0000000001150547
AUTHOR
Tomi Hakkari
showing 6 related works from this author
Effects of male removal on female foraging behavior in the Eurasian treecreeper
1997
In old, spruce-dominated forests of central Finland, Eurasian treecreepers Certhia familiaris divide their territories spatially during the breeding season. Females forage primarily on the upper parts of the tree trunks, while males use the lower parts of the tree trunks. In this study we removed males from eight territories in the early nestling period to see if the mate's absence would change the foraging patterns of the resident female. Widowed females foraged at lower heights, thus behaving more like paired males. These females also spent less time on each tree and on each foraging bout than did paired females. We conclude that male removal facilitated the change in a female's foraging …
Predicting valuable forest habitats using an indicator species for biodiversity
2020
Intensive management of boreal forests impairs forest biodiversity and species of old-growth forest. Effective measures to support biodiversity require detection of locations valuable for conservation. We applied species distribution models (SDMs) to a species of mature forest, the northern goshawk (Accipiter gentilis, goshawk), that is often associated with hotspots of forest biodiversity. We located optimal sites for the goshawk on a landscape scale, assessed their state under intensified logging operations and identified characteristics of goshawks' nesting sites in boreal forests. Optimal sites for the goshawk covered only 3.4% of the boreal landscape and were mostly located outside pro…
Behavioural responses of Eurasian treecreepers, Certhia familiaris, to competition with ants
1997
Competition for a specific resource that is essential for the survival of both the competitors may be intense even between very dissimilar taxa. However, the importance of the effects caused by such interspecific competition has seldom been emphasized. These effects can appear as differences in individual foraging behaviour during the breeding season, which can result in critical variation in fitness. In this study we examined the effects of wood ants (Formica rufa group) on the abundance of other invertebrates on tree trunks and on the foraging site selection of breeding Eurasian treecreepers, which use the same habitat as wood ants. Arthropods were scarcer on the trunks with ants present;…
Effects of habitat restoration on peatland bird communities
2020
Restoration of damaged ecosystems has become an important tool to slow down the biodiversity loss and to maintain ecosystem services. Peatland bird populations have shown a substantial decline during the recent decades in Northern Europe as a consequence of peatland drainage. We studied whether restoration of peatlands drained for forestry affects bird communities. We conducted bird surveys at 11 peatlands in Western Finland, where each of the restored and their pristine counterparts were surveyed before restoration and yearly after restoration during 2010–2018. We used linear mixed effect models to analyze whether restoration affected the number of species and territories of peatland speci…
REPRODUCTIVE SUCCESS OF EURASIAN TREECREEPERS,CERTHIA FAMILIARIS,LOWER IN TERRITORIES WITH WOOD ANTS
1999
Few studies have considered the effects of interspecific competition between distantly related taxa on the reproductive success of individuals. We compared the food supply, laying date, clutch size, and breeding success of a small double-brooded passerine bird, the Eurasian Treecreeper (Certhia familiaris) between territories with or without col- onies of red wood ants (Formica rufa group) during four years. Both the wood ants and Eurasian Treecreepers forage on tree trunks and utilize the same food resources. It has been shown that the wood ants are able to depress the available food supply for the treecreepers and interfere with their foraging behavior. We found that food abundance was lo…
Elinympäristöjen tilan edistäminen Suomessa : ELITE-työryhmän mietintö elinympäristöjen tilan edistämisen priorisointisuunnitelmaksi ja arvio suunnit…
2015
Kestävä luonnonvarojen käyttö on perusta sekä ihmisen että luonnon hyvinvoinnille. Tähän mietintöön on koottu Elinympäristöjen tilan edistämisen (ELITE) työryhmän työn tulokset. Työ edistää osaltaan luonnonvarojen käytön kestävyyttä antamalla suuntaviivoja luonnon monimuotoisuuden turvaamiseen Suomen metsissä, soilla, perinnebiotoopeilla, maatalousalueilla, kallioilla, tuntureilla sekä rannikolla. Osin tarkastelussa mukana olivat myös kaupunkiympäristöt ja sisävedet. Varsinaisen tarkastelun ulkopuolelle jätettiin rannikkovesien ulkopuoliset meret. Elinympäristöjen tilan edistämisen toimenpiteet voivat käsittää suojelua, luonnonhoitoa tai perinteisellä tavalla ymmärrettyä ennallistamista. To…