In memoriam Dr Aat Barendregt
Our former colleague Aat Barendregt passed away on 4 September 2022. Aat worked at the Environmental Sciences group - which started as an inter-faculty working group and later grew into part of the Copernicus Institute of Sustainable Development - from 1984 until his retirement in 2017. There he devoted himself with great energy and dedication to research and academic teaching for over 33 years, staying on as a guest researcher after his retirement up until the present day.
We knew Aat as an enthusiastic ecologist who easily switched between very diverse ecosystems. The main topic during his doctoral studies, also at Utrecht University, was vegetation science in which he investigated the vegetation of Zwanenwater near Callantsoog. After his graduation in 1981 (cum laude) he performed field work in Portugal’s coastal heathlands and produced an overview of western European heathland vegetation, as a researcher at Utrecht University. During his tenure as assistant professor he kept permanent quadrats in Zwanenwater for over 30 years, and with his net he followed the hoverfly route in Boeschoten in the Veluwe for 40 years. In 2022 he published an important article about this in the journal Insect Conservation and Diversity entitled “Forest hoverfly community collapse: Abundance and species richness drop over four decades”. Hoverflies were his specialty; the hoverfly table featured in Barendregt (1978) published by the Jeugdbonduitgeverij (JBU) is a well-known determination key.
In 1984, he started ecological modeling of aquatic and marsh plants, delving into the lowland fens of the Vecht region, and later into the pristine swamps, peat bogs and rivers of Biebrza and Narew in Poland. This led to the publication of many beautiful landscape ecology and eco-hydrological analyzes that make use of succession series and historical series of water quality, polder levels and plants and animals. About 20 years ago came a new love: freshwater tidal areas in the Biesbosch, Elbe and Chesapeake Bay, with several important publications about this extraordinary landscape system and an impressive book Tidal Freshwater Wetlands (2009) following suite.
Aat made a name for himself with his widely used ICHORS models, which he invented together with Jacques de Smidt. A request from the province of Noord-Holland was the impetus for the development of these models, which stand for Influence of Chemical and Hydrological Environmental Factors on the Response of Species. Many more requests followed and ICHORS boomed under his leadership. For these models, water and vegetation samples were collected at hundreds of locations around North Holland and later also Utrecht, Flevoland, South Holland and Groningen. Using logistic regression, he modeled the relationship between species and the environment, with an emphasis on water quality. This was innovative in ecology at the time, and the enormous data sets that formed the basis of these models were particularly impressive. These measurement-based models gave Dutch provinces insight into the reality of plant species decline in rural areas. With the results the provinces could draw up convincing policies for better water management, shutting down or relocating drinking water abstractions, better land use planning and for limitations to farmer fertilizer use.
We also knew Aat as an inspiring teacher who taught many different types of courses and contributed a great deal to education management and development. Examples include the development of the Vrije Studierichting Milieukunde curriculum (later the Bachelor's in Environmental Sciences), and of the Master's in Natural Resource Management. Among other things, he was the curriculum committee chair of these programs and of the education committee of Environmental Sciences. He was also coordinator of the Environmental Sciences Bachelor’s, the department’s Honors Program, and the Bachelor’s education assessment in 2012. He was also laboratory coordinator and managed the institute’s fieldwork equipment. In total, he bore ultimate responsibility for approximately 18 university courses. A selection of these include 'Practical Natural Resource Management', 'Interdisciplinary Project Evaluation', 'Environmental Advice Project', 'Sustainable Development', 'Landscape Ecology and Nature Conservation', 'Processes in Environmental Compartments' with the annual fieldwork in Tiengemeten, 'Research skills 2', and 'Environment, Behavior and Communication'. Aat also developed the Summer Course ‘Aqua’ together with Rob Klaassen, Margien Bootsma and European Students’ Forum (AEGEE), which was followed by a large group of foreign students every summer from 1993 to 2004. He supervised an estimated 50 bachelor and 30 master students theses.
Most of all Aat loved taking students and young researchers into the field to teach them how to read the landscape and show them which species are characteristic to particular habitats and the environmental factors that determine this. Besides being an expert in plants, vegetation and hoverflies, he was above all a holistic scientist. He never narrowed himself down to a reductionist expert, but always sought out the adventure of coherence - the relationships between different species and between species and their environment, of course including humans.
To the group he was a colorful colleague and team player - critical but always constructive, loyal to his work and faithful to the people he worked with. He was averse to pomposity and took no notice of hierarchy, he was relatable and level-headed, but combative when it came to nature and the environment. We will miss Aat, but remember him forever.
on behalf of the staff of the Copernicus Institute of Sustainable Development