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David Kleijn

@davidkleijn

Conservation ecologist, Pollinator afficionado, Wageningen University

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22.03.2025
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Latest posts by David Kleijn @davidkleijn

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However, based on my experiences here, I would say that multi-actor or codesign approaches are not the miracle cure to solve the biodiversity crisis that many hope they are πŸ™πŸ™

29.12.2025 16:28 πŸ‘ 2 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0
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Kudos, to all partners for achieving this conservation success and to Klara Leander Oh for writing a great paper

29.12.2025 16:28 πŸ‘ 0 πŸ” 0 πŸ’¬ 1 πŸ“Œ 0
Redirecting

First ever evidence that multi-actor collaborative conservation produces biodiversity benefits (as far as I know) doi.org/10.1016/j.bi...

29.12.2025 16:28 πŸ‘ 10 πŸ” 6 πŸ’¬ 1 πŸ“Œ 0

Semi-natural habitats are key for farmland biodiversity but their quality is often low due to high exposure to fertilizers 🌾πŸ§ͺ

A new study shows that more frequent cutting can create diverse vegetation even in highly productive habitats βœ‚οΈπŸŒ

πŸ”— doi.org/10.1111/1365...

04.11.2025 17:00 πŸ‘ 9 πŸ” 4 πŸ’¬ 0 πŸ“Œ 2

Removing cut vegetation is important for maintaining species rich and flowering vegetation. When having too choose between these machines and not removing the cuttings or not cutting at all I pick the machines any time.

16.11.2025 16:11 πŸ‘ 3 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0
Geographical distribution of observations from studies included in the final analysis. Circle size is scaled for visualization purposes to improve visibility of overlapping data points, and does not encode any quantitive information. The center of each circle corresponds to the coordinates of the reseach area of the included studies.

Geographical distribution of observations from studies included in the final analysis. Circle size is scaled for visualization purposes to improve visibility of overlapping data points, and does not encode any quantitive information. The center of each circle corresponds to the coordinates of the reseach area of the included studies.

Probabilities of observing an increase or no change in biodiversity upon conservation of extensively managed grasslands, and of observing an increase in biodiversity after restoration of previously abandoned or intensively used agriculturally marginal grasslands. Numbers indicate sample sizes. Raw data are overlaid as jittered points to show the distribution of observed outcomes that informed the model.

Probabilities of observing an increase or no change in biodiversity upon conservation of extensively managed grasslands, and of observing an increase in biodiversity after restoration of previously abandoned or intensively used agriculturally marginal grasslands. Numbers indicate sample sizes. Raw data are overlaid as jittered points to show the distribution of observed outcomes that informed the model.

🌿πŸͺΆ New Review in #BAAE: Abandonment & intensification impact biodiversity in marginal grasslands.

Across 174 European studies, both pathways reduced diversity β€” while restoration & extensive management help recover ecological value. 🌾

DOI: doi.org/10.1016/j.ba...
@gfoesoc.bsky.social

02.11.2025 07:00 πŸ‘ 12 πŸ” 8 πŸ’¬ 0 πŸ“Œ 0
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The winners take it all: het effect van intensief landgebruik op insecten Nieuw onderzoek laat zien wat het steeds intensievere gebruik van grasland betekent voor insecten. Verrassend genoeg bleef bij intensiever gebruik het totale aantal insecten stabiel, maar de soortenrijkdom halveerde. Dit komt doordat soorten verschillend reageren. 85 procent van de soorten ging achteruit en de meeste verdwenen volledig, maar een paar wijdverspreide soorten profiteerden.
25.10.2025 10:01 πŸ‘ 5 πŸ” 5 πŸ’¬ 0 πŸ“Œ 0
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Fall ❀️

12.10.2025 15:50 πŸ‘ 3 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0

Great new study by Reinier de Vries (and others), who caught 170,000 individuals and identified 27,200 of them to species level. Makes you understand why few studies have done this so far.

10.10.2025 12:05 πŸ‘ 5 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0
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Intensifying grassland management leads to massive loss of arthropod species. However, total arthropod numbers remain more or less stable. Many losers, few winners. doi.org/10.1016/j.bi...

10.10.2025 12:05 πŸ‘ 39 πŸ” 14 πŸ’¬ 1 πŸ“Œ 0
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Mixed plant and arthropod biodiversity responses to solar park establishment on former agricultural lands πŸ¦‹

Suggests that, while biodiversity can increase in solar parks post-conversion compared to previous land use, not all taxonomic groups benefit from this change 🌏πŸ§ͺ

doi.org/10.1111/1365...

08.10.2025 11:02 πŸ‘ 18 πŸ” 8 πŸ’¬ 0 πŸ“Œ 0
Four graphs comparing species richness at various taxonomic levels

Four graphs comparing species richness at various taxonomic levels

A welcome research comparing the results of pollinator monitoring obtained by humans (so-called 'pollination ecologists') and concurrent time-lapse videos (so-called 'the future for lazy' 😜). Take a quick glance at this figure from the paper and judge for yourself

doi.org/10.1002/aps3...

01.10.2025 12:03 πŸ‘ 39 πŸ” 9 πŸ’¬ 3 πŸ“Œ 0

Politics is complicated

Business is complicated

Finance is complicated

So why do they all expect ecologists to come up with simple actions & metrics for nature recovery

Could they be spinning us a line?

27.09.2025 08:03 πŸ‘ 8 πŸ” 2 πŸ’¬ 2 πŸ“Œ 0
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Finished data collection for this paper 19 years ago 🫣

27.09.2025 16:01 πŸ‘ 6 πŸ” 0 πŸ’¬ 1 πŸ“Œ 0
Home Page

Important to promote farmland wildlife, but this paper in Science, (doi.org/10.1126/scie...) published 2 days ago, highlights that in intensive agricultural landscapes we first need MORE habitat before we put effort in enhancing quality

27.09.2025 16:01 πŸ‘ 4 πŸ” 1 πŸ’¬ 1 πŸ“Œ 0
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Higher cutting frequency can restore habitat quality on farmland. doi.org/10.1111/1365...

27.09.2025 16:01 πŸ‘ 8 πŸ” 6 πŸ’¬ 2 πŸ“Œ 0
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Dutch solar parks approach pollinator & plant biodiversity levels of extensive grasslands, but only on the surface not covered by panels. Soil-emergent arthropods and butterflies lack behind. Proud of Timea for leading besjournals.onlinelibrary.wiley.com/doi/10.1111/...
@jappliedecology.bsky.social

23.09.2025 08:37 πŸ‘ 24 πŸ” 10 πŸ’¬ 1 πŸ“Œ 0
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Using total abundance as a proxy for wild bee species richness: A practical tool for non-experts 🐝🌏

Proposes that employing an effective proxy for non-experts could enhance the evaluation of many local and regional conservation initiatives πŸ“‘πŸ§ͺ

πŸ”— doi.org/10.1111/1365...

25.09.2025 13:02 πŸ‘ 9 πŸ” 5 πŸ’¬ 0 πŸ“Œ 0
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Veel meer natuur nodig om nuttige insecten voor de landbouw te behouden Regels van de EU die tot herstel van de insectenpopulatie moeten leiden zijn ontoereikend, blijkt uit Wagenings onderzoek dat donderdag gepubliceerd is in het wetenschappelijke tijdschrift Science.

Veel meer natuur nodig om nuttige insecten voor de landbouw te behouden

25.09.2025 18:03 πŸ‘ 109 πŸ” 56 πŸ’¬ 3 πŸ“Œ 4
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Met 10 procent leefgebied herstellen bestuivers niet Bijen, hommels en vlinders hebben te weinig natuur om zich heen om te overleven. Uit recent, in Science gepubliceerd, onderzoek onder leiding van een onderzoeksteam van Wageningen University & Research blijkt dat deze insecten veel meer ruimte nodig hebben om te herstellen dan nu in EU-richtlijnen is vastgelegd. Ook blijkt de kwaliteit van die ruimte belangrijk om mee te nemen.
25.09.2025 18:02 πŸ‘ 32 πŸ” 18 πŸ’¬ 0 πŸ“Œ 1
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We need much more semi-natural habitat (6-37%, depending on species group) in agricultural landscapes to effectively conserve pollinators. Large collaborative synthesis study looking at 59 studies in 1250 landscapes from 19 countries now published in Science www.science.org/doi/10.1126/...

25.09.2025 18:03 πŸ‘ 66 πŸ” 33 πŸ’¬ 1 πŸ“Œ 1
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Just because it is so beautiful. Megachile laechella. Rare in the Netherlands, but locally abundant in the dunes of Terschelling. The Dutch name 'zilveren fluitje' means silver whistle, after the high tone it makes while flying and the colour of.., well just look at it.

21.06.2025 12:07 πŸ‘ 3 πŸ” 1 πŸ’¬ 0 πŸ“Œ 0

Yes, we want to know at what distance plant populations become reproductively isolated. And whether, restoring patches of wildflowers reduces isolation or actually worsens it (pollen competition). Both are possible.

21.06.2025 09:28 πŸ‘ 1 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0
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They seem to be a lot less shy on Terschelling (NL). Took this one yesterday with my phone.

19.06.2025 17:28 πŸ‘ 5 πŸ” 3 πŸ’¬ 1 πŸ“Œ 0
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Bees and beers. The typical use of fridges by pollinator ecologists during field season.

23.05.2025 16:38 πŸ‘ 6 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0
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In another project restpoll.bsky.social we investigate whether flower plantings can improve pollen dispersal between subpopulations. Scientists in action.

23.05.2025 16:35 πŸ‘ 4 πŸ” 1 πŸ’¬ 1 πŸ“Œ 0
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What are the consequences of pollinator decline for wild plants? Here we try to find out in @valor-project.eu. Interesting observations. I never see Centaurea jacea flowers with pollen. But keep the pollinators away and the flowers are dusted white. Very popular species.

23.05.2025 16:26 πŸ‘ 9 πŸ” 2 πŸ’¬ 0 πŸ“Œ 0

Excited to be presenting results from the SHOWCASE project and Agroforestry Group this month!

Our farm trials across England have shown cover crops can increase earthworms by 65% in the following cash crops! AND agroforestry promotes worms too, especially in drought years 😎

Hope to see you there!🌾

09.05.2025 15:56 πŸ‘ 8 πŸ” 2 πŸ’¬ 0 πŸ“Œ 0
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Managing water for waders Your task, should you choose to accept it, is to turn farmland into a haven for breeding waders. The only tools you have at your disposal are tractors and cows and we will give you permission to pu…

... (reserve-equivalent) enhancement initiatives, supported by one-to-one advice, within or close to existing reserves."
Here's an example of this working for waders in eastern England, spear-headed by the much-missed Mark Smart:
wadertales.wordpress.com/2019/06/14/m...
#ConservationScience🌍

21.04.2025 06:08 πŸ‘ 13 πŸ” 5 πŸ’¬ 0 πŸ“Œ 0
A brick residential street in Delft lined with trees, benches, bike parking, and low-rise brick and wooden buildings. The first storey of many of these buildings is covered with climbing plants and flowers.

A brick residential street in Delft lined with trees, benches, bike parking, and low-rise brick and wooden buildings. The first storey of many of these buildings is covered with climbing plants and flowers.

A brick residential street in Delft lined with trees, benches, bike parking, and low-rise brick and wooden buildings. The first storey of many of these buildings is covered with climbing plants and flowers.

A brick residential street in Delft lined with trees, benches, bike parking, and low-rise brick and wooden buildings. The first storey of many of these buildings is covered with climbing plants and flowers.

A brick residential street in Delft lined with trees, benches, bike parking, and low-rise brick and wooden buildings. The first storey of many of these buildings is covered with climbing plants and flowers.

A brick residential street in Delft lined with trees, benches, bike parking, and low-rise brick and wooden buildings. The first storey of many of these buildings is covered with climbing plants and flowers.

A brick residential street in Delft lined with trees, benches, bike parking, and low-rise brick and wooden buildings. The first storey of many of these buildings is covered with climbing plants and flowers.

A brick residential street in Delft lined with trees, benches, bike parking, and low-rise brick and wooden buildings. The first storey of many of these buildings is covered with climbing plants and flowers.

The geveltuin (β€œfacade garden”) policy is found in most Dutch municipalities, as here in Delft. Provided they meet a set of requirements, including preserving footpath width, residents are encouraged to remove paving stones in front of their property and replace them with greenery. No permit needed.

20.04.2025 15:13 πŸ‘ 297 πŸ” 73 πŸ’¬ 7 πŸ“Œ 9