DOI: 10.5061/dryad.3jj548d
title: Data from: Connectivity and zebra mussel invasion offer short‐term buffering of eutrophication impacts on floodplain lake landscape biodiversity

description: Aim: To investigate if connectivity and zebra mussel (Dreissena
 polymorpha) occurrence can mitigate effects of eutrophication in a lowland
 lake landscape. Location: Upper Lough Erne, Northern Ireland, UK. Methods:
 Data on environment, macrophytes and invertebrates were assembled for
 three basins of a large central lake and its satellite floodplain lakes
 via field surveys and paleolimnological analyses. Space-time interaction
 analyses of paleoecological data were compared pre-1950 and post-1950.
 Multivariate analyses examined how connectivity, environment, and zebra
 mussels influenced contemporary lake communities, and explain their
 divergence from historical communities in the past. Results: Pre-1950, we
 found high community variation across sites and low within-lake variation
 in macrophytes, but progressive eutrophication accentuated within-lake
 community variation after 1950. Partitioning analysis showed larger
 effects of connectivity than nutrient enrichment on contemporary
 macrophyte composition, while local effects structured invertebrate
 communities. Three clusters of lakes were revealed according to variation
 in macrophyte composition, isolation from the central lake and nutrient
 enrichment: Group 1– the central lake and 6 nearby lakes were
 meso-eutrophic (TP=66.7±47.6 μg/l; TN=0.79±0.41 mg/l) and had the highest
 zebra mussel abundances and organismal biodiversity; Group 2– 8 eutrophic
 (TP= 112±36.6 μg/l; TN=1.25±0.5 mg/l) and connected lakes; Group 3– 7
 isolated and hypertrophic (TP=163.2±101.5 μg/l; TN=1.55±0.3 mg/l) lakes.
 Pre-1950 paleolimnological data for macrophytes and invertebrates for 5
 lakes and a basin in the central lake most resembled extant lake
 communities of Group 1. However, paleo-records revealed that macrophytes
 and invertebrates subsequently converged towards those of Groups 2 and 3.
 Main conclusions: Our study reveals that the central “mother” lake acts as
 a hub for preserving biodiversity via shared hydrological connectivity
 with satellite lakes and high zebra mussel abundances. These may buffer
 the impoverishing effects of eutrophication and sustain unexpectedly high
 biodiversity in the short-term. Such protective buffering, however, cannot
 be relied upon indefinitely to conserve biodiversity.
description: Plant macro remains of
 selected lakes in the Upper Lough Erne systemPlant macro remains
 obtained in cores ULET2 (Upper Lough Erne), NCAS3 (Castle Lough), CBRAS1
 (Cornabrass Lough), KILL2 (killymackan Lough) , GOLE1 (Gole Lough) and
 HEAD1 (Lough Head). The sediment material was collected in the field
 during 2008-2009 in the Upper Lough Erne system and analysed in the
 laboratory.Plants_dafor_ST.csvInvertebrate macro remains of selected lakes in the Upper Lough Erne systemInvertebrate macro remains found in cores ULET2 (Upper Lough Erne), NCAS3 (Castle Lough), CBRAS1 (Cornabrass Lough), KILL2 (Killymackan Lough), and HEAD1 (Lough Head). The sediment data was collected in the field during 2008-2009 in the Upper Lough Erne system and analysed in the laboratoryInvertebrates_ST.csvMacrophyte data of contemporary surveysMacrophyte (submerged and floating plants) occurrences data obtained from a site condition assessment of standing water features in the ULE system undertaken for the Northern Ireland Environmental Agency (NIEA) during the summers of 2006-2007 (Goldsmith et al., 2008).Plants_contemporary_freq.csvSub-fossil remain data of invertebrate taxa from 12 lakes in the Upper Lough Erne systemSub-fossil remain data of invertebrate taxa collected in the field in surface sediment samples (uppermost 2 cm) from 12 lakes in the Upper Lough Erne system.Invertebrates_contemporary.csv