The studies on bromeliad fauna are spread more and more, not just due importance in the knowledge about animal diversity, but mainly thanks to the active ecological dynamics in these systems, since their basic rules could be applied in more complex systems. The leaves of most of the bromeliad species are arranged in way spiraled in a rosette, forming a cistern, or hit, which accumulates water of the rain, sediments of the dossel and other countless detritus. The decomposition of this debris contains many nutritious, which they are used not just by the bromeliad, through the located tricomas in their leaves, but also for other several organisms that participate in these intricate relationships. During this research 24 bromeliads of Vriesea friburgensis were collected, in elapsing of one year, and examined in search of macroscopic organisms, which were fastened in alcohol 70th and identified. These organisms were divided in seven classes, 20 orders and 50 families. The highlighted classes were Insecta and Arachnida. The most abundant orders were Coleoptera (45.3%), Hymenoptera (23.5%), Aranea (11.0%) and Diptera (9.7%); in keeping with result other similar works. Several ecological groups, or guilds, were established with base in the literature and field observations, looking for to increase the knowledge about the polytrophic relationships presented in this personal micro-universe. About 90% of total collected organisms belong to 15 families, and the three most found were Hydrophilidae (37.7%), Formicidae (23.5%) e Hahnidae (5.4%), witch ones were responsible for 67% of relative abundance on the community. The families with higher indices of relative frequency were Hydrophilidae (62.5%), Hahnidae (58.3%) e Formicidae (54.2%). The epiphytes bromeliads are different of the ground ones, some animals prefer one or another, the epiphytes have less biodiversity (H : 1,818) than the ground ones (H : 2,923). In the autumn were found the higher number of individuals (412), followed by winter (226), spring (226) and summer (190). The family richness were high on autumn (37), followed by winter (29), summer (27) and spring (18). This ecosystem can or could be a model and an example of polytrophic relationships, the systematic should use this diversity and help to identify the species witch depend of bromeliads to life. / Os estudos sobre fauna bromeliolícola são cada vez mais difundidos, não apenas devido a sua importância no conhecimento sobre a diversidade animal, mas principalmente graças à dinâmica ecológica atuante nestes sistemas, já que suas regras básicas poderiam ser aplicadas em sistemas mais complexos. As folhas da maioria das espécies de bromélias são arranjadas de maneira espiralada em uma roseta, formando uma cisterna, ou tanque, a qual acumula água da chuva, sedimentos do dossel e inúmeros outros detritos. A decomposição destes detritos contém muitos nutrientes, os quais são utilizados não apenas pela bromélia, através dos tricomas, localizados em suas folhas, mas também por diversos outros organismos que participam destas intricadas relações. Durante esta pesquisa foram coletadas 24 bromélias, 12 epífitas, 12 de solo, da espécie Vriesea friburgensis, no decorrer de um ano, e examinadas em busca de organismos macroscópicos, os quais foram fixados em álcool 70% e identificados. Estes organismos estão distribuídos em sete classes, 20 ordens e 50 famílias. As classes que se destacaram foram Insecta e Arachnida. As ordens mais abundantes foram Coleoptera (45,3%), Hymenoptera (23,5%), Aranea (11,0%) e Diptera (9,7%). Do total de organismos coletados, 90% estão compreendidos em 15 famílias e, destas, as três mais observadas foram Hydrophilidae (37,7%), Formicidae (23,5%) e Hahnidae (5,4%), as quais compreendem 67% da abundância relativa na comunidade. As famílias que apresentaram o maior índice de freqüência relativa foram Hydrophilidae (62,5%), Hahnidae (58,3%) e Formicidae (54,2%). Foi constatado que bromélias epífitas diferem das de solo, e que certos organismos possuem preferências por uma ou por outra, além de que as bromélias epífitas apresentaram menor biodiversidade (H : 1,818) em relação aquelas caídas ao solo (H : 2,923). Durante o outono foi encontrado o maior número de organismos (412), seguido pelo inverno (226), primavera (226) e verão (190). A riqueza de famílias foi maior durante o outono (37), seguida do inverno (29), verão (27) e primavera (18). A utilização deste ecossistema como modelo e exemplo de relações politróficas é fato concreto e, cabe à sistemática aproveitar esta diversidade para elucidar com clareza quais espécies dependem, exclusivamente, das bromélias para realizar seus ciclos vitais.

Sediments from four areas adjacent to marinas and a background site in the Intracoastal Waterway were assessed for macroinvertebrate composition and heavy metal contamination. Sediment core samples were collected in 2004 and 2005 for analyses of macroinvertebrate composition and sediment grain size. Additional sediment samples were collected in 2005 for chemical analyses of metals (Al, As, Cd, Cr, Cu, Fe, Pb, Hg, Ni and Zn). MANOVA and dendograms using Bray-Curtis similarity matrices grouped the sites into two clusters: the 3 sites closest to the New River formed one group, and the two end sites formed the other. The sites nearest the New River were dominated by polychaetes, half of which were pollutant-tolerant species (e.g., Capitella capitata). The macroinvertebrate communities of the two end sites were dominated by tanaids, gastropods and sipunculids with fewer annelids than the other 3 sites. The influence of the New River on the study sites appeared to outweigh the sources of metal pollution found in marinas. The 3 sites closest to the New River had higher metal concentrations than the two end sites. The background site, nearest the mouth of the New River, exceeded the Florida sediment quality guideline probable effect level for cadmium and copper while three of the four marina sites exceeded at most one probable effect level and one or more threshold effect levels for cadmium and copper. The furthest site from the New River, which was the closest site to Port Everglades, had the lowest metal concentrations. Additional studies are needed to determine the level of pollutant loading from the New River and its effects on nearby biological communities.

Permafrost thaw slumping along lakeshores in lakes of the Mackenzie Delta Uplands, NT is known to alter water chemistry significantly. Its impact on benthic communities and persistent organic pollutant (POP) behaviour in lakes is not known. Benthic invertebrate communities responded to slumps through changes to community composition and size spectra. Larger taxa tended to dominate in lakes with slumps. Variability in biomass size spectra was related to total dissolved nitrogen concentration and slump size. Concentrations of POPs in Gammarus were negatively correlated with total phosphorus and positively correlated with the percentage of the catchment slumped. Lakes with slumps generally had higher mean concentrations of POPs in Gammarus (ex. ΣPCBsDisturbed = 27.54 ng/g lipid, ΣPCBsUndisturbed = 16.97 ng/g lipid; ΣDDT Disturbed =18.47 ng/g lipid and ΣDDTUndisturbed =10.86 ng/g lipid). Benthic invertebrate biomass was also negatively correlated with concentrations of contaminants in Gammarus, supporting the biomass dilution hypothesis. Thaw slumps have large enough impacts on the physico-chemical characteristics of lakes that they alter benthic invertebrate community composition and size-structure, and contaminant concentrations in Gammarus.

Thesis (M.Sc. (Zoology)) -- University of Limpopo, 2019 / Freshwater ecosystems in South Africa are losing their quality and quantity over time due to pollution mainly from mining, agriculture, industries, deforestation, sewage systems, construction of dams, channel modification and over extraction of water. The Dwars River, a tributary of the Olifants River, is of no exception, as recent studies indicated an increase in nutrient input possibly from agriculture. The Dwars River is an important source of water for nearby communities (Ga-Mampuru). The aim of the study was to assess water and sediment quality of the Dwars River using macroinvertebrates as bioindicators of pollution. Water and macroinvertebrates sampling were done seasonally from July 2017 to May 2018. The water quality results indicated that non-toxic constituents such as salinity and EC (Electrical Conductivity) were above permissible limits stipulated by the DWAF (1996) guidelines. More sensitive taxa were found upstream, despite high concentrations of some nutrients and metals in the water column. The high abundance and distribution of macroinvertebrates observed upstream was confirmed by the Canonical Correspondence Analysis (CCA), South African Scoring System (SASS5) and Average Score Per Taxon (ASPT) results during the study. Site 1 was dominated by the most sensitive taxa and this could be due to high dissolved oxygen content and increased heterogeneity of the area. Site 4 was dominated by the most tolerant taxa, according to the CCA, SASS score and ASPT results. This could possibly be due to the nutrients and heavy metals washed from upstream, which get adsorbed by the sediment. The results for species abundance, diversity and richness indicated that Ephemeroptera was the most abundant, while Diptera was the most diverse. Ephemeropterans are known to be indicators of good water quality. Site 1 had the highest number of families and orders while site 4 had the least families and orders. Ephemeroptera, Plecoptera and Tricoptera (EPT) taxa richness and Shannon diversity (H’) index values are high upstream and decrease downstream. Overall, the SASS5 indices, CCA and physicochemical results indicated that the water quality in the Dwars River is deteriorating in most impacted sites / National Research Foundation (NRF) and VLIR

North American prairie headwater streams are highly threatened and relatively poorly studied. Most studies on prairie streams have occurred at the Konza Prairie Biological Station, a tallgrass prairie Long Term Ecological Research site in the Flint Hills ecoregion near Manhattan, KS. According to the Stream Biome Gradient Concept, several ecosystem factors vary along a gradient from more allochthonous forested streams to more autochthonous desert streams, with grassland streams often intermediate in several key ecological factors including litter inputs, primary production, and invertebrate abundance and biomass. However, few studies have examined the degree of variation that exists within prairie headwater streams, and whether this variation occurs along a longitudinal gradient as well, with more mesic tallgrass prairie streams differing from more xeric shortgrass prairie streams, and mixed-grass sites intermediate between the two. I examined thirteen prairie headwater stream sites in the central United States from 2014 to 2017. My objective was to determine whether basal resource composition – including standing stocks of coarse particulate organic matter (CPOM), fine particulate organic matter (FPOM), and very fine particulate organic matter (VFPOM), sestonic and benthic chlorophyll-a levels, and sources of CPOM – differed significantly among streams in tallgrass, mixed-grass, and shortgrass prairie regions. In addition, I examined whether invertebrate communities differed among tallgrass, mixed-grass, and shortgrass prairie regions, and whether this was reflected in the functional feeding group composition, habit composition, voltinism, and dispersal ability of invertebrate communities. There were no significant differences in total CPOM, FPOM, and VFPOM standing stocks among regions. However, CPOM composition did differ with region, with tallgrass sites having higher standing stocks of leaf litter, but lower standing stocks of grass litter and macrophyte litter than the other regions. Benthic chlorophyll-a did not differ significantly among regions, but there were lower sestonic chlorophyll-a levels in tallgrass sites. Given higher light availability and nutrient levels in shortgrass and mixed-grass streams, lack of stable substrata may be limiting benthic algae in these regions. Invertebrate abundance and biomass were highest in mixed-grass sites and lowest in tallgrass sites, with shortgrass sites intermediate. Mixed-grass sites also had significantly higher Shannon diversity and taxa richness than tallgrass sites. A NMDS revealed that sites differed in overall community structure. Functional feeding group composition did not differ significantly across regions, with collector-gatherers, followed by predators, dominating in all sites. High Predator-Prey Index (predator biomass: other invertebrate biomass) values in each region indicates strong top-down pressure and high turnover rates of prey taxa. While there was a weak correlation between leaf litter AFDM and invertebrate community structure, the correlation between latitude and longitude and invertebrate community structure was much higher, indicating that basal resources may not be the main drivers in these systems. Invertebrate habit composition did not differ with region; all regions were dominated by taxa preferring fine substrata (burrowers and sprawlers). All regions showed selection against semivoltine invertebrates and were dominated by high dispersing insect taxa, though the proportion of the insect community that consisted of high dispersers did not differ significantly with region. My results suggest that generalizing about prairie streams based on studies from one or a handful of sites may not be prudent, at least for some aspects. The higher proportion of autochthonous inputs in shortgrass and mixed-grass regions may drive increased invertebrate abundance, biomass, richness, and diversity, but the relative hydrologic stability of the mixed-grass sites might also explain these results or have an interactive or additive relationship with primary production. Overall, the link between basal resources and communities across prairie types was somewhat weak, and all regions were dominated by collector-gatherers with rapid life-cycles and high dispersal abilities, indicating that disturbance may be a more important community filter than basal resource composition. Streams in all three regions have highly variable hydrology, and this may be an overriding factor that results in similarity in communities.

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