DOI: 10.6084/m9.figshare.10193594.v1
title: Determinants of intra-annual population dynamics in a tropical soil arthropod

description: This dataset consists of spatiotemporal data on counts of the soil mite Rostrozetes ovulum (Oribatida: Haplozetidae) in central Amazonia, along with data on climate and litterfall variables used to model the mite's population dynamics.<br>We sampled the mite in 20 transects a 800-ha forest remnant in Manaus, northern Brazil (03°04’34”S; 59°57’30”W). Each transect was 20-m long. Transects were distributed all over the forest landscape and sampled from June 2014 to June 2015. Ten transects were in valleys, while the remaining transects were located on plateaus, at least 150 m away from any drainage catchment. At each transect, one soil sample was taken each meter using an aluminum soil corer (3.5 × 3.5 × 5 cm), covering a total of 245 cm2. This material was taken to the laboratory, where the soil fauna was extracted using a Berlese-Tullgren apparatus (Franklin & Morais 2006). Each soil core was put in a sieve with mesh size 1.5 mm, which was placed in a plastic funnel. Then, the funnel was put into a wooden box, where it was fitted through a perforated polystyrene board, with a glass vial filled with 95 percent alcohol below it. Next, the box was gradually heated from ambient temperature (ca. 27ºC) to 35 – 40 ºC using light bulbs (25 W). Vials were checked daily for fallen animals. Heating lasted until the core was completely dry and animals stopped falling into the vial (7 to 10 days). The collected material was surveyed under a stereomicroscope for R. ovulum. Adult individuals were counted and preserved in 95 percent alcohol. Transects were sampled on nine months (June to September and November 2014; and January, March, April and June 2015). Therefore, the spatiotemporal coverage of our study was 20 transects × 13 months = 240 spatiotemporal units, of which 20 transects × 9 surveys = 180 counts were recorded from a total of 3600 soil cores.<br>Environmental seasonality data were obtained from research sites nearby the study area, or estimated from such sites. Temperature and rainfall data were gathered online from the nearest station of the Brazilian Institute for Meteorology (INMET), which is 1 km from the study area. We extracted daily readings to compute cumulative rainfall (mm) and maximum daily air temperature (°C) for each transect and month covered by our sampling.<br>Litterfall was estimated using time series of monthly litter production per habitat (plateau and valley) from the Cuieiras Biological Reserve (22,735-ha), 60 km from the study area. Litterfall was sampled with 30 PVC collectors (50 × 50 cm) randomly placed 50 cm above ground in each habitat, between May 2004 and December 2005, January 2009 and December 2010, and November 2014 and August 2015. In parallel, we obtained meteorological data from the INMET station corresponding to the litterfall measurements to model the latter as a function of (1) monthly sunlight hours, monthly cumulative rainfall and their interaction, (2) habitat (valley or plateau), and (3) time (months, coded as integers spanning the temporal coverage of the data) in order to account for any long-term trend. The model was the used to predict the expected litterfall for each spatiotemporal unit in which the mite was sampled, given the corresponding environmental conditions.<br>