Ecological responses of two shrimp populations (Palaemonidae) to seasonal abiotic factor variations in a Brazilian semiarid reservoir

Abstract

The objective of this study was to evaluate if seasonal abiotic factor variations (pluviosity, depth, temperature, dissolved oxygen, hydrogen potential, ammonia and electrical conductivity) in a northeastern semiarid reservoir influence abundance and population structure variations in Palaemonidae Macrobrachium amazonicum and M. jelskii shrimp. Data were collected bimonthly from 30 reservoir sampling sites from October 2016 to September 2017 during the dry and rainy seasons. A principal component analysis determined the abiotic factors that explained most of the data variations, then a multivariate permutational variance analysis showed significant differences in abiotic variables between the dry and rainy periods. The shrimp were more abundant during the dry season compared to the rainy season, and the M. amazonicum species was more abundant than the M. jelskii species across both periods. Additionally, redundancy analysis for each seasonal period indicated that seasonal abiotic factor variations caused different responses in the abundance of intrapopulation groups (females, males and juveniles) in the two studied shrimp species. The present results suggest that related shrimp species may present different responses to seasonal abiotic factor variations, suggesting these ecological differences may be crucial to ensure a stable coexistence. Moreover, high plasticity appears to provide M. amazonicum and M. jelskii a good adaptation, especially to life in reservoirs, which are unstable environments.

KEY WORDS:

• decapod
• temporal
• Macrobrachium amazonicum
• Macrobrachium jelskii
• Mid-Northeastern

ACKNOWLEDGEMENTS

The authors are grateful to the Regional University of Cariri (URCA) for granting the material and transportation used during the development of this study. We thank the Instituto Chico Mendes de Conservação da Biodiversidade (ICMBio) for providing collection permits (SISBIO/4659049). The authors would also like to thank the Companhia de Gestão de Recursos Hídricos do Ceará (COGERH/CRATO) and the regional manager Alberto Medeiros, and Antônio for their valuable help. The authors extend their thanks to the many colleagues from the Laboratório de Crustáceos do Semiárido (LACRUSE) who helped with the fieldwork and laboratory analysis. This study was partially financed by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior — Brazil (CAPES) — Finance Code 001.

DISCLOSURE STATEMENT

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior [1487749/2015-1].