Thermodynamic based indicators illustrate how a run-of-river impoundment in neotropical savanna attracts invasive species and alters the benthic macroinvertebrate assemblages’ complexity

2019 ◽

Keyword(s):

Land Use ◽

Anthropogenic Disturbances ◽

Benthic Macroinvertebrate ◽

Tolerance Index ◽

Neotropical Savanna ◽

Macroinvertebrate Assemblages ◽

Future Challenges ◽

Freshwater Habitats ◽

Landscape Scales ◽

The Many

<i>Abstract.</i>—Despite its importance as a global biodiversity hotspot, the Neotropical savanna is threatened by rampant agricultural, hydropower, and mining development. This chapter describes the influence of landscape patterns and land uses on the taxonomic composition and structure of benthic macroinvertebrate assemblages in wadeable streams and hydropower reservoirs in the Neotropical savanna, southeastern Brazil. We used the following approaches: (1) an environmental fragility (erodibility) index, (2) an integrated disturbance index, (3) a hemeroby index of natural vegetation change, (4) the spatial distribution of benthic macroinvertebrate assemblages, (5) macroinvertebrate multimetric indices, and (6) a simplified macroinvertebrate tolerance index for urban streams. We found that land use and anthropogenic disturbances at the catchment scale had significant effects on the structure and functioning of lotic ecosystems, thereby reducing their ability to deliver ecosystem services. Our results also showed that citizen science projects can successfully apply simple, inexpensive methodologies and open an important dialogue between academia and the society at large. This chapter is a synthesis of multistatus and multispatial scale assessment of landscape effects on benthic macroinvertebrates living in headwaters and hydropower dam reservoirs in the Neotropical savanna. Future challenges include incorporating novel ecological methodologies in ecological syntheses (e.g., eco-bioinformatics), functional trait-based indices and holistic thermodynamic indices, and standardized assessment methodologies. Doing so will further our understanding of the many-layered ecological effects of land use and other anthropogenic disturbances on aquatic biota at landscape scales.

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Habitat formed by the invasive macroalga Caulerpa filiformis (Suhr) Hering (Caulerpales, Chlorophyta) alters benthic macroinvertebrate assemblages in Peru

10.21203/rs.3.rs-1001759/v1 ◽

2021 ◽

Author(s):

Silvia Aguilar ◽

Pippa J. Moore ◽

Roberto A. Uribe

Keyword(s):

Invasive Species ◽

Benthic Macroinvertebrates ◽

Ecological Impact ◽

Ecological Impacts ◽

Benthic Macroinvertebrate ◽

Soft Sediment ◽

Taxonomic Richness ◽

Macroinvertebrate Assemblages ◽

Peruvian Coast ◽

The Impact

Abstract The green macroalga Caulerpa filiformis has been spreading on shallow soft sediment habitats along the Peruvian coast, colonizing previously unvegetated sediments to create monospecific meadows. We examined the nature of the impact of C. filiformis meadows on the density, taxonomic richness and assemblage structure of epifaunal and infaunal benthic macroinvertebrates. Specifically, we tested whether the spread of C. filiformis has resulted in different macroinvertebrate assemblages than those formed by the dominant native macroalgae (i.e., Rhodymenia spp.) and unvegetated sediments. Surveys were undertaken in two bays in each of two locations, in central and southern Peru, during winter 2017 and summer 2018. In general, our results show that macroinvertebrate assemblages were similar across all three habitats, although there were some differences, related to location and season, but with no clear patterns observed. Taxonomic richness and density was generally higher in the vegetated habitats than the unvegetated habitat, and where there were differences between the two vegetated habitats there was no consistent pattern of which habitat supported the highest richness or density. Given invading C. filiformis is primarily colonizing unvegetated habitats it would appear that this species is creating a new niche which supports similar assemblages, but higher taxonomic richness and density than unvegetated habitats. While our study suggests that C. filiformis is having a limited ecological impact we recommend that actions be put in place to limit the spread of this invasive species at the same time as increasing monitoring of the ecological impacts of this species as lags in the ecological impacts of invasive species are common.

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