Vegetation diversification alters flying insect families in organic fields

Crop diversification affects weed communities and densities in organic spring cereal fields in northern Europe

The application of organic rice farming systems is a solution to the negative impacts of using chemicals in the application of conventional farming systems. Organic rice cultivation cannot be separated from the presence of insect pests that attack cultivated plants. Naturally, in an ecosystem that is still good, natural enemies are already present in nature without human intervention. The existence of natural enemies in a field can suppress the existing population of insect pests, so that their presence is very helpful in maintaining the balance of the existing insect pest populations. The stability of insect populations in an agricultural ecosystem is largely determined by the high diversity of insect pests and natural enemies found in a field. Thus there is a need for research on the diversity of insect pests and natural enemies as information about which insect families are found on organic rice farming land in Rowosari Village, as well as a consideration for farmers in applying appropriate control methods. This study used yellow pan trap, sweep net and vacuum cleaner insect monitoring tools. The research was conducted on 3 observation plots in the organic rice fields of Tani Jaya II Group, Rowosari Village, Sumberjambe District, Jember Regency. Observations were made 10 times from the vegetative phase to the generative phase of rice aged 7 to 77 days after planting. Observational data were then identified and then analyzed using the Shanon-Wiener Diversity Index (H), Evenness Evenness Index (E), Simpson Dominance Index (D), and Margalef Species Richness Index (R). The results showed that there were 7 families of Pest Insects found on organic rice farming in Rowosari Village, including Pyralidae, Alydidae, Grylidae, Cicadellidae, Chrysomelidae, Acrididae, and Nymphalidae. Natural Enemy Insects found were 9 families including Coccinellidea, Coenagrionidae, Gomphidae, Penttomidae, Meoidae, Miridae, Ichneumonidae, Staphylinidae, and Sciomyzidae. Neutral insects found were as many as 4 families, including Muscidae, Vespidae, Tephritidae, and Drosophilidae. The population of insect pests and natural enemies of organic rice farming land in Rowosari Village is quite balanced with a Diversity Index (H') of 2.32 and Species Richness Index (R) of 2.98, Evenness index (E') of 0.77 which is in the almost even and Dominance (D) 0.13 which means not dominating.

Macroinvertebrate communities as bioindicators of water quality in conventional and organic irrigated rice fields in Guanacaste, Costa Rica

Crop and field border effects on weed seed predation in the southeastern U.S. coastal plain

Ephemeral cropping systems are characterized by frequent disturbances of ecological processes, which may compromise the conservation of plant and arthropod diversity and the ecosystem services they may provide. Conservation biological control practices include habitat manipulations that provide non‐pest resources and selectively enhance natural enemies' effectiveness. This study, conducted in eight commercial fields of organically grown tomato, compared the effectiveness of sown flower strips with semi‐natural margins in regulating natural enemy abundance, biocontrol, and crop damage. During repeated visits, the abundance of different arthropod groups was recorded. Crop surveys included measurement of aphid abundance, parasitism, and leaf and fruit damage from sap‐sucking and lepidopteran pests. Semi‐natural habitats were associated with higher vegetation diversity, but natural enemies were more strongly associated with sown strips during flowering. Sap‐sucking pests were always recorded in higher abundance in flower strips, but crop damage in the plots adjacent to these strips was lower, suggesting that these strips may act as a trap‐crop. The inclusion of floral supplements enhanced the parasitism rate of aphids in the crop, and reduced the rate of increase of lepidopteran‐caused foliar damage with time. Early in the growing season, semi‐natural strips showed significantly lower levels of crop damage and aphid counts, suggesting that these habitats may be important during early crop colonization by natural enemies. These results indicate that the inclusion of flower strips enhances the conservation of arthropod functional diversity in ephemeral crops, and that diverse mechanisms are important for controlling different pests. However, the efficacy of habitat manipulation is likely to be greater when it is complemented with the conservation of diverse semi‐natural vegetation in the pre‐existing field margin.

Headwater regions of the streams consist an array of unique biological communities, and these ecosystems are considered the most sensitive element of river ecosystems. The significant role played by these ecosystems are well documented but the information relevant to Sri Lankan water bodies is very limited. Thus, the present study was designed to study the vegetation and benthic macro- invertebrates in relation to their habitats at upstream Sapugahadola in Walasmulla. Four sites were selected in the headwater region from upstream to downstream (S1, S2, S3 and S4) and each site was visited two consecutive months in 2018. Distribution of aquatic plants was observed along a transect (7-13 m) which placed perpendicular to the stream bank. Benthos were collected at each four sites using Surber sampler. Water quality parameters (Temperature, pH, Conductivity, Dissolved Oxygen (DO)) were measured using water quality meters while Total Suspended Solids (TSS), Biological Oxygen Demand (BOD), nitrate and phosphate contents of water were measured using the standard analytical procedures. Soil pH, soil conductivity, soil nitrate, soil phosphate and soil organic carbon were measured as soil properties. Eleven macro- invertebrate families were found in the sampling sites representing eight orders, including nine insect families. Leptoceridae, baetidae and potamonidae were the most dominant families. Benthos diversity increased towards downstream and it was noticed in the Shannon-Wiener Index (SWI). The SWI of S1, S2, S3 and S4 were 1.49, 1.72, 1.70 and 1.88 respectively. Eighteen aquatic plant species were found in the stream sites, and out of those species, Taxiphyllum sp, Bryum sp and Homaliodendron flabellatum were dominant. The most dominated phylum was bryophyte and nine species were recorded. The highest SWI for plant was found in site 3 while it was statistically similar for other sites. Benthos diversity was strongly correlated with dissolved oxygen content (r=0.85, p<0.05), soil nitrate content (r=0.95, p<0.05) while the vegetation diversity was strongly correlated with total suspended solids (r=-0.74, p <0.05) and biological oxygen demand (r=0.89, p<0.05). Although the relationship between macro-invertebrate diversity and soil quality parameters were significant, vegetation diversity was independent from soil properties. Most of the vegetation were found on rocky surfaces that were above the water level of the stream. Keywords: Vegetation, Macro- invertebrates, Diversity, Soil properties, Water quality

Syrphidae are pollinators, pest predators and decomposers in European ecosystems. Camprodon (Girona province, Spain) is a valley with rich vegetation and high habitat diversity in the eastern Pyrenees. However, hoverfly biodiversity in this valley was poorly known. To explore the high potential of this area for Syrphidae, a survey with hand-net was undertaken in July/August 2020 in the valley. The list of Syrphidae species from the valley increases to 88, whilst that of the Girona province now extends to 119 species. Chrysotoxum lessonae Giglio-Tos, 1890 is reported for the first time from the Iberian Peninsula. The specimens of Xylota tarda Meigen, 1822 and Cheilosia hypena (Becker, 1894) represent the first documented records of these species for the Iberian Peninsula and Spain, respectively; i.e. these two species were known to occur in the Iberian Peninsula and Spain but without further locality details. A total of 19 species were new to the region of Catalonia and 23 to the Girona province. Cheilosia Meigen, 1822 was the genus with the highest number of species recorded, as expected from the combination of mountains, diversity of forest vegetation, and presence of rivers/streams of the Camprodon valley. Faunistic results from this fieldwork are relevant to knowledge of Diptera from Catalonia, a region of Spain where this insect family is understudied.

The reduction of pesticides through organic farming releases some agricultural pest species from human control. We propose that this results in higher pest populations and indirectly, via plant diversity, affects avian community structure in agricultural landscapes. Therefore, we collected data on vegetation diversity (trees, bushes, herbs), from organic agrolandscapes and analyzed how vegetation diversity impacted the diversity and structure of insects and birds. The aim of this research is: i) To investigate the ecological, taxonomic, and functional structure of biodiversity in organic agricultural landscapes and its impact on ecosystem services. ii) To propose mechanisms for managing bird population in organic agro-ecosystems, considering biotic and transabiotic links. We used botanical, forestry and ecological methods to assess biodiversity. We found that plant diversity increases and species dominance decreases in ecotones approaching forest belts, insect diversity depends on the crop planted in fields, and bird diversity depends on landscape connectivity and structure. Fourteen families of insects occurred in the winter wheat field, 22 families in the buckwheat field, and 15 families in the soybean field. Among these, phytophages (40-69%) dominated, parasitic species ranged from 18 to 24%, and predators accounted for 7-26% of the total number of individuals collected. Twenty-eight bird species (6 food specialists) fed in the fields, dominated by species with broad diets. The list of species feeding in an area depended on the qualitative characteristics of the forest belt surrounding the area. We conclude that birds can serve as a practical pest control if combined with additional organic farming economic and environmental management strategies. To preserve biodiversity, it is important to take into account the structure of the forest shelterbelts, types of habitats due to the expansion of fields’ margins (ecotones), plants that resistant to damage by phytophagous insects, as well as tree species that can attract birds as a food base. Results on existing environmental risks and ways to mitigate them in organic farming can be used for systemic analyses of biodiversity structure in agro-landscapes: fields, their margins, forest shelterbelts, etc.

&lt;p&gt;Organic field crop systems are characterized by complex rotations with high spatial and temporal vegetative diversity, an enhanced use of legumes, and reduced external nutrient (nitrogen (N) and phosphorus (P)) use. At the same time, a core premise of certified organic agriculture is that this farming system provides benefits to soil health via enhanced microbial diversity. The following short review, drawing primarily upon selected studies from North America, examines the impact of farming systems, and various management strategies within these, on soil organic matter, N and P dynamics, and soil microbial and macrofaunal abundance and diversity. Organic cropping systems are shown to provide benefits with respect to reduced farm N and P surpluses, in combination with maintenance of soil organic matter and improved soil health. However, soil health benefits appear consistently achieved only for larger soil organisms partly due to the resilience of the soil microbial community. Recent research examining soil P dynamics and P uptake in relation to legume biological N&lt;sub&gt;2&lt;/sub&gt; fixation and bacterial and mycorrhizal community diversity provide evidence of the resilience of the soil microbial community with respect to functionality, if not diversity of microbial community composition. These latter results may challenge organic agriculture core premises of consistent benefits to soil health via enhanced microbial diversity, but in its place may lead to an improved understanding of how specific cropping practices and production system intensity overall, rather than farming system per se, influences both nutrient cycling and soil ecosystem functioning.&lt;/p&gt;

Tidal marsh insect communities are influenced by both salinity and aspects of vegetation texture (vegetation diversity, plant density, and architectural structure). These factors affect the abundances and intra‐ and interguild interactions of these insects and should result in broad‐scale variation in the distribution and ecological functioning of tidal marsh insect communities along these gradients. However, this assumption has not been tested within Gulf Coast marshes, and the insect communities and their ecological roles are not well known. This study identifies how family‐level insect biodiversity varies by salinity and which factors are most important in affecting the distribution of insect functional feeding groups within Louisiana's coastal marshes. Insect family diversity was found to decrease as salinity increased for several indices. Vegetation texture and the underlying salinity gradient were found to be important factors affecting the distribution of free‐living sucking, stem‐boring, parasitic, and filtering functional feeding groups.

Leaf beetles (Chrysomelidae: Coleoptera) constitute a highly diverse family of phytophagous insects with high ecological relevance, due to their host plant specificity and their close association to vegetation variables. Therefore, secondary succession and seasonal changes after loss of vegetal cover will have a significant influence on their community patterns. Accordingly, responses of leaf beetles to such environmental heterogeneity make them a suitable taxon for monitoring disturbance, which is more important for endangered habitats such as the low thorn forests (LTF) in northeastern Mexico. We conducted a study in a LTF fragment in order to assess the effects of secondary succession and seasonality on leaf beetle communities, as well as to quantify the importance of Chrysomelidae as an indicator taxon. Landsat scenes were used for delimiting a successional gradient, in which four succession categories were selected: four years, 17 years, and 31 years since loss of vegetal cover, and conserved areas. Eight plots of 100 m2 were randomly delimited in each category; plots were sampled monthly, using an entomological sweep net, from May 2016 to April 2017. In total, 384 samples were collected by the end of study, from which 6978 specimens, six subfamilies, 57 genera, and 85 species were obtained. Species richness was higher in early succession areas. Abundance declined significantly from early successional to conserved areas, but the conserved areas had the higher diversity. Furthermore, differences in abundance were significant between rainy and dry seasons in areas of four, 17, and 31 years of succession, but not in conserved areas; also, all categories had a similar abundance during the dry season. Intermediate (17 and 31 years) and conserved areas differed in the season of higher diversity. Regarding inventory completeness, it was close to or above 70 % for all comparisons, although it was very low for the 17-year category during the rainy season. Faunistic similarity was higher between intermediate categories. A total of 24 species had a significant indicator value. Effects of succession time and seasonality on leaf beetle communities are here quantified for first time in LTF forests. Influences of environmental heterogeneity and intermediate disturbance are discussed as main drivers of the results obtained. Several leaf beetle species are proposed that could be useful for monitoring succession time and secondary LTF vegetation in northeastern Mexico. However, studies must be replicated at other regions, in order to obtain a better characterization of disturbance influence on leaf beetles.

Aim This study was conducted to investigate the potential of predicting alpha diversity and turnover rates of a highly diverse herbivorous insect family (Geometridae) based on vascular plant species richness and vegetation structure.Location The study was carried out on the south‐western slopes of Mount Kilimanjaro within a wide range of habitats between 1200 and 3150 m elevation.Methods The floristic and structural composition of the vegetation was recorded at 48 plots of 400 m2. Geometrid moths were sampled manually at light sources located at the plot centres. Principal components analysis, redundancy analysis and multiple linear regression were used to explore how alpha diversity and species turnover of geometrid moths are related to vegetation structure and plant species richness.Results Alpha diversity of geometrid moths was significantly correlated with species diversity patterns in the most common vascular plant families (R2 = 0.49) and with plant structural parameters (R2 = 0.22), but not with overall floristic diversity. Species turnover of geometrid moths was strongly linked to diversity changes in a range of plant families (40% explained variance), less strongly to changes in vegetation physiognomy (25%), and only weakly to overall floristic diversity (5%). Changes in elevation were a better predictor of both alpha diversity and species turnover of geometrid moths than any principal component extracted from the vegetation data.Main conclusions Vegetation composition, diversity and structure all showed significant correlations with the diversity and species composition of geometrid moth assemblages. Nevertheless, in most cases relationships were indirect, via environmental parameters such as temperature and humidity, which influenced both vegetation and moth fauna. Possible direct links between geometrid diversity and potential food plants were much weaker. The lack of a significant correlation between overall plant species richness and geometrid diversity indicates that tropical geometrid moths may not be very selective in their food plant choice. Accordingly, a clear correlation between floral diversity and herbivore species richness must be regarded as overly simplistic, and the diversity of vascular plants cannot universally be used as a suitable biodiversity indicator for diverse insect taxa at higher trophic levels.

The study aimed to present the first record of insect families in Farwa Island. Farwa Island is the largest and most important island in Libya; located in Northern west part of Libya in the Mediterranean, its insect fauna is poorly studied. Short time intensive collection of insect samples was conducted in four areas (mouth of the valley, bay of containers, center of the Island, and Ras-Attalgha) in February, March and April 2021. Different methods were used for insect collection, sorting, preservation and later identification to the lowest taxonomic level and verification. 9 orders, 31 families, 40 genera and 58 insect species were collected in the study; the center of the Island had the highest numerical density and diversity of insect fauna due to its diverse vegetation compared to other areas. Diverse suitable habitats and absent insect control measures provided suitable environmental conditions for insects breeding, feeding and hiding from enemies. This study constitutes the first comprehensive survey of insect fauna on Farwa Island and adds significant value to the ongoing assessment of insect diversity in Libya. A long-term study has to be conducted to investigate detailed information about the abundance and diversity of insects and other arthropods on Farwa Island.