scholarly journals Impact of weeds from field margins on adjacent agriculture land

2020 ◽  
Vol 72 (3) ◽  
pp. 403-411
Author(s):  
Edita Stefanic ◽  
Slavica Antunovic ◽  
Vesna Kovacevic ◽  
Alka Turalija ◽  
Dinko Zima
Keyword(s):  
Diversity Index ◽  
Distribution Patterns ◽  
Ambrosia Artemisiifolia ◽  
Field Margins ◽  
Field Margin ◽  
Row Crops ◽  
Arable Farming ◽  
Adjacent Field ◽  
Crop Area ◽  
Sowing Season

A vegetation survey in northeastern Croatia explored the influence of intensive arable farming on the weed community in relation to the crop edge and adjacent field margin. A total of 141 vascular plants were recorded, and significant differences among the species appear in the field margins (134) as compared to the crop edges (109) and middle of the fields (49). Native plants predominated (83.7%), but among non-natives, the most abundant were Ambrosia artemisiifolia L., Abutilon theoprasti Med. and Veronica persica Poir., with the highest cover values inside the cropped areas, particularly during spring sowing of row crops. The most diverse (having significantly higher Evenness and Shannon?s diversity index) was the community from the field margin, followed by the weed community that developed on the crop edges. Three distribution patterns were observed: weeds typically limited to the crop area, weeds limited to the non-crop area and weeds with some ability to spread from the field margins. Major variations in species composition were identified according to sowing season and crop type. Wind dispersal annuals with light- and nitrogen-demands were associated with disturbed, tilled habitats, while perennials with higher requirements for moisture and other than a wind mode of dispersal, were associated with the field margins.

scholarly journals Sea cucumber community in the coastal area of the Bahoi Village,West Likupang Sub-district, North Minahasa District

2020 ◽  
Vol 8 (1) ◽  
pp. 37
Author(s):  
Andia Tri Fritama Lumbu ◽  
Lawrence J. L. Lumingas ◽  
Gaspar D. Manu
Keyword(s):  
Sea Cucumber ◽  
Diversity Index ◽  
Similarity Index ◽  
Sampling Technique ◽  
Distribution Patterns ◽  
Line Transect ◽  
Dominance Index ◽  
Holothuria Scabra ◽  
Research Site ◽  
Holothuria Atra

This research is conducted in the coastal waters of Bahoi Village, West Likupang Sub-district, North Minahasa District with the aims to know the types of sea-related environmental factors in the research site and know the community structure of the sea cucumber including the density, Index of diversity, dominance index, and distribution patterns. Data collection was done by using the line transect method, and sampling technique by using quadrat. The results of the study found 5 species of sea cucumber i.e. Holothuria atra,  Holothuria scabra,  Bohadschia marmorata, Actinopyga echinites, and  Bohadschia vitiensis. The individual density of all species is 0.12 ind/m2, and the diversity index (H ') 0.950. The value of the similarity index/compatibility obtained is e = 0.918. The result of the calculated dominance index of sea cucumber species is 1.0 and the pattern of spreading species of sea cucumber in the research site shows a random spread pattern because the value of dispersion index  (I) approaches 1 (one). Keywords: community; Sea cucumber; Bahoi; Dominance; Diversity.AbstrakPenelitian ini dilakukan di perairan pantai desa Bahoi, Kecamatan Likupang Barat, Kabupaten Minahasa Utara dengan tujuan untuk mengetahui jenis-jenis teripang yang ada di lokasi penelitian dan mengetahui struktur komunitas teripang yang meliputi kepadatan, indeks keanekaragaman, indeks dominasi, dan pola penyebaran. Pengambilan data dilakukan dengan metode line transek, dan teknik pengambilan sampel dengan mengunakan kuadrat. Hasil penelitian ditemukan 5 spesies teripang yaitu Holothuria atra, Holothuria scabra, Bohadschia marmorata, Actinopyga echinites dan Bohadschia vitiensis. Kepadatan individu dari seluruh spesies yaitu 0,12 ind/m2, indeks keanekaragaman (H’) 0,950. Nilai indeks kemerataan/keserasian diperoleh nilai indeks e = 0,918. nilai indeks dominasi spesies teripang diperoleh 1,0 dan pola penyebaran spesies teripang dilokasi penelitian menunjukkan pola sebaran acak (random) dikarenakan nilai indeks dispersi (I) mendekati 1 (satu).Kata Kunci : Komunitas; Teripang; Perairan Bahoi; Dominasi; Keanekaragaman

scholarly journals Invertebrates and vegetation of field margins adjacent to crops subject to contrasting herbicide regimes in the Farm Scale Evaluations of genetically modified herbicide–tolerant crops

2003 ◽  
Vol 358 (1439) ◽  
pp. 1879-1898 ◽  
Author(s):  
◽  
D. B. Roy ◽  
D. A. Bohan ◽  
A. J. Haughton ◽  
M. O. Hill ◽  
...  
Keyword(s):  
Oilseed Rape ◽  
Genetically Modified ◽  
Plant Cover ◽  
The Other ◽  
Spray Drift ◽  
Field Margins ◽  
Herbicide Tolerant ◽  
Adjacent Field ◽  
Farm Scale ◽  
The Difference

The effects of management of genetically modified herbicide–tolerant (GMHT) crops on adjacent field margins were assessed for 59 maize, 66 beet and 67 spring oilseed rape sites. Fields were split into halves, one being sown with a GMHT crop and the other with the equivalent conventional non–GMHT crop. Margin vegetation was recorded in three components of the field margins. Most differences were in the tilled area, with fewer smaller effects mirroring them in the verge and boundary. In spring oilseed rape fields, the cover, flowering and seeding of plants were 25%, 44% and 39% lower, respectively, in the GMHT uncropped tilled margins. Similarly, for beet, flowering and seeding were 34% and 39% lower, respectively, in the GMHT margins. For maize, the effect was reversed, with plant cover and flowering 28% and 67% greater, respectively, in the GMHT half. Effects on butterflies mirrored these vegetation effects, with 24% fewer butterflies in margins of GMHT spring oilseed rape. The likely cause is the lower nectar supply in GMHT tilled margins and crop edges. Few large treatment differences were found for bees, gastropods or other invertebrates. Scorching of vegetation by herbicide–spray drift was on average 1.6% on verges beside conventional crops and 3.7% beside GMHT crops, the difference being significant for all three crops.

Dominant diatom species in the Canada Basin in summer 2003, a reported serious melting season

Polar Record ◽  
2010 ◽  
Vol 47 (3) ◽  
pp. 244-261 ◽  
Author(s):  
Shuxian Zheng ◽  
Guizhong Wang ◽  
Fang Zhang ◽  
Minghong Cai ◽  
Jianfeng He
Keyword(s):  
Diversity Index ◽  
Algal Species ◽  
Ice Cores ◽  
Distribution Patterns ◽  
Canada Basin ◽  
Algal Community ◽  
The Arctic ◽  
Species Number ◽  
Diatom Species ◽  
Order Of Magnitude

ABSTRACTDuring the second Chinese National Arctic Research Expedition in summer 2003, sea ice cores and the underlying water were sampled from seven stations in the pack ice zone of the Canada Basin and were examined with a phase contrast microscope. A total of 102 and 78 algal species were identified for the ice cores and the underlying water, respectively, ranking in the middle range among the surveys of the Arctic Ocean up to the present despite seasonal variability. The Shannon-Wiener indices ranged from 1.40 to 4.88 with an average of 3.58 ± 0.68. Diatom species, especially pennate species, dominated in all the samples. A large number of algal spores were contained in every layer (abundance percentage > 1%). The microalgal abundances ranged from 1.4 × 104 to 8.73 × 105 cells L−1 and the biomass ranged from 0.56 to 89.49 μg L−1. They were correlated with the number of algal species (P < 0.05) but not with the diversity index (P > 0.05). Ice algal maxima were observed in various layers (bottom, interior and near the surface of the ice floes). The phytoplankton biomass in the ice-water interface was one order of magnitude lower than that in the bottom ice (P < 0.05). The species number and the diversity index in water samples, with much less biomass (P < 0.01), were comparative with the ice samples (P > 0.05). Spatial heterogeneity in both horizontal and vertical directions was the main characteristic of the algal community structure, which was demonstrated by the cluster analysis result and the distribution patterns.

scholarly journals Cyanobacteria bloom: selective filter for zooplankton?

2015 ◽  
Vol 75 (1) ◽  
pp. 165-174 ◽  
Author(s):  
NAST Mello ◽  
PM Maia-Barbosa
Keyword(s):  
Species Composition ◽  
Hydrological Cycle ◽  
Diversity Index ◽  
Zooplankton Community ◽  
Distribution Patterns ◽  
Distinct Species ◽  
Zooplankton Community Structure ◽  
Β Diversity ◽  
Cyanobacteria Blooms ◽  
The Stability

The Ibirité reservoir is an urban and eutrophic environment, with regular occurrences of cyanobacteria blooms. The reservoir is warm monomict and remains stratified most of the year, circulating in the dry season (winter). During the hydrological cycle of October/07 to October/08 there were four scenarios with different environmental conditions, which influenced the structure of the zooplankton community, as confirmed in a previous study. Changes in the zooplankton community structure between the scenarios were studied, aiming at analyzing the stability and persistence of this community. The Spearman’s coefficient of correlation was used to measure the stability; the persistence was evaluated through a cluster analysis and changes in community composition were estimated by the "temporal" β diversity index. Considering the distribution patterns of abundance, the community was stable only in the transition between scenarios 1 and 2 (n = 30, r = 0.71, p = 0.00001), when there were no cyanobacteria blooms. The persistence of zooplankton between the scenarios was low, showing a distinct species composition for each scenario. The highest variations in species composition, observed by the values of temporal β diversity index, were the transitions between scenarios 3-0 (1.45) and 0-1 (1.05), and the lowest variations occurred in the transition between scenarios 1-2 (0.57). The results suggest that the cyanobacteria blooms at Ibirité reservoir are be acting as "selective filters", and are, thus, disturbances with sufficient ability to change the structure of the zooplankton community. Keywords Urban Reservoir, zooplankton, bloom of cyanobacteria, stability, persistence.

scholarly journals Crop and Non-Crop Plants as Potential Reservoir Hosts of Alfalfa mosaic virus and Cucumber mosaic virus for Spread to Commercial Snap Bean

Plant Disease ◽  
2012 ◽  
Vol 96 (4) ◽  
pp. 506-514 ◽  
Author(s):  
E. E. Mueller ◽  
R. L. Groves ◽  
C. Gratton
Keyword(s):  
Cucumber Mosaic Virus ◽  
Mosaic Virus ◽  
Alfalfa Mosaic Virus ◽  
Inoculum Potential ◽  
Field Margins ◽  
Snap Bean ◽  
Virus Incidence ◽  
Potential Reservoir ◽  
Adjacent Field ◽  
Project Objectives

Diseases caused by aphid-transmitted viruses such as Alfalfa mosaic virus (AMV) and Cucumber mosaic virus (CMV) have increased in snap bean (Phaseolus vulgaris) in the Midwestern United States. Plants immediately surrounding agricultural fields may serve as primary virus inocula for aphids to acquire and transmit to bean crops. The project objectives were to (i) identify potentially important AMV and CMV reservoirs among naturally infected plants and (ii) determine the relationship between the virus inoculum potential (VIP) in adjacent crop field margins and virus incidence in P. vulgaris. From 2006 to 2008, surveys were conducted to quantify the virus incidence and percentage cover (2008 only) of plants present within 5 m of the P. vulgaris crop. In all, 4,350 individual plants representing 44 species were assayed, with overall AMV and CMV incidences averaging 12 and 1.5%, respectively. A VIP index was developed and used to rank the importance of virus-susceptible plants in adjacent field margins. The overall VIP index for AMV in field margins was weakly associated with AMV incidence in P. vulgaris and no relationship was observed between local CMV inoculum and P. vulgaris incidence, suggesting that factors additional to local inoculum sources may influence CMV epidemics in P. vulgaris.

scholarly journals Taxon-specific temporal shifts in pollinating insects in mass-flowering crops and field margins in Ireland

2021 ◽  
Vol 28 ◽  
pp. 90-107
Author(s):  
Irene Bottero ◽  
Simon Hodge ◽  
Jane Stout
Keyword(s):  
Agricultural Landscapes ◽  
Floral Resources ◽  
Field Margins ◽  
Flowering Period ◽  
Field Margin ◽  
Mass Flowering ◽  
Insect Abundance ◽  
Insect Pollinators ◽  
Pollinating Insects ◽  
Hover Flies

In intensively cropped agricultural landscapes, the vegetation in edges and hedges (henceforth “field margins”) represents an important semi-natural habitat providing fundamental resources for insect pollinators. We surveyed the pollinating insects associated with two mass-flowering crops, apple and oilseed rape, and compared the insect fauna of the main crop with that in the field margins in the grass-dominated agricultural landscapes of Ireland. Different insect groups responded differently to the presence of the flowering crop, with honey and bumble bees more abundant in crops than margins during crop flowering, but more hover flies and butterflies in margins throughout. The composition of the insect assemblage also shifted over time due to taxon-specific changes in abundance. For example, solitary bees were most abundant early in the season, whereas hover flies peaked, and butterflies declined, in mid-summer. The temporal shift in insect community structure was associated with parallel changes in the field margin flora, and, although we found no relationship between insect abundance and abundance of field margin flowers, Bombus abundance and total insect abundance were positively correlated with floral diversity. After the crop flowering period, floral abundance and diversity was maintained via margin plants, but by late summer, floral resources declined. Our results confirm the importance of field margins for insect pollinators of entomophilous crops set within grass-dominated landscapes, even during the crop flowering period, and provide additional support for agri-environment schemes that protect and/or improve field margin biodiversity. The results also demonstrate that although shifts in insect and plant communities may be linked phenologically there may not always be simple relationships between insect and floral abundance and richness. 

scholarly journals Landscape distribution of oribatid mites (Acari, Oribatida) in Kolkheti National Park (Georgia, Caucasus)*

Zoosymposia ◽  
2011 ◽  
Vol 6 (1) ◽  
pp. 221-233 ◽  
Author(s):  
MAKA MURVANIDZE ◽  
LEVAN MUMLADZE ◽  
TEA ARABULI ◽  
ERISTO KVAVADZE
Keyword(s):  
National Park ◽  
Diversity Index ◽  
Sand Dunes ◽  
Oribatid Mite ◽  
Distribution Patterns ◽  
Oribatid Mites ◽  
Species Number ◽  
Humid Forest ◽  
Mite Communities ◽  
Specific Species

The key subject of this investigation was to study distribution patterns of oribatid mites in the main habitats and ecosystems of Kolkheti National Park. Oribatida were studied in 1) sand dunes, 2) Juncus bogs, 3) flooded alder (Alnus barbata C. A. Mey) forests, and 4) humid alder forests. Sampling was conducted in November 2009 at 18 sites along three transects. For exploratory analysis, we applied clustering techniques. Correlation between species number, density and humus was calculated. Chao1 statistics were used to estimate the completeness of sampling. Forty six oribatid species were recorded. The highest Shannon diversity index was registered for alder forests, whereas the lowest index was observed for dunes. In sand dunes 16 species were found, three of which occurred only in this landscape. In Juncus bogs, 32 species were recorded, and 16 were unique to this landscape, including bog specific Zetomimus furcatus (Warburton & Pearce, 1905), Euzetes globulus (Nicolet, 1855) and Punctoribates manzanoensis Hammer, 1958. Twenty two species were found in flooded forests, seven being exclusive. Ten species were recorded in humid forests, and Metabelbella macerochaeta Bulanova-Zachvatkina, 1965 and Eremobelba geographica Berlese, 1908, typical inhabitants of humid forest soils, appeared as exclusive species. Faunal comparisons among landscapes show high similarity between dune and bog oribatid mite communities, followed by flooded and humid alder forests. In dunes and bogs, total faunal density is determined by euryecological species, whereas in alder forests density was determined by high abundance of humid and extremely humid specific species.

Soil microbial functional diversity along an elevation gradient in Northwestern Caucasus

2020 ◽  
Author(s):  
Kristina Ivashchenko ◽  
Alexandra Seleznyova ◽  
Sofia Sushko ◽  
Anna Zhuravleva ◽  
Alexander Tronin ◽  
...  
Keyword(s):  
Functional Diversity ◽  
Plant Diversity ◽  
Altitudinal Gradient ◽  
Diversity Index ◽  
Elevation Gradient ◽  
Distribution Patterns ◽  
Microbial Functional Diversity ◽  
Soil Microbial ◽  
Northwestern Caucasus ◽  
Edaphic Properties

&lt;p&gt;In contrast to taxonomic diversity of soil microbiome, the distribution patterns of functional diversity for various ecosystems, including along an altitudinal gradient, is poorly understood. Consequently, the study focuses on finding out the spatial distribution features of microbial functional diversity in mountainous soils along elevation through forests and meadows ecosystems. We hypothesized that soil microbial functional diversity is increasing along the altitudinal gradient in conjunction with plant diversity. In Northwestern Caucasus (Karachay-Cherkess Republic, Russia) the north-eastern mountain slope was studied across mixed, fir and deciduous forests, subalpine and alpine meadows located from 1260 to 2480 m above sea level. Twelve plots (0.25 m&lt;sup&gt;2&lt;/sup&gt; each) were randomly chosen within each ecosystem (total 60). Plant species composition and Shannon plant diversity index (H) were assessed for the plots. Topsoil samples (0-10 cm) were taken from the plots in August for assessment microbial functional diversity through community level physiological profile (CLPP). It was determined by microbial respiration response on amino, carboxylic, phenolic acids and carbohydrates (MicroResp). Shannon's functional diversity index based on the CLPP (H&lt;sub&gt;CLPP&lt;/sub&gt;) was calculated. Edaphic properties as moisture, temperature, pH, total carbon (C) and nitrogen (N) contents were determined as possible drivers of CLPP. As expected, plant diversity was increased along the elevation gradient with the lowest H value in the mixed forest (0.6) and the highest &amp;#8211; in the alpine meadow (1.9). The H&lt;sub&gt;CLPP&lt;/sub&gt; did not differ among studied ecosystems and reached on average 2.4 for each. Microbial respiration response on amino acids was mainly contributed to dissimilarities between studied ecosystems and increased on average by 1.3 times with elevation from mixed to fir and deciduous forests. Along this elevation row, the soil N content was the most significant driver compared to other edaphic properties. Among subalpine and alpine meadows the differences between microbial responses on studied carbon substrates were not found.&lt;/p&gt;&lt;p&gt;Considering that elevation didn&amp;#8217;t contribute to distribution patterns of soil H&lt;sub&gt;CLPP&lt;/sub&gt; at the inter-ecosystems level, consequently, the hypothesis of our study was rejected. Plant diversity was not related to H&lt;sub&gt;CLPP&lt;/sub&gt; as expected. Meanwhile, the distribution patterns of soil microbial community, utilizing amino acids, along the altitudinal gradient was found.&lt;/p&gt;&lt;p&gt;The current research was financially supported by RFBR No 20-34-70121&lt;/p&gt;

scholarly journals Community Structure of Ascidian in Mike’s Point Bunaken Waters, Manado City, North Sulawesi Province

2020 ◽  
Vol 8 (1) ◽  
pp. 61
Author(s):  
Samuel L. Opa ◽  
Deiske A. Sumilat ◽  
Silvester B. Pratasik ◽  
Billy Th. Wagey ◽  
Gustaf F. Mamangkey ◽  
...  
Keyword(s):  
Distribution Pattern ◽  
Marine Invertebrates ◽  
Diversity Index ◽  
Marine Ecosystem ◽  
Distribution Patterns ◽  
Average Density ◽  
Ecological Index ◽  
North Sulawesi ◽  
Belt Transect ◽  
The Stability

Ascidians are marine invertebrates that have been classified with the subphylum Urochordata (Tunicata). These organisms are very important because they contribute a lot to the stability of the marine ecosystem. This study aims to determine the species composition, density, ecological index (diversity, uniformity, dominance), distribution patterns, and substrate occupied by Ascidian. Data were collected at Mike’s Point Bunaken waters at two depths 7 m and 14 m. The method used a direct observation along the 50 m and 2 m width belt transect. In this study, the transect was applied parallel to the coastline at each depth, where 3 replications were performed. The results show  26 species consisting of 13 species at a depth of 7 m and 22 species at a depth of 14 m were identified. The average density of each species was  0.05 ind/m2 at both depths. Diversity Index of 1.76 at 7 m depth and 2.24 at 14 m depth was determined. Uniformity Index was 0.68 at 7 m depth and 0.73 at 14 m depth. Dominant Index of 0.67 at 7 m depth and 0.88 at 14 m depth was also determined. The distribution pattern of species was dominated by uniform distribution, and the substrate most commonly occupied by Ascidianns was dead coral overgrown with algae.Keywords: Ascidian, composition and density, ecological index, distribution pattern, substrate  AbstrakAscidian adalah Avertebrata laut yang termasuk dalam subfilum Urochordata (Tunicata). Organisme ini sangat penting karena mereka banyak berkontribusi pada stabilitas ekosistem laut. Penelitian ini bertujuan untuk menentukan komposisi spesies, kepadatan, indeks ekologi (keanekaragaman, keseragaman, dominasi), pola distribusi, dan substrat yang ditempati oleh Ascidian. Data dikumpulkan di Perairan Mike's Point Bunaken pada dua kedalaman 7 m dan 14 m. Metode yang digunakan adalah pengamatan langsung sepanjang transek sabuk 50 m dan lebar 2 m. Transek dipasang sejajar dengan garis pantai dan pada setiap kedalaman.  Pengambilan data  dilakukan 3 ulangan. Hasil dari penelitian ini adalah  ditemukan  26 spesies yang terdiri dari 13 spesies pada kedalaman 7 m dan 22 spesies pada kedalaman 14 m. Kepadatan total Ascidian pada kedalaman 7 m (0,67 ind/m2) dan pada kedalaman 14 m (1.11 ind/m2). Indeks Keanekaragaman adalah 1,76 pada kedalaman 7 m dan 2,24 pada kedalaman 14 m. Indeks Keseragaman adalah 0,68 pada kedalaman 7 m dan 0,73 pada kedalaman 14 m. Indeks Dominansi 0,67 pada kedalaman 7 m dan 0,88 pada kedalaman 14 m. Pola distribusi spesies didominasi oleh pola distribusi yang seragam, dan substrat yang paling umum ditempati oleh Ascidian adalah karang mati yang ditumbuhi alga.Kata Kunci: Ascidian, komposisi dan kepadatan, indeks ekologi, pola sebaran, substrat

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