Multi-year water level drawdown and wildlife grazing drive wetland vegetation succession

In wetlands, multi-annual water level drawdowns and herbivory can induce cyclic vegetation succession. While water level drawdowns can be used in wetland management to increase the area of reed vegetation, an important habitat for wetland birds, herbivory may interfere with this process. Here, we studied the combined effects of a human-induced water level drawdown, i.e. the intentional temporarily and large scale lowering of the water level, and herbivores on wetland vegetation development.
In the Oostvaardersplassen wetland, we used satellite imagery to assess vegetation development with and without water level drawdown and with and without red deer presence (introduced in 1992). An herbivore exclosure experiment (2022-2024) across an elevational gradient tested the effect of grazing on vegetation development during a drawdown.
Satellite imagery showed an expansion of reed cover by 560 ha in the period without red deer (1987-1991) and by 420 ha with red deer (2020-2024), only in the ar..., Study Site
The Oostvaardersplassen is a eutrophic wetland in the Netherlands (52°27'N 5°19'E) (Figure 1A). It is in a former part of the Zuiderzee estuary, which was closed off from the North Sea in 1932 and gradually turned into a freshwater lake due to input from the river IJssel (Van Leeuwen et al., 2021). In 1968, land was reclaimed, mainly for agriculture purposes. The lowest and wettest part of the polder (around 5600 ha), destined for industrial activities, was left unmanaged during the first years after reclamation. This part developed into a marsh and attracted many rare and characteristic wetland bird species. This natural development prompted a shift in management strategy, leading to its designation as a protected nature reserve (Cornelissen et al., 2014; Jans and Drost, 1995). The reserve consists of a reed-dominated marsh (c. 3600 ha) and a border zone with wet and dry grasslands (c. 2000 ha). In this paper, we focussed on the reed-dominated marsh of the reserve (Figure 1B..., # Data from: Multi-year water level drawdown and wildlife grazing drive wetland vegetation succession

Dataset DOI: [10.5061/dryad.rxwdbrvpp](https://doi.org/10.5061/dryad.rxwdbrvpp)

## Description of the data and file structure

We constructed 27 exclosures (paired with a control plot) across the Oostvaardersplassen. The exclosures are placed in 9 rows of each 3 exclosures across an elevational gradient (high, intermediate, low). Within the exclosures we monitored vegetation composition, height, water depth and sediment elevation. \
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Additionally, we monitored vegetation across the area without exclosures and used this to train a model to classify satellite images (supplemented with locations that were assessed by experts to assign a vegetationtype). 

Lastly, we provide data on red deer and geese presence assessed through cameratrap images. 

### Files and variables

#### File: Data-Bouma_et_al.*2025*-_Ecological_Engineering.zip

**Description:** 

There are three maps within this z...,