Nutrient inputs shape ecosystem functioning gradients along the pristine, upper Neretva River, Bosnia and Herzegovina


  • Rubén Del Campo Department of Ecology, Fluvial Ecosystem Ecology, University of Innsbruck
  • Barbara Jechsmayr Department of Ecology, Fluvial Ecosystem Ecology, University of Innsbruck
  • Veronika Settles Department of Ecology, Fluvial Ecosystem Ecology, University of Innsbruck
  • Melanie Ströder Department of Ecology, Fluvial Ecosystem Ecology, University of Innsbruck
  • Gabriel Singer Department of Ecology, Fluvial Ecosystem Ecology, University of Innsbruck



ecosystem functioning, functional diversity, functional indicators, karst, dissolved organic matter, river networks


Ecosystem functions are the backbone of ecosystem services that rivers provide to human societies. Ecosystem functioning emerges from the interaction between biological communities and their environment. As environmental conditions in rivers change along their longitudinal continuum, so does functioning. Sometimes, these changes do not follow smooth gradients but rather great discontinuities. This can be the case in calcareous, karstic rivers due to the sudden massive inputs of groundwater along the landscape, a typical phenomenon for Balkan rivers. Despite their high geodiversity and their great ecological value, Balkan rivers remain understudied. Here, we investigated how ecosystem functions and their diversity (estimated as multifunctionality) change along the continuum of the karstic, free-flowing Neretva River in Bosnia and Herzegovina. For this purpose, we measured a subset of fundamental ecosystem functions (ecosystem gross primary production, biofilm net primary production and enzymatic activities, organic matter decomposition) in 11 river reaches from the Neretva headwaters to river sections upstream of the Jablanica reservoir. We found different functions reached their maximum in different sections of the Neretva depending on nutrient inputs. While organic matter decomposition was highest in headwaters due to the input of nutrients from riparian vegetation, biofilm enzymatic activity expressed highest values at middle sections due to groundwater inputs of NH4+-N. Primary production was highest at the most downstream sections due to the accumulation of NO3--N and PO43--P within the catchment area. As a result, average multifunctionality peaked at sites with the highest nutrient concentration across the Neretva river continuum, indicating a stronger influence of nutrient inputs than network position. The pristine conditions of the Neretva result in oligotrophic conditions along its upper course. Our results emphasize the great sensitivity of ecosystem functioning in the Neretva to nutrient inputs and environmental discontinuities, either natural or human-made. Potential major, long-term impacts in the area might alter existing environmental gradients and thus ecosystem functioning in rivers at local and regional scale.


Allan JD, Castillo MM. 2009. Stream ecology: structure and function of running waters. Second edition. Dordrecht: Springer.

Altermatt F, Little CJ, Mächler E, Wang S, Zhang X, Blackman RC. 2020. Uncovering the complete biodiversity structure in spatial networks: the example of riverine systems. Oikos. 129: 607–618.

Appling AP, Hall RO, Yackulic CB, Arroita M. 2018. Overcoming equifinality: leveraging long time series for stream metabolism estimation. Journal of Geophysical Research: Biogeosciences. 123: 624–645.

Bakrac A, Rimceska B, Bilbija B, Atanacković A, Džaferović A, Nikolić V, Marković V. 2021. Aquatic macroinvertebrates diversity in the upper stretch of Una river (Una national park, SW Bosnia and Herzegovina). Ecologia Balkanica. 13: 131–141.

Bärlocher F, Gessner MO, Graça MAS, editors. 2020. Methods to study litter decomposition. Cham: Springer International Publishing.

Bernhardt ES, Heffernan JB, Grimm NB, Stanley EH, Harvey JW, Arroita M, Appling A, Cohen M, McDowell WH, Hall RO, et al. 2018. The metabolic regimes of flowing waters. Limnology and Oceanography. 63: S99–S118.

Bernhardt ES, Savoy P, Vlah MJ, Appling AP, Koenig LE, Hall RO, Arroita M, Blaszczak J, Carter AM, Cohen M, et al. 2022. Light and flow regimes regulate the metabolism of rivers. Proceedings of the National Academy of Sciences. 119: e2121976119.

Bianchi TS. 2011. The role of terrestrially derived organic carbon in the coastal ocean: a changing paradigm and the priming effect. Proceedings of the National Academy of Sciences. 108: 19473–19481.

Bonacci O. 2015. Surface Waters and Groundwaters in Karst. In: Stevanović Z, editor. Karst Aquifers. Characterization and Engineering. Cham: Springer International Publishing. p. 149–170.

Borchardt MA. 1996. 7 - Nutrients. In: Stevenson RJ, Bothwell ML, Lowe RL, editors. Algal ecology. Freshwater benthic ecosystems. San Diego (CA): Academic Press. p. 183–227. (Aquatic ecology series)

Byrnes JEK, Gamfeldt L, Isbell F, Lefcheck JS, Griffin JN, Hector A, Cardinale BJ, Hooper DU, Dee LE, Emmett Duffy J. 2014. Investigating the relationship between biodiversity and ecosystem multifunctionality: challenges and solutions. Methods in Ecology and Evolution. 5: 111–124.

Cardinale BJ, Palmer MA, Swan CM, Brooks S, Poff NL. 2002. The influence of substrate heterogeneity on biofilm metabolism in a stream ecosystem. Ecology. 83: 412–422.

Casas‐Ruiz JP, Spencer RGM, Guillemette F, Schiller D, Obrador B, Podgorski DC, Kellerman A, Hartmann J, Gómez-Gener L, Sabater S, et al. 2020. Delineating the continuum of dissolved organic matter in temperate river networks. Global Biogeochemical Cycles. 34: 1–15.

Coble PG. 1996. Characterization of marine and terrestrial DOM in seawater using excitation-emission matrix spectroscopy. Marine Chemistry. 51: 325–346.

Djedjibegovic J, Marjanovic A, Sober M, Skrbo A, Sinanovic K, Larssen T, Grung M, Fjeld E, Rognerud S. 2010. Levels of persistent organic pollutants in the Neretva River (Bosnia and Herzegovina) determined by deployment of semipermeable membrane devices (SPMD). Journal of Environmental Science and Health Part B Pesticides Food Contaminants and Agricultural Wastes. 45: 128–136.

Escoffier N, Bensoussan N, Vilmin L, Flipo N, Rocher V, David A, Métivier F, Groleau A. 2018. Estimating ecosystem metabolism from continuous multi-sensor measurements in the Seine River. Environmental Science and Pollution Research. 25: 23451–23467.

Feio MJ, RQ Serra S, M Neto J. 2021. From headwaters into the estuarine zone: changes in processes and invertebrate communities in response to abiotic conditions. Aquatic Ecology. 55: 149–168. https;//

Gomi T, Sidle RC, Richardson JS. 2002. Understanding processes and downstream linkages of headwater systems. BioScience. 52: 905–916.[0905:UPADLO]2.0.CO;2

Graça MAS, Ferreira RCF, Coimbra CN. 2001. Litter processing along a stream gradient: the role of invertebrates and decomposers. Journal of the North American Benthological Society. 20: 408–420.

Grasby SE, Hutcheon I. 2000. Chemical dynamics and weathering rates of a carbonate basin Bow River, southern Alberta. Applied Geochemistry. 15: 67–77.

Han G, Liu C-Q. 2004. Water geochemistry controlled by carbonate dissolution: a study of the river waters draining karst-dominated terrain, Guizhou Province, China. Chemical Geology. 204: 1–21.

Helms JR, Stubbins A, Ritchie JD, Minor EC, Kieber DJ, Mopper K. 2008. Absorption spectral slopes and slope ratios as indicators of molecular weight, source, and photobleaching of chromophoric dissolved organic matter. Limnology and Oceanography. 53: 955–969.

Hendel B, Marxsen J. 2020. Fluorometric determination of the activity of β-glucosidase and other extracellular hydrolytic enzymes. In: Methods to Study Litter Decomposition. Cham: Springer International Publishing. p. 411–418.

Hosen JD, Aho KS, Fair JH, Kyzivat ED, Matt S, Morrison J, Stubbins A, Weber LC, Yoon B, Raymond PA. 2021. Source switching maintains dissolved organic matter chemostasis across discharge levels in a large temperate river network. Ecosystems. 24: 227–247.

Huguet A, Vacher L, Relexans S, Saubusse S, Froidefond JM, Parlanti E. 2009. Properties of fluorescent dissolved organic matter in the Gironde Estuary. Organic Geochemistry. 40: 706–719.

Kothawala DN, Murphy KR, Stedmon CA, Weyhenmeyer GA, Tranvik LJ. 2013. Inner filter correction of dissolved organic matter fluorescence. Limnology and Oceanography Methods. 11: 616–30.

Lê S, Josse J, Husson F. 2008. FactoMineR: An R package for multivariate analysis. Journal of Statistical Software. 25: 1–18.

Lupon A, Gómez-Gener L, Fork ML, Laudon H, Martí E, Lidberg W, Sponseller RA. 2023. Groundwater-stream connections shape the spatial pattern and rates of aquatic metabolism. Limnology and Oceanography Letters. 8: 350–358.

Manning P, van der Plas F, Soliveres S, Allan E, Maestre FT, Mace G, Whittingham MJ, Fischer M. 2018. Redefining ecosystem multifunctionality. Nature Ecology & Evolution. 2: 427–436.

McDonough LK, Andersen MS, Behnke MI, Rutlidge H, Oudone P, Meredith K, O'Carroll DM, Santos IR, Marjo C, Spencer RGM, et al. 2022. A new conceptual framework for the transformation of groundwater dissolved organic matter. Nature Communications. 13: 2153.

McKnight DM, Boyer EW, Westerhoff PK, Doran PT, Kulbe T, Andersen DT. 2001. Spectrofluorometric characterization of dissolved organic matter for indication of precursor organic material and aromaticity. Limnology and Oceanography. 46: 38–48.

Mejia FH, Fremier AK, Benjamin JR, Bellmor JR, Grimm AZ, Watson GA, Newsom M. 2018. Stream metabolism increases with drainage area and peaks asynchronously across a stream network. Aquatic Sciences. 81: 9.

Naiman RJ, Melillo JM, Lock MA, Ford TE, Reice SR. 1987. Longitudinal patterns of ecosystem processes and community structure in a subarctic river continuum. Ecology. 68: 1139–1156.

Ni M, Jiang S, Li S. 2020. Spectroscopic indices trace spatiotemporal variability of dissolved organic matter in a river system with Karst characteristic. Journal of Hydrology. 590: 125570.

Odum HT. 1956. Primary production in flowing waters. Limnology and Oceanography. 1: 102–117.

Ohno T. 2002. Fluorescence inner-filtering correction for determining the humification index of dissolved organic matter. Environmental Science and Technology. 36: 742–746.

Oksanen J, Blanchet FG, Friendly M, Kindt R, Legendre P, McGlinn D, O'Hara RB, Solymos P, Stevens MHH, Szoecs E, et al. 2020. vegan: community ecology package.

Operta M, Pamuk S. 2015. Geological characteristics and tectonic structure of the upper Neretva basin. Acta geographica Bosniae et Herzegovinae. 4: 63–74.

Perkins DM, Bailey RA, Dossena M, Gamfeldt L, Reiss J, Trimmer M, Woodward G. 2015. Higher biodiversity is required to sustain multiple ecosystem processes across temperature regimes. Global Change Biology. 21: 396–406.

Peter H, Ylla I, Gudasz C, Romaní AM, Sabater S, Tranvik LJ. 2011. Multifunctionality and diversity in bacterial biofilms. PloS one. 6: e23225.

Pucher M, Wünsch U, Weigelhofer G, Murphy K, Hein T, Graeber D. 2019. StaRdom: versatile software for analyzing spectroscopic data of dissolved organic matter in R. Water. 11: 2366.

R Core Team. 2022. R: A language and environment for statistical computing.

Raymond PA, Zappa CJ, Butman D, Bott TL, Potter J, Mulholland P, Laursen A, McDowell WH, Newbold D. 2012. Scaling the gas transfer velocity and hydraulic geometry in streams and small rivers. Limnology & Oceanography Fluids & Environments. 2: 41–53.

Rier ST, Shirvinski JM, Kinek KC. 2014. In situ light and phosphorus manipulations reveal potential role of biofilm algae in enhancing enzyme-mediated decomposition of organic matter in streams. Freshwater Biology. 59: 1039–51.

Rodríguez-Castillo T, Estévez E, González-Ferreras AM, Barquín J. 2019. Estimating ecosystem metabolism to entire river networks. Ecosystems. 22: 892–911.

Romaní AM, Sabater S. 1998. A stromatolitic cyanobacterial crust in a Mediterranean stream optimizes organic matter use. Aquatic Microbial Ecology. 16: 131–141.

Rugel K, Golladay SW, Jackson CR, Rasmussen TC. 2016. Delineating groundwater/surface water interaction in a karst watershed: Lower Flint River Basin, southwestern Georgia, USA. Journal of Hydrology Regional Studies. 5: 1–19.

Sabater S, Guasch H, Romaní A, Muñoz I. 2000. Stromatolitic communities in Mediterranean streams: adaptations to a changing environment. Biodiversity and Conservation. 9: 379–392.

Segatto PL, Battin TJ, Bertuzzo E. 2021. The metabolic regimes at the scale of an entire stream network unveiled through sensor data and machine learning. Ecosystems. 24: 1792–1809.

Simon KS, Pipan T, Ohno T, Culver DC. 2010. Spatial and temporal patterns in abundance and character of dissolved organic matter in two karst aquifers. Fundamental and Applied Limnology / Archiv für Hydrobiologie. 177: 81–92.

Sinsabaugh RL, Carreiro MM, Repert DA. 2002. Allocation of extracellular enzymatic activity in relation to litter composition, N deposition, and mass loss. Biogeochemistry. 60: 1–24.

Smeti E, Tsirtsis G, Skoulikidis NT. 2023. Geology can drive the diversity–ecosystem functioning relationship in river benthic diatoms by selecting for species functional traits. Biology. 12: 81.

Smith RM, Kaushal SS. 2015. Carbon cycle of an urban watershed: exports, sources, and metabolism. Biogeochemistry. 126: 173–195.

Steinman AD, Lamberti GA, Leavitt PR, Uzarski DG. 2017. Methods in stream ecology. Volume 1, Third Edition. Boston: Academic Press. Chapter 12, Biomass and Pigments of Benthic Algae; p. 223–241.

Talluto MV. 2020. WatershedTools: An R pakcage for the spatial analysis of watersheds.

Tiegs SD, Akinwole PO, Gessner MO. 2009. Litter decomposition across multiple spatial scales in stream networks. Oecologia. 161: 343–351.

Tiegs SD, Clapcott JE, Griffiths NA, Boulton AJ. 2013. A standardized cotton-strip assay for measuring organic-matter decomposition in streams. Ecological Indicators. 32: 131–139.

Vannote RL, Minshall GW, Cummins KW, Sedell JR, Cushing CE. 1980. The river continuum concept. Canadian Journal of Fisheries and Aquatic Sciences. 37: 130–137.

von Schiller D, Acuña V, Aristi I, Arroita M, Basaguren A, Bellin A, Boyero L, Butturini A, Ginebreda A, Kalogianni E, et al. 2017. River ecosystem processes: A synthesis of approaches, criteria of use and sensitivity to environmental stressors. The Science of The Total Environment. 596-597: 465-480.

von Schiller D, Martí E, Riera JL, Sabater F. 2007. Effects of nutrients and light on periphyton biomass and nitrogen uptake in Mediterranean streams with contrasting land uses. Freshwater Biology. 52: 891–906.

Wang B, Qiu X-L, Peng X, Wang F. 2018. Phytoplankton community structure and succession in karst cascade reservoirs, SW China. Inland Waters. 8: 229–238.

Weishaar JL, Aiken GR, Bergamaschi BA, Fram MS, Fujii R, Mopper K. 2003. Evaluation of specific ultraviolet absorbance as an indicator of the chemical composition and reactivity of dissolved organic carbon. Environmental Science and Technology. 37: 4702–4708.


Additional Files



How to Cite

Del Campo, R., Jechsmayr, B., Settles, V., Ströder, M., & Singer, G. (2023). Nutrient inputs shape ecosystem functioning gradients along the pristine, upper Neretva River, Bosnia and Herzegovina. Natura Sloveniae, 25(3), 239-263.

Similar Articles

1-10 of 90

You may also start an advanced similarity search for this article.

Most read articles by the same author(s)