Seasonal Variation in Trophic Diversity and Relative Importance of Basal Resources Supporting Tropical River Fish Assemblages in Chiapas, Mexico

2020 ◽  
Vol 149 (6) ◽  
pp. 753-769
Author(s):  
Allison A. Pease ◽  
Miriam Soria‐Barreto ◽  
Alfonso A. González‐Díaz ◽  
Rocío Rodiles‐Hernández
Keyword(s):  
Seasonal Variation ◽  
Fish Assemblages ◽  
Relative Importance ◽  
Tropical River ◽  
Trophic Diversity ◽  
Basal Resources ◽  
River Fish

Spatial and seasonal variation in littoral fish assemblages of four estuarine lagoons on the Mexican Pacific coast

2021 ◽  
pp. 102000
Author(s):  
Yureidy Cabrera-Páez ◽  
Consuelo M. Aguilar-Betancourt ◽  
Gaspar González-Sansón ◽  
Angel Hinojosa-Larios
Keyword(s):  
Seasonal Variation ◽  
Pacific Coast ◽  
Fish Assemblages ◽  
Mexican Pacific ◽  
Littoral Fish ◽  
Spatial And Seasonal Variation

Historical Changes in Large River Fish Assemblages of the Americas

2005 ◽  
Keyword(s):  
New York ◽  
Dreissena Polymorpha ◽  
Native Species ◽  
Environmental Changes ◽  
Fish Assemblages ◽  
Hudson River ◽  
Osmerus Mordax ◽  
Shoreline Development ◽  
Rainbow Smelt ◽  
River Fish

<em>Abstract.</em>—The main channel of the Hudson River is a tidal estuary from its mouth in New York Harbor to Troy, New York, 247 km upstream. It drains about 35,000 km<sup>2</sup> and is an important navigational, commercial, and recreational system. Since the arrival of European settlers over 400 years ago, it has undergone numerous environmental changes. These changes have included channel maintenance by dredging, wholesale dumping of industrial and domestic wastes, scattered in-basin urbanization and shoreline development, deforestation of the watershed and an increase in agriculture, and water removal for commercial, industrial, and agricultural needs. In addition, the biota of the river has supported commercial and recreational harvesting, exotic species have become established, and habitats have become fragmented, replaced, changed in extent, or isolated. The tidal portion of the Hudson River is among the most-studied water bodies on Earth. We use data from surveys conducted in 1936, the 1970s, the 1980s, and the 1990s to examine changes in fish assemblages and from other sources dating back to 1842. The surveys are synoptic but use a variety of gears and techniques and were conducted by different researchers with different study goals. The scale of our assessment is necessarily coarse. Over 200 species of fish are reported from the drainage, including freshwater and diadromous species, estuarine forms, certain life history stages of primarily marine species, and marine strays. The tidal Hudson River fish assemblages have responded to the environmental changes of the last century in several ways. Several important native species appear to be in decline (e.g., rainbow smelt <em>Osmerus mordax </em>and Atlantic tomcod <em>Microgadus tomcod</em>), others, once in decline, have rebounded (e.g., striped bass <em>Morone saxatilis</em>), and populations of some species seem stable (e.g., spottail shiner <em>Notropis hudsonius</em>). No native species is extirpated from the system, and only one, shortnose sturgeon <em>Acipenser brevirostrum</em>, is listed as endangered. The recent establishment of the exotic zebra mussel <em>Dreissena polymorpha </em>may be shifting the fish assemblage away from openwater fishes (e.g., <em>Alosa</em>) and toward species associated with vegetation (e.g., centrarchids). In general, the Hudson River has seen an increase in the number and importance of alien species and a change in dominant species.

scholarly journals Space Is More Important than Season when Shaping Soil Microbial Communities at a Large Spatial Scale

mSystems ◽  
2020 ◽  
Vol 5 (3) ◽  
Author(s):  
Kaoping Zhang ◽  
Manuel Delgado-Baquerizo ◽  
Yong-Guan Zhu ◽  
Haiyan Chu
Keyword(s):  
Seasonal Variation ◽  
Microbial Community ◽  
Spatial Scale ◽  
Environmental Variables ◽  
Soil Microbial Communities ◽  
Spatiotemporal Variation ◽  
Relative Importance ◽  
Large Spatial Scale ◽  
Environmental Covariates ◽  
Soil Microbial

ABSTRACT The relative importance of spatial and temporal variability in shaping the distribution of soil microbial communities at a large spatial scale remains poorly understood. Here, we explored the relative importance of space versus time when predicting the distribution of soil bacterial and fungal communities across North China Plain in two contrasting seasons (summer versus winter). Although we found that microbial alpha (number of phylotypes) and beta (changes in community composition) diversities differed significantly between summer and winter, space rather than season explained more of the spatiotemporal variation of soil microbial alpha and beta diversities. Environmental covariates explained some of microbial spatiotemporal variation observed, with fast-changing environmental covariates—climate variables, soil moisture, and available nutrient—likely being the main factors that drove the seasonal variation found in bacterial and fungal beta diversities. Using random forest modeling, we further identified a group of microbial exact sequence variants (ESVs) as indicators of summer and winter seasons and for which relative abundance was associated with fast-changing environmental variables (e.g., soil moisture and dissolved organic nitrogen). Together, our empirical field study’s results suggest soil microbial seasonal variation could arise from the changes of fast-changing environmental variables, thus providing integral support to the large emerging body of snapshot studies related to microbial biogeography. IMPORTANCE Both space and time are key factors that regulate microbial community, but microbial temporal variation is often ignored at a large spatial scale. In this study, we compared spatial and seasonal effects on bacterial and fungal diversity variation across an 878-km transect and found direct evidence that space is far more important than season in regulating the soil microbial community. Partitioning the effect of season, space and environmental variables on microbial community, we further found that fast-changing environmental factors contributed to microbial temporal variation.

Relative importance of local and landscape variables on fish assemblages in streams of Brazilian savanna

2019 ◽  
Vol 26 (2) ◽  
pp. 119-130 ◽  
Author(s):  
Hugo de Oliveira Barbosa ◽  
Pedro Paulino Borges ◽  
Renato Bolson Dala-Corte ◽  
Patrick Thomaz de Aquino Martins ◽  
Fabrício Barreto Teresa
Keyword(s):  
Fish Assemblages ◽  
Brazilian Savanna ◽  
Relative Importance ◽  
Landscape Variables

scholarly journals The epidemiology of rubella in Mexico: seasonality, stochasticity and regional variation

2010 ◽  
Vol 139 (7) ◽  
pp. 1029-1038 ◽  
Author(s):  
C. J. E. METCALF ◽  
O. N. BJØRNSTAD ◽  
M. J. FERRARI ◽  
P. KLEPAC ◽  
N. BHARTI ◽  
...  
Keyword(s):  
Seasonal Variation ◽  
North America ◽  
Regional Variation ◽  
Stochastic Dynamics ◽  
Temporal Dynamics ◽  
Relative Importance ◽  
Annual Cycles ◽  
Congenital Rubella ◽  
Age Of Infection ◽  
Lines Of Evidence

SUMMARYThe factors underlying the temporal dynamics of rubella outside of Europe and North America are not well known. Here we used 20 years of incidence reports from Mexico to identify variation in seasonal forcing and magnitude of transmission across the country and to explore determinants of inter-annual variability in epidemic magnitude in rubella. We found considerable regional variation in both magnitude of transmission and amplitude of seasonal variation in transmission. Several lines of evidence pointed to stochastic dynamics as an important driver of multi-annual cycles. Since average age of infection increased with the relative importance of stochastic dynamics, this conclusion has implications for the burden of congenital rubella syndrome. We discuss factors underlying regional variation, and implications of the importance of stochasticity for vaccination implementation.

Fish assemblages in coastal lagoons in land-uplift succession: The relative importance of local and regional environmental gradients

2009 ◽  
Vol 81 (2) ◽  
pp. 247-256 ◽  
Author(s):  
Martin Snickars ◽  
Alfred Sandström ◽  
Antti Lappalainen ◽  
Johanna Mattila ◽  
Kajsa Rosqvist ◽  
...  
Keyword(s):  
Fish Assemblages ◽  
Environmental Gradients ◽  
Coastal Lagoons ◽  
Relative Importance ◽  
Land Uplift

scholarly journals Bony fish bycatch in the southern Brazil pink shrimp (Farfantepenaeus brasiliensis and F. paulensis) fishery

2005 ◽  
Vol 48 (4) ◽  
pp. 611-623 ◽  
Author(s):  
Marcelo Vianna ◽  
Tabajara Almeida
Keyword(s):  
Seasonal Variation ◽  
Coastal Water ◽  
Critical Period ◽  
Fish Assemblages ◽  
Bony Fish ◽  
Water Masses ◽  
Southern Brazil ◽  
Pink Shrimp ◽  
Bony Fishes ◽  
Homogenous Distribution

Trawling for pink shrimp (Farfantepenaeus brasiliensis and F. paulensis) catches also large quantities of fish, mostly bony fish, which are discarded, as they have no commercial value. Their composition and abundance were studied in an area that corresponded to the southeastern coastline of Brazil. Ninety one species were registered. Incidental fishing affected mainly small individuals and occured throughout the year. The year round rate of bony fish to shrimp catches was 10,5:1,0. Three assemblages of bony fishes could be identified, influenced by the seasonal variation of the water masses, the predominant group being associated with the Coastal Water, another with the penetration of colder waters onto the platform (SACW) and a third group of a more homogenous distribution. The most critical period identified for the bycatch capture was the beginning of the winter, which was due to the overlapping of fish assemblages and the peak of fishing recruitment.

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