DOI: 10.5061/dryad.1vhhmgr42
title: Data from: Non-native species affect the long-term dynamics of native stream fish assemblages

description: Characterizing the temporal changes of biotic communities and
 disentangling the importance of their driving mechanisms are central
 themes in ecology and environmental management. Non-native species have
 multiple adverse impacts on native communities and species. However, there
 is a dearth of information on how non-natives influence the long-term
 dynamics of native communities. In this study, we compared the role of
 non-native species alongside various local and regional factors in the
 long-term dynamics of stream fish assemblages in the catchment area of
 Lake Balaton, Hungary, the largest lake in Central-Europe. Although, we
 found no consistent trend in species re-ordering between native and
 non-native species, native fish assemblages indicated significantly lower
 temporal stability with increasing relative abundance of co-occurring
 non-natives. Structural equation modelling revealed that assemblage
 dynamic patterns were also determined by a habitat gradient influenced by
 both natural and human-induced processes. Moreover, habitat degradation
 and the presence of fishponds increased the relative abundance of
 non-native species, further affecting native assemblages through indirect
 interactions. Fish assemblage dynamics also exhibited a certain degree of
 finer-scale spatial structure highlighting the need for tailored
 management strategies for each stream. Non-metric multidimensional scaling
 reinforced the destabilizing effect of non-native species but highlighted
 that native fish assemblages could generally be described by
 non-directional gradual or saltatory changes over time, regardless of the
 relative abundance of non-natives. Our results thus revealed that the
 studied native fish assemblages may possess some degree of resilience
 against biological invasions. However, increasing temporal variability
 induced by non-natives makes native assemblages more vulnerable to
 environmental stochasticity threatening their long-term persistence. This
 is especially worrying, since the frequency and intensity of environmental
 disturbances are expected to rise in the future due to climate change and
 increasing anthropogenic pressure on aquatic ecosystems.
description: # Data from: Non-native species affect the long-term dynamics of native
 stream fish assemblages Dataset DOI:
 [10.5061/dryad.1vhhmgr42](10.5061/dryad.1vhhmgr42) ## Description of the
 data and file structure This dataset includes the collected raw biotic
 data (i.e. fish abundance from 2006-2023), environmental data and spatial
 variables for the study "Non-native species affect the long-term
 dynamics of native stream fish assemblages". ### Files and variables
 #### Descripton: 1\. Fish.csv * Sites: Site ID - Year: Sampling year * The
 additional colums contain the scientific names of the species with the raw
 abundance data 2\. Environment.csv * Sites: Site ID - The additional
 columns contain the mean values of the environmental variables among
 sampling years: \- Artificial_surfaces (%) - Agricultural_areas (%)-
 Forests (%) - Non_forest_vegetation (%) - Wetlands (%) - Water bodies (%):
 % of land use types of each stream subcatchment \- Elevation(m): elevation
 \- Width(m): stream width \- Depth(cm): water depth \- Water velocity
 (cm/s): water velocity \- Riparian_herbaceous (%) - Riparian_arboreal (%)
 - Riparian_concrete (%): % of habitat structure of the stream margin along
 a ~10 m wide strip in both sides \- Substratum_Silt/silty-sand (%) -
 Substratum_sand (%) - Substratum_Gravel (%) - Substratum_Stone (%) -
 Substratum_Rock (%) - Substratum_Concrete (%): % of substraum types \-
 Hydrophyte_emergent (%) - Hydrophyte_submerged (%) -
 Hydrophyte_floating-leaved (%) - Hydrophyte_filamentous algae (%) -
 Hydrophyte_plant free area (%): % of aquatic vegetation \- Dissolved
 oxygen (mg/l) - Conductivity_SPC (µS) - Total Dissolved Solids - pH -
 Nitrate N (mg/l) - Nitrite N (mg/l) - Ammonia N (mg/l) - Ortho-phosphate P
 (µg/l): chemical variables 3\. Spatial.csv: * Site_ID: Site ID - PCNM
 1-31: spatial variables resulted from a principal coordinates of neighbour
 matrix analysis (PCNM) based on Euclidean watercourse distance among the
 sampled sites