Rich Habitats Research Articles

Of goats and heat, the differential impact of summer temperature on habitat selection and activity patterns in mountain goats of different ecotypes.

Climate change disproportionately affects northern and alpine environments, with faster rates of warming than the global average. Because alpine and northern species are particularly well adapted to cool temperatures, most species must modify their behavior when temperatures exceed a critical threshold. Evaluating how temperature increases affect species inhabiting northern and alpine environments is therefore essential to understand the effects of projected climate change on these ecosystems. We analyzed the influence of temperature on the activity patterns and habitat selection of four populations of a cold-adapted, mountain specialist, the mountain goat (Oreamnos americanus). We collected GPS location and activity sensor data during 2010-2019 from 223 mountain goats from two distinct ecotypes: coastal and continental. Using a resource selection modeling approach, we determined that mountain goats of both ecotypes decreased selection for alpine meadows when temperatures increased. Reduced selection for open, forage rich habitat was associated with increased selection for habitat dominated by snow/ice patches in coastal areas, and by forests in continental sites. Mountain goats in continental environments selected higher elevation habitats only when temperature increased, whereas goats in coastal environments selected higher elevation habitat at all temperatures. Mountain goats of both ecotypes reduced the proportion of time spent active when temperatures increased during the middle of the day. Our study reveals that mountain goats use diverse tactics to mitigate thermal stress, and that these tactics vary between ecotypes, highlighting the need for considering adaptation to specific environments within a species when assessing climate change impacts on populations.

High Resource Overlap and a Consistently Generalised Pattern of Interactions in a Bat-Flower Network in a Seasonally Dry Landscape.

Pollination is an ecosystem process that is crucial to maintain biodiversity and ecosystem function. Bats are important pollinators in the tropics and are an integral part of complex plant-pollinator interaction networks. However, network analysis-based approaches are still scarce at the plant species and bat community levels. We used metabarcoding to identify plant taxa present in pollen from fur and faecal samples collected across 1 year from three nectar-feeding bat roosts in central Mexico. We calculated the frequency of occurrence of plant taxa and assembled a zoocentric network of bat-plant interactions. We constructed a year-long network, encompassing the entire period of sampling, two seasonal networks comprising the wet and dry seasons, and six individual networks from sampling at two-month intervals across the year. Four species of nectar-feeding bats interacted with 36 plant species from 16 families. We found highly generalised interaction patterns across networks corresponding with opportunistic feeding behaviour by bats, with little seasonal variation in network structure. There was high resource overlap between bat species, and bats visited a diverse range of plant species even during periods with a high abundance of particular resources in the landscape. The diverse diet of nectar-feeding bats emphasises the importance of floristically rich natural habitats in the landscape to provide reliable foraging resources year-round in a seasonally variable system. While a generalised network structure is thought to increase robustness, further research is necessary to understand how fluctuations in pollinator abundance and diversity in the face of land use and climate change may impact bat-flower networks and the consequences to plant communities.

Predicting the effect of climate change and management on net carbon sequestration in the forest ecosystems of the European part of Russia with the complex of models

The objectives of sustainable development require the ability to estimate potential changes in net carbon sequestration in forest ecosystems (including changes in biomass, mortmass, and soil organic matter) under possible climate change and different forest management strategies. Such estimates require consideration of different ecosystem components and processes. To achieve this goal, we have integrated several ecological models (dynamic stand model FORRUS-S, soil organic matter model Romul_Hum, statistical climate generator SCLISS and process-based forest ecosystem model EFIMOD3) to simulate the ecosystem dynamics at the regional level in several study areas within the forest zone of the European part of Russia. The simulation results reflected both the direct effects of climate change and forest management actions on ecosystem carbon pools, and the indirect effects through changes in species composition. The simulation experiments were spatially detailed at the level of individual forest management units, thereby revealing the influence of habitat conditions on the rate of carbon sequestration under the influence of environmental factors. We found that net carbon sequestration in all major ecosystem pools was mostly positive, ranging between 0 and 1.45 t ha year−1 depending on study area and simulation scenario. Higher accumulation was typically observed in medium-rich and rich habitat types with mesic moistening. In the long term, the effect of climate change was found to be comparable to the effect of management interventions.

Achieving structural heterogeneity and high multi-taxon biodiversity in managed forest ecosystems: a European review

AbstractThe European Biodiversity Strategy has set the key goal to maintain and promote biodiversity. Managed forests here play a key role, as they are among the most diverse ecosystems. To create biodiversity rich managed forest landscapes, we need a deep understanding on how management affects forest structure and subsequently habitat quality on the local and landscape level. However, to date a confusingly large amount of different terms for various management systems exist and it remains unclear how forest structure and composition affected by specific management systems affect biodiversity. Here, we first aim to clarify forest management systems terminology. Second, we link existing management systems with forest structure and review at European level how these structures affect local α-, as well as landscape-scale β- and γ-biodiversity. We found that research and derived management guidelines have a strong focus on local forest stand heterogeneity and related α-diversity, while ignoring the importance of landscape-scale heterogeneity and therefore β- and γ-diversity. Instead of promoting one management system as an all-in-one-solution, a diversity of different forest management systems seems the most promising way to create biodiversity rich forest landscapes. We finally discuss how a combination of different management systems might help to create structurally rich forest habitats and landscapes, simulating different successional stages and promoting species rich communities.

Genome mining for ribosomally synthesized and post-translationally modified peptides (RiPPs) in Streptomyces bacteria

Ribosomally synthesized post-translationally modified peptides (RiPPs) are a novel category of bioactive natural products (NPs). Streptomyces bacteria are a potential source of many bioactive NPs. Limited opportunities are available to characterize all the bioactive NP gene clusters. In this study, 410 sequences of Streptomyces were analyzed for RiPPs through genome mining using the National Center for Biotechnology Information (NCBI), by combining BAGEL and anti-SMASH. A total of 4098 RiPPs were found; including both classified (lanthipeptide, RiPP-like, bacteriocin, LAPs, lassopeptide, thiopeptides) and nonclassified RiPPs. Soil was identified as a rich habitat for RiPPs. These data may offer alternative future remedies for various health issues.

Intertidal and shallow subtidal marine tardigrades from the British Virgin Islands with a description of a new Batillipes (Heterotardigrada: Batillipedidae)

This is the first survey of marine tardigrades from the British Virgin Islands, though two species were previously reported from St. Croix, U.S. Virgin Islands. In June 2016, we collected subtidal and intertidal sand samples from various locations throughout the British Virgin Islands. We found 602 tardigrades in 18 of 21 samples, and these included 12 taxa, one of which, Batillipes wyedeleinorum sp. nov., is new to science and described here. We compared abundance and species diversity in intertidal and subtidal samples and found significantly greater abundance in intertidal habitats but no significant difference in the number of observed species between the two habitats. We calculated Chao 1 species richness, which indicated higher estimated richness in intertidal habitats and 15 ± 3.7 species (x̅ ± SD) in both habitats combined. Non-metric Multidimensional Scaling revealed differences in species composition between the two habitats with some species showing clear preferences for one or the other.

Food patch selection by the largest European herbivore

AbstractThe scaling relationship between digestive system and body mass shapes foraging strategies in herbivores. The Jarman–Bell principle and the forage maturation hypothesis (FMH), two of the most important predictions formulated in herbivore foraging ecology, have been used to explain this relationship.We aimed to test these predictions for the largest European herbivore—the European bison-which is highly sexually dimorphic and recognised as a refugee species in non-optimal forest habitats. We conducted our study in the Białowieża Primeval Forest, where the European bison has been recognized as a refugee species. We estimated vegetation quality and biomass along the foraging paths of male and female European bison, and the vegetation biomass at random points in different habitats and months. We found no support for the Jarmann-Bell principle at the intraspecific level in European bison, as males and females foraged on patches of similar crude protein and fibre content. However, females selected for higher biomass. The quality of vegetation on the bison foraging patches showed a significant spatio-temporal variation. It increased from May to July and then gradually decreased. It also increased with the fertility and wetness of the habitats being the highest in wet forests. Mean biomass on European bison foraging patches (131.5 g/m2), was significantly lower than on random plots (210.5 g/m2), which supported the FMH. Our study suggests that in rich forest habitats, the abundant food resources available in summer may not constrain the metabolic rate/gut capacity ratio of either sex, potentially leading to dietary segregation. In contrast to open habitats, where vegetation maturation is less temporally variable, European bison in rich forest habitats may optimise patch selection and energy intake by tracking a habitat- and species-specific changes in the plant phenology. Understanding the relationship between European bison forage selection and forage nutritional constraints in forest habitats may be critical for conservation programmes, as European bison are better adapted to more open habitats and are recognised as refugee species in suboptimal forest habitats.

Quantifying the effects of landscape and habitat characteristics on structuring bird assemblages in urban habitat patches

Understanding the determinants of biodiversity in fragmented habitats is fundamental for informing sustainable landscape development, especially in urban landscapes that substantially fragment natural habitat. However, the relative roles of landscape and habitat characteristics, as emphasized by two competing frameworks (the island biogeography theory and the habitat diversity hypothesis), in structuring species assemblages in fragmented habitats have not been fully explored. This study investigated bird assemblages at 26 habitat patches (ranging in size from 0.3 to 290.4 ha) in an urban landscape, southwest China, among which habitat type composition and woody plant species composition varied significantly. Through 14 bird surveys conducted over six breeding seasons from 2017 to 2022, we recorded 70 breeding bird species (excluding birds recorded only once and fly-overs, such as raptors, swallows and swifts), with an average of 26 ± 10 (SD) species per patch. We found that patch area had significant direct and indirect effects on bird richness, with the indirect effects mediated by habitat richness (i.e., the number of habitat types). Isolation (measured as the distance to the nearest patch), perimeter to area ratio (PAR), and woody plant richness did not significantly predict variation in bird richness. Furthermore, none of these factors significantly sorted bird species based on their functional traits. However, the overall makeup of bird assemblages was significantly associated with the specific habitat types and woody plant species present in the patches. The results suggest that neither the island biogeography theory nor the habitat diversity hypothesis can fully explain the impacts of habitat fragmentation on bird richness in our study system, with their roles primarily being linked to patch area. The findings that habitat and plant compositions were the major drivers of variation in bird assemblage composition offer valuable insights into urban planning and green initiatives. Conservation efforts should focus not only on preserving large areas, but also on preventing urban monocultures by promoting diverse habitats within those areas, contributing to the persistence of meta-communities.

Competition between alien and native species in xerothermic steno-Mediterranean grasslands: Cenchrus setaceus and Hyparrhenia hirta in Sicily and southern Italy

AbstractPerennial dry grassland communities, vital for plant biodiversity conservation in the Mediterranean, often harbor rare and endangered species. However, these habitats face threats, including the invasion of alien species. Cenchrus setaceus, a highly invasive grass, is spreading in the Mediterranean region. Historical records and observations document its establishment and invasiveness across various Italian regions. This study investigates the impact of C. setaceus on native grasslands dominated by Hyparrhenia hirta. We assessed the impact of C. setaceus invasion on plant biodiversity in Sicily and southern Italy, and we identified and characterized plant species’ composition using Ellenberg indicator values. The intention to analyze species richness, diversity, and ecological indicators is also emphasized. Starting from the use of the phytosociological method, multivariate analysis and Ellenberg indicator values to assess the impact of C. setaceus on grasslands composition were considered. There are several similarities and differences in diversity, floristic composition, and ecological traits between the two grassland types. A deep comparison with central European studies and evaluation of the impact of C. setaceus on species richness and community dynamics in Mediterranean habitats were concluded. Although C. setaceus is invading native grasslands, it does not drastically reduce species richness. The ecological implications of the invasion are explored, urging ongoing monitoring and collaborative efforts for effective conservation. The importance of interdisciplinary cooperation is highlighted to address the threat of invasive species and sustain the biodiversity of Mediterranean grasslands.

Comparative foraging behavior of 3 heron species in small standing-water ecosystems in the arid zone of Oman

Abstract The composition of assemblages, diet and behavior of waterbird species with similar ecological features are important aspects in the functioning of aquatic ecosystems. Closely related animal species often share resources such as space and food in ways that reduce competition, but if the diets of different species strongly overlap, interspecific competition may intensify. This analysis examined behavioral data relating to Great Egret, Little Egret, and Squacco Heron to explore their foraging efficiencies in rich aquatic habitats in an arid zone during post-breeding movements. The fieldwork was carried out in small estuaries of a Wadi on the southern coast of Oman. The frequency of interactions was the highest in Squacco Heron and the lowest in Great Egret. However, the differences in the numbers of inter- and intra-specific interactions between the 3 species were significant. Activity indices calculated for a 5-min period, i.e., the number of interactions (interaction index) and times of flying and walking (movement index) differed among the 3 species. The number of successful attacks was the highest in Squacco Heron, while the foraging effectiveness of Great Egret and Little Egret was similar. GLM analysis showed that only the movement index was significant, as it had a positive impact on individual foraging success. Great Egret caught more fish than the other 2 heron species which, in turn, caught a greater number of smaller prey items, mostly invertebrates. This study shows that heron species in the same rich habitat employ different foraging tactics. In comparison to the other two heron species, the foraging tactics of Squacco Heron seem to be the most susceptible to competition. However, its greater mobility and using different foraging tactics, enhance its foraging success.

Episodic deterioration of plant diversity in rich fens with or without in situ oil sands exploration disturbance

Peatlands with ground surfaces near the water table may be sensitive to disturbances that reduce this distance to water. Shrubby rich fens (SRF) in northern Alberta, Canada, are restricted to the wettest landscape positions and are characterized by brown mosses and stunted trees on weakly consolidated and saturated substrates. In situ oil sands exploration (OSE) practices have established thousands of drilling pads to explore for deeply buried bitumen deposits, with many located on peatlands. In the development of OSE pads on peatlands, the vegetation layer is removed, eliminating the functionally important hummock‐hollow surface topography. We examined the spontaneous regeneration of bryophytes and vascular plants and surface microtopography on SRF, 7 and again 14 years after pad abandonment. In both sampling years, drilling pad surfaces were closer to the water table (mean pad elevation 2012 = 3.3 cm, 2019 = 5.6 cm) and had minor topography compared to adjacent reference habitat. We found, however, over the 7 years, that for both drilling pads and reference habitat, bryophyte and vascular plant richness decreased, and most species declined in frequency. Furthermore, for pads and reference habitat, density of tree seedlings decreased, and expansion of hummock‐forming mosses was limited. Findings suggest that drilling pads and their natural counterparts on SRF may be prone to episodic reductions in plant diversity and ecosystem retrogression, likely resulting from prolonged surface saturation during summers with high rainfall. Because of their wet landscape positions and environmental vulnerability, SRF are likely the peatland habitats slowest to recover following OSE pad construction.

Aging behavior and leaching characteristics of microfibers in landfill leachate: Important role of surface mesh structure

Mesh-structured films formed by the post-processing of microfibers improves their permeability and dexterity, such as disposable masks. However, the aging behavior and potential risks of mesh-structured microfibers (MS-MFs) in landfill leachate remain poorly understood. Herein, the aging behavior and mechanisms of MS-MFs and ordinary polypropylene-films (PP-films) microplastics, as well as their leaching concerning dissolved organic matter (DOM) in landfill leachate were investigated. Results revealed that MS-MFs underwent more significant physicochemical changes than PP-films during the aging process in landfill leachate, due to their rich porous habitats. An important factor in the photoaging of MS-MFs was related to reactive oxygen species produced by DOM, and this process was promoted by photoelectrons under UV irradiation. Compared with PP-films, MS-MFs released more DOM and nano-plastics fragments into landfill leachate, altering the composition and molecular weight of DOM. Aged MS-MFs-DOM generated new components, and humus-like substances produced by photochemistry showed the largest increase. Correlation analysis revealed that leached DOM was positively correlated with oxygen-containing groups accumulated in aged MS-MFs. Overall, MS-MFs will bring higher environmental risks and become a new long-term source of DOM contaminants in landfill leachate. This study provides new insights into the impact of novel microfibers on landfill leachate carbon dynamics.

Habitat Characterisation for the Macro Moth Fauna (Lepidoptera: Heterocera) of the Cachar District of Southern Assam, India

The study conducted in the Cachar district involved a comprehensive characterisation of the local flora, identifying a total of 146 tree species from 50 families. The average species richness among tree species in moth habitats was estimated to be S=47.94±9.84. Dominant tree species found across all study sites in the Cachar district included Lagerstroemia reginae Roxb., Michelia champaca L., Tectona grandis L.f., Bombax ceiba L., Dalbergia sisoo Roxb., and others. Additionally, 74 shrub species from 28 families were identified across the study area, with an average species richness in moth habitats of S=23.31±5.34. Shrub species with higher density reported in this study included Melastoma malabathricum L., Triumfetta rhomboides Roxb., and others. Furthermore, the survey identified 87 herb species from 41 families across the study sites in the Cachar district. The average species richness of herb species in moth habitats was determined to be S=58.57±32.99. Herb species with higher density documented in Cachar district during the study included Polygonum microcephala (D. Don.) Sasaki, Cynodon dactylon (L.) Pers., and others. The study also highlighted food or host plants preferred by the Arctiidae, Geometridae, and Sphingidae moth families, belonging to various families such as Solanaceae, Moraceae, Poaceae, and others. This research significantly contributes to our understanding of the rich biodiversity of the Cachar district and the essential role played by plant species in supporting moth habitat.

Dynamic alterations in physiological and biochemical indicators of Cirrhinus mrigala hatchlings: A sublethal exposure of triclosan

Triclosan (TCS), a biocide used in various day-to-day products, has been associated with several toxic effects in aquatic organisms. In the present study, biochemical and hematological alterations were evaluated after 14 d (sublethal) exposure of tap water (control), acetone (solvent control), 5, 10, 20, and 50 μg/L (environmentally relevant concentrations) TCS to the embryos/hatchlings of Cirrhinus mrigala, a major freshwater carp distributed in tropic and sub-tropical areas of Asia. A concentration-dependent increase in the content of urea and protein carbonyl, while a decrease in the total protein, glucose, cholesterol, triglycerides, uric acid, and bilirubin was observed after the exposure. Hematological analysis revealed a decrease in the total erythrocyte count, hemoglobin, and partial pressure of oxygen, while there was an increase in the total leucocyte count, carbon dioxide, and partial pressure of carbon dioxide and serum electrolytes. Comet assay demonstrates a concentration-dependent increase in tail length, tail moment, olive tail moment, and percent tail DNA. An amino acid analyzer showed a TCS-dose-dependent increase in various amino acids. Sodium dodecyl sulphate polyacrylamide gel electrophoresis analysis revealed different proteins ranging from 6.5 to 200 kDa, demonstrating TCS-induced upregulation. Fourier transform infrared spectra analysis exhibited a decline in peak area percents with an increase in the concentration of TCS in water. Curve fitting of amide I (1,700–1600 cm−1) showed a decline in α-helix and turns and an increase in β-sheets. Nuclear magnetic resonance study also revealed concentration-dependent alterations in the metabolites after 14 d exposure. TCS caused alterations in the biomolecules and heamatological parameters of fish, raising the possibility that small amounts of TCS may change the species richness in natural aquatic habitats. In addition, consuming TCS-contaminated fish may have detrimental effects on human health. Consequently, there is a need for the proper utilisation and disposal of this hazardous compound in legitimate quantities.

Two decades of dune slack restoration in North Wales: diversity, community and habitat specialists

Humid dunes slacks are a highly threatened habitat, listed as vulnerable in the EU habitat red list. Accelerated successional processes in dune systems have resulted in the loss and degradation of ideal conditions for specialist dune slack species, hence the need for conservation management. We investigated the restoration of a dune slack in North Wales, UK, where vegetation and soil removal to 10 cm depth was undertaken to reinstate nutrient‐poor, open and damp conditions. We assessed the outcomes of the management for dune slack communities over the 18 years since restoration. We also assessed the differences between restored and unrestored areas of dune slacks. The dunes were restored in the winter of 2004/2005, after which we conducted vegetation surveys in fixed quadrats for most years in the restored and adjacent, un‐restored dune slacks. Species diversity and plant community composition changes over time were assessed using Shannon's index, multivariate analysis and indicator species analysis. Comparisons between the restored and unrestored areas of the dune slacks were also made. Ellenberg indicator values (EIVs) were examined to identify potential environmental drivers of post management successional changes. After 18 years the restored dune slacks developed a species‐rich and diverse community. compared to the unrestored slacks. The establishment of species occurred rapidly in the first three years, followed by continued but slower increases in species richness and diversity. This is due to the addition of new species without losses of established species. EIVs show no significant difference over time suggesting the restored areas are still at an early stage of succession. Distinct stages of community change since restoration are characterised by different indicator species. Plants are likely to be largely recruited from an existing seed bank. Restoration by turf removal may be suitable for other low nutrient, species rich habitats dependent upon fluctuating groundwater levels.

Plant species richness, not hygrothermal stress, is the main predictor of gall‐inducing insect richness in Peruvian Amazon forests

AbstractPatterns of gall‐inducing insect diversity tend to be influenced by both habitat‐related and plant‐related characteristics. We investigated the distribution patterns of galling insects in four vegetation types (terra firme forest, white‐sand dry forest, white‐sand wet forest and palm swamp forest) of the Peruvian Amazon to test if the insect gall diversity (1) differs among different types of vegetation and (2) depends on host plant richness. In total, we found 11,579 galls belonging to 249 insect gall morphotypes, distributed across 30 botanical families and 75 plant species. Among host plant families, Fabaceae showed the greatest richness of insect gall morphotypes. We found that galling species richness was lower in palm swamp forest than in white‐sand forests, which can be explained by the lower richness of plants in this type of vegetation. However, we found no evidence of greater richness in xeric habitats (e.g., white‐sand dry forest) than in more mesic vegetation (terra firme forest), contradicting the hypothesis of hygrothermal stress. We also found that plant species richness was positively influenced with the richness and abundance of galling species, regardless of vegetation type. Galling insect species composition differed significantly between vegetation types, similarly to the floristic composition. Our findings show that the diversity of galling insects in the tropical rainforests of Peruvian Amazon are mainly influenced by host plant composition and host plant richness.Abstract in Spanish is available with online material.

Contribution of military training areas for the conservation of calcareous grasslands

Calcareous grasslands are habitats of high conservation value. These rich habitats are declining notably due to agriculture and habitat fragmentation. In France, calcareous grasslands may be found on Military Training Areas (MTA), which protect them from intensive agriculture and urban development. By analysing their floristic structure and composition, the aim of this publication is to determine the conservation status of grassland on two French MTAs, following a gradient of intensity of military use called “militarisation gradient” in the rest of the publication. Vegetation characteristics appeared different according to the level of military activities. The level of military activity increases the average height of vegetation and the proportion of bare ground as well as the heterogeneity of the environment. Also, military activities and their related management, favour rich and diversified grasslands in a good conservation status, even if it could be improved by some adapted management methods. They also allow the creation of a mosaic of habitats within the grasslands with the presence of overgrown areas. Thus, MTAs appeared to present good potential for preserving of remaining calcareous grassland.

Living in the cracks: Two novel genera of Variosea (Amoebozoa) discovered on an urban sidewalk.

Biological soil crusts represent a rich habitat for diverse and complex eukaryotic microbial communities. A unique but extremely common habitat is the urban sidewalk and its cracks that collect detritus. While these habitats are ubiquitous across the globe, little to no work has been conducted to characterize protists found there. Amoeboid protists are major predators of bacteria and other microbial eukaryotes in these microhabitats and therefore play a substantial ecological role. From sidewalk crack soil crusts, we have isolated three naked amoebae with finely tapered subpseudopodia, and a simple life cycle consisting of a trophic amoeba and a cyst stage. Using a holistic approach including light, electron, and fluorescence microscopy as well as phylogenetics using the ribosomal small subunit rRNA gene and phylogenomics using 230 nuclear genes, we find that these amoeboid organisms fail to match any previously described eukaryote genus. However, we determined the amoebae belong to the amoebozoan lineage Variosea based on phylogenetics. The molecular analyses place our isolates in two novel genera forming a grade at the base of the variosean group Protosteliida. These three novel varioseans among two novel genera and species are herein named "Kanabo kenzan" and "Parakanabo toge."

The effect of habitat on benthic diatoms in subarctic ponds – differences between rock and sediment

Subarctic ecosystems represent a vulnerable environment for their biota and studying their habitats provides a better understanding of ongoing and accelerated environmental change. Literature suggests that habitat and environmental variables such as water chemistry jointly influence benthic algal species richness and assemblage composition. However, the combined effects of habitat and water chemistry on benthic algal communities are poorly understood especially in subarctic freshwaters. This study compared benthic diatom assemblages on rocks and on sediment and examined if environmental variables affect diatoms similarly in these habitats. A total of 20 subarctic ponds were sampled for diatoms on sediment and rock in summer 2022 in northern Fennoscandia. Differences in species richness and Pielou evenness between habitats were analysed by a paired Wilcoxon signed-rank test. The most significant environmental variables influencing diatom species richness were determined by generalized linear models. Differences in diatom assemblage compositions were analysed using non-metric multidimensional scaling, analysis of similarities, and Jaccard similarity index. Finally, to study how environmental variables shape diatom compositions on rock and sediment, a redundancy analysis was performed. According to our results species richness and evenness were significantly higher on sediment than on rock, and water pH was the major determinant for diatom richness in both habitats. Diatom assemblage composition did not differ between rocks and sediment, and composition was shaped by the same environmental variables such as pond surface area and water pH in both habitats. Our results support the prevailing conception that sediment habitat contains higher diatom species richness than rocks, while assemblage composition does not differ between these habitats. This study highlights the role of water pH on benthic diatoms regardless of their habitat. Given that global warming is expected to affect water pH levels, such a change will probably have a notable influence also on subarctic diatom communities in the future decades.

Spider diversity in different habitats at District Mardan, Khyber Pakhtunkhwa Pakistan.

Spider species are important for maintaining ecological balance, controlling insect populations, and providing potential sources of medicinal compounds. Highlighting the importance of spider species, the present study was aimed at exploring the diversity of spider fauna and species richness in various habitats in District Mardan, Khyber Pakhtunkhwa, Pakistan, from March 2021 to December 2021. Spiders were collected through different methods: pitfall traps, cryptic searching, ground hand collection, aerial hand collection, and vegetation beating. Then, the captured spiders were washed in alcohol and preserved in a combination of 80% alcohol and 20% glycerol for further observation. Identification was carried out with the help of available spider identification keys and literature. A total of 578 specimens representing 29 species from 17 families and 26 genera were collected and identified. Family Lycosidae was the most dominant family (13.49%), followed by Salticidae (10.2%), Araneidae (8.47%), Tetragnathidae (7.61%), Pholicidae (6.4%), Oxyopidae (5.88%), Thomisidae (5.7%), Clubionidae (5.53%), Sicariidae (5.19%), Scytodidae (5.01%), Corinnidae (4.67%), Agelenidae (4.32%), Cheiracanthiidae and Sparassidae (4.15%), Oecobiidae and Hersiliidae (3.97%) and Theridiidae was the rarest among all (1.21%). The most commonly identified species are Hippasa partita, Lycosa poonaesis, Lycosa terrestris, Draposa oakleyi, Plexippus paykulli, Menemerus nigli, Thyene imperialis, Thyene bivittate and Hasarius adansoni. Argiope versicolor, Neoscona theisi, Tetragnatha extensa, Crossopriza lyoni, and Oxyopes Javanus. During the present study, it was observed that spider species were abundantly found in warm areas from May to August, which demonstrates that the spider fauna of the study area is very rich but has yet to be explored.