Fieldwork Notes from Slovenia

Written 7th July, 2022

As I sit sheltering from yet another incredible Alpine thunderstorm, I am given a chance to reflect on my time in Slovenia. To say this country is amazing would be an understatement; if you look on a map, you see the country is speckled with jagged mountain peaks and criss-crossed with meandering, emerald rivers.

 The latter is the reason I am here. I am an ecology undergraduate, researching how hydropower dams affect pollinator abundance along the river banks. Whilst dams may appear to be a source of green energy, many in fact do not harness a justifiable amount of hydroelectricity for the environmental destruction they cause.

 They also divide rivers, and consequently both the ecosystems and people who depend on them. Recently, the Albanian government committed to designating the Vjosa, one of Europe's last major undammed, wild rivers, a national park - a historic step which will see the creation of the continent's first river national park. In many countries, dams are being deconstructed if they are unused or too small to warrant their existence. The Sindi Dam was removed from the Pärnu River in Estonia in 2019, Europe's biggest dam removal project, and has seen habitats flourish back to life.

 Nevertheless, there is still an ongoing building spree of dams across the continent. Often construction projects are given the go-ahead where solid biodiversity data is missing, since there is no proof that there will be environmental consequences.

This is where my research slots in: whilst a lot of studies have quantified the effects of dams on aquatic species (particularly fish) and vegetation, little has been done on invertebrates. To my knowledge, no data exists on the effects of dams on pollinators around rivers. It is known that riparian habitats (riverbanks, to me and you) are important for insects thanks to the nutrients supplied by the river supporting a high diversity of flowers and other plants. Research has also shown that dams negatively affect vegetation. So I decided to link the two, and investigate whether I could quantitively show that dams affect pollinators too, the tiny superheros of wider biodiversity.

 This took me to the Sava River, in Slovenia. It is a beautiful river supporting a diverse range of ecosystems, from virgin forests to alpine meadows to floodplains. Slovenia is also known for its rich nature: around 60% of the country is covered by forest (by comparison, the UK averages 13%). I can't lie though, the mountain lover in me has been itching to visit for a while...

 The data collection was much harder than I expected. Starting out from camp, it would typically be a 2 or 3 hour hike to the locations I had chosen to study, then another few hours scouting out the area and picking the best points to do transects. These are how I collected information about pollinators; I would measure out 100 metres, then walk along and note down all the pollinators along this stretch. (For my research, I was only counting bees, wasps, flies, butterflies, moths and beetles, though birds and bats often also pollinate flowers.) I would take several transects both upstream and downstream of the dams, then compare them. I am yet to start any proper statistical analysis, but the numbers look promising...

 All this in over 30C heat, climbing around 1,000 metres in elevation and being out for around 12 hours every day has left me shattered, but invigorated. Whenever I finished collecting data, I would instantly take the opportunity to climb a nearby peak to end the day on a literal high. I was based in the Karavank mountain range, a delightful mixture of bare rock and pasture-covered peaks dividing Austria and Slovenia, dotted with alpine meadows and dense pine forests. These mountains certainly taught me a few lessons; I even got caught in a flash storm whilst descending Stol, the highest peak in the range. But as I sat on my final night on a secluded ridge overlooking the valley below with the emerald Sava meandering its way through, the intoxicating smell of pine filling my senses, I was filled with a mixture of awe for the landscape around me, and hope that these rich ecosystems will yet outlast us.