Publicação
Use and persistence of empty bivalve shells
| Resumo: | Freshwater bivalves are remarkable organisms that can potentially influence biological communities through their engineering attributes, such as their hard shells. Bivalve shells can contribute to important physical modifications that can alter the structure of aquatic benthic communities. One of the most successful invasive species worldwide is the Asian clam Corbicula fluminea, it can cause severe ecological and economic impacts. Minho River is a highly invaded area by the species, currently representing more than 90% of the benthic biomass. Little is known about the effects that shells of different bivalve species, with different morphologies, and origins have on the associated fauna, and for how long they can persist in the freshwater systems. Given that, the objectives of the present study were, to assess the effect of shells of different bivalve species on the macrozoobenthic fauna, and to determine the shell decay rates of the different bivalve species, considering the influence of the size, river condition (lentic versus lotic) and season. For the experiments, shells of native (Anodonta anatina, Potomida littoralis and Unio delphinus) and one invasive (Corbicula fluminea) bivalve species were used. The study results suggest that substrate heterogeneity may play an important role in attracting the macrozoobenthic fauna, as the heterogeneous treatments (the ones that had more than one bivalve species) were associated with more abundant, rich and diverse macrozoobenthic community than the homogeneous treatments, although significant differences were only found for abundance. Furthermore, shell decays varied among species, season, river condition and shell size. Anodonta anatina was the species that exhibited the highest percentage of decay during the four seasons, followed by U. delphinus, C. fluminea and P. littoralis. Also, shells decayed around 50% faster under lotic than under lentic conditions, and the size of the shells also influenced the decay rates. The results of the present study suggest that the structures formed with two species of bivalve shells support significantly more abundant macrozoobenthic communities, and that the shell size, season and river condition associated to other factors (i.e. leaf deposition and agglomerations of shells) can have major influence on the shell decays. |
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| Autores principais: | Amorim, Luís Carlos da Silva |
| Assunto: | Ciências Naturais::Ciências Biológicas |
| Ano: | 2016 |
| País: | Portugal |
| Tipo de documento: | dissertação de mestrado |
| Tipo de acesso: | acesso aberto |
| Instituição associada: | Universidade do Minho |
| Idioma: | inglês |
| Origem: | RepositóriUM - Universidade do Minho |
| Resumo: | Freshwater bivalves are remarkable organisms that can potentially influence biological communities through their engineering attributes, such as their hard shells. Bivalve shells can contribute to important physical modifications that can alter the structure of aquatic benthic communities. One of the most successful invasive species worldwide is the Asian clam Corbicula fluminea, it can cause severe ecological and economic impacts. Minho River is a highly invaded area by the species, currently representing more than 90% of the benthic biomass. Little is known about the effects that shells of different bivalve species, with different morphologies, and origins have on the associated fauna, and for how long they can persist in the freshwater systems. Given that, the objectives of the present study were, to assess the effect of shells of different bivalve species on the macrozoobenthic fauna, and to determine the shell decay rates of the different bivalve species, considering the influence of the size, river condition (lentic versus lotic) and season. For the experiments, shells of native (Anodonta anatina, Potomida littoralis and Unio delphinus) and one invasive (Corbicula fluminea) bivalve species were used. The study results suggest that substrate heterogeneity may play an important role in attracting the macrozoobenthic fauna, as the heterogeneous treatments (the ones that had more than one bivalve species) were associated with more abundant, rich and diverse macrozoobenthic community than the homogeneous treatments, although significant differences were only found for abundance. Furthermore, shell decays varied among species, season, river condition and shell size. Anodonta anatina was the species that exhibited the highest percentage of decay during the four seasons, followed by U. delphinus, C. fluminea and P. littoralis. Also, shells decayed around 50% faster under lotic than under lentic conditions, and the size of the shells also influenced the decay rates. The results of the present study suggest that the structures formed with two species of bivalve shells support significantly more abundant macrozoobenthic communities, and that the shell size, season and river condition associated to other factors (i.e. leaf deposition and agglomerations of shells) can have major influence on the shell decays. |
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