Fencing the flux: Seasonal trends, environmental drivers, and mitigation opportunities of methane emissions from farm dams

Farm dams are significant methane (CH4) sources in agricultural landscapes. Fencing them to limit livestock access reduces organic matter and nutrient inputs, thereby limiting CH4 production. However, existing studies on the benefits of fencing are constrained by short durations, omission of ebullitive fluxes, limited spatial and temporal coverage, and small sample sizes. Here, we report a large-scale, multi-season assessment of total CH4 (diffusive + ebullitive) and carbon dioxide (CO2) fluxes from fenced and unfenced farm dams, along key environmental drivers. We monitored 113 farm dams in temperate mainland south-eastern Australia over two years, amounting to 39,552 and 45,408 hourly observations of total CH4 and CO2 fluxes, respectively. We integrated field-measured emissions with Sentinel-2 indices, topo-climate variables, and geostatistical models to identify flux drivers, quantify temperature sensitivity, and spatially extrapolate mitigation potential across Local Government Auth..., This research was conducted in temperate mainland south-eastern Australia (Fig. 1), covering the states of Victoria, New South Wales, and southern Queensland. The region spans approximately from –39.14° to –25.85° latitude and from 140.96° to 168.00° longitude, encompassing temperate zones across these states with diverse landscapes, including temperate grasslands, coastal plains, and montane environments, and has a temperate climate influenced by the Southern Ocean. Seasonal temperatures range from 25–30°C in summer (December–February), 20–25°C in autumn (March–May), 15–25°C in spring (September–November), and 6–10°C in winter (June–August). Annual rainfall, peaking in winter, typically varies from 400 to 1200 mm. Livestock grazing, particularly beef cattle and sheep, dominates the region’s agriculture. The study area spans 526,296 km2 and contains an estimated 249,305 farm dams, with an average total water surface area of about 24,000 hectares (ha) across 168 Local Government Authorit..., # Fencing the flux: Seasonal trends, environmental drivers, and mitigation opportunities of methane emissions from farm dams

### Running title: **Fencing Farm Dams to Cut Methane Fluxes**

#### 1. Overview

This dataset (Odebiri_et_al_2025_Global_Change_Biology.zip) accompanies the article *“Fencing the Flux: Seasonal Trends, Environmental Drivers, and Mitigation Opportunities of Methane Emissions from Farm Dams”* published in *Global Change Biology* (Odebiri et al., 2025). The dataset provides the empirical and processed data used to quantify methane (CH₄) and carbon dioxide (CO₂) emissions from farm dams across temperate Southeastern Australia (2022–2024). It includes raw flux data, Sentinel-2 and terrain predictors, climate data, shapefiles, and analysis scripts used to assess seasonal patterns, environmental drivers, and emission mitigation potential via fencing interventions.

#### 2. Contents of the Dataset

| File/Folder | Description ...,