Predicting valuable forest habitats using an indicator species for biodiversity

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 protected areas, which highlights the importance of conservation actions in privately-owned forests. Furthermore, optimal sites for the goshawk and associated biodiversity were under threat. Half of them were logged to some extent and 10% were already lost or notably deteriorated due to logging shortly after 2015 for which our models were calibrated. Habitat suitability for the goshawk increased with increasing volume of Norway spruce (Picea abies) peaking at 220 m(3) ha(-1), and with small quantities of birches (Betula spp.) and other broad-leaved trees. Threats to biodiversity of mature spruce forests are likely to accelerate in the future with increasing logging pressures and shorter rotation periods. Logging should be directed less to forests with high biodiversity. Continuous supply of mature spruce forests in the landscape should be secured with a denser network of protected areas and measures that aid in sparing large entities of mature forest on privately-owned land.peerReviewe

Kanahaukan pesäpaikkojen ennustaminen paikkatietoanalyysillä

Kanahaukka (Accipiter gentilis) on Suomessa silmälläpidettäväksi (NT) luokiteltu keskikokoinen päiväpetolintu, joka pesii varttuneissa metsissä. Kanahaukan valitsemat pesämetsät ovat todettuja monimuotoisuuskohteita. Kanahaukka onkin monella tapaa metsien avainlaji. Tämän takia oli tarpeen selvittää kanahaukan tyypillisen pesämetsän piirteitä mahdollisen elinympäristöjen suojelun kohdistamiseksi niille alueille, joilla saavutetaan monimuotoisuudelle suotuisin suojelutulos. Tässä tutkimuksessa tunnistettiin maksimientropiamallinnuksella kanahaukalle tärkeitä elinympäristömuuttujia ja paikannettiin lajille todennäköisesti sopivia metsiä maisematasolla Keski-Suomen alueella MaxEnt-ohjelmalla Luonnonvarakeskuksen valtakunnan metsien inventointiin liittyvän monilähdetietoaineiston perusteella. Lisäksi tutkittiin RandomForest-luokittelun avulla eroja pesäpisteiden ja satunnaispisteiden ympäristössä eri mittakaavoilla. Havaittiin, että parhaiten kanahaukan pesimisympäristöksi sopii sekapuustoinen metsä, jossa on kuusta yli 150 m3/ha. Maksimientropiamallinnuksen mukaan kanahaukan pesimisympäristöksi erinomaisesti tai hyvin sopivaa metsää oli 8 – 9 % Keski-Suomen maapinta-alasta. Maksimientropiamallinnus todettiin käytettävissä olleen aineiston puutteet huomioitaessa tämän työn analysointeihin paremmin soveltuvaksi menetelmäksi. Maksimientropiamallinnuksen tuottamia kanahaukalle parhaiten sopivia elinympäristömuuttujien arvoja ja todennäköisimpiä hyvän kanahaukkametsän sijainteja voidaan käyttää suunniteltaessa kanahaukan suojelutoimenpiteitä.The Northern Goshawk (Accipiter gentilis, hereafter Goshawk) is a medium sized bird of prey species, that breeds in mature forests and is classified as nearly threatened (NT) in Finland. The Goshawk indicates forest biodiversity as many threatened species are present in sites that the Goshawk uses for nesting. Therefore, it is important to study forest characteristics typical for Goshawk’s nesting sites in managed forests in order to be able to locate and to target conservation efforts to sites with potentially high biodiversity. In this study, data from National Forest Inventory (NFI) were analyzed with maximum entropy modelling of species’ distributions using the MaxEnt program to identify environmental characteristics typical of the Goshawk’s nest sites, and to locate forests likely suitable for Goshawk nesting within the region of Central Finland. In addition, nest site selection of the Goshawk was studied by detecting differences in habitats between the surroundings of Goshawk’s nest sites and randomly selected forested locations with Random Forest classifier using forest patch inventories and other geographic data from multiple sources. According to my results, the Goshawk prefers forests with a minimum of 150 m3/ha of spruce mixed with some deciduous trees as a nesting habitat. Of the land area of the region of Central Finland, about 8 to 9 % was designated excellent or suitable for Goshawk nesting