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This study conducted from January to June 2018, attempts to determine the density, habitat preferences and attitudes of people towards Gekko gecko and its impact on the conservation of this species in human-dominated landscapes in Sonitpur district, Assam. Eight villages at different distances from Nameri Tiger Reserve were chosen for the study. The line transects analyzed using DISTANCE software estimated a density of 7.99 individuals ha−1 in fringe villages of Nameri Tiger Reserve which also had higher number of host tree species diversity with higher basal area and density as compared to that of villages distant from Nameri Tiger Reserve. Gekko gecko was sighted on a total of 30 trees (6 species, 2 families), the highest being Ficus rumphii (40%). Maximum sightings of Gekko gecko was done on trees (67%). The occurrence of Gekko gecko was highly influenced by distance from forest (12%), followed by source of income (11%) and gender (4%). The majority of the respondents (53.54%) revealed that Gekko gecko occurred naturally in the homegardens implying that homegardens provided the habitat that can support the populations of Gekko gecko. But 46.45% of the respondents reported that they were adopted (62.16% in villages distant from Nameri Tiger Reserve), which raises serious concerns about the conservation of Gekko gecko in homegardens. Though, majority of the people knew that it is illegal to trade Gekko gecko, the financial benefits of its trade is very alluring. To make homegardens more favourable for the survival of Gekko gecko there should be strict law enforcement, upgradation of the species in the IUCN Red List and options for alternative livelihood.

The widespread of invasive plants across the world has increased the risk of extinction of native plants. It is then necessary for understanding the ecological impacts of invasive plants on neighbouring plant communities where they are found. This study aimed to assess the impacts of the abundance of Pneumatopteris afra on plant diversity of some invaded wetlands in Lafia, Nigeria. Three wetlands with size 500 × 500 m2 each were chosen. Forty 1.5 m × 1.5 m quadrats were laid at 10 m intervals across four 200 m transects at each wetland. The abundance of each plant species within the quadrats was counted and was used to estimate the diversity indices. The impact of the abundance of P. afra on the wetland communities was determined using Pearson correlation coefficients and linear regression models. A total of nine neighbouring plant species including P. afra were identified in all the sites. P. afra has the highest relative frequency and abundance in all the sites. Shannon and Simpson's diversity indices of all the sites are less than 2 showing that they are less diverse. The abundance of P. afra exhibited negative relationships with the diversity indices. Regression models also showed inverse relationships between P. afra and the diversity indices. The colonization of these wetlands by P. afra might be due to its ability to maximize disturbances and limit the growth and expansion of surrounding plants.

Identification of nest predators and anti-predator behavior of Vanellus indicus (red wattled lapwings) were studied during two constitutive breeding periods (March-August) of 2018 and 2019. The study was performed along the river Ganges, Raebareli (Uttar Pradesh), India. The number of nesting pairs was counted by the line transect method and anti-predator responses were recorded by the focal sampling method. The nesting pairs varied significantly within and between study sites and years. A variety of predators (avian, mammalian and reptilian) were identified while some predators were designated in the unknown category. Sitting tight response was significantly different during the incubation period. The mobbing response, flying away and running away responses were significantly different during the post-incubation period. Circle noisily over the nests and alarm call were not significant between the two reproductive stages. We conclude that red wattled lapwings can differentiate among diverse predator species and adopt various anti-predator responses against them at different stages of their breeding cycle.

Continental shelves are thought to be affected disproportionately by climate change and are a large contributor to global air–sea carbon dioxide (CO2) fluxes. It is often reported that low-latitude shelves tend to act as net sources of CO2, whereas mid- and high-latitude shelves act as net sinks. Here, we combine a high-resolution regional model with surface water time series and repeat transect observations from the Scotian Shelf, a mid-latitude region in the northwest North Atlantic, to determine what processes are driving the temporal and spatial variability of partial pressure of CO2 (pCO2) on a seasonal scale. In contrast to the global trend, the Scotian Shelf acts as a net source. Surface pCO2 undergoes a strong seasonal cycle with an amplitude of ∼ 200–250 µatm. These changes are associated with both a strong biological drawdown of dissolved inorganic carbon (DIC) in spring (corresponding to a decrease in pCO2 of 100–200 µatm) and pronounced effects of temperature, which ranges from 0 ∘C in the winter to near 20 ∘C in the summer, resulting in an increase in pCO2 of ∼ 200–250 µatm. Throughout the summer, events with low surface water pCO2 occur associated with coastal upwelling. This effect of upwelling on pCO2 is also in contrast to the general assumption that upwelling increases surface pCO2 by delivering DIC-enriched water to the surface. Aside from these localized events, pCO2 is relatively uniform across the shelf. Our model agrees with regional observations, reproduces seasonal patterns of pCO2, and simulates annual outgassing of CO2 from the ocean of +1.7±0.2 mol C m−2 yr−1 for the Scotian Shelf, net uptake of CO2 by the ocean of -0.5±0.2 mol C m−2 yr−1 for the Gulf of Maine, and uptake by the ocean of -1.3±0.3 mol C m−2 yr−1 for the Grand Banks.

Elevational patterns of tree diversity are well studied worldwide. However, few studies have examined how seedlings respond to elevational gradients and whether their responses vary across climatic zones. In this study, we established three elevational transects in tropical, subtropical and subalpine mountain forests in Yunnan Province, southern China, to examine the responses of tree species and their seedlings to elevational gradients. Within each transect, we calculated species diversity indices and composition of both adult trees and seedlings at different elevations. For both adult trees and seedlings, we found that species diversity decreased with increasing elevation in both tropical and subalpine transects. Species composition showed significant elevational separation within all three transects. Many species had specific elevational preferences, but abundant tree species that occurred at specific elevations tended to have very limited recruitment in the understory. Our results highlight that the major factors that determine elevational distributions of tree species vary across climatic zones. Specifically, we found that the contribution of air temperature to tree species composition increased from tropical to subalpine transects, whereas the contribution of soil moisture decreased across these transects., Highlights • Species richness and diversity decreased with increasing elevation in tropical and subalpine transects. • Species similarity between adult trees and seedlings decreased with increasing elevation in the tropical transect. • Species similarity between adult trees and seedlings increased with increasing elevation in the subalpine transect. • Effect of temperature on species distribution increased from tropical to subalpine zones. • The effect of soil moisture on species distribution decreased from tropical to subalpine zones. • Abundant tree species at each elevation often had very limited seedlings.

Understanding how terrestrial biotic communities have responded to glacial recession since the Last Glacial Maximum (LGM) can inform present and future responses of biota to climate change. In Antarctica, the Transantarctic Mountains (TAM) have experienced massive environmental changes associated with glacial retreat since the LGM, yet we have few clues as to how its soil invertebrate-dominated animal communities have responded. Here, we surveyed soil invertebrate fauna from above and below proposed LGM elevations along transects located at 12 features across the Shackleton Glacier region. Our transects captured gradients of surface ages possibly up to 4.5 million years and the soils have been free from human disturbance for their entire history. Our data support the hypothesis that soils exposed during the LGM are now less suitable habitats for invertebrates than those that have been exposed by deglaciation following the LGM. Our results show that faunal abundance, community composition, and diversity were all strongly affected by climate-driven changes since the LGM. Soils more recently exposed by the glacial recession (as indicated by distances from present ice surfaces) had higher faunal abundances and species richness than older exposed soils. Higher abundances of the dominant nematode Scottnema were found in older exposed soils, while Eudorylaimus, Plectus, tardigrades, and rotifers preferentially occurred in more recently exposed soils. Approximately 30% of the soils from which invertebrates could be extracted had only Scottnema, and these single-taxon communities occurred more frequently in soils exposed for longer periods of time. Our structural equation modeling of abiotic drivers highlighted soil salinity as a key mediator of Scottnema responses to soil exposure age. These changes in soil habitat suitability and biotic communities since the LGM indicate that Antarctic terrestrial biodiversity throughout the TAM will be highly altered by climate warming.

The Kettara abandoned mine, Morocco, is a highly acid drainage-generating site with negative impacts. In order to impede the water–oxygen migration within tailings of Kettara mine, a store-and-release (SR) cover made with phosphate mine wastes (PMW) layers was implemented on the tailings of Kettara mine in five experimental cells. The characterization of vegetation is an important aspect of the monitoring strategy for the SR cover. In this optic, the objective of this study was to follow the local flora dynamic on the SR cover. Furthermore, this research highlighted the potential of this flora for the development of other appropriate phytomanagement plans of mining wastes. The monitoring surveys were carried out over five years (March 2015–April 2019). Six permanent transects were placed on five-constructed cells. The method of Line Intercept Transect was used to evaluate the vegetation cover and to determinate the floristic composition and relative frequency of the species. Plant diversity was quantified by Shannon diversity (H′) and Pielou evenness (J') indices. Four functional groups of plants were identified; therophytes and chamaephytes were the most abundant. Among 19 recorded families on SR cover, the most widely represented were Compositae (26.83%), Leguminosae and Poaceae with 9.76%, Apiaceae and Brassicaceae with 7.32% of the total taxa for each one of them. Of the 39 identified vascular species on SR cover, the most abundant were Anacyclus valentinus L., Calendula arvensis M.Bieb., Emex spinosa (L.) Campd., Hirschfeldia incana (L.) Lagr.-Foss., Spergularia rubra (L.) J.Presl & C.Presl, Stipa capensisthunb, and Herniaria cinerea L. Significant differences in Shannon diversity index (H′) were observed between the sampling areas (p > 0.05), it ranged from 0.739 to 3.857 bits/ind. on SR cover. The Pielou evenness index was not significantly different through transects; it varied from 0.578 to 0.978. These values indicated an equitable distribution of individuals within species on the investigated transects. The study revealed 29 vascular plant species that represent a great potential to be promoted for the phytomanagement of mine wastes in the context of arid and semi-arid environments.

The larval stage of invasive Dreissena spp. mussels (i.e., veligers) are understudied despite their seasonal numerical dominance among plankton. We report the spring and summer veliger densities and size structure across the main basin, North Channel, and Georgian Bay of Lake Huron, and seek to explain spatiotemporal variation. Monthly sampling was conducted at 9 transects and up to 3 sites per transect from spring through summer 2017. Veliger densities peaked in June and July, and we found comparable densities and biomasses of veligers between basins, despite differences in density of juvenile and adult mussels across these regions. Using a generalized additive model to explain variations in veliger density, we found that temperature, chlorophyll a, and nitrates/nitrites were most important. We generated an index of veliger attrition based on size distributions that revealed a higher rate of attrition in the North Channel than the rest of the lake. A logistic model indicated a threshold calcium concentration of around 22 mg/L was necessary for veligers to survive to larger sizes and recruit to their juvenile and benthic adult life stages. Improved understanding of factors that regulate the production and survival of Dreissena veligers could improve the ability of managers to assess future invasion threats as well as explore potential control options.

Gold in the Abitibi greenstone belt in the Superior craton, the most prolific gold-producing greenstone terrane in the world, comes largely from complex orogenic mineralizing systems related to deep crustal deformation zones. In order to get a better understanding of these systems, we therefore combined new magnetic, gravity, seismic, and magnetotelluric data with stratigraphic and structural observations along a transect in the Matheson area of the Abitibi greenstone belt to constrain large-scale geologic models of the Archean crust. A high-resolution seismic transect reveals that the well-known Porcupine Destor fault dips shallowly to the south, whereas the Pipestone fault dips steeply to the north. Facing directions and gravity models indicate that these faults are thrust faults where older mafic volcanic rocks overlie a younger sedimentary basin. The depth of the basin reaches ~2 to 2.5 km between these two faults, where it is interpreted to overlie mafic-dominated volcanic substrata. Regional seismic and magnetotelluric surveys image the full crust down to 36-km depth to reveal a heterogeneous architecture. Three crustal-scale layers include a resistive (104–105 Ωm) upper crust of granite-greenstone rocks, a low-resistivity (~10–50 Ωm) middle crust dominated by granitic plutons for which low resistivity is attributed to the presence of graphite, and a low to moderately resistive (50–1,000 Ωm) and seismically homogeneous lower crust interpreted as granulite gneisses. The significant resistivity transition between upper and middle crust is interpreted to be the result of interconnected micrographite grain coating, precipitated from carbon-bearing crustal fluids emplaced during Neoarchean craton stabilization. A major subvertical, seismically transparent, and extremely low resistive (

Monitoring waterbird populations in Australia is challenging for reasons of counting logistics, and because population aggregation and dispersion can shift rapidly in response to large spatio-temporal variations in resource availability. The East Australian Waterbird survey has conducted annual, aerial, systematic counts of waterbirds over eastern Australia for almost 40 years. It was designed to monitor waterbird populations using design-based inference though for many species this form of inference appears inadequate in the face of these challenges. Here we develop a state-space model-based Bayesian approach that, in addition to explicitly incorporating process noise and observation uncertainty, uses random effects and rainfall-derived covariates to model the year-to-year variation in the proportion of the total (super) population that is present on surveyed wetlands, and available to be counted. We use this model-based approach to estimate the superpopulation size of 45 waterbird species annually, and model the rate of population increase as a function of antecedent rainfall. The results confirm the strong positive effect of antecedent rainfall on population growth rates for nearly all species, and illustrate that species respond to rainfall differently in terms of habitat use, which influences whether they are present on surveyed wetlands. For many species, the year-to-year variation in the estimated proportion of the population on surveyed wetlands is very high. The results have implications for making inferences on population trends from these data, with the ability to model the year-to-year sampling variation a key requirement before the rate of population increase can be estimated with any precision. This study illustrates how to progress this approach, and infers that under average rainfall conditions, the general trend is for estimated superpopulation rates of increase to be negative, though for only a few species is this occurring with strong belief.

To understand rural sustainability, it is necessary to scrutinize the relationship between rural transition and economic growth. The article uses rural multifunctionality as an analytical lens through which to view the processes of the development of rural occupancy. There is a pressing need to ascertain how to quantify rural multifunctionality and reveal its spatial differentiation, as well as garner and investigate how multifunctional rural transition (MRT) responds to economic growth. This paper employed the concept of Transect to compensate for data deficiencies in a long temporal series and established the indicator system from three different aspects- “living function, production function, and ecological function”, to measure MRT along China’s Yangtze River Transect. Our analysis showed that living function and production function display an increasing trend from underdeveloped western regions to eastern economically prosperous regions, and represent a high degree surrounding urban agglomerations, while economic growth only leads to a statistically insignificant decreasing trend in ecological function. The MRT resulting from multiple factors is much diverse, complex, sophisticated, therefore, it should be understood within a framework incorporating both endogenous and exogenous factors. According to the results, it is thus important to formulate differentiated managerial countermeasures corresponding to the economic development level rather than the uniform regulations.

Small-scale comparisons help us to understand how habitat features and food availability impact primate abundance. This is particularly useful at sites without human impacts, as it allows for the investigation of the natural factors influencing nesting patterns and great ape abundance. We provide a small-scale study of sympatric great ape nests in an unlogged old-growth forest without poaching activities. We conducted a line transect survey (52 km total effort) around Mbeli Bai, a forest clearing in Nouabale–Ndoki National Park, Congo, applying on-site nest decay rates and assigning nest builder using logistic regression. We found a high occurrence of monodominant Gilbertiodendron dewevrei at Mbeli Bai (34%) that correlates with low great ape densities at Mbeli Bai. Chimpanzees (Pan troglodytes troglodytes) showed a preference for nesting in trees in closed canopy monodominant forest. We found a low percentage of gorilla (Gorilla gorilla gorilla) nests in mixed species forest (35%) and a higher percentage in trees (64%) compared to other study sites. However, generalized additive models found higher gorilla nest encounter rates in mixed species forest with dense understory than in monodominant forest and open understory. We found no indication of higher gorilla densities close to Mbeli Bai than elsewhere, and line transect estimates were lower than the number of gorillas revealed from direct observations. There were substantial differences between our findings and those for nearby sites, demonstrating the utility of small-scale comparisons to further understand the factors determining chimpanzee and gorilla densities within and between sites and the limitations of nest surveys.

This study assesses the occurrence of trace elements (TEs) in sediments of the southern Caspian Sea. A total of 16 shoreline sediment samples and 15 seabed sediment samples along five coastal transects were studied. The mean concentration of TEs follows the order of Zn > V > Cr > Ni > Cu > Pb > Co > As > Sb > Mo > Cd. The TEs had an uneven, heterogeneous distribution within the shoreline and seabed sampling sites. This is due to that the study area comprises a large number of different pollution sources, also different sediment physicochemical characteristics. Levels of individual TEs within the seabed sediment transects were higher where their shoreline sites had higher concentrations, reflecting that the coastal sites play an important role in diffusing the contaminants towards the sea. The main anthropogenic source of TEs in this highly populated region, especially in the western part, is likely a large number of discharge points of greywater entering the sea. In addition, dominant fishing industry, tourism, intense agriculture, and textile and paper industry, as well as several other commercial activities, contribute significantly to the overall loading of TEs. Based on the statistical analyses, the organic matter and mud fraction had a strong explanatory value for the spatial variation of Cu, while oxyhydroxides of Fe and Mn had good explanatory factors to govern the spatial variation of other TEs. Pb and Zn had a relatively high partition coefficient (Kd), reflecting the affinity of these elements to be sorbed to the sediment phase. Cd and Sb had lower Kd, tending to remain in the aqueous phase. Geochemical indices indicated high enrichment of Cd, Sb, Zn, and Pb at a number of sampling sites, reflecting potential local sources of contamination. The Sisangan recreational area was identified as the most contaminated site. From a public health perspective, the non-carcinogenic risk of TEs was significant only at this site. The carcinogenic risks of Pb(II) and As(III) in adults, and Pb(II), Cd(II), and As(III) in children, were tolerable.

Rock-wallabies occupy outcrops, escarpments and cliffs that incorporate structurally complex refuges; because of this, local populations present methodological challenges for monitoring purposes. We describe the development and adaptive modification of a survey technique intended to measure changes in rock-wallaby activity on a site-by-site basis. Twenty spatially independent field sites were collectively sampled across two geological strata using transects consisting of regularly spaced sampling points, with concentric series of fixed-radius circular plots at each sampling point used to count numbers of fresh/recent and/or older rock-wallaby scats. The presence/absence of fresh and/or recently deposited scats was identified as likely to be the more sensitive measure of changing use. Indexes of Activity (IoA) at each field site were subsequently obtained by transect-based sampling at 10 m intervals using 2 m fixed-radius circular plots and recording the presence/absence of fresh/recent scats therein. Derived rock-wallaby IoA ranged between 0.13 and 0.94 across the 20 sites and were approximately normally distributed. Central tendency measures associated with the IoA metrics imply some potential to develop management-themed activity thresholds. Further refinement and potential applications of the approach are discussed.

We measured bird diversity over an 800 m range in altitude to test the factors that influence changes in diversity, in the Atlantic Forest in the state of Sao Paulo, Brazil. We counted forest birds in nine 100 m transects comprising three-point counts, the center of each separated by 200 m. A total of 108 species were found, and diversity was distributed among sampling points and altitude formed a trough-shaped relationship of number of species by area, altitude, and, most strongly, slope. In Principal Coordinate Analysis we found that grouping points by similarity formed three distinct units that were united by altitude: the lowest at near sea level, 100–400 m, and 500–800 m. Thus, we demonstrate that, in the Atlantic Forest, turnover of species with altitude occurs, but unlike higher, often steeper, tropical gradients in Andean forests, where vegetation more clearly changes with elevation, species turnover is more likely to be associated with variables other than changes in vegetation, and which are often not included in studies of the elevation gradient in species richness. The mid-domain effect did not explain altitudinal gradient in diversity, while a quadratic relationship with altitude did, suggesting that reduced abundance and diversity are associated with steeper slopes.

Previous studies have shown changes to the frequencies of hyphal coils and other fungal structures in leafy liverwort tissues across latitudinal transects through Antarctica. Although suggestive of a role of temperature in determining the frequencies of fungal structures, these studies could not exclude the possibility that other factors which alter at lower latitudes—notably liquid water availability—were responsible for the observed patterns of fungal colonisation. Here, in a field experiment in maritime Antarctica, the effects of warming with open top chambers (OTCs) on the frequencies of fungal structures in the leafy liverwort Cephaloziella varians were determined. At five samplings of the experiment taking place 5–10 years after its deployment, OTCs, which increased the summertime temperature of C. varians mats by 1.1 °C, but had no measurable effects on mat moisture concentration, were found to double the frequencies of fine hyphal coils in liverwort tissues. Over the duration of the experiment, the OTCs also significantly increased the frequency of rhizoids on C. varians stems, but had no effects on the frequencies of coarse hyphal coils, dark septate hyphae, hyaline septate hyphae, or hyphal colonisation of rhizoids. Given that C. varians can be recovered from frozen peatbank cores, it is proposed that the abundance of fine hyphal coils in its tissues might be used as a signal of recent climate warming on the Antarctic Peninsula.

Snow water equivalent (SWE) is an important variable in describing global seasonal snow cover. Traditionally, SWE has been measured manually at snow transects or using observations from weather stations. However, these measurements have a poor spatial coverage, and a good alternative to in situ measurements is to use spaceborne passive microwave observations, which can provide global coverage at daily timescales. The reliability and accuracy of SWE estimates made using spaceborne microwave radiometer data can be improved by assimilating radiometer observations with weather station snow depth observations as done in the GlobSnow SWE retrieval methodology. However, one possible source of uncertainty in the GlobSnow SWE retrieval approach is the constant snow density used in modelling emission of snow. In this paper, three versions of spatially and temporally varying snow density fields were implemented using snow transect data from Eurasia and Canada and automated snow observations from the United States. Snow density fields were used to post-process the baseline GlobSnow v.3.0 SWE product. Decadal snow density information, i.e. fields where snow density for each day of the year was taken as the mean calculated for the corresponding day over 10 years, was found to produce the best results. Overall, post-processing GlobSnow SWE retrieval with dynamic snow density information improved overestimation of small SWE values and underestimation of large SWE values, though underestimation of SWE values larger than 175 mm was still significant.

Detailed studies of Ni distribution in peat that is influenced by Ni-rich soil derived from ultrabasic rocks are still limited. The objective of this study was to reveal the characteristics of Ni in peat from Morowali (Central Sulawesi Province, Indonesia) at several depths and distances from the boundary of the ultrabasic mineral soil. Peat was sampled from depths of 0–30, 30–60, and 60–90 cm at distances of 100, 200, 300, 400, 500, and 600 m from the border of the ultrabasic mineral soil in March 2018. Ni characteristics were examined through their total, exchangeable, water-soluble, and adsorbed distributions. The relationships between Ni and some peat chemical properties such as pH; cation exchange capacity; macronutrient contents of K, Ca, and Mg; and micronutrient contents of Fe, Cu and Zn were also observed. The high Ni content in peat at the study transect is caused by an accumulation of Ni transported from elevated areas of mineral soil. Most Ni in peat is bonded to the soil organic exchange complexes. Accumulation of the mineral soil fraction in the peat surface is indicated at distances of 100–400 meters from the ultrabasic mineral soil. Ni distribution in peat at the study transect is mainly governed by a combination of Fe, pH, organic material, water content, peat depth, and distance from ultrabasic mineral soil.

Background and Aims Terrestrial laser scanners (TLSs) have successfully captured various properties of individual trees and have potential to further increase the quality and efficiency of forest surveys. However, TLSs are limited to line of sight observations, and forests are complex structural environments that can occlude TLS beams and thereby cause incomplete TLS samples. We evaluate the prevalence and sources of occlusion that limit line of sight to forest stems for TLS scans, assess the impacts of TLS sample incompleteness, and evaluate sampling strategies and data analysis techniques aimed at improving sample quality and representativeness. Methods We use a large number of TLS scans (761), taken across a 255 650-m2 area of forest with detailed field survey data: the Harvard Forest Global Earth Observatory (ForestGEO) (MA, USA). Sets of TLS returns are matched to stem positions in the field surveys to derive TLS-observed stem sets, which are compared with two additional stem sets derived solely from the field survey data: a set of stems within a fixed range from the TLS and a set of stems based on 2-D modelling of line of sight. Stem counts and densities are compared between the stem sets, and four alternative derivations of area to correct stem densities for the effects of occlusion are evaluated. Representation of diameter at breast height and species, drawn from the field survey data, are also compared between the stem sets. Key Results Occlusion from non-stem sources was the major influence on TLS line of sight. Transect and point TLS samples demonstrated better representativeness of some stem properties than did plots. Deriving sampled area from TLS scans improved estimates of stem density. Conclusions TLS sampling efforts should consider alternative sampling strategies and move towards in-progress assessment of sample quality and dynamic adaptation of sampling.

The general warming trend of the planet cannot be denied (the average global air temperature has increased by approx. 0.85°C between 1880-2012 (IPCC, 2013). The direct consequence of this warming is an increase in extreme weather events and hence in climate risks. The monitoring and assessing precipitation, identifying the physical laws governing its course in order to be able to estimate and forecast it in the future is therefore of great interest nowadays. Using geostatistical spatial analysis methods, this paper aims at identifying the correlations between longitude and precipitation (due to the specificity of the European climate, given by the major influence of the western circulation) and then an estimation - using linear regression equations - of precipitation amounts depending on longitude. Two variables were calculated for the statistical analysis: the proportion of the mean number of days with precipitation ≥ 10 mm of the multiannual mean of precipitation days (≥0,1 mm) and the precipitation ratio between the mean precipitation quantities in summer, compared to those in winter (hereinafter referred to as summer/winter precipitation ratio). The geostatistical analysis carried out on a sample of 40 weather stations aligned from west-south-west to east-north-east argues the existence of a strong correlation between longitude and the multiannual mean of days with precipitation ≥10 mm and between longitude and the summer/winter precipitation ratio.

Earthworms have significant effect on vegetation and soil physical and chemical properties. The relationship between earthworms and biodiversity is important in ecological researches. Therefore, the effects of earthworm on plant diversity and various indices of diversity and richness, as well as physical and chemical properties of soil in shrub, grass and bare vegetation types on exclosure and grazing sites of Miankaleh Mazandaran biosphere reserve is investigated in this work. Accordingly, sampling was carried out randomly-systematically in three different vegetative types (shrubs, grass and bare soil) at 0 to 20 cm depth. Each vegetative types was placed on three transects of 100 m, 10 plots at a distance of 30 m. Earthworm and soil were sampled from the center of each plot of 25 cm × 25 cm. The Simpson and Shannon-Wiener indexes and Margalef and Menhinick richness indices were used to evaluate diversity and richness of species at different grazing intensities. Stepwise regression was used to study the relationship between diversity and richness indices with different earthworm parameters. The results showed that there was significant difference of potassium and nitrogen in vegetation types of both exclosure and grazing sites at P ≤ .01. Furthermore, the organic carbon, organic matter and potassium in the exclosure site and nitrogen and soil moisture in the grazing site are increased by earthworm abundance.

The wild yak Bos mutus was believed to be regionally extinct in Nepal for decades until our team documented two individuals from Upper Humla, north‐western Nepal, in 2014. The International Union for Conservation of Nature (IUCN) seeks further evidence for the conclusive confirmation of that sighting. We conducted line transects and opportunistic sign surveys in the potential wild yak habitats of Humla, Dolpa, and Mustang districts between 2015 and 2017 and collected genetic samples (present and historic) of wild and domestic yaks Bos grunniens. We also sighted another wild yak in Upper Humla in 2015. Phylogenetic and haplotype network analyses based on mitochondrial D‐loop sequences (~450 bp) revealed that wild yaks in Humla share the haplotype with wild yaks from the north‐western region of the Qinghai‐Tibetan Plateau in China. While hybridization with domestic yaks is a major long‐term threat, illegal hunting for meat and trophy put the very small populations of wild yaks in Nepal at risk. Our study indicates that the unprotected habitat of Upper Humla is the last refuge for wild yaks in Nepal. We recommend wild yak conservation efforts in the country to focus on Upper Humla by (i) assigning a formal status of protected area to the region, (ii) raising awareness in the local communities for wild yak conservation, and (iii) providing support for adaptation of herding practice and pastureland use to ensure the viability of the population., Our study carries a global relevance as it presents phylogenetic and haplotype network analyses of wild and domestic yak samples to reveal that the wild yaks in Humla, Nepal, share the haplotype with wild yaks from the north‐western region of the Qinghai‐Tibetan Plateau in China, providing validation to the wild yak rediscovery in Nepal that was based on morphology and behavior of the sighted animals. We also derive phylogeographical inference for the wild yaks in the Nepalese Transhimalayas and discuss their hybridization status while also outlining the conservation implications for the wild yaks that are critically endangered in the country.

3-Hydroxy fatty acids (3-OH-FAs), derived from Gram-negative bacterial outer membranes, have received recent attention for their potential as new terrestrial pH and temperature proxies for palaeoclimate studies. Initial studies from altitudinal transects of contemporary soils – correlating bacterial 3-OH-FA compositions to air temperature and pH – have shown promising results. But the geographical extent of recent calibrations is limited. In this study, we analyse 3-OH-FA lipid distributions in 186 globally distributed soil samples to study the environmental factors controlling the relative distribution of the 3-OH-FA isomers. Our sample-set covers a wide range of temperatures (−0.4 to 27 °C) and pH (3.6–9.2). For the global compilation we find that the ratio of anteiso to normal 3-OH-FAs of the C15 or C17 homologues (RAN15 or RAN17) shows a strong linear relationship with mean annual air temperature (MAAT) (R2 = 0.48, p

An important factor for predicting the effect of increased CO2 on future acidification of the ocean is a proper understanding of the interactions controlling production and dissolution of calcium carbonate minerals (CaCO3). The production and dissolution of CaCO3 in the ocean can be assessed over large spatial scales by measuring seawater calcium concentrations and total alkalinity (AT), yet past studies suggest that there could be large discrepancies between calcium and AT-based balances of the CaCO3 cycle in the North Pacific and Indian Oceans. Here, we analyse water column samples collected along transects in the North Pacific, Southern Ocean, tropical Indian Ocean and Red Sea for their concentrations of calcium, nutrients, and AT. We find that there is an excess calcium over AT anomaly in the top 1000 m of the tropical Indian Ocean water-column. The source of this anomaly is the dissolution of subsurface gypsum deposits in the Red Sea. We find no evidence for calcium-over-AT anomalies in the North Pacific, in contrast to previous studies. Our results show that, in most cases, calcium and AT data agree well and can be used to reconstruct the marine CaCO3 cycle.

Approximately 100 years ago, unregulated harvest nearly eliminated white-tailed deer (Odocoileus virginianus) from eastern North America, which subsequently served to catalyze wildlife management as a national priority. An extensive stock-replenishment effort soon followed, with deer broadly translocated among states as a means of re-establishment. However, an unintended consequence was that natural patterns of gene flow became obscured and pre-translocation signatures of population structure were replaced. We applied cutting-edge molecular and biogeographic tools to disentangle genetic signatures of historical management from those reflecting spatially heterogeneous dispersal by evaluating 35,099 single nucleotide polymorphisms (SNPs) derived via reduced-representation genomic sequencing from 1,143 deer sampled state-wide in Arkansas. We then employed Simpson’s diversity index to summarize ancestry assignments and visualize spatial genetic transitions. Using sub-sampled transects across these transitions, we tested clinal patterns across loci against theoretical expectations of their response under scenarios of recolonization and restricted dispersal. Two salient results emerged: (A) Genetic signatures from historic translocations are demonstrably apparent; and (B) Geographic filters (major rivers; urban centers; highways) now act as inflection points for the distribution of this contemporary ancestry. These results yielded a state-wide assessment of contemporary population structure in deer as driven by historic translocations as well as ongoing processes. In addition, the analytical framework employed herein to effectively decipher extant/historic drivers of deer distribution in Arkansas are also applicable for other biodiversity elements with similarly complex demographic histories.

Motivated to help improve the robustness of predictions of sea level rise, the BRITICE-CHRONO project advanced knowledge of the former British–Irish Ice Sheet, from 31 to 15 ka, so that it can be used as a data-rich environment to improve ice sheet modelling. The project comprised over 40 palaeoglaciologists, covering expertise in terrestrial and marine geology and geomorphology, geochronometric dating and the modelling of ice sheets and oceans. A systematic and directed campaign, organised across eight transects from the continental shelf edge to a short distance (10s of kilometres) onshore, was used to collect 914 samples which yielded 639 new ages, tripling the number of dated sites constraining the timing and rates of change of the collapsing ice sheet. This special issue synthesises these findings of ice advancing to the maximum extent and its subsequent retreat for each of the eight transects to produce definitive palaeogeographic reconstructions of ice margin positions across the marine to terrestrial transition. These results are used to understand the controls that drove or modulated ice sheet retreat. A further paper reports on how ice sheet modelling experiments and empirical data can be used in combination, and another probes the glaciological meaning of ice-rafted debris.

Mountains provide a timely opportunity to examine the potential effects of climate change on biodiversity. However, nature conservation in mountain areas have mostly focused on the observed part of biodiversity, not revealing the suitable but absent species—dark diversity. Dark diversity allows calculating the community completeness, indicating whether sites should be restored (low completeness) or conserved (high completeness). Functional traits can be added, showing what groups should be focused on. Here we assessed changes in taxonomic and functional observed and dark diversity of epiphytic lichens along elevational transects in Northern Italy spruce forests. Eight transects (900–1900 m) were selected, resulting in 48 plots and 240 trees, in which lichens were sampled using four quadrats per tree (10 × 50 cm). Dark diversity was estimated based on species co-occurrence (Beals index). We considered functional traits related to growth form, photobiont type and reproductive strategy. Linear and Dirichlet regressions were used to examine changes in taxonomic metrics and functional traits along gradient. Our results showed that all taxonomic metrics increased with elevation and functional traits of lichens differed between observed and dark diversity. At low elevations, due to low completeness and harsh conditions, both restoration and conservation activities are needed, focusing on crustose species. Towards high elevations, conservation is more important to prevent species pool losses, focusing on macrolichens, lichens with Trentepohlia and sexual reproduction. Finally, dark diversity and functional traits provide a novel tool to enhance nature conservation, indicating particular threatened groups, creating windows of opportunities to protect species from both local and regional extinctions.

Xenobiotic chemical emissions from the informal electronic waste recycling (EW) sector are emerging problem for developing countries, with scale and impacts that are yet to be evaluated. We report an intensive polyurethane foam disk passive air sampling study in four megacities in India to investigate atmospheric organic pollutants along five transects viz., EW, information technology (IT), industrial, residential, and dumpsites. Intraurban emission sources were estimated and attributed by trajectory modeling and positive matrix factorization (PMF). ∑(17)PCDD/Fs, ∑(25)PCBs, ∑(7)plasticizers, and ∑(15)PAHs concentrations ranged from 3.1 to 26 pg/m(3) (14 ± 7; Avg ± SD), 0.5–52 ng/m(3) (9 ± 12); 7.5–520 ng/m(3), (63 ± 107) and 6–33 ng/m(3) (17 ± 6), respectively. EW contributed 45% of total PCB concentrations in this study and was evidenced as a major factor by PMF. The dominance of dioxin-like PCBs (dl-PCBs), particularly PCB-126, reflects combustion as the possible primary emission source. PCDD/Fs, PCBs and plasticizers were consistently highest at EW transect, while PAHs were maximum in industrial transect followed by EW. Concentrations of marker plasticizers (DnBP and DEHP) released during EW activities were significantly higher (p < 0.05) in Bangalore than in other cities. Toxic equivalents (TEQs) due to dl-PCBs was maximum in the EW transect and PCB-126 was the major contributor. For both youth and adult, the highest estimated inhalation risks for dl-PCBs and plasticizers were seen at the EW transect in Bangalore, followed by Chennai and New Delhi.

Coastal dunes are characterised by strong interactions between biotic and abiotic factors along a short gradient from the shoreline to the inland region. We carried out an ecological analysis of the vegetation in a protected area of the Italian coast to evaluate the relationships among species abundance, the occurrence of morphoanatomical traits related to leaves, stems, and roots, and soil variables. Three transects were established perpendicular to the shoreline, with 27 plots distributed in the frontal dunes, backdunes, and temporarily wet dune slacks. An analysis based on community-weighted mean values showed that the pioneer communities of the frontal dunes were dominated by ruderals that are well adapted to the harsh ecological conditions of these environments, showing succulent leaves, high limb thickness values, and low values for leaf dry matter content (LDMC). The backdune vegetation was a mosaic of annual herbaceous and perennial shrub communities showing both ruderal and stress-tolerant strategies (clonality, sclerified leaves, high LDMC values, root phenolics) consistent with less extreme ecological conditions. The dune slack areas were dominated by plants showing adaptations to both arid and flooded environments, such as C4 photosynthesis, amphistomatic leaves, and abundant aerenchyma in the roots. The invasive status, C4 photosynthesis, leaf trichomes, and aerenchyma in the roots were significantly correlated with soil humidity, organic matter content, and pH. These results demonstrate the usefulness of anatomical traits (including root system traits) in understanding the functional strategies adopted by plants. Invasive species tended to occupy plots with high levels of soil moisture, suggesting an avoidance strategy for the harsh environmental conditions of coastal sand dunes. Finally, we suggest including information regarding root systems into coastal monitoring programs because they are directly linked to soil parameters useful in coastal dune management and protection.

Forestry companies have replaced and fragmented the native landscapes, generating a large number of unpaved roads, which can have a negative effect on non-flying invertebrates. Polynoncus bullatus is a common necrophagous beetle species depend on fox scats present on unpaved roads in fragmented landscapes in central Chile. Here, the effect of different habitat types (native forest, clear-cuts and unpaved roads) on the abundance of Lycalopex culpaeus scats as well as abundance and survival of P. bullatus in the fragmented landscape was evaluated. Scats and beetles were counted in seven independent fragments during 6 months and through sampling transects. Both responses and factors were associated with GLM, whereas survival was evaluated with a Kaplan-Meier test. Higher scats abundance was found on unpaved roads than other habitat types. Higher P. bullatus abundance was also significantly associated with unpaved roads than clear-cuts and native forest fragments. An additive model between habitat type and scat abundance was correlated with beetle abundance. Survival was significantly lower in unpaved roads, generating up to 42 % of beetles road-killed. Lycalopex culpaeus response positively to fragmentation defecating more on unpaved roads because foxes use it to move through the landscape. This fact attracts more P. bullatus individuals, being run-over by cars and trucks, representing an ecological trap for beetles. This interaction can be predictable and modeled for any period, length or road type avoiding potential massive road-kill events. Implications for insect conservation. Common and threatened invertebrate species are run-over when minor roads cross valuable natural or protected areas, evidencing the need of advance in road designs compatible with their conservation and mitigating negative impacts of forestry.

Context Line-transect sampling is considered to be a more efficient survey method than point-transect sampling to estimate population densities and abundance of many animal species. Aims In the present study, we tested whether this claim holds true when surveying arboreal fast-moving primate species occurring at low densities, and whether the potential difference in efficiency can be explained by the difference in the size of the survey area between the methods. We further examined the impact of survey effort for point-transect sampling. Methods We conducted line- and point-transect sampling for Geoffroy’s spider monkeys (Ateles geoffroyi) in the same locations and compared the numbers of detected individual monkeys and the probability of their occurrence per survey between the two methods. We further compared the data from point-transect sampling gathered within three different waiting periods. Key results We found a higher probability to detect monkeys and a higher number of monkeys during line-transect sampling than during point-transect sampling, but more spider monkeys were detected at point transects when controlling for the size of the survey area. More monkey detections were made during the first 10 min than during the second and third 10-min periods of point-transect surveys. Conclusions We showed that line-transect sampling is more efficient than point-transect sampling when surveying Geoffroy’s spider monkeys in a flat landscape of tropical forest with homogenous visibility. We discuss factors influencing survey results and recommend 20 min as the maximum waiting time at point transects when surveying arboreal mammals. Implications Our study has provided a quantitative approach to compare efficiency across survey methods for fast-moving arboreal animals that occur at low densities, and supports the use of point-transect sampling in sites where line-transect sampling is not feasible, such as in human-modified landscapes.

The paper assesses the effect of transformation of soil physical properties on the abundance of micromolluscs in the conditions of an urban park. The studies were carried out in Novooleksandrivskiy Park (Melitopol, Ukraine). An experimental polygon was represented by 7 transects with 18 sampling points in each. The interval between the points in the transect, as well as the interval between transects, was 3 meters. The total area of the polygon was 1,134 m2. The tree species growing within the polygon were Quercus robur, Sophora japonica, and Acer campestre. Shrubs were represented by Ulmus laevis, Tilia cordata, Celtis occidentalis, and Morus nigra. The locations of the trees and shrubs were mapped. The crowns of tree and shrub plants formed a dense canopy and a shady light regime. The grass cover was practically absent. The soil mechanical resistance, soil aggregate-size distribution, electrical conductivity of soil, soil moisture and bulk density were measured. We recorded 618 individuals of Vallonia pulchella, 120 individuals of Cochlicopa lubrica, and 58 individuals of Acanthinula aculeata within the surveyed polygon. We extracted three principal components, which could explain 60.9% of the variation in the feature space of the soil properties. The principal component 1 explained 42.0% of the variation of the feature space and depended on the soil penetration resistance throughout the whole profile, aggregate composition, density, electric conductivity and moisture content of soil. This component reflected a tendency for soil penetration resistance and soil density to increase near recreational trails. The principal component 1 was used to indicate the gradient of recreational transformation of the soil. The principal component 2 was able to explain 10.6% of the variation in the feature space. It negatively correlated with the distance from the recreational trail, soil penetration resistance at the depth of 35 cm or more, soil electrical conductivity, and the proportion of aggregates greater than 3 mm in size. This component positively correlated with soil penetration resistance at 0–5 cm depth and the proportion of aggregates less than 0.5 mm in size. This component can be interpreted as a "halo" from the recreational trail, or a gradient of indirect soil transformations adjacent to the zone of intense recreational load. The principal component 3 was able to explain 8.3% of the variation in the feature space. It positively correlated with soil penetration resistance at the depth of 20–40 cm, the proportion of 0.5–7.0 mm aggregates, and soil moisture. It negatively correlated with the proportion of aggregates larger than 7 mm and smaller than 0.25 mm. This component indicated a variation in soil properties that was induced by causes independent of recreational exposure. The extracted gradients of soil properties significantly influenced the abundance of micromollusc populations. The abundance of all species decreased after increase in recreational load. Micromollusc species responded to direct recreational exposure as plateau (C. lubrica) and asymmetric unimodal responses (V. pulchella and A. aculeata).

The current research work is an attempt to apply the basic geological procedures, methods of geological mapping, surface and subsurface interpretation and restoration of balanced and retrodeformed cross sections from the Nizampur basin, Khyber Pakhtunkhwa, Pakistan. The work also includes the documentation of several surface structural features, i.e., anticlines, synclines and different types of folds and faults exposed in the vicinity of study area. Four central thrust faults were recognized named as Kahi Thrusts along the cross sections. These thrust faults carried the older sequences of rocks over the younger sequences in different portion along the measured cross section. The folded and faulted rocks in the area show that stratigraphic framework comprises of Eocene, Paleocene, Cretaceous and Jurassic succession of rocks. There are Eocene rocks existing in the extreme South of the mapped area with addition of older Cretaceous and Jurassic succession and contains simple and large-scale folds, faults and back thrust. Two structural transect were mapped which encounter different folds and faults, i.e., X-sections AB oriented NS and CD oriented NE-SW. Restoration of the structural transects was calculated and assumed that at the formation of Main Boundary Thrust, the study area was exposed to the tectonic forces which prognosticated 19.5% shortening in rock sequences from Jurassic to Eocene succession along the measured cross section A_B.

We explored metal concentrations in wasps from 4 sites near Harare, Zimbabwe, on a 106 km west-east transect. We found elevated concentrations at 2 presumed-polluted sites (a platinum [Pt] mine and a known polluted lake) located near a metal-enriched geological feature (the Great Dyke). A site in urban Harare and a nature reserve served as reference. Only wasps from the 2 presumed-polluted sites had quantifiable Pt. For Cr, Ni, Mg, Se, Fe, Mn, and V, we report the highest concentrations in wasps yet published. Wasps from the presumed-polluted sites had significantly higher concentrations of most metals when compared with wasps from the reference sites, suggesting pollution as a source. Geology, however, differs between the sites. It is probable, therefore, that both geology and pollution contributed to the differences in metal concentrations. Because of its long and narrow dimensions (550 km long and 4-11 km wide), the Great Dyke offers opportunities for comparative studies. Because wasps form a complex part of the food web and ecology, studies on the transfer of metals to wasps' predators are needed, especially given that some birds specialize in feeding on hymenopterans. The rich diversity of wasps (>145 000 species worldwide) occupying multiple different trophic levels is a good indicator, and wasps have a rich potential to join other invertebrates as terrestrial indicators. Environ Toxicol Chem 2021;40:1726-1739. © 2021 SETAC.

Roads have direct and indirect impacts on animals present in the surrounding habitats. Bats have extensive foraging ranges which may include roads, and are therefore particularly affected by them. This study aimed to analyze the effects of roads on bat activity and diversity in the Brazilian savanna. Nine transects were established in protected areas in central Brazil with sampling points at 0, 500, 1,000, and 1,500 m away from roads. At each point, we recorded bat echolocation for 12 h and evaluated the influence of road type and distance from the road on bat activity, diversity, and foraging effort. Season, normalized difference vegetation index (NDVI), and distance to water also were included in the models. We found that species richness in the dry season and activity of open space insectivores were significantly higher on road verges than on areas farther from roads, while foraging effort and activity of edge space insectivores were only influenced by season. The activity of edge space insectivores also increased significantly with increasing distance to water during the rainy season. We suggest that bat individuals do not forage near roads, but rather use them as flyways or cross them to forage in sites outside the protected areas, which can increase the risk of collision with vehicles.

The recovery of tree species composition after disturbance depends on dispersal either from nearby forests or from surviving individuals within the disturbed area. Understanding the influence of proximity to mature forests on species composition of regenerating secondary forests can help in predicting the trajectory of recovery from anthropogenic disturbances. Using forest inventory data from a chronosequence of regenerating secondary forests in the Atlantic Forest of southern Bahia, whereby transects were arranged from the edge of mature forest 100 m into the regenerating area, we calculated community weighted means (CWMs) for traits and the natural distribution ranges of species. We used Generalized Linear Mixed Models to investigate whether site characteristics such as forest age, distance from mature forest edge, soil chemical and physical properties, and canopy openness influence traits and natural distribution of regenerating secondary forest tree species. Results show that species traits were associated with regenerating forest age while the proportion of endemic and widespread species was associated with distance from mature forest and regenerating forest age. Irrespective of distance from mature forest, regenerating secondary forests recruit species with heavy and recalcitrant seeds, but this increased with regenerating forest age. Our results contribute to understanding the effects of forest fragmentation and in restoring forests after deforestation.

Background The analysis of bird community assembly rules is fundamental to understand which mechanisms determine the composition of bird species in urban areas. However, the long-term variation of community assembly rules has not been analyzed yet. The objectives of this study are (1) to analyze the variation of community assembly rules along rural-urban gradients of three cities in central Argentina and (2) to compare the patterns of community assembly between two periods separated by 6 years. Bird surveys were performed along transects in urban, suburban, and rural habitats during 2011 and 2017. Departures from null models that took into account differences in species richness (standardized effect size, SES) were calculated for functional and phylogenetic diversities. Results A total of 57 species were recorded. Bird species richness was higher in suburban than in urban and rural habitats. SES of functional diversity increased over the years and was significantly lower in urban habitats than in rural habitats, showing a pattern of functional clustering in the most urbanized areas and functional randomness in rural ones. Phylogenetic diversity was higher in both suburban and urban habitats than rural ones, and the phylogenetic clustering in rural bird assemblages changed to randomness in suburban and urban habitats. Conclusions Bird communities in urban habitats were phylogenetically random and functionally clustered, evidencing environmental filtering by urbanization. In contrast, bird communities in rural areas tended to be phylogenetically clustered, evidencing that certain clades are adapted to rural areas. The processes structuring bird communities along rural-urban gradients were consistent between the 2 years compared.

Background As one of the main components of land-use change, deforestation is considered the greatest threat to global environmental diversity with possible irreversible environmental consequences. Specifically, one example could be the impacts of land-use changes from oak forests into agricultural ecosystems, which may have detrimental impacts on soil mobilization across hillslopes. However, to date, scarce studies are assessing these impacts at different slope positions and soil depths, shedding light on key geomorphological processes. Methods In this research, the Caesium-137 (137Cs) technique was applied to evaluate soil redistribution and soil erosion rates due to the effects of these above-mentioned land-use changes. To achieve this goal, we select a representative area in the Lordegan district, central Iran. 137Cs depth distribution profiles were established in four different hillslope positions after converting natural oak forests to rainfed farming. In each hillslope, soil samples from three depths (0–10, 10–20, and 20–50 cm) and in four different slope positions (summit, shoulder, backslope, and footslope) were taken in three transects of about 20 m away from each other. The activity of 137Cs was determined in all the soil samples (72 soil samples) by a gamma spectrometer. In addition, some physicochemical properties and the magnetic susceptibility (MS) of soil samples were measured. Results Erosion rates reached 51.1 t·ha− 1·yr− 1 in rainfed farming, whereas in the natural forest, the erosion rate was 9.3 t·ha− 1·yr− 1. Magnetic susceptibility was considerably lower in the cultivated land (χhf = 43.5 × 10− 8 m3·kg− 1) than in the natural forest (χhf = 55.1 × 10− 8 m3·kg− 1). The lower soil erosion rate in the natural forest land indicated significantly higher MS in all landform positions except at the summit one, compared to that in the rainfed farming land. The shoulder and summit positions were the most erodible hillslope positions in the natural forest and rainfed farming, respectively. Conclusions We concluded that land-use change and hillslope positions played a key role in eroding the surface soils in this area. Moreover, land management can influence soil erosion intensity and may both mitigate and amplify soil loss.

Groundwater is a vital water resource in arid and semi-arid areas. Diurnal groundwater table fluctuations are widely used to quantify rainfall recharge and groundwater evapotranspiration (ETg). To assess groundwater resources for sustainable use, groundwater recharge and ETg were estimated using the diurnal water table fluctuations at three sites along a section with different depths to water table (DWT) within a wetland of the Mukai Lake in the Ordos Plateau, Northwest China. The water table level was monitored at an hourly resolution using a Keller DCX-22A data logger that measured both the total pressure and barometric pressure, so that the effect of barometric pressure could be removed. At this study site, a rapid water table response to rainfall was observed in two shallow wells (i.e., Obs1 and Obs2), at which diurnal water table fluctuations were also observed over the study period during rainless days, indicating that the main factors influencing water table variation are rainfall and ETg. However, at the deep-water table site (Obs3), the groundwater level only reacted to the heaviest rainfalls and showed no diurnal variations. Groundwater recharge and ETg were quantified for the entire hydrological year (June 2017–June 2018) using the water table fluctuation method and the Loheide method, respectively, with depth-dependent specific yields. The results show that the total annual groundwater recharge was approximately 207 mm, accounting for 52% of rainfall at Obs1, while groundwater recharge was approximately 250 and 21 mm at Obs2 and Obs3, accounting for 63% and 5% of rainfall, respectively. In addition, the rates of groundwater recharge were mainly determined by rainfall intensity and DWT. The daily mean ETg at Obs1 and Obs2 over the study period was 4.3 and 2.5 mm, respectively, and the main determining factors were DWT and net radiation.

Fire on peatlands takes place not only in areas where preparation for cultivation is in progress, but also in areas that have been cultivated, such as for sago palm growing. One of the important factors that influence the vulnerability of cultivated peatlands to fire is the availability and amount of biomass fuel that easily catches fire, such as ferns, grasses, and broadleaved shrubs in their living as well as dead (litter) stages. The present study concerns the vulnerability of peatland utilized for sago growing by smallholders, focused in Tebing Tinggi Timur, Kepulauan Meranti District, Riau Province. The objectives of this study were to analyze the composition and assess the biomass of fire catchers in the sago palm plantation. Data collection was conducted in three locations in Kepau Baru Village. In each location, a 1000 m-long transect line was drawn and 10 sampling plots of 2 m x 2 m were established along the line with 100 m intervals. Results showed that total biomass of fire catchers in this growing system was averaged at 24681 kg/ha, in which the dead plant fraction was predominating (average at 17478 kg/ha or 70.81%) over the living plant fraction (in average 7203 kg/ha or 29.19%). The latter consisted of ferns that averaged at 2.191 kg/ha or 30.42%, grasses (20 kg/ha or 0.28%), non-woody broadleaved shrubs (581 kg/ha or 8.07%), and woody broadleaved shrubs (4411 kg/ha or 61.24%). The amount of fire catchers in relatively large quantities in this plantation system could magnify fire risk during drier months, especially during El-nino years. Keywords: biomass, fire risk, grasses, non-woody broadleaved shrubs, woody broadleaved shrubs

Coral reefs currently are suffered from natural factors along with increasing anthropogenic activity. Panjang Island, a small reef island located in Jepara Regency, may also be experiencing such conditions. Therefore, this work was aimed to observe the condition of the coral cover of Panjang Island. Line intercept transect was applied to survey the coral cover and mortality index from f ourteen stations. Insitu data consisted of the bottom substrate composition of the reefs and the physical parameters of the sea. The secondary data, i.e. coral reef area maps from 2001 to 2019 were taken from Landsat Image 7 and 8, data of wind were obtained from www.ogimet.com, while tidal data were collected from BMKG. The bathymetry was determined from the Geospatial Information Agency data, s alinity global analysis forecast Phy 001.024 (CMEMS). S ea surface temperature (SST) , and chlorophyll-a distribution were analyzed using ENVI software. The result showed that Panjang Island has a poor to the moderate condition of hard coral. Two out of six categories of abiotic and dead coral were found to be high. T he mortality index of coral was in the high category (average 0.52). During research periods the sea waters were characterized by high sea surface temperature (29.34-30.94°C), chlorophyll -a was also tended to be high (0 -2.65 mg.m -3 ), and an average of salinity was high 32 ‰ . T he weak currents came to all sides of the island, therefore the coral reef was not exposed to extreme currents. T he waves came from the east, then the energy decreases after being blocked by coral reefs on the eastern side of the island, so that coral reefs in the northeast and south sides were safer to be exposed. The results suggest that hydrodynamic ecology directly or indirectly affected the percentage of coral cover and mortality index at the reefs of Panjang Island.

Many studies using surface plankton data from the Continuous Plankton Recorder (CPR) have suggested that micro- and meso-sized zooplankton species/taxa can serve as indicators of environmental change. But while regular CPR sampling would allow for the detection of changes in zooplankton communities, few intra-annual CPR surveys have been undertaken along single transects. We report the temporal variability of zooplankton community structure using CPR data collected along the Japanese monitoring transect (110° E) in December 2014, January 2015, and March 2015. We found zooplankton abundances in both the Polar Frontal Zone (PFZ) and Antarctic Zone (AZ) to increase from December to January, and mean AZ abundance to peak abruptly in January (381.9 ind. m−3) before decreasing to about 25% of that value in March. We attribute changes in total zooplankton abundance to fluctuations in the numbers of the two small dominant copepods, Oithona similis and Ctenocalanus citer. High AZ phytoplankton concentrations in December likely increased surface food availability, influencing population growth, and/or the timing of copepod seasonal ascension. We recommend future CPR surveys include sampling with finer mesh for more accurate determination of abundances of small-sized zooplankton, to better understand the ramifications of climate change on Southern Ocean trophic structure.

The vast clearance of forest and woodland for agriculture with the removal of more than 93% of the native vegetation has decimated the fauna of what is now known as the Western Australian wheatbelt. This clearing has been particularly severe on wandoo woodlands through the wheatbelt. In order to quantify the usefulness of what has been left, three native woodland types were surveyed for avian abundance and diversity, in a large heterogeneous remnant of old-growth woodland, at Dryandra. Birds were counted at 70 points along seven transects, through three woodland types: powderbark wandoo (Eucalyptus accedens), wandoo (E. wandoo) and a brown mallet (E. astringens) plantation. Greater abundance and species richness were detected in E. wandoo woodland, although this is thought to be related to the more mesic and productive low-lying contours of the landscape on which it is situated.

In some situations, environmental DNA (eDNA) metabarcoding is a more accurate tool for measuring species richness of a taxon than conventional methods. Whether this tool can reliably estimate the abundance of a taxon remains unresolved. We examined the reliability of metabarcoding for measuring anuran diversity compared to a commonly used traditional line transect method (TLTM) through the replicate sampling of three visits across 71 waterbodies (ponds or reservoirs) in Liuheng, China. We also investigated the relative contributions of species-specific characteristics and the physiochemical properties of a waterbody on the relative read count across species and waterbodies. We found that eDNA metabarcoding had a higher detection probability for each of seven anuran species found in the sampling region than TLTM. Furthermore, the relative read count estimated by metabarcoding was positively correlated with the density or relative density of individuals identified with the TLTM across waterbodies for every species. Species-specific characteristics of anurans, such as density, relative density, body mass, biomass and relative biomass, accounted for substantial variations in the read count across species and waterbodies, while physiochemical factors, including pH, temperature, water volume, vegetation and elevation, had little effect on the read count. Our results based on robust sampling suggest that metabarcoding enables more reliable and efficient measurements of anuran occurrence at a large scale during a short-term survey (within 15 days) than that obtained by the TLTM, and offers an alternative tool for quantifications of anuran abundance. Density or biomass is better and more reliable indicator of anuran abundance associated with read count than relative density or relative biomass.在某些情况下, 环境DNA (eDNA) 宏条形码 (metabarcoding) 技术在测量类群的物种丰富度上, 比传统的方法更准确。但它能否可靠地估计物种丰盛度, 还不清楚。 基于对中国六横岛71个水体 (池塘或水库) 三次重复抽样调查, 我们比较了eDNA宏条形码技术和传统的样线法 (traditional line transect method) 在监测蛙类多样性方面的可靠性, 并量化了物种特性和水体理化因素对水体中蛙类DNA浓度 (reads数) 的相对贡献。 我们在取样区域发现了7种蛙类物种, 包括入侵种北美牛蛙和6种当地种。eDNA宏条形码技术对每一种蛙类的探测概率均高于样线法。宏条形码技术测定的reads数与样线法估计的每种蛙的密度均呈显著正相关关系。蛙类的密度、相对密度、个体质量、生物量和相对生物量等物种特性, 对水体中的reads数有显著影响, 而水体的理化因素, 如pH值、温度、水体体积、植被盖度和海拔等, 对reads数影响不大。 基于大样本稳健抽样的结果表明, 在短期调查期间 (15天内) , 宏条形码技术在调查大尺度蛙类分布上, 不但比样线法更可靠, 更经济有效, 而且能监测蛙类的丰盛度。密度或生物量等指标与reads数的相关性, 比相对密度或相对生物量等指标高, 是研究eDNA量化关系的可靠指标。.

The riverine barrier hypothesis (RBH) posits that rivers comprise geographical barriers to gene flow for terrestrial organisms, thus promoting genetic differentiation between populations. Here, we explored the RBH on larviparous and pueriparous populations of the live-bearing fire salamander (Salamandra salamandra). While larviparous fire salamanders exhibit a semi-aquatic life cycle (females deposit pre-metamorphic larvae on water), pueriparous salamanders present a fully terrestrial life cycle (females deliver terrestrial juveniles) and, therefore, a greater independence from water for survival and reproduction. We performed a fine-scale sampling of opposite transects in 11 rivers (six and five for larviparous and pueriparous populations, respectively) to test the hypothesis that rivers are more effective barriers for pueriparous salamanders due to their terrestrial life cycle. We carried out individual- and population-based genetic analyses using 14 microsatellites and a mitochondrial marker to examine the extent to which rivers hinder short- and long-term gene flow. We found that rivers are semi-permeable obstacles for both larviparous and pueriparous salamanders, although they appear to be more effective barriers for the latter when rivers with similar attributes are compared. We also found that river width and possibly the presence of crossing structures may influence the genetic barrier effects of rivers in fire salamanders. This is one of the very few studies in amphibians showing how different reproductive strategies influence the barrier effects imposed by rivers.

Line-transect distance sampling is widely used to estimate population densities using distances of observed targets from transect lines to model detectability. When the target taxa are high density, the frequent measuring of distances may make the method seem impractical. We present a method that improves the efficiency of distance sampling when the target species occurs at high density. Only a proportion of targets are measured to model the detection function, and the time saved on the survey is then used to cover a longer total length of transect and accrue a larger ‘count only’ sample. This approach can improve the precision of the population density estimate when the cost of measuring the distance to a detected target is more than half the cost of walking to the next target. We find the optimal proportion of distances to measure that minimises the variance of the density estimate for a fixed survey budget. We quantify how much this optimised strategy increases the precision of the density estimate compared with conventional line-transect distance sampling. We then use simulated distance sampling data to test our expressions, and illustrate circumstances under which the optimised approach would be beneficial using distance sampling data on high-density plants. The simulations indicate that the optimised method delivers benefits in precision, but the magnitude of the benefit is lower than predicted from our expressions, which are based on an asymptotic approximation of the variance. We apply an adjustment to the predicted benefit equation to account for this difference, and show that, in all three plant case studies, the optimised approach could improve the precision gained from a distance sampling survey between 20% and 50%. This new approach could broaden the ecological contexts in which distance sampling is applied, to include estimation of densities of abundant taxa where plots are conventionally used. The method may have interesting applications for other survey types, including multispecies surveys or those using cues or signs that occur at high density.

Soil and geobotanical studies were carried out in a landscape district within the Northern Sarpa lowland of the Caspian Depression in a zone of light-chestnut soil. The collected data made it possible to assess the variation of soil-salinity values typical for dry-steppe plant species and communities in the Republic of Kalmykia and to produce digital models for a geobotanical indication of soil salinity. Geobotanical plots, soil test pits, and boreholes up to 2 m deep were established along a 64-m transect at 1 m intervals. The pNa salinity index was measured in aqueous suspensions of soil samples (1 : 5). As a result, it became possible to determine the salinity at depths of 0–30, 0–50, and 0–100 cm for 12 plant species and 7 plant communities registered on the transect and to distinguish three plant groups based on their tolerance to soil salinity. The first group includes species confined to nonsaline soils (salt concentrations vary within a narrow range). Plants belonging to the second group tolerate a broad range of salinity values and prefer nonsaline soils. The third group consists of salt loving species (halophytes) confined to saline and highly saline soils. Of the seven plant communities registered on the transect, two occur on nonsaline (down to a depth of 2 m) soils (Stipa lessingiana + Festuca valesiaca + Artemisia lerchiana and Stipa lessingiana + Festuca valesiaca + Tanacetum achilleifolium); two others tend to occur in soils that are not saline to a depth of 50 cm (Festuca valesiaca + Artemisia lerchiana + Tanacetum achilleifolium and Artemisia lerchiana + Tanacetum achilleifolium + Artemisia pauciflora); and three communities occur only on soils that are saline from a depth of 25–50 cm (Kochia prostrata + Artemisia pauciflora, Artemisia pauciflora, and Poa bulbosa + Anabasis aphylla). The Classification and Regression Tree (CART) method makes it possible to predict the soil salinity based on the occurrence of plant species identified as predictors. The prediction accuracy is 80% for the 0- to 30-cm layer, 81% for the 0- to 50-cm layer, and 64% for the 0- to 100-cm layer. The following plants have been identified as important (rank > 60) predictors: Kochia prostrata, Tanacetum achilleifolium, Artemisia austriaca, and Festuca valesiaca. Other species feature low prediction importance (validity) values and therefore cannot be used as predictors.

In situ measurements of physical and biogeochemical variables were conducted along a transect in the Exclusive Economic Zone (EEZ) of Qatar during late summer (September 2014) and winter (January 2015) to investigate their vertical, spatial and temporal variability. The study reveals that the water column is characterized by strong stratification during late summer in the deepest station, where the water depth is around 65 m and the surface to bottom temperature variation is around 9.1°C. The water column is vertically homogeneous during winter due to surface cooling and wind mixing. The surface to 23 m water column is characterized by ample dissolved oxygen (DO) during late summer and winter in the offshore regions, however, relatively low DO is found during late summer due to weak mixing and advection under weak winds and currents. Dissolved oxygen drops to hypoxic levels below the summer thermocline, and the winter high DO layer extends up to the bottom. Chlorophyll-a (Chl-a) is relatively high during late summer in the offshore region, while that in the nearshore regions is very low, which is linked to the anthropogenic stresses from the central east coast of Qatar. The results identified in this study fill an essential gap in the knowledge of regional primary production dynamics. Environmental Science Center (ESC) & Department of Biological and Environmental Sciences (DBES), Qatar University (QU)

Observations of the diversity, distribution and abundance of pelagic fauna are absent for many ocean regions in the Atlantic, but baseline data are required to detect changes in communities as a result of climate change. Gelatinous fauna are increasingly recognized as vital players in oceanic food webs, but sampling these delicate organisms in nets is challenging. Underwater (in situ) observations have provided unprecedented insights into mesopelagic communities in particular for abundance and distribution of gelatinous fauna. In September 2018, we performed horizontal video transects (50–1200 m) using the pelagic in situ observation system during a research cruise in the southern Norwegian Sea. Annotation of the video recordings resulted in 12 abundant and 7 rare taxa. Chaetognaths, the trachymedusa Aglantha digitale and appendicularians were the three most abundant taxa. The high numbers of fishes and crustaceans in the upper 100 m was likely the result of vertical migration. Gelatinous zooplankton included ctenophores (lobate ctenophores, Beroe spp., Euplokamis sp., and an undescribed cydippid) as well as calycophoran and physonect siphonophores. We discuss the distributions of these fauna, some of which represent the first record for the Norwegian Sea.

Fatty acid-based lipids comprise a small but important component of soil organic matter. Lipids are indispensable components of soil microbes due to their function as components of membranes and as stores of energy and C. Hence, lipid composition is likely under strong selection pressure and there ought to be strong associations between lipid composition of microbial communities and environmental conditions. Associations between microbial lipids and environment likely involve an integrated combination of differences in lipid headgroups (classes) and fatty acyl chains. However, past studies examining associations between soil lipid composition and environmental conditions have focussed on fatty acids hydrolysed from polar lipids and less is known about headgroups (classes) of polar lipids. The aim of this study was to examine associations between environmental conditions changing with altitude and the intact polar and non-polar lipids of soil microbial communities. We used two altitudinal transects, both spanning from forest through to above the alpine treeline, but separated from one another by ~700 km. Liquid chromatography-mass spectrometry identified 174 intact lipids to the level of class and sum composition. Approximately half of the pool of fatty acid-based lipids was accounted for by two classes of non-polar lipids (diacylglycerol and triacylglycerols), while the other half was dominated by three classes of polar lipids (phosphatidylethanolamine, phosphatidylcholine and diacylglyceryl-N,N,N-trimethylhomoserine). There were large differences among sites in the relative amounts of lipid classes. For example, diacylglyceryl-N,N,N-trimethylhomoserine varied among sites from 5 to 41% of the polar lipid pool, phosphatidylcholine from 31 to 60% of the polar lipid pool, and diacylglycerols from 9 to 53% of the total non-polar pool. Relationships of lipid composition with altitude were weak or differed between transects, and pH was the variable most strongly associated with lipid composition. Variation among sites in the relative abundance of phosphatidylcholine were positively associated with pH, while relative and absolute abundance of diacylglycerol was negatively related to pH. We suggest that the accumulation of diacylglycerol at low pH represents slowed hydrolysis and/or microbial utilisation. A large fraction of variance among sites in lipid composition remained unexplained, which highlights the need for additional research on processes leading to production and consumption of fatty acid-based lipids.