Data from: Fish responses to manipulated microhabitat complexity in urbanised shorelines
Data files
Mar 18, 2024 version files 117.03 KB
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day_diversity.csv
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microhabitat_func_composition.csv
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microhabitat_taxo_composition.csv
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night_diversity.csv
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README.md
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size-matching_relationship.csv
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structure_func_composition.csv
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structure_taxo_composition.csv
Abstract
The diversity-habitat complexity relationship has been utilised widely in conservation and biodiversity enhancement interventions, but few studies have attempted to tease apart the components of complexity that drive this relationship. The ecological engineering of seawalls is one area where this topic has advanced, albeit not at scales relevant to fish. We constructed habitat enhancement units (Simple, Complex, and Freestyle ‘fish houses’) out of hollow concrete blocks and installed them at the base of tropical rip-rap seawalls. Both the Simple and Complex fish houses were cuboid, had the same surface area and volume, and included 100 holes (microhabitats). The holes in Simple fish houses were all the same size, whereas 25 size variations were used in the Complex design (volume-independent manipulation of a single complexity element). The Freestyle fish house was non-cuboid and had more overall volume, microhabitat types and sizes. We examined the volume-independent (Simple vs Complex fish houses) and volume-dependent (Freestyle fish house) effects of microhabitat complexity on fish taxonomic and functional assemblage metrics at two spatial scales and across diel cycles We also investigated diurnal and nocturnal fish-microhabitat size relationships. There was a modest, but not significant, volume-independent effect of complexity on fish assemblages. The Freestyle design supported significantly greater abundance, species richness and distinct taxonomic and functional compositions. These results were dependent on spatial scales and diel cycles. Diel variation in fish activity patterns resulted in stronger size-matching relationships between fish and microhabitat at night than day. Synthesis and applications. Our study shows that, to enhance fish diversity, it is important to provide three-dimensional habitat architecture that incorporates a wide range of microhabitat sizes and types. Our findings also highlight some key considerations when assessing the performance of intervention designs, including spatial-scale dependent effects of structural complexity, diel variation in fish-microhabitat relationships, and choice of intervention assessment metric (i.e. taxonomic vs functional diversity).
README: Data from: Fish responses to manipulated microhabitat complexity in urbanised shorelines
This dataset is associated to the published paper "Fish responses to manipulated microhabitat complexity in urbanised shorelines". The study tested whether manupulated microhabtat complexity influences fish diversity and assemblage composition at two spatial scales (microhabitat and whole-structure scales) and across diel cycles as well as diurnal and nocturnal fish-microhabitat size relationships.
Experimental setup and sampling protocols
We constructed four replicates of three habitat enhancement units called 'fish houses' with varying degrees of habitat complexitry (Simple, Complex, and Freestyle), made of concrete blocks and installed them at the base of rip-rap seawalls in October 2019. Both the Simple and Complex fish houses were cuboid, had the same surface area and volume, and included 100 holes (microhabitats). The holes in Simple fish houses were all the same size, whereas 25 size variations were used in the Complex design (volume-independent manipulation of a single complexity element). The Freestyle fish house was non-cuboid and had more overall volume, microhabitat types and sizes.
Fish surveys were conducted during daytime and nighttime. Diurnal fish assemblages were surveyed using underwater video cameras (1 h per sampling) with six repeated measures in March 2020 and July-September 2020 while the night surveys were carried out visually via SCUBA diving with five repeated measures in August-October 2020.
This study examined the volume-independent (Simple vs Complex fish houses) and volume-dependent (Freestyle fish house) effects of microhabitat complexity on fish taxonomic and functional assemblage metrics at two spatial scales and across diel cycles as well as diurnal and nocturnal fish-microhabitat size relationships.
Description of the data and file structure
The dataset consists of seven files below:
'day_diversity.csv' and 'night_diversity.csv' contain the taxonomic and functional diversity metrics per fish house namely, abundance (n), species richness (sr), Shannon’s diversity index (H), Pielou’s evenness index (J), functional richness (FRic), Rao’s quadratic entropy (RaoQ) and functional evenness (FEve) at microhabitat and whole-structure (only for day surveys) scales during daytime and nightime, respectively. Microhabitat- and structure-scale abundances were calculated based on count per 1 h and MeanCount per frame for day surveys, respectively while count per fish house was used for night surveys. Both microhabitat- and structre-scale species richness was count of species per sampling. For more details on functional traits, please see Supporting Information Table S3.
'microhabitat_taxo_composition.csv' and 'microhabitat_func_composition.csv' contain abundance (count per fish house) of each species and community-weighted mean (CWM) values of each functional trait per fish house at the microhabitat scale, respectively.
'structure_taxo_composition.csv' and 'structure_func_composition.csv' contain abundance (MeanCount per frame) of each species and community-weighted mean (CWM) values of each functional trait per fish house at the whole-structure scale, respectively.
'size-matching_relationship.csv' includes the total length (tl in cm) and body depth (bd in cm) of fish that utilised microhabitats within fish houses and the volume of microhabitats utilised by them (per observation) during daytime and nighttime. The information about hole type and hole volume (cm3) is available in Supporting Information Figure S2.