Quantifying the impact of environmental factors on the spatiotemporal structure of insect communities in a semi-arid Sabkha ecosystem

The current study highlights some knowledge on the diversity and structure of insect communities and trophic groups living in Sabkha Djendli (semi-arid area of Northeastern Algeria). The entomofauna was monthly sampled from March to November 2006 using pitfall traps at eight sites located at the vicinity of the Sabkha. Structural and diversity parameters (species richness, Shannon index, evenness) were measured for both insect orders and trophic guilds. The canonical correspondence analysis (CCA) was applied to determine how vegetation parameters (species richness and cover) influence spatial and seasonal fluctuations of insect assemblages. The catches totalled 434 insect individuals classified into 75 species, 62 genera, 31 families and 7 orders, where Coleoptera and Hymenoptera were the most abundant and constant over seasons and study stations. Spring and autumn presented the highest values of diversity parameters. Individual-based Chao-1 species richness estimator indicated 126 species for the total individuals captured in the Sabkha. Based on catch abundances, the structure of functional trophic groups was predators (37.3%), saprophages (26.7%), phytophages (20.5%), polyphages (10.8%), coprophages (4.6%); whereas in terms of numbers of species, they can be classified as phytophages (40%), predators (25.3%), polyphages (13.3%), saprophages (12%), coprophages (9.3%). The CCA demonstrated that phytophages and saprophages as well as Coleoptera and Orthoptera were positively correlated with the two parameters of vegetation, especially in spring and summer. While the abundance of coprophages was positively correlated with species richness of plants, polyphage density was positively associated with vegetation cover. The insect community showed high taxonomic and functional diversity that is closely related to diversity and vegetation cover in different site stations and seasons.

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Quantifying the impact of environmental factors on the spatiotemporal structure of insect communities in a semi-arid Sabkha ecosystem

10.7287/peerj.preprints.741v2 ◽

2015 ◽

Author(s):

Haroun Chenchouni ◽

Taha Menasria ◽

Souad Neffar ◽

Smail Chafaa ◽

Liès Bradai ◽

...

Keyword(s):

Species Richness ◽

Vegetation Cover ◽

Shannon Index ◽

Trophic Groups ◽

Insect Community ◽

Insect Communities ◽

Vegetation Parameters ◽

Two Parameters ◽

The Impact ◽

Semi Arid

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Spatiotemporal diversity, structure and trophic guilds of insect assemblages in a semi-arid Sabkha ecosystem

10.7287/peerj.preprints.741v1 ◽

2014 ◽

Author(s):

Haroun Chenchouni ◽

Taha Menasria ◽

Souad Neffar ◽

Smail Chafaa ◽

Liès Bradai ◽

...

Keyword(s):

Species Richness ◽

Vegetation Cover ◽

Shannon Index ◽

Trophic Guilds ◽

Trophic Groups ◽

Insect Community ◽

Insect Communities ◽

Vegetation Parameters ◽

Two Parameters ◽

Semi Arid

The current study highlights some knowledge on the diversity and structure of insect communities and trophic groups living in Sabkha Djendli (semi-arid area of Northeastern Algeria). The entomofauna was monthly sampled from March to November 2006 using pitfall traps at eight sites located at the vicinity of the Sabkha. Structural and diversity parameters (species richness, Shannon index, evenness) were measured for both insect orders and trophic guilds. The canonical correspondence analysis (CCA) was applied to determine how vegetation parameters (species richness and cover) influence spatial and seasonal fluctuations of insect assemblages. The catches totalled 434 insect individuals classified into 75 species, 62 genera, 31 families and 7 orders, where Coleoptera and Hymenoptera were the most abundant and constant over seasons and study stations. Spring and autumn presented the highest values of diversity parameters. Based on catch abundance, the structure of functional trophic groups was predator (37.3%), saprophagous (26.7%), phytophagous (20.5%), polyphagous (10.8%), coprophagous (4.6%); whereas in terms of numbers of species, they can be classified as phytophagous (40%), predators (25.3%), polyphagous (13.3%), saprophagous (12%), coprophagous (9.3%). The CCA demonstrated that phytophagous and saprophagous as well as Coleoptera and Orthoptera were positively correlated with the two parameters of vegetation, especially in spring and summer. While the abundance of coprophagous was positively correlated with species richness of plants, polyphagous density was positively associated with vegetation cover. The insect community showed high taxonomic and functional diversity that is closely related to diversity and vegetation cover in different site stations and seasons.

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Green Vegetation Cover Dynamics in a Heterogeneous Grassland: Spectral Unmixing of Landsat Time Series from 1999 to 2014

Remote Sensing ◽

10.3390/rs12223826 ◽

2020 ◽

Vol 12 (22) ◽

pp. 3826 ◽

Cited By ~ 1

Author(s):

Yuhong He ◽

Jian Yang ◽

Xulin Guo

Keyword(s):

Time Series ◽

Vegetation Cover ◽

Driving Forces ◽

Spectral Unmixing ◽

Landsat Images ◽

Green Vegetation ◽

Arid Grasslands ◽

Spectral Mixture ◽

The Impact ◽

Semi Arid

The ability to quantify green vegetation across space and over time is useful for studying grassland health and function and improving our understanding of the impact of land use and climate change on grasslands. Directly measuring the fraction of green vegetation cover is labor-intensive and thus only practical on relatively smaller experimental sites. Remote sensing vegetation indices, as a commonly-used method for large-area vegetation mapping, were found to produce inconsistent accuracies when mapping green vegetation in semi-arid grasslands, largely due to mixed pixels including both photosynthetic and non-photosynthetic material. The spectral mixture approach has the potential to map the fraction of green vegetation cover in a heterogeneous landscape, thanks to its ability to decompose a spectral signal from a mixed pixel into a set of fractional abundances. In this study, a time series of fractional green vegetation cover (FGVC) from 1999 to 2014 is estimated using the spectral mixture approach for a semi-arid mixed grassland, which represents a typical threatened, species-rich habitat in Central Canada. The shape of pixel clouds in each of the Landsat images is used to identify three major image endmembers (green vegetation, bare soil/litter, and water/shadow) for automated image spectral unmixing. The FGVC derived through the spectral mixture approach correlates highly with field observations (R2 = 0.86). Change in the FGVC over the study period was also mapped, and green vegetation in badlands and uplands is found to experience a slight increase, while vegetation in riparian zone shows a decrease. Only a small portion of the study area is undergoing significant changes, which is likely attributable to climate variability, bison reintroduction, and wildfire. The results of this study suggest that the automated spectral unmixing approach is promising, and the time series of medium-resolution images is capable of identifying changes in green vegetation cover in semi-arid grasslands. Further research should investigate driving forces for areas undergoing significant changes.

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Upper Cretaceous amber arthropods and their implications on changes in insect community structure

The Paleontological Society Special Publications ◽

10.1017/s2475262200007942 ◽

1992 ◽

Vol 6 ◽

pp. 234-234

Author(s):

E. M. Pike

Keyword(s):

Species Richness ◽

Upper Cretaceous ◽

Terrestrial Ecosystems ◽

Taxonomic Structure ◽

Insect Community ◽

Insect Communities ◽

Insect Fauna ◽

The Family ◽

The Usa ◽

The Baltic

Assessment of changes in terrestrial ecosystems since Cretaceous time, until recently, has had to rely on paleobotany (including paleopalynology) and vertebrate paleontology to provide data for analysis. Insects contribute a major portion of the terrestrial diversity in any ecosystem, but their fossil record and state of preservation had discouraged paleoecological study beyond the Pleistocene. With the discovery of prolific Upper Cretaceous amber deposits in Russia and Canada, and the investigation of Tertiary amber deposits from the Baltic, the Dominican Republic, Mexico and the USA, the prospect of clarifying changes in insect diversity and ecology over time becomes real. Methods are reported which allow the description of species richness and relative abundance of arthropod taxa from an Upper Cretaceous (Campanian: 75 MYA) amber deposit in Alberta, Canada. Diversity and abundance are described at the Order level for hexapods, and for the Acarina and Araneae. Taxa present, in order of abundance, are Homoptera (66 specimens/kg of amber), Diptera (28/kg), Acarina (21/kg), Hymenoptera (13/kg), Araneae (12/kg), Psocoptera (4/kg), Coleoptera (2/kg), Blattodea (1/kg), Thysanoptera (1/kg), Trichoptera (0.6/kg). Other orders present are Lepidoptera, Collembola, Dermaptera, Mantodea, and Ephemeroptera. In total, of 35 identified families, 8 are extinct. There are about 20 genera identified, of which only 1 is extant. All identified species are extinct. Estimated species richness is about 100 species of arthropods. In comparison, virtually all Families reported from Baltic amber (Oligocene) are still extant, as are the majority of genera. Morphology and feeding structures are well within the variation seen in modern insects. This suggests that throughout the Tertiary, Entomologists would feel quite at home with the insect fauna, and during the Upper Cretaceous, they would have little difficulty identifying insects at least to the family level. It is hypothesized that the taxonomic structure of modern insect communities was well established before the end of the Cretaceous, and that the structure and interrelationships of insect guilds were also very similar to those of today.

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Changes in ant species composition and community organisation along grazing gradients in semi-arid rangelands of the Northern Territory.

The Rangeland Journal ◽

10.1071/rj0000171 ◽

2000 ◽

Vol 22 (2) ◽

pp. 171 ◽

Cited By ~ 34

Author(s):

B Hoffmann

Keyword(s):

Species Richness ◽

Species Composition ◽

Group Analysis ◽

Grazing Intensity ◽

Cattle Grazing ◽

Northern Territory ◽

Rangeland Management ◽

Community Organisation ◽

The Impact ◽

Semi Arid

The impact of cattle grazing on ant diversity, species composition and community organisation was investigated in the Victoria River District of the Northern Territory, using distance from water as a surrogate of grazing intensity. Two gradients were sampled, one on red earth at Kidman Springs (5 plots), the other on black cracking clay at Mount Sanford (6 plots). Sites were sampled in April (both sites) and October (Kidman Springs only)1998. The two sites supported distinctly different ant communities, with 70 species at Kidman Springs and 36 at Mount Sanford. Species richness and total abundance did not change significantly with distance from water, although species richness was always greatest at the most distant plot. However, multivariate analysis showed that ant species composition changed markedly. Despite large changes in species composition, the abundance of only six of the 24 most common species (two at Kidman Springs and four at Mount Sanford) were significantly correlated with grazing intensity. The abundance of Bassian taxa was promoted by grazing, whereas the species richness of Torresian taxa and the abundance and species richness of Widespread taxa were suppressed. Ant functional group analysis showed community organisation was resilient, with slight changes being primarily driven by Hot Climate Specialists and dependent on the season. However, the relative richness of five functional groups correlated significantly with grazing intensity, all negatively. Ant variables suppressed by grazing were positively associated with patch cover variables and litter, and negatively correlated with annual grass and bare ground, and may serve as indicators of rangeland condition. Key words: biodiversity, cattle grazing, indicators, piosphere, rangeland management, semi-arid, tropical savannas

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The Impact of Forest Plantation Thinning on Flying Insect Community in Sukabumi Forest Management Unit

Media Konservasi ◽

10.29244/medkon.24.1.52-59 ◽

2019 ◽

Vol 24 (1) ◽

pp. 52-59

Author(s):

Ali Akbar ◽

Ahmad Budiaman ◽

Noor Farikhah Haneda

Keyword(s):

Forest Management ◽

Forest Disturbance ◽

Biological Properties ◽

Management Unit ◽

Forest Plantations ◽

Forest Plantation ◽

Insect Community ◽

Insect Communities ◽

Thinning Intensity ◽

The Impact

Insects are part of the forest ecosystem that plays an important role in the sustainability of the ecological functions of the forest plantations. The purpose of this study was to analyze the effect of thinning on insect communities and determine the types of insects which has potential to be bioindicators in order to assess the success of thinning in forest plantations. This research was conducted on forest plantation at the part of Forest Management Unit (BKPH) Cikawung and West Gede, Forest Management Resort (RPH) Ciguha, Forest Management Unit (KPH) Sukabumi Perum Perhutani Regional Division III West Java and Banten. The plot used in this research is a circular plot with a radius of 17.95 m. The traps used are malaise traps that is spread on thinning blocks at thinning intensity of 20%. The type of stand of thinning plots is Pinus merkusii in the age class 3. The obtained insects later identified to the morphospecies level. The results of the study show that thinning affect changes in environmental conditions and insect composition. In thinning blocks, there was decrease in the number of insect compositions by 11 families, 4 genera and also decrease of 3 morphospecies. Overall, thinning activities have no effect on changes over species richness index and evenness index of insect species. Diptera is a type of insect that can be used as a bioindicator, it states based on the consideration of ease in obtaining information related to taxonomy and biological properties, ease of identification, role of the ecosystem, pressure status and abundance parameters. Keywords: bioindicator, ecological assessment, forest disturbance

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Performance of Conservation Techniques for Semiarid Environments: Field Observations with Caatinga, Mulch, and Cactus Forage Palma

Water ◽

10.3390/w11040792 ◽

2019 ◽

Vol 11 (4) ◽

pp. 792 ◽

Cited By ~ 3

Author(s):

Iug Lopes ◽

Abelardo A. A. Montenegro ◽

João L. M. P. de Lima

Keyword(s):

Vegetation Cover ◽

Soil Conservation ◽

Bare Soil ◽

Natural Vegetation ◽

Soil Reclamation ◽

Soil Conditions ◽

Small Scale ◽

The Impact ◽

Semi Arid ◽

Soil Losses

Understanding small-scale hydrologic processes and the impact of soil conservation techniques are crucial in reducing runoff and sediment losses in semi-arid regions. This study was conducted in the Alto Ipanema River Basin, in Pernambuco State (Brazil). Soil and water dynamics were intensely monitored in twelve experimental plots with different coverage conditions (plot with bare soil—Bare; plot with natural vegetation—Natur; plot with mulch—Mulch; plot with Cactus Palma—Palma). By far, bare soil conditions produced higher runoff and soil losses. Mulch cover was close to natural vegetation cover, but still presented higher runoff and sediment losses. Palma, which is a very popular spineless cactus for animal feed in the Brazilian semi-arid region, presented an intermediate hydrologic impact in controlling runoff, enhancing soil moisture, and also reducing soil losses. Experiments were conducted in one hydrologic year (2016/2017) at three different sites. They were intensely monitored and had the same number of plots. This enabled us to carry out a robust performance assessment of the two soil conservation practices adopted (Mulch and Palma), compared to natural vegetation cover and bare soil conditions. Such low-cost alternatives could be easily adopted by local farms in the region, and, hence, improve soil reclamation and regional resiliency in a water-scarce environment.

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The role of grazing exclusion by fence in regulating vegetation characteristics and plant diversity in Mongolian rangelands

10.5194/egusphere-egu2020-2131 ◽

2020 ◽

Author(s):

Tong Guo

Keyword(s):

Species Richness ◽

Plant Diversity ◽

Vegetation Cover ◽

Grazing Management ◽

Grazing Exclusion ◽

Vegetation Characteristics ◽

Mongolian Rangelands ◽

The Impact ◽

Management Effects ◽

Grassland Types

Grazing largely affects vegetation dynamic of grassland communities. An intensified grazing will likely lead to grassland degradation. Therefore, to restore degraded grasslands, grazing exclusion by fence might be very helpful. However, the direction and the strength of grazing management effects on vegetation characteristics and plant diversity are currently disputable. In addition, vegetation cover and species richness are often independently examined under different grazing regimes in typical studies. Diversity-cover relationship is not adequately detected in degraded grasslands.In this study, I aim at understanding effects of grazing exclusion on vegetation characteristics, plant diversity and their relationship. For this, I performed a fencing experiment in three grassland types, namely meadow (since 2009), mountain steppe (since 2013) and dry steppe (since 2013) in Mongolia. Each of three grasslands was set by two treatments: grazing exclusion and freely grazing. Vegetation characteristics were mirrored by vegetation cover and height. Plant diversity was evaluated by indices of species richness, Shannon-Wiener diversity and Pielou evenness.The empirical results show that grazing exclusion by fence generally increases vegetation height regardless of grassland types. On the other hand, the changing direction of vegetation cover caused by grazing exclusion is not consistent in three grasslands. Fencing decreases species richness and Shannon diversity. While Pielou evenness responds slightly to changes in grazing regimes. Greater species richness benefits an increment of vegetation cover independent of grazing treatments and grassland types.This study fills the knowledge gap of grazing management effects on vegetation characteristics and plant diversity in Mongolian rangelands. The results clearly demonstrate that grazing exclusion by fence is not an efficient way to restore degraded grasslands. This will also allow to project the impact of changes in land use on ecosystem functioning.

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HISTORICAL CHANGES IN INSECT COMMUNITY STRUCTURE AS INDICATED BY HEXAPODS OF UPPER CRETACEOUS ALBERTA (GRASSY LAKE) AMBER

The Canadian Entomologist ◽

10.4039/ent126695-3 ◽

1994 ◽

Vol 126 (3) ◽

pp. 695-702 ◽

Cited By ~ 16

Author(s):

Edward M. Pike

Keyword(s):

Species Richness ◽

Community Structure ◽

Dominican Republic ◽

Relative Abundance ◽

Upper Cretaceous ◽

Taxonomic Structure ◽

Insect Community ◽

Insect Communities ◽

Insect Assemblage ◽

Insect Guilds

AbstractSpecies richness and relative abundance of arthropod taxa from an Upper Cretaceous (Campanian: 75 Mya) amber deposit in Alberta are described. About 130 hexapod species have been recognized to date from this deposit, making it the most diverse Cretaceous insect assemblage so far known. Taxa present, in order of abundance, are Hemiptera (66 specimens per kg), Diptera (28), Acari (21), Hymenoptera (13), Aranaea (12), Psocoptera (4), Coleoptera (2), Blattodea (1), Thysanoptera (1), and Trichoptera (0.6). Representatives of Lepidoptera, Collembola, Dermaptera, Mantodea, Phasmatodea, and Ephemeropteraare are also present. In the total of 65 identified families, 15 are extinct. Only one of about 77 genera identified in this deposit is extant. All recognized species are extinct. In comparison, virtually all families reported from Baltic and Dominican Republic ambers are extant, as are the majority of the genera. Morphology and feeding structures are well within the variation seen in modern insects. It is hypothesized that the taxonomic structure of modern insect communities was well established before the end of the Cretaceous and that the structure and interrelationships of insect guilds were also very similar to those of today.

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Urban Fire Severity and Vegetation Dynamics in Southern California

Remote Sensing ◽

10.3390/rs13010019 ◽

2020 ◽

Vol 13 (1) ◽

pp. 19

Author(s):

Lauren E. H. Mathews ◽

Alicia M. Kinoshita

Keyword(s):

Vegetation Cover ◽

Vegetation Index ◽

Normalized Difference Vegetation Index ◽

Current Knowledge ◽

Fire Severity ◽

Satellite Image ◽

Burn Severity ◽

Native Vegetation ◽

Riparian Areas ◽

The Impact

A combination of satellite image indices and in-field observations was used to investigate the impact of fuel conditions, fire behavior, and vegetation regrowth patterns, altered by invasive riparian vegetation. Satellite image metrics, differenced normalized burn severity (dNBR) and differenced normalized difference vegetation index (dNDVI), were approximated for non-native, riparian, or upland vegetation for traditional timeframes (0-, 1-, and 3-years) after eleven urban fires across a spectrum of invasive vegetation cover. Larger burn severity and loss of green canopy (NDVI) was detected for riparian areas compared to the uplands. The presence of invasive vegetation affected the distribution of burn severity and canopy loss detected within each fire. Fires with native vegetation cover had a higher severity and resulted in larger immediate loss of canopy than fires with substantial amounts of non-native vegetation. The lower burn severity observed 1–3 years after the fires with non-native vegetation suggests a rapid regrowth of non-native grasses, resulting in a smaller measured canopy loss relative to native vegetation immediately after fire. This observed fire pattern favors the life cycle and perpetuation of many opportunistic grasses within urban riparian areas. This research builds upon our current knowledge of wildfire recovery processes and highlights the unique challenges of remotely assessing vegetation biophysical status within urban Mediterranean riverine systems.

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