DOI: 10.5061/dryad.h70rxwdw6
title: Data from: Territory size but not territorial defence varies with habitat quality and competitor density in a farming species

description: High-quality habitats are predicted to have higher densities of
 competitors, smaller territory sizes, and increased defensive costs for
 territory holders. However, defence is typically considered to be directed
 predominantly towards conspecifics, with heterospecific intrusions
 generally thought to contribute less towards defensive costs. Moreover,
 individuals may benefit from the collective defence of resources in areas
 with increased densities of territory holders. Together, these factors
 could affect the costs of defence in low- versus high-quality habitats. In
 this study, we investigated how habitat quality and conspecific density
 influence the territorial defence of algal-farming yellowtail damselfish
 (Stegastes arcifrons) in the Galapagos. We quantified territory
 characteristics, performed behavioral observations, and conducted an in
 situ experiment to test whether damselfish in higher quality, conspecific
 damselfish dense habitats (characterized by increased algal turf
 coverage), differ in their competitive intrusion frequencies and defensive
 costs of chasing compared to those in lower quality areas. We found that
 damselfish in poorer quality habitats with fewer conspecific neighbours,
 had larger territories compared to those in higher quality, more
 damselfish dense areas. Despite this, both high- and low-quality territory
 holders experienced equivalent numbers of competitive intrusions. However,
 the type of competitor varied: territory holders in high-quality areas
 primarily defended against conspecifics, while those in lower-quality
 areas faced more frequent heterospecific intrusions. We also found no
 evidence that damselfish in high-quality habitats gained any collective
 benefits of defence by having increased densities of conspecific
 damselfish nearby. Thus, while higher conspecific density in higher
 quality habitats might alter the risk from certain intruders, it does not
 appear to confer direct collective defence benefits in terms of reducing
 defence effort once intruded upon. Instead, territory holders appear to
 adapt their defence to balance the defensive pressures posed by
 conspecifics and heterospecifics, maintaining similar overall defensive
 costs across differing habitat qualities.
description: # Data from: Territory size but not territorial defence varies with
 habitat quality and competitor density in a farming species Dataset DOI:
 [10.5061/dryad.h70rxwdw6](10.5061/dryad.h70rxwdw6) ## Description of the
 data and file structure These data were used to investigate how habitat
 quality and damselfish density jointly influence the territorial defense
 strategies of yellowtail damselfish (*Stegastes arcifrons*) in the
 Galapagos.  ### Files and variables #### File:
 RCODE_Territory_size_but_not_territorial_defence_varies_with_habitat_quality_and_competitor_density_in_a_farming_species.Rmd **Description:** R Notebook file used to analyze data and create figures.  #### File: DATA_Territory_size_but_not_territorial_defence_varies_with_habitat_quality_and_competitor_density_in_a_farming_species.xlsx **Description:** Individual csv files are included in this Excel file as individual tabs. Each tab is named, and these names are referred to in the accompanying R Script where data is loaded. ##### Variables **Sheet: Data_damsel_quadrat_mean.csv** | Column | Description | | ---------- | ---------------------------------------------------------------------------- | | Quality | Categorical habitat quality for each territory (low or high) | | Mean\_turf | Mean % amount of algae within quadrat (mean calculated across three scorers) | | Mean\_sand | Mean % amount of sand within quadrat (mean calculated across three scorers) | **Sheet: Data_damsel_territory.csv** | Column | Description | | ---------------------- | -------------------------------------------------------------------------------------------- | | ObsID | Individual ID assigned to each observation | | Quality | Categorical habitat quality for each territory (low or high) | | Size\_longest.distance | Longest length of territory to nearest 5 cm | | X70\_NumberNeigh | Number of conspecifics adults within 70 cm radius of objects placement position in territory | | Depth | Measured water depth (cm) above territory | **Sheet: Data_damsel_behaviour.csv** | Column | Description | | ------------ | ---------------------------------------------------------------------------- | | ObsID | Individual ID assigned to each observation | | Density | Categorical damselfish density for each territory (low or high) | | Intrusions | Total number of intrusions into territory (includes unidentified intrusions) | | Chases | Total number of chases towards intruders | | Pecks | Total number of substrate pecks by focal | | Con\_intrude | Number of intrusions by adult conspecifics | | Con\_chase | Number of chases towards juvenile conspecifics | | Het\_intrude | Number of intrusions by heterospecifics | | Het\_chase | Number of chases towards heterospecifics | **Sheet: Data_damsel_manipulation.csv** | Column | Description | | ----------------------------------------------- | ----------------------------------------------------------------------------------- | | ObsID | Individual ID assigned to each observation | | Density | Categorical damselfish density for each territory (low or high) | | Manipulation | Each damselfish was presented with either an urchin or tennis ball (control) object | | Number\_attacks\_in\_territory\_focal | Number attacks on object by focal fish while within territory | | Number\_attacks\_by\_conspecific\_in\_territory | Number attacks on object by conspecific adults while within territory | | Time\_first\_attack | Time in seconds to first attack of object (NA indicates no attack) | | Object\_position | Whether object was in or out of focal's territory at end of trial | | Total\_time\_object\_in | Total time in seconds that object was in focal's territory | | Object\_back\_in | Whether object was moved back in (1) or not (0) to focal | **Sheet: Data_Sampling.csv** | Column | Description | | ------------ | ----------------------------------------------------------------------------------------- | | Date | Sampling date | | Time | Sampling time of day | | Type | Sampling method: quadrat versus behavioural observation | | Area | Reef area: high quality high damselfish density versus low quality low damselfish density | | Manipulation | Collection type: quadrat, behavioural observation (tennis or urchin presentation | **Sheet: Data_tide.csv** | Column | Description | | ---------------- | ------------------------------------- | | Date | Sampling date | | TimeDay | Time of high or low tide | | TideHeight | Water depth of high or low tide (m) | | High\_Low\_Water | Categorical water depth (low or high) | ## Code/software Data can be read directly into R using the "read_excel" call from the "officer" package. The included R Notebook file calls each data file tab directly and reproduces figures and results tables.  ## Access information Other publicly accessible locations of the data: * NA Data was derived from the following sources: * No - data were collected in situ.