Mine tailings storage dams modify upstream headwater fish assemblages

Riverscape connectivity is a critically important component determining the ecological condition of lotic ecosystems.We evaluated changes in fish assemblages caused by the loss of connectivity by mine tailings storage dams(TSDs),hypothesizing that headwater fish assemblages are restructured by TSDs located downstream,even though the upstream habitats are not altered.We used standard methods to collect fish in 24 first to third order sites,with half draining to TSDs(dammed)and the other half free from this impact(undammed).To identify differences between treatments,we used PERMANOVA to test both environmental variables and ichthyofauna composition(Bray-Curtis similarity index)and evaluated the biological metrics that most influenced assemblage composition change.As expected,we observed no difference between treatments for environmental variables,but we did observe differences in fish assemblage composition.We also observed five metrics with lower values in dammed streams(richness and abundance of intolerant species,siluriform richness,and abundance of Pareiorhaphis cf.proskynita and Trichomycterus brasiliensis)and two metrics with higher values in dammed streams(perciform richness and abundance of Oligosarcus argenteus).We believe these changes resulted from of stream fragmentation by TSDs,in addition to source-sink mechanisms and conclude that mine TSDs located downstream change headwater fish assemblages,an impact often neglected in biomonitoring and bioassessment studies.

Tropical and subtropical streams:A synthesis

Tropical and sub-tropical streams harbor great biodiversity and are responsible for crucial ecosystem services.Intending to contribute to the understanding of how anthropogenic stressors and pressures alter functional or taxonomic diversity in biotic assemblages or processes in these systems,Water Biology and Security published eight papers.The research originated from Cameroon(Central Africa),southeastern Brazil,eastern Amazonia,and eastern China,representing eight river basins:Huai,Sui and Yishusi from east Asia;São Francisco,Doce,Jequitinhonha,and Amazon from South America;and Congo from Africa.The last two are the most biodiverse on the planet.The studied biomes included tropical rainforest and savanna,neotropical savanna and rainforest,neotropical savanna mountains,and subtropical monsoon forest.The response variables included fish assemblages(3 papers),entire macroinvertebrate assemblages or sub-groups(4 papers),and stream physical habitat structure(1 paper).

Global concerns related to water biology and security:The need for language and policies that safeguard living resources versus those that dilute scientific knowledge

Increasingly,scientists and non-scientists,especially employees of government agencies,tend to use weak or equivocal language when making statements related to science policy and governmental regulation.We use recent publications to provide examples of vague language versus examples of strong language when authors write about regulating anthropogenic pressures on natural resources.Lifeless language is common in agency reports,policy documents,and even scientific papers published by academics.Such language limits success in regulating anthropogenic pressures on natural resources.This challenge must be recognized and countered as a driver of the condition of water and associated resources.We also list sources of vague wording,provide global examples of how ambiguous language and political influences have contributed to water resource degradation,discuss the recent history of science censorship,and offer possible solutions for more direct scientific discourse.We found that:(1)equivocal language was especially common in concluding statements and not only by government employees;(2)authors discussed confusing language concerns in an agency publication;and(3)agency employees sometimes used active,strong language.Key drivers of weak language include:(1)holding on to old paradigms and resisting new knowledge;(2)scientific uncertainty;(3)institutional manuscript review policies;(4)employment and funding insecurity;and(5)avoiding the appearance of advocacy.Examples associated with euphemistic language included climate change,flow and physical habitat alteration,dams,agriculture,mining,forestry,and fisheries,as well as resistance towards monitoring,assessing,and reporting ecological conditions.Suggestions for mitigating equivocal language involve employment protections and greater focus on scientific ethics.We conclude that natural resource scientists should resist calls to employ imprecise language.Instead,they should be strong advocates for prescriptive and protective natural resource actions—based on their science—to halt and reverse the systemic degradation of those resources.

Which metrics drive macroinvertebrate drift in neotropical sky island streams?

Despite long-standing interest,the mechanisms driving aquatic macroinvertebrate drift in tropical streams remain poorly understood.Therefore,the objective of this study was to evaluate which environmental metrics drive macroinvertebrate drift in neotropical sky island streams.We evaluated whether altitude,the abundance of food resources,and variations in water quality influenced macroinvertebrate drift density,diversity,richness,and functional feeding groups.An hypothesis was developed to test whether increased altitude,lower food availability(particulate organic matter),and discharge would increase the density,taxonomic richness,and diversity of drifting invertebrates.Nine headwater stream sites were sampled in the rainy and dry seasons in the Espinhaço Meridional Mountain Range(EMMR)of southeast Brazil.Samples were collected using drift nets deployed from 5:00 p.m.to 8:00 p.m.The abundance of food resources was assessed through estimates of coarse(CPOM)and fine(FPOM)particulate organic matter,and primary producers.CPOM availability was an important explanatory variable for Gathering-Collectors and Scrapers,Altitude was important for Shredders and Predators,and Filtering-Collectors were linked to water discharge,suggesting that functional group drift masses were linked to different ecosystem components.Water temperature,conductivity,dissolved oxygen,current velocity,FPOM biomass and microbasin elevation range exerted little influence on macroinvertebrate drift.Regarding taxa composition,this study also found that Baetidae and Leptohyphidae(Ephemeroptera)and Chironomidae and Simuliidae(Diptera)were the most abundant groups drifting.

Assemblage-based biomonitoring of freshwater ecosystem health via multimetric indices:A critical review and suggestions for improving their applicability

Freshwater biota are more comprehensive and direct indicators of biological impacts,and more meaningful to the public than water quality or physical habitat surrogates.Freshwater biotic data and the multiple biological indicators developed from them offer a much richer array of data for assessing the impacts of pollution controls than a limited set of physical or chemical measures.In recent decades,assemblage-based assessments by ecologists,environmental scientists,and water quality agencies have been employed globally for determining the condition of,and threats to,freshwater ecosystems.A key step in this advance has been the development of multimetric indices(MMIs)or indices of biotic integrity(IBIs)based on quantitative assessments of algae,macrophyte,macroinvertebrate,fish or riparian bird assemblages.In Europe,where biological assemblages are mandated for assessing freshwater ecosystem health,many indices are multimetric.However,the proliferation of MMIs globally has not always occurred through the application of rigorous study designs and monitoring protocols,nor have they always effectively incorporated functional metrics,stressor assessments,and statistical analyses.Therefore,in this review,we discuss eleven major concerns with the development and application(including logistical limitations)of multimetric indicators based on freshwater biota to encourage more rigorous and widely applicable(transferable)MMI use and implementation.Specifically,our concerns focus on reference conditions;sampling effort,methods,and season;trophic guild definition;metric comprehensiveness,options,screening and scoring;and MMI validation.MMIs could also benefit from increased attention to ecological mechanisms and metric development,to further improve our understanding of anthropogenic impacts as well as rehabilitation effects on freshwater ecosystems globally.Paying closer attention to study designs,ecological mechanisms and metric development should further improve our understanding of anthropogenic impacts and better facilitate rehabilitation of degraded freshwater ecosystems,as well as aiding in the conservation of healthy freshwater ecosystems globally.

Water Biology and Security-A new open-access platform for multidisciplinary research concerning freshwater and marine ecosystems

1.Why Water Biology and Security?Water is an essential natural resource for human survival and development,by providing ecosystem services(drinking water,aquatic foods,transportation,hydropower,biodiversity support).Globally,aquatic foods provide more than 20%of the animal protein for the world's human population,with this percentage reaching 50%in some developing countries(FAO,2020).Aquaculture has been transformed from a farming practice into a modern industry with important contributions to global food security(Gui et al.,2018;Naylor et al.,2021;Golden et al.,2021).

A review of potential conservation and fisheries benefits of breaching four dams in the Lower Snake River(Washington,USA)

Abundances of important and imperiled fishes of the Snake River Basin continue to decline.We assessed the rationale for breaching the four lower Snake River Basin dams to prevent complete loss of these fishes,and to maximize their likelihood of recovery.We summarize the science surrounding Sockeye Salmon(Oncorhynchus nerka),Chinook Salmon(O.tshawytscha),steelhead(O.mykiss),Bull Trout(Salvelinus confluentus),White Sturgeon(Acipenser transmontanus),and Pacific Lamprey(Entosphenus tridentatus).From this,we drew ten conclusions:(1)development of the Columbia River System(including the Snake River Basin)has converted mainstem rivers into reservoirs,altering fish behavior and survival;(2)most populations currently record their lowest abundance;(3)the Columbia River System dams reduce productivity of diadromous fishes in the highest-quality spawning grounds that could buffer against future climate dynamics;(4)past actions have done little to reduce impacts or precipitate recovery;(5)the Columbia River System constrains survival and productivity of salmon,steelhead and Bull Trout;(6)Snake River Basin salmon and steelhead remain at high extinction risk;(7)eliminating migration impediments and improving mainstem habitats are essential for maintaining genetic diversity and improving Bull Trout persistence;(8)the lower Snake River Basin dams preclude passage of adult White Sturgeon,constraining gene flow and recruitment;(9)the lower Snake River Basin dams impede dramatically passage of adult and juvenile Pacific Lamprey,and(10)Snake River Basin Pacific Lamprey is at high risk of extirpation.Breaching the four lower Snake River Basin dams is an action likely to prevent extirpation and extinction of these fishes.Lessons from the Columbia River System can inform conservation in other impounded rivers.