Physical habitat condition as a key tool to maintain freshwater biodiversity in neotropical artificial ponds

In areas highly affected by anthropogenic disturbances,artificial(human-made)freshwater ecosystems can provide habitat for maintaining and conserving regional freshwater biodiversity.We assessed how the physical habitat of artificial ponds affected the structure of benthic macroinvertebrate assemblages.To do so,we tested two hypotheses.(1)Physical habitat disturbances are not detrimental to the diversity of nearby artificial ponds,and(2)Physical habitat disturbances do not cause significant shifts in taxonomic composition.Our results rejected both null hypotheses,i.e.,macroinvertebrate diversity metrics correlated significantly and positively with Physical Habitat Integrity index scores,and only sites with high habitat condition scores were significantly associated with sensitive indicator taxa.Our results highlight the importance of maintaining physical habitat conditions for sustaining the ecological health of artificial ponds.

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.

What physical habitat factors determine the distribution of gastropods in neotropical headwater streams?

Freshwater gastropods play a pivotal role in the structure and functioning of freshwater ecosystems,but despite their importance,there are still gaps in their ecology.Our goal was to understand what physical habitat factors are the most important for the distribution of freshwater gastropods in headwater stream ecosystems in the Neotropical Savanna and provide a baseline for conservation and management efforts for freshwater gastropods in this biome.We identified five taxa,each with different environmental prefferences.Littoridina presence related negatively with stream slope,Biomphalaria presence related positively with total dissolved solids and the proportions of cobble,fine sediment and organic matter.Gundlachia presence correlated positively with elevation and the proportion of pools in the site.Physa presence related negatively with total dissolved solids and positively with alkalinity.Melanoides tuberculata presence correlated positively with the proportion of coarse gravel.Our results highlight the challenge for protecting native freshwater gastropod assemblages(and managing non-native invasive species),because environmental preferences vary widely amongst taxa and most are vulnerable to common anthropogenic disturbances.