DOI: 10.5061/dryad.j6q573nqr
title: Data from: Fish modulate how connectivity and local factors shape food webs of permanent ponds

description: The propagation of metacommunity processes through local trophic
 interactions has seldom been explored, particularly in empirical studies.
 This study examines how local environmental conditions and metacommunity
 connectivity influence community assembly and food web structure in
 pondscapes. We survey taxonomic richness, abundance, and isotopic niches
 across multiple assemblage, including zooplankton, macroinvertebrates,
 tadpoles, turtles, and fish. A gradient in the composition of the pond
 community representing the dominance of fish or other taxa and another
 gradient associated with macroinvertebrate diversity were evidenced. Pond
 size and connectivity promoted fish richness and abundance, representing
 the main path through which metacommunity processes cascade down within
 communities, determining the assembly of the whole system. The dominance
 of fish was associated with large food chains, a reduction in the width of
 the food web width, and the trophic spacing. Local conditions such as
 macrophyte coverage and pond size modulate the strength of these fish
 effects, determining the representation of macroinvertebrates and
 amphibians. Consequently, the effects of pond connectivity on community
 assembly may result as a consequence of isolation's influence on top
 predators' performance, rather than by the direct effect of dispersal
 on different species, as is usually assumed. Metacommunity theory has
 highlighted the direct effect of dispersal on species performance and
 diversity. Our study highlights the indirect influence of landscape
 mediated by keystone species, which connect metacommunity dispersal with
 local community processes more than previously thought.
description: The data were collected in two pondscapes located in the
 grassland landscape of Uruguay, where sampling was conducted in permanent
 ponds to assess taxonomic richness, abundance, and isotopic niches of
 different assemblages, including zooplankton, macroinvertebrates,
 tadpoles, turtles, and fish. The sampling was designed to explore how
 local conditions and metacommunity connectivity influence community
 structure and food web dynamics, as described in the forthcoming article
 titled 'Fish modulate how connectivity and local factors shape food
 webs of permanent ponds' (to be published in
 <em>Oikos</em>). Following data collection, the data were
 processed using statistical analyses in R, including data cleaning and
 correction for sampling effort, as well as analyses to evaluate trophic
 interactions and the effects of connectivity and local conditions on
 community composition and food web structure.
description: # Fish modulate how connectivity and local factors shape food webs of
 permanent ponds
 [https://doi.org/10.5061/dryad.j6q573nqr](https://doi.org/10.5061/dryad.j6q573nqr) ## Description of the data and file structure The data was collected as part of a study investigating how local environmental conditions and metacommunity connectivity influence community assembly and food web structure in pondscapes. The research focused on assessing taxonomic richness, abundance, and isotopic niches across various assemblages, including zooplankton, macroinvertebrates, tadpoles, turtles, and fish. Sampling was conducted in multiple ponds across two pondscapes in Uruguay. The dataset includes local environmental variables of the ponds, such as area, maximum depth, macrophyte coverage, and edge heterogeneity, as well as centrality measures. Additionally, the dataset includes community-level variables such as abundance and richness of different assemblages, along with isotopic niche metrics. ### Files and variables #### File: data\_ms.csv **Description:**  ##### Variables * pond_id: Unique identifier for each pond in the study. * region: Geographical region of the pond, represented by categories such as "Paysandú" or "Aceguá." * weighted_degree_centrality_std: Standardized measure of weighted centrality in the connectivity network of ponds, used to facilitate comparisons between ponds.  * area_ellipse: Area of the pond estimated using an ellipse fitted to the shape of the pond, in square meters (m²). * max_depth: Maximum depth of the pond, measured in meters. * ph: pH level of the water in the pond. * temperature: Water temperature in the pond, measured in degrees Celsius. * conductivity: Electrical conductivity of the water in the pond, in microsiemens per centimeter (μS/cm). * o_dis_porc: Percentage of dissolved oxygen in the water. * o_dis_mg: Concentration of dissolved oxygen in the water, measured in milligrams per liter (mg/L). * tds: Total dissolved solids in the water, measured in parts per million (ppm). * salinity: Salinity of the water, measured in concentration units of salt. * turbidity: Water turbidity, measured in nephelometric turbidity units (NTU). * macrophyte_cover: Cover of macrophytes (aquatic plants) in the pond, expressed as the percentage of area covered by these plants. * edge_heterogeneity: Heterogeneity of the pond's edge, reflecting the diversity of features along the pond's borders, such as the presence of different types of vegetation or structures. * fishes_seac: Standard Ellipse Area with Sample Size Correction (SEAC) for fish, representing the ecological niche occupied by fish species, adjusted for sample size. This metric reflects the isotopic niche space for fish within the pond. * macroinvertebrates_seac: Standard Ellipse Area with Sample Size Correction (SEAC) for macroinvertebrates, representing the ecological niche occupied by macroinvertebrate species, adjusted for sample size. This metric reflects the isotopic niche space for macroinvertebrates within the pond. * tadpoles_seac: Standard Ellipse Area with Sample Size Correction (SEAC) for tadpoles, representing the ecological niche occupied by tadpole species, adjusted for sample size. This metric reflects the isotopic niche space for tadpoles within the pond. * SEAc: Total Standard Ellipse Area with Sample Size Correction (SEAC) for all groups combined, representing the overall ecological niche space occupied by the different trophic groups in the pond, adjusted for sample size. * N_range: Nitrogen isotopic range, indicating the variability in nitrogen isotopic values among the organisms in each pond. * C_range: Carbon isotopic range, indicating the variability in carbon isotopic values among the organisms in each pond. * TA: Trophic width, a measure of the food chain's breadth in a pond, determined by the trophic separation between different organisms. * CD: Centroid distance, mean Euclidean distance of each species from the food web centroid, reflecting the average trophic diversity and spacing between species * NND: Nearest Neighbor Distance, represents the mean euclidean distance of each species to the nearest neighbour species within the biplot and indicates the trophic spacing of species. * SDNND: Standard deviation of Nearest Neighbor Distance, describes the evenness of this packing, where lower values indicate a uniform distribution of trophic niches for each species in a food web * offset_seine_fish: Sampling effort with the seine fish net, measured in meters of net haul. This variable represents the amount of effort applied to capture macroinvertebrates, tadpoles and fishes in the study ponds. * offset_zoo: Sampling effort for zooplankton, measured as the volume of water filtered during sampling. This variable represents the amount of effort applied to collect zooplankton in the study ponds. * n_tadpoles: Tadpole abundance in the pond, expressed as the total number of tadpole individuals. * n_fishes: Fish abundance in the pond, expressed as the total number of fish individuals. * n_macroinvertebrates: Macroinvertebrate abundance in the pond, expressed as the total number of macroinvertebrate individuals. * n_zooplankton: Zooplankton abundance in the pond, expressed as the total number of zooplankton individuals. * s_tadpoles: Tadpole species richness in the pond, measured as the number of different tadpole species present. * s_macroinvertebrates: Macroinvertebrate species richness in the pond, measured as the number of different macroinvertebrate species present. * s_fishes: Fish species richness in the pond, measured as the number of different fish species present. * s_total: Total species richness in the pond, including the combined richness of tadpoles, macroinvertebrates and fishes species. Missing data: NA ## Code/software The data analysis was performed using common R packages and functions, as detailed in the methodology of the paper. The analysis included Principal Component Analysis (PCA), Principal Coordinate Analysis (PCoA), and model selection procedures, all of which are standard approaches in ecological research. These models are implemented with widely used packages like `lme4` for statistical modeling. For further details on the analysis, please refer to the article's methodology section.