Shannon-Wiener Index Research Articles

Nature-based bank protection measures improve benthic macroinvertebrates in a stream draining an agriculturally dominated watershed

Increased bank erosion is one of the most significant threats to agricultural stream ecosystems. However, it is challenging to ascertain whether bank restoration measures positively affect in-stream habitats and aquatic communities. This study evaluated three nature-based bank protection measures' short-term (2-year) effects on aquatic physical habitat quality and benthic macroinvertebrate communities in a headwater stream in agricultural areas. The results demonstrate that nature-based bank protection measures can significantly improve the quality of aquatic physical habitat in streams. The TPRW (timber piles + riprap + willow cuttings) and WTRW (waste tires + riprap + willow cuttings) measures exhibited the most pronounced improvement in the quality of aquatic physical habitat in streams. The diversity of benthic macroinvertebrates was the highest in the TPRW reach, and the seasons significantly affected the density of benthic macroinvertebrates. The Shannon-Wiener diversity index and Margalef's richness index were the most consistent with the changing trend of physical habitat quality and are effective indicators of the ecological effects of stream restoration measures in our study area. In this study area, TPRW is the preferred measure for streambank restoration of agricultural streams, and WTRW is the alternative measure. However, the ecological effects of WTRW need to be monitored over a more extended period to identify whether there is potential ecotoxicity in the process of weathering and decomposition.

Attributing spatially stratified heterogeneity in biodiversity of urban–rural interlaced zones based on the OPGD model

Urban–rural interlaced zones are characterized by the interpenetration of urban and rural elements, drastic changes in construction, relatively weak planning and management, and anthropogenic activities that constantly impact the ecological background. However, the ecological barriers and hinterland spaces of the city center provide important ecological functions. In this study, we selected forest birds as indicator species of the urban ecological environment and explored the spatial stratification and heterogeneity effects of environmental substrates and anthropogenic activities on bird diversity (species richness, abundance, Shannon–Wiener index, and Simpson index) in urban–rural interlaced zones using the optimal parameter geographic detector model to characterize the changes in ecological functions in these zones. The results of this study are as follows:(1) The bird diversity index in Minhang District, Shanghai, showed an obvious urban-rural gradient divergence with the transition of urban zone- rural-urban interface - rural zone.An agglomerative spatial differentiation pattern was observed more in the southeast but less in the northwest, with a high degree of spatial distribution concentrations and evident imbalance characteristics.(2) The spatially stratified heterogeneity in bird diversity in urban–rural interlaced zones was because of the combined action of multiple driving factors under the three dimensions of habitat environment, degree of urbanization, and anthropogenic interference. Most of the interactions between any two factors showed non-linear or bifactorial enhancement effects. Furthermore, the one-factor explanatory power of urbanization and anthropogenic interference factors on bird diversity was significantly higher than that of the habitat environment factor.(3) Population heat distribution (PD), distance to the center of Shanghai (DC), and nighttime lighting index(NTL) were the main drivers of spatially stratified heterogeneity in bird diversity and the key indicators of urban–rural gradient changes. The interaction between PD and DC had the strongest explanatory power for the spatial differentiation of bird diversity.

Foraging ecology of southern sea otters at the northern range extent informs regional population dynamics

Sea otters Enhydra lutris are vital keystone predators throughout the North Pacific that were nearly extirpated during the maritime fur trade. Recovery of southern sea otters E. l. nereis has proceeded slowly, with much of their historical range remaining unoccupied, resulting in reduced ecosystem functioning. Numerous studies have used foraging metrics to assess the population status of southern sea otters throughout their current range, but little is known about the northern range extent, where a stall in expansion has limited recovery. Thus, we collected census and foraging data of sea otters at Año Nuevo State Park, California, from 2019 to 2021 to determine sea otter abundance, diet composition, diet diversity, and average energy intake rate at the northern range edge. We then assessed regional population status by comparing values from Año Nuevo with previously collected data from other locations in California, including high-density, range center sites and low-density, range periphery sites. We found that sea otter density at Año Nuevo was greater than surrounding areas at the northern range periphery, and the average (±95% CI) energy intake (9.51 ± 0.91 kcal min-1) more closely resembled values observed at high-density sites. Further, dietary diversity (using the Shannon-Wiener index, H) was intermediate between previously studied high- and low-density populations (H = 1.81), with crabs making up the largest proportion of the diet (~56%). Overall, this study highlights possible effects of occupation time and range stagnation, identifies unique aspects of the prey resource base at Año Nuevo, and provides insight into the ongoing lack of northern range expansion.

DIVERSITY OF BATS IN HALABAN MONITORING POST AREA, SEI BETUNG, GUNUNG LEUSER NATIONAL PARK

Halaban Monitoring Post, Sei Betung Resort, Gunung Leuser National Park is a rehabilitated forest restoration location since 2017 after previously being diversified from oil palm land. The location has currently become a habitat for various types of animals, including bats. The identification of bat species at the Halaban Monitoring Post is conducted to assess the presence of fauna, with important ecological roles in pollination. Identification was conducted using mist nets installed at five observation points. Our observations showed that 87 individuals of Microchiroptera family bats were found, belonging to 4 species: Cynopterus brachyotis (38 individuals), Cynopterus minutus (15 individuals), Glischropus tylopus (1 individual), Hipposideros cervinus (33 individuals). Further analysis showed Shannon-Wiener diversity index ranges from 0.0 to 0.94 and Margalef species richness index ranges from 0.0 to 0.69. Bat abundance tends to be evenly distributed with an evenness index of 0.0 to 1.35. There is a dominant species at one of the locations with a dominance index value of 0.85.

Unveiling the effects of environmental factors and Yellow River inputs on the ichthyoplankton community structure in typical bays

To unravel the effects of environmental factors on fishery resources in the bay, we conducted six biological and environmental surveys in the Laizhou Bay between 2013 and 2020. The findings of our study illuminated several key aspects: (1) The annual discharge of water and sediment from the Yellow River to Laizhou Bay exhibited notable variations, while concurrently, environmental factors including temperature, salinity, and suspended particle matter underwent fluctuations, yet remained within a relatively stable range overall. (2) A total of 8318 eggs and larvae belonging to 10 orders, 16 families, and 19 genera were collected. Significant interannual fluctuations had been documented in the species composition, abundance, and biodiversity of ichthyoplankton. Notably, both Shannon-Wiener diversity index and Pielou evenness index were significantly negatively correlated with suspended particle matter concentration. (3) The water and sediment discharge significantly positively correlated with the number of cold-temperature species. However, the sediment input negatively correlated with the number of continental shelf benthopelagic fish. (4) Redundancy and correlation analyses confirmed the strong link between spatial and temporal distribution of fish communities and environmental factors, with salinity and dissolved oxygen key for ichthyoplankton abundance. Our research offers a scientific foundation for targeted fishery protection and management, which is crucial for preserving the ecological functions of spawning grounds in the bay.

The effect of the tidal cycle on the phytoplankton community assemblage in a mangrove-dominated tropical tidal creek.

A comparative assessment of phytoplankton dynamics during low tide (LT) and high tide (HT) was conducted from February 2022 to January 2023 in a tropical mesotidal creek, Manori, Mumbai, India. In total, 124 phytoplankton species were recorded. The HT resulted in greater species richness (124 species) and diversity indices (Shannon-Wiener's index) than the LT (102 species). The Pielou's evenness (J') and Simpson's dominance index (1-D) did not show significant fluctuations with the tides due to the marine phytoplankton species moving rhythmically in and out of the creek with the tides. Overall, the seasonal abundance was maximum during pre-monsoon at HT (5.79 × 103 u/L) and lowest in monsoon at LT (0.45 × 103 u/L), whereas spatial abundance was maximum at S1 (HT- 4.04 × 103 u/L) at HT and lowest at S3 (LT- 0.75 × 103 u/L) at LT. The diatoms dominated in their abundance (1.83 × 103 u/L and 3.82 × 103 u/L in HT) and diversity (77 in LT and 92 in HT). The species such as Coscinodiscus centralis, Coscinodiscus granii, Coscinodiscus radiatus, Triops furca, Melosira varians, Nitzchsia palea, Chaetoceros affinis, Skeletonema marinoi, Stephanocyclus meneghinianus, Planktoniella sol and Skeletonema costatumwere the dominant native residents in the creek. SIMPER analysis revealed that the maximum similarity was during the monsoon (47.65%), and the minimum was during the pre-monsoon (38.10%) at LT. However, in HT, the maximum similarity of phytoplankton shifted to post-monsoon (63.85%) and the minimum during the pre-monsoon (46.71%). The mean value of richness (d') and Shannon's diversity (H') showed a moderate phytoplankton diversity in the system. The environmental parameters (water temperature > pH > nitrate > salinity > DO > Alk > silicate) have a greater influence on the distribution of the phytoplankton community with tides as revealed by the Canonical correspondence analysis. Therefore, it has been found that tides play a significant role in the distribution and abundance of the phytoplankton community in a mesotidal creek environment.

Initial Alterations of Fish Community Structure and Diversity Following Fishing Cessation in Qilu Lake, China.

The Qilu Lake is an eutrophic shallow lake located in Yunnan Province, China. An ecological fishery project was initiated in the lake from 2011 to 2021 to introduce filter-feeding fish species that feed on algae, with the aim of improving water quality. In January 2022, when the ecological fishery project expired, all fisheries-related activities (including fish stocking and fishing activities) ceased in the lake. To comprehensively evaluate the initial alterations in fish community structure and diversity resulting from the fishing cessation in the Qilu Lake, the present study conducted field surveys within the one year before the fishing cessation (referred to as BFC) and the one year after the fishing cessation (referred to as AFC). A total of twenty-one fish species were collected, including four native species. Four species were recorded in the lake for the first time, including Pelteobagrus fulvidraco, Pelteobagrus vachelli, Paramisgurnus dabryanus, and Hyporhamphus intermedius. The number of fish species decreased from 21 to 13 following the fishing cessation. The fishes collected in both BFC and AFC are mainly omnivorous-feeding and of bottom-dwelling habits. The mean size of the fishes in the AFC sample shows a significant decrease compared to those in BFC. After the fishing cessation, the Shannon-Wiener diversity index and Margalef richness index of the fish slightly declined. The fish community structure of the Qilu Lake exhibits a high degree of similarity to adjacent lakes in central Yunnan. Our study demonstrates a significant shift in the fish community of the Qilu Lake following the fishing cessation, one which may adversely impact the stability of the lake ecosystem. To enhance fish species diversity in the Qilu Lake, it is recommended that policies be implemented to promote the ecological fishery project and improve habitat restoration for native fish species, while also regulating fish community structure.

Assessment of Macro-Invertebrates of Gubi and Waya Dams in Bauchi State, Nigeria

This study assessed the diversity, abundance, and composition of macro-invertebrates in the Gubi and Waya Dams in Bauchi State. Macro-invertebrates were collected fortnightly from different locations in the upper and lower parts of the dams using a D-frame net with a mesh size of 250 µm. Samples were preserved in 10% formaldehyde and identified. In Gubi Dam, 62 individual macro-invertebrates belonging to 7 orders and 9 families were identified, while Waya Dam had 108 individuals from 8 orders and 10 families. Both dams had Coleoptera with three families, followed by Odonata with two families, and other orders with one family each. In Gubi Dam, the most abundant macro-invertebrates were Psephenus spp. (24.1%), Paragomphus genei (17.74%), and Phaon camerunensis (16.13%). In Waya Dam, Paragomphus genei (29.63%) and Phaon camerunensis (25.93%) were the most abundant. Gubi Dam had a Shannon-Wiener index of 2.00, a Margalef’s index of 1.99, Pielou’s evenness index of 0.91, and a Simpson’s index of 0.86. Waya Dam had a Shannon-Wiener index of 1.88, a Margalef’s index of 1.92, an evenness index of 0.82, and a Simpson’s index of 0.81. The study concluded that both dams provide stable and moderate aquatic environments for the growth and survival of macro-invertebrates as well as other aquatic organisms. Continuous monitoring of the water bodies, especially Waya Dam, using water indices and pollution indicator macro-invertebrates to obtain vital information on ecological status is recommended.

Grazing exclusion enriches arbuscular mycorrhizal fungal communities and improves soil organic carbon sequestration in the alpine steppe of northern Tibet

Fencing for grazing exclusion is regarded as a traditional and effective method for the natural restoration of degraded alpine steppe, and it effectively promotes plant growth and enhances soil carbon stocks. Arbuscular mycorrhizal fungi (AMF) are essential microorganisms in grassland that play a major role in plant-derived C translocation into the soil. However, the effects of fencing on AMF communities and their contributions to soil carbon sequestration are still unclear. In this study, alpine steppe areas with three different fencing durations (free grazing, medium-term fencing for 5-6 years and long-term fencing for more than 10 years) in the northern Tibetan Plateau were selected to explore the effects of grazing exclusion on AMF communities and their roles in soil carbon sequestration. The results showed that medium- and long-term fencing significantly increased both plant aboveground biomass and soil organic carbon (SOC) content. The AMF community composition varied significantly during different fencing durations, with a dramatic increase in the relative abundance of Glomus but a significant reduction in the relative abundance of Diversispora with longer fencing time. Medium-term fencing significantly increased AMF richness and the Shannon-Wiener index. Meanwhile, fencing significantly increased hyphal length density (HLD), glomalin-related soil protein (GRSP) and the proportion of macroaggregates (250-2,000 μm), all of which contribute positively to SOC. Structural equation modeling revealed that fencing time positively influenced HLD and the AMF community composition, subsequently affecting T-GRSP, which was tightly correlated with SOC. Our findings suggest the potentially important contribution of AMF to SOC sequestration, so more attention should be paid to AMF during alpine steppe fencing, particularly for enhancing the efficiency of degraded grassland restoration efforts.

Anti-seasonal flooding drives substantial alterations in riparian plant diversity and niche characteristics in a unique hydro-fluctuation zone.

Human-induced disturbances such as dam construction and regulation have led to widespread alterations in hydrological processes and thus substantially influence plant characteristics in the hydro-fluctuation zones (HFZs). To reveal utilization of limited resources and mechanisms of inter-specific competition and species co-existence of plant communities based on niche breadth and overlap under the different HFZs of the Three Gorges Reservoir (TGR) in China, we conducted a field investigation with 368 quadrats on the effects of hydrological alterations on plant diversity and niche characteristics. The results showed anti-seasonal flooding precipitated the gradual disappearance of the original diverse niches, resulting in the reduction of plant species richness and functional diversity and more obvious competition among plant species with similar resource requirements. Annuals, perennials and shrubs accounted for 71.23%, 27.39% and 1.37%, respectively, suggesting that annuals and flood-tolerant riparian herbs were favored under such novel flooding conditions. A consistent increase in species number, Shannon-Wiener diversity index and Simpson dominance index with altitude was inconsistent with hump-shaped diversity-disturbance relationship of the intermediate disturbance hypothesis, while the opposite trend was observed for the Pielou evenness index. This species distribution pattern might be caused by several synergetic attributes (e.g., the submergence depth, plant tolerant capacity to flooding, life form, dispersal mode and inter-specific competition). Vegetation types shifted from xerophytes to mesophytes and eventually to hygrophytes with the increasing flooding time in the HFZs. Hydrological alterations proved to be the paramount driver of vegetation distribution in the different HFZs. The niche analysis provided the first insights on the mechanisms of resource utilization and inter-specific competition, of which annuals could germinate quickly after soil drainage to achieve the greatest competitive advantages and occupy a larger niche space than other plants. Vegetation was still in the early stage of primary succession in the novel riparian forests. Therefore, vegetation restoration strategies should be biased towards herbaceous plants, due to annuals with better environmental adaptability, supplemented by shrubs and small trees. To establish a complete reference system for vegetation restoration, natural vegetation monitory plots in the different succession stages should be established in the different HFZs of the TGR, and their environmental conditions, community structures and inter-specific relationships further analyzed.

Exploration of the Dayak Onion (Eleutherine palmifolia (L.) Merr) in the Borderlands of North Kalimantan, Indonesia

The Dayak onion (Eleutherine palmifolia (L.) Merr) is a plant endemic to Kalimantan, Indonesia, known for its medicinal properties. This study explores the distribution and morphological diversity of Dayak onions in the border areas of North Kalimantan, encompassing Tana Tidung, Bulungan, Malinau Regencies, and Tarakan City. Fifteen unique accessions were collected, and their morphological traits were characterized both qualitatively and quantitatively. The distribution analysis revealed an even spread of Dayak onions across the studied regions. The diversity analysis, using the Shannon-Wiener index, indicated variations in certain quantitative traits like plant height and root length, while qualitative traits like leaf and bulb characteristics remained largely uniform. Principal Component Analysis (PCA) identified key morphological characters contributing to the observed diversity, and cluster analysis revealed kinship relationships among the accessions, with some groups showing high similarity coefficients. This research provides valuable insights into the distribution, diversity, and genetic relationships of Dayak onions in North Kalimantan, contributing to potential agricultural and conservation applications.

Community Structure of Sea Cucumbers (Holothuroidea) in The Intertidal Zone of Koepisino Beach, North Buton

Sea cucumbers are marine invertebrates belonging to the class Holothuroidea, living in various aquatic environments ranging from shallow coastal waters to deep seas. Sea cucumbers have an important ecological function in coral reef ecosystems. The aim of the research is to determine the community structure of sea cucumbers (Holothuroidea) in the intertidal zone of Koepisino Beach, North Buton. The research method used was quantitative descriptive research conducted in the intertidal zone of North Koepisino Buton Beach. Data collection was carried out by exploring each station measuring 50 × 100 meters for 3 stations. Data analysis was descriptive quantitative, In the intertidal zone of Koepisino Beach, North Buton, 12 species of sea cucumbers belonging to two orders, Aspidochirotida (genera Holothuria, Bohadschia, Telonata, and Stichopus) and Apodida (genera Synapta and Opheodesoma), were discovered. The community structure components analyzed in this study were abundance, diversity index, uniformity index, and dominance index.The highest abundance of sea cucumber species was at station I (sand substrate) at 0.009 (ind/m2). The lowest species abundance was at station III (coral rubble substrate) at 0.005 (ind/m2). H. scabra is the species with the highest abundance, namely 0.0026 ind/m2, while Bohadschia similis, Bohadschia vitiensis, Opheodesoma spectabilis, Telonata ananas are the species with the lowest abundance, namely 0 ind/m2. The Shannon-Wiener sea cucumber diversity index (H') is in the medium category 2.144. The sea cucumber uniformity index at the research location is high (E > 0.6) and there is no dominant species.

Effects of isolation on invertebrate biodiversity among the bladderwrack Fucus vesiculosus

Geographic isolation is a factor that is known to affect species composition and diversity in marine systems. In this study, we tested the effects of geographic isolation on invertebrate fauna living among the belt-forming foundation species Fucus vesiculosus in the northern Baltic Sea. Sampling was carried out on reefs with varying levels of isolation (0.5, 1 and 2 km) in July 2021 in the Åland islands (between 59.96°N 20.24°E and 59.75°N 20.84°E). The total number of taxa, abundance, Shannon-Wiener index, Pielou’s evenness and biomass were calculated and the effects of isolation were tested using generalised linear models. Multivariate methods were used to analyse differences in the invertebrate community composition. Although the number of taxa and Shannon´s diversity index did not vary along the isolation gradient, the total abundance of fauna decreased with increasing isolation. In addition, some taxa-specific patterns were observed, e.g. the abundance of insect larvae decreased with isolation while isopods were more numerous in the most isolated locations. As diversity and the number of taxa were similar regardless of isolation, shallow Fucus vesiculosus belts likely act as important biodiversity refuges and potential stepping-stones for invertebrates in remote outer archipelago areas. In a changing climate, these kinds of refuges aiding species dispersal are likely to be even more important, and should be considered in conservation planning.

Community Structure of Mollusca (Gastropoda and Bivalvia) at Toronipa Beach

Toronipa Beach is known to have high biodiversity, especially in the Mollusca community such as Gastropoda and Bivalvia. However, research on the distribution and abundance of Mollusca species in this area, especially related to environmental changes, is still limited. To fill this gap, an analysis study was conducted on the structure of the Toronipa Beach Mollusca community as a basis for effective conservation efforts. Data were collected through purposive sampling methods at three different locations, then analyzed using the Shannon-Wiener Index method, evenness index, and dominance index. The results showed that the North of Toronipa Beach had the highest diversity with a Simpson index of 0.91, followed by the West with 0.76, and the East with 0.75. These differences in diversity reflect variations in microhabitats, such as substrates, water flow, and human activities, which affect the distribution and abundance of species. This study highlights the importance of proper management and conservation to maintain biodiversity in Toronipa Beach and provides a basis for further studies on the impacts of the environment and climate change on coastal ecosystems.

Reforestation Impact: Contrasting Carbon Stock and Biodiversity of Clove in Monoculture and Mixed Gardens Over 25 Years

Tropical forests, vital for absorbing CO2 and maintaining ecosystem balance, are threatened by deforestation and unsustainable agricultural practices. Mixed garden or clove agroforestry systems, which combine clove cultivation with other crops, offer a sustainable alternative to traditional monoculture practices. This study aims to assess the biomass potential, carbon storage, and biodiversity in clove monoculture and mixed garden systems. The research was conducted in February 2024 at smallholder clove plantations and secondary forests in Pesaren, Sukorejo, Kendal, Central Java. The study involved primary data collection on clove monoculture and mixed garden systems using standardized plot sampling techniques. Biomass, carbon storage and carbon sequestration was calculated through field measurements utilizing allometric equations, while biodiversity was assessed using the Shannon-Wiener index based on species richness and evenness within the sampled plots. The mixed garden system closely approximates secondary forests in terms of biomass, carbon storage, CO2 sequestration, biodiversity, and species evenness, with respective values of 100.36 tons/ha, 47.17 tons/ha, 173.11 tons/ha, 2.837, and 0.91. In contrast, the clove monoculture system recorded the lowest values across all parameters: 67.03 tons/ha for biomass, 31.50 tons/ha for carbon storage, and 115.61 tons/ha for CO2 sequestration, with a dominance of one species and a Shannon-Wiener index and evenness value of 0. These results highlight the superior ecological benefits of mixed garden systems over monoculture clove plantations.

Compositional analysis of invertebrate communities in Raja Ampat conservation zones using environmental DNA (eDNA)

Raja Ampat conservation area is divided into three zones: the core zone, the tourism zone, and the open zone. This region is crucial for sustainable fisheries and environmental management, yet it is under significant anthropogenic pressure. Accurate species detection is essential for inventory and diversity surveys, and environmental DNA (eDNA) methods have been shown to be more effective than conventional techniques. This study aimed to evaluate whether V9 primers could detect multispecies invertebrate compositions, assess community structure and contributions within each zone, and identify significant differences in invertebrate diversity among the zones. A total of 66 eDNA samples were collected from water and sediment columns across the three zones. Samples were extracted using the NucleoSpin™ kit (Macherey-Nagel) protocol, amplified with universal eukaryote primers targeting the 18S gene, and sequenced using Illumina MiSeq. Taxonomic analysis was performed using QIIME2 software and the SILVA database. The study identified 19 invertebrate species. The Shannon-Wiener (H') and Simpson (D) indices revealed greater species diversity in the core zone compared to the tourism and open zones. However, the Kruskal-Wallis test indicated no significant differences in species diversity across the zones. SIMPER analysis demonstrated a high percent contribution of species in each zone. This study highlights the effectiveness of eDNA methods for biodiversity assessment and offers valuable insights into invertebrate community structures within the Raja Ampat conservation area.

An assessment of maintenance works and their impact on macroinvertebrate communities and long-term recolonization to small lowland watercourses

Due to their small size and high anthropogenic pressure, small watercourses are particularly prone to severe siltation and are densely overgrown with macrophytes. Many of these watercourses are subject to regular maintenance works (RMW), consisting of seasonal desilting and vegetation clearance, in order to ensure unobstructed water flow. The aim of the study was to assess the impact of three types of maintenance works: dredging and mud removal (DMR), river channel vegetation removal (RCVR) and river bank vegetation removal (RBVR) on taxa species richness, macroinvertebrate density and the Shannon-Wiener diversity index, as well as their changes and long-term benthic recolonization one and two years after completion of the works. The study was carried out in 21 habitats on eight rivers in the European Central Plains Ecoregion. A total of 107 zoobenthic taxa were found at all sites, and their species composition was characteristic of highly hydrophytic waters with low hydrological and hydrochemical quality parameters. A significant decrease in macroinvertebrate taxa richness was observed one year after the works, as the average number of taxa had dropped from thirteen to eight, with a further fall to seven taxa two years after the RMW. The same was true for density, which had decreased from an average of 2496 to 786 individuals per square meter one year after the RMW, while, a gradual recolonization was recorded two years after the RMW, with an average density of 1295 individuals per square meter. The Shannon-Wiener index, which had averaged 2.528 before the RMW, also decreased, falling to 1.982 and 1.832 one and two years after. BACI statistical analyses showed that of the three types of maintenance work, desilting and bottom sediment removal had the largest negative impact, significantly reducing taxonomic composition (by an average of 53%), density (by an average of 43%), and ecological index values (by an average of 40%). Over-frequent maintenance can prevent macroinvertebrate populations from recovering, thus depleting the environment of valuable taxa, including those that provide food for fish and other vertebrates.

PaRaVis: An automatic Python graphical package for ensemble analysis of plant beta diversity using remote sensing proxies

The ongoing impacts of climatic changes, coupled with intensified human activities, are leading to a significant loss of plant diversity, prompting urgent calls for comprehensive monitoring of forest ecosystems. This is particularly concerning in regions with the encroachment of human activities into forest zones, and inadequate regulations that primarily view forests as a source of timber without fully accounting for their critical roles in biodiversity. These issues highlight the need for effective geospatial approaches to support conservation strategies and sustained monitoring of plant diversity. The majority of remote sensing studies of plant diversity have focused on alpha-diversity, while beta-diversity plays an important role in providing a comprehensive picture of biodiversity patterns across scales. Among various remote sensing proxies, Rao's Q index stands out as a reliable metric to quantify beta-diversity using multispectral remote sensing indices. However, a holistic approach that can incorporate multiple remote sensing indices and enable comparative analysis using graphical means with computational efficiency is lacking. In response, we developed PaRaVis, an open-source Python-based graphical package for deriving spectral diversity from multispectral remote sensing datasets as a proxy for functional diversity using Rao's Q index. This tool encompasses all the necessary steps for parallelized computation, visualization, and analysis of Rao's index from either single or multiple multispectral indices. It is capable of calculating and visualizing 75 vegetation indices (VIs), from a raster scene, followed by calculating Rao's Q both unidimensionally and multidimensionally in parallel. PaRaVis also offers features for visualizing, analyzing, and comparing Rao's Q outputs using statistical performance diagnostics. It provides a unique means to infer diversity patterns in space and time and is therefore invaluable for researchers or organizations involved with plant diversity monitoring, especially those with limited data analysis or computer programming experience. To demonstrate the tool's effectiveness, we analyzed plant diversity patterns using satellite-derived spectral heterogeneity measures in forest sites within the Hyrcanian Forests of Iran and sites located in Germany. The first case study focused on UNESCO Natural Heritage sites. Our analysis revealed that employing EVI, SR3, and TCI indices as inputs for the multidimensional Rao's Q yielded higher performance in monitoring more heterogeneous forests compared to the unidimensional mode. In the second case study, we utilized field Species Richness and Shannon-Wiener diversity indices to evaluate PaRaVis and our method. We found that using a multi-temporal, multi-index approach enhances the results compared to multi-seasonal and classical Rao based on single time.

Stand spatial structural diversity: Developing and validating a novel index

Numerous studies related to the diversity-productivity relationships have mainly focused on the effects of species diversity, function diversity, and nonspatial structural diversity (e.g., variations of diameter), but have overlooked the significant roles of spatial structural diversity. Therefore, the motivation of the present study was to develop a comprehensive index of stand spatial structural diversity (H′) by integrating the strengths of the Shannon-Wiener index and the quaternion joint probability distribution of commonly used neighborhood-based parameters, namely the uniform angle index (W), mingling index (M), diameter dominance index (U) and crowdedness index (C). The application abilities of the index were tested using ten 100 m ×100 m sample plots that were distributed in three different climate zones [4 plots in Greater Khingan Mountains (GKM), 2 plots in Lesser Khingan Mountains (LKM), 4 plots in Changbai Mountains (CBM)] in Heilongjiang Province, northeast China. Meanwhile, the potential driving factors on stand spatial structural diversity were also detected using stepwise regression and hierarchical partitioning techniques based on 3000 simulated stands. The results indicated that the average values of H′ at GKM, LKM, and CBM were 0.8436, 0.8079, and 0.8098, suggesting that the stand spatial structural diversities of the forests in GKM were notably higher than those in LKM and CBM. The characteristics of M, C, and W emerged as the three most influential factors driving stand spatial structural diversity. This study contributes significantly not only by providing an effective index for measuring stand spatial structural diversity, but also by streamlining the complex decision processes associated with optimizing stand spatial structure.

Mapping Characteristics in Vaccinium uliginosum Populations Predicted Using Filtered Machine Learning Modeling

Bog bilberry (Vaccinium uliginosum L.) is considered a highly valued non-wood forest product (NWFP) species with edible and medicinal uses in East Asia. It grows in the northeastern forests of China, where stand attributes and structure jointly determine its population characteristics and individuals’ growth. Mapping the regional distributions of its population characteristics can be beneficial in the management of its natural resources, and this mapping should be predicted using machine learning modeling to obtain accurate results. In this study, a total of 60 stands were randomly chosen and screened to investigate natural bog bilberry populations in the eastern mountains of Heilongjiang and Jilin provinces in northeastern China. Individual height, canopy cover area, and fresh weight all increased in stands at higher latitudes, and shoot height was also higher in the eastern stands. The rootstock grove density showed a polynomial quadratic distribution pattern along increasing topographical gradients, resulting in a minimum density of 0.43–0.52 groves m−2 in stands in the southern part (44.3016° N, 129.4558° E) of Heilongjiang. Multivariate linear regression indicated that the bog bilberry density was depressed by host forest tree species diversity; this was assessed using both the Simpson and Shannon–Wiener indices, which also showed polynomial quadratic distribution patterns (with a modeling minimum of 0.27 and a maximum of 1.21, respectively) in response to the increase in latitude. Structural equation models identified positive contributions of tree diameter at breast height and latitude to shoot height and a negative contribution of longitude to the bog bilberry canopy area. Random forest modeling indicated that dense populations with heavy individuals were distributed in eastern Heilongjiang, and large-canopy individuals were distributed in Mudanjiang and Tonghua. In conclusion, bog bilberry populations showed better attributes in northeastern stands where host forest trees had low species diversity, but the dominant species had strong trunks.