Phytoplankton community structure changes in Thi Nai lagoon (South - Central Vietnam) from 2004 to 2020

Phytoplankton species composition, abundance, biodiversity indices and their influence by environmental conditions were examined in Thi Nai lagoon using data from four surveys in 2004, 2008, 2009 and 2020. A total of 367 taxa of phytoplankton belonging to ten groups was recorded, of which diatoms were dominant with over 60% of the total species. In Thi Nai lagoon, the number of phytoplankton species decreased from the upper lagoon (283 taxa) to the lagoon mouth area (224) and was lowest in river stations (139). The species number was much lower in the rainy season (<95 species) and increased from 2004 to 2020. Among the biodiversity indices, Shannon, ∆, s∆+, Λ+ and sФ+ were lower in the rainy season, whereas ∆*, ∆+ and Ф+ had lower values in the dry season. For long-term analysis, the differences were especially significant at upper and lower lagoon for ∆, ∆*, ∆+, s∆+ and sФ+. In the dry season, the mean density of phytoplankton was lower at the river stations and upper lagoon, but higher at the lower lagoon and the lagoon mouth area. There was a clear difference of species assemblages between the two seasons with average dissimilarities in each area ranging from 94.16% to 95.57%. During 2004–2020, the difference in ratios between the main phytoplankton groups were small over years but there was a complete change in dominance of particular species, assemblage dissimilarities were from 73.4 to 77.9, greatest between 2009 and 2020. The lagoon was low in biodiversity for the whole investigated time indicated by taxonomic index ∆+. Among biodiversity indices, species richness (S), taxonomic indices (∆*, s∆+), and phylogenetic indices (Ф+, sФ+) were more sensitive to the changes of the aquatic environment than other traditional indices.

Biodiversity Indices and Medically Importance of Ticks in North Khorasan Province, Northeast of Iran

Background: Ticks are considered as the main vectors for the transmission of various pathogens such as relapsing fever and CCHF to humans. This study was investigated the biodiversity indices and medically importance of ticks in North Khorasan Province, Northeast of Iran during 2015–2019. Methods: Specimens were captured from infested ruminants including cows, sheep, and goats. Additionally, tick col­lections also were performed on non-domesticated creatures such as turtles, rodents, and hedgehogs. Specimens were identified using valid identification keys. Species diversity, species richness and evenness indices have been calculated to estimate species biodiversity of ticks. Results: A total of 1478 adult ticks were collected. The specimens were from two families: Ixodidae (90.05%) and Ar­gasidae (9.95%), 6 genera and 17 species including: Rhipicephalus sanguineus (55.9%), Rhipicephalus bursa (13.4%), Hyalomma marginatum (9.5%), Hyalomma anatolicum (9.5%), Hyalomma asiaticum (0.2%), Hyalomma aegyptium (0.5%), Hyalomma scupense (1.3%), Hyalomma sp (1.2%), Haemaphysalis sulcata (0.7%), Haemaphysalis erinacea (0.1%), Haemaphysalis inermis (0.1%), Haemaphysalis punctata (0.2%), Haemaphysalis concinna (0.1% Boophilus annulatus (1.2), and Dermacentor marginatus (6.1%) among hard ticks as well as Argas persicus (91.8%) and Argas reflexus (8.2%) amongst soft ticks. Rhipicephalus sanguineus, Rh. Bursa, Hy. marginatum and Hy. anatolicum were known as the most frequent species of hard ticks. Tick’s species richness, Shannon diversity index and Simpson index in this area were S= 17, H’= 1.69, D= 0.294 respectively. Conclusion: Based on tick distribution veterinary authority, public health organizations and other officials should act for implementation of disease prevention.

Detection of biodiversity local centers and gradients of change of Dolichopodidae (Diptera) in East Asia

The dolichopodid fauna of continental Chinese and Russian regions belonging to the East Palaearctic have been selected for a comparative diversity investigation. We gathered information about 654 species of long-legged flies in the studied areas. Regarding the total species number, Primorsky Kray and Republic of Sakha in Russia, Henan and Shaanxi in China, as well as Mongolia are the top five regions, each with more than 100 species known. Cluster analysis of the dolichopodid genera composition allows us to divide all studied territories into two groups: Group A is mixed, since it includes both the Russian regions and the Chinese provinces; Group B includes only Russian regions. Generally, the mathematical analysis of the dolichopodid species supports the uniqueness of Primorsky Kray as the biodiversity center in East Asian Palaearctic. A decrease in the number of known species and biodiversity indices is observed northward, southward and westward of Primorsky Kray. One more possible center is located closely to the Oriental provinces of China (Henan and Shaanxi provinces).

Potential and Limitations of Grasslands α-Diversity Prediction Using Fine-Scale Hyperspectral Imagery

Plant biodiversity is an important feature of grassland ecosystems, as it is related to the provision of many ecosystem services crucial for the human economy and well-being. Given the importance of grasslands, research has been carried out in recent years on the potential to monitor them with novel remote sensing techniques. In this study, the optical diversity (also called spectral diversity) approach was adopted to check the potential of using high-resolution hyperspectral images to estimate α-diversity in grassland ecosystems. In 2018 and 2019, grassland species composition was surveyed and canopy hyperspectral data were acquired at two grassland sites: Monte Bondone (IT-MBo; species-rich semi-natural grasslands) and an experimental farm of the University of Padova, Legnaro, Padua, Italy (IT-PD; artificially established grassland plots with a species-poor mixture). The relationship between biodiversity (species richness, Shannon’s, species evenness, and Simpson’s indices) and optical diversity metrics (coefficient of variation-CV and standard deviation-SD) was not consistent across the investigated grassland plant communities. Species richness could be estimated by optical diversity metrics with an R = 0.87 at the IT-PD species-poor site. In the more complex and species-rich grasslands at IT-MBo, the estimation of biodiversity indices was more difficult and the optical diversity metrics failed to estimate biodiversity as accurately as in IT-PD probably due to the higher number of species and the strong canopy spatial heterogeneity. Therefore, the results of the study confirmed the ability of spectral proxies to detect grassland α-diversity in man-made grassland ecosystems but highlighted the limitations of the spectral diversity approach to estimate biodiversity when natural grasslands are observed. Nevertheless, at IT-MBo, the optical diversity metric SD calculated from post-processed hyperspectral images and transformed spectra showed, in the red part of the spectrum, a significant correlation (up to R = 0.56, p = 0.004) with biodiversity indices. Spatial resampling highlighted that for the IT-PD sward the optimal optical pixel size was 1 cm, while for the IT-MBo natural grassland it was 1 mm. The random pixel extraction did not improve the performance of the optical diversity metrics at both study sites. Further research is needed to fully understand the links between α-diversity and spectral and biochemical heterogeneity in complex heterogeneous ecosystems, and to assess whether the optical diversity approach can be adopted at the spatial scale to detect β-diversity. Such insights will provide more robust information on the mechanisms linking grassland diversity and optical heterogeneity.

Species composition and biodiversity indexes of weeds in paddy rice on two sides of dike system during three crops in an Giang Province, Vietnam

Aim: This study was conducted to provide data on weed species composition and biodiversity indexes at different rice crops inside and outside of the dike system in An Giang province, Vietnam. Methodology: Weeds were collected from paddy rice of inner and outer side of dike system from six districts of An Giang province, Vietnam. From each sampling sites, two quadrats with 100 m2 (10 m × 10 m) per quadrat were selected to collect weed after 75-80 days of rice planting. Weeds were collected and identified for their scientific name, and the number of each species was defined, followed by calculation of the occurrence frequency and density of samples. Biodiversity indices viz. Shannon-Weaver (H’), Simpson (1- λ), Margalef (d), and similarity index were also studied among three crops and two sides of dike system. Results: The weed composition in the paddy rice in An Giang was diversity with 137 species. Among them, the most species belonged to families Poaceae, Cyperaceae, and Compositae. The species composition of Crop 3 was the highest one. Species occurrence frequency and weed density of groups C, D, E reached the highest value in Crop 1, followed by Crop 2 and 3. The biodiversity indices of weed species composition in the studied sites were high, reaching the highest value in Crop 3. Interpretation: The results of this study enhance the knowledge of weed species composition and biodiversity indexes to effectively manage and control weeds in rice cultivation.

Assessment of Diversity Indices and DNA Barcoding of Parasitic Fauna Associated with Groundnut Leafminer (GLM), Aproaerema modicella Deventer (Lepidoptera: Gelechiidae)

Background: Parasitoid wasps have received a great share of heed in the biological control of pests. However, they are often difficult to identify because of their small body size and profound diversity. In this view, biodiversity indices of parasitic fauna was reckoned and proper identification of those biocontrol agents were done through morphological and molecular technique such as DNA barcoding.Methods: Biodiversity indices of parasitoid of Groundnut Leafminer (GLM), Aproaerema modicella Deventer were reckoned for three agroclimatic zones viz., Irrigated Eastern zone (IE), Rainfed zone (R) and Irrigated Western zone (IW) of Tamil Nadu. Biodiversity indices viz., Relative density, Simpson’s Index, Shannon-Wiener Index, Pielou’s Evenness Index, Margalef Index and Beta diversity were assessed for the parasitic fauna associated with GLM. Apart from this, morphological characterization of prominent parasitoids were done with the help of available literatures and taxonomic experts. The molecular characterization of parasitoids were done using mitochondrial Cytochrome Oxidase I (mtCOI).Result: The relative density of parasitoid families and species indicated the dominance of braconidae and Chelonus blackburni Cameron. Among the agroclimatic zones, rainfed zone had higher species diversity, richness and evenness. In addition, the morphological and molecular confirmation revealed that the parasitoids associated with A. modicella as Temelucha spp., Stenomesius japonicus, Bracon hebetor, Sympiesis dolichogaster, Chelonus blackburni and Avga choaspes. The amplified sequences were submitted to NCBI database and accession numbers were obtained.

Seasonal Variation of Water Quality Parameters and Their Impact on Fish Biodiversity Indices of Hasadanga Beel: A Case Study

Fish diversity indices and their correlation with seasonal fluctuation of physicochemical parameters of Hasadanga beel was aimed to be studied. A three-year study on the relationship between the seasonal fluctuation of water quality parameters and fish biodiversity indices was conducted in Hasadanga Beel, a floodplain lake of Nadia district, West Bengal to measure the ecological health of the lake. Samples of water and fish species were collected at pre-monsoon, monsoon and post-monsoon period from 2015-2017 to estimate physicochemical parameters of water and fish biodiversity indices i.e. Shannon-Weaver species diversity index, Margalef’s Species richness index, Pielou’s Species evenness index and Simpson’s index of dominance. Total of 34 different fish species belonging to 8 Orders were found during the study period which varies seasonally. Water temperature (20.0-31.4 °C), pH (7.70-8.75), dissolved oxygen (3.9-5.0 mg/l), Free CO2 (0.0-15.0 mg/l), total alkalinity (156-193 mg/l), hardness (113-145 mg/l), and BOD (1.03-1.94 mg/l) values varied significantly (p<0.05) between three seasons. Shannon-Weaver species diversity index (Hꞌ) is ranged between 1.2911-1.3502, Margalef’s species richness index (D) is measured between 12.72-14.15, Pielou’s species evenness index (Jꞌ) is recorded between 0.8829-0.9140 and Simpson’s index of dominance (ID) is ranged between 0.05346-0.07139. Hꞌ has positive correlation with pH, alkalinity and hardness whereas negative correlation with temperature, free CO2, DO and BOD. D has positive correlation with pH, free CO2, DO and hardness whereas negative correlation with temperature, alkalinity and BOD. Jꞌ has positive correlation with temperature, pH, alkalinity and hardness and whereas negative correlation with free CO2, DO and BOD. ID has positive correlation with temperature, free CO2, DO and BOD whereas negative correlation with pH, alkalinity and hardness. The obtained result suggests that various water quality parameters specially temperature, dissolved oxygen and pH are the key factors to regulate the fish biodiversity indices and should be taken into consideration for making policies for sustainable use of floodplain lakes.