread, and also that dimorphic species capable of having either long or short winged individuals are more widespread and abundant. In order not to appear as one-hit wonders, we have used data on the rates of decline of the different species, and correlated these to the characteristics of the species. We have found that larger species tend to have declined more quickly, as have specialists. Neither of these results appear surprising – larger species tend to have lower reproductive output and smaller powers of dispersal (and so are less able to track habitat changes), and specialists have less choices of alternative niches when their present habitat is destroyed to make way for a new bypass. More intriguingly, dimorphic species are declining less than either short or long winged species, despite our a priori expectation that long winged species would survive better, as they would be better able to track environmental changes. Our explanation is that this advantage is offset by the energetic requirements of growing wings and flight muscles, and that the dimorphic species are able to gain the best of both worlds.
22 Structure of the MRG
The diagram below illustrates the structure of the MRG and how the different teams and current projects relate to each other. Ilkka Hanski Tapio Gustafsson Anu Väisänen
The core MRG Melitaea cinxiaTeam Marko Nieminen Saskya van Nouhuys Sari Haikola Anna-Liisa Laine Juha Pöyry Mika Siljander Riitta Rantala Metapopulation Molecular Modelling Team Ecology Team Oscar Gaggiotti Atte Moilanen Jodie Painter Marc Bélisle Maaria Kankare Otso Ovaskainen Alia Sarhan Mar Cabeza Toshka Nyman
Boreal Forest Biodiversity Project Ilkka Hanski Leena Suvanto Laura Kivistö Reijo Penttilä Tarja Salmi Gergely Várkonyi
Tree Canopy Small Mammal Project Insects Project Ilkka Hanski Ilkka Hanski Pierre-Alexandre Landry Tomas Roslin Olivier Gilg Paavo Hellstedt Janne Sundell
TMR Network Fragland * Ilkka Hanski Bob O´Hara
23 * TMR Network Fragland, the PI`s
Ilkka Hanski, co-ordinator (Helsinki, Finland) Michel Baguette (Louvain, Belgium) Paul Brakefield (Leiden, Netherlands) Diego Jordano (Cordoba, Spain) Isabelle Olivieri (Montpellier, France) Christian Thomas (Leeds, United Kingdom) Christian Wissel (Leipzig, Germany)
Melitaea cinxia team
The large-scale and long-term metapopulation study of the Glanville fritillary butterfly (Melitaea cinxia) in the Åland Islands in SW Finland comprises the largest project in the MRG, combining extensive monitoring of hundreds of dynamically coupled local populations, intensive observational and experimental studies as well as active development of relevant theory and modelling approaches. The Glanville fritillary metapopulation in Åland functions as a model system with which we study ecological, genetic and evolutionary questions related to habitat fragmentation and to the biology of species living in fragmented landscapes. The project has produced several PhD and MSc theses and a large number of publications in top international journals, including Nature and Science.
Metapopulation Modelling Team
The research in the Metapopulation Modelling Team has been focused on ecological models of metapopulation dynamics, including both models that can be analysed mathematically and models that can be parameterized with empirical data. Of the latter, much work has been done on the Incidence Function Model, which was originally developed in parallel with the empirical study of the Glanville fritillary metapopulation in the Åland Islands. More recently, we have incorporated genetic and evolutionary components into our models, and this trend will be strengthened in the future. Substantial work has been done on reserve site selection algorithms, in particular towards the goal of incorporating spatial dynamics into the site selection algorithms.
Molecular Ecology Team
The research conducted in the Molecular Ecology Team is typically closely related to ongoing ecological projects in the MRG. Initially, the primary focus was the
24 Glanville fritillary butterfly, but over the past 5 years several other taxa have been studied as well, including other checkerspot butterflies (phylogenetic and phylogeographic studies), parasitoid wasps (phylogeny and spatial genetic structure), dung beetles (spatial genetic structure), old-growth forest specialist insect species (factors influencing genetic diversity), the flying squirrel (breeding system), and the aspen tree (clonal structure in natural and managed forests).
Forest Biodiversity Project
This project is funded by the Finnish Biodiversity Research Programme (FIBRE), and has a 6-yr duration (1997-2002). Our general aim is to increase the population biological knowledge of old-growth forest specialist taxa, including mammals (the flying squirrel), birds, insects, fungi and lichens. Particular projects have investigated the persistence of species in isolated fragments of old-growth forest, the spatial population structure and dynamics of aspen-associated specialist species, spore dispersal of fungi, and the use of corridors by the flying squirrel and moths. In 2000 and 2001 we extended the field studies to boreal forests in NE China and South Urals in Russia, the two main glacial refugia in the Palearctic region for the Norway spruce.
Small Mammal Project
This project addresses the role of small mustelid predators (the least weasel and the stoat) in the maintenance of the regular multi-annual population cycle of voles in northern Fennoscandia. Theoretical studies have demonstrated that the predator- prey interaction may drive the vole cycle and that generalist predators may have a strong stabilizing influence on vole dynamics. Empirical work has included a large-scale experiment, in which captive-born least weasels were released on experimental islands in lakes to eliminate the numerical response in weasels' population dynamics. Another field project investigates the cyclic populations of the collared lemming in eastern Greenland.
Tree Canopy Insect Project
This small project is focused on the spatial structure and dynamics of insect populations living in tree canopies. The field studies were started in 2000 on selected taxa feeding on oak, which has a highly fragmented distribution in Finland and which often occurs in small groups of trees or as single isolated trees.
TMR network Fragland
25 This is a training network funded by the European Commission in the Training and Mobility of Researchers (TMR) Programme. The project has a 4-yr duration, and will be completed in April 2002. Specific research tasks include a comparative study of 4 species of butterflies in the central and marginal parts of their geographic ranges in Europe, modelling of metapopulations in fragmented landscapes, inbreeding and other genetic consequences of habitat fragmentation, evolution of dispersal rate and other life-history traits in metapopulations, and an improved framework for conservation of species in highly fragmented landscapes.
Larvae of Melitaea cinxia inside their winter nest. Photo Tapio Gustafsson.
26 MRG personnel and their research interests
Marc Bélisle, Post doc
I joined the Metapopulation Research Group as a postdoctoral fellow in January 2001. I am interested in everything that influence the spatial distribution of animals, especially through foraging and movement, and this, across spatial scales ranging from the food item to the landscape level. My role in the research group lies mainly between trying to give sound statistical advice to students and developing simulation models that would help us predict the dispersal behaviour of forest birds in fragmented landscapes.
My main project consists in implementing empirical, gap-crossing decision rules of forest birds into a spatially-explicit, individually-based model. This model will be used (1) to quantify the functional connectivity of real landscape sections and see how it relates to landscape composition and configuration, (2) to calculate emigration and immigration rates among habitat patches, which will then be used to predict the population persistence of bird species inhabiting boreal, old-growth forests with the Incidence Function Model, and (3) to assess the influence of travel cost on the selection of territories by dispersing forest birds. By incorporating some behavioural ecology into simulation models, we hope to contribute to a better management of boreal forests. Note that this model is being developed in collaboration with Andrew Fall from the School of Resource and Environmental Management, Simon Fraser University, Canada. Fourteen territorial, mated male Yellow-rumped Warblers (Dendroica coronata) were translocated (2.1 km) within the Bow Valley of Banff National Park, Canada. Five potential barriers to forest bird movement run parallel to one another along the bottom of the valley: a 4-lane highway (width » 60-100 m), a river (width » 40-60 m), a railway (width » 20-30 m), a utility line (width » 20 m), and a 2-lane, secondary road (width » 20 m). Despite the small width of these open areas, the 7 warblers translocated across the valley (squares), such that they would face the barriers, took more time to return to their territories than the 7 warblers translocated along the valley (circles) and the barriers.
27 The amount of forest cover (ca. 38%) did not vary across treatments. See Bélisle and St. Clair in press. Mar Cabeza, Post graduate student
My research interests are population biology and spatial ecology. For my Ph.D. project I focus especially on conservation issues such as the design of nature reserves. During the last decades, systematic methods (site-selection algorithms) to select networks of reserves have been developed. So far, the current methods focus mainly on representation of biodiversity, but they ignore how well biodiversity persists once the reserve network is established.
During the past year, together with Atte Moilanen, I developed an approach to show how badly current site-selection algorithms may perform in the long term, especially when habitat loss occurs around the selected reserves. We used a model of spatiotemporal dynamics to assess persistence of species in the network of reserves selected by common algorithms. Some important messages come from this exercise: (1) Algorithms that concentrate on efficiency (i.e. finding minimum set solutions) without including criteria for persistence may be the less effective ones in the long-term. (2) Habitat outside the reserve networks might be more important for the persistence of biodiversity in the reserves than the reserves themselves. This has served to show the urgent need to incorporate spatiotemporal dynamics into methods for site-selection. Currently I’m concentrating on the development of such methods, and comparing them with other approaches that take persistence into account by means of selecting the sites were species have highest probability of occurrence.
28 Oscar Gaggiotti, Senior scientist My research interests cover a broad range of areas that include ecology, population genetics, evolution, and conservation biology. Its main objective is to bridge the gap between population genetics and population ecology by extending existing evolutionary and population genetics theory to include more realistic ecological scenarios. The objective of this research is two-fold. Firstly, to understand the evolutionary processes that lead to the patterns of biodiversity observed in natural ecosystems. Secondly, to provide the information needed for the design of management strategies that will maximise the amount of genetic variability maintained by populations that are affected by ever increasing human disturbances. My current research includes the development of metapopulation genetics/evolution models and Bayesian statistical approaches to make inferences about demographic processes in metapopulations. Currently I am studying the consequences that landscape fragmentation has on the genetic integrity of a species and their evolutionary potential using source-sink metapopulation models. I am also studying the effect of age- and stage-structure on the level of genetic variability maintained by a metapopulation. In the area of statistical genetics I am interested in developing new approaches that use multilocus genotype information in order to make inferences about dispersal processes in a metapopulation. The idea is to go beyond the simple estimation of dispersal parameters and try to determine the factors that motivate individuals to emigrate and colonise new habitat. In this regard, I have recently developed a Bayesian method that allowed me to evaluate the relative importance of density- dependent effects and geographic distance as factors involved in the founding of new colonies in a metapopulation of grey seals. I plan to extend this method to include other factors that may be involved in emigration and colonisation events in other species.
29 Olivier Gilg, Post graduate student
After my MSc thesis at the University of Aix-Marseille (France), where I developed a naturalness assessment method for old growth and managed forests, I worked for several years in a conservation agency. In 1998 I started my PhD project on the lemming cycle and predator-prey interactions. Several recent studies have converged to the conclusion that the periodic rodent oscillations in boreal and arctic regions are essentially maintained by the interactions between the rodents and their mustelid predators. However, before arriving at a definite conclusion for the 70-yr-old puzzle of rodent dynamics, several hypotheses need to be tested, combining appropriate empirical and theoretical approaches. For this purpose, I’m adapting and testing the empirically-based models developed by Hanski and co- workers during the past ten years on a simple and well-documented high arctic vertebrate community from Northeast Greenland. An ongoing collaborative effort between the Universities of Helsinki, Montpellier and Freiburg was initiated in 1998 in order to collect information needed to parameterize the model.
After a peak year in 1998 and an intermediate year in 1999, the lemming density (in 2000) was at its lowest level since 1988. Lemming densities are always relatively low in this high arctic community (max. 10 per ha), and are systematically declining over the summer season when nomadic (snowy owl) and migratory (long-tailed skua) predators join the resident mammalian carnivores (arctic fox and stoat). We already knew that the cycle length was 4 years, but regular trapping was done to access its amplitude. There was at least a 100-fold decrease between the highest (spring 1998) and lowest (fall 2000) densities. Most of the summer decline was due to predation (the only cause of mortality recorded for 38 radio-collared lemmings). The daily predation rate estimated from the radio- collared animals was very high in 1998 and 1999 (respectively 3,5 and 2%) and can, alone, explain the sharp summer decline recorded from trapping. Densities, reproductive success and functional responses of the predators were also investigated during the three seasons, mainly by nest censuses, territory mapping, nest monitoring and pellet/scats analysis. Other topics regarding predator-prey interactions, such as prey selection, will also be addressed in my PhD.
30 Tapio Gustafsson, Research secretary
I am working as a research secretary for Professor Ilkka Hanski. One part of my work is to take care of the computing hardware and software used in the MRG. I also produce illustrations for different purposes, including our website. I help to co-ordinate our group activities and write reports etc. During the last summer I was again teaching undergraduate students in the field course of Subarctic Ecology held at the Kilpisjärvi Biological Station.
At the beginning of this year I finished the big project, the MRG video. The video present the kind of research that has been conducted in our research group, but was mainly concentrated around the research on the Glanville fritillary butterfly Melitaea cinxia. I visited the Åland Islands in June and September 2000 and filmed undergraduate students, graduate students and post docs doing their field work. I also filmed the life and habitat of M. cinxia. I edited the film between November and January so that it was ready for the great presentation during the "Science Days" in January 2001. Finnish MTV3 used a clip of my film in their TV series "MTV Akatemia" in December 2000. Clips of the film was shown also in Italian TV between November 2000 and February 2001 because of Ilkka Hanskis Balzan Price last year. I noticed that making a long video is a BIG project. I had never filmed a video before, not to mention edit one. After 20 years of photography this was both very interesting and very challenging.
31 Sari Haikola, Post graduate student
On the basis of numerous studies it can be concluded that inbreeding lowers the general viability of an individual. It has been suggested that inbreeding depression should be low in species that have experienced inbreeding in the past. Nonetheless, there is also evidence suggesting that even highly inbred populations can suffer from inbreeding depression of high magnitude. I am addressing these questions in my PhD study. My main interests are in quantifying inbreeding depression in the Glanville fritillary butterfly, Melitaea cinxia, and investigating any possible relationship between the magnitude of inbreeding depression and a population`s past inbreeding history.
In our laboratory studies inbreeding had a negative effect on egg hatching rate and some other fitness components in Melitaea cinxia (Haikola et al., in press). Our results show that more continuous French populations suffered more severe inbreeding depression than small discrete populations from Åland, suggesting that deleterious alleles have to some extent been purged from inbred populations in Åland. Nevertheless, a substantial genetic load remains in the metapopulation. Given the occurrence of substantial inbreeding depression in Melitaea cinxia, one could expect that some mechanism for inbreeding avoidance has evolved. In the past year I conducted mating experiments to find out whether there is a difference in the mating success of inbred versus outbred males and whether butterflies avoid mating with their sibs (Haikola and Singer, in preparation). No evidence for lowered mating success of inbred males nor for avoidance of sib- mating was found.
Haikola, S., Fortelius, W., O`Hara, R.B., Kuussaari, M., Wahlberg, N., Saccheri, I.J, Singer M.C. and Hanski, I. Inbreeding depression and the maintenance of genetic load in Melitaea cinxia metapopulations. Conservation Genetics, in press.
32 Ilkka Hanski, Research Professor and Director of the MRG
I have worked in metapopulation biology for more than 10 years, but I continue to be excited both by the new research challenges and by the possible applications of the concept and more specific results in conservation and management. Much of the work is focused on our "model system" of classic metapopulation dynamics, the Glanville fritillary butterfly in the Åland Islands. My own research has been largely in metapopulation ecology, but I am keen to encourage and support genetic and evolutionary studies in the MRG, especially when strongly related to the ecology of the focal species.
Turnover rate in classic metapopulations is known to depend on ecological factors, such as population size and connectivity, but it may also be influenced by the phenotypic and genotypic composition of populations. The Glanville butterfly in Åland uses two host plant species, Plantago lanceolata and Veronica spicata, which vary in their relative abundances among distinct habitat patches (dry meadows) in the large network of ca 4,000 patches. We have found no effect of the use of particular host plant species on local extinction. In contrast, population establishment is strongly influenced by the match between the host species composition of an empty habitat patch and the relative host species use by larvae in the surrounding patches. We have now shown that this "colonization effect" is generated by host preference influencing the movement patterns of ovipositing females. Migrant females with dissimilar host preferences
1.0 have different perceptions of relative patch quality, which influences their likelihood of 0.8 colonizing patches with particular host composition. The figure illustrates the 0.6 consequences of the "colonization effect" by
0.4 showing the incidence function model- predicted metapopulation size of Plantago- Metapopulation size 0.2 preferring (open circles) and Veronica-
0.0 preferring (dots) butterlies in 19 habitat 0.0 0.2 0.4 0.6 0.8 1.0 patch networks against the pooled relative Veronica cover in the patch network Veronica cover in these networks.
Hanski, I. and Singer, M.C. 2001. Extinction-colonization dynamics and host plant choice in butterfly metapopulations. American Naturalist, in press (October 2001).
33 Paavo Hellstedt, Post graduate student
My Ph.D. research interests involved four aspects of stoat and weasel population biology: 1) Estimating the survival rate of captive-born least weasels in nature. We suggest that there are two main components explaining the differences of survival rate; the age of the animal, and time of year of release. 2) We also estimated the indirect effects of least weasel presence on Microtus-vole behaviour and demography. 3) In Lapland, we studied causes of change of the microtine cycles and the dynamics, habitat and prey selection of stoats. We suggested that change in mustelid densities refleced change in microtine populations. 4) We attempted to estimate the population size of stoats and least weasels and the relationships between individuals using molecular genetic methods.
Cycles of arvicoline in northern Fennoscandia have changed dramatically. Four - five year cycles have been replaced by annual fluctuations. Larger and clumsier, more predator-prone species have declined, and smaller agile species, better in escaping predation, have increased and become more stable. The earlier dominant predator, least weasel Mustela nivalis, is now much less common, and the stoat, M. erminea, prevails. In the absence of weasels, the pronounced cycles and population declines with the synchronous summer crashes among all prey species have disappeared. The summer-time predation by stoats has been suggested to prevent the increase of preferred prey items while the less preferred prey can support the overwintering of stoats. The consequent absence of high-density patches of preferred prey, an earlier characteristic for cyclic peak years, prevents the least weasels from increasing. In experiments with supplemental food, the densities of small vole species increase whereas the large ones do not, supporting the idea of selective predation by stoats. We monitored the habitat use of stoats with radio- tracking, and found dominance hierarchy in habitat use between and within sexes. Mature females live in the areas where the abundance of the preferred Microtus prey is the highest. Dominant as well as immature males live in less productive habitats than females, but in more productive areas than non-dominant mature males. The present abundant stoat population is obviously able to keep the preferred prey low.
34 Maaria Kankare, Post graduate student
My PhD project will consists of two parts. The first part is focused on the spatial genetic structure of the primary parasitoids (Cotesia melitaearum and Hyposoter horticola) and hyperparasitoids (Gelis agilis and Mesochorus sp. cf. Stigmaticus) associated with Melitaea cinxia on the Åland islands. According to ecological studies the primary parasitoids have very different spatial population structures. Hyposoter is present all over the Åland islands while Cotesia is spatially and temporally clustered in habitat patch networks. Hyposoter has stronger dispersal ability and occurs in more isolated and smaller host larval groups than Cotesia. As a consequence of these behavioral differences, H. horticola and C. melitaearum are expected to show dissimilar spatial patterns. The aim of the study is to compare the genetic structure and population structure of these parasitoids. Results can then be compared to the host butterfly Melitaea cinxia population structure. I am developing microsatellite markers to study these questions.
The second part in my PhD project is to construct a molecular phylogeny of Cotesia (Hymenoptera: Braconidae) species associated with melitaeine butterflies from different host species in different geographical areas. Members of the genus Cotesia are important parasitoids of butterflies belonging to the tribe melitaeini, which form a distinct group in the family Nymphalidae. Some of the Cotesia species are generalists and use several different host species, whereas other Cotesia species appear to specialize in a single host species throughout their range. I want to compare the Cotesia phylogeny to the host butterfly phylogeny. I am interested in whether Cotesia species have coevolved with their host butterflies or they have colonized an already diverse group of hosts. I also want to study the intraspecific variation in different Cotesia species to see whether the differences are substantial enough to suggest the presence of cryptic species. I am using mtDNA sequencing to construct the molecular phylogeny of Cotesia. I have sequenced part of the two mtDNA genes COI and NDI and have a total of about 2200 bp. According to the preliminary results there are genetic differences between geographic regions. But there are also differences among parasitoid populations using different host species in the same region. This could suggest the presence of cryptic species.
35 Laura Kivistö, Post graduate student
Ever since I attended the basic lichen course in 1993, I have been interested in the magical world of lichens. Lichens are actually kind of mini-ecosystems consisting of at least two organisms: a fungus and a photosynthetic partner. My research focuses on the effect of old-growth forest fragmentation on epiphytic lichens. Actions to maximize tree productivity in managed forests, e.g. short rotation cycles, tree monocultures and even-aged tree stands, are the most important factors at stand level that affect epiphyte communities. Forest owners need effective tools to estimate the effects of forest management on biodiversity. Indicator species have been widely used to this purpose. Using old-growth forest lichen species I have examined 1) if isolation from a large old-growth forests affects the epiphytic lichens, 2) how different lichen species respond to old-growth forest fragmentation, i.e. are old-growth forest specialists more sensitive than common generalist species, and 3) what structural elements in the forest fragments are necessary for the survival of old-growth specialist lichens. The age of the dominant trees of the forest stand appears to be the most important factor affecting old-growth specialist lichens. The importance of stand age can not be emphasized too much; rotations should be prolonged in managed forests and more old-growth forests should be left unlogged to maintain the diversity of old-growth specialists. At stand level, some old and large tree individuals should be left in managed forests as “a legacy” for the next generations of several organisms. Especially old aspens and willows host a very rich community of epiphytes.
Lobaria pulmonaria is one of the old-growth forest indicator species in Finland. It grows usually on old Populus tremula and Salix caprea trees. Photo Kimmo Jääskeläinen.
36 Pierre-Alexandre Landry, Post doc
1) The genetic differentiation of spatially structured population system. Can the evolution of a group of populations be predicted? My research is focusing on the association between environment, demography and the genetic diversity of natural populations. I am mainly trying to understand the effects of barriers to dispersal on the genetic diversity and differentiation of isolated populations. During my PhD work, I have studied an insular system on a lake in Quebec, inquiring the population genetics of populations of a small rodent (namely the deer mouse, Peromyscus maniculatus). I joined the MRG in January 2001 to continue a similar research program with another small mammal species, the common shrew (Sorex araneus). My objective is to integrate ecology-based models (such as Incidence Functions) and population genetics data (microsatellite DNA) to determine whether demographic and environmental variables can be employed to predict the genetic diversity of populations occupying a network of habitat patches. In addition to genetic data obtained from a set of natural populations, these questions are also addressed by using computer models, simulating the distribution of alleles in relation with the spatial structure of populations, the balance of extinction/recolonisation events, the dispersal capacity of individuals, and allele mutation processes.
2) Phylogenetics and microsatellite data. Microsatellite markers are increasingly used to derive the evolutionary relationships among populations, provided that the genetic information is transformed into a distance matrix prior to tree reconstruction. To do so, various indices were developed to infer the time since divergence between populations from actual allelic composition, integrating information from allele frequencies or differences in allele sizes. However, some do perform better than others, depending on a series of factor (including mutation rates of loci, populations historical relationships, genetic drift, gene flow,…). Results of tree-reconstruction methods, as well as validation procedures (such as bootstrap and jackknife) can be greatly affected by the choice of a coefficient. Regarding these problems, my intent is to provide empirical guidelines to select the index that better suits a given data type.
37 Anna-Liisa Laine, Post graduate student
I am a second year post graduate student in the MRG, with a background in plant ecology. For my MSc thesis I developed a patch model for an endangered plant species with an emphasis on practical conservation application. I am still interested in population level dynamics of species in a defined spatial context, now at the community level of closely interacting species. What regulates these dynamics and how the feedback mechanisms work in often ambiguous co- occurrences is what I believe to be a key component of ecology and biodiversity.
One of the most common interactions we encounter in nature is that between hosts and their parasites. All natural populations of plants support a high diversity of plant pathogens ranging from viruses to fungal diseases. However, how these pathogens affect their hosts at the spatial, population, and genome levels, and vice versa, is still poorly understood. I approach these questions in system where Plantago lanceolata is a host to its powdery mildew, Sphaerotheca plantaginis (Erysiphales). Field surveys are conducted in the Åland islands where P. lanceolata meadows are abundant but highly fragmented. This fragmented structure is also reflected on the distribution of the fungus, which is relatively rare despite the abundance of the host. The fungus distribution may be limited by its dispersal abilities, unsuitable microenvironment or host resistance to the fungus. The dispersal of S. plantaginis is studied both at the within host population level and at the regional level using occurrence data obtained from annual surveys of the Melitaea cinxia study system. Results indicate dispersal within a host population to be diffusive over short distances. However, the short life-cycle of the fungus and occasional secondary foci produced further away from the original disease focus result in a large proportion of the host population being infected by the end of the growing season. The results of the regional surveys conducted in September 2000 indicate the fungus distribution patterns to be highly nested. The extent to which fungus distribution is limited by host resistance is currently studied in a greenhouse experiment in a cross-inoculation design of two pathogen strains. Host susceptibility is studied in a spatially linear context where the marginal populations are infected by the powdery mildew and the central populations are disease free. With this study I hope to gain an understanding of the extent to which host resistance determines fungus occurrences and of the underlying genetic processes of the virulence-resistance dynamics of this system.
38 Atte Moilanen, Researcher
In the MRG I do mostly computational work and software development. My interests include spatial population dynamics, and the construction, parameterization and application of predictive metapopulation models. I am specialized in numerical optimization and programming, and I have an interest in modeling.
For the past year I have been heavily involved in the development of a computational tool for the analysis of metapopulation dynamics. This tool, called SPOMSIM (Stochastic Patch Occupancy Model SIMulator), can be used for estimating parameters for SPOMs, and for producing predictions about metapopulation dynamics. SPOMSIM also includes (among other things) a metapopulation site-selection algorithm (Moilanen and Cabeza 2002), and a patch system editor, which makes it easy to investigate the consequences of changes in landscape structure. Potential uses of SPOMSIM include scientific studies, teaching, and conservation analysis. For example, consequences of habitat loss or the feasibility of a species reintroduction may be analyzed using SPOMSIM. Another major ongoing project for me is work with reserve design and metapopulation dynamics in collaboration with Mar Cabeza, please see her page for more information. For me a highlight of this year was a study I did with Marko Nieminen about “Simple connectivity measures in spatial ecology” (Ecology, in press). We examined the performances of three commonly used connectivity measures (Nearest Neighbor, BUFfer and Incidence Function Model measure) using both meta-analysis and empirical data. We found that the NN measure, which has been used by about half of recent publications concerning connectivity, has exceedingly poor performance. The figure below shows the performance of the measures with a large empirical data set when part of the data is assumed to be missing. The coefficient/standard error -ratios for the IFM and buffer measure are much higher than that for the NN measure. Importantly, there is a large range of data set sizes for which the NN measure fails to find a significant effect of connectivity while the IFM and buffer measures still do fine.
39 Marko Nieminen, Researcher
My current research focuses mainly on studies of the Glanville fritillary butterfly Melitaea cinxia in the Åland Islands, SW Finland. Two main lines of research are: (1) To study the significance and variability of different causes for the spatially correlated dynamics in M cinxia metapopulations, and the spatial scales at which they operate. Two factors are probably driving these spatially correlated dynamics; weather and changing landscape structure. They also operate indirectly via several factors (host plant characteristics, parasitoids, inbreeding effects and habitat quality) which in turn may have direct effects. (2) Running the bi-annual monitoring of all known suitable habitat patches. We collect data on habitat characteristics and larval nests every autumn, and on the numbers of larvae and parasitoids in the spring.
The latest results from the monitorings show that there was a population crash almost everywhere in Åland during summer 1999, due to a severe drought. Very low winter mortality occurred in the winter 1999-2000, which was followed by a favourable summer during 2000. These episodes resulted in many colonizations of empty habitat patches and/or large increases in population sizes in most areas in 2000 (see Figure). These latest results allow a more comprehensive analysis of colonizations than has been possible with previous census data.
Changes in the numbers of occupied habitat patches and larval groups within subareas of Åland from 1999 to 2000. (Left-hand arrows show the direction of change in no. of occupied patches and right-hand arrows in no. of larval groups).
40 Saskya van Nouhuys, Post doc
I study the population ecology and the evolution of interacting species. Most of the work that I have done is focused on the interaction between parasitoids, their hosts, and host food plants. For my Ph.D. (finished in 1997) I studied natural selection on parasitoid searching behaviour, and genetic differentiation of behaviour among parasitoid populations from wild and cultivated host food plant habitats. As a post doc with Ilkka Hanski (since 1997) I work primarily on the large and small-scale population ecology of the parasitoids associated with the Glanville fritillary butterfly in Åland, Finland. I am interested in the ecological and evolutionary consequences of parasitoid dispersal, competition, hyperparasitism, behaviour and life history variation.
This year I worked mostly on four projects 1) Parasitoid population dynamics: I have continued to monitor the long-term population dynamics of the parasitoid Cotesia melitaearum which persists in Åland in small tightly clustered populations. 2) Competition among parasitoids: A student and I found that the outcome of direct competition between the two parasitoids of the Glanville fritillary depends on when in the life cycle of the first parasitoid the second parasitoid enters the host. 3) The effects of plant defensive chemistry on parasitoids of herbivorous insects: I began a collaboration with researchers at the Netherlands Institute of Terrestrial Ecology to measure the impact of the defensive chemistry of the plant Plantago lanceolata on parasitoids. 4) Parasitoid behavior: A student and I continued to study the natural history of an extremely mobile parasitoid which manages to parasitize 1/3 of the larvae of Glanville fritillary butterfly in Åland even though the hosts are susceptible to parasitism for less than a day of their entire life cycle.
41 Toshka Nyman, Laboratory technician
I have been working in MRG since the beginning of 2001, as a laboratory technician. My tasks are to run the day to day laboratory work for the Molecular Ecology Team. Mostly this means mtDNA extraction and setting up PCR and sequencing reactions. In order to be more useful I have learned to run the ABI 377 DNA sequencer, so that any occasional absence of the technician who runs the machine does not interfere with the team's work. I am also responsible for the supplying of materials, chemicals,enzymes etc., needed for the current laboratory work.
42 Bob O´Hara, TMR Post doc
I am working in the group as a statistician, analysing data, helping other people to analyse their data and trying to make comments on other people's analyses that sound wise. The main thrust of my work is developing Bayesian methods for the analysis of ecological data. The Bayesian approach gives the statistician a large amount of flexibility in modelling the data. I have been developing methods for fitting the Incidence Function model to metapopulation data, and am now focussing on adding environmental stochasticity into the model, potentially using specific environmental variables (e.g. rainfall) as covariates in the estimation. This work has been carried out in collaboration with Elja Arjas and Hannu Toivanen from the Rolf Nevanlinna Institute.
As I write, I am being employed by the Finnish Meteorological Institute (FMI) to analyse data obtained by Reijo Penttilä (not of the FMI) on dispersal of his favourite wood rotting fungus (Phlebia centrifuga). I am looking at the dispersal of the spores, with the intention of comparing this to models of the movement of the spores which are being developed by the meteorologists. I am also analysing spore production data, correlating the rate of production with meteorological variables. I also have an on-going collaboration with Johan Kotze analysing distribution maps of beetles. We have already shown that the observed positive correlation between abundance and range size of carabid species in Holland, Belgium and Denmark can be explained as being due to differences in the degree of specialisation of the beetles - as predicted by the 'resource breadth hypothesis'. We have also looked at the changes in the beetle populations, and have found, amongst other things, that species which are dimorphic for wing form (i.e. individuals of the same species having either long or short wing) are not declining as rapidly as either the long or short winged species. We are now working on designing experiments to trap beetles migrating between islands (see photo).
43 Otso Ovaskainen, Post doc
I completed my PhD on mathematics in the Technical University of Helsinki in1998. As I have interest in ecology, I was happy to join the MRG in June 1999. Since that my main research interest in the MRG has been in the mathematical analysis of spatially structured metapopulation models. I have studied mainly spatially realistic models, meaning that I take into account the areas and spatial locations of the habitat patches, but ignore any further details. This choice has turned out to be a fruitful compromise: the models are simple enough for analytical tractability, but realistic enough to give a quantitative description of metapopulation dynamics in heterogeneous landscapes.
In the year 2001 I extended my earlier studies of deterministic metapopulation models by analyzing the concept of ‘patch value’, attempting to answer the question “how much does an individual habitat fragment contribute to metapopulation dynamics?” The main lesson from this exercise was that the value of a particular patch depends on the question asked. For example, an isolated patch may contribute little to the average size of a metapopulation, but may still be important for the long-term persistence, especially if local extinctions occur in a spatially correlated manner.
In addition to considering patch values, I attempted to analyze stochastic patch occupancy models (SPOMs). Consider a network of n habitat patches. As each patch may be either empty or occupied, there are 2n different states in which the system may be. Consequently, large systems can never be solved analytically, and had so far been analyzed only through simulation studies. I attempted to develope a computationally feasible approximation method, which may be used to analyze the behaviour of a SPOM by transforming the original heterogeneous metapopulation into an 'ideal' metapopulation inhabiting a network of identical and equally connected habitat patches. The transformation to the ideal metapopulation is based on weighting the individual patch occupancies by the dynamic values of the habitat patches. The method may be applied to SPOMs with flexible structural assumptions and with temporally varying and spatially correlated parameter values.
44 Jodie Painter, Researcher
2001 has been my third year as a Post-Doc in the MRG. My research involves applying molecular genetics to address questions of population ecology. I am particularly interested in mating systems, and also phylogenetics. In addition to doing my own research, as a senior researcher in the Molecular Ecology team I advise and teach other MRG members wishing to add a molecular component to their ecological studies. As our laboratory is a facility shared by other groups in the Department, I also coordinate with other group leaders in our efforts to facilitate the day to day running of the lab. In 2001, we have spent some time planning the layout of our new laboratory, housed in the Biocenter at Viikki.
I have worked on two primary research projects during the past year. One is investigating the mating system of the Siberian flying squirrel, by determining paternity of young in three locally studied populations. I have now developed 7 polymorphic DNA microsatellite markers for this species, and assisted by Vesa Selonen have been using these to generate data for paternity analyses. Currently, 39 family groups observed during the past four years have been genotyped, the samples including the breeding female, her young and all males whose home range overlapped that of the female. At present we are combining this information with movement data from radiotracking studies to compare realised paternity with male home range size and quality. This project will be concluded by genotyping additional individuals sampled during the summer of 2001. The second project is primarily the investigation of possible post-glacial dispersal routes of an endangered boreal forest specialist beetle, Pytho kolwensis. This study has been expanded during the past year to include samples from two other Pytho species: Pytho abieticola, another rare boreal forest dweller, and Pytho depressus, a common beetle that also occurs throughout southern Europe. For all species, we have mtDNA (CO I) haplotype information for samples collected from localities in Sweden, Finland, western Russia (close to the Finnish border), Lake Baikal, and north-eastern China. One interesting result from this study is a very low level of genetic variation among individuals of P. kolwensis and P. abieticola, the boreal forest specialists. Another is the presence of western boreal haplotype families in China, while ‘eastern’ haplotypes are strictly restricted to Chinese sampling localities. This project will be concluded by adding samples of P. abieticola and P. depressus collected during two expeditions to the Ural mountains over the summer. For more details on this project see the MRG Scientific highlights section (p. xx).
45 Reijo Penttilä, Post graduate student
I am interested in the population and community ecology of wood-rotting fungi, and of polypores in particular. My studies are part of the project ”Biodiversity in Boreal Forests”, led by Ilkka Hanski. Hence, I work at two different locations. In the summer and in the autumn I organize and conduct field work at the Research Station of the Friendship Park in Kuhmo, and in the winter I work as a post graduate student at the University of Helsinki. My PhD project deals with the effects of forestry and forest fires on wood-rotting fungi, and my studies focus on both the community structure and on the population structure and population dynamics of old-growth forest fungal species. I have also examined the dispersal ability and genetic structure of fungal populations.
In a recent study, I sampled the abundance and distribution of polypore species in a very large, continuous area of old-growth forest in Russian Karelia, and in a set of rather small, fragmented old-growth forest patches in mid-eastern Finland. The results demonstrate that the number of threatened polypore species, and the number of old-growth forest indicator species, are higher in the continuous forest area in Russia than in the forest fragments in Finland. Moreover, intraspecific abundances within species were very much higher in Russia than in Finland. These differences are most likely due to the fragmentation and isolation of old-growth forests in eastern Finland by intensive forestry. In another, collaborative study, we examined the effects of the fragmentation and isolation on old-growth forest species in a large fragmentation project in Kuhmo and Pohjois-Häme. Our preliminary results suggest that certain old-growth forest fungi (e.g. Amylocystis lapponica, Phlebia centrifuga) suffer from the isolation and fragmentation of suitable habitats. My extensive studies on the dispersal and spore production of an old- growth forest specialist fungus, Phlebia centrifuga, have shown that the dispersal of this species is strongly concentrated to the close vicinity of the fruitbodies. I have also made extensive measurements of several weather and landscape variables. I am now combining this information with data on dispersal and spore production in P. centrifuga, to develop a dispersal model aimed at predicting the dispersal of P. centrifuga under different environmental conditions. This is a joint study which involves several researchers and research institutes.
46 Juha Pöyry, Post graduate student
I started my PhD project in the beginning of 2000. My main objective is to empirically examine the effects of cattle grazing on insect populations. Based on this information, I will create recommendations for practical habitat management. I will also compare various local and regional factors affecting the total species richness of insects, and the occurrence of individual species, in semi-natural grassland habitats. These factors include for instance the species richness of plants, the intensity of grazing and the regional density of semi-natural fragments of grassland. My target taxa are mainly Lepidoptera (butterflies and moths) and Apoidea (wild bees). Even though my thesis is supervised by prof. Ilkka Hanski, I am permanently based at the Finnish Environment Institute (FEI) in Helsinki. Here, my work is a part of the larger project "Maintaining biodiversity in traditional rural landscapes. Optimal management and area networks", headed by Dr. Mikko Kuussaari and funded by the Finnish Biodiversity Research Programme (FIBRE).
In the year 2001, I collected two large data sets in the field, which both continue with the study setting started in 2000. The aim is to find out whether the insect diversity of a grassland fragment is better explained by the characteristics of the fragment itself, or by the amount of grassland habitats in the surrounding region. These hypotheses will be tested in a subset of 48 grassland sites from the national survey of traditional rural habitats. The first target group studied is Apoidea (and other Aculeate wasps). They were sampled four times during the season. Two sampling methods were used: quantitative transect-netting with a 0.25 ha sampling area in each meadow and qualitative search with netting-time related to the size of a meadow. Besides, pollinator-traps were used in 10 sites to compare the pollinator populations to the catches in the previous year. The second target group consisted of micro-moths feeding as larvae on the Burnet Saxifrage (Pimpinella saxifraga). The larval stages were searched and sampled three times during the season to study occurrence and abundance of the species specialised feeding on this plant in Finland. The rearing of larvae also produced data on the natural enemies (mainly parasitoids) of these moths.
47 Tomas Roslin, Post doc
My main interest is in the empirical analysis of spatial population structures: where in the landscape a species occurs, how tightly linked the local populations are by dispersal, and what implications this may have for the population dynamics and evolution of the species. In my current project, I am using leaf-mining and galling insects on English oak (Quercus robur) as a model system. From these host-specific insects’ point of view, individual oak crowns represent islands of suitable habitat in a sea of unsuitable habitat. As oak occurs both as isolated trees and in stands of varying density, I can analyze how variation in the configuration of the host-tree archipelago affects central population processes among the insects.
In the summer and autumn of 2001, my field work is focused on three particular questions: how dissimilar do different oak tree islands appear to insects, how readily do insects disperse between islands, and do local insect populations adapt to the particular characteristics of their host tree? Chemical differences between trees are being analyzed in collaboration with the Environmental Chemistry Program at the University of Turku. Insect dispersal is being monitored with the aid of potted oak trees placed at given distances from an oak stand. Finally, local adaptations are being studied by experimental transplants of the moth Tischeria ekebladella to a set of dissimilar oak phenotypes. Here, a significant part of the work is done by masters student Sofia Gripenberg. With the field work completed in November 2001, I will leave for a year- long post doc with Prof. Jens Roland at the University of Alberta. As a natural extension to my current project, my work in Canada will focus on the interaction between landscape structure, defoliation by the forest tent caterpillar Malacosoma disstria, and its impact on local communities of galling and mining insects sharing the same host tree, the trembling aspen (Populus tremuloides).
48 Tarja Salmi, Post graduate student
In January 2000, I moved into the MRG from the Department of Forest Ecology, where my main subject was silviculture. My Master's thesis (completed in 1999) dealt with the external quality of the trembling aspen (Populus tremula), and within the MRG, I will continue to work on this same tree species. In my PhD project, I will examine the population biology of aspen in both old-growth and managed forests. I will work at three different levels. At the level of the individual tree and the stand, I will study the reproductive biology of aspen (including sex ratio, seed dispersal and regeneration) in old-growth forests without large-scale disturbances. At the landscape level, I will assess the extent of and the reasons for the spatial aggregation of mature aspen trees in both managed and virgin forests.
My work will be based on an already compiled data set with spatially referenced data on ca 30,000 mature aspen trees. This data shows that there is 5,5 m3/ha aspen wood in old-growth forest whereas in managed forest there is only 0,8 m3/ha. The altered structure of managed forest can be seen also in other ways. In old-growth forest more than 70 % of the aspen wood is alive and 25 % is dead. In managed forest these figures are the other way round. In fact, in this large area of managed forest (4000 ha) one third of the dead aspen wood was either girdled or notched ie. artificially killed. In year 2000 and 2001, I collected additional data on the regeneration of aspen. Thus, I now have data on all trees (>1 cm at breast height) within 50 hectares of old-growth forest and 30 hectares of managed forests. I will then start analysing data on the spatial aggregation and dynamics of coarse woody debris as well as on the regeneration of aspen. I have also cored trees to study the age distribution and history of the stand development. In summer 2001 we did (in cooperation with Leena Suvanto, see p. xx) field experiments on the germination of aspen seeds under different conditions. Aim was to see do aspen seeds germinate in the nature and what is the limiting factor for sexual reproduction. We are also interested to find out what kinds of conditions are needed, if germination occurs and in which phase does mortality occur? Germination occurred in the experiment. Preliminary results show that seedlings emerged most successfully in the plots with watering and seed cover.
49 Alia Sarhan, Post graduate student
I joined the MRG early this year, with a background in molecular genetics. Here, my studies are focused on the population genetics of the Glanville fritillary Melitaea cinxia. Genetics is likely to play an important role in driving the butterfly’s metapopulation dynamics, especially in inbred populations. With molecular tools one can estimate gene flow between the different populations. In addition, the degree of inbreeding within each population can be assessed by estimating the effective population size. This can then be correlated with fitness and extinction risk. For the Melitaea cinxia system, genetic data can be complemented with the very extensive ecological and population history data for this species.
At the moment, an important part of my research consists of developing microsatellite markers for Melitaea cinxia. To date, I have sequenced over 300 clones of a library enriched for microsatellites. Unfortunately, in this taxon, the level of polymorphism is extremely low, even for very long repeats. Out of the first 200, I have succeeded in developing one variable marker, as well as three others with only few alleles. I will soon begin to look at the distribution of alleles in the different populations, when more markers will be available.
50 Mika Siljander, Research assistant
Our annual field surveys of Melitaea cinxia produce a vast amount of data. My main task within the MRG is to manage all these data in an accessible form. The current database was built in Microsoft Access 97, and it has been linked to the ArcView GIS system. Hence, it is now easy to produce all kinds of visual output from the database (for an example, see picture below). Overall, the metapopulation database is in a state of rapid expansion - not only due to the addition of new data from the biannual field surveys, but also due to the aggregation of other types of spatially referenced data. Over the last few years, we have mapped the M. cinxia patches with GPS technique, we have obtained data on patterns of rainfall from a weather radar station and we also have obtained fine-scale data on fluctuations in temperature from different parts of Åland. As the metapopulation database continues to grow, my biggest challenge remains to manage all different spatial data in a single, functional format.
Relative changes in the population sizes of Melitaea cinxia between 1999 and 2000. Downward triangles indicate a decrease and upward triangles an increase in population sizes.
51 Janne Sundell, Post graduate student
My research interest focuses on the population dynamics of microtine rodents. In my PhD project, I experimentally tested the hypothesis that the cyclic vole populations in the northern Fennoscandia are driving by small mustelid predators. In a large- scale field experiment, I perturbed natural vole-weasel dynamics by adding weasels to prevent increase of vole populations. Subsequently the aim was to keep the vole density at a permanently low level by further additions of weasels. The experiment was started in 1997 and discontinued in 2000. According to preliminary results, the experimental additions of predators failed to change vole dynamics in any of experimental areas. The weasels used in this experiment came from captive breeding program. This part of the project produced valuable information on various aspects of the reproduction biology and demography of the least weasel.
My other interests include the functional response, predation rate and the prey choice of the least weasel. Overall, I would like to know more about how species identity, functional group and size affects vulnerability of a vole to weasel predation. I have studied these issues in the large outdoor enclosures and in the laboratory as well as observations coming from field. These studies have also elucidated hunting behaviour and activity patterns of the least weasel. I have been also interested in the effects of predation and predation risk on stress level, behaviour, reproduction and survival of voles. Other side path of my studies concentrate on the impacts of avian predators on vole dynamics at a large spatial scale. All of my work serve one common goal: to understand more about the effects of predation on small mammal dynamics in Northern Fennoscandia. I aim to defend my PhD thesis in 2001.
52 Leena Suvanto, Post doc
I’m working on the project called "Population biology of trembling aspen, Populus tremula". This project deals with dynamics, reproductive biology and regeneration of aspen both in old growth and managed forests. I am responsible for the genetical part of the project. My main tasks are to find molecular markers for clone identification, to look at the genetic variation of aspen in Finland and to find out why sexual reproduction is so rare in aspen.
During the last year I have been testing microsatellites for clone identification. At the moment I have nine loci, which were originally developed for P. tremuloides, a close relative of P. tremula. These microsatellites amplify well and are polymorphic also for P. tremula. I have collected leaf samples of 199 trees (65 clones) from old-growth and 127 trees (40 clones) from managed forest from Kuhmo, north-eastern Finland The putative clones were identified according to morphological markers namely the size and colour of young leaves, branching type and trunk shape. Preliminary results show that microsatellites are able to differ even morphologically similar clones i.e. they are a better method for clone identification than morphological markers. I’m planning to use these same microsatellites to study the genetic diversity of aspen in Finland. Sexual reproduction is rare in P. tremula; it reproduces mainly through suckering. Despite of this, viable seeds are produced every year. The seedlings need enough light, water and exposed warm mineral soil to survive. These conditions are prevailing after forest fires, which are rare at present. This summer we have had a sowing experiment in Kuhmo. There we have sown seeds of aspen to a clear cutting and a burnt area. We have looked at the effect of watering, sowing cover and exposed mineral soil. Preliminary results show that water is very essential for the germination of aspen seeds. We have also noticed that new seedlings can emerge as long as one month after sowing. Earlier it was thought that seeds are viable only for a couple of weeks after they are shed.
53 Gergely Várkonyi, Post graduate student
My main research interests are the ecology and taxonomy of insects, especially of parasitoid wasps and their hosts. My PhD project concerns the biology of periodical Xestia moths and their parasitoids in northern Finland. My thesis will contain studies on the following: the host-parasitoid interaction that maintains the alternate-year occurrence of Xestia moths, the estimation of population parameters important to this interaction, the early larval parasitoid assemblage attacking Xestia species, spatial patterns of the host and the parasitoid, dispersal ability of Xestia adults in ecological corridors, and population genetics of Xestia tecta. Since October 1998, I have also been involved in the "Biodiversity in boreal forests" project. I have been co-ordinating one of the main sub-projects, entitled "Impact of forest fragmentation on population survival", as well as the insect studies conducted in Kuhmo field site in eastern Finland.
Many insect species with fixed k-year life cycles emerge synchronously in large numbers every kth year. In the intervening years, few (or no) individuals hatch. Populations of these so-called periodic insects can be divided into as many as k temporally isolated cohorts. The important population dynamic question is what maintains the abundance difference between the sympatric cohorts. We have studied boreal Xestia species (Noctuidae) with striking two-year periodicity. We have found unique evidence which supports the hypothesis that the rare Xestia cohort in eastern Finnish Lapland is regulated by a parasitoid wasp, Ophion luteus, with one-year life cycle. The wasp generations parasitizing the abundant host cohort attack the rare cohort, and prevent it from growing in size. Larvae and
10000 pupae of Xestia moths have such an important 1000 role in the local food 100 web, that even the 10 population size of the generalist predator 1 shrews (genus Sorex) is 0.1 Xestia Ophion Sorex fluctuating with the 0.01 Xestia numbers (see 77 82 87 92 97 time series).
54 Anu Väisänen, Research Secretary
My background is in freshwater ecology, but at the moment I work as a research secretary mostly dealing with the administrational issues. The main tasks are to help with co- ordination of the projects, manage the budget and the payment transactions and to help to prepare proposals and reports. Daily co-ordination includes updating the web-pages and correspondence with the researches.
This year we have had many foreign visitors and I have used lots of my time arranging these visits. In August we hosted a Chinese delegate of five members, a return visit from Heilongjiang Research Institute. I prepared them a 2-week schedule and guided this tour as well. The program included visits to several field stations as well as a visit to Ahvenanmaa.
Old-growth forest in Kuhmo.
55 Laboratory facilities
Helsinki
The MRG is located in the 3rd floor in the Division of Population Biology, Department of Ecology and Systematics, in the street address Arkadiankatu 7. We have 8 offices, which are currently shared by 20 people. We share a molecular laboratory with other members of the Department. The molecular laboratory is fully equipped for PCR (polymerase chain reaction)-based projects, such as mtDNA sequencing and screening DNA microsatellites. Equipment includes PCR machines and centrifuges, allozyme, agarose and acrylamide gel electrophoresis equipment and facilities, and an ABI 377 DNA sequencer (with a full-time technician who runs the machine). We also have facilities for both DNA cloning and the use of radioisotopes. And finally, we are building an extensive GIS- laboratory (GIS based data management system) for managing the Melitaea cinxia- database and all other map-related information important for the research group.
The table below shows the amount of space occupied by the MRG.
Space no. m² Offices 8 150 DNA-laboratory* 1 120 GIS-laboratory 1 10 Total 10 280
* = shared with the rest of the Department of Ecology and Systematics.
56 Tvärminne
The primary aim of the project at the Tvärminne Zoological Station is to maintain capacity for experimental studies of the Glanville fritillary Melitaea cinxia project. Current research is focused on quantifying inbreeding depression in Melitaea cinxia and on clarifying the possible relationship between the magnitude of inbreeding depression and populations´ past inbreeding history. The results so far indicate a significant reduction in fitness due to inbreeding, the effect being more severe in continuous than in naturally fragmented populations. The project was started in Tvärminne in 1996. During these years the laboratory conditions and the rearing routines have been developed to an appropriate level to facilitate our experimental research. Adult butterflies are mated in a flying room with a large number of quartz glass fluorescent lamps, using six different broad spectral luminescent substances and oscillation frequency of 30 000 Hz. The resulting light is very close to natural light, including the proportion of UV radiation, and it practically does not oscillate. The plants needed for larval food and female egg laying are grown in a 3.65 by 7.10 m greenhouse, built specifically for this purpose. The greenhouse enables the rearing of larvae all year round and so gives the possibility of rearing more than one generation of butterflies per year.
Lammi Biological Station
The Lammi biological station has a large greenhouse (34 by 17 m), which we used for a pilot experiment on the movement behaviour of the Glanville fritillary. We reared butterflies from two different origins with different host plant choice (Saaremaa and Åland), and released marked butterflies in the greenhouse to study movements, matings and reproduction. Unfortunately, the experiment largely failed. Weather conditions were exceptionally adverse in June, and only a few days were favourable for butterfly flight. The structure of the greenhouse should also be changed to make it more appropriate for the kinds of experiments planned.
Field sites
Åland Islands
In the Åland Islands in SW Finland, the research is focused on the Glanville fritillary (Melitaea cinxia), its parasitoid wasps and larval host plants. The main Åland island contains thousands of habitat patches (dry meadows) where at least one of the two larval host plant species, Plantago lanceolata and Veronica spicata,
57 occurs, and which are considered to be potentially suitable for the Glanville fritillary. In each autumn, all known habitat patches are surveyed for the presence of larval groups of the Glanville fritillary, as well as scored for several habitat patch attributes. The latter include information on the occurrence of the host plants, landscape structure and habitat quality. In the following spring, all patches occupied in the previous autumn are re-visited, and the numbers of larval groups, numbers of larvae and numbers of cocoons of the local specialist parasitoid wasp Cotesia melitaearum are counted. This large-scale monitoring work has accumulated a comprehensive and unique database on the occurrence of the Glanville fritillary and on the habitat patch characteristics. Moreover, all the habitat patches are currently being positioned with an accurate GPS-machine, which allows analyses of the spatial patterns and properties of the patch network with GIS. Based on this monitoring work, we know the locations of the vast majority of the suitable habitat patches in Åland, totalling about 4200 patches on the main islands in 1999. The habitat patches are distributed across the Åland’s land area of 1480 km2 , but most of them occur in clusters, typically of tens of patches. The main reason for the aggregated distribution of habitat patches is that the meadows mainly occur within the cultural landscape on rocky outcrops, typically near small villages. The patch-aggregates form well over one hundred habitat patch networks, many of which are occupied by the Glanville fritillary, and where the respective metapopulations have relatively independent dynamics. In 1999, about 360 patches were occupied by the Glanville fritillary. The average size of the habitat patches is only 1200 m2, and the mean and median population sizes are only 4 and 2 larval groups, respectively (which translates into about 80 and 40 full-grown larvae on average). Therefore, it is easy to understand that there are numerous turnover events (extinctions and colonizations) in each year. For example, from 1998 to 1999 we recorded 40 colonizations and 126 extinctions. The turnover events are to a large extent correlated spatially, but different parts of Åland typically have independent contradictory trends between any two years.
Kuhmo
In the past 100 years, modern forestry has dramatically changed the Finnish landscape. Today the amount of old-growth forest remaining increases from the most densely populated south to the north, as well as from the western coast to the Russian border. On the other hand, because of climatic reasons, the natural species diversity of forest-specializing organisms decreases to the north. From these facts one may conclude that the most favourable area for studying forest-dwelling
58 species is Kuhmo in eastern middle Finland. A further important feature is that there is a large extent of virgin forests nearby in Russia, which maintains viable populations of taiga species and may serve as a source for isolated Finnish populations.
Fallen trunks in the old-growth forest in Kuhmo. Photo Reijo Penttilä.
These reasons led to cooperation between Ilkka Hanski’s MRG (Helsinki) and the Research Centre of the Friendship Park (Kuhmo), in the framework of a major mutual project entitled ”Biodiversity of Boreal Forests”. Research in Kuhmo has concentrated on spatial and temporal responses of old-growth forest species to forest management on the role of two deciduous tree species in old-growth forests and on the biology of endangered taiga species. By studying species diversity in small fragments of old-growth forest we attempt to assess the extinction debt in small forest fragments. Empirical data on a wide range of taxa, sampled from 23 forest fragments will be related to the history of forest fragmentation around each study fragment. Fragmentation may also cause extinction cascades, when the base of a specialized food chain disappears, as we have shown in the case study on a polypore fungus – moth – parasitoid chain. Aspen and goat willow, both living and dead, represent essential microhabitats for a diverse group of organisms in boreal forests. We have mapped all aspen and willow trees larger than 10 cm DBH within an area of 120 km2. Studies on spatial population structure and dynamics of organisms associated with
59 the aspen, like the lichen Lobaria pulmonaria, several mosses and beetles, have been conducted by using the database on the host tree distribution. The beetle Pytho kolwensis, living in virgin spruce forests, has been one of the target species while studying the biology of endangered old-growth forest species. Special emphasis has also been put on research on spore dispersal of the endangered saproxylic fungus Phlebia centrifuga. Long-distance spore dispersal is very rare, which probably prevents patch to patch colonization in fragmented landscapes. We have started a population genetic study selected old-growth forest species including the beetle P. kolwensis. We have compared the behaviour of two moth species in a mosaic of small fragments of old-growth in otherwise managed forest landscapes. In a mark- release-recapture study we tested the significance of ’ecological corridors’ and ’stepping stones’ for the moths. Both Xestia speciosa and X. rhaetica, a generalist and an old-growth forest specialist species, respectively, preferred corridors for dispersal, but were also able to cross wide sapling stands. However, they both avoided clearcuts.
Weasel-vole experiment on islands in lakes
The least weasel attacking field vole Microtus agrestis. Photo Janne Sundell.
A large-scale field experiment on the dynamics of microtine rodents and their main mammalian predator, the least weasel, is being conducted in three experimental islands in lakes in southern and central Finland. The experimental islands, as well
60 as comparable adjacent control islands, are located in Lake Saimaa, Lake Pielinen and Lake Päijänne. Experimental and control islands are 5-10 km2 large and they all include about 1 km2 of primary field vole (Microtus agrestis) habitat, i.e. meadows, old fields and clear cut areas with plenty of hay. The vole population dynamics were studied by live-trappings in primary field vole habitats and biannual snap-trappings in these habitats as well as in forests and clear cuts. The study also involves avian predator and small game censuses. Additions of least weasels, in order to perturb the vole-weasel dynamics, have been started on all islands, and last weasels will be released in late autumn 2000. Some of the released weasels were radio-tracked in order to obtain information about their movements and survival.
Lemming cycles in Northeast Greenland
Northeast Greenland holds one of the simplest vertebrate communities on earth with only one rodent species: the collared lemming. Hence It provides a unique opportunity to investigate the predator-prey interaction, which is hypothesised to control the rodent dynamics. A three-year field program has been organised jointly between the Universities of Helsinki, Montpellier and Freiburg from 1998 to 2000 in order to parameterize and test Hanski & Korpimaki’s (1995) model for the lemming cycles. Other aspects of predator-prey interactions, such as prey selection, have also been studied. The study site is about 75 km² and is located on Traill Island (72°30’ N, 24°00’ W), NE Greenland. This area, part of the high Arctic breeding range of collared lemming, consists of a wide open valley facing the Kong Oscar Fjord. Numerous raised beaches lie parallel to the present shoreline. Inland elevations do not exceed 250 m. above sea level and in contrast to other tundra areas, lakes are scarce and small in size (< 1 ha). Summer is short with only three months without snow cover, and mean summer temperatures do not exceed 5°C. The region has a
61 discontinuous semi-desert polar vegetation. The lemming population dynamics display typical cyclic patterns (4 years) that are also reflected in the densities of predators: arctic fox, stoat, long-tailed skua and snowy owl.
Western part of the Greenland study area at the beginning of June, photo Olivier Gilg.
62 Synopsis of the year 2001
Budget
Funding Source FIM
Academy of Finland Centre-of-excellence funding to MRG 1 477 571 Metapopulation biology 1 470 320 Biodiversity in boreal forests 588 269 Tree canopy insect project 187 992 Stochastic adaptive dynamics of complex systems 231 269
University of Helsinki Centre-of-excellence funding to MRG from Ministry 1 000 000 of Education Salary for a technician 170 000
Ministry of Agriculture and Forestry Biodiversity in boreal forests 700 000
European Commission Survival of species in fragmented landscapes 210 500
Foreign post doc salaries 312 000
TOTAL 6 347 921
Ministry of Environment * 1 000 000 Biodiversity in boreal forests
* managed by the Research Centre of the Friendship Park in Kuhmo
63 Publications
Bélisle, M., and Desrochers, A. 2001. Gap-crossing decisions by forest birds: an empirical basis for parameterizing spatially-explicit, individual-based models. Landscape Ecology, in press.
Bélisle, M., and St. Clair, C. 2001. Cumulative effects of barriers on the movements of forest birds. Conservation Ecology, in press.
Cabeza, M. and Moilanen, A. 2001. Design of reserve networks and the persistence of biodiversity. Trends in Ecology & Evolution 16, 242-247.
Colas, B., Thomas, C.D. and Hanski, I. 2001. Evolutionary responses to landscape fragmentation. In: R. Ferriere, J.H.J. Metz and U. Dieckmann (Eds.), Evolutionary Conservation Biology. Cambridge University Press, Cambridge, in press.
Gu, W.D., Kuusinen, M., Konttinen, T. and Hanski, I. 2001. Spatial patterns in the occurrence of the lichen Lobaria pulmonaria in managed and virgin boreal forests. Ecography 24, 139-150.
Haikola, S., Fortelius, W., O´Hara, R.B., Kuussaari, M., Wahlberg, N., Saccheri, I., Singer, M.C. and Hanski, I. 2001. Inbreeding depression and the maintaenance of genetic load in Melitaea cinxia metapopulations. Conservation Genetics, in press
Hanski, I. 2001. Spatially realistic theory of metapopulation ecology. Naturwissenschaften 88, 372-381.
Hanski, I. 2001. Biology of extinctions in butterfly metapopulations. In: C. Boggs, W. Watt and P. Ehrlich (Eds.), Biology of butterflies. In press.
Hanski, I. 2001. Metapopulation of animals in highly fragmented landscapes and the PVA. In: S.R. Beissinger & D.R. McCullough (Eds.), Population viability analysis. Chicago University Press, in press.
Hanski, I. 2001. Population dynamic consequences of dispersal in local populations and in metapopulation. In: A. Dhont and F. Saunier (Eds.), Evolution of dispersal. Oxford University Press, pp. 283-298.
Hanski, I. 2001. Spatially realistic models of metapopulation dynamics and their implications for ecologiucal, genetic and evolutionary processes. In: J. Silvertown
64 and J. Antonovics (Eds.), Plants stand still, but their genes don’t. Blackwell, in press.
Hanski, I. and Henttonen, H. 2001. Population cycles of small rodents in Fennoscandia. In: A. Berryman (Ed.), Population cycles: Evidence for trophic interactions. Oxford Unviersity Press, in press.
Hanski, I. and Ovaskainen, O. 2001. Extinction dept at extinction threshold. Conservation Biology, in press
Hanski, I. and Singer, M.C. Extinction-colonization dynamics and host plant choice in butterfly metapoluations. American Naturalist 158, 341-353.
Hanski, I., Henttonen, H., Korpimäki, E., Oksanen, L. and Turchin, P. 2001. Small rodent dynamics and predation. Ecology 82, 1505-1520.
Heino, M. and Hanski, I. 2001. Evolution of migration rate in a spatially realistic metapopulation model. American Naturalist 157, 495-511.
Hoffmann, M. P., Ode, P.R., Walker, D.L., Gardner, J., van Nouhuys, S. and Shelton, A.M. 2001 . Performance of Trichogramma ostriniae (Hymenoptera: Trichogrammatidae) reared on factitious hosts including Ostrinia nubilalis (Lepidoptera: Pyralidae). Biological Control 21, 1-10.
Komonen, A. 2001. Structure of insect communities inhabiting old-growth forest specialist bracket fungi. Ecological Entomology 26, 63-75.
Kotze, D. J., Niemelä, J. and Nieminen, M. 2001. Colonisation success of carabid beetles on Baltic islands. - Journal of Biogeography, in press.
Landry, P.-A. and Lapointe, F.-J. 2001. Within-population craniometric variability of insular populations of deer mice, (Peromyscus maniculatus), elucidated by landscape configuration. Oikos, in press.
Lapointe, F.-J. and Landry, P.-A. 2001. A fast procedure for estimating missing distances in incomplete matrices prior to phylogenetic analysis. Pp. 189-190, in Currents Computational Molecular Biology (El-Mabrouk, N., Lengauer. T. & D. Sankoff eds.), Publications CRM, Montréal.
Moilanen, A. 2001. Simulated evolutionary optimization and local search: Introduction and application to tree search. Cladistics 17, 512-525.
65 Moilanen, A. 2001. Suojelualueverkoston suunnittelu matemaattisena ongelmana. Tieteessä tapahtuu 2001 (1), 30-34.
Moilanen, A. ja Cabeza, M. 2001. Single-species dynamic site selection. Ecological Applications, in press.
Moilanen, A. and Nieminen, M. 2001. Simple connectivity measures in spatial ecology. Ecology, in press.
Moilanen, A. and Hanski, I. 2001. On the use of connectivity measures in spatial ecology. Oikos, in press.
Nieminen, M. 2001. Täpläverkkoperhosen metapopulaatio Ahvenanmaalla - populaatiobiologian hiukkaskiihdytin. Tieteessä tapahtuu 2001 (1), 23-29.
Nieminen, M. 2001. Perinnebiotooppien perhoset. Julkaisussa: Perinnebiotooppien monimuotoisuus - Saaristomeren kansallispuiston seminaari 5.3.1998. Metsähallituksen luonnonsuojelujulkaisuja, Sarja A, painossa.
Nieminen, M., Nuorteva, P. and Tulisalo, E. 2001. The effect of heavy metals on the mortality of Parnassius apollo larvae. Journal of Insect Conservation 5, 1-7.
Nieminen, M., Singer, M.C., Fortelius, W, Schöps, K. and Hanski, I. 2001. Experimental confirmation that inbreeding depression increases extinction risk in butterfly populations. American Naturalist 157, 237-244.
Nieminen, M., Leskinen, M. and Helenius, J. 2001. Doppler radar detection of exceptional mass-migrations of aphids into Finland. Journal of Biometeorology, in press. van Nouhuys, S. and Tay, W.T. 2001. Causes and consequences of small population size for a specialist parasitoid wasp. Oecologia 128, 126-133.
Ovaskainen, O. 2001. Mitä teoria sanoo lajien mahdollisuuksista säilyä pirstoutuvassa elinympäristössä?. Tieteessä tapahtuu 2001 (1).
Ovaskainen, O. 2001. The quasi-stationary distribution of the stochastic logistic model. Journal of Applied Probability, in press.
66 Ovaskainen, O. and Hanski, I. 2001. Spatially realistic metapopulation models: global and local assessment of metapopulation capacity. Theoretical Population Biology, in press.
Pakkala, T., Tomppo, E. and Hanski, I. 2001. Spatial ecology of the three-toed woodpecker in managed forest landscapes. Silva Fennica, in press.
Petit, S., Moilanen, A., Hanski, I. and Baguette, M. 2001. Metapopulation dynamics of the bog fritillary butterfly: Movements between habitat patches. Oikos 92, 491-500.
Pitkänen, M. and Roslin, T. 2001. Dung beetles. In: Pitkänen, M. and Tiainen, J. (eds.): Biodiversity of Agricultural Landscapes in Finland. BirdLife Finland Conservation Series (No 3.), Yliopistopaino, Helsinki. pp. 62-70.
Pöyry, J., Wahlberg, N. and Nieminen, M. 2001. Perhosten istutukset lajien suojelussa. Baptria 26, 18-28. [Translocation of Lepidoptera in species conservation]
Roslin, T. 2001. Other mothers' ducklings - why look after them? Trends in Ecology and Evolution 16, 73-74.
Roslin, T. 2001. Inbreeding in nature: brothers and sisters, do not unite! Trends in Ecology and Evolution 16, 225.
Roslin, T. 2001. A letter from the frontier: forecasting species expansions. Trends in Ecology and Evolution 16, 484.
Roslin, T. and Koivunen, A. 2001. Distribution and abundance of dung beetles in fragmented landscapes. Oecologia 127, 69-77.
Roslin, T. 2001. Spatial population structure in a patchily distributed beetle. Molecular Ecology 10, 823-837.
Roslin, T. 2001. Large-scale spatial ecology of dung beetles. Ecography 24, 511- 524.
Rost, M., Várkonyi, G. and Hanski, I. 2001. Patterns of 2-Year Population Cycles in Spatially Extended Host-Parasitoid Systems. Theoretical Population Biology 59, 223-233.
67 Schöps, K. and Hanski, I. 2001. Population-level correlation between pre-alighting and post-alighting host plant preference in the Glanville fritillary butterfly. Ecological Entomology 26, 517-524.
Turchin, P. and Hanski, I. 2001. Contrasting alternative hypotheses about rodent cycles by translating them into parameterized models. Ecology Letters 4, 267-276.
Várkonyi, G. and Ahola, M. 2001. Notes on the larval biology of Xestia borealis (Lepidoptera, Noctuidae). Entomol. Fennica 12 (2), 78-80.
Wahlberg, N. 2001: The phylogenetics and biochemistry of host plant specialization in melitaeine butterflies (Lepidoptera: Nymphalidae). Evolution 55, 522-537
Wahlberg, N. 2001: On the status of the scarce fritillary Euphydryas maturna (Lepidoptera: Nymphalidae) in Finland. Entomologica Fennica 12, in press.
Wahlberg, N., Klemetti, T., Selonen, V. and Hanski, I. 2001: Metapopulation structure and movements in five species of checkerspot butterflies. Oecologia, in press
Wahlberg, N., Kullberg, J. and Hanski, I. 2001: Natural history of some Siberian melitaeine butterfly species (Nymphalidae: Melitaeini) and their parasitoids. Entomologica Fennica 12, in press.
Theses
Anne Koivunen, MSc: The structure of dung beetle communities in a decreasing network of cattle farms
The number of cattle farms has declined drastically in Finland during the last 40 years. The fragmentation of agricultural landscape can have serious effects on many insects groups. In my thesis I studied dung beetles beloging to a genus Aphodius. One of my most important goals was to investigate if the etapopulation consept could be applied to studies of population dynamics of the dung beetles. I also studied how the agricultural landscape structure affects the Aphodius communities. I investigated how the number of cattle, cattle history and farm connectivity affects dung beetles. My study area was in western Uusimaa because the cattle farm network is quite sparse there. 47 farms were studied.
68 Both the number of individuals and species varied considerably between different farms. However farm connectivity, cattle history and the number of cattle affected only the distribution of five species and only the number of individuals of one species The results were not what could have been expected according to the metapopulation theory. It seems highly probable that the metapopulation processes do not have any significant influence on most dung beetle species. It is possible that there is no single model that could explain the distribution of the dung beetles in fragmented landscapes.
External visits
Ilkka Hanski, Saskya van Nouhuys, Juha Siitonen (Forest Research Institute), Yo- cheng Dai (Department of Ecology and Systematics), Jaakko Kullberg (Natural History Museum) and Marcin Zalewski visited the Orenburg region and Bashkiria in southern Russia in June and August to sample species for the boreal forest biodiversity project and the checkerspot butterfly project.
Mar Cabeza visit Professor Hugh Possinghams lab at the Departments of Zoology and Mathematics, University of Queensland, St Lucia, Australia. October 3rd-16th.
Otso Ovaskainen visited Bryan Grenfell’s group in the University of Cambridge for August 2001-August 2002.
Seminars, lectures and talks
Marc Bélisle, & C. St. Clair gave a talk "Cumulative effects of barriers on the movements of forest birds" In AOU 2001. 119th Meeting of the American Ornithologists' Union. Seattle, Washington, USA. 14-18 August 2001.
Marc Bélisle gave an invited talk "Should I stay or should I go? Gap-crossing decisions of forest birds moving in fragmented landscapes" In Ecology Seminar of the Department of Ecology and Systematics. University of Helsinki, Helsinki, Finland. 21 March 2001.
Mar Cabeza gave a talk "Long-term performance of reserve-network design methods: considering habitat loss" at the post graduate student seminar at the Department of Ecology and Systematics, University of Helsinki, Finland. April 16th.
69 Mar Cabeza gave a talk "Design of reserve networks and the persistence of biodiversity" at the 2001 Society for Conservation Biology Annual Meeting. July 29th-August 2nd.
Mar Cabeza participate in a working group organized by CABS (Center for Applied Biodiversity Science, Conservation International) on Reserve Selection and Climate Change, in Brisbane, Australia. October 7th-12th.
Oscar Gaggiotti gave a talk "Patterns of colonisation in a grey seal metapopulation" in the eight congress of the European society for evolutionary biology in Århus, Denmark, in 20-25 August 2001.
Sari Haikola presented a poster "Does inbreeding depression leed to avoidance of sib-mating in Melitaea cinxia?" in Leeds.
Ilkka Hanski gave invited seminars in the biology departments in the State University of Utah, the Cornell University and the University of Minnesota in March.
Ilkka Hanski gave an invited seminar in the Department of Biology, University of Amsterdam, in April.
Ilkka Hanski was an invited speaker in the British Ecological Society Annual Meeting in Birmingham in January.
Paavo Hellstedt presented a poster "Impact of Stoats (Mustela erminea) on the Small Mammal Community Dynamics Change in Finnish Lapland, Hellstedt, P. & Henttonen, H." in the International Theriological Congress 8 (ITC8), in Sun City, South Africa, in August 2001.
Maaria Kankare gave a talk "Population genetics of the Melitaea cinxia parasitoids" in the meeting of PhD students in Evolutionary Biology; 21- 25.3.2001; Bernried, Germany.
Maaria Kankare gave a talk "Population genetics of the Melitaea cinxia parasitoids" in the Spring Symposium; 4-6.4.2001; Helsinki, Finland.
Maaria Kankare gave a talk "Molecular phylogeny of Cotesia parasitoids associated with melitaeine butterflies" in the XIII Entomophagous Insects Workshop; 24-28.9.2001; Delaware, USA.
70 Anna-Liisa Laine presented a poster "Species interactions and the resulting spatial pattern in a fragmented landscape" in Leeds.
Anna-Liisa Laine gave a talk "Species interactions and the resulting spatial pattern in a fragmented landscape" in Spring Symposium at the Department of Ecology and Systematics, University of Helsinki, Finland.
Anna-Liisa Laine attented the four weeks cource on "Plant Disease in Natural Systems" at the University of Virginia, USA.
Atte Moilanen gave a talk "Analysing metapopulation dynamics: SPOMSIM - a stochastic patch occupancy model simulator" in Leeds.
Atte Moilanen gave a talk "Implications of empirical data quality to metapopulation model parameter estimation and application" in Leeds.
Atte Moilanen attented the meeting "Society for Conservation Biology 15th Annual Meeting" in Hilo, Hawaii 29th July-1st.August.
Atte Moilanen gave a Workshop "Stochastic patch occupancy models of metapopulation dynamics: Introduction and application to conservation"
Marko Nieminen gave a talk "Täpläverkkoperhosen metapopulaatio Ahvenanmaalla - populaatioekologien hiukkaskiihdytin" in Tieteen päivät 2001, Helsinki, January 2001.
Marko Nieminen gave a talk "Miksi perhoset vaeltavat?" in Hyönteistieteellisten seurojen yhteiskokous, Tampere, February 2001.
Marko Nieminen gave a talk "Täpläverkkoperhosen metapopulaatio Ahvenanmaalla - populaatioekologien hiukkaskiihdytin" in Ympäristöhallinnon koulutustilaisuus, Helsinki, March 2001.
Marko Nieminen gave a talk "Täpläverkkoperhosen (Melitaea cinxia) populaatiobiologiasta" in Vanamon ja Societas pro Fauna et Flora Fennican yhteiskokoukses, Helsinki, March 2001.
Marko Nieminen, Saskya van Nouhuys and Mike Singer gave a talk "Larval performance and suitability of host plants in Melitaea cinxia" in TMR-meeting in Leeds, England.
71 Marko Nieminen, Ilkka Hanski, C. Breuker & K. Schöps presented a poster "Population history and oviposition preference affect the migration rate of female Melitaea cinxia butterflies" in BES meeting in Reading, England.
Saskya van Nouhuys gave a seminar "Colonization pattern of a butterfly and two specific parasitoids in a fragmented landscape"at the XIII International Entomophagous Insect workshop in Delaware. September 2001.
Saskya van Nouhuys gave a seminar "Large-scale population dynamics and multitrophic level interactions of a parasitoid wasp" to the Netherlands Institute of Ecology. April 2001.
Bob O´Hara gave an invited talk "Ignorance, and Ignorance about Ignorance: Bayesian approaches to modelling the occurrence of species" at a workshop in Uppsala entitled "Modelling - Prediction and Analysis of Biodiversity".
Bob O´Hara gave an invited talk "Lichen in Random Fields" at a workshop in Uppsala entitled "Modelling - Prediction and Analysis of Biodiversity".
Bob O´Hara gave a talk "Leptokurtosis: Identification and Identifiability" in Leeds.
Bob O´Hara gave a talk "Explaining Distributions and Abundances of Carabid Beetles, as well as the behaviour of Dutch beetle collectors" at a Combi (Computational Biology Graduate School) meeting, 29th August.
Otso Ovaskainen gave a talk "Mitä teoria sanoo lajien mahdollisuuksista säilyä pirstoutuvassa elinympäristössä?" in Tieteen päivät 2001, Helsinki, 13th January 2001.
Otso Ovaskainen gave a talk "Mitä teoria sanoo lajien mahdollisuuksista säilyä pirstoutuvassa elinympäristössä?" in FEI seminar "Elinympäristöjen pirstoutuminen – suojelubiologisia tutkimustuloksia" in Helsinki, 3rd March 2001.
Otso Ovaskainen gave a talk "Extinction debt at extinction threshold" in Fragland meeting in Leeds, 30th March 2001.
Otso Ovaskainen gave a talk "Metapopulation dynamics in fragmented landscapes" at the University College, London. 14th October 2001.
72 Otso Ovaskainen attented the program "From Individual to Collective Behaviour in Biological Systems" arranged by the Isaac Newton Institute for Mathematical Sciences" in Cambridge. 29th October - 14th December 2001.
Otso Ovaskainen attented the workshop "The mathematics of social insects" arranged by the Isaac Newton Institute for Mathematical Sciences" in Cambridge 7th-8th December 2001.
Otso Ovaskainen attented the workshop "Immunology, ecology and epidemiology" arranged by the Isaac Newton Institute for Mathematical Sciences" in Cambridge 10th-14th December 2001.
Tomas Roslin attented TMR Fragland meeting in Leeds, England.
Tomas Roslin presented a poster "Dispersal in the dung beetle Aphodius fossor" in the British Ecological Society Annual Symposium 2001, Dispersal. University of Reading, UK. April 3-5 2001.
Tomas Roslin gave a talk "Suomen kovakuoriaislajiston muutokset: Lantiaiset." [Recent changes in the Finnish beetle fauna: Dung beetles.] in Suomen WWF:n kovakuoriaistyöryhmän 10-vuotisjuhlaseminaari. Suomen Ympäristökeskus, Helsinki, May 7, 2001.
Tarja Salmi attented the meeting GIS and spatial modeling (Catholic University of Louvain, Louvain-la Neuve, 8th-11th January, 2001.
Mika Siljander attented the Fragland Workshop "GIS applications & landscape modelling", Louvain-la-neuve Belgium 12-13 January 2001.
Mika Siljander gave a talk "Lanscape analysis using Arc View Patch Analyst & Fragstats 2.0" in the Fragland Workshop GIS applications & landscape modelling, Louvain-la-neuve Belgium 12 January 2001.
Mika Siljander gave a talk "Using Arc View GIS in ecological research: building GIS database for Glanville fritillary (Melitaea cinxia)" in the Fragland Workshop GIS applications & landscape modelling, Louvain-la-neuve Belgium 12 January 2001.
Janne Sundell presented a poster "Population dynamics of microtine rodents: an experimental test of the predation hypothesis" in 8th International Theriological Congress in Sun City, South Africa at 12-17 August 2001.
73 Leena Suvanto presented a poster "Clone identification using microsatellites in Populus tremula" in the eight congress of the European society for evolutionary biology in Århus, Denmark, in 20-25 August 2001.
Gergely Várkonyi gave a talk "Dispersal behaviour of boreal Xestia moths in old- growth forest corridors" in TMR meeting in Leeds, England, 28 March - 2 April.
Gergely Várkonyi presented a poster "Dispersal behaviour of boreal Xestia moths in old-growth forest corridors" (Gergely Várkonyi, Mikko Kuussaari & Harri Lappalainen) in BES meeting on Dispersal, Reading, England, 3-5 April.
Gergely Várkonyi gave a talk "Host-parasitoid dynamics drive periodic occurrence of boreal moths" in Spring Symposium, Helsinki, Finland, 4-6 April.
Gergely Várkonyi gave a talk "Host-parasitoid dynamics drive periodic occurrence of boreal moths" in Parasitoid Hymenoptera: Taxonomy and Biological Control 14-17 May 2001, Köszeg, Hungary.
Gergely Várkonyi gave a talk "Host-parasitoid dynamics drive periodic occurrence of boreal moths" in XIII Entomophagous Insect Workshop, 23-27 September 2001, University of Delaware, USA.
Gergely Várkonyi attented the meeting Ecosystem Management in Boreal Forest Landscapes, Koli National Park, Finland, 27-30 May 2001.
TV, radio and newspapers
Tapio Gustafsson, interview on the effects of global warming on arctic fish populations, Etelä-Suomen Sanomat, October 20th 2001. (ed. Ilpo Kekki).
Ilkka Hanski, MTV3 Akatemia, a lecture, in December 2000.
Otso Ovaskainen, "Kuudes aalto: puolet lajistosta kuolee", Helsingin Sanomat, 13th January 2001.
74 Tomas Roslin, interview on dung beetle biology, YLE TV1, August 29 2001. (Luonnossa, eds. Juha Laaksonen and Minna Pyykkö).
Tomas Roslin, interview on dung beetle biology, YLE Radio Suomi, August 19 2001 (Luontoretki, ed. Juha Laaksonen).
Tomas Roslin, interview on bird biology, YLE Radio Vega Mellannyland, April 25 2001 (ed. Carmela Walder).
Tarja Salmi and Leena Suvanto, interview on Aspen biology, "Helsingin yliopisto tutkii haavan leviämistä Kuhmossa", Kuhmolainen 21.6.2001 (ed. Martti Huusko).
Teaching and courses
The Ultimate Course on CONSERVATION BIOLOGY IN FRAGMENTED LANDSCAPES (1-6 SW)
This course will give basic knowledge of the spatial structure and dynamics of fragmented populations. We aim for an interesting blend of theory and empirical case studies, and will put particular emphasis on the application of metapopulation theory to practical conservation issues. The lectures are given by young researchers active in the Metapopulation Research Group.
The course consists of several units:
1) Lecture series (1 sw) coordinated by Roslin, Nieminen and Moilanen, see below.
2) Seminar on "Conservation Biology in Fragmented Landscapes" (1 sw) coordinated by Roslin, Nieminen and Moilanen. Two days of student presentations at the Lammi Biological Station.
3) Seminar on "Biodiversity in Boreal Forests" (1 sw) coordinated by Ovaskainen Two days of student presentations at the Lammi Biological Station.
4) Book exam (2 sw) Hanski, I. 1999. Metapopulation Ecology. Oxford University Press (with some complementary material). Coordinated by Roslin, Nieminen and Moilanen.
5) Practicals (1 sw)
75 Simulations, essays etc., based on personal agreement with the lecturers. Organized by the lecturers.
LECTURES ON CONSERVATION BIOLOGY IN FRAGMENTED LANDSCAPES
1. General introduction: Habitat loss, fragmentation and species extinction (Roslin)
2. Animal movement in fragmented landscapes (Belisle)
3. Extinctions: causes and patterns (Nieminen)
4. Population genetics of fragmented populations (Landry)
5. Empirical case studies I: Melitaea cinxia (Nieminen)
6. Metapopulation concepts and modeling (Moilanen)
7. Empirical case studies II: Fragmented boreal forests (Várkonyi)
8. Practical metapopulation modeling; Habitat loss, the extinction debt and the delay to extinction (Moilanen)
9. Empirical case studies III: Multiple species in fragmented landscapes (Roslin)
10. The selection of natural reserves I: Introduction (Cabeza-Jaimejuan)
11. The selection of natural reserves II: Site selection algorithms (Cabeza- Jaimejuan)
12. Conclusions and prospects for the future (Hanski)
OTHERS
Marc Bélisle gave a lecture "Applications of spatially-explicit, individual-based models in ecology" within the graduate course Spatio-temporal Modelling. Turku University, Department of Geography, Finland.
76 Tapio Gustafsson, instructor at the field course on "Subarctic Ecology" in the Kilpisjärvi Biological Station (University of Helsinki), 26th June – 5th July 2001.
Paavo Hellstedt, a lecture in the course of "Animal identification". Dept. of Ecology & Systematics, University of Helsinki.
Paavo Hellstedt, the leader of the "Ecology and behaviour of carnivores" seminar. Dept. of Ecology & Systematics, University of Helsinki.
Paavo Hellstedt, a teacher at the field course and seminar of "Ecology of mammals". Dept. of Ecology & Systematics, University of Helsinki.
Paavo Hellstedt, a leading teacher at the field course of "Ecology". Dept. of Ecology & Systematics, University of Helsinki.
Gergely Várkonyi , teacher on the field course on "Taxonomy and Ecology of Terrestrial Animals" of the University of Oulu, 7-16 August 2001, Oulanka Biological Station, Finland.
Gergely Várkonyi attanding the MRG course on Conservation Biology in Fragmented Landscapes as a teacher on 13-14 October 2001 in Lammi Biological Station (Seminar on "Biodiversity in Boreal Forests") and 16 October 2001 in Helsinki, as the lecturer of "Empirical case studies I: Fragmented boreal forests".
Honors and awards
Ilkka Hanski was elected a Member of the Finnish Academy of Science and letters.
Ilkka Hanski was awarded The Sewall Wright Award of the American Society of Naturalists.
Anna-Liisa Laine was awarded the Prize for the best presentation at The Spring Symposium at the Department of Ecology and Systematics, University of Helsinki, Finland.
Council Memberships
Ilkka Hanski has served in the Scientific Advisory Board of the University of Helsinki, Finland.
77 Ilkka Hanski has been a board member in the E.J. Sariola Foundation, Finland, and the Finnish Cultural Foundation.
Meetings organized by the MRG
Annual Meeting of the MRG in Saaremaa, Estonia, in April.
Fragland (TMR) Annual Meeting in Leeds, UK.
Prof. Paul Ehrlich, Dr. Carol Boggs and Dr. Jessica Hellmann visited the MRG during 3 days in September to work on the planned book on checkerspot butterflies, which presents a synthesis of the long-term research conducted on Euphydryas editha in Stanford and Melitaea cinxia in Helsinki.
Visitors to the MRG
Rampel Etienne, collaborative research, April and May 2001.
Porf. Hugh Possingham, University of Queensland, collaborative research, May 2001.
Wenxi Yu, August and September 2001. Zhang Hanguo, August and September 2001. Hui Changlin, August and September 2001. Xu Cunbao, August and September 2001. Zhang Chenglin, August and September 2001.
Dr. Jessica Hellman, checkerspot book, September 2001. Dr. Carol Boggs, checkerspot book, September 2001. Prof. Paul Ehrlich, checkerspot book, September 2001.
Miguel Araújo, Centre d'Ecologie Fonctionnelle et Evolutive, Montpellier, collaborative research, September 1-31st.
Monique Poulin, collaborative research, Département de Phytologie, Université Laval.
78 Prospects for the year 2002
What should one expect, or wish, to happen in a research group following an active and successful year? More of the same? Yes, though with the difference that projects that were not amongst the most visible ones in 2001 should take the front stage in 2002. More celebrations? Yes, as several students are expected to finish their studies in 2002. The forest biodiversity project and the European Commission funded Fragland network are coming to an end, and we have to look for ways of replacing them. The Melitaea cinxia project also enters a new stage. With the re- description of the Åland landscape, from the butterfly's perspective, having finally been completed in 2001, it is now time to set new goals for the research, including further integration of genetic and evolutionary studies into the existing ecological research, and further expansion of modelling. The checkerspot book that some of us are now busily writing should be completed in 2002, though our readers probably have to wait until 2003. The shrew project enters its second year, after which we should know how much potential there actually is in it. One important change that will affect all of us is the move of the entire department to the Viikki campus, which is expected to take place in March. I look forward to this move and the new academic setting with many other large research groups in the biological sciences.
Ilkka Hanski
79 Typical Melitaea cinxia habitat patch in the Åland Islands.
80