Environmental change and its effects on inter-decadal variations of diatom production, species composition and frustule dissolution in a coastal marginal sea

The general limnology and fish composition of 14 North American oligotrophic lakes is described as it likely was about the year 1800, prior to the adverse effects of man-made eutrophication, exploitation, and introductions of exotic species. The general description includes glacial history and geomorphology, climate and growing season, morphometry of the lake basins, physical and chemical characteristics, macroinvertebrates, and zooplankton. Fish populations are described with respect to their zoogeographic origins and the species composition of each lake. The relative degree of environmental change brought about by the activities of man in each lake is summarized.

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Komunitas Gastropoda Mangrove di Sungai Perpat dan Bunting, Kecamatan Belinyu, Kabupaten Bangka

Oseanologi dan Limnologi di Indonesia ◽

10.14203/oldi.2021.v6i2.361 ◽

2021 ◽

Vol 6 (2) ◽

pp. 85

Author(s):

Eka Yuliawati ◽

Budi Afriyansyah ◽

Nova Mujiono

Keyword(s):

Species Composition ◽

Environmental Change ◽

Dominant Species ◽

Mangrove Ecosystem ◽

Species Number ◽

Mangrove Area ◽

Number Of Species ◽

Mangrove Ecosystems ◽

Number Of Individuals

Mangrove gastropod community in Perpat and Bunting Rivers, Belinyu District, Bangka Regency. Perpat and Bunting in Bangka Regency have an adequate and natural mangrove ecosystems. However, studies on the structure of the gastropod community in this ecosystem is lacking. This study aimed to discover the structure of the gastropod community in the mangrove ecosystem. This study was carried out from October to November 2019 in riverine mangrove area located in Perpat and Bunting Rivers, District Belinyu, Bangka Regency. Samples were taken from 10 x 10 m plot from six observed stations. A total of 578 individuals of gastropoda were collected, comprised of seven families and 14 species. Number of species ranged from 4 to 9, while number of individuals ranged from 35 to 214. Cerithidea quoyii was a dominant species with 270 individuals (47%) and found in all stations. Gastropods community was in labile condition and prone to environmental change. Species composition of gastropods were similar in both rivers with nine identical species. However, epifaunal species were found separately from arboreal species

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Functional Composition Changes of a Subtropical Monsoon Evergreen Broad-Leaved Forest Under Environmental Change

Forests ◽

10.3390/f11020191 ◽

2020 ◽

Vol 11 (2) ◽

pp. 191

Author(s):

Shun Zou ◽

Qianmei Zhang ◽

Guoyi Zhou ◽

Shizhong Liu ◽

Guowei Chu ◽

...

Keyword(s):

Hydraulic Conductivity ◽

Drought Tolerance ◽

Species Composition ◽

Environmental Change ◽

Subtropical Forest ◽

Functional Composition ◽

Composition Change ◽

Environment Change ◽

Soil Dryness ◽

Composition Changes

Long-term studies have revealed that forest species composition was shifting under environment change and disturbance induced by loss of large trees. Yet, few studies explicitly analyzed their impacts on composition concurrently. To learn more about impacts of environment change and disturbance on driving forest community, we investigated shifts in functional composition over past 24 years in an old-growth subtropical forest in southern China. We analyzed nine traits that are mainly related to leaf nutrients, photosynthetic capacity, hydraulic conductivity, and drought tolerance of plants and examined hypotheses: (1) The functional composition change over time was directional instead of random fluctuation, (2) drought-tolerant species increased their abundance under soil dryness, (3) both environmental change and disturbance related to changes of functional composition significantly, and (4) initial trait values of quadrats strongly influenced their subsequent change rates in quadrat level (10 × 10 m). We found that species composition had shifted to favor species with high leaf nutrient content, high photosynthesis rate, high hydraulic conductivity, low water-use efficiency, and high drought tolerance traits, which was due to soil dryness and disturbance. These two factors explained 47–58% of quadrats’ trait value changes together. Considering rapidly increasing stem density, this pattern may indicate ecological processes of which disturbance provided numerous recruits of resource-acquisition strategy species and soil dryness conducted a selecting effect on shaping composition in the forest. Additionally, quadrats with initial trait values at the far end of change direction shifted faster in three traits, which also indicated that functional composition changes in quadrats were directional and homogenized. Our results implied that environment change and accompanied disturbance events possibly drove species composition change along a different trajectory in the subtropical forest that experienced high climatic variability.

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Environment, diversity, evolution and Cope's Rule: Drivers of size in planktonic foraminifera.

10.5194/egusphere-egu2020-2977 ◽

2020 ◽

Author(s):

Heather Birch ◽

Daniela N. Schmidt ◽

Chloe Todd ◽

Marci M. Robinson ◽

Andy Fraass

Keyword(s):

High Resolution ◽

Species Composition ◽

Environmental Change ◽

Planktonic Foraminifera ◽

Maximum Diameter ◽

Individual Species ◽

Ecological Groups ◽

General Increase ◽

Foraminiferal Assemblage ◽

Extant Species

Within the marine fossil record, size is a fundamental trait providing information on both assemblages and individual species. Changes in size within an assemblage are largely driven by species composition typically related to environmental conditions. Changes in size of an individual species can be an indicator of health and whether optimal growth conditions (i.e. temperature, salinity and food availability) prevail. Over evolutionary timescales, individuals tend to increase in size (Cope&#8217;s rule) also altering the average size of the population.The Pliocene provides an excellent opportunity to look at environmental drivers and ecological responses to a warmer world, at high resolution and with extant species. A short glaciation phase, during marine isotope stage (MIS) M2, interrupted the Pliocene global warming between ~ 3.31 &#8211; 3.26 Ma. This event provides the ideal framework to quantify how biota, already adapted to warming conditions, respond to a short, but substantial cooling event.&#160;We analysed the size and species composition of samples collected as part of the Pliocene Research, Interpretation and Synoptic Mapping (PRISM) Project from a variety of locations around the globe. The samples cover the Atlantic, Indian and Pacific oceans at a range of latitudes (e.g. DSDP Site 521, 586, 607 and ODP Site 716, 754, 887). We measured the maximum diameter of planktonic foraminifera tests with a fully automated light microscope, enabling high resolution sampling at a multitude of sites, before, during and after the MIS M2 glaciation event. On average 2000 specimens were measured per sample, resulting in over a million analyses in total. Changes in planktonic foraminiferal assemblage composition were characterised by quantifying relative species abundances and augmented by determining the largest species.Planktonic foraminiferal assemblage size shows a general increase during the Pliocene likely related to warming temperatures. What is unclear is if this change is driven by changes in diversity due to extinction and origination, responses to environmental change or a general increase in size of species found through the record. Here we discuss reactions of species and (or) ecological groups to environmental change and determine the individual drivers of size change across the world&#8217;s oceans.

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Temporal variability of a protected multispecific tropical seagrass meadow in response to environmental change

Environmental Monitoring and Assessment ◽

10.1007/s10661-019-7977-z ◽

2019 ◽

Vol 191 (12) ◽

Author(s):

E. Alonso Aller ◽

J. S. Eklöf ◽

M. Gullström ◽

U. Kloiber ◽

H. W. Linderholm ◽

...

Keyword(s):

Species Composition ◽

Environmental Change ◽

Low Income ◽

Environmental Variables ◽

Seagrass Meadow ◽

Spatial Scales ◽

Temporal Changes ◽

Climate Impacts ◽

Seagrass Meadows ◽

Seagrass Cover

AbstractIn a changing environment, there is an increasing interest to monitor ecosystems to understand their responses to environmental change. Seagrass meadows are highly important ecosystems that are under constant pressure from human activities and climate impacts, with marked declines observed worldwide. Despite increasing efforts, monitoring of multispecific tropical seagrass meadows is scarce, particularly in low-income regions. Based on data from a monitoring programme in a marine protected area in Zanzibar (Tanzania), we assessed temporal changes in seagrass cover and species composition during a 10-year period in relation to local variability in environmental variables. We observed a strong, gradual decline in seagrass cover and changes in species composition, followed by a period of recovery. However, the timing and length of these temporal patterns varied in space (between transects). Multiple environmental variables—cloud cover, temperature, storm occurrence, sunspot activity, and tidal amplitude and height—influenced seagrass cover, although only to a minor extent, suggesting that the monitored seagrass meadow may be influenced by other unmeasured factors (e.g. water currents and sediment movement). Our results show that seagrass meadows can be highly dynamic at small (10–50 m) spatial scales, even in the absence of major local anthropogenic impacts. Our findings suggest that high-resolution monitoring programmes can be highly valuable for the detection of temporal changes in multispecific seagrass meadows; however, to understand the causes of change, there is a need of long-term (> 10 years) data series that include direct measurements of environmental variables and extreme events.

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Plant species composition shifts in the Tatra Mts as a response to environmental change: a resurvey study after 90 years

Folia Geobotanica ◽

10.1007/s12224-018-9312-9 ◽

2018 ◽

Vol 53 (3) ◽

pp. 333-348 ◽

Cited By ~ 10

Author(s):

Patryk Czortek ◽

Jutta Kapfer ◽

Anna Delimat ◽

Amy Elizabeth Eycott ◽

John-Arvid Grytnes ◽

...

Keyword(s):

Species Composition ◽

Environmental Change ◽

Plant Species ◽

Plant Species Composition ◽

Tatra Mts ◽

Response To Environmental Change

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Forest Transformation Urgency for Topsoil Diversity Optimization During Environmental Change

Journal of Landscape Ecology ◽

10.2478/jlecol-2020-0018 ◽

2020 ◽

Vol 0 (0) ◽

Author(s):

Pavel Samec ◽

Miloš Zapletal ◽

Matěj Horáček

Keyword(s):

Species Composition ◽

Environmental Change ◽

Tree Species ◽

Residue Analysis ◽

Forest Tree ◽

Tree Species Composition ◽

Sulphur Deposition ◽

Soil Diversity ◽

Forest Tree Species ◽

Forest Transformation

AbstractCombined effect of environmental change and management variability leads to reduced soil diversity in homogenous forest stands. On the other hand, forest soil diversity is maintained with rich tree species composition. In this study, focus has been put on deriving urgency to change forest tree species composition in order to increase soil diversity in biogeographic regions with uneven impact of environmental change. The relation of forest tree species and soil diversities was compared between the periods of dominant sulphur deposition (1985–1994) and the period of regional environmental change (2003–2012) in the Czech Republic (Central Europe; 78 866 km2; 115–1602 m n.m.). Forest tree species and soil diversities were assessed using linear regression, discrimination analysis and geographically weighted regression including residue analysis. The effect of spatial differences of acid deposition on soil properties, though, decreased, still dependencies between the diversity of bedrock, soils and forest tree species increased significantly. Only 12.9 % of forests in the territory of the CR have optimum tree species diversity. The total of 65.9 % of forest require highly or moderately urgent transformation. An increase in spatial dependencies between soil and tree species diversities confirms the importance of site differentiation in forest transformation.

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