Effect of daily variation on the seasonality of testate amoebae community structure in different environments of a Neotropical floodplain

<p>Ecological communities are constantly restructuring in the short and long term in response to population dynamics and environmental variables. This study evaluated the structure of arcellinid and euglyphid testate amoebae planktonic communities in three environments of the Upper Paraná River basin, Brazil. We hypothesised that the community structure of testate amoebae is differentially influenced by environmental conditions, mainly in isolated lentic ecosystems, due the effect of the low-water period. In addition, we predicted that the response of testate amoeba communities to environmental changes is also affected by the distinct hydrodynamic characteristics of the environment. Plankton were sampled in the low- and high-water periods, and physical and chemical variables were calculated for each site. In order to evaluate the influence of environmental conditions on the variation in testate amoebae community structure over time, a time-lag analytical approach was used and significance was estimated using a Mantel test. A Kendall test coefficient was used to estimate the maintenance of species abundance on each day when sampling was carried out and for each water body. A redundancy analysis was also performed to assess the responses of testate amoeba communities to environmental change in the three studied environments. Bray–Curtis dissimilarity indices were calculated for the testate amoeba communities and the significance of the differences between communities was estimated using a Mantel test. Seventy-five taxa belonging to six families were identified. Environmental conditions influenced the richness, abundance, and dominance pattern of the testate amoebae communities, and distinct hydrodynamic characteristics of the environments affected the establishment of community structure.</p>

Download Full-text

Past testate amoeba communities in landslide mountain fens (Polish Carpathians): The relationship between shell types and sediment

The Holocene ◽

10.1177/0959683621994647 ◽

2021 ◽

pp. 095968362199464

Author(s):

Katarzyna Marcisz ◽

Krzysztof Buczek ◽

Mariusz Gałka ◽

Włodzimierz Margielewski ◽

Matthieu Mulot ◽

...

Keyword(s):

Environmental Changes ◽

Testate Amoebae ◽

Mineral Matter ◽

Testate Amoeba ◽

Run Off ◽

Number Of Factors ◽

Depth To Water Table ◽

Polish Carpathians ◽

The Relationship

Landslide mountain fens formed in landslide depressions are dynamic environments as their development is disturbed by a number of factors, for example, landslides, slopewash, and surface run-off. These processes lead to the accumulation of mineral material and wood in peat. Disturbed peatlands are interesting archives of past environmental changes, but they may be challenging for providing biotic proxy-based quantitative reconstructions. Here we investigate long-term changes in testate amoeba communities from two landslide mountain fens – so far an overlooked habitat for testate amoeba investigations. Our results show that abundances of testate amoebae are extremely low in this type of peatlands, therefore not suitable for providing quantitative depth-to-water table reconstructions. However, frequent shifts of dominant testate amoeba species reflect dynamic lithological situation of the studied fens. We observed that high and stable mineral matter input into the peatlands was associated with high abundances of species producing agglutinated (xenosomic) as well as idiosomic shells which prevailed in the testate amoeba communities in both analyzed profiles. This is the first study that explores testate amoebae of landslide mountain fens in such detail, providing novel information about microbial communities of these ecosystems.

Download Full-text

Emergent Rarity Properties in Carabid Communities From Chinese Steppes With Different Climatic Conditions

Frontiers in Ecology and Evolution ◽

10.3389/fevo.2021.603436 ◽

2021 ◽

Vol 9 ◽

Author(s):

Noelline Tsafack ◽

Paulo A. V. Borges ◽

Yingzhong Xie ◽

Xinpu Wang ◽

Simone Fattorini

Keyword(s):

Community Structure ◽

Environmental Conditions ◽

Large Scale ◽

Species Abundance ◽

Climatic Conditions ◽

Carabid Beetles ◽

Model Parameters ◽

Desert Steppe ◽

Best Fit ◽

Scale Of Analysis

Species abundance distributions (SADs) are increasingly used to investigate how species community structure changes in response to environmental variations. SAD models depict the relative abundance of species recorded in a community and express fundamental aspects of the community structure, namely patterns of commonness and rarity. However, the influence of differences in environmental conditions on SAD characteristics is still poorly understood. In this study we used SAD models of carabid beetles (Coleoptera: Carabidae) in three grassland ecosystems (desert, typical, and meadow steppes) in China. These ecosystems are characterized by different aridity conditions, thus offering an opportunity to investigate how SADs are influenced by differences in environmental conditions (mainly aridity and vegetation cover, and hence productivity). We used various SAD models, including the meta-community zero sum multinomial (mZSM), the lognormal (PLN) and Fisher’s logseries (LS), and uni- and multimodal gambin models. Analyses were done at the level of steppe type (coarse scale) and for different sectors within the same steppe (fine scale). We found that the mZSM model provided, in general, the best fit at both analysis scales. Model parameters were influenced by the scale of analysis. Moreover, the LS was the best fit in desert steppe SAD. If abundances are rarefied to the smallest sample, results are similar to those without rarefaction, but differences in models estimates become more evident. Gambin unimodal provided the best fit with the lowest α-value observed in desert steppe and higher values in typical and meadow steppes, with results which were strongly affected by the scale of analysis and the use of rarefaction. Our results indicate that all investigated communities are adequately modeled by two similar distributions, the mZSM and the LS, at both scales of analyses. This indicates (1) that all communities are characterized by a relatively small number of species, most of which are rare, and (2) that the meta-communities at the large scale maintain the basic SAD shape of the local communities. The gambin multimodal models produced exaggerated α-values, which indicates that they overfit simple communities. Overall, Fisher’s α, mZSM θ, and gambin α-values were substantially lower in the desert steppe and higher in the typical and meadow steppes, which implies a decreasing influence of environmental harshness (aridity) from the desert steppe to the typical and meadow steppes.

Download Full-text

Empirically modelling the potential effects of changes in temperature and prey availability on the growth of cod larvae in UK shelf seas

ICES Journal of Marine Science ◽

10.1093/icesjms/fsn150 ◽

2008 ◽

Vol 65 (9) ◽

pp. 1559-1572 ◽

Cited By ~ 7

Author(s):

Sophie G. Pitois ◽

Clive J. Fox

Keyword(s):

Community Structure ◽

Environmental Changes ◽

Atlantic Cod ◽

Prey Availability ◽

Life Stage ◽

Larval Growth ◽

Species Abundance ◽

Zooplankton Community ◽

Zooplankton Community Structure ◽

Shelf Seas

Abstract Pitois, S. G., and Fox, C. J. 2008. Empirically modelling the potential effects of changes in temperature and prey availability on the growth of cod larvae in UK shelf seas. – ICES Journal of Marine Science, 65: 1559–1572. It has been hypothesized that changes in zooplankton community structure over the past four decades led to reduced growth and survival of prerecruit Atlantic cod (Gadus morhua) and that this was a key factor underlying poor year classes, contributing to stock collapse, and inhibiting the recovery of stocks around the UK. To evaluate whether observed changes in plankton abundance, species composition and temperature could have led to periods of poorer growth of cod larvae, we explored the effect of prey availability and temperature on early larval growth using an empirical trophodynamic model. Prey availability was parameterized using species abundance data from the Continuous Plankton Recorder. Our model suggests that the observed changes in plankton community structure in the North Sea may have had less impact on cod larval growth, at least for the first 40 days following hatching, than previously suggested. At least in the short term, environmental and prey conditions should be able to sustain growth of cod larvae and environmental changes acting on this early life stage should not limit stock recovery.

Download Full-text

Partitioning the temporal changes in abundance-based beta diversity into loss and gain components

10.1101/2021.05.28.446095 ◽

2021 ◽

Author(s):

Shinichi Tatsumi ◽

Ryosuke Iritani ◽

Marc W Cadotte

Keyword(s):

Community Structure ◽

Species Composition ◽

Spatial Variation ◽

Beta Diversity ◽

Temporal Dynamics ◽

Species Abundance ◽

Temporal Changes ◽

Ecological Communities ◽

Multiple Site ◽

Unified Approach

Spatial variation in species composition, or beta diversity, plays a central role in gauging the structure of ecological communities. Here, we develop a new numerical method to partition the impacts of abundance losses and gains on the temporal changes in spatial beta diversity. We show that the temporal changes in pairwise dissimilarity measures (Ruzka and Bray-Curtis indices) and a multiple-site measure (normalized Whittaker's beta) can be partitioned into six terms that reflect the losses and gains in species abundance. Our new method provides a unified approach to disentangle the temporal dynamics of spatial community structure by means of either incidence- or abundance-based data.

Download Full-text

The Canary in the Coal Mine: Testate Amoebae Record Anthropogenic Impacts in Sediments of Oligotrophic Lake George, NY, USA

The Journal of Foraminiferal Research ◽

10.2113/gsjfr.50.2.128 ◽

2020 ◽

Vol 50 (2) ◽

pp. 128-140

Author(s):

Krystyna M. Kornecki ◽

Matthew S. Schuler ◽

Miraim E. Katz ◽

Rick A. Relyea ◽

Francine M. G. McCarthy ◽

...

Keyword(s):

Water Quality ◽

Environmental Changes ◽

Anthropogenic Impacts ◽

Testate Amoebae ◽

Oligotrophic Lake ◽

Quality Data ◽

Testate Amoeba ◽

Water Quality Data ◽

Salt Loading ◽

Lake George

ABSTRACT Lake George (NY) is surrounded by Forever Wild Forest in the Adirondack Park and has a Class AA Special water quality rating, yet lake monitoring has revealed increasing anthropogenic impacts from salt and nutrient loading over the past 30 years. To reconstruct anthropogenic influence on the lake (e.g., salt loading, eutrophication, climate warming), we characterized modern stable isotopes and testate amoeba and diatom assemblages in surface sediments from 33 lake-wide sites and compared their variability to 36 years of water-quality data. Linear regression analyses support testate amoebae as rapid responders and recorders of environmental change because taxa are strongly correlated with percent change of important water quality parameters. Our assessment indicates that: 1) Netzelia gramen is associated with aquatic plants and filamentous algae, making them a valuable aquatic plant/alga indicator, which is supported by the co-occurrence of the diatom Cocconeis spp.; 2) difflugids are generally good indicators of eutrophication, except for Difflugia protaeiformis; and 3) seasonal differences in water quality trends are reflected in the fossil record on decadal time scales. We show that testate amoebae are highly sensitive to small environmental changes in an oligotrophic lake and exhibit established relationships from eutrophic and mesotrophic lakes as well as new, likely oligotrophic-specific correlations. Correlation coefficients of water quality variables and strains within a species also illustrate gradational relationships, suggesting testate amoebae exhibit ecophenotypic plasticity. Diatom and testate amoeba assemblages categorize modern lakebed sites into four subgroups: 1) benthic macrophyte; 2) high nutrient; 3) high alkalinity; and 4) salt loading assemblages.

Download Full-text

Comparing and improving methods for reconstructing peatland water-table depth from testate amoebae

The Holocene ◽

10.1177/0959683619846969 ◽

2019 ◽

Vol 29 (8) ◽

pp. 1350-1361

Author(s):

Connor Nolan ◽

John Tipton ◽

Robert K Booth ◽

Mevin B Hooten ◽

Stephen T Jackson

Keyword(s):

Water Table ◽

Compositional Data ◽

Testate Amoebae ◽

Water Table Depth ◽

Weighted Averaging ◽

Training Dataset ◽

Testate Amoeba ◽

Test Case ◽

Ecological Communities ◽

Validation Experiment

Proxies that use changes in the composition of ecological communities to reconstruct temporal changes in an environmental covariate are commonly used in paleoclimatology and paleolimnology. Existing methods, such as weighted averaging and modern analog technique, relate compositional data to the covariate in very simple ways, and different methods are seldom compared systematically. We present a new Bayesian model that better represents the underlying data and the complexity in the relationships between species’ abundances and a paleoenvironmental covariate. Using testate amoeba–based reconstructions of water-table depth as a test case, we systematically compare new and existing models in a cross-validation experiment on a large training dataset from North America. We then apply the different models to a new 7500-year record of testate amoeba assemblages from Caribou Bog in Maine and compare the resulting water-table depth reconstructions. We find that Bayesian models represent an improvement over existing methods in three key ways: more complete use of the underlying compositional data, full and meaningful treatment of uncertainty, and clear paths toward methodological improvements. Furthermore, we highlight how developing and systematically comparing methods lead to an improved understanding of the proxy system. This paper focuses on testate amoebae and water-table depth, but the framework and ideas are widely applicable to other proxies based on compositional data.

Download Full-text

Komposisi dan Kelimpahan Ophiuroidea dan Echinoidea di Perairan Pantai Pok Tunggal, Gunung Kidul, Yogyakarta

Journal of Marine Research ◽

10.14710/jmr.v9i2.26101 ◽

2020 ◽

Vol 9 (2) ◽

pp. 109-118

Author(s):

Herlina Lestari Pakpahan ◽

Irwani Irwani ◽

Ita Widowati

Keyword(s):

Water Quality ◽

Community Structure ◽

Data Analysis ◽

Coral Reefs ◽

Environmental Conditions ◽

Diversity Index ◽

Species Abundance ◽

Temperature Data ◽

Dominance Index ◽

Index Value

ABSTRAK: Echinodermata merupakan salah satu komponen penting dalam keaneka ragaman fauna di ekosistem pantai. Habitat utama echinodermata adalah terumbu karang, hal ini karena terumbu karang berperan sebagai tempat berlindung dan mencari makan bagi fauna echinodermata. Salah satu penyebaran biota ini adalah di perairan rataan terumbu karang pantai selatan di pantai Pok Tunggal, Gunung Kidul, Yogyakarta. Tujuan penelitian ini adalah untuk mengetahui jenis dan struktur komunitas echinodermata di pantai Pok Tunggal, kabupaten Gunung Kidul, Yogyakarta. Penelitian ini dilaksanakan pada bulan Juli 2019 di pantai Pok Tunggal. Metode pengambilan data kelimpahan menggunakan metode transek kuadrat berukuran 1x1 m, parameter kualitas perairan yang diukur adalah salinitas, DO, pH, serta suhu. Analisis data meliputi identifikasi spesies, kelimpahan jenis (ind/m2), indeks keanekaragaman, indeks keseragaman dan indeks dominansi. Hasil pengamatan ditemukan beberapa spesies, dari 2 kelas filum echinodermata, antara lain 2 species dari kelas Ophiuroidea yaitu Ophiocoma erinaceus dan Ophiocoma dentata, 3 species dari kelas Echinoidea yaitu Echinometra oblonga, Echinometra mathei dan Echinothrix diadema. Hasil penelitian menunjukkan kelimpahan individu tertinggi adalah Echinometra oblonga (16,6 ind/m2) dan terendah adalah Echinothrix diadema (0,4 ind/m2). Parameter lingkungan perairan di pantai Pok Tunggal pada setiap stasiun masih menunjang kehidupan Echinodermata. Struktur komunitas echinodermata yaitu nilai indeks keanekaragaman (H‟) berkisar antara 0,667-1,198, nilai indeks keseragaman (E) berkisar antara 0,744 - 0,999 dan nilai indeks dominansi (C) berkisar berkisar 0,308 - 0,525. ABSTRACT: Echinoderms are one of important component of fauna diversity in coastal ecosystems. The main habitat of Echinoderms is coral reefs, because coral reefs act as a shelter and food for echinoderms fauna. This species distributed in the flat waters of the coral reefs of the south coast at Pok Tunggal beach, Gunung Kidul, Yogyakarta. The aim of this study was to determine the species and Community Structure of echinoderms on the Pok Tunggal beach, Gunung Kidul Regency, Yogyakarta. This research was conducted in July 2018 at Pok Tunggal Beach. Sampling was done by using transect quadrant measuring 1x1 m. Parameter of water quality was salinity, DO, pH, and temperature. Data analysis includes species abundance (ind/m2), diversity index, uniformity index and dominance index. The result showed that several species of Echinodermal phylum classes, including 2 species of Ophiuroidea class namely Ophiocoma erinaceus and Ophiocoma dentata, 3 species of Echinoidea class namely Echinometra oblonga, Echinometra mathei and Echinothrix diadema. The highest individual abundance was Echinometra oblonga (16,6 ind/m2) and the lowest was Echinothrix diadema (0,4 ind/m2). The environmental conditions of the waters at the Pok Tunggal beach at each station can support the life of echinoderms. Echinoderms community structure, namely diversity index (H ') ranges from 0,667-1,198, uniformity index (E) ranges from 0,744-0,999 and dominance index value ranges (C) ranges from 0,308-0,525.

Download Full-text

Dissolved oxygen and temperature best predict deep-sea fish community structure in the Gulf of California with climate change implications

Marine Ecology Progress Series ◽

10.3354/meps13240 ◽

2020 ◽

Vol 637 ◽

pp. 159-180

Author(s):

ND Gallo ◽

M Beckwith ◽

CL Wei ◽

LA Levin ◽

L Kuhnz ◽

...

Keyword(s):

Climate Change ◽

Community Structure ◽

Community Composition ◽

Environmental Conditions ◽

Deep Sea ◽

Gulf Of California ◽

Fish Community ◽

Demersal Fish ◽

Fish Community Structure ◽

Explained Variance

Natural gradient systems can be used to examine the vulnerability of deep-sea communities to climate change. The Gulf of California presents an ideal system for examining relationships between faunal patterns and environmental conditions of deep-sea communities because deep-sea conditions change from warm and oxygen-rich in the north to cold and severely hypoxic in the south. The Monterey Bay Aquarium Research Institute (MBARI) remotely operated vehicle (ROV) ‘Doc Ricketts’ was used to conduct seafloor video transects at depths of ~200-1400 m in the northern, central, and southern Gulf. The community composition, density, and diversity of demersal fish assemblages were compared to environmental conditions. We tested the hypothesis that climate-relevant variables (temperature, oxygen, and primary production) have more explanatory power than static variables (latitude, depth, and benthic substrate) in explaining variation in fish community structure. Temperature best explained variance in density, while oxygen best explained variance in diversity and community composition. Both density and diversity declined with decreasing oxygen, but diversity declined at a higher oxygen threshold (~7 µmol kg-1). Remarkably, high-density fish communities were observed living under suboxic conditions (<5 µmol kg-1). Using an Earth systems global climate model forced under an RCP8.5 scenario, we found that by 2081-2100, the entire Gulf of California seafloor is expected to experience a mean temperature increase of 1.08 ± 1.07°C and modest deoxygenation. The projected changes in temperature and oxygen are expected to be accompanied by reduced diversity and related changes in deep-sea demersal fish communities.

Download Full-text