Natural variation of profundal macroinvertebrate communities in boreal lakes is related to lake morphometry: implications for bioassessment

Abstract

Modern biological assessment of aquatic systems is often based on the reference condition approach, which requires characterization of biota in undisturbed conditions. For this approach, it is essential to recognize the origins and degree of natural variation in communities. We used data from 55 minimally disturbed Finnish lake basins to investigate the natural variation of profundal macroinvertebrate community composition in relation to environmental factors. Partial canonical correspondence analysis showed that most (68% combined, 39% uniquely) of the total explained compositional variation (29%) was correlated with environmental variables insensitive to human activities, especially lake morphometry. In contrast, the unique contributions of geographical location and variables influenced by human activities (dissolved oxygen and total phosphorus) were substantially smaller (5.5% and 22%, respectively). All of the explained variation (38%-64%) of three widely used community metrics was also correlated with human-insensitive environmental factors. The results suggest that variation in undisturbed profundal invertebrate communities of reference sites is strongly dependent on variables insensitive to human activities and especially on those related to lake morphometry, suggesting that reference communities for bioassessment of impacted lakes should be rather predictable from these variables.Résumé : L'évaluation biologique moderne des systèmes aquatiques se fonde souvent sur une méthodologie basée sur les conditions témoins, ce qui exige la caractérisation des organismes vivants dans des conditions non perturbées. Dans cette méthode, il est essentiel de connaître l'origine et l'étendue de la variation naturelle des communautés. Nous utilisons des données provenant de 55 bassins lacustres de Finlande avec des perturbations minimales pour étudier la variation naturelle de la composition des communautés de macroinvertébrés de la zone profonde en fonction des facteurs de l'environnement. Une analyse canonique partielle des correspondances montre que la majeure partie (68 % en combinaison, 39 % entière-ment) de la variation totale de la composition (29 %) est en corrélation avec des variables du milieu qui ne sont pas affectées par les activités humaines, en particulier les caractéristiques morphométriques des lacs. En revanche, les contributions particulières de la situation géographique et des variables affectées par les activités humaines (oxygène dissous et phosphore total) sont substantiellement moins importantes (respectivement 5,5 % et 22 %). Toute la variation expliquée (38 % à 64 %) de trois métriques de communauté d'utilisation courante est aussi reliée aux facteurs du milieu non affectés par les humains. Ces résultats indiquent que la variation dans les communautés profondes non perturbées d'invertébrés des sites témoins est fortement dépendante de variables insensibles aux activités humaines et particulièrement de celles qui sont reliées à la morphologie lacustre, ce qui laisse croire que les communautés témo...

The importance of sedimenting organic matter, relative to oxygen and temperature, in structuring lake profundal macroinvertebrate assemblages

“…; Paranig, Paracladopelma nigritula; Sticros, Stictochironomus rosenschoeldi; Sergcor, Sergentia coracina; Hetapi, Heterotanytarsus apicalis; Hetsub, Heterotrissocladius subpilosus; Hetgri, Heterotrissocladius grimshawi; Mesothi, Mesocricotopus thienemanni; Monbat, Monodiamesa bathyphila; Stembaus, Stempellina bausei; Monoaff, Monoporeia affinis; Palqua, Pallasea quadrispinosa; Prooli, Prodiamesa olivacea; Polynub, Polypedilum nubeculosum; Polypul, Polypedilum pullum; Projacu, Propsilocerus jacuticus; Crypdef, Cryptochironomus defectus gr. ; Mysrel, Mysis relicta However, it is consistent with our previous findings (Jyväsjärvi et al, 2009) of a strong correlation between BQI and lake depth among minimally disturbed lakes because variation in hypolimnetic temperature is closely associated with lake depth (in this study, r = 0.69; see also Ottosson & Abrahamsson, 1998).…”

“…This is supported by community-level studies suggesting that lake-bottom temperature regulates the profundal macroinvertebrate abundance and species composition (e.g. Rasmussen & Kalff, 1987;Dinsmore et al, 1999;Jyväsjärvi et al, 2009).…”

“…Earlier studies have shown that profundal community structure within and among boreal lakes varies with morphometry, and with lake depth in particular (Johnson & Wiederholm, 1989;Hynynen et al, 1999;Jyväsjärvi et al, 2009). This is not surprising as lake morphometry effectively integrates variation in hypolimnetic oxygen and thermal conditions.…”

“…The dataset comprises lakes with varying human disturbance and covers most of the macroinvertebrate assemblage (Jyväsjärvi et al, 2009) and environmental (Simola & Arvola, 2005) variation among Finnish lakes (Table 1). By sampling 2-5 sub-basins with varying morphometry from the 6 study lakes (Table 1), we aimed also to encompass within-lake variation of macroinvertebrate assemblages and their environment.…”

“…As above, species data and environmental variables with skewed distributions were log 10 and X 0.1 -transformed, respectively. More specifically, a partial canonical correspondence analysis (pCCA) with Monte Carlo permutation test (9999 permutations) was used to quantify the individual contributions of TEMP, DO and SOM (Borcard et al, 1992;Økland & Eilertsen, 1994;Jyväsjärvi et al, 2009). First, the total explicable variation was determined using all predictors as constraining variables.…”