This thesis focuses on mechanisms and processes underlying spatial patterns of resistance and virulence and on local adaptations in plant–parasite interactions. The model system used comprises the plant host Salix triandra, the pathogenic rust fungus Melampsora amygdalinae, the leaf beetle Gonioctena linnaeana, and the galler Pontania triandrae. In this work, I (1) emphasize the most important factors determining the outcome of a plant–pathogen interaction, and the types of systems in which local adaptations can be expected, (2) examine the resistance structures of different populations of S. triandra, and whether the leaf beetle G. linnaeana responds to the local conditions of the populations of S. triandra in Sweden, and (3) address whether the distribution of parasites on S. triandra can be explained by the plant content of secondary metabolites. A review of several studies of the subject leads to the conclusion that adaptation of pathogens to their local hosts is more likely to be found in systems in which the pathogen is host-specific, non-systemic, and has a larger dispersal range and evolutionary potential than its host does. Furthermore, the scale of the study must be adjusted to that of the pathogen’s local population distribution. In addition, the temporary nature of host–pathogen interactions influences the importance of sample size, and too-small sample sizes can lower the chance of finding local adaptations, even though they may have evolved in a given system. The results of an inoculation experiment using material from physically isolated natural populations of S. triandra and M. amygdalinae confirm the importance of previous conclusions. Spatial variation in the resistance structure of S. triandra also has effects on the insect herbivore G. linnaeana, which has responded by adapting to the local hosts. However, local differences in secondary chemistry affect different parasites in different ways, and while P. triandrae is attracted by high levels of phenolic compounds, including tannins, M. amygdalinae and G. linnaeana are more rarely found on plant individuals with high concentrations of tannins. In addition, brood deposition by adult females of G. linnaeana and the performance of larvae are positively affected by luteolin-7-glucoside and an additional unidentified flavonoid, whereas they are negatively affected by the presence of (+)-catechin and high levels of tannins. Our results also show that plants traits that provide resistance to one type of parasite do not necessarily provide resistance to others. This indicates that different natural enemies potentially assert divergent selection pressure on S. triandra phenotypes which can be important for maintaining phenotypic variation in plant species.

<p>Forest canopies are a critical component of forest ecosystems as they influence many important functions. Specifically, the structure of forest canopies is a driver of the magnitude and rate of these functions. Therefore, being able to accurately measure canopy structure is crucial to ensure ecological models and forest management plans are as robust and efficient as possible. However, canopies are complex and dynamic entities and thus their structure can be challenging to accurately measure. Here we study the feasibility of using lidar to measure forest canopy structure across large spatial extents by investigating the compatibility of aerial and terrestrial lidar systems. Building on known structure-function relationships measured with terrestrial lidar, we establish grounds for scaling these relationships to the aerial scale. This would enable accurate measures of canopy structural complexity to be acquired at landscape and regional scales without the time and labor requirements of terrestrial data collection. Our results illustrate the potential for measures of canopy height, vegetation area, horizontal cover, and canopy roughness to be upscaled. Furthermore, we highlight the benefit of utilizing multivariate measures of canopy structure, and the capacity of lidar to identify forest structural types. Moving forward, lidar is a tool to be utilized in tandem with other technologies to best understand the spatial and temporal dynamics of forests and the influence of physical ecosystem structure. </p>

Commercial pine plantations made up of exotic tree species are increasingly recognised as habitats that can contribute significantly to the conservation of indigenous biodiversity in New Zealand. Encouraging this biodiversity by employing sympathetic forestry management techniques not only offers benefits for indigenous flora and fauna but can also be economically advantageous for the forestry industry. The New Zealand falcon (Falco novaeseelandiae) or Karearea, is a threatened species, endemic to the islands of New Zealand, that has recently been discovered breeding in pine plantations. This research determines the ecological requirements of New Zealand falcons in this habitat, enabling recommendations for sympathetic forestry management to be made. Plantation forests that create a mosaic of pine stand ages across a plantation, offer suitable habitat for breeding New Zealand falcons by providing abundant nest sites, promoting high abundances of avian prey and creating favourable conditions for hunting. The diet of falcons within pine forests consisted primarily of birds, of which the majority were exotic passerines. Prey abundances were highest along pine stand edges. Both sexes preferentially hunted along pine stand edges between stands less than four years old and stands more than 20 years old. Pairs also preferentially nested along these borders, particularly within and along the edges of pine stands less than two years old. Within pine stands, nest sites were always located on the ground. Introduced predators and some forestry operations negatively affected breeding success. Nevertheless, productivity was higher than recorded for other habitats and female falcons were recorded successfully breeding in their first year for the first time. High prey densities and availabilities are suggested as the primary explanation for this. The extent of juvenile dispersal strongly suggests that pine plantations supplement populations in surrounding areas where falcons are in decline. This research demonstrates that changes to the existing forestry operational practices can influence the success of the breeding population. This research establishes that if commercial pine plantations are suitably managed, they can support extremely high falcon densities. Plantation forests therefore have a significant role to play in the future conservation of this species.

The present study is part of the Kaupapa Kereru Programme. The main aim of the programme is to increase the numbers and range of kereru (Hemiphaga novaeseelandiae) on Banks Peninsula. Home ranges, movements, diet and habitat use of 15 kereru captured in Hinewai Reserve, Banks Peninsula, were investigated from February 2005 to February 2006. Hinewai Reserve is the largest tract of regenerating native forest in a highly modified urban-rural landscape. Phenology of 11 plant species predicted to be key kereru foods, was studied to determine the pattern of food availability in Hinewai Reserve. Twelve radio-tagged kereru resided in the Hinewai Reserve study site (Otanerito Valley and Sleepy Bay) and three resided in Akaroa. Ripe fruit was available from January to August; the height of the fruiting season was in autumn. The bulk of new leaf growth occurred in spring and early summer although new leaves were available on broom and tree lucerne year round. Peak flowering occurred in spring. Kereru in Akaroa ate a total of 21 plant species; six of these species were native and 15 introduced. Kereru in the Hinewai Reserve study site ate a total of 26 plant species; 20 of these species were native and six introduced. Fruit was preferred when readily available. Native fruit appeared to be preferred over fruit of introduced species in Akaroa, where both types were available. New foliage of introduced legumes and deciduous species appeared to be preferred over new foliage of native species at both sites during winter and spring. These species were important food sources prior to the breeding season and may be selected specifically for their nitrogen and protein content. Food is currently not a limiting factor for kereru survival or reproductive success. Considerable variation in the use and preference of vegetation types of individual kereru made it difficult to identify trends in habitat selection. Use and preference for many vegetation types was seasonal; this was certainly because of the availability of food species included in or close to these vegetation types. Overall, native vegetation communities were used more than communities dominated by introduced species and forest communities were used more than non-forest communities. Kanuka (Kunzea ericoides) was used most often for non-feeding activities and 67% of observed nests were built in kanuka. Annual home ranges and core areas in the Hinewai Reserve study site (mean of 15.9 and 2 ha respectively) were significantly larger than those found in Lyttelton Harbour, Banks Peninsula in previous research (mean of 8 and 0.08 ha respectively). Home ranges were larger when fruit was eaten, than when no fruit was eaten indicating that kereru are more sedentary when feeding on foliage. Kereru from the Hinewai Reserve study site made no excursions >5 km and no daily movements >2 km. Kereru from Akaroa and Sleepy Bay travelled into Otanerito Valley to feed on horopito in autumn, indicating that there may have been a lack of fruit in their local areas during autumn. No kereru in Otanerito Valley travelled outside of the valley. The distribution of high quality food sources is likely to have caused the observed differences in home range and core area size between localities. Kereru in Lyttelton Harbour may have been restricted to small patches of high quality resources in a study area consisting largely of unsuitable habitat. In Hinewai Reserve, high quality resources were spread over larger areas and were more uniformly distributed. The density of kereru was unknown at both study sites, and this confounded assessment of habitat quality. However, it is likely that the Hinewai Reserve study site would support a higher number of kereru. The main factor limiting population growth in the present study was failure of nests at the egg and chick stage. The fledge rate was 17%. Two of fifteen adult kereru died. Control of predators should be the first aspect of management that is focused on, and will almost certainly increase reproductive success of kereru and loss of breeding adults. As the population of kereru on Banks Peninsula increases due to predator control in existing kereru habitat, food may become a limiting factor. Habitat can be improved for kereru by planting a diverse range of plant species that provide food year-round. Native fruiting species are greatly recommended for habitat enhancement and should be selected so that fruit is available for as much of the year as possible. Native and introduced legumes should also be made available as foods for winter and spring. As most land on Banks Peninsula is privately owned, co-operation and enthusiasm of the community is critical for successful management. Information and support needs to be given to landowners wishing to enhance their properties for kereru.

<p>Pollination is one of the most important factors determining the reproductive success of plants. This thesis examines processes associated to varying pollination, with focus on plant responses. The first aim was to examine the possibility and constraints for short-term evolution of flower size in <i>Raphanus raphanistrum</i>. The results showed that there exists a possibility for pollinator-mediated short-term evolution of flower size in the study species. Flower size was strongly correlated to plant size. Since flower size cannot evolve separately from plant size, this correlation may constitute a constraint to the evolution of flower size. The second aim was to determine how varying pollen load affects later flowering, reproduction and growth of maternal plants. High pollen load treatment resulted in larger or more flowers on late flowers, which may enhance pollen dispersal and reproductive success, while the total seed mass was the same between treatments. The results indicate that the study species <i>R. raphanistrum</i>, <i>Sinapis arvensis</i> and <i>Brassica napus</i> have plastic responses in floral traits according to the present pollination level. The third aim was to determine how varying pollen load affects seed quality and offspring vigor. The results suggest that high pollen load had no positive effects on seed quality or offspring vigor due to pollen competition. Instead, seed mass determined seed quality and offspring vigor in the three study species and low pollen load treatment resulted in highquality offspring due to heavier seeds. The fourth aim was to examine causes and consequences of variation in reproductive success of <i>Succisa pratensis</i> on a regional scale. The results suggest that the most important variables, on a regional scale, for reproductive success were population size and habitat quality. The results showed that seed weight variation might be important when assessing reproductive success. In this study, seed weight variation did not seem to be adaptive.</p>

<p>Frivilliga avsättningar av skog med höga naturvärden är en viktig del för att nå Miljömålet ”Levande skogar”. Det finns dock tveksamheter om de naturvårdsbiologiska kvalitéerna i dessa avsättningar. Syftet med denna studie var därför att undersöka om den skog som avsätts frivilligt av privata skogsägare är den skogsmark som har de högsta naturvärdena på fastigheten. Vidare studerades också markägarens naturvårdskunnande, utbildningsnivå och attityd till naturvård. Detta kan påverka viljan att avsätta skog frivilligt, hur långsiktig avsättningen blir samt kvalitén på avsättningarna. Studien består av inventeringar på sex skogsfastigheter i Östergötland med frivilliga avsättningar, samt en enkätstudie till skogsägare. Det visade sig att skogsägarna i huvudsak avsatte de bestånd med högst naturvärde på fastigheten. Tre bestånd (en lövskog, en tallskog samt en källmiljö) av totalt 59 hyste högre naturvärde än de frivilligt avsatta. De avsatta skogarnas hade lägre virkestäthet än produktionsbestånden och bestod i större utsträckning av lövskog. Majoriteten av skogsägarna avsatte skogen långsiktigt för kommande generationer. När skogsägarna fick rangordna syftet med sin skogsfastighet prioriterades virke i första hand, naturvård värderades betydligt lägre. En mätning av kunskaper i tillämpad ekologi och artkännedom visade att skogsägarnas kunskaper i regel var bristfälliga när det gällde igenkänning av indikatorarter samt viktiga trädslag för artbevarande. Majoriteten av de som var negativa till att göra frivilliga avsättningar kunde tänka sig att ändra åsikt vid ”skälig ersättning”. Mer omfattande studier behövs för att avgöra om mina resultat var representativa och om de frivilliga avsättningarna verkligen hyser fastighetens högsta naturvärden och lever upp till miljömålet levande skogar.</p> / <p>Voluntarily protected forests with high nature conservation value are an important part of fulfilling the environmental objective "Sustainableforests". The aim of this study was to evaluate if the voluntarily protected forests are those with the highest conservation value for threatened species¹ on the estate. Another purpose was to investigate the knowledge in applied ecology among small-scale foresters, their educational level and attitudes towards conservation. The study contains inventories at six different estates in the county of Östergötland and a query targeted to small-scale forest owners. The foresters in my study set aside the areas with the highest conservation values on the estate with few exceptions. Three areas (one deciduous forest, one pine forest and a well) out of 59 had a higher conservation value than the areas set aside voluntarily. The voluntarily protected forests had less timber density than the productive areas and contained more deciduous forest. A majority of the foresters voluntarily protected forests where intended to remain for future generations. As part of my study the foresters also got to rank the purpose of the forest estate. Timber got the highest rank while nature conservation got a considerable lower rank. A measurement of the small-scale forester's knowledge in applied ecology and indicator species showed that their knowledge often was inadequate regarding indicator species. A majority of those negative to voluntary forest conservation areas on their own estate were willing to change view if they were given adequate economic compensation.</p><p>1 according to the Swedish Red list</p>

<p>The complex interplay between biotic and abiotic factors, believed to be responsible for several oak declines in European oak stands during the last three decades, remains poorly understood. Hence, this study aims at clarifying the temporal process of oak declines, as well as identifying individual tree and environmental variables that increase the risk of oak mortality. The study was performed in one of the few areas in northern Europe still holding high densities of old oaks (<em>Quercus robur </em>L<em>.</em>). Cross dating revealed that most trees had died during the last decade. Averaged chronologies and multiple chronological clustering suggested that the onset of the oak decline happened in 1992, when a severe drought took place. Two of the sites showed a rather short time period of heavily reduced growth prior to death, most likely caused by an insect defoliation in combination with a mildew infection of the replacement shoots. Environmental variables presented a rather weak influence on oak mortality. The results support the idea of attributing oak mortality to a combination of long- and short-term stresses, and emphasize the importance of including present as well as past factors when analysing the causes of oak declines.</p>

<p>This thesis focuses on mechanisms and processes underlying spatial patterns of resistance and virulence and on local adaptations in plant–parasite interactions. The model system used comprises the plant host Salix triandra, the pathogenic rust fungus Melampsora amygdalinae, the leaf beetle Gonioctena linnaeana, and the galler Pontania triandrae. In this work, I (1) emphasize the most important factors determining the outcome of a plant–pathogen interaction, and the types of systems in which local adaptations can be expected, (2) examine the resistance structures of different populations of S. triandra, and whether the leaf beetle G. linnaeana responds to the local conditions of the populations of S. triandra in Sweden, and (3) address whether the distribution of parasites on S. triandra can be explained by the plant content of secondary metabolites.</p><p>A review of several studies of the subject leads to the conclusion that adaptation of pathogens to their local hosts is more likely to be found in systems in which the pathogen is host-specific, non-systemic, and has a larger dispersal range and evolutionary potential than its host does. Furthermore, the scale of the study must be adjusted to that of the pathogen’s local population distribution. In addition, the temporary nature of host–pathogen interactions influences the importance of sample size, and too-small sample sizes can lower the chance of finding local adaptations, even though they may have evolved in a given system. The results of an inoculation experiment using material from physically isolated natural populations of S. triandra and M. amygdalinae confirm the importance of previous conclusions.</p><p>Spatial variation in the resistance structure of S. triandra also has effects on the insect herbivore G. linnaeana, which has responded by adapting to the local hosts. However, local differences in secondary chemistry affect different parasites in different ways, and while P. triandrae is attracted by high levels of phenolic compounds, including tannins, M. amygdalinae and G. linnaeana are more rarely found on plant individuals with high concentrations of tannins. In addition, brood deposition by adult females of G. linnaeana and the performance of larvae are positively affected by luteolin-7-glucoside and an additional unidentified flavonoid, whereas they are negatively affected by the presence of (+)-catechin and high levels of tannins.</p><p>Our results also show that plants traits that provide resistance to one type of parasite do not necessarily provide resistance to others. This indicates that different natural enemies potentially assert divergent selection pressure on S. triandra phenotypes which can be important for maintaining phenotypic variation in plant species.</p>

<p>There has been a long-term decline in number of cyclic vole populations in boreal Sweden since the 1970s. Several hypotheses have been suggested to explain this decline. Commonly for <i>C. glareolus</i>, <i>C. rufocanus</i> and <i>M. agrestis</i>, the decline has followed upon an increased frequency and severeness of winter declines and has shown up as a drop in spring densities. The spring decline is most pronounced for <i>C. rufocanus</i>. In contrast to other voles, <i>C. rufocanus</i> also show a decline in fall densities, suggesting some additional disturbance in this species. Habitat fragmentation has been suggested as such an additional disturbance and in this thesis the effect of habitat fragmentation on <i>C. rufocanus</i> is explored.</p><p>At first the sampling method was evaluated i.e. whether the decline could be due to destructive sampling when the method in use in the long-term monitoring is snap-trapping. This resulted in a rejection of the destructive sampling hypothesis as a possible cause behind the decline in <i>C. rufocanus</i>. Habitat preference revealed that three habitats at the local scale (trap station) were high quality habitats for <i>C. rufocanus</i>: forest of moist and wet/hydric dwarf-shrub type, in addition to forest/swamp complexes rich in dwarf-shrubs. The occurrence of <i>C. rufocanus</i> at the landscape scale was positively correlated with the amount of boulder fields and a low degree of fragmentation of old-growth pine forests. There was considerable local variation in the decline in vole density among the 58 1-ha sampling plots, with respect to both density and timing of the decline, which suggested that habitat destruction outside sampling plots might be involved. Overall, clear-cuts had a negative influence on vole densities at both the local and landscape scale. A multiple regression analysis suggested that having both a high quality habitat at the local scale and a high proximity among xeric-mesic mires and a low connectivity among clear-cuts at the landscape scale were important for the occurrence of <i>C. rufocanus</i>.</p><p>Initial analysis at the landscape scale were based on landscape data collected from 2.5 x 2.5 km areas centred on the individual vole sampling plots. Further investigations, however, on the patch level suggest that focal forest patch size and quality was of major importance in determining occurrence and persistence of <i>C. rufocanus</i>. Although not tested formally in these studies, the habitat fragmentation hypothesis has so far received support. Currently <i>C. rufocanus</i> seems to be affected negatively by too low patch sizes of suitable habitats in the surrounding landscape suggesting that the amount of suitable habitats could already be below the fragmentation threshold. However, this has to be evaluated further. Work is in progress to establish time-series over local landscape changes, and to evaluate if such changes have been associated with local declines of <i>C. rufocanus</i> and whether habitat loss, true habitat fragmentation or both have been influential.</p>

Pollination is one of the most important factors determining the reproductive success of plants. This thesis examines processes associated to varying pollination, with focus on plant responses. The first aim was to examine the possibility and constraints for short-term evolution of flower size in Raphanus raphanistrum. The results showed that there exists a possibility for pollinator-mediated short-term evolution of flower size in the study species. Flower size was strongly correlated to plant size. Since flower size cannot evolve separately from plant size, this correlation may constitute a constraint to the evolution of flower size. The second aim was to determine how varying pollen load affects later flowering, reproduction and growth of maternal plants. High pollen load treatment resulted in larger or more flowers on late flowers, which may enhance pollen dispersal and reproductive success, while the total seed mass was the same between treatments. The results indicate that the study species R. raphanistrum, Sinapis arvensis and Brassica napus have plastic responses in floral traits according to the present pollination level. The third aim was to determine how varying pollen load affects seed quality and offspring vigor. The results suggest that high pollen load had no positive effects on seed quality or offspring vigor due to pollen competition. Instead, seed mass determined seed quality and offspring vigor in the three study species and low pollen load treatment resulted in highquality offspring due to heavier seeds. The fourth aim was to examine causes and consequences of variation in reproductive success of Succisa pratensis on a regional scale. The results suggest that the most important variables, on a regional scale, for reproductive success were population size and habitat quality. The results showed that seed weight variation might be important when assessing reproductive success. In this study, seed weight variation did not seem to be adaptive.