Occurrence In Habitats Research Articles

Effects of a Shallow Lake Condition Shift on Habitat, Zooplankton, and Yellow Perch Dynamics

AbstractAquatic ecosystems around the world exist on a continuum between turbid, algal‐dominated conditions and clear, macrophyte‐dominated conditions, which may influence population dynamics of fish in these systems (such as Yellow Perch Perca flavescens). Since turbidity influences the amount of light penetration and occurrence of vegetation, spawning and nursery habitat, as well as food availability, may change depending on lake condition. For example, a decrease in turbidity encourages a shift in the prevalent zooplankton taxa from Bosmina spp. to Daphnia spp. We hypothesized that many factors associated with a condition shift may combine to influence Yellow Perch, including increased abundance and therefore increased intraspecific competition, resulting in a reduced length and body condition. We used long‐term monitoring data from Lake Shaokatan, Minnesota, to examine whether a rarely documented condition shift from a turbid, algal‐dominated condition to a clear, macrophyte‐dominated condition occurred in 2014 and whether that shift influenced population dynamics of Yellow Perch, including relative abundance (gill‐net CPUE), mean total length, and mean relative weight. A condition shift from turbid to clear was determined in 2014 using mixed‐effects models that showed significant decreases in phosphorous and chlorophyll a concentration, as well as an increase from a mean of 22% to over 90% vegetation occurrence. The zooplankton community qualitatively showed a prevalence of Daphnia spp. and cyclopoids over small cladocerans during the clear condition period until 2018. Mixed‐effect models were also used to determine that the shift to a clear condition resulted in a significant decrease in Yellow Perch mean total length and relative weight. Therefore, the condition shift and resulting habitat changes that occurred in 2014 and later influenced the size and condition of Yellow Perch. Continued monitoring may overcome variability in relative abundance and help elucidate emerging trends.

Multisensor models for assessing recurrent fire compatibility with habitat recovery for a critically endangered species

The increased variety and availability of remotely sensed data from satellite and airborne platforms are expected to enhance data fusion approaches aimed at characterizing wildlife habitat. We investigated multisensor machine learning (ML) models to estimate desert grassland habitat suitability for a critically endangered species, the mask bobwhite quail (Colinus virginianus ridgewayi). Contemporary habitat conditions are marked by a history of intensive livestock grazing, periodic drought, and changes in arid land hydrology. Historical land use and vegetation changes were accompanied by altered disturbance regimes that once supported recurrent fire important to maintaining grassland composition and structure. Habitat assessment plots were combined with multidate and multispectral Worldview-3 (WV3) satellite imagery and airborne light detection and ranging (LiDAR) metrics to model habitat suitability on the Buenos Aires National Wildlife Refuge (BANWR). We used regression and structural equation models (SEM) to assess fire history, climate, and site biophysical effects on habitat suitability from 239 vegetation plots stratified by topography and fire frequency. We found that combined WV3/LiDAR models improved suitability predictions and consistency over WV3-only models comparing the root mean squared and mean absolute error from training data. Hyperparameter tuning for ML habitat models further improved performance. Gradient boosted regression trees and WV3/LiDAR habitat suitability models showed superior performance and correspondence to independent field validation data (F = 92.7, p ≤ 0.001, R2 = 0.57). Comparisons between predicted habitat suitability and fire history variables from 84 management units showed a significant negative relationship with increased fire frequency (F = 27.6, p ≤0.001, R2 = 0.41) and positive relationship with time since last burn (F = 41.3, p ≤0.001, R2 = 0.34). SEMs established that masked bobwhite habitat occurrence was strongly associated with site biophysical conditions that supported greater woody plant cover important for nesting, thermal, and predator protection. Our results suggest that desert grasslands associated with low primary productivity may require recovery periods in excess of 20 years to develop a desired mix of herbaceous and woody plant cover for masked bobwhite, when ≥2 fires have occurred over the last 30 years. Multiple sensor types provided a unique set of variables describing horizontal and vertical habitat structure and composition, essential to understanding fire effects on masked bobwhite habitat suitability. Combined information from active and passive remote sensing systems can likely enhance mapping and monitoring applications necessary for assessing recovery needs for numerous other wildlife species with diverse habitat requirements.

Biological Nitrogen Fixation in Sediments of a Cyanobacterial Bloom‐Occurring Bay in One Eutrophic Shallow Lake: Occurrence and Related Environmental Factors

AbstractBiological nitrogen fixation (BNF) is an important source of bioavailable nitrogen in the aquatic environment that supports primary production. However, little is known about its occurrence and potential in eutrophic freshwater habitats. This study investigated the diazotrophic diversity and seasonal variation of nitrogenase activity (NA) in the sediments of a cyanobacterial bloom‐occurring bay of a freshwater lake. Sequencing analysis of the nifH gene revealed that diazotrophs in Clusters I and III constituted the dominant components of the diazotrophic community in Meiliang Bay. Both nifH and 16S rRNA gene sequencing indicated that the microbes in sediments have different community structures during the winter than during other seasons. The concentrations of dissolved sulfide, sulfate, and nitrate in pore water were significantly correlated with NA in sediments; however, the Mantel test indicated that dissolved sulfide had a more significant effect on the structure of the diazotrophic community than did other environmental factors. Laboratory culture experiments under different redox conditions further confirmed the inhibitory effect of dissolved sulfide on BNF in sediments. This study revealed that the BNF in sediments of Meiliang Bay was closely linked to variations in dissolved sulfide concentration, which has broadened our understanding of BNF in freshwater lakes.

Spontaneous regeneration of Collembola assemblages in a raised bog after human-induced disturbance

Peatlands in anthropogenically transformed landscapes play an important role in biodiversity conservation. Most Baltic raised bogs have been completely destroyed by drainage and peat extraction. Collembolan and plant assemblages from an old peat mine (post-excavation pits and dykes overgrown by pine trees) were compared to those of intact ombrotrophic raised bog habitats (open bog and bog-pine forest) 70 years after excavation cessation. The plant cover and collembolan structure in regenerating pits were similar to those of the assemblages in natural open raised bogs. Rare tyrphobiont and tyrphofilous Collembola species occurred in both habitats. The assemblages in open bog habitats differed significantly from those in natural pine bog forest and dykes overgrown by pine trees. The assemblages of the natural open raised bog and pine bog forest were the most diverse and included numerous highly specialized Collembola species. The assemblages occurring on wooded dykes were significantly different from those at other peatland sites and were more similar to those of upland pine forests. The analysis of environmental factors (determined by moss Ellenberg numbers) showed that moisture was the most important factor affecting Collembola occurrence in natural and disturbed habitats. The occurrence of moss species also had a significant influence on the species composition of the collembolan assemblages. Our study revealed that seventy years of spontaneous ecosystem regeneration after peat excavation have led to habitat restoration for peat bog mesofauna. These results have important implications for conservation and restoration planning in disturbed peatlands.

New distribution record, ecology and tail trifurcation of Cyrtodactylus mamanwa (Gekkonidae) on Dinagat Islands, Philippines

This study highlights the ecology, natural history, and a new distribution record by providing a unique habitat occurrence record in karst ecosystem and describes a tail anomaly of the endemic Mamanwa Bent-toed GeckoCyrtodactylus mamanwain the province of Dinagat. The detection of a new population on Unib Island in the southwestern Dinagat extends the previously known distribution of this gekkonid by approximately 100 km south from its known distribution.

Diversity, Distribution, and Habitat Occurrence of the Diaptomid Copepods (Crustacea: Copepoda: Diaptomidae) in Freshwater Ecosystems of Thailand

The diversity, distribution, and checklist of diaptomid copepods from various freshwater ecosystems throughout Thailand are presented, based on data from our biodiversity projects during 1993–2019 and literature reviews. Thailand has one of the most diversified diaptomid fauna in the world, with 42 species identified from 2150 localities (4962 samples). Mongolodiaptomus has the highest species richness with ten species, followed by Tropodiaptomus with seven species. Among these, eight taxa (Arctodiaptomus sp., Mongolodiaptomus pectinidactylus, Neodiaptomus meggitti, Tropodiaptomus hebereri, T. lanaonus, T. oryzanus, T. ruttneri, and Paradiaptomus greeni) are new to the fauna of Thailand. The rare P. greeni, which predominantly occurs in Africa, is also a new record for Southeast Asia. The most frequently encountered species were Mongolodiaptomus botulifer, Phyllodiaptomus praedictus, M. calcarus, M. dumonti, M. malaindosinensis, Vietodiaptomus blachei, Phyllodiaptomus christineae, Eodiaptomus sanoamuangae, Neodiaptomus yangtsekiangensis, E. draconisignivomi, T. vicinus, and Heliodiaptomus elegans. Twelve species appear to be endemic to Thailand, and eight species occur only in the countries belonging to the lower Mekong River Basin (Thailand, Cambodia, Laos, and Vietnam). The uniqueness of the Thai diaptomids is a high degree of co-occurrence of four to seven species in the same localities. Comments on the taxonomic status of the species recorded are provided. In addition, the taxonomic validity of Mongolodiaptomus malaindosinensis is discussed.

The Possibility of Regenerating a Pine Stand through Natural Regeneration

Scots pine (Pinus sylvestris L.) is a widespread species in Eurasia, but its natural range can be significantly altered by a variety of stressors. The ability of pine to regenerate naturally is significantly reduced by its occurrence in unsuitable habitats. The processes of natural selection of pine from select habitats can be followed in stands of national parks where forestry activities are excluded. The possibility of pine regeneration is influenced by the following factors: characteristics of produced seeds, competition, and genetic characteristics. In the present study, selected factors associated with limiting the natural regeneration potential of pine were analysed. The present work generated important information related to the natural regeneration potential of pine in Central and Eastern Europe. The main objective of the analyses was to discuss the possibility of the natural regeneration of pine stands without human intervention. In addition, the genetic diversity of naturally germinating seedlings was analysed. The obtained results confirmed the high reproductive potential of pine despite the advanced age of the studied trees. The obtained seeds produced by old growth Scots pine trees had high viability, while a significant difference was observed in terms of the average number of cones per dominant tree between studied stands. Thus, the number of cones was the main element determining the regeneration potential of the stands. It should be emphasised that the number of cones did not influence the occurrence of natural regeneration. Based on the obtained results, the regeneration potential of pine stands depends mainly on the habitat and the competitive pressure. In addition, a correlation between genetic parameters and the regeneration potential of stands should be established, which may be the beginning of further research on the process discussed in this publication.

Multimodal deep learning for cetacean distribution modeling of fin whales (Balaenoptera physalus) in the western Mediterranean Sea

Cetacean Distribution Modeling (CDM) is used to quantify mobile marine species distributions and densities. It is essential to better understand and protect whales and their relatives. Current CDM approaches often fail in capturing general species-environment relationships, which would be valid within a broader range of environmental conditions that characterize the surveyed regions. This paper aims at investigating the usefulness of deep learning based schemes, namely multi-task and transfer learning, in CDM. Co-training of a stochastic presence-background model on a classification task and a deterministic rule-based model on a regression task was performed. Whale presence-only records were used for the first task, and index outputs of a feeding habitat occurrence model for the second one. This new approach has been experimented through the study case of fin whales in the western Mediterranean Sea. To evaluate our approach, a new metric called True Positive rate per unit of Surface Habitat (TPSH) and an original multimodal fully-connected neural networks were developed. A Generalized Additive Model (GAM)—a standard CDM method—was also used as a reference for performance. Results show that our multi-task learning model improves both the feeding habitat model by 10.8% and data-driven models such as GAM by 16.5% on our TPSH metric in relative terms, revealing a higher accuracy of our approach in estimating whale presence. Such trends in results have been further supported by the use of two other independent datasets that forced models to generalize beyond their training dataset of species-environment relationships. Performance could be further improved by adopting more optimal thresholds as observed from Receiver Operating Characteristic curves, e.g. the multi-task learning model could reach absolute gains up to 10% in the median of the True Positive Rate while maintaining its habitat spatial spreading. Globally, our work confirmed our working hypothesis that expert information on whale behaviour represent a good knowledge base for model generalization. This result can be further improved by a concurrent learning of more local species-environment relationships from in-situ presence data.

Synanthropic habitats of the Mediterranean recluse spider Loxosceles rufescens (Araneae: Sicariidae) in central Italy

The Mediterranean recluse spider Loxosceles rufescens (Dufour, 1820) is a public health concern due to its ability to inject venom that can cause skin lesions, referred to as loxoscelism. The spreading alarmism about recluse spiders which recently arose in Italy made it advisable to deepen knowledge about L. rufescens habitat preferences in human housing. Here, we report 14 confirmed cases of its occurrence in synanthropic habitats, and describe the housing characteristics. Our results pinpoint that traditional Italian houses of central Italy, in medieval towns and countryside, can be suitable for recluse spider colonization. The main features include the presence of walls of stone (with cracks and crevices), cellars, false ceilings, crawl spaces, wood materials (woodshed or wooden beams), and the occurrence of prey. Further characteristics which make conditions even more suitable are: large size, complex structure, and unoccupied premises. Due to its cryptic habits, even where L. rufescens is abundant, only the deployment of traps, following the recovery of a single or few individuals, revealed severe infestations. Our results confirm an unjustified negative notoriety of recluse spiders, considering that none of the inhabitants concerned, even if living in heavily infested housing, suffered from confirmed loxoscelism.

Impact of Salinity Changes in Shatt Al-Arab Estuary on Biodiversity of Marine Mammals of the Arabian Gulf: A Review

Salinity changes in the Shatt Al-Arab Estuary and North-West Arabian Gulf were monitored and reviewed in terms of the shortage of freshwater inflows to the Shatt Al-Arab Estuary. Data from previous and current surveys on marine mammals in the area have also been checked and compared to study the biodiversity under newly-developed circumstances. The Eco-physiological investigation was performed to assess the salinity tolerance limits of whales, dolphins and dugong. One-third of the world’s 81 species of whales and dolphins, collectively called cetaceans, are thought to occur off the shores in the area. The new checklist is prepared according to recent surveys in the neighbouring Arab Gulf countries and the known checklist of mammals in Iraqi waters. Spatial variation of the marine mammals of the southern part was governed by the occurrence of feeding habitats rather than a direct response to salinity variations. Alteration of seaweed’s habitats in response to water pollution is reported to have a direct effect on the biodiversity of mammals in the gulf. The results of this review were discussed in terms of salinity tolerance, hazardous ecological factors and spatial variation. No obvious effect of salinity changes imposed by the shortage of freshwater inflow on the distribution or loss of marine mammals neither on their habitat in the Arabian Gulf.

Similarity of ant communities increases with isolation from natural habitat and abundance of invasive ants in oil palm plantations of Central Borneo

Natural habitats can support insect diversity and shape their community structure in agroecosystems. The objective of this research was to investigate how proximity of natural habitat and invasive ant species influences the community structure of ants in oil palm plantations in Central Borneo, Indonesia. Twelve oil palm fields, at varying distances from areas of remaining forest or natural habitat, were selected as research plots. In each plot, insects were sampled using canopy knockdown fogging with a pyrethroid insecticide. In total, we found 62 canopy ant species belonging to six subfamilies. We found that Anoplolepis gracilipes (invasive species) and Oecophylla smaragdina were the most abundant ant species across all of our plots, and their abundances were not spatially correlated. Distance of oil palm fields to natural habitat did not affect species richness and abundance of ants, but affected ant community similarity. Based on the generalized linear models, the ant community similarity was not only affected by the distance to natural habitat but also affected by the abundance of A. gracilipes. A. gracilipes abundance also had a negative effect on other ant abundance especially O. smaragdina. In conclusion, the occurrence of natural habitats helps shape the similarity of ant community in oil palm plantations possibly via inhibits the abundance of invasive species.

Spatial and temporal scales of exposure and sensitivity drive mortality risk patterns across life stages

AbstractImpacts of increases in extreme heat events under climate change may differ across ontogeny for species with complex life cycles. Different life stages may (1) experience unequal levels of environmental stress that vary across space and time (exposure) and (2) have different stress tolerances (sensitivity). We used a field experiment to investigate whether exposure, sensitivity, and overall mortality risk differed between life stages of a marine foundation species (the mussel Mytilus californianus) across thermal conditions that vary in space (habitat, elevation, and site) and time (season) in southern California, USA. We deployed temperature loggers to document habitat‐specific exposure patterns, conducted laboratory thermal tolerance assays to calculate sensitivity, and performed field surveys to determine whether risk patterns were reflected in distributions. Exposure to extreme temperatures was highest in solitary habitats and during spring. Juvenile mussels were more sensitive to extreme heat than adults, and sensitivity for both life stages was highest in December and March. Risk was largely seasonal for juveniles but was more temporally variable for adults. Spatial occurrence patterns were congruent with risk assessments for both life stages (i.e., higher occurrence in lower risk habitats). These results highlight the importance of incorporating life stage and temporal dynamics when predicting impacts of climate change.

El Niño–Southern Oscillation impacts on jumbo squid habitat: Implication for fisheries management

Abstract Dosidicus gigas is an ecologically and economically important squid species extensively distributed in the eastern Pacific Ocean. Its habitat is extremely sensitive to climatic and environmental variability. The relationship between habitat pattern of D. gigas and El Niño–Southern Oscillation (ENSO, divided into the El Niño, ENSO‐neutral, and La Niña events) was assessed from 1950 to 2015, using a habitat suitability index (HSI) modelling approach including two crucial environmental variables: sea surface temperature (SST) and sea surface height anomaly (SSHA). On the basis of cross‐correlation analysis, it showed that both SST anomaly and SSHA were significantly positively related to the ENSO index. Moreover, a significantly negative association was found between the HSI values and the ENSO index. Due to the El Niño events, SST off Peru became higher and sea level rose, resulting in contracted areas of suitable SST and SSHA; consequently, suitable habitats for D. gigas dramatically decreased. In contrast, during the ENSO‐neutral and La Niña years, the extent of suitable SST and SSHA increased due to the colder water and lower sea level, and suitable habitat for D. gigas expanded. Moreover, the latitudinal gravity centre of HSI was significantly positively associated with the ENSO index. Relative to the ENSO‐neutral and La Niña years, a southward movement of the monthly preferred SST isotherm for D. gigas during the El Niño years could explain the occurrence of more suitable habitats in southern waters off Peru. These findings suggested that the ENSO event plays an important role in regulating environmental conditions off Peru and further affected the spatio‐temporal distribution of D. gigas habitat.

Potential habitat connectivity for Malayan gaur (Bos gaurus) in a fragmented forest area in Peninsular Malaysia

Aim: To predict the distribution of suitable habitats for Malayan gaur (Bos gaurus) at a highly fragmented forest area in Peninsular Malaysia and to identify the potential connectivity between suitable habitat patches. Methodology: Maximum entropy (MaxEnt) approach was used to predict the distribution of suitable habitats of the Malayan gaur. Gaur presence-only data and six environmental variables were collated for the habitat suitability modeling, and area under curve (AUC) value was used to estimate the performance of the model. The resulting model was then used to derive a potential connectivity map through least-cost analysis using Corridor Designer toolbox in ArcGIS 10.4. Results: The AUC value of the habitat suitability model was 0.84. Distance from urban areas indicated the highest relative contribution to the model (26.9%), followed by distance from water body (24.2%) land use (18.0%) elevation (14.3%), slope (14.0%) and lithology (2.6%). Predicted suitable habitats for gaur were found mostly in lowland forest areas, especially in the vicinity of rivers within forest reserves. A total of five wildland blocks were derived from the habitat suitability model, and several potential corridor swaths were identified connecting the wildland blocks. Interpretation: The absence of gaur occurrence in suitable habitats suggest that fragmented habitats greatly affected gaur distribution and population. Road network and agricultural lands are the major barriers of gaur movement as they are very sensitive towards disturbances and conflict. Thus, this research proposes potential connectivity at a regional scale for Malayan gaur for use in future planning in conservation, management and development.

Predicting distribution of malaria vector larval habitats in Ethiopia by integrating distributed hydrologic modeling with remotely sensed data

Larval source management has gained renewed interest as a malaria control strategy in Africa but the widespread and transient nature of larval breeding sites poses a challenge to its implementation. To address this problem, we propose combining an integrated high resolution (50 m) distributed hydrological model and remotely sensed data to simulate potential malaria vector aquatic habitats. The novelty of our approach lies in its consideration of irrigation practices and its ability to resolve complex ponding processes that contribute to potential larval habitats. The simulation was performed for the year of 2018 using ParFlow-Common Land Model (CLM) in a sugarcane plantation in the Oromia region, Ethiopia to examine the effects of rainfall and irrigation. The model was calibrated using field observations of larval habitats to successfully predict ponding at all surveyed locations from the validation dataset. Results show that without irrigation, at least half of the area inside the farms had a 40% probability of potential larval habitat occurrence. With irrigation, the probability increased to 56%. Irrigation dampened the seasonality of the potential larval habitats such that the peak larval habitat occurrence window during the rainy season was extended into the dry season. Furthermore, the stability of the habitats was prolonged, with a significant shift from semi-permanent to permanent habitats. Our study provides a hydrological perspective on the impact of environmental modification on malaria vector ecology, which can potentially inform malaria control strategies through better water management.

MicroRNA transcriptome analysis of oriental river prawn Macrobrachium nipponense in responding to starvation stress

Food deprivation or fasting is an important environmental factor, and a regular occurrence in both natural aquatic habitats and artificial ponds. However, the potential immunoregulatory mechanisms underlying starvation stress in crustaceans remain unclear. MicroRNAs (miRNAs) are a new class of non-coding RNAs that can regulate various biological processes, such as stress and immune responses. In the present work, miRNAs related to starvation stress responses and immune properties were identified and characterised in oriental river prawn Macrobrachium nipponense using high-throughput sequencing and bioinformatics analyses. Twelve small RNA libraries from hepatopancreas tissue were sequenced across four fasting stages lasting 0, 7, 14 or 21 days. In total, 550 miRNAs were identified including 198 putative novel miRNAs and 352 conserved miRNAs belonging to 57 families. Moreover, compared with expression levels at 0 days, 27, 27 and 43 miRNAs were differentially expressed (DE-miRNAs) at 7, 14 and 21 days, respectively. Among these, four DE-miRNAs (ame-miR-190-5p, dme-miR-307a-3p, hme-miR-2788-3p and novel_68) were co-expressed at all three timepoints. Furthermore, 661 target genes regulated by these DE-miRNAs were identified, and associated functional annotations were derived by GO enrichment and KEGG pathway analyses, which showed that most DE-miRNAs were mainly participated in metabolic processes and immune responses. Furthermore, 26 host DE-miRNAs potentially participated in interactions with white spot syndrome virus (WSSV) were identified by predicting and analysing target genes from WSSV. The further WSSV challenge under starvation stress showed that dme-miR-307a-3p played a part in the antiviral responses against WSSV. Our results demonstrate that dme-miR-307a-3p may play vital regulatory roles in responding to starvation stress and WSSV infection. The findings contribute new insight into the molecular mechanisms associated with immune responses to environmental stress in crustaceans.

不同积水生境对河南黄河湿地植物多样性的影响

湿地作为水陆交替的过渡地带，承担着重要的生态服务功能，湿地植物是生态功能作用发挥的基础。不同积水生境与湿地植物物种组成和分布关系密切。黄河流域是国家的重要生态屏障，湿地面积广阔，河南黄河湿地作为黄河湿地的重要组成部分，其积水生境对植物多样性的影响尚不清晰。为研究河南黄河湿地植物的多样性现状以及积水生境对其植物多样性的影响，采用样方和样线相结合的方法对河南省7个黄河湿地自然保护区中的湿地植物进行调查，共设置样方981个。重点分析了不同积水生境湿地植物的主要群系和物种组成，研究了各生境物种多样性和群落多样性特征（α多样性），对比了的不同积水生境植物物种组成相似性和群落间相似程度（β多样性），明确了各生境的植物物种排序和指示种。结果表明：（1）河南黄河湿地植物群系以草本群系为主，共发现188种湿地植物，分属56科，138属；（2）不同积水状况湿地植物物种丰富度大小依次为：季节性积水 > 永久性积水 > 间歇性积水 > 季节性水涝，主要群系总数与物种丰富度趋势表现一致；（3）不同积水生境湿地植物的物种组成存在显著差异，季节性积水和永久性积水生境中植物物种组成相似性和群落间相似程度最高，各积水生境均有明显的优势种和指示种。河南黄河湿地积水生境在不同流段差异显著，不同积水生境下植物多样性和主要植物群系有明显区别，进行湿地生态建设时，建议优先保护季节性积水生境，减少季节性水涝生境的产生，以达到维持物种多样性，发挥湿地最大生态价值的目的。;As a transitional zone between land and water, wetland plays an important role in ecological services. Wetland plants are the basis of ecological function. The composition and distribution of plant species are closely related to different water habitats. The Yellow River basin is an important ecological barrier for the country, and the wetland area is vast. The Yellow River wetland in Henan is an important part of the Yellow River wetland. However, the effects of waterlogged habitats on plant diversity are still unclear. In order to study the plant diversity of the Yellow River wetland in Henan Province and the influence of waterlogging habitats on its plant diversity, we utilized the method of combining quadrat and transect to investigate wetland plants in seven Yellow River wetland nature reserves in Henan Province. In these reserves, a total of 981 quadrats were set for investigation. This research focused on analyzing the composition of main flora and species of wetland plants in different waterlogging habitats. Therefore, we studied the characteristics of species diversity and community diversity (α diversity) in different habitats, and compared the similarity of plant species composition and degree of similarity between communities (β diversity) in different waterlogging habitats. Moreover, the sequence and indicator species of plant species in the seven habitats were also clearly identified. The results show that:(1) Herbaceous flora is the main flora in Henan Yellow River wetland. A total of 188 species of wetland plants, belonging to 138 genera and 56 families, were found. (2) Under different standing water conditions, the plant species richness was in the order of seasonal ponding > permanent ponding > intermittent ponding > seasonal waterlogging. In addtion, the total number of major communities was consistent with the trend of species richness. (3) There are significant differences in plant species composition among different waterlogging habitats. The similarity of plant species composition and communities between seasonal ponding and permanent ponding habitats was the highest. There were obvious dominant species and indicator species in each waterlogging habitat. The hydrological habitats of the Yellow River wetland in Henan province were significantly different in different flow segments. There are obvious differences of plant diversity and main plant groups in different waterlogging habitats in the Yellow River wetland in Henan province. Under the circumstances, we suggest giving priority to the protection of seasonal ponding habitats and reducing the occurrence of seasonal waterlogging habitats during wetland ecological construction, so that we can achieve the purpose of maintaining species diversity and giving full play to the maximum ecological value of wetlands.

Ornamental potential of species from the ferruginous Campo rupestre of the Carajás National Forest, Brazilian Amazon

The flora of the ferruginous Campo rupestre that occur over the immense iron deposits of the Carajás National Forest is very unique, with several endemic and rare species. This vegetation is directly affected by mining activity, as a result of vegetation suppression and the profound disfigurement of habitats. The objective of this work was to identify the ornamental potential of the flora of the ferruginous Campo rupestre, as a strategy for ex situ conservation of ecosystem species. The species present in ten plots of 5 x 5 m were surveyed in different areas of the ferruginous Campo rupestre on the N1 plateau and the ornamental potential of each species was evaluated following a characterization key, considering morphology and habitat of occurrence. Subsequently, the species were compared with those already present on the market, as ornamental, based on the literature and on sites specialized in the sale of ornamental plants in Brazil. A total of 33 species with ornamental potential were found, distributed in 32 genera and 19 families. Most species showed high functionality for ornamentation and similarity with nationally consolidated ornamentals. Catasetum planiceps, Cyrtopodium andersonii, Epidendrum nocturnum, Mandevilla scabra, Norantea guianensis and Sobralia liliastrum have a consolidated ornamental market. The data collected support ex situ conservation strategies of the flora of the ferruginous Campo rupestre, such as its valorization, local commercialization and income generation for small extractivists in the region.

Aquatic habitat changes within the channelized and impounded Arkansas River, Arkansas, USA

AbstractRiver‐wide changes in morphologic character following channelization and impoundment alter the occurrence and distribution of surface water and available habitats for aquatic organisms. Quantifying patterns of creation, redistribution or disappearance of habitats at river‐wide and decadal spatiotemporal scales can promote understanding regarding trajectories of different habitat types following alteration and prospects of direct habitat enhancement projects within altered alluvial rivers. Newly available remote‐sensing tools and databases may improve detection of river‐wide changes in habitat through time. We used a combination of remote‐sensing data and generalized linear models to assess changes in surface water coverage from 1984 to 2015 among aquatic habitats of 496 km of the Arkansas River within Arkansas, USA. Changes through time in surface area of permanent and episodically inundated areas — and thus the availability of aquatic habitat — were variable along the river. Overall, the river lost a total 2.1% of permanent and 12.1% of episodic water surface area. The general trend of loss of off‐main‐channel habitat and increased coverage of permanent water along main‐channel habitats may indicate a long‐term transition (i.e. ramp‐type disturbance) within areas of the Arkansas River where backwaters are transitioning to terrestrial environments, and habitat heterogeneity in the main channel is decreasing. As such, a decadal‐scale change of channel form and backwater habitats may be the dominant pattern with limited regeneration of diverse habitat types. Understanding changes to permanent and episodic water availability may aid predictions regarding ecological effects of channelization and impoundments, including both increases and decreases in riverine productivity, biotic diversity and population abundances through space and time. Water resource managers and biologists can use information regarding river‐wide changes in habitat availability obtained through remote sensing data to direct river management practices, including dredging and side‐channel construction, and to assess ecological responses to such changes.

River Restoration as a Method Towards Harmonization of Natural Habitats in the Context of Ecological Corridors Preservation: A Case Study on the Hron River

Natural profile of the streams was conditional to the anthropological intervention, to channelling (canalization) of the watercourses due to the gradual settlement. The mentioned approach was involved because of the flood protection of residential areas, groundwater level adjustment, riverbed stabilization, etc. Corresponding anthropogenic interventions led to the devastation of several ecosystems and ecological corridors and their functions, occurring in the natural landscape environment. Consequently, rivers acquired new hydrological, hydraulic and biological parameters. The necessity of policy reaction led to the establishment of a framework for conservation areas, known as Natura 2000, in order to protect the threatened species and natural habitats. This article presents a case study based on a project aimed at the renewal of the flow-through of the blind river channel of the Hron river (in Slovakia) in its natural, historical channel’s route with the length of 570 m and the width between 10-15 m. The aim of restoration of the river’s arm included the recovery of aquatic habitats and stabilization of the floodplain area in the ecological corridor of the Hron river in the context of the efforts of the European Union (EU) towards strengthening harmonization of the interest of nature and human activities. Restoration of the blind river channel required an integrated approach and cooperation of key stakeholders, Slovak Water Management Enterprise, state owner enterprise and municipality of Rudno nad Hronom. As the areas of the old channels of riverbeds represent an important type of ecosystem, the process of their restoration needs to be planned properly. Planning the process consists of preparing detailed analyses of the current state of the bio-corridor with a focus on analysing the occurrence of vegetation and animal habitats, their combination and interaction. The connection between the ecological landscape and spatial planning leads to maximizing of benefits of the restoration, with the least possible interventions on the natural environment. Such an approach is fundamental regarding the harmonization and ecological connectivity between the natural and anthropogenic environment in the contexts of a sustainable strategy for the management and preservation of ecological corridors. The river’s channels are important ecological corridors of the natural environment of each country not only because of the water supply for adjacent floodplain areas but also because of the slowing down of water outflow from the environment and conservation of the richness of aquatic and terrestrial habitats. Revitalization and maintenance of the river flows are essential for the preservation and reconnection of the existing bio-corridors in accordance with the European Green Deal (2019) and help the natural environment in adaptation to occurring climate change.