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Ornithology has a long tradition in biological research, and there are numerous data sets on various subtopics available both via scientific publications and conservation organizations. The phenology of migrating species (e.g. arrival dates to breeding grounds) has drawn attention in the last few decades, as it describes and helps understand effects of increasing temperatures on bird migration.

Since 1985 such corresponding data have been collected at Grimsö Wildlife Research Station. The dataset at Grimsö comprises of date of the first observation within the research area each year for ca. 80 migratory species, and shows several more or less pronounced changes over the 37 years of data collected.

Common cranes (Grus grus) migrating south for winter. Photo: Rick Heeres Common cranes (Grus grus) migrating south for winter. Photo: Rick Heeres

As expected, and seen in many studies, the long-distance migrants, that spend winter in, e.g. Africa, show very little variation in spring arrival dates between years (as seen in the graph below). In a few cases the date differs >1 week for such species, which is due to other factors than a sudden temperature change. Instead more or less the same dates/week are noted for them throughout the period. This behavior is explained in that the best timing of such long flights cannot be based on the daily weather in the wintering area, but is instead initiated mainly by day length, which in turn relates to a suitable arrival time at the breeding ground.  

Date (Julian day) of the first observation per year (since 1985) of the Common Cuckoo (Cuculus canorus) and the Barn Swallow (Hirundo rustica) within Grimsö Wildlife Research Area. Date (Julian day) of the first observation per year (since 1985) of the Common Cuckoo (Cuculus canorus) and the Barn Swallow (Hirundo rustica) within Grimsö Wildlife Research Area.

On the other hand, several of the migratory birds in Sweden that move only short distances, i.e. southward before the winter, move gradually in response to the local weather (temperature, food availability etc) and show significantly earlier spring arrivals in recent decades compared to the first years of the survey. The mean arrival dates of, for example, the Mallard and the Common black bird were 12 and 19 days earlier, respectively, in the period 2005-2022 and 1985-2004. Moreover, some of the short-distance migratory species nowadays stay in southern and middle Sweden throughout the winter.  

Date (Julian day) of the first observation per year (since 1985) of the Mallard (Anas platyrhynchos) and the Common blackbird (Turdus merula) within Grimsö Wildlife Research Area. The seasonal movements of these species are rather related to local weather conditions than actual migrations, with an apparent trend of earlier arrivals to the breeding grounds in later years. Points along the x-axis (i.e. Julian day = 0) indicate the bird species stayed in the area till the next year.

Here once again this dataset highlights the importance of long term monitoring. If this survey had started for example 10 years ago, we would not yet have recognized stark changes of bird arrivals in the region/data.

SITES Röbäcksdalen Field Research Station has recently welcomed researcher Julianne Oliveira! Welcome to the SITES Community, Julianne! 

Field dat being collected by Julianne Oliveira. Field dat being collected by Julianne Oliveira.

Julianne has a background in remote sensing, GIS and data science applied to agricultural and forest systems. She works with remotely sensed information (satellite, aerial and proximal sensors), field data collection and computer-based modelling to assess and monitor vegetation attributes. Her current research focus is to apply these approaches to forage crops in Northern Sweden. At SITES Röbäcksdalen Field Research Station, her role will be to support the team in the collection, management and analysis of the biological data to be published on the SITES Data Portal. She will also assist in the SITES Spectral activities at the station. Julianne is looking forward to collaborating with the team and assisting with the quality check and dissemination of the data. During her free time, she likes to travel and be outside, including activities such as hiking and running.

Asa High-yield Experimental Forest was established in 2009 and covers an area of 1700 hectares, situated in close proximity to Asa Research Station. Spruce and pine dominates the forest and represent 95% of the total area. The aim of the high-yield experiment is to increase the growth of wood by 50 %, and at the same time avoid creating any negative effects on water chemistry, vegetation, recreational values, etc. Every second year stands within the experimental area are fertilized. Due to the fertilization, water samples are collected and analysed regularly from streams that represent the different catchments within the area, to ensure that there isn’t leakage of nutrients.

Apart from producing water chemistry data from the different catchment areas, the water monitoring program gives an opportunity to follow the water level and discharge through the seasons. This year the water level has differed in comparison to earlier years. It is common that the streams in the forest run dry for a period during the summer, but this year, there has hardly been water in the streams during autumn. As the photo below shows, there is at the moment (in early November) hardly any or only very low flow in the streams.

Low water leves in Asa stream. Photo: Erik Kristensen

The graph below shows one of the streams drying up (i.e. very low discharge) by May and remaining that way into the autumn. March was extremely dry with minimal precipitation. Precipitation in the following six months was actually higher than the annual monthly average but it was still not enough to keep the stream flowing and make up for the lack of rain during March. The data is from an inlet stream to Lake Feresjön, where the water table has been low for a prolonged period, yet this year was even lower.

Water leve data from the Lake Feresjön inlet streams can be found on SITES data portal, and soon it will also be possible to download all water level data and water discharge data from the catchment areas in Asa High-yield Experimental Forest.

Lund University has recently installed two new spectral masts overlooking crop fields in Alnarp, near the SITES Lönnstorp Research Station. Each mast holds two down-looking spectral sensors, one on each side of the mast, overlooking one field each. There are also temperature and soil moisture sensors to follow the weather and climate at the locations continuously through time. The installations are part of a research project sponsored by the Swedish National Space Agency that aims to develop and quantify crop growth and yield based on satellite remote sensing. Accurate field measurements of biomass allocation to root, stem, leaves and seeds have been carried out through the season of 2022 and will form the basis of crop-growth modelling as a support to yield estimation. The stations are affiliated to the SITES Spectral infrastructure and will also provide an input to the Nordic NordPlant collaboration project focusing on plant phenotyping. For more information on the research, contact Lars Eklundh (

Installing the two new spectral mast on agricultural fields in Alnarp. Photo: Lars Eklundh.

A new article focusing on one of the main research fields of Bolmen’s Research Station recently got published in Water Practice & Technology. The article focuses on short-term changes of organic matter in Lake Bolmen, which has direct influences on the color of the water as well as the source water quality for drinking water production in south-western Skåne. Analysis of Kafjorden, a southern sub-basin of Lake Bolmen, was analyzed in detail and it was concluded that it can produce changes of organic matter in a time span of days to weeks. These changes are related to local inflow conditions of Murån, a sub-basin of the main tributary, as well as internal processes like sedimentation and wave driven resuspension.

Karfjorden, a southern sub-basin of Lake Bolmen. Photo: Clemens Klante Karfjorden, a southern sub-basin of Lake Bolmen. Photo: Clemens Klante

Information on how and when variations in organic matter happen in the lake does not only help to improve the drinking water treatment process downstream but it also effects the carbon dioxide (CO2) and waste production of such facilities. The article points out that better source water monitoring is a necessity to enable further analysis, which will not only further help to streamline water treatment efforts but also help to better understand water resources and its interactions. Infrastructures like SITES are a cornerstone to facilitate such vastly needed measurements.

Read the full article: Klante C., Hägg K., Larson M. 2022. Understanding short-term organic matter fluctuations to optimize drinking water treatment. Water Practice and Technology: 17: 2141–2159.

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