The ghost of the past anthropogenic impact: Reef-decapods as bioindicators of threatened marine ecosystems

• Published in: Ecological indicators Vol. 133; p. 108465
• Main Authors: Welter Giraldes, Bruno, Alves Coelho, Petrônio, Alves Coelho Filho, Petrônio, Macedo, Thais P., Santarosa Freire, Andrea
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.12.2021; Elsevier
• Subjects: Anthropogenic impacts; Marine biology; Marine ecology; Marine protected areas; Taxonomy; Trophic chain; Anthropogenic impacts; Trophic chain; Marine biology; Marine ecology; Marine protected areas; Taxonomy
• ISSN: 1470-160X; 1872-7034
• DOI: 10.1016/j.ecolind.2021.108465

•Anthropogenic activity is molding the population of reef decapods.•Target fishing-decapods has a population reduction on threatened sites.•Small dominant decapods “prey-for-fishes” increase on threatened sites.•Decapods associated to pristine benthic coverage decrease on threatened sites.•Reef decapods can illustrate the Past anthropogenetic pressure on reef sites. This study demonstrated the plasticity of reef-decapod according with the exposed anthropogenic pressure. Comparing the reef-decapods at sites with different anthropogenic pressures in two different ecoregions (tropical and subtropical reef ecotypes), we demonstrated that historical anthropogenic activity is molding directly and indirectly their population. A direct impact over target decapods for fishing (e.g. Lobsters and large crabs) that are removed directly by human activities. A positive indirect impact related to a top-down trophic imbalance with the increase of naturally dominant preys (small decapod) due to the removal of top predators. Thus, insufficient predators to control the abundant prey in a classic unbalanced prey-predator relationship. An indirect and negative impact, related to a bottom-up trophic imbalance, is the exclusion of niche-restricted species in association with benthic cover (e.g. corals). This also has the positive outcome, however, of increasing numbers of herbivores, detritivores and scavengers. As hypothesis, we propose that a current biodiversity balance in anthropogenically impacted ecosystem is just reflecting past trophic cascade events. Where the remaining biodiversity is monopolizing the vacant niches after the removal of components in a trophic chain. Therefore, we are suggesting that reef-decapod biodiversity, observed using visual identification, can be used to highlight the “Ghost of the past anthropogenic impact” in threatened ecosystems.