Diversidade zooplanctônica influencia o funcionamento e estabilidade de um ecossistema de planície de inundação neotropical?
Diversity is important to the functioning and stability of ecosystems because of the security it provides against environmental fluctuations, as more species ensure that if one is lost another can replace it. This may be different in environments with stressful conditions. For zooplankton, water velocity can be a stressful agent, since the organisms that make up this community are characterized by low swimming capacity and prefer lentic environments, and these environments are more favorable to the development and growth of their populations. Zooplankton has significant importance in the trophic chain by acting as a trophic link linking primary producers and other higher trophic levels. Some of the mechanisms proposed to understand the relationship between biodiversity and ecosystem functioning are the niche complementarity and the sampling effect. Stability is understood as less temporal variability of the total biomass, and can also be maintained by these two mechanisms. Diversity measures are able to identify the mechanisms that are acting in the ecosystem. At a temporal scale, ecosystem functioning and stability relationships with diversity were evaluated using species richness, species equitability, functional richness, functional equitability, functional divergence and functional dispersion to identify which mechanisms were working, and if there were differences between lentic and lotic environments. These relationships were analyzed in 17 years (2000-2016) in 10 floodplain environments of the Upper Paraná River (five lentic and five lotic), using total biomass of zooplankton as a substitute variable for secondary productivity, and temporal variability of total zooplankton biomass for stability estimation. The ecosystem diversity-functioning relationship was maintained in both types of environments by the two mechanisms, niche complementarity and sampling effect, indicating a strong trend in the relationship. The use of different metrics made it possible to find two mechanisms by which diversity acts in the functioning of the ecosystem. It was also found that species richness positively influenced ecosystem functioning, indicating that species loss can generate significant reductions in aggregate ecosystem properties, such as total community biomass. Added to this, the lentic and lotic environments presented similar patterns, indicating a strong tendency in the relation between the diversity metrics and the functioning of the ecosystem. The diversity-stability relationship was probably maintained by interspecific competition, although there was no asynchrony among populations in lentic environments. In lotic environments, stability was generated by a community with a greater number of species that had more similar abundances, lower dominance, and the species had more similar traits, generating asynchronous population fluctuations. Studies that seek to evaluate the functioning and stability of ecosystems are necessary, especially for the conservation of ecosystems. Anthropogenic impacts are increasingly frequent, with greater magnitude, and are changing habitat characteristics, changing processes that affect the functioning and stability of ecosystems. The attention must be mainly in the tropics, where high biodiversity still persists.
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| Format: | Thesis/Dissertation biblioteca |
| Language: | Portuguese |
| Published: |
Universidade Estadual de Maringá. Departamento de Biologia. Programa de Pós-Graduação em Ecologia de Ambientes Aquáticos Continentais
2019
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| Subjects: | Zooplâncton de água doce, Comunidades, Ecologia de, Diversidade funcional, ASFA_2015::Y::Zooplankton, ASFA_2015::F::Freshwater ecology, ASFA_2015::C::Communities (ecological), ASFA_2015::D::Dispersion, ASFA_2015::F::Freshwater organisms, ASFA_2015::F::Floodplains, ASFA_2015::E::Ecological diversity, |
| Online Access: | http://hdl.handle.net/1834/15284 |
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| Summary: | Diversity is important to the functioning and stability of ecosystems because of the security it provides against environmental fluctuations, as more species ensure that if one is lost another can replace it. This may be different in environments with stressful conditions. For zooplankton, water velocity can be a stressful agent, since the organisms that make up this community are characterized by low swimming capacity and prefer lentic environments, and these environments are more favorable to the development and growth of their populations. Zooplankton has significant importance in the trophic chain by acting as a trophic link linking primary producers and other higher trophic levels. Some of the mechanisms proposed to understand the relationship between biodiversity and ecosystem functioning are the niche complementarity and the sampling effect. Stability is understood as less temporal variability of the total biomass, and can also be maintained by these two mechanisms. Diversity measures are able to identify the mechanisms that are acting in the ecosystem. At a temporal scale, ecosystem functioning and stability relationships with diversity were evaluated using species richness, species equitability, functional richness, functional equitability, functional divergence and functional dispersion to identify which mechanisms were working, and if there were differences between lentic and lotic environments. These relationships were analyzed in 17 years (2000-2016) in 10 floodplain environments of the Upper Paraná River (five lentic and five lotic), using total biomass of zooplankton as a substitute variable for secondary productivity, and temporal variability of total zooplankton biomass for stability estimation. The ecosystem diversity-functioning relationship was maintained in both types of environments by the two mechanisms, niche complementarity and sampling effect, indicating a strong trend in the relationship. The use of different metrics made it possible to find two mechanisms by which diversity acts in the functioning of the ecosystem. It was also found that species richness positively influenced ecosystem functioning, indicating that species loss can generate significant reductions in aggregate ecosystem properties, such as total community biomass. Added to this, the lentic and lotic environments presented similar patterns, indicating a strong tendency in the relation between the diversity metrics and the functioning of the ecosystem. The diversity-stability relationship was probably maintained by interspecific competition, although there was no asynchrony among populations in lentic environments. In lotic environments, stability was generated by a community with a greater number of species that had more similar abundances, lower dominance, and the species had more similar traits, generating asynchronous population fluctuations. Studies that seek to evaluate the functioning and stability of ecosystems are necessary, especially for the conservation of ecosystems. Anthropogenic impacts are increasingly frequent, with greater magnitude, and are changing habitat characteristics, changing processes that affect the functioning and stability of ecosystems. The attention must be mainly in the tropics, where high biodiversity still persists. |
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