Metapopulation Research Group
University of Helsinki Annual Report 1999
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 was designed by Gergely Várkonyi
2 Contents
Preface … 5
Brief history and overview of the MRG … 6
Scientific highlights of 1999 … 8
Structure of the MRG … 14
MRG personnel; research interests … 18
Laboratory facilities … 28 Helsinki Tvärminne Lammi
Field sites … 30 Åland Islands Kuhmo Central Finland Lammi Kilpisjärvi
Synopsis of the year 1999 … 34 Budget Publications Theses External visits Seminars, lectures and talks Honors and awards Council Memberships Meetings organized by the MRG Visitors to the MRG
Prospects for the year 2000 … 45
3 The Glanville fritillary butterfly (Melitaea cinxia) in the Åland Islands.
Habitat patches in the Åland Islands; white dots are empty patches and black dots are occupied patches in the autumn 1999 survey.
4 Preface
Successful organizations tend to go through cycles of expansion and consolidation. In the Metapopulation Research Group, 1999 was a year of consolidation: the infrastructure of the research group was strengthened and we were getting ready for the year 2000 and for our new position as one of the centres-of-excellence in research chosen by the Academy of Finland. This does not mean that 1999 was stagnant scientifically. The reason for emphasizing the broader issues here is the qualitative shift that is under way in the MRG. We are becoming well established. Research activities spread along three dimensions in 1999. The hard core of the MRG is located in one place in the Department of Ecology and Systematics at the University of Helsinki, allowing for constant interaction in our weekly seminars, during daily coffee breaks, and whilst sharing crowded offices. The three more permanent research teams into which the MRG is currently structured - the Metapopulation Modelling Team, the Melitaea cinxia Team and the Molecular Ecology Team - are all placed here. The level of interaction is so high that we do not easily perceive the three teams as such. The national outreach of the MRG has been the large-scale Old-growth forest project, funded by the Finnish Biodiversity Research Programme, the Ministry of Forestry and Agriculture and the Ministry of Environment. In the course of this project, our research has spread to other locations in Finland, especially to the Research Centre of the Friendship National Park in Kuhmo, central-eastern Finland. We have had visibility in the national press through our involvement in current forest conservation issues. Finally, the EC-funded Training and Mobility of Researchers network Fragland, which is coordinated by the MRG, renders the most conspicuous international link, with several workshops and meetings arranged in 1999, and with several visits by students and post docs between the MRG and the six other European research groups involved in Fragland. I am particularly pleased with the pleasant yet intellectually challenging international atmosphere that we have in the MRG, to which all students, post docs, research assistants and technicians have contributed. It has been rewarding to work in the Metapopulation Research Group in 1999.
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 structure within populations, 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.
The figure below illustrates the growth of the MRG since 1992:
12 Post graduate students Post docs 10
8
6
4 Number of individuals 2
0 1992 1994 1996 1998 2000 Year
Currently there are 11 post graduate students and 9 post docs in the MRG, representing 8 different nationalities.
6 Until recently, the MRG has functioned as a single research group with only one senior researcher with a permanent position (Hanski). At present, the MRG is evolving into a more complex structure, with three distinct research teams (Metapopulation Modelling Team, The Glanville fritillary Team, and the Molecular Ecology Team), three projects of fixed duration (Old-growth forest biodiversity, small mammal population dynamics, and forest canopy insect dynamics), and one EC-funded TMR network coordinated by the MRG (Fragland). A more detailed description of the structure of the MRG is presented on page 14.
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 7 other academic staff. Despite its small size the DPB has performed well in recent years, as is indicated by its status as one of the centres-of-excellence in research selected by the Ministry of Education for the years 1997-99. The MRG has had an influence on the general direction of research in the DPB, which is now broadly 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 metapopulation dynamics (especially the incidence function model and related models) and a large-scale empirical research project on a species of butterfly, the Glanville fritillary (Melitaea cinxia). The latter started as an ecological project but has 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 frame work 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.
Scientific highlights of 1999
“Metapopulation Ecology”, by Ilkka Hanski, published by the Oxford University Press in 1999
This is the current synthesis of my favourite approach to metapopulation ecology, covering the basic ecological models and reviewing a range of empirical studies. A third section in the book is focused on the Glanville fritillary butterfly, “to demonstrate the value of the metapopulation approach as described in the two earlier parts of the book” - and to make justice to the hard work that many past and present members of the MRG have done on this wonderful species! The incidence function model plays a big role, of course, in this book. Writing a synthesis of a rapidly moving field has the drawback that parts of the text are somewhat outdated already at the date of publication. The modelling work conducted in the MRG in 1999 has produced important new results that will feature prominently in the second edition.
Expansion of the field work on the Glanville fritillary, by Marko Nieminen
The large-scale monitoring of the Glanville fritillary (Melitaea cinxia) metapopulation in Åland Islands in SW Finland started in 1993, when all the land area was surveyed for habitat patches suitable for the butterefly. This survey yielded ca 1500 suitable habitat patches. Habitat suitability is primarily on the occurrence of one or both of the larval host plants Plantago lanceolata and Veronica spicata. The first population monitoring took place in the autumn 1993,
8 when all known patches were examined for the presence of larval groups. In the following spring, all patches occupied in the previous autumn were visited again, and the numbers of larval groups and larvae, and the numbers of cocoons of the specialist parasitoid wasp Cotesia melitaearum were counted. Since the first monitoring the list of patch attributes to be recorded has somewhat increased, but otherwise the monitoring has been carried out with similar methods. However, as numerous new habitat patches were found in each autumn and spring, the number of patches had increased up to ca 1650 by the autumn 1997. At the same time, it had become evident that some areas were poorly surveyed in 1993 and all areas still contained new patches to be found. New patches are being created by changes in land-use practices, but mostly the “new” patches had been there throughout the study period. We concluded that there was an urgent need for a more exhaustive landscape survey and decided to run a re- survey of the entire Åland Islands. In the early summer 1998, two people started to systematically go through all the sites potentially inhabited by the larval host plants. Potential sites (mainly rocky outcrops) are primarily located next to cultivated fields, pastures and other areas under human influence. Almost half of the land area was covered in 1998 and the number of habitat patches increased to ca 3100. The re-survey was completed in 1999. Now the number of patches is 4550, of which ca 350 are situated on islands without the Glanville fritillary. The first landscape survey was actually not as poor as it might appear from the numbers presented above, as the expanded habitat patch network includes plenty of very small and ephemeral patches. This is clearly demonstrated by the significantly lower occupancy rate of the butterfly in the new than old patches in 1998 and 1999. Thus, in most of the Åland Islands only a couple of new good- quality patches were found and the first survey produced a reasonably accurate picture of all the patches. In contrast, some areas were originally poorly surveyed, and it is in these areas where re-analyses of habitat patch occupancy and related processes can potentially lead to somewhat different results, which needs to be analysed in the future. There are still two sub-types of habitat patches which are not completely covered in our habitat patch network: dry meadows in open rocky places away from cultural areas and rocky shore-meadows. The former ones are most numerous in the northwestern part of Åland, but the latter ones may occur more widely along the shoreline. The locations of these habitat types will be examined after summer 2000, when the entire Åland Islands will be covered with high resolution aerial photographs.
9 Host-parasitoid research in Åland, by Saskya van Nouhuys
In the Åland Islands there are two primary parasitoids and several hyperparasitoids that have significant ecological impact on one another and on the Glanville fritillary butterfly. In 1999 we worked on four different ecological studies of these parasitoids. First, we continued a yearly intensive spring survey of the primary parasitoid Cotesia melitaearum in the entire Åland Islands. We are using this large- scale parasitoid survey for analysis of local parasitoid extinctions and colonizations, and it will be used for the modelling of host-parasitoid dynamics. By repeatedly visiting all of the populations found we can analyse the causes of mortality in extremely small and extinction prone populations and are continuing an ongoing study of the seasonal synchrony between the adult stage of the parasitoid and the susceptible stage of the host larvae. Second, we have conducted several experiments addressing the ecological interactions between the parasitoids. We found that the parasitoid species that seems to be the superior competitor as an adult is an inferior competitor as an immature within the host. We also conducted a successful experimental test of the theory of apparent competition between parasitoids mediated by a shared hyperparasitoid. We completed two small experiments began in 1998, one measuring the dispersal distances of parasitoids in the field and the other one comparing the rate of parasitism between host in different habitat types. Third, we began a study of the influence of defensive plant secondary compounds on the searching behaviour of the specialist parasitoid C. melitaearum. Preliminary results suggest that the parasitoid is attracted to the plant secondary compounds, which are sequestered by the feeding host larvae probably as a defence against predation and parasitism. Finally we continued to collect and analyse samples for a study of the genetic structure of the primary parasitoid and hyperparasitoid populations in the Åland Islands. In addition we initiated a detailed study of the relatedness between individuals within and among populations using markers amplified from DNA extracted from the abandoned silken parasitoid cocoons of C. melitaearum. This latter project is done in conjunction with a laboratory study of the effect of sib- mating on fecundity and the progeny sex ratio.
Metapopulation capacity ȜM , by Otso Ovaskainen
Two components of metapopulation capacity measure the capacity of a habitat patch network to support a viable metapopulation. First, the metapopulation persistence capacity ȜM defines the threshold condition for long-term persistence as ȜM!į, where į is a parameter set by the extinction and colonization rate parameters of the focal species. Second, the metapopulation invasion capacity ȜI sets the
10 condition for succesful invasion of an empty network from one small local population as ȜI!į. Mathematically, the persistence condition corresponds to the existence of a stable non-trivial equilibrium state, whereas the invasion condition is valid when the trivial equilibrium state corresponding to metapopulation extinction is unstable. Based on these measures, deterministic continuous-time and discrete-time models can be classified to three categories. The first category consists of Levins- type models, for which the two measures coincide and are given by the leading eigenvalue of an appropriate ‘landscape’ matrix characterizing the habitat patch network. The two other categories consist of models possessing either a strong or a weak metapopulation-level Allee effect, meaning that although the species could persist in the habitat patch network, a single small local population cannot invade an empty network. In other words, the abundance of the species has to exceed a threshold level before invasion is possible. The metapopulation-dynamic significance of an individual habitat patch q can be assessed by the quantities ȜM,q and ȜI,q, measuring the decrease in the metapopulation capacities ȜM and ȜI due to the removal of patch q from the network. These local measures are given by the elements of the leading eigenvector or comparable quantities, and they can conveniently be extended to ask about the dynamic significance of possible new patches that could be added to specific locations in the landscape.
Evolution of migration rate, by Mikko Heino
We have developed an individual-based metapopulation model to study the evolution of migration rate (M. Heino & I. Hanski, Evolution of migration rate in a spatially realistic metapopulation model, submitted). The wealth of information available on Melitaea cinxia and Melitaea diamina provides an unique opportunity to rigorously estimate most of the parameters of a detailed and realistic individual- based model. We apply the model to the real habitat patch networks occupied by M. diamina in the Tampere region and M. cinxia in Åland Islands in Finland. In M. diamina, the model-predicted migration rate is not significantly different from the empirically observed one. In both species, regional variation in the patch areas and connectivities leads to different local optima in the migration rate. Predictions on such differences can be quantitatively tested with appropriate empirical data. To gain better understanding on the behaviour of the model, and to get insight to some more general questions, we have also studied evolution of migration in hypothetical patch networks on regular lattice. In particular, we have obtained interesting results on the evolution of migration rate in populations inhabiting deteriorating landscapes. If the primary consequence of habitat change is to increase local extinction risk due to decreased local population sizes (either
11 because of reduction of patch sizes, or because of decrease in patch quality), the evolutionary response is increased migration rate. If the quality of the matrix habitat deteriorates, leading to increased mortality during migration, the evolutionary response is more complex. As long as habitat patch occupancy does not decrease markedly with increased migration mortality, reduced migration rate evolves. However, once mortality becomes so high that empty patches remain uncolonized for a long time, evolution tends to increase migration rate, which may lead to an 'evolutionary rescue' in a fragmented landscape, in other words, a metapopulation with an evolving migration rate may persist while a metapopulation with a fixed migration rate would go extinct. At present, the model assumes that reproduction is clonal, migration is unconditional, and migration rate is the only evolving trait. Relaxing these assumptions will allow us to address new question on, e.g., co-evolution of host plant usa and migration patterns, and evolution of migration rate in sexually reproducing populations subject to inbreeding depression.
A field experiment on the evolution of migration rate, by Ilkka Hanski
A field experiment was conducted in the summer of 1999 on the Glanville fritillary in Åland Islands to study the evolution of migration rate. We reared, marked and released butterflies originating from four regions into a common fragmented landscape in the island of Vårdö in eastern Åland, where the Glanville fritillary does not occur naturally. The four experimental 'populations' included three regions in Åland, two of which have dense and one of which has a sparse network of habitat patches for the butterfly. The fourth population was from Estonia, from one large continuous population. The purpose of the experiment is to find out whether the movement patterns of butterflies from the four regions are different under the same environmental conditions. If yes, the differences might be due to adaptations to more or less fragmented landscapes. All three populations from Åland consist of individuals coming from newly-established versus older small local populations, thus allowing a comparison between the offspring of immigrant females (which had established a new population in 1998) and (mostly) resident females (from the older local populations). The results of this experiment have not been analysed by the end of 1999.
Melitaeini phylogeny, by Niklas Wahlberg
A molecular phylogeny of the tribe Melitaeini (Lepidoptera: Nymphalidae) was completed in 1999 and a manuscript has been submitted for publication. This work has been done in cooperation with Marie Zimmermann from the University of Marseille, France. The molecular phylogeny is based on mitochondrial DNA
12 sequences of 77 species of Melitaeini. Two genes were sequenced, cytochrome oxidase subunit I (COI, 1422 bp) and the 16S ribosomal RNA gene (536 bp). The cladogram was constructed using cladistic methods. The main results are that there are four distinct groups in Melitaeini: the Euphydryas group, the Phyciodes group, the Chlosyne group and the Melitaea group. Based on the phylogenetic hypothesis the tribe has originated in the Nearctic region, where the most basal species of each group are found. The Phyciodes group and the Chlosyne group have both colonized the Neotropics independently. The Euphydryas group and the Melitaea group have both colonized the Palaearctic region independently.
Research on Xestia moths, by Gergely Várkonyi
Species of Xestia (Noctuidae) with a two-year life cycle are widely distributed in the boreal forests of the Holarctic Region. Adults of the congeneric moth species emerge synchronously in large numbers every second year (common cohort), whereas in alternate years adults are uncommon (rare cohort). This striking periodic occurrence seems to be constant in time in a particular locality as well as spatially throughout large geographical areas. Finnish Lapland is unique for studying Xestia, as there is a border between the ”eastern” and the ”western” occurrence patterns, with odd-year and even-year common cohorts respectively. We have found strong evidence suggesting that periodicity in Xestia is due to interaction with a parasitoid wasp, Ophion luteus. Predictions of a mathematical model are consistent with the empirical results. Papers on the host- parasitoid interaction in northern Xestia and on a spatially extended model are in preparation. A further goal of our research is to describe the parasitoid assemblage attacking Xestia larvae. Molecular markers have been used to quantify the amount of gene flow between the two coexisting cohorts in one locality and between cohorts in separate geographical areas in Xestia tecta. The overall low level of genetic differentiation that has been found can be explained by substantial gene flow or by a recent common ancestor of all the cohorts. By marking and recapturing Xestia moths, we have studied their dispersal ability in Kuhmo in a heavily managed landscape, where only stripes and patches of old-growth forest have been left. Both the habitat generalist species X. speciosa and the strictly old- growth forest specialist species X. rhaetica preferred corridors for dispersal, but they also were able to cross wide (500 m) belts of sapling stands, suggesting that larval biology of X. rhaetica – rather than adult behaviour – is restricting its occurrence to old-growth forests.
13 Structure of the MRG
The chart below gives an impression of the structure of the MRG and how the different teams and current projects relate to each other. The table on the following page lists the names of the people involved.
TMR Network Fragland *
The core MRG Melitaea cinxiaTeam
Metapopulation Molecular Ecology Team Modelling Team
Boreal Forest Biodiversity Project
Tree Canopy Insects Project Small Mammal Project
* 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)
14 Metapopulation Research Group, personnel
Ilkka Hanski, Director Tapio Gustafsson, Research secretary Anu Väisänen, Research secretary
Leader Post docs Post Grad students Technicians ————————————————————————————————————————— Melitaea Marko Nieminen Katrin Schöps cinxia Saskya van Nouhuys Team Niklas Wahlberg Sari Haikola Riitta Rantala Mika Siljander ————————————————————————————————————————— Metapopulation Atte Moilanen Steve Matter Modelling Otso Ovaskainen Team Mar Cabeza Nathalie Jarosz ————————————————————————————————————————— Molecular Jodie Painter Maaria Kankare Ecology Tomas Roslin (until 31.8.) Team Rongjiang Wang —————————————————————————————————————————
————————————————————————————————————————— Forest Ilkka Hanski Weidong Gu Biodiversity Laura Kivistö Project Atte Komonen Reijo Penttilä Gergely Várkonyi ————————————————————————————————————————— Small Ilkka Hanski Olivier Gilg Mammal Paavo Hellstedt Project Janne Sundell Heikki Eerola ————————————————————————————————————————— Tree Ilkka Hanski Tomas Roslin (1.9. onwards) Canopy Insects Project ————————————————————————————————————————— TMR Ilkka Hanski Bob O´Hara Network Rosemary Setchfield Fragland —————————————————————————————————————————
15 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 empirical project in the MRG. The Melitaea cinxia project has produced several PhD and Msc theses and a large number of publications in top international journals, including Nature and Science. The empirical studies are often closely related to metapopulation modelling. The large-scale monitoring of hundreds of local populations in the Åland Islands was started in 1993 and will be continued at least until 2005.
Metapopulation Modelling Team
The research in the Metapopulation Modelling Team has been focused on ecological models of metapopulation dynamics, including both analytical models that can be analysed mathematically and stochastic 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 Melitaea cinxia metapopulation. More recently, we have incorporated genetic and evolutionary components into our models, and this trend will be strengthened in the future.
Molecular Ecology Team
The Molecular Ecology Team emerged 4 years ago when the Department of Ecology and Systematics obtained a molecular laboratory. Initially, our research was focused on Melitaea cinxia, but over the past 3 years several other taxa have been studied as well, including other Melitaeini butterflies, dung beetles, old- growth forest specialist insect species, the flying squirrel and the least weasel. The research done in the Molecular Ecology Team is typically closely related to ongoing ecological projects in the MRG.
Forest Biodiversity Project
This project is funded by the Finnish Biodiversity Research Programme (FIBRE) and it has a 6-year 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, 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
16 moths.
Small Mammal Project
This project addresses the role of small mustelid predators (the least weasel and the stoat) in the maintenance of the regular multiannual population cycle of voles that is so characteristic of northern Fennoscandia. Theoretical studies have demonstrated that the predator-prey interaction may indeed drive the vole cycle, and that generalist predators may have a strong stabilizing effect on vole dynamics. Ongoing empirical work is focused on a large-scale experiment, in which captive- born least weasels are released on experimental islands in lakes to eliminate the numerical response in weasels' population dynamics. We conduct research on the breeding biology and behaviour of the least weasel. Another field study investigates the cyclic populations of the collared lemming in eastern Greenland.
Tree Canopy Insects Project
This is a new and still relatively small project focused on the spatial structure and dynamics of insect populations living in tree canopies. The field studies will be started in the summer 2000 on selected taxa living on the oak, which has a highly fragmented distribution in Finland and often occurs in small groups of trees or as single isolated trees.
TMR network Fragland
This is an EC-funded network in the Training and Mobility of Researchers Programme. The project has a 4-year duration, from 1998 until 2001. 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.
17 MRG personnel: Research interests
Mar Cabeza, Post graduate student
My PhD project aims to develop site-selection algorithms for the design of reserve networks. The idea is to combine the current site-selection algorithms that maximize the diversity of the reserves with an approach that will account for spatio-temporal dynamics (based on metapopulation models). The objective is to select those sites that ensure the persistence of the species given some constraints (e.g. a limited budget). The combination of the two approaches through a decision making process will allow us to weight the importance of the dynamics in the system and the importance of, say, the spatial heterogeneity and species representativeness. It remains to be seen whether there will appear common patterns in the selected sets by the two approaches. Until now, we have been dealing with single species (metapopulation) conservation problems. Currently, I am developing the multispecies dynamic approach and the decision making analysis. At the same time, I am collecting empirical data that will allow me to test the performance of the algorithms.
Olivier Gilg, Post graduate student
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 conclusions on the 70-yr-old puzzle of rodent dynamics, several hypotheses need to be tested combining appropriate empirical and theoretical approaches. For this purpose, the empirically-based models developed by Hanski and coworkers during the past ten years will be adapted and tested 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 has been initiated in 1998 in order to collect information needed to parameterize the model. Other topics regarding predator-prey interactions, such as prey selection, are also addressed in my PhD. Before joining the MRG, I worked for several years in a conservation agency. In my MSc thesis I developed a naturalness assessment method for old-growth and managed forests (University of Aix-Marseille-F).
18 Weidong Gu, Post doc
My study in the MRG involved statistical modelling of the distribution of the lichen Lobaria pulmonaria in boreal forests and dynamic modelling of the same species in a dynamic landscape (aspen and willow) using a patch occupancy model (IFM). Another project I was involved in was focused on the consequences of spatial and temporal isolation of habitat fragments on species occurrence in a dynamical landscape. Digitized historic maps of the boreal forest coverage in a landscape were incorporated in our modelling using a GIS (ArcView) based grid- cell transformation.
Tapio Gustafsson, Research Secretary
I am working as a research secretary to Professor Ilkka Hanski. One part of my work is to take care of the computing hardware and software used in the MRG. I produce illustrations for different purposes including our website. I help to co-ordinate our group activities and write reports etc. During the summer I have been teaching undergraduate students in the field cource of Subarctic Ecology in the Kilpisjärvi Biological Station.
Sari Haikola, Post graduate student
On the basis of numerous studies it can be concluded that inbreeding lowers general viability of an individual. The magnitude of inbreeding depression can be great in some species, and its consequences in natural populations may have been generally underestimated. 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 being conducted at the Tvärminne Zoological Station from the beginning of 1999. My main interests are in quantifying inbreeding depression in Glanville fritillary butterfly, Melitaea cinxia, and demonstrating any possible relationship between the magnitude of inbreeding depression and population`s past inbreeding history in this species.
19 Ilkka Hanski, Professor and director of the MRG
My research is aimed at developing testable models and theory in population biology and at testing such models. Currently the main focus is on metapopulation ecology, but research is also done on predator-prey theory applied to the dynamics of small mammals and their mustelid predators and on general issues concerning biodiversity in virgin boreal forests. The metapopulation research includes a range of modelling studies, from modelling the individual movement behaviour to questions about patterns in multispecies communities, as well as the supervision of several empirical projects. Given my responsibilities and other duties, the time available for personal research is limited, and the research tends to be done in collaboration with students and post docs.
Paavo Hellstedt, Post graduate student
My PhD research is focused on four aspects of stoat and weasel population biology. First, estimating the survival rate of captive-born least weasels in nature. We suggest that there are two main factors explaining variation in the survival rates, the age of the animal and time of year of release. Second, we have estimated the indirect effects of least weasel presence on Microtus vole behaviour and demography. Third, in Lapland, we have studied the causes of an apparent change of the microtine cycles and the dynamics, habitat and prey selection of stoats. We hypothesize that changes in mustelid densities are reflected in changes in microtine populations. Fourth, we attempt to estimate the population size of stoats and least weasels and the relatedness of individuals using molecular genetic markers.
Nathalie Jarosz, Post graduate student
My main research interests are population ecology and conservation biology. During the past two years, I have focused on using metapopulation modelling to understand the dispersal and colonisation strategies of marine invertabrates living in hydrothermal vent habitats, and in the English Channel. I have refined and improved a drift-flux model, which simulates gene flow in metapopulations to predict population genetic structure in space and time. In the MRG, I have started a short project on the butterfly Melitaea cinxia in order to model the distribution of allele frequencies
20 in response to interesting metapopulation parameters. If I could lengthen my stay, I would like to model a multiallelic system in order to achieve a more realistic model and to try to validate my results with molecular data. The main goal of this research is to explain the effects of fragmentation on species living in disturbed habitats and to anticipate and to predict their evolution.
Atte Komonen, Post graduate student
I started my PhD project in the spring 1997 as a part of the comprehensive project "Biodiversity in boreal forests". My personal research interest is the structure of communities and food webs in old-growth forest specialist insect species inhabiting bracket fungi. I have especially focused on the effects of forest fragmentation on fungal insect communities in small old-growth forest fragments. The main study fungal species are the old-growth forest specialist polypores Amylocystis lapponica and Fomitopsis rosea. Since September 1999, I have been working as UNV wildlife biologist in Choibalsan, Mongolia, dealing with the biodiversity issues in Mongolia’s eastern steppe. In the autumn 2001, I will return to finish my PhD in Helsinki.
Steve Matter, Post doc
My research interests lie in population and community ecology. Currently, I am examining the community-level patterns generated via metapopulation processes of individual species. Specifically I am trying to determine the degree to which metapopulation dynamics offer a unique explanation for the relationship between single species distribution and abundance and the species-area relationship.
Atte Moilanen, Researcher
I am mainly involved in computationally intensive studies due to my background in computer science. So far my main subject in the MRG has been metapopulation modeling and simulation - In 1998 I completed a PhD in ecology on the topic "Modeling metapopulation dynamics". A large part of this work was about parameter estimation methods for stochastic patch occupancy models. Currently I am starting work also with site selection
21 methods (collaboration with Mar Cabeza) and metapopulation genetics (collaboration with Ilkka Hanski). As a sideline, I am also interested in optimization methodology. I continue to work towards a Dr. Tech. degree in the Helsinki University of Technology, where I in 1998 completed a licentiate degree in applied mathematics on the topic "Optimization using evolutionary algorithms and local search".
Marko Nieminen, Researcher
My current research interests are primarily focused on studies on the Glanville fritillary butterfly (Melitaea cinxia) in Åland Islands, SW Finland. The two main research projects are: 1) To study the significance of and variability in the different causes of spatially correlated dynamics in M. cinxia metapopulations, and the spatial scales at which they operate. Two factors are probably driving spatially correlated dynamics: weather and changing landscape structure. Weather and changing landscape also operate indirectly via several other factors which in turn may have direct effects on the dynamics of the butterfly. These factors include host plant characteristics, parasitoids, inbreeding effects and habitat quality. 2) Running the bi-annual monitoring of all known habitat patches (ca 4200 at present) suitable for M. cinxia. This monitoring accumulates information on habitat characteristics and the presence of local populations every autumn, and on the numbers of M. cinxia larvae and parasitoids in the spring.
Saskya van Nouhuys, Post doc
I am concerned with 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 PhD (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 am working primarily on the large and small-scale population ecology of the parasitoids associated with the Glanville fritillary butterfly in Åland, Finland. I approach ecological and evolutionary questions of parasitoid dispersal, competition, hyperparasitism, searching behaviour and life history variation using experiments in the field and the laboratory and long-term observational field data, and by working in collaboration with a chemist and population geneticist in the MRG.
22 Bob O´Hara, TMR Post doc
I have come into the world of ecology and conservation from plant pathology, where conserving plant pathogens was the last thing we wanted to do (actually, that is not quite true - if we killed off all the plant pathogens, we would have been out of a job). I am working on applying Bayesian statistical methods to ecological data (in particular the Incidence Function Model, which should have a web site of its own). In order to avoid coming into contact with any real organisms, I spend much of my time hiding at the Rolf Nevanlinna Institute (go there and find out what they did to deserve me). On the rare occasions that I do appear in the department I spend my time dodging statistical questions, on topics as diverse as inbreeding in M. cinxia and density-dependent predation in voles. I am paid to do all this by the EU, through the Fragland project.
Otso Ovaskainen, Post doc
I completed my PhD on mathematics in the Technical University of Helsinki in 1998, and have worked as a post doctoral researcher in the MRG since June 1999. As a member of the modelling team, my research interests are directed to mathematical analysis of spatially structured metapopulation models. In 1999 I have studied a concept termed metapopulation capacity, characterizing the capacity of a habitat patch network to support a viable metapopulation from the viewpoint of deterministic metapopulation models. In the future, I plan to incorporate some ecologically relevant extensions to this concept, such as regional stochasticity and its interaction with spatially varying habitat quality, as well as metapopulation dynamics in dynamic landscapes. My other research plans include e.g. the relationship between deterministic and stochastic metapopulation models.
Jodie Painter, Researcher
My main research interest is in the application of molecular genetics to address questions of population ecology. For my PhD thesis, completed in 1997, I used molecular techniques to investigate the behavioural ecology of a cooperatively breeding honeyeater, thesis entitled "Colony structure and relatedness in the cooperatively breeding bell miner, Manorina melanophrys". I developed DNA microsatellite markers and
23 used this data in conjunction with behavioural data of nesting behaviour to investigate patterns of relatedness amongst cooperating individuals in this species. Within the Metapopulation Research Group, I am working as the senior researcher of the Molecular Ecology team, and I am responsible for the development and application of molecular techniques for the study of genetic diversity in species that inhabit boreal forests, particularly in boreal forest specialists. This will primarily be achieved through the development and use of DNA microsatellite markers for selected taxa. Other projects occuring within the Molecular Ecology team include the construction of phylogenies for melitaeine butterflies (N. Wahlberg) and the melitaeine-associated Cotesia wasps (M. Kankare), and investigation of the population genetics of various species, including Melitaea cinxia (I. Saccheri and K. Schöps), the two primary parasitiods of M. cinxia (M. Kankare) and the highly endangered beetle Pytho kolwensis, a boreal forest specialist (A. Komonen).
Tomas Roslin, Post doc
My main research interest is the empirical analysis of spatial population structures in insects using several complementary approaches. In my PhD thesis (completed in 1999), I focused on dung beetles in the genus Aphodius. My main objectives were twofold: 1) To compare spatial population structures among several closely related species co-occurring on a common resource, namely cattle dung, and 2) to relate the spatial population structures of individual species, and groups of ecologically similar species, to their abundance, distribution and dynamics at several spatial and temporal scales. In my post doc project, I will apply the same ideas to a new system: herbivorous insects in tree canopies. As a new ingredient, I will study how landscape structure affects the potential for local evolutionary adaptation.
Katrin Schöps, Post doc
During the past two summers my research aimed at establishing whether Melitaea cinxia females with different post-alighting preferences can discriminate between their host plant species prior to alighting. In laboratory and field experiments I have investigated whether pre-alighting and post-alighting preferences are correlated, and whether the butterflies learn from previous host plant encounters. Pre-alighting and post-
24 alighting preferences were strongly correlated. I also used DNA microsatellite markers to establish whether M. cinxia larvae that came from the same “nest” (a conspicuous web built by a group of larvae) were siblings. However, the microsatellite loci were not sufficiently polymorphic to answer this question. Currently I am collaborating with Karin Johst from the UFZ in Leipzig. We are modelling "Metapopulation persistence in a consumer-resource system with locally unstable dynamics". In the past, I studied the dispersal pattern and metapopulation dynamics of an endangered monophagous weevil that frequently causes local extinction of its host plant through overexploitation. (PhD thesis, Lincoln University, New Zealand).
Rosemary Setchfield, TMR Post doc
At present my interest is focused on the spatial processes influencing the dynamics of fragmented populations. My PhD research was concerned with population dynamics and spatial responses in plant-insect herbivore interactions. I found an overriding importance of root herbivory (by a beetle) for the short- and long-term dynamics of the biennial plant (a Composite), and root herbivore and egg parasitoid responses to spatial isolation of host plants on local (individual plants) and regional (patches) scales. I am currently employed as a post doc in the EC-funded TMR project Fragland. My contract in Helsinki terminated in April 1999, until which time I acted as Scientific Coordinator for the project. I continue my TMR contract in Leipzig where I am working on an individual-based, spatially-explicit model of patch emigration rate. The model explores the effects that spatial distribution and abundance of host plants can have on potential loss rates of host- specific butterflies from habitat patches. I plan to extend this line of research to model the effect of host plant preference on dispersal rate and consequent evolution.
Mika Siljander, Research assistant
My background is in development geography. As a member of the MRG my main task is to build up a geographical information system (GIS) of Melitaea cinxia metapopulation data. Metapopolation database is built in Access 97 and it will be linked to GIS system. At the present time the metapopulation database includes information on a network of more than 4000 small habitat patches in Åland Islands within an area of 50 by 70 km². These patches have been completely surveyed in the field.
25 Prospects for the year 2000 is to complete a GPS survey of the habitat patches and to convert the output to GIS system. Additionally, the entire Åland Islands will be remote sensed with an AISA instrument (the Airbone Imaging Spectrometer for Applications). The final aim is to make metadata of Melitaea cinxia metapopulation field data joined with GIS and remote sensed data.
Janne Sundell, Post graduate student
The main interest is the population dynamics of microtine rodents. The aim of the PhD project is to test the predator-prey hypothesis about the cyclic vole populations with a large-scale field experiment, in which vole-weasel dynamics on large islands in lakes are perturbed by adding captive-born weasels to cause a premature decline of vole populations. Subsequently the aim is to keep the vole density at a permanently low lewel by further additions of weasels. The experiment was started in 1997 and will continue in 2000. My other interests include the functional response and the prey choice of the least weasel. A captive breeding program of least weasels for the large-scale field experiment will also produce valuable information on various aspects of least weasels' reproduction biology for my PhD dissertation.
Anu Väisänen, Research Secretary
I have started in the MRG in the beginning of August 1999. I work as a research secretary and my work is mostly administrational. The main tasks are to help with the co- ordination of the largest projects and to manage the budget and the payment transactions. Daily co-ordination includes updating the web-pages and much of correspondence with the researches. I also participate in most group meetings and arrange practical matters especially for meetings that take place in Finland. Helping to prepare reports and proposals is also part of my work.
26 Niklas Wahlberg, Post graduate student
I have been working on a comparative study of butterflies in the tribe Melitaeini (Nymphalidae) and my PhD thesis is nearing its completion. My thesis will be consist of 5 articles plus a summary chapter. The subjects of the five articles are as follows: a molecular phylogeny of the tribe Melitaeini, the evolution of host plant use by melitaeines, a comparison of metapopulation structure and dispersal in five species of Finnish melitaeines, predicting the occurrence of an endangered species using knowledge of a well studied related species, and metapopulation dynamics in dynamic landscapes: a study of Euphydryas aurinia. The molecular phylogeny is based on the mitochondrial DNA sequences of 77 species of melitaeines (out of 250 spp.). I use the resulting phylogeny in my investigation of host plant use evolution, in which I conclude that host plant chemistry is the driving force behind host plant utilization in this group of insects. Melitaea cinxia is well known for its metapopulation in Finland. The four other species of melitaeines that I have studied also occur in discrete habitat patches. Two species persist through classical metapopulation dynamics, that is in a balance between extinctions and colonizations, and two species appear to have a patch network so dense that in practice all the patches are occupied almost all of the time.
Rongjiang Wang, Visitor
I am an assistant professor in the College of Life Sciences, Peking University. I visited the MRG from January to July in 1999. In this period, I focused on molecular ecology. The first project was on the DNA extraction from scats of the least weasel (Mustela nivalis nivalis). After improving the protocol, I successfully amplified mitochondrial D-loop fragment from scats, which was proved to be identical with that from the tissue of the least weasel by DNA sequencing. Further studies would involve processing of scat samples for identification of individuals. Using the DALP method, I analyzed the genetic relationships among the populations of Euphydryas and Melitaea collected in China. These two species of butterfly seemed to be good models for metapopulation research.
27 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 19 person. 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 by the rest of the Department of Ecology and Systematics.
28 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
We are in process of investigating vole-weasel dynamics with a large-scale field experiment. In this experiment we release weasels on large experimental islands in order to prevent the increase of vole populations and to keep the vole densities at a low level by further additions of weasels. In facilities provided by the Lammi Biological Station, we have started a captive breeding program of the least weasel. The facility include 17 outdoor enclosures, each 25 m² in size, which are used to habituate the weasels in outdoor life and to train them to hunt live prey before the release. Breeding of weasels is conducted in plexiglass cages in a greenhouse, where they are exposed to natural light conditions, but the facility gives also the possibility to control the photo period. In addition we have office space in main building of the station, and facilities for housing small mammals, mainly voles, for different purposes. The Lammi Biological Station has hired one half-time person to take care of the animals. Near the Lammi Biological Station we have radiotracked weasels, both captive-born and wild ones, and conducted a field experiment about the influence of the presence of weasels on population dynamics and demography of voles.
29 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, 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 ca 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 of typically tens of patches. The main reason for the aggregated distribution of habitat patches is that they are meadows which mainly occur within the cultural landscape on rocky outcrops, typically near small villages the patch-aggregates form well over one hundred habitat patch networks, of which many are occupied by the Glanville fritillary, and where the respective metapopulations have relatively independent dynamics. In 1999, ca 360 patches were occupied by the Glanville fritillary. The average size of the habitat patches is only 1200 m2, and the average 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 often to a large extent correlated spatially, but different parts of Åland typically have independent contradictory trends between any two years.
30 Kuhmo
In the past 100 years, modern forestry has dramatically changed the Finnish landscape. Today the remaining amount of old-growth forest 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 species is Kuhmo in eastern middle Finland. A further important feature there is the vicinity of a large extent of virgin forests in Russia, which maintains viable populations of taiga species and may serve as a source for isolated Finnish populations. 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 basis 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 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 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
31 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.
Forest fragmentation studies in central Finland
Effects of forest fragmentation on old-growth forest species have been studied in Häme, south-western Finland in 1998 and 1999. The study areas consist of 18 old- growth forest fragments, which vary in size from 2 to 250 ha. The taxa that have been studied include birds, lichens, polypores and insects (especially saproxylic beetles). Forest structure and quality were recorded by systematic line sampling, including variables such as living trees, age of the dominant tree layer, coarse woody debris, cut stumps, openness of the forest and proportion of swampy areas. Species inventories and forest structure inventories were made in 9 ha study plots if the old-growth forest fragment was greater than 9 ha.
Weasel-vole experiment on islands in lakes
The large-scale field experiment on the dynamics of microtine rodents and their main mammalian predator, the least weasel, is conducted on three experimental islands in lakes in southern and central Finland. The experimental islands, as well 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 ca 1 km² of primary vole habitat, that is meadows, old fields and clearcut areas with plenty of hey. The vole population dynamics are studied by live-trappings and biannual snap-trappings in both control and experimental areas. We also conduct avian predator and small game censuses. Experimental additions of least weasels have been started in all three regions. Some of the released weasels have been radiotracked in order to obtain information about their movements and survival.
Stoat dynamics in Kilpisjärvi
We have monitored stoat dynamics in the Kilpisjärvi area (69'' 10' N, 20'' 50' E), Finnish Lapland, where we have used the Kilpisjärvi Biological Station as a base. Most of the landscape is open tundra, but in low altitude valleys subarctic birch forest dominates. In the summer 1998 we started live-trapping and radio-tracking of small mustelids and we continued these studies in summer 1999. In addition we have counted snow tracks along 10 km lines in November and January. The snow track lines are located in two different habitats, along a more productive lakeshore line and along a less productive birch forest slope. Home range size and
32 movements of stoats depend on season and food resources. Females and males live in different habitats: males commonly hunt in the forest while females prefer open habitats. Females' home ranges are smaller and they move less while hunting than males. Behavioural differences between the least weasel and the stoat, and changes in their relative densities might have significant consequence on vole population oscillations. This research is done in cooperation with the Finnish Forest Research Institute (Heikki Henttonen).
Stoat habitat in the open tundra in the Kilpisjärvi area.
33 Synopsis of the year 1999
Budget
Funding Source FIM
Academy of Finland Centre-of-excellence funding to the DPB 219 196 Metapopulation biology 1 870 685 Small mammal population dynamics 659 468 Biodiversity in boreal forests 464 540 Post doc salaries 203 412
Ministry of Agriculture and Forestry Biodiversity in boreal forests 200 000
Ministry of Education Centre-of-excellence funding to the DPB 935 258
European Comission Survival of species in fragmented landscapes 453 449
University of Helsinki Butterfly breeding facility 63 813
Centre for International Mobility Scholarships 24 000
TOTAL 5 093 822
Ministry of Environment Biodiversity in boreal forests * 1 000 000
* managed by the Research Centre of the Friendship Park in Kuhmo
34 Publications
Dieckmann U., O'Hara R.B. and Weisser W. 1999. The evolutionary ecology of dispersal. Trends Ecol. Evol. 14, 88-90.
Gu, W.D., Kuusinen, M., Konttinen, T. and Hanski, I. 1999. Spatial analyses of the lichen Lobaria pulmonaria in boreal forests. Ecography (submitted)
Hanski, I. 1999. Metapopulation Ecology. Oxford University Press, Oxford.
Hanski, I. 1999. Habitat connectivity, habitat continuity, and metapopulations in dynamic landscapes. Oikos 87, 209-219.
Komonen, A., Penttilä, R., Lindgren, M. and Hanski, I. 1999. Forest fragmentation truncates a food chain based on an old-growth forest bracket fungus. Oikos (in press)
Matter, S.F. 1999. Population density and area: the role of within- and between- generation processes over time. Ecological Modelling 118: 261-275.
Moilanen, A. 1999. Patch occupancy models of metapopulation dynamics: efficient parameter estimation using implicit statistical inference. Ecology 80, 1031-1043.
Moilanen, A. 1999. Searching for most parsimonious trees with simulated evolutionary optimization. Cladistics 15, 39-50.
Nieminen, M., Rita, H. and Uuvana, P. 1999. Body size and migration rate in moths. Ecography 22, 697-707. van Nouhuys, S. & S. Via. 1999. Natural selection and genetic differentiation of behaviour between parasitoids from wild and cultivated habitats. Heredity 83, 127- 137. van Nouhuys, S. & I. Hanski 1999. Host diet affects extinctions and colonizations in a parasitoid metapopulation. Journal of Animal Ecology 68, 1248-1258. van Nouhuys, S. & I. Hanski. 1999. Apparent competition between parasitoids mediated by a shared hyperparasitoid. Ecology Letters (in press)
35 Schöps, K., Wratten, S.D. and Emberson, R.M. 1999. Life cycle and behaviour of the large endemic weevil, Hadramphus spinipennis and implications for conservation . New Zealand Journal of Zoology 26, 55-66.
Turner, A.S., O’Hara, R.B., Rezanoor, H.N., Nutall, M., Smith, J.N. and Nicholson, P. 1999. Visual disease and PCR assessment of stem base diseases in winter wheat. Plant Pathology 48, 742-748.
Wahlberg, N. 1999: Kirjoverkkoperhosen (Euphydryas maturna) elinympäristö Suomessa [The habitat of Euphydryas maturna in Finland]. Baptria 24, 173-177.
Zhang, D.-Y., Lei, G.-C. and Hanski, I. 1999. Metapopulation dynamics: theory and applications (in Chinese). Chinese Biodiversity 7, 81-90.
Theses
Tomas Roslin, PhD: Spatial Ecology of Dung Beetles
During the past few decades, there has been a surge of interest in the influence of space on the structure and dynamics of populations and ecological communities. So far, the development of this new field of “spatial ecology” has been hampered by scarcity of empirical data on real ecological systems. In my PhD thesis, I attempted to add a small piece of that missing information. I used several complementary approaches to study both spatial population structures and consequent dynamics in a group of species not studied in the context previously, dung beetles in the genus Aphodius. I focused on some ten closely related species, which all co-occur on the same patchily distributed resource – cattle dung on pastures. Related species utilising similar resources are often assumed to show similar spatial population structures and dynamics. My thesis reports considerable ecological variation within a set of closely related dung beetle species. Interspecific differences in spatial population structures are created by variation in ecological specialisation and habitat selection, in migration rates and movement patterns, and in the distribution of local population sizes. These differences cause dissimilar spatial dynamics, as was evident from variation in species’ sensitivity to contemporary landscape composition, and from differences in their responses to habitat loss over time. During the 20th century, dissimilar dynamics among Aphodius species have resulted in considerable changes in the Finnish dung beetle assemblages, with at least four species becoming increasingly rare and one species expanding its distribution. At the community level, interspecific differences in
36 spatial population structures make the local community composition a function of the structure of the surrounding landscape.
Atte Komonen, PhL: Biology of insect populations and communities inhabiting old- growth forest polyporous fungi
In my thesis, I studied the insect community in two old-growth forest specialist bracket fungi, Amylocystis lapponica and Fomitopsis rosea. I focused on the effects of forest fragmentation on these fungal insect communities in small old- growth forest fragments. The study was carried out in boreal spruce-dominated old-growth forests in southern and eastern Finland, which have different proportions of old-growth forest remaining. Old-growth forest areas in southern and eastern Finland were compared to assess the effects of large-scale forest fragmentation. In addition, samples of F. rosea from large non-isolated control areas were compared with samples from forest fragments in two isolation time classes, 2-7 years and 12-32 years since isolation. Amylocystis lapponica and F. rosea each had an insect community of more than 50 species. The occurrence of several nationally or globally rare species underscores the importance of specific insect microhabitats, such as the old-growth fungi A. lapponica and F. rosea, for the persistence of specialised insects in old- growth forests. The community structure was the same in the highly-fragmented and in the non-fragmented study areas, probably because fragmentation has occurred relatively recently and the fragments studied are tens of ha in size on average. In the very small fragments, fragmentation was shown to truncate a food chain based on F. rosea. Species at higher trophic levels were especially vulnerable to extinction, and the specialist parasitoid of the primary fungivore inhabiting F. rosea was completely missing from the fragments isolated for the longest period of time.
Eva Kallio, MSc: Behavior and survival of captive-reared least weasels in nature
For experimental purposes captive-reared least weasels were released into nature. During the summer 1997 seven radio-collared weasels (4 males and 3 females) were released in the Lammi region. Home ranges, movements and habitat selection of the weasels were observed. Weasels were active about 20% of time. Mean movement speed was 110 m/h for females and 290 m/h for males. Extrapolating from these values, females moved about 540 m and males 1200 m per day. An important reason for extended movements may be problems in locating and killing prey. Mean home range size (100% MCP) was 1.3 ha for females and 10 ha for males, which correspond to values in the literature. Weasels preferred deciduous forests in their home range. The daily survival rate (DSR) was 97.7 %. Comparing
37 to results on weasels that were released in other times of the year, the survival rate was higher in weasels released during the summer.
Tiia Kalske, MSc: Estimating the indirect effects of least weasel presence on field vole behaviour and demography in a field experiment
In the summer 1998, I studied the indirect effects of the least weasel (Mustela nivalis nivalis) on field voles (Microtus agrestis) in a semi-natural field experiment. I primarily considered the female behaviour, attainment of maturity, breeding success, weight, movement behaviour and home range size. The mere presence of a predator did not induce any substantial behavioural or demographic changes in the field voles nor in their populations.
Vole trapping area in Punkaharju.
38 External visits
Ilkka Hanski, Atte Komonen and Juha Siitonen, visited the Fenglin Forest Reserve in NE China for 1 week in July 1999, to explore the possibility of initiating field research on boreal forest biodiversity in the year 2000.
Paavo Hellstedt, visited Maano Aunapuu´s research area in Joatka, Alta, Norway (Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Science, Joatka Group), in July 1999.
Marko Nieminen, visited Josef Settele (UFZ - Centre for Environmental Research Leipzig-Halle Ltd., Department of Conservation Biology and Natural Resources, Leipzig) to check out local M. cinxia habitats on the area of Bamberg.
Saskya van Nouhuys, visiting researcher at Cornell University in Ithaca NY.
Bob O´Hara, visited Christian Wissel´s group in Leipzig for 1 week in June to discuss Bayesian modelling.
Tomas Roslin, visited the “Ecology of Canopy Insects” Project of Dr Yves Basset, Smithsonian Tropical Research Institute, Republic of Panama, 25th October – 15th November.
Rosemary Setchfield, visited the TMR labs in Montpellier, Cordoba, Leiden, Louvain and Leeds in January 1999.
Rosemary Setchfield, visited the Åland Islands to do research on M. cinxia dispersal in June 1999 (after finishing the Helsinki contract on 30th April).
Niklas Wahlberg, visited Chris Thomas´ group in Leeds for one month in October to learn about mark-recapture data analysis.
Seminars, lectures and talks
Ilkka Hanski gave lectures on metapopulation biology in the University of Connecticut (USA) in March and in the University of Miami (USA) in September 1999.
Ilkka Hanski gave an invited lecture entitled “New developments in ecology” in
39 the inaugural ceremony of a new biology building at the University of Umeå, Sweden, in November 1999.
Ilkka Hanski gave an invited lecture in a meeting on Population Viability Analysis in San Diego (USA) in March 1999.
Ilkka Hanski made presentations in a workshop on “Metapopulation Biology” in Tvärminne in April 1999, in another workshop on “Evolution of Dispersal” in Roscoff, France, in April 1999, and in the conference on “Habitat Loss” in Helsinki in September 1999.
Ilkka Hanski talked in several domestic meetings on forest biodiversity conservation throughout the year 1999.
Atte Moilanen, "Single species dynamic site selection" in the conference on “Habitat Loss” in Helsinki in September 1999.
Marko Nieminen, “Experimental confirmation of inbreeding depression increasing extinction risk in Melitaea cinxia populations” in meeting Survival and evolution of species in fragmented landscapes, Cordoba (Spain), February 1999.
Marko Nieminen, “Perinnebiotooppien perhoset Saaristomeren kansallispuiston alueella [Lepidoptera of cultural biotopes within the Archipelago Sea National Park]” in meeting of Helsingin Hyönteistieteellinen Yhdistys, Helsinki, March 1999.
Marko Nieminen, “Inbreeding depression increases extinction risk in Melitaea cinxia populations (Lepidoptera, Nymphalidae)" in 20th Finnish Entomological Days, Jomala (Åland), June 1999.
Marko Nieminen, “Inbreeding depression increases extinction risk of Melitaea cinxia populations” in Butterfly Conservation´s 3rd International Symposium, Oxford (UK), September 1999.
Marko Nieminen, “Methods of long-term large-scale metapopulation survey of Melitaea cinxia” in Butterfly Conservation´s 3rd International Symposium, Oxford (UK), September 1999.
Marko Nieminen, “Inbreeding depression increases extinction risk in populations of the butterfly Melitaea cinxia” in meeting Habitat loss: Ecological, evolutionary and genetic consequences, Helsinki, September 1999.
40 Saskya van Nouhuys, “Population dynamics of a parasitoid wasp: from individual to metapopulation”. Presented to the Department of Biology, Colorado State University, Ft. Collins Colorado (October 1999).
Saskya van Nouhuys, “Population dynamics of a parasitoid wasp: from individual to metapopulation”. Presented at the XII International Entomophagous Insect workshop in Asilimar, CA (September 1999).
Saskya van Nouhuys, “Hotet mot arter med hökblomsternätfjärilen Melitaea cinxia som exempel” (in English, translated to Swedish). Presented as part of a seminar on meadow ecology at The Landscape School in Åland, Finland (June 1999).
Saskya van Nouhuys, “Metapopulation dynamics of a parasitoid wasp”. Presented in the weekly Lunch Bunch seminar series of the Department of Ecology and Evolutionary Biology, Cornell University (February 1999).
Saskya van Nouhuys, “Host diet affects extinctions and colonizations in a parasitoid metapopulation”. Presented at the 23rd annual Ecology and Evolutionary Biology Symposium, Cornell University (January 1999).
Bob O´Hara, “Fitting Models of Metapopulations to Data”. Scientific Meeting of the European TMR (program of the European Union for the Transport and Mobility of Researches) network 'Survival of Species in Fragmented Landscapes', Cordoba, 19th - 21st February 1999.
Bob O´Hara, “Fitting Metapopulations Models to Data”. ESF Metapopulation Dynamics Workshop, Tvärminne Zoological Station, 15-18 April, 1999.
Bob O´Hara, Seminar on Metapopulation modelling in Leipzig (June 1999).
Bob O´Hara, Seminar at the Game and Fisheries Research Institute, Helsinki, on Bayesian modelling of metapopulations (December 1999).
Katrin Schöps, “Can the Glanville frittillary spot the difference between its two host plants? - Alighting preference and adaptive learning of ovipositing Melitaea cinxia butterflies”. Scientific Meeting of the European TMR (program of the European Union for the Transport and Mobility of Researches) network ‘Survival of Species in Fragmented Landscapes’, Cordoba, 19th – 21st February 1999.
41 Katrin Schöps, “Metapopulation dynamics of an endangered weevil and its host plant on the Chatham Islands (New Zeeland) - a conservation approach”. Department of Agroecology, University of Goettingen, 3rd March 1999.
Katrin Schöps, “Metapopulation dynamics of an endangered weevil and its host plant on the Chatham Islands (New Zeeland)”. UmweltForschungsZentrum Leipzig-Halle, 25th August 1999.
Katrin Schöps, “Effect of deforestation on the spatial dynamics of an endangered weevil species”. Conference on Habitat Loss: Ecological, Evolutionary and Genetic Consequences, Helsinki, Finland, 7th – 12th September 1999.
Niklas Wahlberg, “Verkkoperhosten molekyylifylogenia [A molecular phylogeny of checkerspot butterflies]” Societas Entomologica Helsingforsiensis meeting, Helsinki, February 1999.
Niklas Wahlberg, “A molecular phylogeny of the tribe Melitaeini (Lepidoptera: Nymphalidae)” Scientific Meeting of the European TMR (program of the European Union for the Transport and Mobility of Researches) network “Survival of Species in Fragmented Landscapes”, Cordoba, 19th - 21st February 1999.
Courses
Tapio Gustafsson, teacher at the field course on Subarctic Ecology in the Kilpisjärvi Biological Station 29th June – 7th July 1999.
Atte Moilanen, leading teacher in UIMIR (Universitat International de Menorca Illa del Rei) international summer school on “Habitat loss, fragmentation and metapopulations” 13th – 17th September.
Honors and awards
Ilkka Hanski was awarded the International Ecology Institute (ECI) 1999 Prize in Terrestrial Ecology.
Ilkka Hanski was awarded the President's Gold Medal of the British Ecological Society in the Annual Meeting in Leeds in December 1999.
42 Council Memberships
Ilkka Hanski has served in the Scientific Advisory Board of the National Center for Ecological Analysis and Synthesis (NCEAS) in Santa Barbara (USA).
Marko Nieminen has served as a board member and conservation committee member in the Finnish Lepidopterological Society and as an editor of supplementary volumes.
Tomas Roslin has served as a Member of the Board of the Societas Entomologica Helsingforsiensis, Helsinki, Finland.
Tomas Roslin has served as a Member of the Organizing Committee for the 20th Finnish Days of Entomology organized by the Societas Entomologica Helsingforsiensis, Helsinki, Finland.
Meetings organized by the MRG
Annual Meeting of the MRG, at the Tvärminne Zoological Station in January.
TMR workshop on “Metapopulation Modelling”, at the Tvärminne Zoological Station in January 1999.
TMR Annual Meeting in Cordoba, Spain, in February 1999.
Workshop on “Metapopulation Biology”, organized by the European Science Foundation program on Theoretical Biology, Tvärminne Zoological Station in April 1999.
International Congress on “Habitat Loss”, organized by the Spatial Ecology Program at the Department of Ecology and Systematics in Helsinki in September 1999.
Steering Committee meeting of the TMR Fragland network in Leiden in November 1999.
43 Visitors to the MRG
Michael Antolin, Habitat loss conference and laboratory work, August-September 1999.
Maano Aunapuu, visited Paavo Hellstedt´s research area at the Lammi Biological station in August 1999.
Karin Frank, Habitat loss conference and collaborative research, September 1999.
Sandrine Petit, collaborative research, January-February 1999.
Kazunori Sato, to discuss his work “Analysis of spatially explicit metapopulation models by pair approximation” with members in the MRG and to take part to the Habitat loss conference, September 1999.
Narayan Behera, collaborative research, November 1999.
Typical Melitaea cinxia habitat patch in the Åland Islands.
44 Prospects for the year 2000
From the beginning of the year 2000 the Metapopulation Research Group has the status and the funding of one of the centres-of-excellence in research that were chosen by the Academy of Finland at the end of 1998. The funding period covers 6 years, with a mid-term evaluation after the first 3 years. Some improvement in the level of funding will occur, though the change will not be dramatic. More importantly, our new status is a big challenge for us, an opportunity to demonstrate that we can live up to the promises of the past few years. No great changes are expected to occur in the direction of our research in 2000, and the turnover amongst the students and post docs will be moderate. Research will be intensified on several fronts, including all the three teams, the Melitaea cinxia Team, the Metapopulation Modelling Team and the Molecular Ecology Team. We now have funding for the Boreal Forest Biodiversity project for the next 3 years, including a planned extension of field work to NE China.
Old-growth forest in Kuhmo area.
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