Cold waves in the Amazon rainforest and their ecological impact

Cold waves crossing the Amazon rainforest are a rare phenomenon predicted to increase in intensity under climate change. We here describe an extensive cold wave occurring in June 2023 in Amazonian-Andean forests, compared environmental temperatures to experimentally tested thermal tolerances and its impact on lowland animal communities (insects and wild mammals). While we found strong reductions in abundance of all animal groups under the cold wave, tropical lowland animals showed thermal tolerance limits below the lowest environmental temperatures measured during the cold wave, and abundances of most studied taxa recovered over the next season; nevertheless, small thermal safety margins suggest that an increased intensity of cold waves in the future could imperil animal communities in the Amazon., Temperature data
Air temperature was measured at each plot along the elevation gradient with iButton sensors (Analog Devices, Inc, Wilmington, USA) at 1.5 m height every four hours, hanging from a horizontal branch. The sensors were shielded with white plastic dishes (diameter ca. 18 cm) to protect them from rain and direct sunlight [13]. In addition, each plot was equipped with a TOMST4-temperature and soil humidity logger (TOMST s.r.o., Prague, Czech Republic), continuously measuring temperature and soil humidity at 6 cm depth, as well as temperature at the surface and in 15 cm height.
Insect data
(1) Malaise: At each plot in each field season, one malaise trap was operated for seven days. Malaise traps were based on the Townes Malaise trap model, albeit with a black roof and a slightly smaller size (dimensions of the capture area: height front: 0.90 m; height rear: 0.60 m; length: 1.60 m); Ethanol (96 %) was used as the capture fluid to ensure the preservation of specimens. For each ..., , # Cold waves in the Amazon rainforest and their ecological impact

[https://doi.org/10.5061/dryad.ns1rn8q31](https://doi.org/10.5061/dryad.ns1rn8q31)

## Description of the data and file structure

Climate and biodiversity were monitored at three study locations (\"plots\") in the Peruvian rainforest. We used thermal sensors, pitfall traps, malaise traps, manual netting and camera traps. Thermal tolerance experiments were conducted with a programmable thermoblock.

### Files and variables

#### File: Malaise.xlsx

**Description:** Malaise traps for community biomass of mainly flying insects

##### Variables

* Plot: ID of study site
* Field_season: number of sampling round 
* dateon: Date of setting up the trap
* dateout: Date of removing the trap
* Note: special observations
* Mass: wet insect biomass in gram

#### File: dailyTemp\_iB.xlsx

**Description:** temperature measured by iButton loggers

##### Variables

* Tmean: daily mean temperature

- Tmin: daily minimum temperature
- Tmax:...