DOI: 10.5061/dryad.ttdz08m70
title: Nest site selection and nesting behavior of Reeves’ turtle (Mauremys reevesii) in Qichun County, Hubei Province, China

description: Research on nest site selection and nesting behavior is essential for
 species conservation. Research on the reproductive ecology of Reeves'
 turtles is relatively scarce. Therefore, from April to September 2022, we
 conducted a study in Qichun County, China, on the field nest site
 selection of 11 female Reeves' turtles using tracking line boxes. We
 also investigated the nesting behavior of 20 female turtles using
 high-definition surveillance cameras placed within an enclosure and
 recorded the clutch size. The results showed that slope, canopy cover, and
 distance from the water source significantly influenced nest site
 selection. Canopy cover significantly differentiated selected quadrats
 from random quadrats and the distance from the water source affected nest
 predation risk. The nesting behavior was divided into five stages:
 landing, excavation, egg laying, covering, and return, with a nesting
 season from early May to the end of July and nesting most occurring during
 dusk and dawn. The average clutch size was 7.33 ± 0.33 eggs. Reproduction
 was affected by high nest predation rates and extreme weather conditions.
 This study provides valuable information on this endangered species and a
 foundation for the development of conservation plans.
description: <em>Nest site selection</em> This
 study was conducted in Qichun County, Hubei Province, China (29°59′–30°40′
 N, 115°12′–115°56′ E), from April to August 2022. We captured 11gravid
 female wild Reeves' turtles (using a portable X-ray machine to scan
 the turtles' lower abdomen to confirm the presence of hard-shelled
 eggs ) using cage traps , which were dismantled after capture to avoid
 harm to local wildlife. Then, a tracking line box was attached to the rear
 of the turtle's carapace. A fishing line was wound around the pulley
 to a length of approximately 70 m. The total weight of the tracking line
 box and adhesive did not exceed 40 g. Because the experimental turtles
 were large (≥ 400 g), the tracking line boxes did not affect their normal
 movement. The experimental Reeves' turtles were then released where
 they were captured. To prevent the fishing line from running out and
 affecting the turtle's normal activity, the specific locations of the
 turtle were determined at 06:00, 14:00, and 20:00 and the fishing line was
 reeled in. Signs of nest construction were checked along their path to
 identify the nests. After the experiment was completed, all tracking line
 boxes were carefully removed and the experimental turtles were released
 into the aquatic habitats nearest to their nesting sites.
 After locating a nest site, two quadrats of different sizes
 centered on the nest were established. In the small quadrat (1 × 1 m), we
 quantified soil hardness, leaf litter thickness, shrub and herb cover, and
 height. In the large quadrat (5 × 5 m), we quantified the slope, slope
 position, slope direction, distance from human disturbance, canopy cover,
 vegetation type, distance from the water source, and height above the
 water source. <em>Nest characteristics, clutch
 size, and egg characteristics</em> After locating
 the nest, the eggs were gently excavated while minimizing damage to the
 nest structure. The side of the egg with the fertilization spot facing
 upward was placed and the nest depth, inner width, entrance diameter, egg
 length, and egg width were measured using Vernier calipers. Egg weight was
 measured using an electronic balance and the number of eggs in the clutch
 was recorded. After measurements were taken, the eggs were placed back
 into the nest and the nest was restored to its original
 condition. <em>Nesting
 behavior</em> At the study site, we constructed a
 15-m<sup>2</sup> enclosure simulating a natural habitat.
 Surveillance cameras and temperature loggers were installed in the
 enclosure. We introduced 20 sexually mature wild female Reeves'
 turtles captured using cage traps into the enclosure. To cover the entire
 nesting season, the monitoring system was turned on for 24-h recording
 from May 25th to September 1st. During the experiment, a video from the
 monitoring system was downloaded and watched daily to observe nesting
 behavior. Data such as the time of occurrence, total duration, duration of
 each behavioral phase, and weather were recorded. After completion of the
 experiment, all experimental turtles were released into several aquatic
 habitats where we had previously captured individuals of this
 species. <em>Statistical
 analysis</em> All statistical analyses were
 conducted using SPSS 19.0 (SPSS Inc., Chicago, IL, USA). For quantitative
 data in the study of nest site selection, the normality of the data was
 assessed using the Kolmogorov-Smirnov test before further analysis.
 Paired-sample t-tests were used to analyze significant differences in
 ecological factors between the selected and random quadrats if the data
 were normally distributed and had homogeneous variances. Descriptive
 statistics were reported as mean ± standard error (SE). If the data were
 not normally distributed, the Wilcoxon signed-rank test was used and the
 results are presented as medians (minimum, maximum). For qualitative data,
 significant differences were determined using the chi-squared test after
 calculating the frequency distribution. Discriminant function analysis was
 used to identify the ecological factors that could most significantly
 differentiate between the selected and random quadrats, as well as the
 main factors affecting nest predation. For studies that did not require
 hypothesis testing, descriptive statistics were presented as mean ± SE.
 The significance level was set at <em>p</em> &lt;
 0.05.
description: # Nest site selection and nesting behavior of Reeves turtle (Mauremys
 reevesii) in Qichun County, Hubei Province, China
 [https://doi.org/10.5061/dryad.ttdz08m70](https://doi.org/10.5061/dryad.ttdz08m70) ## Description of the data and file structure The dataset contained in the file titled "raw data.xlsx" appears to support a study on the nesting behavior and site selection of Reeves' turtle (*Mauremys reevesii*) in Qichun County, Hubei Province, China. The following points summarize the dataset in relation to the experimental procedures and results described in the study: 1. Nest Site Selection: Variables Recorded: The dataset likely includes variables related to environmental and physical characteristics of the nest sites chosen by the turtles, such as soil type, vegetation cover, temperature, and proximity to water sources. Procedure: The selection of nest sites by turtles was likely observed and documented over a specified period, with the researchers recording relevant environmental variables at each site. Results Context: The study would have analyzed how these environmental factors influence nest site selection, determining which characteristics are most strongly preferred by the turtles. 2\. Ecological survey tracking of 11 Reeves' turtles in the wild Variables Recorded: Morphological and physiological indicators of the 11 individual turtles tracked in the experiment, including carapace length, carapace width, plastron length, plastron width, weight, egg-laying date, clutch size, and the fate of the nests (whether they were predated). Procedure: Before conducting the tracking experiment, the measurements of the experimental individuals were taken. After the experiment concluded, the egg-laying date, clutch size, and whether the nests were predated were recorded for each individual. Results Context: These data allow researchers to analyze the nesting season and peak nesting periods of Reeves' turtles and help to understand the reproductive capacity and nest predation rate of Reeves' turtles in the study area. 3\. Nest Data Variables Recorded: Basic data of all undisturbed nests found during the experiment, including location (field/enclosure), nest depth, nest inner width, opening diameter, success or failure, egg weight, egg length, and egg width. Procedure: Undisturbed nests were discovered through both tracking and enclosure methods, and their basic characteristics and egg traits were recorded. Results Context: These data allow researchers to analyze the reproductive success rate, nest characteristics, and egg traits of Reeves' turtles in the study area. 4\. Nesting Behavior Variables Recorded: The date of nesting behavior, start time, duration, time spent in each phase, and weather conditions were recorded. Procedure: Data were recorded by repeatedly reviewing surveillance footage. Results Context: These data allow researchers to analyze the nesting season, peak nesting periods, and the steps of the nesting process of Reeves' turtles. 5\. Breeding Season Temperature Variables Recorded: The daily maximum and minimum temperatures during the entire breeding season were recorded. Procedure: Data were obtained using a temperature logger placed within the enclosure. Results Context: This helps researchers analyze the triggers for Reeves' turtle breeding behavior and the causes of breeding failure. **Sharing/Access information** How to use this dataset For quantitative data in the study of nest site selection, the normality of the data was assessed using the Kolmogorov-Smirnov test before further analysis. Paired-sample t-tests were used to analyze significant differences in ecological factors between the selected and random quadrats if the data were normally distributed and had homogeneous variances. Descriptive statistics were reported as mean ± standard error (SE). If the data were not normally distributed, the Wilcoxon signed-rank test was used and the results are presented as medians (minimum, maximum). For qualitative data, significant differences were determined using the chi-squared test after calculating the frequency distribution. Discriminant function analysis was used to identify the ecological factors that could most significantly differentiate between the selected and random quadrats, as well as the main factors affecting nest predation. For studies that did not require hypothesis testing, descriptive statistics were presented as mean ± SE. The significance level was set at p &lt; 0.05. **Code/Software** All statistical analyses were conducted using SPSS 19.0 (SPSS Inc., Chicago, IL, USA).