scholarly journals Un caso de éxito en la restauración de un humedal tropical mediante la evaluación del ensamble de larvas de Odonata (Insecta)

2015 ◽  
Vol 63 (4) ◽  
pp. 1043 ◽  
Author(s):  
José Antonio Gómez-Anaya ◽  
Rodolfo Novelo-Gutiérrez
Keyword(s):  
Reference Site ◽  
Numerical Study ◽  
Species Abundance ◽  
Species Number ◽  
Larval Abundance ◽  
Dominance Order ◽  
Plant Structure ◽  
Species Dominance ◽  
La Mancha ◽  
Dry And Rainy Seasons

<strong>Abstract. A case of successful restoration of a tropical wetland evaluated through its Odonata (Insecta) larval assemblage. </strong>This article provides numerical study of the Odonata larvae from a tropical recovered wetland located in La Mancha (LM, Ramsar site 1336), Veracruz, Mexico. Larval surveys were performed during the dry and rainy seasons of 2010 and 2011 and compared to a reference site in the locality of Cansaburro (CB). The effect of site, season and year on Odonata larval abundance was explored and diversity, richness, evenness and abundance distributions of both assemblages were compared. A total of 3,718 larvae from 25 species (five Zygoptera and 20 Anisoptera) in 14 genera and three families were collected from both wetlands. Species number was equal to both wetlands although abundance was significantly higher in LM. Diversity and species abundance patterns in both sites were similar although Shannon diversity was significant and slightly higher in the reference site. Differences in species composition and species dominance order between both assemblages were observed and addressed to differences in the aquatic plant structure between both wetlands which is mainly affected by management in La Mancha and by cattle grazing in Cansaburro. While the diversity of La Mancha was lesser than the reference site, most of the results of this investigation showed that La Mancha wetland has been successfully recovered.

scholarly journals Year-to-year crop shifts promote weed diversity in tropical permanent rainfed cultivation

2020 ◽  
Author(s):  
Margot Neyret ◽  
Anneke de Rouw ◽  
Nathalie Colbach ◽  
Henri Robain ◽  
Bounsamay Soulileuth ◽  
...  
Keyword(s):  
Upland Rice ◽  
Centella Asiatica ◽  
Shannon Index ◽  
Species Number ◽  
List Type ◽  
Herbaceous Species ◽  
Frequent Change ◽  
Young Tree ◽  
Species Dominance ◽  
Density And Biomass

AbstractIn the past decades, the expansion and modernisation of agriculture in the mountainous areas of Southeast Asia has had severe impacts on biodiversity, as the once species-rich forests were turned into homogeneous fields receiving ample external inputs. A common feature of permanent cropping with annual crops is the frequent change of crop choice, depending on market opportunities or other motives. However, the precise effect of crop shifts on weeds in tropical areas is largely unknown. In this study, we investigated the short-term effect of crop sequences on the diversity of weed communities in smallholder fields in Northern Thailand. Crop choices were upland rice, maize, fallow and young tree plantations with or without intercrop. We counted the number of crop shifts and the number of crops involved during a 3-years period preceding weed sampling. We showed that the number of crop shifts did not affect weed density and biomass. However, herbaceous species number and diversity (measured as Shannon index) increased by 36% and 46% respectively, while herbaceous species dominance decreased by 38%, in fields with yearly crop shifts compared to fields with no shifts in the previous three years. The effect of a particular crop on diversity, or the effect of intercropping with young trees, was weaker. It was likely due to the more variable resources (especially light) in fields with two crop shifts, allowing species with different niches to co-exist. Crop type and frequent crop shifts did not affect shrub and tree species number, diversity or dominance. Some species were strongly associated with fields with no crop shift in the sequence (e.g. the tree Antidesma velutinosum) or to fields with two crop shifts in the sequence (e.g. the herb Centella asiatica, the C4 grass Digitaria radicosa). Overall, this study showed that in this agronomical system, maintaining yearly crop shifts does not significantly affect weed abundance, but supports in-field plant species diversity, which is likely to impact the services provisioned by tropical mountainous agro-ecosystemsHighlightsFrequent crop shifts in a crop sequence increased weed richness and diversity.Crop shifts had a stronger effect on weed richness and diversity than the current crop.The number of crop shifts did not affect weed biomass and density.Graphical abstract

scholarly journals Self–organized instability in complex ecosystems

2002 ◽  
Vol 357 (1421) ◽  
pp. 667-681 ◽  
Author(s):  
Ricard V. Solé ◽  
David Alonso ◽  
Alan McKane
Keyword(s):  
Rare Species ◽  
Scaling Law ◽  
Species Abundance ◽  
Field Studies ◽  
Species Number ◽  
Neotropical Forests ◽  
Species Abundances ◽  
Long Tails ◽  
Critical Boundary ◽  
Species Area

Why are some ecosystems so rich, yet contain so many rare species? High species diversity, together with rarity, is a general trend in neotropical forests and coral reefs. However, the origin of such diversity and the consequences of food web complexity in both species abundances and temporal fluctuations are not well understood. Several regularities are observed in complex, multispecies ecosystems that suggest that these ecologies might be organized close to points of instability. We explore, in greater depth, a recent stochastic model of population dynamics that is shown to reproduce: (i) the scaling law linking species number and connectivity; (ii) the observed distributions of species abundance reported from field studies (showing long tails and thus a predominance of rare species); (iii) the complex fluctuations displayed by natural communities (including chaotic dynamics); and (iv) the species–area relations displayed by rainforest plots. It is conjectured that the conflict between the natural tendency towards higher diversity due to immigration, and the ecosystem level constraints derived from an increasing number of links, leaves the system poised at a critical boundary separating stable from unstable communities, where large fluctuations are expected to occur. We suggest that the patterns displayed by species–rich communities, including rarity, would result from such a spontaneous tendency towards instability.

Benthic species as mud patrol - modelled effects of bioturbators and biofilms on large-scale estuarine mud and morphology

2021 ◽  
Author(s):  
Muriel Brückner ◽  
Christian Schwarz ◽  
Giovanni Coco ◽  
Anne Baar ◽  
Márcio Boechat Albernaz ◽  
...  
Keyword(s):  
Morphological Change ◽  
Species Interactions ◽  
Large Scale ◽  
Habitat Degradation ◽  
Species Abundance ◽  
Estuarine Sediments ◽  
Morphological Development ◽  
Benthic Species ◽  
Species Dominance ◽  
Species Specific

&lt;p&gt;Benthic species that live within estuarine sediments stabilize or destabilize local mud deposits through their eco-engineering activities, affecting the erosion of intertidal sediments. Possibly, the altered magnitudes in eroded sediment affect the large-scale redistribution of fines and hence morphological change. To quantify this biological control on the morphological development of estuaries, we numerically model i) biofilms, ii) two contrasting bioturbating species present in NW-Europe, and iii) their combinations by means of our novel eco-morphodynamic model. The model predicts local mud erodibility based on species pattern, which dynamically evolves from the hydrodynamics, soil mud content, competition and grazing, and is fed back into the hydromorphodynamic computations.&lt;/p&gt;&lt;p&gt;We find that biofilms reduce mud erosion on intertidal floodplains and stabilize estuarine morphology, whereas the two bioturbators significantly enhance inter- and supratidal mud erosion and bed elevation change, leading to a large-scale reduction in deposited mud and a widening of the estuary. In turn, the species-dependent changes in mud content redefines their habitat and leads to a redistribution of species abundances. Here, the eco-engineering affects habitat conditions and species abundance while species interactions determine species dominance. Our results show that species-specific biostabilization and bioturbation determine large-scale morphological change through mud redistribution, and at the same time affect species distribution. This suggests that benthic species have subtly changed estuarine morphology through space and time and that aggravating habitat degradation might lead to large effects on the morphology of future estuaries.&lt;/p&gt;

scholarly journals Species diversity of segetal communities in tuber crops and in winter and spring cereals

2013 ◽  
Vol 66 (3) ◽  
pp. 95-102
Author(s):  
Zofia Rzymowska ◽  
Maria Ługowska ◽  
Janina Skrzyczyńska
Keyword(s):  
Species Diversity ◽  
Species Abundance ◽  
Wiener Index ◽  
Species Number ◽  
Individual Species ◽  
Soil Conditions ◽  
Weed Communities ◽  
Spring Cereals ◽  
Dominance Indices ◽  
Tuber Crops

The work presents the results of studies on the diversity of weed communities in tuber crops as well as in winter and spring cereals under similar climatic and soil conditions. We examined overall species abundance in the groups analysed, the average species number per relevé, as well as weed cover of the study area. Additionally, species composition, number of individual species and their biomass were determined. Dominant species in each crop group were distinguished. Species diversity was determined based on the following ecological indices: the Shannon-Wiener index of biodiversity <em>H’</em> and Simpson’s index of dominance <em>C</em>. The indices were computed on the biomass and number-of-species basis. The objective of the work was to compare the structure and diversity of weed communities in the crops studied. The communities analysed differed in all the characteristics examined. Differences were found between biodiversity and dominance indices calculated for individual crop groups, but their significance depended on the method applied to calculate the indices.

scholarly journals The fish community of the Sorocaba River Basin in different habitats (State of São Paulo, Brazil)

2009 ◽  
Vol 69 (4) ◽  
pp. 1015-1025 ◽  
Author(s):  
WS. Smith ◽  
M. Petrere Jr. ◽  
W. Barrella
Keyword(s):  
River Basin ◽  
Fish Assemblage ◽  
Standard Length ◽  
Fish Community ◽  
Species Abundance ◽  
Sao Paulo ◽  
Abundance Distribution ◽  
Abiotic Variables ◽  
Species Abundance Models ◽  
Dry And Rainy Seasons

A fish assemblage study was accomplished in different habitats of the Sorocaba River Basin. Fish were caught with gillnets, were weighed (weight total - g) and measured (standard length - mm). Several abiotic variables of selected sampling sites were measured in order to characterise their habitats in order to attempt establishing correlations with fish community traits. Fish numbers per species were adjusted to the lognormal and logseries species/abundance models The fish community totaled 38 species, distributed in 28 genera, 14 families and 4 orders. Diversity was calculated both in number and in weight and both presented higher values in better preserved sites. We did not detect any statistical differences between dry and rainy seasons. We also concluded that the abundance distribution was not influenced by abiotic variables.

scholarly journals Development of Learning Media Based on Arthropoda (Crustacea) Filum Diversity in Kampai Island of SD Negeri 050778 Langkat District, Sumatera Utara

2019 ◽  
Vol 1 (5) ◽  
Author(s):  
Budianto Budianto ◽  
Pandu Prabowo Warsodirejo
Keyword(s):  
Science Teachers ◽  
Diversity Index ◽  
Descriptive Analysis ◽  
Species Abundance ◽  
Test Sample ◽  
Species Dominance ◽  
Mangrove Crab ◽  
Development Data ◽  
Pagurus Bernhardus ◽  
Development Methods

This study aims to develop learning media that can be used by natural science teachers in SD Negeri 050778 by referring to RND-based media development methods (Research and Development) which will later use descriptive analysis methods and development methods. In making Blended Learning media where this media is in the form of learning videos using the Camtasia and Wondershare Quiz Creator application contains recorded video clips and questions about how to sample species, species diversity, and species collection techniques from Phylum Arthropods at SD Negeri 050778 Kampai Langkat Island, North Sumatra. The purpose of this research is descriptive analysis which is to obtain data on the diversity of the Artrhopoda Phylum from the Crustacean class which is very numerous and easily found around the coast of the island of Kampai. Crustacean diversity data obtained were analyzed using species abundance analysis method. Then the learning video development data will then be tested on students and science teachers as a test sample. From the field results found 8 dominant species of the Decapoda Order, including the Mangrove Crab (Scylla serrate), tiger shrimp (Panaeus monodon), Lobster Shrimp (Panulirus sp.), Ghost Crab (Ocypode kuhlii), Crab Uca Viola (Uca vocans) , Uca Petarung Crab (Uca annulipes), Centipede Shrimp (Squilla mantis), Klomang (Bernhardus Pagurus). From the three stations where Crustacea species sampling locations were obtained a diversity index of 0.85% at Station 1 with Species dominance, namely Centipede Shrimp, then 1.76% at Station II with Species dominance, namely Klomang (Pagurus bernhardus), and 0 , 43% with species dominance, namely Shrimp Prawn (Panaeus monodoni). From the analysis calculations of 30 students the results of a large group trial for development data are: (a) a group of 30 students an average of 97.85% (very decent), (2) Science Teacher Test Data of 87% (feasible category).

Predation of larval benthic invertebrates in St George’s Bay, Nova Scotia

2012 ◽  
Vol 93 (3) ◽  
pp. 591-599 ◽  
Author(s):  
Jessie Short ◽  
Anna Metaxas ◽  
Rémi M. Daigle
Keyword(s):  
Nova Scotia ◽  
Water Column ◽  
Gasterosteus Aculeatus ◽  
Larval Mortality ◽  
Larval Survival ◽  
Gut Contents ◽  
Larval Abundance ◽  
Species Dominance ◽  
Merluccius Bilinearis ◽  
Larval Species

Larval survival during planktonic dispersal is crucial to the connectivity among benthic populations. Although predation has been suggested as an important cause of larval mortality, this process has rarely been quantified in the field. We measured the abundance of various larval species in the water column in St George’s Bay, Nova Scotia, Canada, on 3 different occasions in summer (August 2008, July and August 2009), the period of high larval abundance in our region. We sampled four numerically dominant predators (scyphozoans: Cyanea capillata and Aurelia aurita; fishes: Gasterosteus aculeatus and Merluccius bilinearis) and lobster larvae near the water surface with a neuston net and other larval species in the water column (3 m depth) with a ring net. Larvae found in the gut contents of the predators included various species of gastropods, crustaceans and bivalves, and these were more abundant in the scyphozoans than the fishes. We attribute these differences to variation in predation method. For certain larval taxa, we found significant differences between the proportional abundance in the guts of C. capillata and in the water column, indicating prey selectivity. This study evaluates the potential impact of predation on larval survival and indicates that the presence of predators can cause changes in abundance and consequent taxonomic shifts in species dominance of larvae, influencing their successful subsequent recruitment to the benthos.

Identification of the environmental factors which drive the botanical and functional composition of permanent grasslands

2011 ◽  
Vol 150 (2) ◽  
pp. 219-236 ◽  
Author(s):  
A. MICHAUD ◽  
S. PLANTUREUX ◽  
B. AMIAUD ◽  
P. CARRÈRE ◽  
P. CRUZ ◽  
...  
Keyword(s):  
Climatic Factors ◽  
Present Report ◽  
Floristic Composition ◽  
Matter Content ◽  
Species Number ◽  
Dry Matter Content ◽  
Functional Composition ◽  
Botanical Composition ◽  
Functional Characteristics ◽  
Species Dominance

SUMMARYManaged grasslands provide environmental and agronomic services that can be predicted from the botanical and functional composition of the vegetation. These are influenced by management, edaphic and climatic factors. The present report set out to estimate and analyse the relative importance of management, soil and climate factors on botanical and functional characteristics of grassland vegetation. A set of 178 French grasslands having a large pedoclimatic and management gradient was selected, and information collected on botanical composition, pedoclimatic factors and management. Six vegetation characteristics were considered: two botanical (floristic composition and species dominance) and four functional (proportion of entomophilous species, number of oligotrophic species, leaf dry matter content and date of flowering). First, the links between the characteristics of the vegetation were analysed to check for any redundancy among them; all were kept. Second, it was demonstrated that botanical and functional characteristics were not driven by the same factors: functional composition was characterized by management, edaphic and climatic factors, whereas botanical composition was influenced mainly by climatic and edaphic factors plus other factors. Interactions between factors also have to be taken into consideration to predict botanical and functional composition of grasslands. Functional and botanical characteristics of vegetation help to predict ecosystem services delivered by grasslands and may be used in combination.

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