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1.
Abstract – A total of 40 (20 age-3 + 20 age-4) radio-tagged hatchery-reared brown trout ( Salmo trutta L.) and 40 wild radio-tagged northern pike ( Esox lucius L.) were released into a regulated river. Age-3 brown trout were predicted and observed to be highly vulnerable to predation by pike (50% mortality), whereas age-4 brown trout were predicted and observed to enjoy an almost absolute size refuge from predation (5% mortality). Almost half of the fish from both age groups similarly emigrated and survived from the river within 3 days of the release. However, there was a considerable difference in survival between age groups for fish that remained in the river for a longer period. Of these, all except one age-3 brown trout were eaten by pike, whereas all but one age-4 fish survived predation. 相似文献
2.
Tanja Myllyviita Teppo Hujala Annika Kangas Kyle Eyvindson Susanna Sironen Pekka Leskinen 《Scandinavian Journal of Forest Research》2014,29(7):20-29
Multi-objective forest planning is a multi-methodological endeavor whose success largely depends on how well the combined use of different methods contributes to the goals of the planning. This review assessed the benefits of mixing methods in natural resources planning. A sample of 30 peer-reviewed research articles was analyzed using an evaluation framework, designed based on democracy and planning theories, and participatory planning literature, including four dimensions: transparency, flexibility, consensus building, and operability. According to analyses, mixing different types (i.e. qualitative and quantitative) of methods generally yields greater benefits than the combination of similar methods. The subsample of 12 planning cases that utilized simulation-optimization software (SOS) appeared operable and moderately transparent, whereas flexibility and consensus building were often lacking. In comparison to the wide scholarly discussion on multi-methodology and mixing methods, it was observed that successful mixing examples in natural resource planning are still scarce and there are weaknesses in bridging the methods together. There is an evident need to pursue and to better communicate the benefits of mixing. Some good mixing examples utilizing SOS provided evidence that forest planning processes would make an excellent venue for studying the benefits and caveats of using mixed methods. 相似文献
3.
Abstract – We used radio telemetry to measure the habitat use and movements of 20 tagged pikeperch (44–59 cm) in the hydropeaking Pyhäkoski Reservoir, Finland, during June 1999–2000. The hydrological conditions in the 8-km-long reservoir were measured and then modeled over eight discharge rates between 30 and 700 m3 · s−1 . Pikeperch preferred relatively low water velocities and deep water depths especially during the winter. During the summer, pikeperch moved actively in different parts of the reservoir. No relationship was found between hydroelectric plant operations and distances moved by pikeperch during the summer. Movements peaked in autumn but decreased during the winter to a restricted area. After 1 year of monitoring, 4 out of 20 tagged pikeperch remained in the Pyhäkoski Reservoir, three had died when descending from hydroelectric dams, 10 had descended downstream to other reservoirs or sea, two were captured by local fishermen, and one fish's signal was lost for unknown reasons. 相似文献
4.
Abstract – We performed a tagging study on one of the spawning populations of northern pike ( Esox lucius L.) of the River Kajaaninjoki in Finland. Northern pike is the main predator in many lakes and rivers in the northern hemisphere. Previous tagging studies have shown a general tendency to sedentary behaviour by pike. Whether individuals in a fish population adapt a sedentary or moving strategy may affect population persistence. To study if the spawning population consists of sedentary or moving individuals and the pattern of movements, we tagged 40 pike with radio transmitters and followed them from May 2002 to June 2003. Pike were caught and tagged during the spawning season in the mouth of the River Kajaaninjoki which flows into one of the largest lakes in Finland, Lake Oulujärvi. Our results suggest that the pike spawning population consisted of sedentary pike ( N = 16) dwelling the whole year in the river, and moving pike ( N = 24) which moved to Lake Oulujärvi after the spawning period. Pike exhibited homing behaviour, as most of the migrating pike returned to the same spawning area in the following year. Large pike had a higher movement rate than small pike during the summer and seasonally the movement rate was lowest during the spring and highest during the summer. 相似文献
5.
Empirical forest owner classifications typically distinguish groups based on owners’ behaviour or motivations. Typologies are used to inform forest and environmental policies and market-based service provision. However, single typologies may be weak in discerning owner groups that would bring new insights for policymakers or service providers. The present study aims to put together two previously documented owner classification frameworks to form and analyse customer segments for decision-support services. The first grouping is based on owners’ objectives for forest ownership, while the second grouping focuses on owners’ decision-making styles. These two typologies deal with subjects of interest and motivations for communication, respectively. The study uses a subsample of the Finnish Forest Owner 2010 survey data, collected in 2009 (n = 2,106). Via cross-tabulation of the two groupings, the four largest and potentially most interesting combined owner groups are discerned: multiobjective learners (13 %), multiobjective thinkers (9 %), learning recreationists (8 %) and learning investors (7 %), while the other 16 combined groups each account for less than 6 % of owners. The result thus reveals the need for learning-oriented services for three differing principal subjects of interest as well as multiobjective services for deliberate thinkers, i.e. comparative information about forest management alternatives. The message for policymakers and service providers is that the majority of forest owners may be served with educative interactive services. Learning-oriented indifferent owners need special services to recognize their latent goals. Delegators need ready-made services for outsourced decision making and self-reliant owners need information packages of varying contents. Combinations of groups prove feasible for producing policy advice. 相似文献
6.
This paper examines the historical phases of Finnish forest planning from the 1960s to the present day in support of the rational
future development of forest planning for family-owned forest holdings. The ‘historical types’ of work—craft work, mass production,
process enhancement, and mass customization have been recognized in the Finnish planning discourse to date. Indications of
mass customization are typical in the present developmental discussion of forest planning. There are some signals in the current
planning debate that are calling for the next activity principle, co-configuration. A forthcoming type of forestry extension
activity, labelled adaptive planning, is described in this paper to explicate the demands imposed by a future planning system.
The present analysis informs also other contexts outside of Finland, where public and private institutions that support family
forest owners face post-industrial challenges. 相似文献
7.
The conservation, management and monitoring of aquatic resources should benefit from understanding their spatial structuring. In this paper, we used the reference condition approach (RCA) to test if the variability in biotic communities, riverine fish assemblages in the present case, is better controlled with a spatial delineation based on ecoregions or by grouping rivers with local catchment characteristics. Electrofishing data from 493 riffles in 99 rivers in Finland were used in the analysis. We completed multivariate analyses (nonmetric multidimensional scaling, multiresponse permutation procedures) to identify differences in fish community composition among groups based on ecoregions or catchment characteristics. We concluded that both regional processes and local environmental characteristics structured fish populations, and bioassessment of freshwaters should be based on regional spatial delineations, supported by local scale characteristics. Spatial delineations like ecoregions should be used to assist the bioassessment to improve the efficiency to detect the human impacts. 相似文献
8.
Malinen Jukka; Kilpelainen Harri; Piira Teppo; Redsven Visa; Wall Tapio; Nuutinen Tuula 《Forestry》2007,80(3):309-321
The aim of the study was to compare model-based approaches inthe prediction of timber assortment recovery with bucking simulationbased on detailed stem data. A correction function for the totallength of saw log fragments and two optional saw log reductionmodels, that is, the MELA96 version and MELA05 version, wereapplied. In the bucking simulation, the volumes by timber assortmentswere calculated using a bucking-to-value simulator. The predictionof saw log recoveries varied between the bucking simulationand different versions of saw log reduction models. The levelof the reduction from the MELA96 version was at the same levelas from the bucking simulation where defects were taken intoaccount, but the saw log reduction had a very low variance dueto a small amount of independent variables. The saw log reductionof the MELA05 version included more variation although the levelof the reductions was higher and the variation did not meetwith the bucking simulation. As a conclusion, the model-basedapproaches seem applicable at least for the prediction of sawlog recovery in the large area forest inventories where thevariance of the standwise timber assortment recoveries neednot be predicted. 相似文献
9.
Protecting biodiversity within separate set-aside conservation areas has not been effective enough to halt its loss. Thus, new approaches to conserve biodiversity alongside production are needed. The non-market values of a forest may play an essential role when the forest owner decides the use of their land. However, so far the service offerings other than related to timber production, have been scant. The mismatch between decision support services offered and the service interests of forest owners may result in the objectives of forest owners remaining unfulfilled. The aims of this study were to explore the links between family forest owners’ forest management preferences and their objectives for the forest and secondly their preferences for decision support services. Data were collected in a postal survey in the Northern Karelia region, Finland in spring 2014. Data consist of 298 survey answers that were analysed using multi-variate analyses. Two typologies were combined: clustering of forest ownership objectives and the preferred forest management style. We found that the forest owner’s objectives were demonstrated by their preferred way of managing the forest. Opinions about different decision aid services varied between cluster groups. The groups emphasizing nature values considered biodiversity related information about their forest more necessary than other groups. They were also less satisfied with the usability of the forest management plan. Forest advisory services should better acknowledge the prevalence of multiple objectives also among forest owners who are interested in timber selling. Developing services for forest owners with diverse socio-economic backgrounds, information needs and objectives is important. 相似文献
10.
Viitmaa R Cizinauskas S Bergamasco LA Kuusela E Pascoe P Teppo AM Jokinen TS Kivisaari L Snellman M 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2006,20(2):305-310
Eleven Finnish Spitz dogs with focal seizures and 3 healthy controls were evaluated. General clinical and neurological examinations, blood examination, urinalysis, cerebrospinal fluid examination, electroencephalography (EEG), and magnetic resonance imaging (MRI) of the brain were performed on all dogs. On EEG examination, focal epileptic activity was found in 7 of 11 dogs (64%), and generalized epileptic activity was observed in 4 of 11 dogs (36%). MRI (performed with 1.5 T equipment) detected changes in 1 epileptic dog. Mild contrast enhancement after gadolinium injection was identified in this dog's right parietal cortex. However, no such changes were observed in repeated magnetic resonance images. Special emphasis was given to seizure history to determine any correlations between seizure intervals and MRI findings. Our results indicate that Finnish Spitz dogs with focal seizures suffer from focal idiopathic epilepsy and have nondetectable findings on MRI or pathology. MRI showed poor sensitivity in detecting epileptogenic areas in our patients with focal seizures. Reversible MRI changes in 1 dog could have been caused by seizures. 相似文献