Volume 44, Nº 1 - março 2023
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DOI:10.5894/rh44n1-cti1
Este artigo é parte integrante da Revista Recursos Hídricos, Vol. 44, Nº 1, 13-25, março de 2023.
A decomposição de matéria vegetal como ferramenta para avaliar a integridade funcional de rios e ribeiros – avançando para uma monitorização integrada da condição ecológica do ecossistema
Decomposition of plant matter as a tool to assess the functional integrity of streams and rivers – moving towards an integrated assessment of ecosystem ecological integrity
Verónica Ferreira1, 2*, Manuel A. S. Graça1, 3
* Autor para a correspondência: [email protected]
1 MARE – Centro de Ciências do Mar e do Ambiente, ARNET – Rede de Investigação Aquática, Departamento de Ciências da Vida, Universidade de Coimbra.
2 Investigadora Auxiliar
3 Professor Catedrático, [email protected]
RESUMO
Os rios e ribeiros prestam inúmeros serviços às populações humanas e por isso a proteção e o restauro da sua integridade ecológica devem ser objetivos societais. A integridade ecológica compreende a integridade estrutural (e.g., a composição das comunidades aquáticas e a qualidade da água) e a integridade funcional (e.g., os processos ecossistémicos). No entanto, a biomonitorização oficial de rios e ribeiros, seguindo as orientações da Diretiva Quadro da Água, baseia-se apenas em indicadores estruturais. Consequentemente, tem havido múltiplos apelos para a inclusão de indicadores funcionais na biomonitorização de rios e ribeiros.
A decomposição de matéria vegetal de origem terrestre é um processo essencialmente biológico, que é afetado direta e indiretamente (via efeitos nas comunidades aquáticas) pelas condições ambientais, e estas podem ser alteradas pelas atividades antropogénicas. O método para avaliar a decomposição de matéria vegetal é relativamente simples: implica colocar uma quantidade conhecida de matéria vegetal (e.g., folhas) em sacos de rede (permeáveis à entrada de água, microrganismos decompositores e, eventualmente, invertebrados detritívoros), incubar os sacos nos rios e ribeiros, recuperá-los após algum tempo e pesar a matéria vegetal remanescente. Os resultados são expressos como taxa de decomposição (uma medida da velocidade a que a matéria vegetal perde massa). Há várias abordagens no uso destes valores para avaliar a integridade funcional do ecossistema. Aqui vamos recorrer à evidência científica para apresentar o potencial da decomposição de matéria vegetal para ser usada como indicador da integridade funcional de rios e ribeiros com o objetivo de promover a incorporação de processos ecossistémicos em programas de biomonitorização.
Há ainda trabalho a fazer com vista à simplificação e estandardização do protocolo para aplicação a larga escala, nomeadamente a definição de condições de referência e de classes de qualidade. No entanto, para se poder avançar no desenvolvimento e utilização de um indicador baseado na decomposição de matéria vegetal em programas de biomonitorização será necessário o envolvimento das instituições com responsabilidade na implementação destes programas. A integração de um indicador da integridade funcional de rios e ribeiros nos programas de biomonitorização permitirá uma avaliação integrada da condição ecológica de rios e ribeiros, em linha com a definição de estado ecológico proposta pela Diretiva Quadro da Água.
Palavras-chave: biomonitorização; decomposição de matéria vegetal; integridade ecológica; funções ecossistémicas.
ABSTRACT
Streams and rivers provide numerous services to human populations and therefore the protection and restoration of their ecological integrity must be societal goals. Ecological integrity comprises both structural integrity (e.g., the composition of aquatic communities and water quality) and functional integrity (e.g., ecosystem processes). However, the official biomonitoring of streams and rivers, following the guidelines of the Water Framework Directive, is based solely on structural indicators. Consequently, there have been multiple calls for the inclusion of functional indicators in the biomonitoring of streams and rivers.
The decomposition of plant matter of terrestrial origin (mainly senescent leaves and woody material) is essentially a biological process, directly and indirectly affected (via effects on aquatic communities) by environmental conditions, and these can be altered by human activities. The method for assessing decomposition rates of plant matter is relatively simple: it involves enclosing a known amount of plant matter (e.g., leaves) in mesh bags (permeable to water flow, decomposing microorganisms, and, eventually, detritivore invertebrates), incubating the bags in streams and rivers, recovering them after some time, and weighing the remaining plant matter. Results are expressed as decomposition rates (a measure of the speed at which plant matter loses mass) and there are several approaches that allow these values to be used to assess the functional integrity of the ecosystem. Here we will resort to scientific evidence to present the potential of the decomposition of plant matter to be used as an indicator of the functional integrity of streams and rivers with the aim of promoting the incorporation of ecosystem processes in biomonitoring programs.
There is still work to be done to simplify and standardize the protocol for large-scale use, including the definition of reference conditions and of quality classes. However, in order to advance towards the development and use of an indicator based on the decomposition of plant matter in biomonitoring programs, it will be necessary to involve the institutions responsible for implementing such programs. The integration of an indicator of the functional integrity of streams and rivers in biomonitoring programs will allow an integrated assessment of the ecological condition of these aquatic ecosystems, in line with the definition of ecological status proposed by the Water Framework Directive.
Keywords: biomonitoring; decomposition of plant matter; ecosystem functioning; stream health
Arroita, M., Aristi, I., Flores, L., Larrañaga, A., Díez, J., Mora, J., Romaní, A.M. & Elosegi, A. (2012): The use of wooden sticks to assess stream ecosystem functioning: Comparison with leaf breakdown rates. Science of the Total Environment, 440, 115–122.
Assembleia da República (2005): Lei nº 58/2005 de 29 de dezembro de 2005. Diário da República de 29 dezembro de 2005, 249, 7280–7310.
Bastias, E., Bolivar, M., Ribot, M., Peipoch, M., Thomas, S.A., Sabater, F. & Martí, E. (2020): Spatial heterogeneity in water velocity drives leaf litter dynamics in streams. Freshwater Biology, 65, 435–445.
Bonada, N., Prat, N., Resh, V.H. & Statzner, B. (2006): Developments in aquatic insect biomonitoring: A comparative analysis of recent approaches. Annual Review of Entomology, 51, 495–523.
Brosed, M., Jabiol, J., Chauvet, E. (2022): Towards a functional assessment of stream integrity: A first large-scale application using leaf litter decomposition. Ecological Indicators, 143, 109403.
Bunn, S.E., Abal, E.G., Smith, M.J., Choy, S.C., Fellows, C.S., Harch, B.D., Kennard, M.J. & Sheldon, F. (2010): Integration of science and monitoring of river ecosystem health to guide investments in catchment protection and rehabilitation. Freshwater Biology, 55, 223–240.
Canhoto, C. & Graça, M.A.S. (1996): Decomposition of Eucalyptus globulus leaves and three native leaf species (Alnus glutinosa, Castanea sativa and Quercus faginea) in a Portuguese low order stream. Hydrobiologia, 333, 79–85.
Castela, J., Ferreira, V. & Graça, M.A.S. (2008): Evaluation of stream ecological integrity using litter decomposition and benthic invertebrates. Environmental Pollution, 15, 440–449.
Colas, F., Baudoin, J.M., Gob, F., Tamisier, V., Valette, L., Kreutzenberger, K., Lambrigot, D. & Chauvet, E. (2017): Scale dependency in the hydromorphological control of a stream ecosystem functioning. Water Resources, 115, 60–73.
Comissão Europeia (2000): Directiva 2000/60/CE do Parlamento Europeu e do Concelho de 23 de outubro de 2000, que estabelece um Quadro de Acção Comunitária no Domínio da Política da Água. Jornal Oficial Comunidades Europeias de 22 dezembro de 2000, 327, 1–72.
Cornut, J., Elger, A., Lambrigot, D., Marmonier, P. & Chauvet, E. (2010): Early stages of leaf decomposition are mediated by aquatic fungi in the hyporheic zone of woodland streams. Freshwater Biology, 55, 2541–2556.
Encalada, A.C., Calles, J., Ferreira, V., Canhoto, C. M. & Graça, M.A.S. (2010): Riparian land use and the relationship between the benthos and litter decomposition in tropical montane streams. Freshwater Biology, 55, 1719–1733.
Feio, M.J., Alves, T., Boavida, M., Medeiros, A. & Graça, M.A.S. (2010): Functional indicators of stream health: A river‐basin approach. Freshwater Biology, 55, 1050–1065.
Feio, M.J., Hughes, R.M., Serra, S.R., Nichols, S.J., Kefford, B.J., Lintermans, M., Robinson, W., Odume, O.N., Calisto, M., Macedo, D.R., Harding, J.S., Yates, A.G., Monk, W., Nakamura, K., Mori, T., Sueyoshi, M., Mercado-Silva, N., Chen, K., Baek, M.J., Bae, Y.J., Tachamo-Shah, R.D., Shah, D.N., Campbell, I., Moya, N., Arimoro, F.O., Keke, U.N., Martins, R.T., Alves, C.B.M., Pompeu, P.S. & Sharma, S. (2023): Fish and macroinvertebrate assemblages reveal extensive degradation of the world’s rivers. Global Change Biology, 9, 355–374.
Ferreira, V., Albariño, R., Larrañaga, A., LeRoy, C.J., Masese, F.O. & Moretti, M. (2023): Ecosystem services provided by small streams – An overview. Hydrobiologia, 850, 2501–2535.
Ferreira, V., Canhoto, C., Pascoal, C. & Graça, M.A.S. (2019): Capítulo 12. Processos ecológicos e serviços. In: Feio M.J. & Ferreira V. (2019): Rios de Portugal. Comunidades, Processos e alterações. Imprensa da Universidade de Coimbra, Coimbra, 281–312.
Ferreira, V., Castela, J., Rosa, P., Tonin, A.M., Boyero, L. & Graça, M.A.S. (2016a): Aquatic hyphomycetes, benthic macroinvertebrates and leaf litter decomposition in streams naturally differing in riparian vegetation. Aquatic Ecology, 50, 711–725.
Ferreira, V., Elosegi, A., Tiegs, S., von Schiller, D. & Young, R. (2020): Organic-matter decomposition and ecosystem metabolism as tools to assess the functional integrity of streams and rivers – a systematic review. Water, 12, 3523.
Ferreira, V., Graça, M. A. S., de Lima, J. L. M. P. & Gomes, R. (2006): Role of physical fragmentation and invertebrate activity in the breakdown rate of leaves. Archiv für Hydrobiologie, 165, 493–513.
Ferreira, V. & Guérold, F. (2017): Leaf litter decomposition as a bioassessment tool of acidification effects in streams: Evidence from a field study and meta-analysis. Ecological Indicators, 79, 382–390.
Ferreira, V., Koricheva, J., Pozo, J. & Graça, M.A.S. (2016b): A meta-analysis on the effects of changes in the composition of native forests on litter decomposition in streams. Forest Ecology and Management, 364, 27–38.
Ferreira, V., Larrañaga, A., Gulis, V., Basaguren, A., Elosegi, A., Graça, M.A.S., & Pozo, J. (2015): The effects of eucalypt plantations on plant litter decomposition and macroinvertebrate communities in Iberian streams. Forest Ecology and Management, 335, 129–138.
Ferreira, V., Raposeiro, P.M., Pereira, A., Cruz, A.M., Costa, A.C., Graça, M.A.S. & Gonçalves, V. (2016c): Leaf litter decomposition in remote oceanic island streams is driven by microbes and depends on litter quality and environmental conditions. Freshwater Biology, 61, 783–799.
Ferreira, V., Silva, J., Cornut, J., Sobral, O., Bachele,t Q., Bouquerel, J. & Danger, M. (2021): Organic-matter decomposition as a bioassessment tool of stream functioning: A comparison of eight decomposition-based indicators exposed to different environmental changes. Environmental Pollution, 290, 118111.
Gessner, M.O. & Chauvet, E. (2002): A case for using litter breakdown to assess functional stream integrity. Ecological Applications, 12, 498–510.
Graça, M.A.S., Ferreira, R.C.F., & Coimbra, C.N. (2001): Litter processing along a stream gradient: The role of invertebrates and decomposers. Journal of the North American Benthological Society, 2, 408–420.
Gulis, V., Ferreira, V. & Graça, M.A.S. (2006): Stimulation of leaf litter decomposition and associated fungi and invertebrates by moderate eutrophication: Implications for stream assessment. Freshwater Biology, 51, 1655–1669.
Heard, S.B., Schultz, G.A., Ogden, C. B. & Griesel, T.C. (1999): Mechanical abrasion and organic matter processing in an Iowa stream. Hydrobiologia, 400, 179–186.
Hieber, M. & Gessner, M.O. (2002): Contribution of stream detritivores, fungi, and bacteria to leaf breakdown based on biomass estimates. Ecology, 83, 1026–1038.
Jabiol, J., Lecerf, A., Lamothe, S., Gessner, M.O. & Chauvet, E. (2019): Litter quality modulates effects of dissolved nitrogen on leaf decomposition by stream microbial communities. Microbial Ecology, 77, 959–966.
Larrañaga, A., Basaguren, A., Elosegi, A. & Pozo, J. (2009): Impacts of Eucalyptus globulus plantations on Atlantic streams: Changes in invertebrate density and shredder traits. Fundamental and Applied Limnology, 175, 151.
Lecerf, A. & Chauvet, E. (2008): Intraspecific variability in leaf traits strongly affects alder leaf decomposition in a stream. Basic and Applied Ecology, 9, 598–605.
Marks, J.C. (2019): Revisiting the fates of dead leaves that fall into streams. Annual Review of Ecology, Evolution, and Systematics, 50, 547–568.
McKie, B.G. & Malmqvist, B. (2009): Assessing ecosystem functioning in streams affected by forest management: Increased leaf decomposition occurs without changes to the composition of benthic assemblages. Freshwater Biology, 54, 2086–2100.
Millennium Ecosystem Assessment (2005): Ecosystems and Human Well-being: Synthesis. Island Press, Washington D.C.
Palmer, M.A. & Febria, C.M. (2012): The heartbeat of ecosystems. Science, 336, 1393–1394.
Tiegs, S.D., Clapcott, J.E., Griffths, N.A. & Boulton, A.J. (2013): A standardized cotton-strip assay for measuring organic-matter decomposition in streams. Ecological Indicators, 32, 131–139.
Verdonschot, P.F.M., van der Lee, G.H. & Verdonschot, R.C.M (2020): Integrating measures of ecosystem structure and function to improve assessments of stream integrity. Freshwater Sciences, 39, 601–604.
Shiklomanov, I. (2013): World fresh water resources. In: Gleick, P.H. (1993): Water in Crisis: A Guide to the World’s Fresh Water Resources. Oxford University Press, New York, Oxford, 13–24.
von Schiller, D., Acuña, V., Aristi, I., Arroita, M., Basaguren, A., Bellin, A., Boyero, L., Butturini, A., Ginebreda, A., Kalogianni, E., Larrañaga, A., Majone, B., Martínez, A., Monroy, S., Muñoz, I., Paunovic, M., Pereda, O., Petrovic, M., Pozo, J., Rodríguez-Mozaz, S., Rivas, D., Sabater, S., Sabater, F., Skoulikidis, N., Solagaistua, L., Vardakas, L. & Elosegi, A. (2017): River ecosystem processes: A synthesis of approaches, criteria of use and sensitivity to environmental stressors. Science of the Total Environment, 596, 465–480.
Woodward, G., Gessner, M.O., Giller, P.S., Gulis, V., Hladyz, S., Lecerf, A., Malmqvist, B., McKie, B.G., Tiegs, S.D., Cariss, H., Dobson, M., Elosegi, A., Ferreira, V., Graça, M.A.S., Fleituch, T., Lacoursière, J., Nistorescu, M., Pozo, J., Risnoveanu, G., Schindler, M., Vadineanu, A., Vought, L.B.-M. & Chauvet, E. (2012): Continental-scale effects of nutrient pollution on stream ecosystem functioning. Science, 336, 1438–1440.