Invertebrate diversity in groundwater filled lava caves is influenced by both neutral and niche-based processes

Aim: Understanding which factors shape and maintain biodiversity is essential to understand how ecosystems respond to crises. Biodiversity in ecological communities is a result of the interaction of various factors which can be classified as neutral or niche-based. The importance of these processes has been debated, but many scientists believe that both processes are important. Here we examined the importance of neutral vs. niche-based factors for shaping invertebrate communities. We hypothesized that if neutral processes are the main drivers of community structure we would not see any clear relationship between the structure of community and ecological factors. If niche-based processes are important we should see clear relationships between community structure and variation in ecological variables.
Location: Groundwater-filled lava caves near Lake Mývatn, Iceland.
Methods: We collected various ecological variables from these caves. Invertebrate communities were collected on the hard bo..., The following environmental variables in the caves were measured in June and August from 2013 – 2019: temperature (°C), oxygen saturation (%), pH, and specific conductivity (µS/cm), using a multiprobe sonde (Hydrolab DS5 (46711) Water Quality Probes). From a digital map we estimated the minimal distance of each cave from the lake (in meters) and key physical characteristics of the caves, such as the combined vertical area of all openings and the size of the cave pond exposed to air (both in m2), in some caves the roof was overhanging, so the pond exposed to air value was negative. Based on this, we estimated the area available for photosynthesis by adding half the vertical area of openings to the size of the cave pond exposed to air. In each cave, we placed fall-in traps within 20 cm of the shore to collect external inputs into the pond. The main objective of the traps was to estimate food availability for Arctic charr for another study. The traps were built of clear buckets (Unipak mod..., , # Cave invertebrates and environment - 2014

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

Here is data from research on freshwater invertebrates from benthic and epibenthic samples, and ecological measurements. These samples originate in freshwater ponds in lava caves around lake Mývatn SE Iceland. In total 18 caves were sampled, but the number differ though between the benthic and epibenthic samples

## Description of the data and file structure

We have uploaded the following files:

Env2. csv - Here is the environmental data across the different caves. Cave is the identifier of the cave. Area is the area the cave is located, there are two areas Haganes (H) and Vindbelgur (V). Temp, is temperature in °C, pH is a measure of pH, Cond, is a measure of conductivity in microsimens, Oxygen, is oxygen % of the water, Photosynthesis is an indicator of area available for photosynthesis, Distance, is the distance of the cave from Lake Mývatn, organic mat...