Dominance Of Invasive Species Research Articles

Homogenization of soil seed bank communities by fire and invasive species in the Mojave Desert

Soil seed banks help maintain species diversity through temporal storage effects and function as germination pools that can optimize fitness across varying environmental conditions. These characteristics promote the persistence of native plant communities, yet disturbances such as fire and associated invasions by non-native species can disrupt these reserves, fundamentally altering successional trajectories. This may be particularly true in deserts, where native plant communities are less adapted to fire. While studies of fire effects on desert plant communities are not uncommon, information regarding the short- and long-term effects of fire on seed banks is less available. To better understand the influence of fire and invasive species on desert seed banks, we investigated soil seed bank biodiversity from 30 wildfires that burned between 1972 and 2010 across the Mojave Desert ecoregion of North America. We assessed how characteristics of fire regimes (frequency, time since fire, and burn severity) interacted with climate and invasive plants on measures of α-, β-, and γ-diversities. Because β-diversity is a direct measure of community variability and reveals important information about biodiversity loss, we further examined the nestedness and turnover components of β-diversity. Mean α- and γ-diversities were generally higher for burned locations than in unburned reference sites, however individual fire variables had little influence on patterns of seed bank diversity. Burned area seed banks tended to be dominated by non-native invasive species, primarily two grasses, (Bromus rubens, Bromus tectorum), as well as an invasive forb (Erodium cicutarium). The most striking pattern we observed was a collective sharp decline in α-, β-, and γ-diversities with increased invasive species dominance, indicating the homogenization of seed bank communities with the colonization of invasive species after fire. Evidence of homogenization was further supported by reduced turnover and increased nestedness in burn areas compared to reference areas indicating potential biodiversity loss. Our findings highlight how biological processes such as plant invasions can combine with disturbance from fire to alter patterns of seed bank composition and diversity in desert ecosystems.

Multiple invasions and predation: The impact of the crayfish Cherax quadricarinatus on invasive and native snails

AbstractThe pace of biological invasions has increased in recent decades, leading to multiple invasions and the potential dominance of invasive species, destabilizing local ecological networks. This provides opportunities to study new ecological species interactions, including predation. Tropical freshwaters have been particularly concerned by aquatic invasions and we focused here on the Martinique island (Lesser Antilles). We examined the predator–prey relationships involving invasive Thiarid snails (Tarebia granifera and Melanoides tuberculata) and the native Neritina punctulata, both confronted with a newcomer predator, the redclaw crayfish (Cherax quadricarinatus). We conducted several mesocosm experiments to assess the impact of crayfish predation on snail survival and the passive and active antipredator responses of snails. A first experiment indicated snail survival rates between 50% and 80%, depending on crayfish size and sex. Notably, there was a negative correlation between snail survival and male crayfish size and the predation method (shell crushing vs. “body sucking”) varied with crayfish size. The second experiment suggested no refuge size for snails, with both very small (<5 mm) and very large (>5 mm) unable to escape predation, regardless of crayfish size (from 77 to 138 mm) or sex. Finally, we investigated the escape behavior of Thiarids regarding three crayfish cues. Melanoides tuberculata tend to bury in the substrate and T. granifera to climb up aquarium walls, what was expected from their shell morphologies, and both responding to crayfish cues within minutes. Overall, C. quadricarinatus proves to be an efficient snail predator with limited escape options for snails, potentially contributing to the decline of certain snail populations in Martinique. This omnivorous predator might impact other native species across different groups, including shrimps and fish. Our study underscores the urgent need for monitoring efforts, solidifying the redclaw crayfish reputation as a dangerous invasive species for freshwater macrobenthic faunas worldwide.

Physico-chemical properties of Brazilian native bamboo species

Despite the worldwide social and economic importance of bamboos, most species have been poorly studied in areas with high species richness, such as Brazil. We conducted a physico-chemical characterization of four bamboo species native to southern Brazil. Merostachys skvortzovii Send. and Chusquea meyeriana Rupr. ex Döll are the most common and occur frequently as dominant invasive species, Apoclada simplex McClure & L.B.Sm. is listed as a threatened species, and Chusquea cf. gracilis is a rare species. Juvenile and adult samples were analyzed for moisture, ash, extractives, lignin, carbon (C), hydrogen (H), nitrogen (N), sulfur (S), silicon (Si), oxygen content (O), and inorganic analytes. Important differences were found between adults and juveniles and among the studied species. The results point to higher cellulose content for Chusquea cf. gracilis and C. meyeriana, while Chusquea meyeriana presented the greatest diversity of chemical elements. Overall, the results can inform the development of new applications of these species. This is particularly important for Merostachys skvortzovii and Chusquea meyeriana as they have widespread ecological importance and can arrest forest successional development in the region.

Cadmium induced defense enhance the invasive potential of Wedelia trilobata under herbivore infestation

Cadmium (Cd) pollution is on the rise due to rapid urbanization, which emphasize the potential adverse effects on plant biodiversity and human health. Wedelia as a dominant invasive species, is tested for its tolerance to Cd-toxicity and herbivore infestation. We investigate defense mechanism system of invasive Wedelia trilobata and its native congener Wedelia chinensis against the Cd-pollution and Spodoptera litura infestation. We found that Cd-toxicity significantly increase hydrogen peroxide (H2O2), Malondialdehyde (MDA) and hydroxyl ions (O2•) in W. chinensis 20.61%, 4.78% and 15.68% in leave and 27.44%, 25.52% and 30.88% in root, respectively. The photosynthetic pigments (Chla, Chla and Caro) and chlorophyll florescence (Fo and Fv/Fm) declined by (60.23%, 58.48% and 51.96%), and (73.29% and 55.75%) respectively in W. chinensis and (44.76%, 44.24% and 44.30%), and (54.66% and 45.36%) in W. trilobata under Cd treatment and S. litura. Invasive W. trilobata had higher enzymatic antioxidant SOD 126.9/71.64%, POD 97.24/94.92%, CAT 53.99/25.62% and APX 82.79/50.19%, and nonenzymatic antioxidant ASA 10.47/16.87%, DHA 15.07/27.88%, GSH 15.91/10.03% and GSSG 13.56/17.93% activity in leaf/root, respectively. Overall, W. trilobata accumulate higher Cd content 55.41%, 50.61% and 13.95% in root, shoot and leaf tissues respectively, than its native congener W. chinensis. While, nutrient profile of W. chinensis reveals less uptake of Fe, Cu and Zn than W. trilobata. W. trilobata showed efficient alleviation of oxidative damage through upregulating the genes related to key defense such as SOD, POD, CAT, APX, GR, PROL, FLV, ABA and JAZ, and metal transporter in leaves, shoot and root tissues, respectively. Conclusively, W. trilobata efficiently employed Cd-triggered defense for successful invasion, even under S. litura infestation, in Cd-contaminated soil.

Biodiversity: Net primary productivity relationships are eliminated by invasive species dominance.

Experiments often find that net primary productivity (NPP) increases with species richness when native species are considered. However, relationships may be altered by exotic (non-native) species, which are hypothesized to reduce richness but increase productivity (i.e., 'invasion-diversity-productivity paradox'). We compared richness-NPP relationships using a comparison of exotic versus native-dominated sites across the central USA, and two experiments under common environments. Aboveground NPP was measured using peak biomass clipping in all three studies, and belowground NPP was measured in one study with root ingrowth cores using root-free soil. In all studies, there was a significantly positive relationship between NPP and richness across native species-dominated sites and plots, but no relationship across exotic-dominated ones. These results indicate that relationships between NPP and richness depend on whether native or exotic species are dominant, and that exotic species are 'breaking the rules', altering richness-productivity and richness-C stock relationships after invasion.

Understanding the invasion potential of Chromolaena odorata and Lantana camara in the Western Ghats, India: An ecological niche modelling approach under current and future climatic scenarios

Invasive species are the major cause of native biodiversity loss and species extinction, which have predominantly affected one of the world's ‘hottest hotspots’ of biodiversity located in the Western Ghats, India with varied intensity. Therefore, in the present study, an investigation has been undertaken to model the potential habitat of dominant invasive plant species (IPSs) viz., Chromolaena odorata (L.) R.M.King & H.Rob. and Lantana camara L. in the Western Ghats, in the current and future climate change scenarios by evaluating the influence of the bioclimatic and topographical variables using species distribution modelling (SDM). The study exhibited the large invasion and proliferation of C. odorata (33.01%) and L. camara (30.33%) in the Western Ghats, especially the Nilgiri Biosphere Reserve (NBR) under the current scenario. The future projections derived using Shared Socioeconomic Pathways of Climate Scenarios datasets (SSPs 126, 245, 370, and 585) demonstrated a significant reduction in the invasion of C. odorata (>5.48% of WG), while a surge in the invasion of L. camara (>5.83% of WG) barring a few exceptions. However, the study highlighted the major future invasion of L. camara (45,262 sq. km; 31.33% under SSP 126 (2021–40)) and C. odorata (33,844 sq. km; 23.43% under SSP 245 (2021–40)) in the Western Ghats, of which large concentrations were observed in the NBR (L. camara: 5711 sq. km; 12.6%; C. odorata: 5090 sq. km; 15.04%) and the southern coasts. The study introduces a comprehensive and novel method leveraging SSPs of climate scenarios to identify the hotspots of major plant invasions in the Indian tropical forests using an ecological niche modelling. These findings hold significant relevance for prompt actions for invasion management in both current major hotspots and the regions susceptible to future invasions.

Alienated Species and Unsettled Ecologies: Locating “Redneck” Conservation in the Racial Discourse of “Asian” Carp Invasion

Abstract: Science studies scholars identify parallels between anti-immigrant and anti-invasive species rhetoric but have yet to consider how this linked racial discourse of invasion functions as part of a settler colonial project or what alternative forms of conservation arise through this confluence. Looking at this confluence through the lens of settler colonialism and Indigenous studies scholarship demonstrates how a form of environmental practice that I term “redneck” conservation reveals the racial and colonial logics of dominant invasive species discourses and practices. I propose the term alienated species to highlight these interconnections. Further, through a case study of “Asian” carp that explores social media, news media, and popular culture alongside Indigenous approaches, I argue that self-identified “redneck” settlers operationalize this discourse—alongside militaristic, masculinist embodiment—to position the “alien” as a foil against which they define whiteness and nativity while perpetuating Indigenous erasure. In this way, erasures of indigeneity and attacks against Asianness jointly produce the white male settled subject. In contrast, Indigenous communities engage a range of alternative responses to the carp and other alienated species within both formal land management strategies and everyday practices, such as harvesting. These responses reveal an Indigenous ethic of belonging that animates different ways of living on and providing care for the land, including the humans forced to live together.

Comparative study reveals management of a dominant invasive plant facilitates subtropical forest regeneration

Invasive plant species can drive ecosystem change, particularly on oceanic islands that are vulnerable to plant invasions and subsequent biodiversity loss. While invasive species management is vital for habitat restoration, efficacy of management efforts and the ability of native plants to regenerate varies among studies. The aim of this study was to examine the consequences of managing a thicket-forming woody plant species—Psidium cattleyanum Sabine (strawberry guava)—on subtropical forest regeneration, comparing spatial scales and management periods. We surveyed 15 locations on Norfolk Island, an isolated Pacific Island with a high proportion of endemic and threatened species, by establishing paired managed and unmanaged plots to assess changes in species-area relationships, abundance, richness, and composition of the plant community. Total plant richness was higher in managed plots at the largest scale examined (125 m2). However, there was no significant difference between managed and unmanaged plots in the slopes of species-area relationships when canopy, understory, and seedling strata were combined. Stratum-specific analyses revealed that management-driven changes were most evident in the subcanopy strata, which had significantly higher woody plant abundance and richness in managed plots. Compositional dissimilarity between managed and unmanaged plots was greater in locations with higher moisture levels, suggesting that post-management regeneration is related to environmental conditions. This study suggests that P. cattleyanum suppresses plant recruitment and its removal allows for forest regeneration, indicating that management of dominant invasive woody species facilitates plant recruitment on Norfolk Island if nearby native propagule sources are present.

Exploring the Structure of Static Net Fisheries in a Highly Invaded Region: The Case of Rhodes Island (Eastern Mediterranean)

Experimental fishing was conducted in three different locations along the coastal marine waters of eastern Rhodes Island, Levantine Sea, Hellas, from April 2021 to March 2022 on a monthly basis. Twelve samplings with gill nets and 12 with trammel nets at each of three selected locations resulted in a total of 72 samplings. The numbers of indigenous and non-indigenous species, as well as their abundances, biomasses and frequencies of occurrence, were recorded. Overall, the samplings yielded 71 species, of which 14 were non-indigenous. The total abundance was 1879 individuals, corresponding to a fish biomass of 433.57 kg. Fistularia commersonii, Sparisoma cretense and Pterois miles exhibited the highest numbers of individuals, whereas three of the invasive alien species in the Hellenic seas, namely, F. commersonii, Lagocephalus sceleratus and P. miles had the highest biomasses. The results exhibited a strong presence of P. miles in the Rhodian fisheries as the dominant invasive species based on the examined indicators (i.e., abundance, catches and frequency of occurrence). Comparisons in regard to the collected biomass between the locations, seasons, species origins and types of fishing gear were performed. All three locations were characterized by a good ecological status based on the relationship between abundance and biomass. The results of this study contribute valuable information on the ongoing changes in small-scale fisheries in the marine waters of Rhodes Island, which is one of the Eastern Mediterranean regions most affected by biological invasions.

A long‐established invasive species alters the functioning of benthic biofilms in lakes

Abstract Invasive species often transform environmental conditions, exclude native species and alter ecosystem functioning, including key ecosystem processes underpinning nutrient and energy cycles. However, such impacts have been most documented during periods of invasive species dominance; their influences on functioning at lower relative abundances and after long‐term establishment are less well‐known. We investigated the effects of Elodea canadensis, a macrophyte native to North America with a long invasion history in many regions of the world, on the biomass accrual and metabolism of littoral zone biofilms growing on organic and inorganic substrates. We deployed nutrient diffusing substrates (NDS) in 18 replicate transects distributed across six lakes, comprising three invaded by E. canadensis and three uninvaded reference lakes. NDS were amended with nitrogen (N), phosphorus (P) or N + P together, or were deployed as unamended controls. E. canadensis relative abundance varied widely in the invaded transects, ranging from 13% to 93% of all macrophyte cover. On control substrates, algal biomass, quantified as Chlorophyll‐a, and gross primary production (GPP) were 42% and 78% greater in the invaded compared to uninvaded lakes, respectively. Respiration rates, attributable to responses of both autotrophs and heterotrophs, were 45% greater on control substrates in invaded lakes. By contrast, N‐limitation of both biofilm GPP and respiration was 25% and 35% greater in uninvaded compared with invaded lakes. There was no evidence for differences in nutrients, light availability or grazing pressure between invaded and uninvaded transects. Rather, the observed differences in metabolism suggest that the presence of E. canadensis increases availability of N at local scales, reducing N‐limitation of biofilms and resulting in elevated rates of biofilm productivity. Our results demonstrate that invasive elodeids might have significant impacts on biofilms and processes associated with the cycling of nutrients, even when long‐established and present at lower relative abundances.

SPATIAL DISTRIBUTION OF INVASIVE PLANTS IN BANDUNG, WEST JAVA, INDONESIA

The urban area is a source of invasive plants that enter through human activities such as agriculture and land-use conversion. Studying the invasive plant in urban areas is essential to understanding the city’s ecosystem health condition. Therefore, this study aims to inventory invasive plants, map their distribution, and explain the relationship between land use with the community diversity and species richness of invasive plants in Bandung. The vegetation analysis was performed using line-transect in 22 study sites distributed using a systematic random sampling method in Bandung to observe the plant species composition. The study plots were placed based on the land-use type. The species name, individual number, frequency, and sampling site locations were noted and analyzed to calculate the important value index (IVI) and the invasive species distribution pattern using the principal component analysis (PCA). The dominant invasive species was spatially mapped. Six types of land use were used in this study, i.e., settlements, street green lanes, gardens, paddy fields, urban parks, and urban forests. There were 187 species found in Bandung, which can be categorized into alien invasive species (39%), invasive native plants (25%), non-invasive alien species (18%), non-invasive native species (15%), and unidentified plants (3%). The most common invasive plants found were Eleusine indica (IVI=10.50%), Trimezia martinicensis (IVI=7.22%), and Cyperus rotundus (IVI=6.74%). Based on the plant community similarity index, the study area with the highest similarities were paddy fields with gardens (50.5%), settlements with road lanes (44.4%), urban parks with road lanes (26.2%), and urban forests with road lane (17.5%). PCA showed Swietenia macrophylla as the most common invasive plant found in urban forests, urban parks, and road lanes, with air humidity as the most influencing environmental factor. Trimezia martinicensis is the most common species in the settlement area affected by high air humidity. Bidens pilosa is an invasive plant commonly found on paddy fields, gardens, settlements, road lanes, and urban park edges. This species can easily and rapidly reproduce with a high survival rate. The many invasive plants found in Bandung must be managed to maintain the urban ecosystem’s health.

Timing of invasive species removal influences nonnative biotic resistance and trajectories of community reassembly

Abstract As biological invasions increasingly threaten biodiversity, the removal of invasive nonnative species emerges as a possibility to recover the structure and function of native communities. Yet, we have limited knowledge of how communities assemble after nonnative removals. Since most ecosystems are invaded by multiple nonnative species, the impact of their removal likely depends on the interactions among nonnative species which, in turn, are contingent on the environmental context in which they occur. We evaluated the community assembly after the targeted removal of two highly invasive shrubs, Sweetbriar rose (Rosa rubiginosa) and Scotch broom (Cytisus scoparius). The removal was performed at two different times in the growing season (early or late removal) in field and mesocosm communities. In search of general patterns across species, we modelled species responses as a function of their origin (i.e. native/nonnative) and functional traits. We found evidence for negative and asymmetric interactions between dominant invasive species that translated into changes in the abundances of the rest of the species in the community. Depending on the identity of the removed species, the removal of invasive species affected community assembly by promoting other nonnative species or hindering the performance of native species. These effects were modulated by the timing of removal and did not depend on leaf or seed traits. Synthesis. Accounting for nonnative interactions and their temporal dependency should improve our inferences about assembly processes and the effectiveness of nonnative removal aimed at reducing the accumulation of nonnatives.

Climatic effect from oyster reef restoration in Spartina alterniflora invaded intertidal mudflat: From the perspective of CH4 and N2O production

Spartina alterniflora is a dominant invasive species along the coast of China. A surprising phenomenon that the oyster reef formation is substituting the S. alterniflora invasion, was recently observed in the west coast of Bohai Bay, North China. As the intertidal mudflat ecosystem is critical for coastal blue carbon, this paper aims to evaluate the climatic effect of the alternation from the perspective of potential CH4 and N2O production. The sediment geochemical properties and potential CH4 and N2O productions were therefore measured in sediments dominated by Spartina alterniflora (SA), oyster reef (OR), mixture of S. alterniflora and oyster reef (SA-OR) and bare mudflat (BM) at an intertidal mudflat. Meanwhile, sediment microbial community structure and function genes were also determined utilizing metagenome high-throughput sequencing technology. Our results indicated that the formation of oyster reef in S. alterniflora invaded intertidal mudflat might slightly reduce the sediment potential CH4 production and enhance the sediment potential N2O production. The oyster reef formation could alter the community composition of methanogens and the abundance of functional genes in methanogenesis, and transform the main pathway from methylotrophic to hydrogenotrophic methanogenesis in surface sediments. Metagenome sequencing revealed that the oyster reef formation may promote nitrification, inhibit dissimilatory nitrate reduction (DNRA) and nitrate assimilation functions, and reduce the abundance of nosZ genes. Mantel analysis showed that pH, soluble salt and dissolved carbon (DC) were the most important factors influencing the composition of microbial community. In general, our results imply that the growth of oyster reef in the S. alterniflora invaded area has opposing effects from the prospective of the potential CH4 and N2O production.

Komposisi, Dominansi, dan Pemanfaatan Gulma Agroforestri Jambu Mete (Anacardium occidentale L.) di Desa Gemawang Kecamatan Ngadirojo Kabupaten Wonogiri

Gemawang Village, Ngadirojo District, Wonogiri Regency, Central Java Province is home to one of the cashew (Anacardium occidentale L.)-based agroforestry operations. In agroforestry management, plants are one of the factors that can impede cashew production growth. To determine the success of weed control, it is necessary to first acquire an understanding of weed species. There were 2 stations in this study, namely cashew-based agroforestry ecosystem stations and teak monoculture ecosystems.This study assessed the composition, dominance, and prospective use of weed vegetation in cashew-based agroforestry areas. The point-intercept method and exploration of weed vegetation varieties in agroforestry station constitute the research methodology. As a comparison station, this study was also conducted on teak monocultures that are commonly found at research sites.The quadratic form measuring 1 m x 1 m with 100 grids of 12 plots at each station was utilised to collect weed samples. Composition and dominance of species in agroforestry and monoculture were found to be distinct. 24 species from 12 families are used in agroforestry, while 12 species from 7 families are used in monoculture. The dominant invasive species in agroforestry is Ageratum conyzoides L. (34.39%), while in monoculture it is Synedrella nodiflora Gaertn (37.78%). The weed vegetation diversity index value in agroforestry and monoculture was 1.90 and 1.51,respectively, which is considered moderate. In contrast, the value of the Sorensen uniformity index, which was 36.84%, was considered to be low. Up to 26 species of vegetation have the potential to contribute to human survival.

Exploration of Invasive Alien Plant Species on Habitat of Rhino in Icharni, Chitwan National Park, Nepal

The study was conducted with main purpose to assess the floral diversity and explore invasive species on rhinoceros habitat in two different research sites with in Chitwan National Park. The rhino is placed in the list of endangered species by International Union for Conservation of Nature and highly threatened due to loss their habitat by rapidly increasing invasive species. The study was done for a period of one month in (September to October) 2020. The 10 m, 5 m, and 1 m radius circular quadrates were utilized to gather data on trees, shrubs, and herbs, respectively. A total of 25 plant species were recorded from 15 plots. The importance values of each species of trees were analyzed. Seven species of invasive types were recoded from 15 plots (10 plots from riverine forest and 5 plots from grassland). Mikania micrantha was most dominant species with IVI 103.02 followed by Pogostemon benghalensis with IVI 78.93 and Chromolaena odorata with IVI 34.57 as the second and third most dominant invasive species respectively. The conclusion is that invasive species have an impact on the grassland and riverine forest, which are needed by the mega herbivore. The management of rhino habitat and the preservation of the rhino population are seriously threatened.

Effect of complete abolition of Eucalyptus species on under canopy species diversity in Gullele Botanic Garden, Ethiopia

Fast-growing, stress-tolerant tree species belonging to the genus Eucalyptus have historically been introduced in the central highlands of Ethiopia to support various economic and environment-regulating functions. While these non-native tree species are often highly useful, many are simultaneously invasive, generating negative environmental impacts and becoming the greatest global threat to biodiversity. This study is aimed at determining the impacts of the complete removal of the eucalyptus and its replacement by an indigenous species on the undergrowth vegetation of the Gulele Botanic Garden (GBG), Ethiopia. Vegetation data were collected from a total of 60 plots with a dimension of 20 m x 20 m that were laid out and equally distributed among invaded and indigenous species that dominate the landscape. Beside, diversity indices and population structural change parameters were employed for the comparison of changes. Results show that a total of 118 species (103 genera and 57 families) were recorded, and out of those, Eucalyptus camaldulensis was the most dominant species. On the other hand, the richest landscape (Juniperus procera plantation) contained 105 species and 51 families, whereas the poorest landscape (Eucalyptus plantation) was comprised of 66 species and 36 families. Furthermore, the alpha diversity index and vegetation vertical structure of the dominant Eucalyptus plantation differed significantly from those of other landscapes. Regeneration potential was not observed in Eucalyptus-dominant plantations since the inherent physiology of Eucalyptus species repels the regeneration of others. The population structure of the wood species showed an inverse-J curve. The total basal area (BA) of woody species decreased from 64.14 ± 1.54 m2 ha−1, 21.46 ± 0.54 m2 ha−1, and 17.18 m2 ha−1 ± 1.04 for Juniperus procera plantation, mixed plantation, and eucalyptus plantation, respectively. It was concluded that E. camaldulensis was one of the most dominant invasive species that reduced species diversity in the understory. While landscapes replaced after abolition by indigenous plantations demonstrated "fair" to "good" regeneration potential and an alpha diversity index.

Spatial E-PSR modelling for ecological sensitivity assessment for arid rangeland resilience and management

In semi-arid regions, land vulnerability and food security are crucial challenges for the scientific community, as millions of livestock keepers depend on rangeland ecosystem services. However, the Aravalli range is a fragile ecotonal arid ecosystem of western India, which acts as a barrier against the desertification of the Thar Desert. Besides increasing biotic pressure, land cover change, precipitation variability, and climate water deficits have a high potential to render the exploitation of resources unsustainable. This study is on the urgent basis addressing the sensitivity, fragility, and vulnerability status for rangeland ecosystem conservation management practices. Based on 17 distinct environmental indicators under five themes: topography, geo-climatic, socio-economic, ecological, and edaphic, which measure their susceptibility. Then, they evaluate their characteristics and sensitivity responses, as well as the resilience capabilities of the areas, utilizing the integrative methodology of the E-PSR (Ecosystem – Pressure, Sensitivity, and Resilience) model using a weightage decision matrix geostatistical approach. As a result, the study area is categorised into four eco-sensitive areas: I, II, III, and IV; they have an area of 4.1%, 62.5%, 32.2%, and 1.2%, respectively. As well, vulnerability reasons, i.e., human intervention, regulations, and management strategies for the arid rangeland ecosystem were discussed. To achieve eco-sensitivity and ecosystem stability in this study area, the government and conservationists must manage invasive species dominance and adjust buffer zones in reserve areas. In addition, study suggests using cutting-edge-technology for monitoring. In sum, this study helps governments and ecologists understand arid mountainous environments, their sensitivity and management.

Effects of land-use types and the exotic species, Hypochaeris radicata, on plant diversity in human-transformed landscapes of the biosphere reserve, Jeju Island, Korea

Land-use and plant invasion influence biodiversity. Understanding the effects of land-use types and invasive plants on the ecosystem is crucial for better management and the development of strategic plans for increasing biodiversity in Jeju Island, Korea, a designated Biosphere Reserve by the United Nations Education, Scientific, and Cultural Organization. The effect of the most dominant invasive exotic species, Hypochaeris radicata, on the four land-use types of Jeju Island was investigated. Plant composition, soil characteristics, and plant diversity among four land-use types (cropland, green space, neglected land, and residential) were compared. Among the land-use types, croplands had the most diverse plant composition and the highest richness in exotic and native plant species. Croplands, such as tangerine orchards, which are widely distributed throughout Jeju Island, showed the highest plant diversity because of medium intensity disturbance caused by weed removal. The relative cover of H. radicata did not differ between land-use types. However, H. radicata invasion was negatively related with plant species richness, making this invasive species a threat to the biodiversity of native herbs present in land-use areas. H. radicata adapts to areas with a broad range of soil properties and a variety of land-use types. Therefore, it is crucial to monitor land-use types and patterns of plant invasion to guide the implementation of consistent management and conservation strategies for maintaining ecosystem integrity of the transformed habitat in Jeju Island.

A Longitudinal Assessment of Benthic Macroinvertebrate Diversity and Water Quality along the Bronx River

The Bronx River is an urban waterway with a long history of anthropogenic disturbance. We conducted a longitudinal assessment of the Bronx River's water quality by measuring benthic macroinvertebrate diversity at 6 sites along the river. We integrated long-term water-quality data collected by the New York State Department of Environmental Conservation. We found that the overall water quality of the river has remained moderately impacted over different timepoints throughout the past 22 years. The study site upstream of combined sewage overflows and municipal separate stormwater systems exhibited healthier biological profiles, whereas the most-downstream sites exhibited slight declines in water quality. The most recent survey of the Bronx River (2020) revealed that high invasive species dominance was associated with benthic macroinvertebrate communities that were less healthy. Notably, one invasive species not documented in historical surveys, Corbicula fluminea (Asian Clam), was sampled in 5 of 6 study sites during the 2020 surveys. Moreover, no species were sampled from the order Ephemeroptera (mayflies) in 2020 despite being present in previous surveys. These results can be used to guide the management of urban rivers.

Impacts of Parthenium hysterophorus L. on Plant Species Diversity in Ginir District, Southeastern Ethiopia

Invasive alien species are considered the second greatest global threat to biodiversity. This study is aimed at determining the impacts of Parthenium hysterophorus on herbaceous and woody plant species diversity in the Ginir district, southeast Ethiopia. Data on vegetation were collected from the three study sites’ four land use types, with each land use type having invaded and non-invaded land units. A systematic random sampling method was used for establishing sampling plots. To examine the impacts of the invasive on native plant diversity, a total of 160 plots (120 plots of 1 m2 on grazing lands, roadsides, and abandoned agricultural lands and 40 plots of 20 m2 for sampling herbaceous and tree (shrub) species, respectively) were established. The number of plots was equally distributed in both invaded and adjacent non-invaded areas. Plant species from each plot were recorded and identified. In each plot, all the individuals of P. hysterophorus were counted, the heights of the five tallest individuals were measured, and the mean height was calculated. The percentage cover of P. hysterophorus was visually estimated. The data were analyzed using both descriptive and inferential statistics. A total of 105 plant species (45 trees/shrubs and 60 herbaceous) belonging to 84 genera and 42 families were documented in the study area. The result showed a strong negative relationship between the density of P. hysterophorus and other plant species richness (r = −0.82, p = 0.013) and species abundance (r = −0.917, p = 0.001) per study site of the invaded community. Species richness in the non-invaded site was higher (105 species) than in the invaded area (63 species), demonstrating the negative impact of P. hysterophorus on local biodiversity. Furthermore, the number of plant families was 42 in the non-invaded area, in contrast to only 32 in the invaded areas, a 23.8% decline. Of the plant communities, similarity indices between non-invaded and invaded sites among different land use types were >50%. It was concluded that P. hysterophorus was one of the most dominant invasive alien species in the study area that reduced the species diversity of various plant species. Putting in place a strategy and effective planning for the control and management of this invasive alien species is strongly recommended.