Browsing by Subject "hyönteiset"

The purpose of this master's thesis was to study environmental impacts of nature-based tourism on vegetation, insect communities, birds and soil nitrogen levels in Käsivarsi wilderness area in the Finnish Lapland. Tourism is the largest industry in the world and nature-based tourism is the fastest growing segment of it. Nature-based tourism takes place in areas that holds great nature values. These areas are often protected to preserve significant nature values from negative impacts of human activities. This controversy creates disharmony between nature tourism and nature conservation. Most popular nature tourism destinations in Finland are state owned national parks and wilderness areas. Wilderness areas are not within strict nature conservation. They are areas defined by law for preserving the typical character of the remaining wilderness areas, preserving native Saami culture and for preserving and developing recreational use of these areas. Studies have shown that nature-based tourism has caused changes by erosion and human disturbance to vegetation, mammals and birds. The key study question was to examine if there are changes in the soil nitrogen levels around huts used by hikers. I was also a point of interest to discover what kind of bird, insect and plant communities occur around these huts. Main interest was to see if there are changes in these communities on a gradient from high human impact areas around the huts to more pristine mountainous areas. The study was performed around five huts with three study lines, which had study points 15, 30, 60, 120, 240, 480 and 960 meters away from the hut. Birds were observed from the same lines but with 200 meter point counting intervals. It was also studied whether the abundance of graminoids was affected by the soil nitrogen levels and if soil nitrogen levels or the abundance of graminoids influenced changes in insect or bird communities. Results show that nature-based tourism has an impact on soil ammonium and nitrate levels. This impact was visible in increased nitrate and ammonium levels on a 30 meter radius area around the huts. The observed fauna and flora around the huts were typical for the mountainous region in the northern Finland. There were no observed invasive species. No species was discovered to have a negative impact from nature-based tourism. Abundance of graminoids increased near the huts whereas plant species richness and vegetation biomass did not. The insect community was more diverse and abundant near the huts. Especially Amara brunnea ground beetle and rove beetles showed a clear increase in numbers near the huts. Birds were also more abundant and species rich near the huts. Especially insect eating bird species as a group were more abundant close to the hut compared to the surrounding study areas. The increased level of ammonium in the soil correlated with the increased graminoid and insect abundances. The increased graminoid abundance correlated also with the observed insect abundance. The influence between nature-based tourism and the changes in soils nitrogen levels and in the insect communities were scientifically demonstrated for the first time in this study. This thesis provides a comprehensive view of the effects that nature-based tourism has in the northern Finnish nature. The generalization of the result was weakened by the fact that the study was conducted only around five different huts and that the studied plant and animal communities were relatively diverse between these huts. The results are still substantial for the nature tourism in Käsivarsi wilderness area. The results can be useful for developing nature tourism infrastructure for the plausible new national park in the area.

Global surface temperature is increasing at an alarming rate. Local populations can cope with the change, if they have adaptive potential to face the new thermal regime. Hybridization with a closely related lineage is one potential source of adaptive genetic variability. My thesis aimed to investigate thermal adaptation by looking into thermal tolerance differences between two mound-building wood ants Formica polyctena and Formica aquilonia and their hybrids. The two parental species have distinct distributions: F. aquilonia can be found in Northern Europe while F. polyctena is distributed from Central Europe to Fennoscandia. The samples for this thesis were collected from a relatively small area in southern Finland and Åland Islands. Aim of my thesis was to clarify whether the two parental species have distinct thermal tolerances, which would reflect the differences in their distributions. I also tested whether hybrid individuals have wider thermal limits since they have alleles from both northern and southern parental species and could therefore show adaptive potential. I tested thermal tolerance differences with two temperature assays: heat-knockdown resistance and chill-coma recovery. I hypothesized that F. aquilonia would express more cold-tolerant thermal limits whereas F. polyctena would express more heat-tolerant limits. My results showed that the parental species differed in their thermal tolerance and expressed thermal limits which reflected their distribution. These results support the thermal adaptation hypothesis: parental species expressed thermal limits that reflected the thermal environment in their native habitat. The results also showed that hybrids could not combine the thermal tolerance of both parental species as they did not have wider thermal tolerance than parental species. Intriguingly, dry weight had a significant role in thermal tolerance, bigger ants coping better with higher temperatures. These results contribute to building up knowledge on the outcomes of hybridization and the potential that species possess in coping with the environmental change. Wood ants are keystone species in boreal forests and the findings of my thesis shed a light on the changes in population dynamics for these species in the face of global climate change.