Many freshwater ecosystems rely on the decomposition of organic matter as a key process for nutrient cycling and energy flow. Small lentic freshwater ecosystems, such as ponds, often derive a large amount of energy from allochthonous detritus due to their close connection with the terrestrial environment. However, the process of leaf litter decomposition in ponds remains poorly understood. We conducted a microcosm experiment in a pond environment to investigate intra- and inter-specific variation in organic matter processing by three shredders (Tipula sp., Sericostoma sp. and Gammarus fossarum) and to assess the effects of shredder community characteristics on the mass loss of black alder (Alnus glutinosa) leaf litter. We developed a novel approach to quantify functional traits directly related to litter processing. Detailed gut content analysis revealed significant inter- and intra-specific variation in the organic matter particles ingested by individual shredder taxa. Our results showed that neither taxonomic nor functional diversity reliably predicts leaf litter decomposition rates in ponds. Instead, the keystone shredder Sericostoma showed a pronounced effect on decomposition rates driven by their unique feeding behaviour and density-dependent shifts in particle size preferences. These findings highlight the importance of a detailed understanding of species-specific functional traits and behaviour in shaping ecosystem processes, as the role of keystone species can outweigh the contributions of overall diversity measures in driving ecosystem processes.

Department of Biology and General Ecology Faculty of Ecology and Environmental Sciences Technical University in Zvolen Zvolen Slovakia

Department of Forest Ecology Faculty of Forestry and Wood Sciences Czech University of Life Sciences Prague Prague Czech Republic

Institute of Botany Plant Science and Biodiversity Centre Slovak Academy of Sciences Bratislava Slovakia

Zobrazit více v PubMed

Gessner MO, Swan CM, Dang CK, McKie BG, Bardgett RD, Wall DH, et al. Diversity meets decomposition. Trends Ecol Evol. 2010;25(6):372–80. doi: 10.1016/j.tree.2010.01.010 PubMed DOI

Cummins KW, Wilzbach MA, Gates DM, Perry JB, Taliaferro WB. Shredders and riparian vegetation: Leaf litter that falls into streams influences communities of stream invertebrates. BioScience. 1989;39:42–30.

Webster JR, Benfield EF. Vascular plant breakdown in freshwater ecosystems. Annu Rev Ecol Syst. 1986;17:567–94.

Oertli B. Leaf litter processing and energy flow through macroinvertebrates in a woodland pond (Switzerland). Oecologia. 1993;96(4):466–77. doi: 10.1007/BF00320503 PubMed DOI

Earl JE, Semlitsch RD. Reciprocal subsidies in ponds: Does leaf input increase frog biomass export? Oecologia. 2012;170(4):1077–87. doi: 10.1007/s00442-012-2361-5 PubMed DOI

Benetti CJ, Pérez-Bilbao A, Garrido J. The determination of food sources for invertebrates in four ponds in NW Spain using stable isotope analysis. Limnetica. 2014;(33):89–106. doi: 10.23818/limn.33.08 DOI

Gessner MO, Chauvet E, Dobson M. A perspective on leaf litter breakdown in streams. Oikos. 1999;85(2):377–84. doi: 10.2307/3546505 DOI

Benfield EF, Fritz KM, Tiegs SD. Leaf-litter breakdown. In: Hauer FR, Lamberti GA, editors. Methods in stream ecology: volume 2: ecosystem structure. 3rd ed. Academic Press; 2017. p. 71–82. doi: 10.1016/b978-0-12-813047-6.00005-x DOI

Magurran A. Measuring biological diversity. Blackwell Publishing; 2004.

Jonsson M, Malmqvist B. Ecosystem process rate increases with animal species richness: Evidence from leaf‐eating, aquatic insects. Oikos. 2000;89(3):519–23. doi: 10.1034/j.1600-0706.2000.890311.x DOI

Jonsson M, Malmqvist B, Hoffsten P. Leaf litter breakdown rates in boreal streams: Does shredder species richness matter? Freshw Biol. 2001;46:161–71.

Hooper DU, Solan M, Symstad A, Diaz S, Gessner MO, Buchmann N. Species diversity, functional diversity and ecosystem functioning. In: Loreau M, Naeem S, Inchausti P, editors. Biodiversity and ecosystem functioning: synthesis and perspectives. Oxford University Press; 2002. p. 195–208.

Schmera D, Heino J, Podani J, Erős T, Dolédec S. Functional diversity: A review of methodology and current knowledge in freshwater macroinvertebrate research. Hydrobiologia. 2016;787(1):27–44. doi: 10.1007/s10750-016-2974-5 DOI

Abonyi A, Horváth Z, Ptacnik R. Functional richness outperforms taxonomic richness in predicting ecosystem functioning in natural phytoplankton communities. Freshw Biol. 2018;63:178–86.

Jarzyna MA, Jetz W. Taxonomic and functional diversity change in scale dependent. Nat Commun. 2018;9:1–8. PubMed PMC

Reiss J, Bailey RA, Perkins DM, Pluchinotta A, Woodward G. Testing effects of consumer richness, evenness and body size on ecosystem functioning. J Anim Ecol. 2011;80(6):1145–54. doi: 10.1111/j.1365-2656.2011.01857.x PubMed DOI

Dekanová V, Novikmec M, Svitková I, Svitok M. Functional diversity of shredders, not species richness, drives the decomposition rate of leaf litter in ponds. Front Ecol Evol. 2023;11:1286672. 10.3389/fevo.2023.1286672 DOI

Cadotte MW, Carscadden K, Mirotchnick N. Beyond species: Functional diversity and the maintenance of ecological processes and services. J Appl Ecol. 2011;48:1079–87.

Tilman D. Functional diversity. In: Levin SA, editor. Encyclopedia of biodiversity. Elsevier; 2001. p. 109–20. doi: 10.1016/b0-12-226865-2/00132-2 DOI

Petchey OL, Gaston KJ. Functional diversity: Back to basics and looking forward. Ecol Lett. 2006;9(6):741–58. doi: 10.1111/j.1461-0248.2006.00924.x PubMed DOI

Frainer A, McKie BG, Malmqvist B. When does diversity matter? Species functional diversity and ecosystem functioning across habitats and seasons in a field experiment. J Anim Ecol. 2014;83(2):460–9. doi: 10.1111/1365-2656.12142 PubMed DOI

Tonin AM, Pozo J, Monroy S, Basaguren A, Pérez J, Gonçalves JF Jr, et al. Interactions between large and small detritivores influence how biodiversity impacts litter decomposition. J Anim Ecol. 2018;87(5):1465–74. doi: 10.1111/1365-2656.12876 PubMed DOI

Cummins KW, Klug MJ. Feeding ecology of streams invertebrates. Annu Rev Ecol Evol Syst. 1979;10:147–72.

Ramírez A, Gutiérrez-Fonseca PE. Functional feeding groups of aquatic insect families in Latin America: A critical analysis and review of existing literature. Rev Biol Trop. 2014;62 Suppl 2:155–67. doi: 10.15517/rbt.v62i0.15785 PubMed DOI

Walker BH. Biodiversity and ecological redundancy. Conserv Biol. 1992;6:18–23.

Tilman D, Knops J, Wedin D, Reich P, Ritchie M, Siemann E. The influence of functional diversity and composition on ecosystem processes. Science. 1997;277(5330):1300–2. doi: 10.1126/science.277.5330.1300 DOI

Albouy C, Guilhaumon F, Villéger S, Mouchet M, Mercier L, Culioli JM. Predicting trophic guild and diet overlap from functional traits: Statistics, opportunities and limitations for marine ecology. Mar Ecol Prog Ser. 2011;436:17–28.

Jonsson M, Malmqvist B. Importance of species identity and number for process rates within different stream invertebrate functional feeding groups. J Anim Ecol. 2003;72:453–9.

Friberg N, Jacobsen D. Feeding plasticity of two detritivore-shredders. Freshw Biol. 1994;32:133–42.

Wantzen KM, Wagner R. Detritus processing by invertebrate shredders: A neotropical–temperate comparison. J North Am Benthol Soc. 2006;25(1):216–32. doi: 10.1899/0887-3593(2006)25[216:dpbisa]2.0.co;2 DOI

Graça MAS, Maltby L, Calow P. Importance of fungi in the diet of PubMed DOI

Iwai N, Pearson RG, Alford RA. Shredder–tadpole facilitation of leaf litter decomposition in a tropical stream. Freshw Biol. 2009;54:2573–80.

Dangles O, Malmqvist B. Species richness–decomposition relationships depend on species dominance. Ecol Lett. 2004;7:395–402.

Encalada AC, Calles J, Ferreira V, Canhoto CM, Graça MAS. Riparian land use and the relationship between the benthos and litter decomposition in tropical montane streams. Freshw Biol. 2010;55:1719–33.

Boyero L, Cardinale BJ, Bastian M, Pearson RG. Biotic vs. abiotic control of decomposition: A comparison of the effects of simulated extinctions and changes in temperature. PLoS One. 2014;9(1):e87426. doi: 10.1371/journal.pone.0087426 PubMed DOI PMC

Santonja M, Pellan L, Piscart C. Macroinvertebrate identity mediates the effects of litter quality and microbial conditioning on leaf litter recycling in temperate streams. Ecol Evol. 2018;8(5):2542–53. doi: 10.1002/ece3.3790 PubMed DOI PMC

Jonsson M, Sponseller RA. The role of macroinvertebrates on plant litter decomposition in streams. In: Swan CM, Boyero L, Canhoto C, editors. The ecology of plant litter decomposition in stream ecosystems. Springer International Publishing; 2021. p. 193–216. doi: 10.1007/978-3-030-72854-0_10 DOI

Voß K, Schäfer RB. Taxonomic and functional diversity of stream invertebrates along an environmental stress gradient. Ecol Indic. 2017;81:235–42.

Brett MT, Bunn SE, Chandra S, Galloway AWE, Guo F, Kainz MJ. How important are terrestrial organic carbon inputs for secondary production in freshwater ecosystems? Freshw Biol. 2017;62:833–53.

Stoler AB, Relyea RA. Reviewing the role of plant litter inputs to forested wetland ecosystems: Leafing through the literature. Ecol Monogr. 2020;90:e01400.

Fortino K, Tacik L. Leaf litter density and decomposition in small man-made ponds. Authorea; 2017. Available from: https://www.authorea.com/users/15752/articles/186037-leaf-litter-density-and-decomposition-in-small-man-made-ponds#

Dekanová V, Svitková I, Novikmec M, Svitok M. Litter breakdown of invasive alien plant species in a pond environment: Rapid decomposition of DOI

Thornhill I, Friberg N, Batty L, Thamia V, Ledger ME. Leaf breakdown rates as a functional indicator were influenced by an invasive non-native invertebrate in urban ponds. Ecol Indic. 2021;124:107360.

Canhoto C, Graça MAS. Digestive tract and leaf processing capacity of the stream invertebrate

Pérez J, Basaguren A, López-Rojo N, Tonin AM, Correa-Araneda F, Boyero L. The role of key plant species on litter decomposition in streams: Alder as experimental model. In: Swan CM, Boyero L, Canhoto C, editors. The ecology of plant litter decomposition in stream ecosystems. Springer International Publishing; 2021. p. 143–61. doi: 10.1007/978-3-030-72854-0_8 DOI

Anderson NH, Sedell JR. Detritus processing by macroinvertebrates in stream ecosystems. Annu Rev Entomol. 1979;24:351–77.

Bärlocher F. The role of fungi in the nutrition of stream invertebrates. Bot J Linn Soc. 1985;91:83–94.

Suberkropp K, Chauvet E. Regulation of leaf breakdown by fungi in streams: Influences of water chemistry. Ecology. 1995;76(5):1433–45. doi: 10.2307/1938146 DOI

Pascoal C, Fernandes I, Seena S, Danger M, Ferreira V, Cássio F. Linking microbial decomposer diversity to plant litter decomposition and associated processes in streams. In: Swan CM, Boyero L, Canhoto C, editors. The ecology of plant litter decomposition in stream ecosystems. Springer International Publishing; 2021. p. 163–92. doi: 10.1007/978-3-030-72854-0_9 DOI

Gessner MO, Chauvet E. Importance of stream microfungi in controlling breakdown rates of leaf litter. Ecology. 1994;75(6):1807–17. doi: 10.2307/1939639 DOI

Foucreau N, Puijalon S, Hervant F, Piscart C. Effect of leaf litter characteristics on leaf conditioning and on consumption by

Jażdżewski K. Morfologia, Taksonomia i Występowanie w Polsce Kiełży z Rodzajów

Hofsvang T. Diptera: Tipulidea. In: Nillson A, editor. The aquatic insects of North Europe: a taxonomic handbook: Volume 2. Stenstrup: Apollo Books; 1997. p. 93–9.

Waringer J, Graf W. Atlas of Central European Trichoptera Larvae (Atlas der mitteleuropäischen Köcherfliegenlarven). Erik Mauch Verlag; 2011.

Asochakov IA. Technique for measuring body length of amphipods. Hydrobiol J. 1994;30:107–10.

Felten V, Tixier G, Guérold F, De Crespin De Billy V, Dangles O. Quantification of diet variability in a stream amphipod: Implications for ecosystem functioning. Fundam Appl Limnol. 2008;170:303–13.

Schneider CA, Rasband WS, Eliceiri KW. NIH image to ImageJ: 25 years of image analysis. Nat Methods. 2012;9(7):671–5. doi: 10.1038/nmeth.2089 PubMed DOI PMC

Sicheng A, Chiu MC, Lin X, Cai Q. Trait selection strategy for functional diversity in freshwater systems: A case framework of macroinvertebrates. Ecol Indic. 2023;153:110450.

Šporka F, Bitušík P, Bulánková E, Cséfalvay R, Čejka T, Derka T. Aquatic macroinvertebrates of Slovakia: Species list and autecological characteristics (Vodné bezstavovce (makroevertebráta) Slovenska, súpis druhov a autekologické charakteristiky). Slovak Hydrometeorological Institute; 2003.

Rao CR. Diversity and dissimilarity coefficients: A unified approach. Theor Pop Biol. 1982;21:24–43.

Botta‐Dukát Z. Rao’s quadratic entropy as a measure of functional diversity based on multiple traits. J Veg Sci. 2005;16:533–40.

Pastore M, Calcagnì A. Measuring distribution similarities between samples: A distribution-free overlapping index. Front Psychol. 2019;10:1089. doi: 10.3389/fpsyg.2019.01089 PubMed DOI PMC

Pinheiro JC, Bates DM. Mixed-effects models in S and S-PLUS. Springer; 2000.

Nakagawa S, Kar F, O’Dea RE, Pick JL, Lagisz M. Divide and conquer? Size adjustment with allometry and intermediate outcomes. BMC Biol. 2017;15(1):107. doi: 10.1186/s12915-017-0448-5 PubMed DOI PMC

Dunn KP, Smyth GK. Randomized quantile residuals. J Comput Graph Stat. 1996;5:1–10.

Staggs VS. Comparison of naïve, Kenward–Roger, and parametric bootstrap interval approaches to small-sample inference in linear mixed models. Commun Stat Simul Comput. 2017;46:1933–43.

Singmann H, Kellen D. An introduction to mixed models for experimental psychology. In: Spieler DH, Schumacher E, editors. New methods in cognitive psychology. Psychology Press; 2019. p. 4–31. doi: 10.4324/9780429318405-2 DOI

Lenth RV. Least-squares means: the R package ismeans. J Stat Softw. 2016;69:1–33.

Nakagawa S, Johnson PCD, Schielzeth H. The coefficient of determination R2 and intra-class correlation coefficient from generalized linear mixed-effects models revisited and expanded. J R Soc Interface. 2017;14(134):20170213. doi: 10.1098/rsif.2017.0213 PubMed DOI PMC

Ferrari S, Cribari-Neto F. Beta regression for modelling rates and proportions. J Appl Stat. 2004;31:799–815.

Cribari-Neto F, Zeileis A. Beta regression in R. J Stat Softw. 2010;34:1–24.

R Core Team. R: a Language and Environment for Statistical Computing. R Foundation for Statistical Computing; 2022. [cited 2024 Feb 16]. Available from: https://www.R-project.org/

Hartig F. DHARMa: residual diagnostics for hierarchical (multi-level/ mixed) regression models. R package version 0.4.6.; 2022 [cited 2024 Feb 16]. Available from: https://CRAN.R-project.org/package=DHARMa

Lenth R. Emmeans: estimated marginal means, aka least-squares means. R package version 1.10.3.; 2024 [cited 2024 Feb 16]. Available from: https://CRAN.R-project.org/package=emmeans

Wickham H. Ggplot2: elegant graphics for data analysis. 2nd ed. New York: Springer-Verlag; 2016.

Wilke C. Ggridges: ridgeline plots in ‘ggplot2’. R package version 0.5.4.; 2022 [cited 2024 Feb 16]. Available from: https://wilkelab.org/ggridges

Bates D, Maechler M, Bolker B, Walker S. Fitting linear mixed-effects models using lme4. J Stat Softw. 2015;67:1–48.

Kuznetsova A, Brockhoff PB, Christensen RHB. lmerTest package: Tests in linear mixed effects models. J Stat Softw. 2017;82:1–26.

Pastore M, Loro PAD, Mingione M, Calcagni A. Overlapping: Estimation of overlapping in empirical distributions. R package version 2.1.; 2022 [cited 2024 Feb 16]. Available from: https://CRAN.R-project.org/package=overlapping

Lüdecke D, Ben-Shachar M, Patil I, Waggoner P, Makowski D. performance: An R package for assessment, comparison and testing of statistical models. JOSS. 2021;6(60):3139. doi: 10.21105/joss.03139 DOI

Oksanen J, Simpson G, Blanchet F, Kindt R, Legendre P, Minchin P, et al. Vegan: Community ecology package. R package version 2.6-2.; 2022 [cited 2024 Feb 16]. Available from: https://cran.r-project.org/web/packages/vegan/index.html

Petersen RC, Cummins KW. Leaf processing in a woodland stream. Freshw Biol. 1974;4:343–68.

Rota T, Lecerf A, Chauvet É, Pey B. The importance of intraspecific variation in litter consumption rate of aquatic and terrestrial macro-detritivores. Basic Appl Ecol. 2022;63:175–85. doi: 10.1016/j.baae.2022.06.003 DOI

Des Roches S, Post DM, Turley NE, Bailey JK, Hendry AP, Kinnison MT, et al. The ecological importance of intraspecific variation. Nat Ecol Evol. 2018;2(1):57–64. doi: 10.1038/s41559-017-0402-5 PubMed DOI

Bolnick DI, Amarasekare P, Araújo MS, Bürger R, Levine JM, Novak M, et al. Why intraspecific trait variation matters in community ecology. Trends Ecol Evol. 2011;26(4):183–92. doi: 10.1016/j.tree.2011.01.009 PubMed DOI PMC

Palkovacs EP, Fryxell DC, Turley NE, Post DM. Ecological effects of intraspecific consumer biodiversity for aquatic communities and ecosystems. In: Belgrano A, Woodward G, Jacob U, editors. Aquatic functional biodiversity. Elsevier; 2015. p. 37–51.

Raffard A, Santoul F, Cucherousset J, Blanchet S. The community and ecosystem consequences of intraspecific diversity: a meta-analysis. Biol Rev Camb Philos Soc. 2019;94(2):648–61. doi: 10.1111/brv.12472 PubMed DOI

Huryn AD, Huryn VM, Arbuckle CJ, Tsomides L. Catchment land-use, macroinvertebrates and detritus processing in headwater streams: Taxonomic richness versus function. Freshw Biol. 2002;47:401–15.

Dangles O, Crespo-Pérez V, Andino P, Espinosa R, Calvez R, Jacobsen D. Predicting richness effects on ecosystem function in natural communities: insights from high-elevation streams. Ecology. 2011;92(3):733–43. doi: 10.1890/10-0329.1 PubMed DOI

Díaz S, Cabido M. Vive la différence: Plant functional diversity matters to ecosystem processes. Trends Ecol Evol. 2001;16(11):646–55. doi: 10.1016/s0169-5347(01)02283-2 DOI

Urban MC. Disturbance heterogeneity determines freshwater metacommunity structure. Ecology. 2004;85(11):2971–8. doi: 10.1890/03-0631 DOI

Mikola J, Setälä H, Setala H. Relating species diversity to ecosystem functioning: Mechanistic backgrounds and experimental approach with a decomposer food web. Oikos. 1998;83(1):180. doi: 10.2307/3546560 DOI

Vos VCA, van Ruijven J, Berg MP, Peeters ETHM, Berendse F. Macro‐detritivore identity drives leaf litter diversity effects. Oikos. 2010;120(7):1092–8. doi: 10.1111/j.1600-0706.2010.18650.x DOI

Jonsson M, Malmqvist B. Mechanisms behind positive diversity effects on ecosystem functioning: Testing the facilitation and interference hypotheses. Oecologia. 2003;134(4):554–9. doi: 10.1007/s00442-002-1148-5 PubMed DOI

Carvalho EM, Graça MAS. A laboratory study on feeding plasticity of the shredder Sericostoma vittatum Rambur (Sericostomatidae). Hydrobiologia. 2006;575(1):353–9. doi: 10.1007/s10750-006-0383-x DOI

Johansen R, Albright M, Gallegos-Graves LV, Lopez D, Runde A, Yoshida T, et al. Tracking replicate divergence in microbial community composition and function in experimental microcosms. Microb Ecol. 2019;78(4):1035–9. doi: 10.1007/s00248-019-01368-w PubMed DOI

Carl S, Mohr S, Sahm R, Baschien C. Laboratory conditions can change the complexity and composition of the natural aquatic mycobiome on DOI