Total Species Diversity Research Articles

Population genetic structure of Gymnospermium scipetarum subsp. eddae (Berberidaceae), an endangered Forest endemic from the Southern Apennines (Italy)

Assessing genetic diversity of narrow endemic plants is essential for their conservation. Gymnospermium scipetarum subsp. eddae (Berberidaceae) is an Italian endemic limited to a narrow forest area in the southern Apennines. Here we used random amplified polymorphic DNA (RAPD) markers to investigate population genetic differentiation and diversity in relation to distribution and microhabitat conditions. In all five extant populations and 134 individuals analysed we found a relatively low level of population genetic diversity (average Shannon-Weaver diversity index = 0.280; mean percentage of polymorphic bands = 57.45%; mean Nei’s gene diversity He = 0.187). Percentage of polymorphic bands (PPB) at species level was higher than at the population level (83.33%), while total species diversity (He = 0.210) was comparable to that found in the two southernmost subpopulations. AMOVA revealed a weak differentiation among populations, which shared three genetic pools in their genetic structure. The estimated gene flow among populations was relatively high (mean Nm = 5.320), while the Mantel test revealed no significant correlation between geographical and genetic distances at the population level. We argue that information on genetic diversity of G. eddae have important implications for conservation programmes, particularly for the establishment of ex-situ collections and restocking conservation actions.

The genetic diversity of the genus Mus (Linnaeus, 1758) in the eastern part of the North Caucasus

BackgroundThere are two species of Mus in the Caucasus: M. musculus and M. macedonicus. M. musculus is widespread in the Caucasus, where the species is found everywhere from the Black to the Caspian Sea. M. macedonicus is ubiquitous Transcaucasia. The most north-astern border of its distribution in the Caucasus, according to the literature, is located in the Derbent region, near the border between Dagestan and Azerbaijan.ResultsCytochrome b mt-DNA of genus Mus research in this study in the Eastern Caucasus. About 70% of M. musculus haplotypes from the lowlands of Dagestan were recorded for the first time. One of these haplotypes accounts for approximately 25% of the total species diversity of haplotypes. M. macedonicus was found in only one locality, the Sarykum barchans, where this species prevails in number and accounts for 70% of the total number mice of the genus Mus. The species is characterized by low values of genetic diversity and nucleotide variability, which may indicate that the population originated from a small number of founders and may explain its relative isolation from the main range. The dating of the appearance of the ancestors of M. musculus in the east of the Russian Caucasus corresponds to 99-66 thousand years ago (at a mutation rate of 3-10% per million years).ConclusionThe results obtained suggest that the history of the appearance of M. musculus in the Eastern Caucasus is more ancient and is not associated with human agricultural activities.We believe that possibly the ancestral range of M. musculus covered the eastern and western coasts of the Caspian Sea in the territory of southern Dagestan, Azerbaijan, and Iran. In this paper M. macedonicus, a Balkan-Asia Minor species, was registered for the first time in the North Caucasus. This species was registered in the center of Dagestan, where it inhabits sympatrically (on the territory) and syntopically (on the same biotope) with M. musculus. The low values of genetic diversity of M. macedonicus in the North Caucasus suggest that the population originated from a small group of founders.

The Level of Ecological and Hydrobiological Indicators in the Cheboksary Reservoir

The paper assesses the ecological state of the Cheboksary reservoir based on the criteria of the total abundance, biomass, and species diversity of phytoplankton, zooplankton, and benthos. During the study period, no significant changes in the indicators of the development of algocenoses, their distribution over the water area of the reservoir were noted. The average phytoplankton biomass for the reservoir turned out to be in the dynamic norm, the trophic status was assessed as eutrophic; The revealed ratios of the leading systematic groups of planktonic algae and the composition of cenosis-forming species had also been in the previous years of the study. According to the level of the saprobity index, all sampling stations belong to class III (moderately polluted waters). The benthos of the reservoir was also characterized by sufficient diversity with the dominance of mollusks and chironomid larvae in the taxonomic composition. Thus, despite the presence of a certain anthropogenic impact on the water area of the Cheboksary reservoir, its hydrobiological state remains satisfactory, which is determined by a wide buffer limit to the level of pollution of the water body.

Interactive effects of elevation and newly paved road on avian community composition in a scientific reserve, Bioko Island, Equatorial Guinea

AbstractUnderstanding interactive effects between anthropogenic disturbance and abiotic factors on species turnover can help to identify and prioritize conservation of potentially vulnerable tropical bird communities. We investigated the potential factors influencing avian understory community composition along with a recently constructed road across three elevations (300, 800, and 1200 m), each with two sampling sites (road edge vs. interior forest), over a four‐year period on Bioko Island, Equatorial Guinea. Insectivorous species were the most abundant guild‐sampled accounting for 55% of total species diversity within the dataset followed by frequent mixed‐flock followers (48%). Habitat associated with elevation was the most significant factor influencing the composition of avian communities. Additionally, we identified species with clear statistical associations for each elevation: the yellow‐lored bristlebill (Bleda notatus), olive sunbird (Cyanomitra obscura), and white‐tailed warbler (Poliolias lopezi). We found evidence for significant community differences between the disturbance edge and interior forest transects at 300 m only. Likewise, understory insectivores were found at higher numbers within the interior forest transect at this elevation. Based on the data presented here, we suggest low elevation avian understory insectivores should be considered focal species for future assessment studies in this area. Furthermore, since many traditional protected areas focus on upland habitat containing high species endemism, our findings emphasize the importance of equally conserving lowland elevations as they may house commonly overlooked, yet important and diverse segments of the bird community.Abstract in Spanish is available with online material.

Effects of rotation grazing time on the characteristics of soil seed bank in desert steppe.

Exploring the characteristics of soil seed bank under seasonal grazing plays an important role in the reasonable use of desert steppe. We examined seed bank species composition, density, vertical distribution, diversity in the soil of 0-5, 5-10, 10-15 cm soil layers and the relationship with vegetation and soil environmental factors in Ningxia desert steppe. The treatments included enclosure (FY), traditional time rotation grazing (FG), delayed to start rotation grazing (YG), early to end rotation grazing (TG), delayed to start and early to end rotation grazing (YT) and free grazing (ZY). The results showed that there were nine families and 21 species in the soil seed bank in the study area. The species composition of soil seed bank in TG seed bank with 13 species was the largest, while FY and ZY soil seed banks had the least, with 8 species, respectively. The den-sity of ZY soil seed bank was significantly higher than that of FY, YG, TG and YT. The number of perennial species seeds in the soil seed bank of FY was the largest, reaching 32.0%, while that in the ZY was the least, only 12.4%, mainly with sexually reproduced annual weeds. Soil seed bank was mainly concentrated in the 0-5 cm surface layer. With increasing soil depth, the size of soil seed bank decreased. The dominance and diversity of soil seed bank were the highest in FY, while the dominance, diversity and uniformity were the lowest in ZY. The similarity between soil seed bank and aboveground vegetation was generally low. In contrast, the FG and ZY seed banks had higher similarity with vegetation, and the FY was the lowest. Soil moisture, organic matter, total nitrogen concentration, total phosphorus concentration, and soil bulk density were the main soil factors affecting soil seed bank. Compared with traditional whole year free grazing, seasonal four-zone rotation grazing could increase species richness and abundance of perennial plants in soil seed bank of desert steppe, as well as the total species richness, diversity and uniformity of the seed bank. Although the effect sof seasonal four-zone rotation grazing on seed bank was not as good as the long-term enclosure grassland, it was of great significance to the utilization and protection of desert steppe.

Responses of mustelids and small mammal prey to combined retention on clearcuts: Woody debris, green trees, and riparian structures

Small mustelids such as the American marten (Martes americana) and short-tailed weasel (Mustela erminea) are important furbearers in temperate and boreal forests and are negatively affected by clearcutting. A major prey species, the southern red-backed vole (Myodes gapperi), also disappears from clearcuts and does not return to abundance levels of uncut forest for many decades. We tested the hypotheses (H) that on newly clearcut sites, (H1) the presence of small mustelids, (H2) abundance, species richness, and species diversity of the forest-floor small mammal community, and (H3) reproduction of the major species: M. gapperi and the deer mouse (Peromyscus maniculatus), would be greater on sites with combined retention treatments of woody debris piles, riparian, and green-tree retention than on sites with no retention. A fourth hypothesis (H4) predicted that the above response variables on sites with combined structural retention would be comparable to or higher than those in uncut old-growth forest. Mustelid presence and populations of forest-floor small mammals were sampled on five replicated (n = 4) treatment sites from 2017 to 2020 in south-central British Columbia, Canada.Mean presence (index of activity patterns) of mustelids was statistically similar among sites but in the combined treatments was 1.4 to 2.9 times higher than that in the dispersed (no retention) and uncut forest sites and was likely biologically important. Mustelid presence was particularly evident in the debris piles and riparian sites. Mean abundance of M. gapperi was 11.1 to 16.6 times higher in the combined retention and uncut forest sites than the dispersed sites. Mean abundance of P. maniculatus was higher in the dispersed than uncut forest, but similar in the combined retention to these treatments. Mean total abundance, species richness, and species diversity of eight small mammal species were all higher (1.3 to 1.6 times) in the combined retention sites than the dispersed and uncut forest sites. Although not formally significant (P = 0.08), results for mustelid presence tended to support H1 that these small carnivores would occur more frequently on sites with combined structural treatments than the dispersed and uncut forest sites. The overall high total numbers (and species richness and diversity) of small mammal prey species supported H2 that abundance would be greater on sites with the combined retention than on the dispersed sites with no retention. Reproduction and survival followed the pattern of abundance for the major species, and hence H3 was supported. Higher mean total abundance in combined retention sites than in uncut forest supported H4 in 2017–2018 but not in 2019–2020 when an influx of generalist species increased total abundance in the dispersed sites. This study is the first to measure the responses of small mustelids and small mammal prey species to combined structural retention. One or more of these retention treatments is highly recommended during most harvesting regimes in these forests.

Diversity of Cyanobacteria and Algae During Primary Succession in Iron Ore Tailing Dumps.

The extraction of commercial minerals is often accompanied by the formation of large areas of quarry and dump technogenic ecosystems. This stimulates the search for measures to reduce their negative impact on the environment, as well as a detailed study of all the constituent elements of ecosystems that spontaneously or after reclamation form on them. Primary stages of syngenesis on the tailing dumps of iron ore mines in Kryvorizhzhia took place involving cyanobacteria and eukaryotic algae. The dynamics of the community structures of algae and cyanobacteria depends on the mineralogical composition of tailings, salinity conditions, pH, and content of particles of physical clay and humus. The assessment of the features of the dynamics of algae communities was carried out based on the ordination procedure because of the method of non-metric multidimensional scaling. The considered environmental variables were statistically significant predictors of community structure and could explain 47-90% of the variation in measurements. Diagnostic signs of the species composition of communities of algae and cyanobacteria tailing dumps were established by physical and chemical parameters. An increase in the content of physical clay particles in the substrate and a pH shift towards the alkaline side increased the species richness of cyanobacteria, while an increase in the humus content increased the total species diversity. Based on the specificity of the type of growth and the species composition of algae communities, when describing the primary successions, it is proposed to allocate the following stages of development of algae and cyanobacteria communities: dispersal aerophyton, stratose epilitophyton, algal crust, mixed moss and algal crust, and edaphone.

Biodiversity consequences of Caulerpa prolifera takeover of a coastal lagoon

The genus Caulerpa has attracted much attention because many of its species were introduced into non-native regions and became notoriously invasive. This is the case of Caulerpa prolifera that has been rapidly expanding in Ria Formosa lagoon, taking over the deeper unvegetated soft bottoms and competing with seagrass meadows in the shallower areas. Here we address how C. prolifera invasion may affect the support of biodiversity, and specifically, the provision of habitat and nursery for commercial species by the native habitats of this coastal lagoon. Even though no significant differences in total species richness, diversity and evenness were found between C. prolifera and the native unvegetated habitat, the dissimilarity between these two habitats was highest, mostly driven by the extreme reduction of the gastropod Bittium reticulatum and of the tanaid Apseudopsis formosus. This may implicate changes in the trophic interactions of the ecosystem, for example decreasing the tanaid food source for seahorses, which are presently endangered in the lagoon. On the other hand, the fauna species richness, diversity and evenness were significantly higher in the native seagrass habitat than in C. prolifera. Juveniles of valuable flat and sparid fish were only observed in unvegetated sediments and seagrass meadows, respectively. The aggressive spread of C. prolifera in Ria Formosa may alter the structure of native faunal communities, with likely negative implications on fisheries. Nevertheless, the global biodiversity of the lagoon will not be likely drastically affected unless the seaweed takes over the seagrass meadows.

Acceleration of Forest Structural Development for Large Trees and Mammals: Restoration in Decades or Centuries?

There is a demand for more progressive restoration directives to regenerate forest ecosystems impacted by harvesting, wildfire, insect outbreaks, and mineral resource extraction. Forest restoration may take many decades and even centuries without active silvicultural intervention to grow large trees that provide suitable habitat for various wildlife species. We tested the hypotheses (H) that, compared with unmanaged (unthinned and old-growth) stands, large-scale precommercial thinning (heavy thinning to <500 stems/ha) of young lodgepole pine (Pinus contorta var. latifolia), at 20–25 years post-treatment, would enhance: (H1) the architecture of large overstory trees (e.g., diameter, height, and crown dimensions); (H2) mean (i) total abundance and species diversity of forest-floor small mammals, (ii) abundance of tree squirrels; and (H3) relative habitat use by mule deer (Odocoileus hemionus). There were three levels of thinning with mean densities of crop trees/ha: 353 (low), 712 (medium) and 1288 (high), an unthinned, and old-growth stand replicated at three areas in south-central British Columbia, Canada. Mammal abundance and habitat use were measured during the period 2013 to 2015. Mean diameter of crop trees was significantly different among stands with the low-density, medium-density, and old-growth stands having diameters larger than the high-density and unthinned stands. Mean height of crop trees was highest in the old-growth stands. Mean crown volume of crop trees was significantly different among stands with the low-density stands 2.1 to 5.8 times higher than the high-density, unthinned, and old-growth stands, and hence partial support for H1. Mean total abundance of forest-floor small mammals was significantly different among stands with the low-density and old-growth stands 1.9 to 2.4 times higher than the other three treatment stands. Mean abundances per stand of the red squirrel (Tamiasciurus hudsonicus) (range of 4.8 to 12.0) and the northern flying squirrel (Glaucomys sabrinus) (range of 3.2 to 4.3) were similar among stands. Mean relative habitat use by mule deer was similar among stands, but variable with counts of pellet-groups/ha in the thinned stands were 3.8 to 4.2 and 2.1 to 2.3 times higher than the unthinned and old-growth stands, respectively. Thus, mean total abundance of forest-floor small mammals of H2 was supported, but species diversity and abundance of tree squirrels was not. Enhanced relative habitat use by mule deer (H3) was not supported. To our knowledge, this is the first concurrent measurement of several mammal species in heavily thinned, unthinned, and old-growth forest across three replicate study areas at 20–25 years post-treatment. Although not all mammal responses were significant, there was a strong indication that restored forests via heavy thinning (<500 trees/ha) produced large overstory trees (at least for diameter and crown dimensions) in stands 33 to 42 years old. Comparable old-growth stands, albeit with crop trees of greater height and merchantable volume, ranged from 120 to 167 years of age. Restored forests with large trees capable of supporting at least these mammal species may be achieved in decades rather than centuries.

Taxonomic structure of the flora of Male Opillya

The article provides information on the flora of Male Opillya, the southwesternmost part of the Opillya area, Western Ukraine. The ecological and geographical peculiarities of the area determine its rich plant diversity. The flora of Male Opillya comprises 1325 species of vascular plants belonging to 511 genera, 95 families and five divisions. A characteristic feature of the flora of this area is a small number of vascular cryptogamic plants and gymnosperms – 27 species, or 2.04% of the total number of species of vascular plants. The division Magnoliophyta consists of 1298 species (97.96%), of them Liliopsida accounts for 21.21% and Magnoliopsida – 76.75%. Taxonomic diversity of the flora is characterized by the following proportions: mean number of species per family is 13.95, mean number of genera per family – 5.38, mean number of species per genus – 2.59. The ten leading families by number of taxa contain together 757 species (57% of the total number) and 134 genera. Among them, the best represented families are Asteraceae (193, or 25.5%), Poaceae (105, or 13.87%), and Rosaceae (71, or 9.38%). The ten largest genera by number of species (from 51 to 14 species in each), comprise 204 species, or 15.4% of the total species diversity. Of them, the following genera contain the highest number of species: Carex (51 species), Hieracium (25), and Veronica (23). The genera represented by a single species make up more than half of all genera of the flora (277, or 54.21%).

Ecological indicators and bioindicator plant species for biomonitoring industrial pollution: Eco-based environmental assessment

Industrial pollution remains a driving force to ecosystem alteration. Pollutants are released in the atmosphere interacting in turn with other components of earth system such as plant species. Despite the long-term exposition of vegetation cover to pollution is drastically devastating, less is known about the contribution of ecological indicators for its monitoring. The aims of this study are (i) to introduce the ecological indicators in assessing the cement dust impact on plant species and its biomonitoring and (ii) to screen new indicator species for phytoremediation studies. Floristic surveys were conducted in the cement plant closeness following quadrat method. Vegetation indicators such as total plant cover, perennial and annual species densities and diversity were assessed. Bioindicator species were identified using the bioaccumulation factor (BF) and translocation factor (TF). A decrease of perennial species richness and a decline of total vegetation cover by 7 times as well as a diversity decrease ranging from 2.99 to 2.31 were found pertinent indicators of land degradation in the industrial area. Annual species densities were significantly affected by cement pollution. Species like Lygeum spartum, Atractylis serratuloides and Gymnocarpos decander arise as indicators of heavy metals pollution. Pollution in the cement plant vicinity excluded sensitive species like Helianthemum kahiricum, Stipa tenassissima, Plantago coronopus. This study allowed the identification of indicator species of potential use in phytoremediation applications and emphasized the possibility of relaying on the vegetation indicators to assess the impact of cement pollution.

Strong macrobenthic community differentiation among sub-Arctic deep fjords on small spatial scales

Fjords play an important role in carbon cycling and sequestration, but the burial of organic matter in sediments strongly depends on the composition of macrobenthic communities. We studied three deep, sub-Arctic fjords located in northern Norway to assess the community differentiation of neighbouring fjords and the underlying environmental drivers. The fjords have relatively deep depositional basins (370–570 m), but they differ in sill depth and water exchange. In all fjords studied, the silty sediments were characterised by organic matter of mostly marine origin. We found that each basin was inhabited by a distinct benthic community, with pronounced differences in total abundance, biomass and species diversity. Only in one fjord (Skjerstadfjord), with a shallow sill, a slight mouth-to-head pattern of the community was found. The strong differentiation of macrobenthos among different fjords seems not to be directly associated with environmental drivers such as organic matter input, water masses or depth.

Structure and Diversity of the Demersal Fish Assemblages off Psara Island (Central Aegean Sea) Caught by Experimental Bottom Trawling

Data with high spatial resolution on the structure and diversity of marine assemblages are valuable for fisheries management and conservation planning but are seldom available. This study provides fisheries-independent, baseline information on the structure and diversity of the demersal fish assemblages of the continental shelf and upper slope off the island of Psara (Central Aegean Sea). Experimental bottom trawl hauls were conducted during 2009–2010, using identically designed trawls. All the fish in the catches were identified onboard, enumerated, and weighted to the nearest g. Species abundance and biomass were transformed to CPUE. Forty-seven taxa were identified in the catches. For 18 of the species caught no other fisheries-independent information on their abundances and distributions is available for the wider area. Among the Elasmobranchii species collected, Squalus acanthias, Dipturus oxyrinchus, and Raja clavata are species of conservation concern. Species composition was generally more similar to that reported for assemblages of the Cretan Sea and the South Aegean Sea than for assemblages of the North Aegean. The assemblages were structured with depth, a pattern that may be driven in part by the differences in benthic habitat between depth zones. No trends by depth in total numerical abundance and species diversity were identified, whereas the bathymetric change in taxonomic diversity was attributed to the depth distributions of certain species-rich orders and families. The frequency distribution of the trophic level of the species followed the broad-scale pattern that applies in the Mediterranean Sea.

Biodiversity of free-living ciliates of the Kura River basin (within Azerbaijan)

As a result of long therm free-living ciliates investigation of the Kura River basin, in all 308 species have been noted. The article provides information on the ciliates species diversity of 8 sample points, across the Kura River within Azerbaijan – from Georgian state border to the delta. The freshwater ciliates species diversity varies considerably depending on location and environment sample points. The greatest diversity of freshwater ciliates noted in Mingechevir and Varvara reservoirs (128 and 140 species respectively), which in our opinion, is related with a variety of biotopes in these reservoirs and an abundance of food organisms. The analysis on the occurrence of ciliates showed that the group of dominants (noted in more than 80 % of all samples) includes 10.71 % of the total species diversity, and the group of regular ones (occurrence less than 80, but more than 50 %) 13.60 % of the entire species composition, 71.47 % belong to the largest group of irregular ones (occurrence from 30 to 50 % in samples), and 4.22 % of the total species diversity to the group of random species (occurrence less than 30 % of all samples). It has been established that the largest group of irregular species is consist ciliates, confined to a certain time of the year – mainly in spring and fall. At the same time, part of this group species appeared in the communities only in the summer.

Effects of landscape composition and site land-use intensity on secondary succession in a tropical dry forest

Regenerating forests after agricultural land abandonment are increasingly common in human-modified tropical landscapes. These secondary forests preserve biodiversity and provide multiple ecosystem services, but such important roles depend on their recovery rates, which can be difficult to predict. Recovery is expected to occur faster when landscape composition favors seed dispersal to the regenerating site, and when previous land-use does not significantly reduce propagule bank or future plant growth. Here, we test such expectations for the recovery of a Mexican tropical dry forest during secondary succession. For this purpose, we measured several indicators of landscape composition and site land-use intensity in 30 regenerating sites located along gradients of age of abandonment and amount of surrounding forest. Generalized linear models and redundancy analysis were fitted to test if values of four vegetation properties (aboveground biomass, total and dominant species diversity, and species composition) were indicative of such effects. We found evidence that, as expected, species richness recovers faster in sites surrounded by higher forest cover, while aboveground biomass recovers slower as surrounding pasture cover increases. Species composition was also significantly but poorly explained by the interaction between age of abandonment and the amount of forest cover. Contrary to our expectations, we found weak evidence on the impact of site land-use intensity on all vegetation properties, except on the number of dominant species, which showed higher values in sites with higher land-use intensity. Our findings show that landscape context plays a major role in structuring successional plant communities in this tropical dry region, even stronger than site land-use intensity. This seems to be related to the influence of landscape patterns on dispersal and recruitment limitation, but also on the likelihood of further human disturbances. Therefore, conserving landscape quality is paramount to enhance forest recovery and its contribution to the preservation of biodiversity and ecosystem services.

Understory vegetation dynamics of Chinese fir plantations and natural secondary forests in subtropical China

Understory vegetation is a vital component of forest ecosystems and contributes to terrestrial plant diversity, nutrient cycling and energy flows. Plantations and natural secondary forests are two dominant types that emerge following stand-replacing disturbances in managed landscapes. However, to date, the long-term dynamics of the cover, diversity, and composition of understory vegetation in plantations and secondary forests remain poorly understood. We sampled understory vegetation of Chinese fir plantations and natural secondary forests with their ages spanning 4 to 40 years and used primary forests as a reference in subtropical China. The cover and species diversity of the shrub layer were significantly higher in the natural secondary forests than in Chinese fir plantations in two younger age classes, but they converged in older stands. In the herb layer, Chinese fir plantations possessed a higher total and vascular species diversity across all age classes, but their covers did not differ significantly between the two forest types, except for a higher cover of vascular plants in the 8–12-year-old Chinese fir plantations. The bryophyte cover did not differ with forest type nor stand age, while bryophyte species diversity was significantly higher in Chinese fir plantations. The cover and species diversity of understory vegetation in the primary forests were similar to those in the 35–40-year-old natural secondary forests. Across all forest types and age classes, the cover and diversity were positively correlated within each plant group, and the shrub cover and diversity were negatively correlated with vascular diversity in the herb layer, but neither the cover nor the diversity of bryophytes was correlated with those of the shrub layer or herb layer. Species composition differed significantly with forest type and stand age. Natural secondary forests had more similar understory species composition to primary forests than Chinese fir plantations did. Our results suggest that forest management may increase the diversity of the herb layer, but at the expense of the abundance and diversity of the shrub layer. The shrub layer may not regenerate, or its regeneration will be slow due to exhausted seed and propagulum banks after multiple management rotations. Moreover, the high cover of the shade-intolerant and nutrient-demanding herbaceous plants in Chinese fir plantations may have adverse effects on ecosystem service functions.

The importance of assessing positive and beneficial impacts of alien species

Extensive literature is available on the diversity and magnitude of impacts that alien species cause on recipient systems. Alien species may decrease or increase attributes of ecosystems (e.g. total biomass or species diversity), thus causing negative and positive environmental impacts. Alien species may also negatively or positively impact attributes linked to local human communities (e.g. the number of people involved in a given activity). Ethical and societal values contribute to define these environmental and socio-economic impacts as deleterious or beneficial. Whilst most of the literature focuses on the deleterious effects of alien taxa, some recognise their beneficial impacts on ecosystems and human activities. Impact assessment frameworks show a similar tendency to evaluate mainly deleterious impacts: only relatively few, and not widely applied, frameworks incorporate the beneficial impacts of alien species. Here, we provide a summary of the frameworks assessing beneficial impacts and briefly discuss why they might have been less frequently cited and applied than frameworks assessing exclusively deleterious impacts. Then, we review arguments that invoke a greater consideration of positive and beneficial impacts caused by alien species across the invasion science literature. We collate and describe arguments from a set of 47 papers, grouping them in two categories (value-free and value-laden), which span from a theoretical, basic science perspective to an applied science perspective. We also provide example cases associated with each argument. We advocate that the development of transparent and evidence-based frameworks assessing positive and beneficial impacts might advance our scientific understanding of impact dynamics and better inform management and prioritisation decisions. We also advise that this development should be achieved by recognising the underlying ethical and societal values of the frameworks and their intrinsic limitations. The evaluation of positive and beneficial impacts through impact assessment frameworks should not be seen as an attempt to outweigh or to discount deleterious impacts of alien taxa but rather as an opportunity to provide additional information for scientists, managers and policymakers.

Impact of Urbanisation and Human Activities on Diversity and Abundance of Ulidiid Flies (Diptera: Ulidiidae) in Wadi El-Natroun, Egypt

Urbanisation and its effects is one of the biggest and most critical environmental issues facing the world. In the present study, we evaluate the impact of urbanisation on the picture-winged flies (family Ulidiidae) communities in Wadi El-Natroun Depression, by assessing the changes in abundance and diversity. Six sites, each measuring about 2.1 ha, were determined: three sites (A1, A2, A3) are in an open area out of the city, and three sites (B1, B2, B3) are on the periphery of the city surrounded by inhabited buildings and assumed to suffer from anthropogenic activities (urbanised sites). The fly sampling was conducted monthly from January to December 2015 using sweep nets. Total abundance and species diversity of ulidiids in open sites were significantly higher than in urbanised sites. A similar population trend was recorded for Physiphora alceae (Preyssler) and Physiphora smaragdina (Loew). These species appear in early spring and increase gradually but were almost eliminated by the beginning of the fall. A bimodal seasonal profile was observed with two peaks of Ulidia fascialis Hendel density: April and July. The correlation between species abundance and temperature was positive, but it was only significant with P. alceae in the urbanised area and with P. smaragdina in the open area. In contrast, an inverse correlation was recorded between species abundance and relative humidity; however, it was only significant with P. alceae in open and urbanised areas. A scatter plot generated from a principal component analysis (PCA) of species abundance showed a clear grouping of the study sites based on whether they were open or urbanised. The results of the present study showed that the picture-winged flies were directly affected by the habitat changes related to urbanisation. Both species abundance and diversity were dramatically reduced in the urbanised area. Consequently, these flies could be potential habitat quality indicators.

Increasing confidence for discerning species and population compositions from metabarcoding assays of environmental samples: case studies of fishes in the Laurentian Great Lakes and Wabash River

Community composition data are essential for conservation management, facilitating identification of rare native and invasive species, along with abundant ones. However, traditional capture-based morphological surveys require considerable taxonomic expertise, are time consuming and expensive, can kill rare taxa and damage habitats, and often are prone to false negatives. Alternatively, metabarcoding assays can be used to assess the genetic identity and compositions of entire communities from environmental samples, comprising a more sensitive, less damaging, and relatively time- and cost-efficient approach. However, there is a trade-off between the stringency of bioinformatic filtering needed to remove false positives and the potential for false negatives. The present investigation thus evaluated use of four mitochondrial (mt) DNA metabarcoding assays and a customized bioinformatic Bioinformatic pipeline to increase confidence in species identifications by removing false positives, while achieving high detection probability. Positive controls were used to calculate sequencing error, and results that fell below those cutoff values were removed, unless found with multiple assays. The performance of this approach was tested to discern and identify North American freshwater fishes using lab experiments (mock communities and aquarium experiments) and processing of a bulk ichthyoplankton sample. The method then was applied to field environmental (e) DNA water samples taken concomitant with electrofishing surveys and morphological identifications. This protocol detected 100% of species present in concomitant electrofishing surveys in the Wabash River and an additional 21 that were absent from traditional sampling. Using single 1 L water samples collected from just four locations, the metabarcoding assays discerned 73% of the total fish species that were discerned during four months of an extensive electrofishing river survey in the Maumee River, along with an additional nine species. In both rivers, total fish species diversity was best resolved when all four metabarcoding assays were used together, which identified 35 additional species missed by electrofishing. Ecological distinction and diversity levels among the fish communities also were better resolved with the metabarcoding assays than with morphological sampling and identifications, especially using all four assays together. At the population-level, metabarcoding analyses targeting the invasive round goby Neogobius melanostomus and the silver carp Hypophthalmichthys molitrix identified all population haplotype variants found using Sanger sequencing of morphologically sampled fish, along with additional intra-specific diversity, meriting further investigation. Overall findings demonstrated that the use of multiple metabarcoding assays and custom bioinformatics that filter potential error from true positive detections improves confidence in evaluating biodiversity.

The Peculiarities of the Shikhan Faunas and Communities of Phytophagous Beetles (Coleoptera: Chrysomeloidea, Curculionoidea) near the Town of Sterlitamak, the Republic of Bashkortostan

The species composition and the general characteristics of the fauna of phytophagous beetles (superfamilies Chrysomeloidea and Curculionoidea) on the Sterlitamak shikhans are considered based on original material. The shikhans Tratau, Kushtau, and Yuraktau are cone-shaped relict limestone mountains that are unique natural objects located near Sterlitamak in the Republic of Bashkortostan. The shikhans reveal an extremely high total species diversity of leaf beetles and weevils, comprising 327 species from 8 families, or no less than 25% of the entire faunas of these groups in the forest-steppe belt of the Volga Region and the Cis-Urals. Of the three shikhans, the fauna of Tratau with 283 species is the richest and the most specific. Among the zonal complexes, the group of phytophagous beetles of steppe ecosystems is the most diverse on the shikhans, comprising 297 species, or 90% of the species recorded. The arealogical and ecological analyses have shown that the shikhan faunas have a fairly original structure characterized by pronounced participation of both Western and Central Palaearctic species, many of which are located there at the meridional limits or within the insular parts of their ranges. The studied faunas have a large proportion of petrophilic steppe and desert-steppe forms and include many relict faunal elements of different origins. Most of the relicts are concentrated in petrophytic steppes, screes, and rock outcrops of the shikhans, some of them being trophically associated with relict and/or endemic plant species. Stephanocleonus ignobilis, Pseudocleonus dauricus, and Ceutorhynchus subpilosus are known in Bashkortostan only from the shikhans; it is suggested that these relict species should be included in the regional Red Data Book. In addition, two apparently flightless and probably new species of flea beetles from the genera Phyllotrera Chevr. and Longitarsus Berth. were found on Tratau. The forest ecosystems contain a sufficiently rich group of nemoral species associated with the European oak; these species occur in Bashkortostan at or near their eastern range limits. The data presented clearly show that the fauna and communities of phytophagous beetles of the Sterlitamak shikhans are highly original, reflecting the uniqueness of their natural complexes as a whole and providing a very important argument against industrial development of any of the shikhans.