Sookure (Grus grus) pesakondade kodupiirkonna dünaamika
Laen...
Kuupäev
2026
Kättesaadavus
05.09.2026
Autorid
Ajakirja pealkiri
Ajakirja ISSN
Köite pealkiri
Kirjastaja
Eesti Maaülikool
Abstrakt
Sookurg (Grus grus) on Eestis ja Euroopas laiemalt oluline liik, kelle elupaigad on inimtegevuse ja maakasutuse muutuste tõttu pideva surve all. Varasemad uuringud on käsitlenud peamiselt liigi rändekäitumist, kuid kodupiirkondade dynäamika ning seos poegade arenguperioodiga on jäänud vähem uurituks. Käesoleva bakalaureusetöö eesmärk oli uurida sookurgede kodupiirkonna suuruse muutumist poegade lennuvõimestumise käigus ning hinnata pesakondadevahelist varieeruvust. Töö põhines 22 Eestis pesapojana märgistatud sookure GPS-jälgimisandmetel (2016–2024). Kodupiirkonnad arvutati autokorreleeritud tuumtiheduse hinnangu (AKDE) meetodil, eristades tuumikala (50% UD) ja kogu kodupiirkonda (95% UD). GPS-andmeid töödeldi R-keskkonnas ning statistilises analüüsis kasutati üldistatud aditiivseid mudeleid (GAM) ja lineaarseid segamudeleid (LME).
Tulemused näitasid, et sookurgede kodupiirkonna suurus muutus arenguperioodi jooksul selgelt ja mittelineaarselt. Mõlema UD taseme puhul eristus kolm faasi: lennuvõimetu periood, kiire suurenemise periood lennuvõimestumise ajal ning stabiliseerunud periood. Kogu kodupiirkond (95% UD) kasvas 72,5 hektarilt 369,9 hektarini ja tuumikala (50% UD) 17,3 hektarilt 87,4 hektarini (404,2%). Enne lennuvõimestumist oli nii kodupiirkond kui ka tuumikala oluliselt väiksem kui hilisemates perioodides (p < 0,002). Pesakondadevaheline varieeruvuse analüüs näitas, et ligikaudu 34% kodupiirkonna suuruse varieeruvusest oli seotud pesakondadevaheliste erinevustega (ICC = 0,342). Tulemused on rakendatavad sookure kaitse- ja majandamisstrateegiate kujundamisel, eriti sobivate ja rahulike elupaikade säilitamisel kogu pesitsusjokkeengse arenguperioodi vältel. Edasised uuringud võiksid keskenduda konkreetsete elupaigatüüpide, hooajalise maakasutuse ja inimhäiringute rollile sookurgede ruumikasutuse kujunemisel.
The Eurasian crane (Grus grus) is an important species in Estonia and across Europe, with habitats increasingly threatened by human activity and land-use change. Previous research has mainly focused on migratory behaviour, while the dynamics of home ranges during the fledging period have been less studied. The aim of this Bachelor’s thesis was to investigate changes in home range size during the fledging process of Eurasian crane chicks and to assess variation in home range size among different crane families. The study was based on GPS tracking data from 22 cranes ringed as chicks in Estonia between 2016 and 2024. Home ranges were calculated using the Autocorrelated Kernel Density Estimator (AKDE) method, distinguishing between core areas (50% UD) and total home ranges (95% UD). GPS data were processed in R using generalised additive models (GAM) to describe temporal change and linear mixed-effects models (LME) to assess between-family variation. The results showed that home range size changed clearly and non-linearly over the development period. Three phases were identified for both UD levels: a pre-fledging period, a rapid expansion phase during fledging, and a subsequent stabilised period at a higher level. The total home range (95% UD) grew from 72.5 ha to 369.9 ha, and the core area (50% UD) from 17.3 ha to 87.4 ha (404.2%). Approximately 34% of the variation in home range size was attributable to between-family differences (ICC = 0.342). The results are applicable in the development of conservation and management strategies for the species, particularly in maintaining suitable and undisturbed habitats throughout the post-breeding development period. Future research should focus on the role of specific habitat types, seasonal land use, and human disturbance in shaping crane spatial behaviour.
The Eurasian crane (Grus grus) is an important species in Estonia and across Europe, with habitats increasingly threatened by human activity and land-use change. Previous research has mainly focused on migratory behaviour, while the dynamics of home ranges during the fledging period have been less studied. The aim of this Bachelor’s thesis was to investigate changes in home range size during the fledging process of Eurasian crane chicks and to assess variation in home range size among different crane families. The study was based on GPS tracking data from 22 cranes ringed as chicks in Estonia between 2016 and 2024. Home ranges were calculated using the Autocorrelated Kernel Density Estimator (AKDE) method, distinguishing between core areas (50% UD) and total home ranges (95% UD). GPS data were processed in R using generalised additive models (GAM) to describe temporal change and linear mixed-effects models (LME) to assess between-family variation. The results showed that home range size changed clearly and non-linearly over the development period. Three phases were identified for both UD levels: a pre-fledging period, a rapid expansion phase during fledging, and a subsequent stabilised period at a higher level. The total home range (95% UD) grew from 72.5 ha to 369.9 ha, and the core area (50% UD) from 17.3 ha to 87.4 ha (404.2%). Approximately 34% of the variation in home range size was attributable to between-family differences (ICC = 0.342). The results are applicable in the development of conservation and management strategies for the species, particularly in maintaining suitable and undisturbed habitats throughout the post-breeding development period. Future research should focus on the role of specific habitat types, seasonal land use, and human disturbance in shaping crane spatial behaviour.
Kirjeldus
Bakalaureusetöö
Keskkonnakaitse õppekaval
Märksõnad
bakalaureusetööd, sookurg, AKDE, kodupiirkond, ICC, lennuvõimestumine