Ecological assessment of a southeastern Brazil reservoir

Reservoirs are artificial ecosystems with multiple functions having direct and indirect benefits to humans; however, they also cause ecological changes and influence the composition and structure of aquatic biota. Our objectives were to: (1) assess the environmental condition of Nova Ponte Reservoir, Minas Gerais state, southeastern Brazil; and (2) determine how the aquatic biota respond to disturbances. A total of 40 sites in the littoral zone of the reservoir were sampled to characterize physical and chemical habitat, land use, and benthic macroinvertebrate and fish assemblages. The predominant type of land cover near the reservoir was natural vegetation. A total of 29 fish species and 39 macroinvertebrate taxa were collected, including eight alien species. Most sites had intermediate levels of human disturbance, however, high levels of degradation were associated with high proportions of alien species. Disturbances at multiple scales may alter natural patterns and processes, leading to environmental changes and damaging biological communities. Our results reinforce the importance of assessing reservoir ecological conditions at several scales. The study of land use, littoral zone physical habitat characteristics, water quality, and assemblage structure set the ground for proposing actions to rehabilitate and conserve aquatic ecosystems.

Download Full-text

Historical Changes in Large River Fish Assemblages of the Americas

Historical Changes in Large River Fish Assemblages of the Americas ◽

10.47886/9781888569728.ch6 ◽

2005 ◽

Keyword(s):

Alien Species ◽

Environmental Changes ◽

Fish Assemblages ◽

Fish Fauna ◽

Large River ◽

Gold Rush ◽

Physical Habitat ◽

San Joaquin River ◽

The Status ◽

Native Fishes

Abstract.—In this paper, we review information regarding the status of the native fishes of the combined Sacramento River and San Joaquin River drainages (hereinafter the “Sacramento–San Joaquin drainage”) and the factors associated with their declines. The Sacramento–San Joaquin drainage is the center of fish evolution in California, giving rise to 17 endemic species of a total native fish fauna of 28 species. Rapid changes in land use and water use beginning with the Gold Rush in the 1850s and continuing to the present have resulted in the extinction, extirpation, and reduction in range and abundance of the native fishes. Multiple factors are associated with the declines of native fishes, including habitat alteration and loss, water storage and diversion, flow alteration, water quality, and invasions of alien species. Although native fishes can be quite tolerant of stressful physical conditions, in some rivers of the drainage the physical habitat has been altered to the extent that it is now more suited for alien species. This interaction of environmental changes and invasions of alien species makes it difficult to predict the benefits of restoration efforts to native fishes. Possible effects of climate change on California’s aquatic habitats add additional complexity to restoration of native fishes. Unless protection and restoration of native fishes is explicitly considered in future water management decisions, declines are likely to continue.

Download Full-text

Landscape Influences on Stream Habitats and Biological Assemblages

Landscape Influences on Stream Habitats and Biological Assemblages ◽

10.47886/9781888569766.ch15 ◽

2006 ◽

Keyword(s):

Water Quality ◽

Land Use ◽

Fish Assemblages ◽

Stream Water ◽

Riparian Buffers ◽

Physical Habitat ◽

Land Uses ◽

Stream Water Quality ◽

Agricultural Streams ◽

And Function

Abstract.—Ecologists recognize that surrounding land use can influence the structure and function of aquatic ecosystems, but few studies have explicitly examined the relative effects of different types of land use on stream ecosystems. We quantified the relationships between different land uses (forested, urban, agricultural with or without riparian buffers) and stream physicochemical variables and resident fish assemblages in 21 southwestern Michigan streams. These streams were located within a single basin (Kalamazoo River) and ecoregion to minimize differences in natural landscape conditions. Streams responded to a gradient of land use, with forested streams having the least degraded water quality, physical habitat, and fish assemblages, and agricultural streams lacking buffers being the most degraded. Urban and agricultural streams with buffers displayed characteristics intermediate to forested and agricultural streams lacking buffers. In general, habitat complexity and water quality declined across this land-use gradient from forested to agricultural streams, whereas fish density, richness, and dominance by tolerant species increased along the land-use gradient. Although urban streams had lower percentages of altered land use (i.e., <40% urban) in their catchments compared to agricultural streams (i.e., >50% agriculture), both land uses appeared to have similar detrimental effects on streams suggesting higher per unit area impacts of urbanization on streams. The presence of forested riparian buffers along agricultural streams increased the complexity of instream habitat, but resulted in few benefits to fish assemblages, suggesting that stream water quality in altered landscapes may be constraining fish assemblages more than physical habitat.

Download Full-text

Changes in ichthyofauna composition along a gradient from clearwaters to blackwaters in coastal streams of Atlantic forest (southeastern Brazil) in relation to environmental variables

Neotropical Ichthyology ◽

10.1590/s1679-62252012000300022 ◽

2012 ◽

Vol 10 (3) ◽

pp. 675-684 ◽

Cited By ~ 13

Author(s):

Cristina da Silva Gonçalves ◽

Francisco Manoel de Souza Braga

Keyword(s):

Atlantic Forest ◽

Fish Assemblages ◽

Habitat Characteristics ◽

Southeastern Brazil ◽

Fish Samples ◽

Spatial Differences ◽

Coastal Streams ◽

Longitudinal Variations ◽

Physical And Chemical Variables ◽

Physical And Chemical

The lack of knowledge of the freshwater ichthyofauna of coastal streams in the State of São Paulo (Brazil) is a cause of concern, as these streams are inserted in the Atlantic forest, a hotspot highly threatened. The aim of the present study is to investigate the freshwater ichthyofauna composition of clear and blackwater streams in a preservation area of Brazilian Atlantic forest. Fish samples were taken using electrofishing. A total of 20 species were registered, with Astyanax ribeirae, Hollandichthys multifasciatus, and Mimagoniates microlepis (Characiformes, Characidae) as the more representative. In general, the observed pattern of occurrence and distribution of fish species varied according to habitat characteristics, due to the longitudinal gradient in clearwaters, and among clearwaters and blackwaters. In clearwater streams, the headwater stretches had lower species diversity, while the opposite occurred in the middle and lower sites. These longitudinal variations of ichthyofauna were related with habitat characteristics (depth, stream flow, and bottom type) in which they were found, since the diversity of habitats was higher in headwaters and lower in downstream reaches (middle and lower sites). The physical and chemical variables of water do not seem to have influenced the distribution of species in clearwater streams, but the clear and blackwater fish composition was influenced mainly by pH concentration. Unlike the spatial differences, significant temporal differences were not registered in fish assemblages, probably due to the absence of a pronounced dry season in the studied region.

Download Full-text

Homogenization of Fish Composition Among Mesohabitats Driven by Stream Degradation from Urban Land Use

10.21203/rs.3.rs-503555/v1 ◽

2021 ◽

Author(s):

Leonardo Antunes Pessoa ◽

Matheus T. Baumgartner ◽

Augusto Frota ◽

Thiago D. Garcia ◽

João Pagotto ◽

...

Keyword(s):

Land Use ◽

Species Composition ◽

Body Shape ◽

Fish Assemblages ◽

Urban Streams ◽

Urban Land Use ◽

The Body ◽

Habitat Characteristics ◽

Fish Diversity ◽

Body Morphology

Abstract The heterogeneity along the course of streams beget habitat features that are highly different and strongly influence the composition of fish assemblages. Stream stretches such as riffles, runs, and pools are particularly distinct in physical structures and water flow, with expected differences in the identity and body shape of the species that occupy these habitat units. However, how land is used in the adjacent areas of these aquatic environments also changes the habitat characteristics and, therefore, the fish composition from each stretch. In this context, we collected data from both rural and urban streams to assess how these land-use types influence the species composition and their body morphology among mesohabitats. Differences in body morphology were evaluated using Analysis of Variance (ANOVA) on the mean of Compression Index (CI) weighted by the species abundance for each sampled site. The differences in species composition were assessed using permutational multivariate analogous (PERMANOVA) and Indicator Value (IndVal). Urban streams showed a significantly decreased fish diversity combined with no differences in body morphology of fish and homogenization of species composition among mesohabitats. Importantly, we could infer that mesohabitats influence the body shape of fish and, consequently, species composition in less disturbed streams. However, the lower fish diversity in more imperiled streams led to the homogenization of fish composition among mesohabitats. These patterns constitute important contributions for evidence-based management and restoration of streams, as the presence of different mesohabitats is not enough to overcome the effects of urbanization on fish assemblages.

Download Full-text

Effects of Urbanization on Stream Ecosystems

Effects of Urbanization on Stream Ecosystems ◽

10.47886/9781888569735.ch14 ◽

2005 ◽

Keyword(s):

Land Use ◽

Alien Species ◽

Fish Assemblage ◽

Southern California ◽

Fish Assemblages ◽

Fish Abundance ◽

Watershed Land Use ◽

Land Use Types ◽

Coastal Streams ◽

Assemblage Metrics

Abstract.—Data collected as part of two studies to examine the influences of landscape modification on the ecology of three coastal Southern California river systems—the Calleguas Creek, Malibu Creek, and Santa Clara River watersheds—provided the opportunity to examine relations between urbanization and fish assemblages in Southern California coastal streams. Fish were collected at 63 sites from 1999 to 2001. Watershed land use was determined and classified into three land use types: agriculture, developed, and open space. Seven fish assemblage metrics were examined, including species richness, number of native and alien species, total fish abundance, percent abundance of native and alien species, and percent abundance of arroyo chub Gila orcuttii. Ten fish species were collected, and arroyo chub was the only species collected in all three watersheds. Native species included arroyo chub, threespine stickleback Gasterosteus aculeatus, steelhead Oncorhynchus mykiss, and Pacific staghorn sculpin Leptocottus armatus. There were no significant differences in fish assemblage metrics among the three land-use types. Both wetted stream width and depth were significantly related to native fish abundance. Results from this study suggest that the relatively species poor fish assemblages of Southern California may not be sensitive to watershed land use disturbance, but may be sensitive to local hydrologic conditions.

Download Full-text

Differential Responses to Climate and Land-Use Changes in Threatened Chinese Taxus Species

Forests ◽

10.3390/f10090766 ◽

2019 ◽

Vol 10 (9) ◽

pp. 766 ◽

Cited By ~ 2

Author(s):

Jianming Wang ◽

Yin Wang ◽

Jianmeng Feng ◽

Chen Chen ◽

Jie Chen ◽

...

Keyword(s):

Land Use ◽

Threatened Species ◽

Environmental Changes ◽

Higher Plants ◽

Land Use Changes ◽

Species Conservation ◽

Distribution Range ◽

Habitat Characteristics ◽

The Face ◽

Global Environmental Changes

Rapid climate and land-use changes have been considered as the foremost threat to global biodiversity. China contains more than 3500 threatened higher plants, whereas the relative influence of climate and land-use changes on these endangered plants have not been explored simultaneously under topographical constraints. Here, using Taxus plants as the case study genus, we simulated the distribution range of threatened species under three scenarios of current and future climate and land-use conditions under topographical constraints. We also measured the associated difference in the responses of Taxus species to climate and land-use changes. Our results demonstrated the substantial influence of climate and land-use changes on the distributions of Taxus species. However, we observed different responses of Taxus species to these environmental changes. The distribution range of T. cuspidate Siebold & Zuccarini and T. mairei Lemee & H. Léveillé would substantially shrink, whereas the habitat range of T. fuana Nan Li & R. R. Mill would sharply expand under RCP 8.5(Representative Concentration Pathway scenarios) scenario. Meanwhile, T. wallichiana Zuccarini and T. chinensis (Pilger) Florin would experience apparent range shifts. Furthermore, topographical factors played non-negligible roles in shaping species distributions, and modifying the influence of climate and land-use changes. Together, these results provide robust evidence that even threatened species will have multiple responses to climate and land-use changes (e.g., shrinking, expanding, shifting). Our findings highlight that taking species ecological traits, habitat characteristics, and topographical constraints into account might provide valuable insights into threatened species conservation in the face of global environmental changes.

Download Full-text

Ross Sea Benthic Ecosystems: Macro- and Mega-faunal Community Patterns From a Multi-environment Survey

Frontiers in Marine Science ◽

10.3389/fmars.2021.629787 ◽

2021 ◽

Vol 8 ◽

Author(s):

Vonda J. Cummings ◽

David A. Bowden ◽

Matthew H. Pinkerton ◽

N. Jane Halliday ◽

Judi E. Hewitt

Keyword(s):

Environmental Changes ◽

Marine Protected Area ◽

Ross Sea ◽

Spatial Scales ◽

Benthic Communities ◽

Benthic Fauna ◽

Habitat Characteristics ◽

Physical Habitat ◽

Distribution Models ◽

Suspension Feeders

The Ross Sea, Antarctica, is amongst the least human-impacted marine environments, and the site of the world’s largest Marine Protected Area. We present research on two components of the Ross Sea benthic fauna: mega-epifauna, and macro-infauna, sampled using video and multicore, respectively, on the continental shelf and in previously unsampled habitats on the northern continental slope and abyssal plain. We describe physical habitat characteristics and community composition, in terms of faunal diversity, abundance, and functional traits, and compare similarities within and between habitats. We also examine relationships between faunal distributions and ice cover and productivity, using summaries of satellite-derived data over the decade prior to our sampling. Clear differences in seafloor characteristics and communities were noted between environments. Seafloor substrates were more diverse on the Slope and Abyss, while taxa were generally more diverse on the Shelf. Mega-epifauna were predominantly suspension feeders across the Shelf and Slope, with deposit feeder-grazers found in higher or equal abundances in the Abyss. In contrast, suspension feeders were the least common macro-infaunal feeding type on the Shelf and Slope. Concordance between the mega-epifauna and macro-infauna data suggests that non-destructive video sampling of mega-epifauna can be used to indicate likely composition of macro-infauna, at larger spatial scales, at least. Primary productivity, seabed organic flux, and sea ice concentrations, and their variability over time, were important structuring factors for both community types. This illustrates the importance of better understanding bentho-pelagic coupling and incorporating this in biogeographic and process-distribution models, to enable meaningful predictions of how these ecosystems may be impacted by projected environmental changes. This study has enhanced our understanding of the distributions and functions of seabed habitats and fauna inside and outside the Ross Sea MPA boundaries, expanding the baseline dataset against which the success of the MPA, as well as variability and change in benthic communities can be evaluated longer term.

Download Full-text

Abiotic features of a river from the Upper Tietê River Basin (SP, Brazil) along an environmental gradient

Acta Limnologica Brasiliensia ◽

10.1590/s2179-975x5914 ◽

2015 ◽

Vol 27 (2) ◽

pp. 228-237 ◽

Cited By ~ 6

Author(s):

Katharina Eichbaum Esteves ◽

Ana Valéria Pinto Lôbo ◽

Alexandre Wagner Silva Hilsdorf

Keyword(s):

Land Use ◽

Riparian Vegetation ◽

Secondary Forest ◽

Canopy Cover ◽

Habitat Characteristics ◽

Native Forest ◽

Physical Habitat ◽

Potential Influence ◽

Tietê River ◽

Spatial And Seasonal Variation

Aim: This study aimed to assess the spatial and seasonal variation of the water quality and physical habitat characteristics along the upper-middle stretch of the Paraitinga River, a tributary of Tietê River, considering the potential influence of different riparian conditions along the stretch studied.MethodsSixteen sites with different riparian vegetation, including native forest, secondary forest, pasture, and eucalyptus were sampled during the dry and rainy seasons of 2004/2005, before the damming of the Paraitinga Reservoir. Several physicochemical and habitat parameters were determined and data analyzed in relation to spatial distribution and potential influence of riparian conditions.ResultsWater quality parameters were in general within the limits established by CONAMA for Class 2 waters, except for turbidity and total phosphorus. There were seasonal and spatial differences in the limnological parameters along the stretch studied and apparently they were related to point specific influences associated with land use and canopy cover. Habitat characteristics were markedly different between the upper and middle river stretches, especially in relation to depth, width, substrate and canopy cover.ConclusionsAlthough a direct influence on the observed variables could not be attributed solely to the riparian vegetation, vegetation cover seemed to affect particular stream characteristics. Open pasture and eucalyptus sites were subject to point specific effects that caused phosphorus inputs and higher turbidity and temperature, and showed different morphological features, suggesting that land use at the sub-watershed scale was an important factor affecting stream conditions.

Download Full-text

Use of functional traits to assess changes in stream fish assemblages across a habitat gradient

Neotropical Ichthyology ◽

10.1590/1982-0224-20140185 ◽

2016 ◽

Vol 14 (1) ◽

Cited By ~ 26

Author(s):

Mariela Domiciano Ribeiro ◽

Fabrício Barreto Teresa ◽

Lilian Casatti

Keyword(s):

Functional Traits ◽

Environmental Conditions ◽

Habitat Structure ◽

Trophic Ecology ◽

Fish Assemblages ◽

Habitat Degradation ◽

Species Traits ◽

Habitat Characteristics ◽

Physical Habitat ◽

Habitat Gradient

Abstract Functional traits are important for understanding the links between species occurrence and environmental conditions. Identifying these links makes it possible to predict changes in species composition within communities under specific environmental conditions. We used functional traits related to habitat use and trophic ecology in order to assess the changes in fish community composition between streams with varying habitat structure. The relationship between the species traits and habitat characteristics was analyzed using an RLQ ordination analysis. Although species were widely distributed in habitats with different structures, physical conditions did favor some species based on their functional characteristics. Eight functional traits were found to be associated with stream habitat structure, allowing us to identify traits that may predict the susceptibility of fish species to physical habitat degradation.

Download Full-text

Landscape Influences on Stream Habitats and Biological Assemblages

Landscape Influences on Stream Habitats and Biological Assemblages ◽

10.47886/9781888569766.ch17 ◽

2006 ◽

Keyword(s):

Land Use ◽

Land Cover ◽

Agricultural Land ◽

Fish Assemblages ◽

Model Fit ◽

Biotic Integrity ◽

Agricultural Land Use ◽

Physical Habitat ◽

Natural Land ◽

Fine Gravel

Abstract.—The influence of land use and instream physical habitat on biotic condition of fish assemblages was investigated for 48 stream reaches in the Huron and Raisin rivers. The amount of agriculture and wetland in the catchment and 100-m stream buffers had the strongest relationships with instream physical habitat, and these two categories of land use/cover were negatively correlated with each other (r = –0.70, p = <0.01). Agriculture was associated with high levels of sedimentation and reduced flow stability, while wetland was associated with low sedimentation and stable flows. The index of biotic integrity (IBI) was positively related to low sedimentation, stable flows, and the presence of fine gravel (2–8 mm). It was not significantly correlated with agricultural land use, but was positively related to natural land cover (forest + wetland combined) in the buffer. The best linear regression model using physical habitat and land-use variables from all sites adequately predicted IBI scores (adjusted R2 = 0.52). However, when the Huron and Raisin basins were treated separately, some of the included variables differed, and model fit increased (Huron adjusted R2 = 0.76, Raisin adj. R2 = 0.79), indicating that relations of fish assemblages to physical habitat and land use differed between basins. The Raisin model included land cover variables, while the Huron model included only variables related to physical habitat. Thus instream habitat and land cover may play different roles in these basins, suggesting the benefit of forming separate models for individual basins when sufficient data are available.

Download Full-text