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Increased microclimatic variation in artificial nests does not create ecological traps for a secondary cavity breeder, the European roller

Citation

Schwartz, Timothée; Genouville, Arnaud; Besnard, Aurélien (2021), Increased microclimatic variation in artificial nests does not create ecological traps for a secondary cavity breeder, the European roller, Dryad, Dataset, https://doi.org/10.5061/dryad.xksn02vdg

Abstract

Artificial devices are increasingly used in conservation measures to mitigate the disappearance of natural habitats. However, few studies have demonstrated their benefits for the target species, and they may pose a risk of creating ecological traps. This occurs when lower individual fitness is found in artificial habitats that are more attractive than their natural equivalents. In this study, we tested the ecological trap hypothesis on a dense population of European rollers Coracias garrulus breeding in both natural cavities and nest-boxes. Our initial prediction was that the more stressful microclimatic conditions of nest-boxes would lead to reduced fitness of European rollers, thus creating an ecological trap. The results showed that nest-boxes were preferred over natural cavities. Despite significantly more extreme microclimatic conditions in nest-boxes, we found similar breeding parameters between artificial and natural nest types. Our results also suggest that European rollers selected the nest-boxes which best buffered the temperature, thus avoiding potential ecological traps. Overall our results led to the conclusion that nest-boxes do not create ecological traps for European rollers in this study area. However, other species may be more sensitive to microclimatic variations or less able to avoid the least favourable nest-boxes. These findings could help to inform the placement of nest-boxes in order to reduce extreme temperatures and variation in humidity rates. Future studies could compare nest types for other fitness parameters, such as juvenile body condition or survival. We also recommend the ecological trap hypothesis as a useful framework to evaluate the outcomes of artificial devices used for conservation.

Methods

See paper (open access)

Usage Notes

Meaning of each column:

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alldata_microclimate_15days.csv

Name of the column Description
Daily microclimate variables
MaxTint Maximal temperature in the nest (°C)
MinTint Minimal temperature in the nest (°C)
MoyTint Mean temperature in the nest (°C)
DiffTint Difference between maximal and minimal temperature in the nest (°C)
Dtmoyabs Mean over a day of the absolute delta between interior and exterior temperature (°C)
Dtmaxabs Absolute value of the daily maximum delta between interior and exterior temperature (°C)
Maxhum Maximum humidity level in the nest (%RH)
Minhum Minimum humidity level in the nest (%RH)
Moyhum Mean humidity level in the nest (%RH)
DiffHum Difference between maximal and minimal humidity level in the nest (%RH)
 
Name Name of the nest-box or cavity
Type Nest type : either nest-box or cavity
occupation Occupation of the nest by rollers during the breeding season : 1 for roller nests, 0 otherwise
OccR Real occupation of the nest during monitoring (roller or starling) : 1 for occupied nests sensor measurements, 0 for empty nests during sensor measurements
Developmental stage Number of days between the day of measurement and the first egg-laying date (0 for nests not occupied by rollers)
First egg-laying date Day of the laying of the first egg (for roller nests only) (Julian calendar date)
CH Cavity height (m)
CBH Circumference of the tree at breast height (1.30m) (cm) (natural cavities only)
CCH Circumference of the tree at cavity height (cm) (natural cavities only)
Orientation Entrance orientation of the nest (degrees)
Ori Simplified orientation of the nest (either N, E, S or W with N: 316°-45°; E: 46°-135°; S: 136°-225°; W: 226°-315°)
EH Entrance height (cavity) (mm) (natural cavities only)
EW Entrance width (cavity) (mm) (natural cavities only)
CL Cavity length (cm) (vertical) : minimum distance from the bottom of entrance hole to the bottom of the chamber (natural cavities only)
CD Cavity depth (cm) (horizontal) : minimum distance from the entrance hole to the back wall of the cavity (natural cavities only)
Date Day of the measurement (Julian calendar date)

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reproduction_data_2016-2019.csv

Name of the column Description
Name Name of the nest-box or cavity
Type Nest type : either nest-box or cavity
year Year of monitoring of the nest
eggs Size of the clutch (complete clutches only)
chicks Number of hatched eggs in complete clutches
fledglings Number of fledglings
success 1 if at least 1 fledgling, 0 otherwise
n_failed_eggs Number of eggs that did not produce a fledgling

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average_microclimate_&_characteristics_NB_CAV.csv

Name of the column Description
Mean microclimate variables over 15 consecutive days
MAXTint Maximal temperature in the nest (°C)
MINTint Minimal temperature in the nest (°C)
MOYTint Mean temperature in the nest (°C)
DIFFTint Difference between maximal and minimal temperature in the nest (°C)
DTMOYabs Mean over a day of the absolute delta between interior and exterior temperature (°C)
DTMAXabs Absolute value of the daily maximum delta between interior and exterior temperature (°C)
MAXHum Maximum humidity level in the nest (%RH)
MINHum Minimum humidity level in the nest (%RH)
MOYHum Mean humidity level in the nest (%RH)
DIFFHum Difference between maximal and minimal humidity level in the nest (%RH)
 
Name Name of the nest-box or cavity
Type Nest type : either nest-box or cavity
occupation Occupation of the nest by rollers during the breeding season : 1 for roller nests, 0 otherwise
OccR Real occupation of the nest during monitoring (roller or starling) : 1 for occupied nests sensor measurements, 0 for empty nests during sensor measurements
CH Cavity height (m)
CBH Circumference of the tree at breast height (1.30m) (cm) (natural cavities only)
CCH Circumference of the tree at cavity height (cm) (natural cavities only)
Orientation Entrance orientation of the nest (degrees)
Ori Simplified orientation of the nest (either N, E, S or W with N: 316°-45°; E: 46°-135°; S: 136°-225°; W: 226°-315°)
EH Entrance height (cavity) (mm) (natural cavities only)
EW Entrance width (cavity) (mm) (natural cavities only)
CL Cavity length (cm) (vertical) : minimum distance from the bottom of entrance hole to the bottom of the chamber (natural cavities only)
CD Cavity depth (cm) (horizontal) : minimum distance from the entrance hole to the back wall of the cavity (natural cavities only)