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Impact of Geographical and Environmental Structures on Habitat Choice, Metapopulation Dynamics and Genetic Structure for Hazel Grouse (Bonasa Bonasia)

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Impact of Geographical and Environmental Structures on Habitat Choice, Metapopulation Dynamics and Genetic Structure for Hazel Grouse (Bonasa Bonasia) Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology 314 Impact of Geographical and Environmental Structures on Habitat Choice, Metapopulation Dynamics and Genetic Structure for Hazel Grouse (Bonasa bonasia) JONAS SAHLSTEN ACTA UNIVERSITATIS UPSALIENSIS ISSN 1651-6214 UPPSALA ISBN 978-91-554-6910-8 2007 urn:nbn:se:uu:diva-7911 !" # $ %&&$ '()&& * " * * +" ", !" - ", . " #, %&&$, / * 0 " . 1 " 2 0 . * 1 3 0 4 5, 6 , ('7, (8 , , /.9 $8: ':;;7:< '&:8, / " - = " * " 3 4 5 - * " * 49>65, !" * 9>6 " " 3 3 ** " " -" " , ?" * " * -"" * " - ** " * , !" : - 3 " * " , / - * " 3 * - 3 - " , / " " 3 * * , 1 - " " " ** " " , !" * " * " , / " " / * - * * ** , @ * " " : * " 3 - " * * , " " 3 " " 3 - , 0 * - - " , !" * * -" " * " . - " ": " , 9 - * " " ** * - * " " 3 , ! A + " + : 0 9" " 3 " # $ $ # % &' # # $()*+,- # B # . " %&&$ /..9 '<;':<%'7 /.9 $8: ':;;7:< '&:8 ) ))) :$ '' 4" )CC ,=,C D E ) ))) :$ ''5 If your heart is restless and you can't go on When you're tired and weary, but you can't go on Well a distant dream is a callin' you Then there's just one thing that you can do You gotta follow that dream wherever that dream may lead you -Bruce Springsteen For you! Rebecca, André & Jennie List of papers This thesis is based on the following papers, which are referred to by their roman numerals: I Sahlsten J. Predicting suitable habitats for Hazel Grouse (Bonasa bonasia) in a boreal region using niche factor analysis: A case study in south-central Sweden. (Submit- ted manuscript). II Sahlsten J., Höglund J. and Rapaport E. Landscape shape and land cover structure as determinants of pre- ferred areas by Hazel Grouse (Bonasa bonasia). (Manu- script). III Sahlsten J., Wickström F. and Höglund J. Hazel Grouse population dynamics in a fragmented landscape: A metapopulation approach. (Manuscript). IV Sahlsten J., Thörngren H. and Höglund J. Inference of Hazel Grouse population structure using multilocus data: A landscape genetic approach. (Manuscript). Cover photo by: Danielle Occhiato© Contents Introduction.....................................................................................................8 Methods ........................................................................................................11 The species ...............................................................................................11 Study area.................................................................................................12 Fieldwork .................................................................................................13 GIS and ENFA .........................................................................................14 Incidence Function Model........................................................................17 Landscape genetics...................................................................................20 Results and discussion ..................................................................................22 Census ......................................................................................................22 Ecological Niche Factor Analysis ............................................................22 Patch Structure .........................................................................................23 Incidence Function Model........................................................................25 Landscape Genetics..................................................................................27 Sammanfattning på svenska..........................................................................31 Acknowledgements.......................................................................................33 References.....................................................................................................35 Abbreviations ENFA Ecological Niche Factor Analysis HSM Habitat Suitability Map IFM Incidence Function Model GIS Geographic Information System EGV Ecogeographical Variable Introduction At present degradation and fragmentation of suitable habitats is one of the main reasons to why species decline and goes extinct. Therefore, it is a ma- jor concern to find and develop methods and models to make estimations and predictions of the dynamics driven by the landscape species face. In conservation or management strategies it is fundamental to identify suitable habitats and to determine geographic and geometric distribution of these areas (Wiens 1989, Keitt et al. 1997). In the last decades GIS (geographic information system) and remote sensing has become more readily available and studies of very large or remote areas has been simplified. Ecological niche factor analysis (ENFA) is a recently developed method to find suitable habitats at large scales and to compute habitat suitability maps (HSM) (Hir- zel et al. 2002a,b., Hirzel and Arlettaz 2003). This multivariate method, based on Hutchinson’s concept of ecological niche (Hutchinson 1957), was used to determine distribution of areas suitable for hazel grouse (Bonasa bonasia) in Uppland, south-central Sweden. The ENFA approach revealed that suitable areas in the studied region have a patchy distribution and it ind- cates that good habitat is available for hazel grouse in this region. Although the size and inner structure or content of patches is important, the geometric shape of patches may be equally important to determine the potential incidence of a species in a particular patch (Hargis et al. 1998; Hel- zer and Jelinski 1999). Size of a patch is often considered as linearly corre- lated with population size or species diversity (Martin and McComb 2003). The shape of a patch in terms of the perimeter-area ratio may, however, be more important when considering the suitability of patches (Collinge and Palmer 2002). Hence, different GIS applications and analyses were used in order to determine features of suitable areas, in terms of patch shape and land cover. At the studied resolution and extent the results indicate that hazel grouse is tied to coniferous forest and that they avoid open space. The pre- ferred composition and structure of land cover seem, however, to differ be- tween scales. Analyses of geometric measures indicate that size and espe- cially shape is important factors in the context of incidence of hazel grouse. This implies that consideration needs to be taken at more than one level of geographical scale in planning and management of hazel grouse. 8 If suitable areas are found to have a patchy distribution the species popula- tion dynamics may be assumed to fit a metapopulation (Hanski and Gilpin 1997). In a metapopulation modelling approach, the assumptions is made that the assembly of sub-populations have reached a steady-state in terms of colonization and extinction events (Hanski and Gilpin 1997). A stochastic, spatially realistic, occupancy model based on a first order linear Markov chain modelling describing the probability of occupancy for each single habitat patch (Hanski 1994, Hanski and Gilpin 1997) was used to simulate population dynamics of hazel grouse under different area measurement sce- narios. This model is denoted the incidence function model (IFM) and one basic assumption in the IFM is that the size of a sub-population is correlated to the size of the patch and extinction probability is correlated to the size of the population (Kindvall and Ahlén 1992, Hanski et al. 1996). However, the area alone could be a deceptive measures due to that some parts of the area having limited suitability due to edge effects. The relationship between pe- rimeter and area will determine the amount of impact on a patch. In order to analyze the impact of edges on occupancy levels and capacity, three differ- ent edge-zones were implemented into the incidence function model and pair -wise compared to a patch network where edges were not included (hereafter called the basic area). The results indicate that a landscape with high perime- ter length (i.e. high amount of edges) seems to be more sensitive to changes. Although number of patches was significantly lower when edges were con- sidered, no evidences were found for decreasing proportion occupied patches. In addition to resources within patches, a recommended strategy to favour hazel grouse in this region should be to preserve Euclidian shaped (Mandlebrot 1983) patches with a homogenous interior. Dispersal opportuni- ties should be considered by proper configuration of patches and land use planning should be at a scale that incorporates more than one or a few sub- populations. To understand the dynamics at a local scale it is also important to under- stand the pattern and processes of gene flow at a large scale (Manél et al. 2003). Spatial heterogeneity affects, among other things, dispersal and con- sequently gene flow (Holderegger et al. 2006). In conservation and man- agement of species, it is important to define groups of individuals as conser- vation or management units (Bonin et al. 2007). However, most previous methods used require
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