1. Data on reproductive features of temperate terrestrial isopods species is well-known, for some species this knowledge is still incipient. Armadillidium tunisiense is a newly discovered and endemic Tunisian with an only recent study concerning its breeding patterns. 2. Seen the interspecific and intraspecific variations due to local variations in environmental conditions. We decided to describe the main characteristics of A. tunisiense’s life cycle from the Chambi mountain, the highest point in Tunisia, by determining the population structure; the reproduction dynamics, the sex ratio and fertility. 3. The breeding patterns and the reproductive cycle of A. tunisiense were studied on 2908 individuals collected on regular bias from July 2009 to July 2011 from the Chambi mountain. Our specimens were divided into six categories. Where females were followed from the day of collection until their death. An in-depth study of a well-defined number (35 specimens) of reproductive females were desiccated to define the fertility by counting the eggs contained in the marsupium. 4. We found that A. tunisiense from the Chambi mountain is a semelparous species with a seasonal reproductive pattern, characterized by a reproduction period followed by a sexual rest. Also, we could’ve confirmed the positive relationship between the sizes of ovigerous females and fertility. With 5 eggs recuperated in a 5.2 mm female while 33 eggs were encountered in an 8 mm female. As well as for the sex ratio which characterized by fluctuation (0.49-1.12), but mainly in favor of females over that of males. 5. The combined results of the previous study and ours maintain on the role of environmental conditions that interfere to explain the interspecific variations were observed for the launch and the duration of the reproduction period. Thus, altitude might confirm the intraspecific variations between both studied populations of A. tunisiense.

Seed predators have the potential to act as agents of natural selection that influence seed traits. Accordingly, plants deploy a variety of mechanisms (e.g. resistance and tolerance strategy) to lessen the impact of predation on seed crop or on an individual seed. In this study, we found a novel mechanism (i.e. cloning strategy) in a tropical plant species in countering animal predation. We found both rodent damaged and human artificially damaged seed fragments of a large-seeded tree Garcinia xanthochymus in the Xishuangbanna tropical forest of China could develop into seedlings in both field and laboratory conditions. G. xanthochymus seed has no endosperm in seeds, and its seed tissue own strong capacity of differentiation and cloning. Seed damage would negatively affect seedling growth and germination, but the seed germination rate was remarkably high. Our study suggests that, as a novel strategy countering animal predation, seed cloning would play a significant role in stabilizing the mutualism between plant and animals.

Vegetation restoration can not only preserve soil and water and reduce soil erosion, but also improve soil properties and quality significantly. However, different vegetation types have different effects on soil organic carbon fractions and enzyme activities. In this study, we examined the response of soil organic carbon fractions and enzyme activities to different types of vegetation (i.e., Xanthoceras sorbifolia (XS), Hippophae rhamnoides (HR), Caragana korshinskii (CK), Grassland (GL)) on the northern Loess Plateau. The contents of soil organic carbon (SOC), microbial biomass carbon (MBC), easily oxidized carbon (EOC) and particulate organic carbon (POC) and the enzyme activities (i.e., amylase, catalase, urease and surase) were investigated at the end of plant growth. We found that the content of soil SOC fractions and enzyme activities upper > lower layer in each vegetation types except for MBC and catalase activity. There was no significant difference in MBC content and catalase activity between soil layers. The EOC and amylase of GL vegetation were significantly higher than other vegetation types. POC, SOC, urease and sucrase were significantly higher in SX vegetation than other vegetation types. The maximum soil MBC content was found in HR vegetation, and among the four vegetation types, the MBC content showed significant differences in lower layer, but no significant difference in the surface soil. Correlation analysis showed that the MBC significant influenced on the catalase activities; POC significant affected urease and sucrase activities; SOC extremely significant influenced on the urease and sucrase activities. Therefore, vegetation type was an important factor affecting the change of soil enzyme activities and carbon fractions on the Loess Plateau.

Exploring the dynamics of natural regeneration facilitates the understanding of the mechanisms of community assembly and biodiversity formation in tropical forests. However, there is still a lack of convincing evidence related to regeneration, especially for threatened tropical plant communities. Dacrydium pectinatum is a constructive and an endangered species in the tropical mountain forests of Hainan Island. A total of 204 regeneration plots of 5 m × 5 m were investigated along environmental axes of temperature and precipitation in the northwest (Bawangling, 90 plots), southwest (Jianfengling, 90 plots) and southeast (Diaoluoshan, 24 plots) of Hainan Island. We examined the variation in community structure, mortality, density and species richness at the three sites and analyzed the key environmental drivers that affect regeneration. The results showed that the mortality of adults, seedlings and saplings was the lowest in Diaoluoshan, followed by Jianfengling and Bawangling. The peaks in the density and species richness of regenerating individuals were limited to mid-elevations. Elevation, soil total nitrogen, soil available phosphorus, canopy density and adult density were significantly correlated with density and species richness. All findings indicate that at a broad landscape scale, variation in precipitation and temperature due to latitude, longitude and elevation is the dominant cause for the formation of the regeneration dynamic patterns along distinct environmental axes and that the intermediate environmental conditions at middle elevations contribute to regeneration. At the community level, habitat preferences related to elevational factors, soil total nitrogen, soil available phosphorus and forest gaps play a key role in regeneration success. Biological mechanisms (negative density-limiting effects) also have an important effect. We recommend various actions to improve the protection of D. pectinatum, such as the prevention of habitat destruction, appropriate thinning of high-density stands, and strengthening of niche research, and increase biodiversity.

Honey bees and bumble bees are generalist eusocial bees that collect resources from a variety of plant taxa. Both bee species have distinct foraging strategies that affect patterns of resource collection, with implications for designing pollinator friendly habitat management schemes. Using a comparative approach, we examined the pollen foraging patterns of the honey bee (Apis mellifera) and common eastern bumble bee (Bombus impatiens) in a suburban-agricultural landscape. We tested predictions stemming from the bees’ known foraging strategies of dance communication or trapline foraging, respectively, and collected pollen from returning foragers of each bee species over five time periods at each of three sites. We quantified the frequency of flower constant foragers, the richness and diversity of pollen collected by a colony, and whether honey bees or bumble bees show preferences by comparing the taxonomic identity of pollen collected to resources available. Analyses were done at the pollen morphotype and plant family levels. Within a foraging trip, honey bees foraged on a single plant family more frequently than bumble bees throughout the summer, except during July, when both species demonstrated a similar frequency of flower constancy. Pollen diversity was greater for bumble bees relative to honey bees, and both bee species collected less diverse pollen in June. Finally, bumble bees preferred the Fabaceae_Tricolporate pollen morphotype (Trifolium repens or Medicago sativa), but avoided Apiaceae, while honey bees foraged randomly showing no evidence of preference. These results support the hypothesis that species level foraging strategies affect how bees exploit pollen resources. Explicitly considering pollinator foraging strategy when designing agri-environment schemes will inform the most appropriate arrangement of floral resources within developed landscapes, thereby promoting both pollinator health and pollination services of bee-dependent crops.

This paper studied the potential mechanism of form drag from emergent vegetation by the effective combination of experimental verification and numerical simulation. The rigid cylindrical sticks arranged in the open channel were used to simulate vegetation and experiments on flow velocity distribution characteristics in open channel with different vegetation density and vegetation arrangement forms were carried out. Based on the new expression of hydraulic radius from the recent paper, it indicates the form drag from vegetation is closely related with the wake volume near the vegetation. The relationship between the wake volume and form drag is proposed and verified by different experimental conditions. Based on this relationship, the experimental results show that the resistance form of vegetation in vegetated open channels can be divided into: K-type and D-type based on different sticks arrangement within one vegetation patch. The calculated values and measured values achieve a good agreement under different experimental conditions. Meanwhile, numerical simulation based on SAS turbulence model was conducted and the simulation results also fit well with the experimental values so more complex experimental conditions are simulated by numerical simulation method. The results of this study will provide a theoretical basis for the layout of vegetation in the ecological open channel.

One of the most important drivers of the coexistence of species is the resource heterogeneity of a certain environment. Thus, many studies in different ecosystems have been carried out to test whether species richness is affected by resource heterogeneity. To date, only few studies have measured light and soil resources heterogeneity in forests to investigate its influence on plant diversity. In this study, the aim was to determine (1) which resources have major influences on forest understory plant diversity; (2) the influence of the forest canopy on the heterogeneous distribution of light and soil resources; (3) whether heterogeneity of resources increases understory plant species richness; and (4) if stand structural complexity is an indicator for understory plant species richness. Measures of stand structural complexity were obtained through inventories and remote sensing techniques in 135 study plots of temperate forests, established along a gradient of forest structural complexity. We surveyed vegetation, measured light conditions and soil properties six times in each of all plots. We calculated the standard deviations of these parameters to receive a measure of heterogeneity. Results showed that heterogeneity of light and soil C:N ratio increases with increasing stand structural complexity, increasing light heterogeneity leads to increased understory plant species richness, and finally, an increase of stand structural diversity predicts an increase in understory plant diversity. The study clearly shows that resource heterogeneity theory plays a major role in the coexistence of understory plant species and hence its diversity. These results suggest that understory plant diversity could be increased in forests managed by single tree harvesting by spatially varying the quantities of trees to be logged to create a more heterogeneous understory light environment.

Manual assessment of flower abundance of different flowering plant species in grasslands is a time consuming process. We present an automated approach to determine the flower abundance in grasslands from drone images using a deep learning (Faster R-CNN) object detection approach, which is trained and evaluated on data of five flights and two sites. Our deep learning network is able to identify and classify individual flowers. The novel method allows generating spatially explicit maps of flower abundance that meets or exceeds the accuracy of the manually counted extrapolation method and is less labor intensive. The results are very good for some types of flowers with precision and recall being close to or higher than $90\ \%$. Other flowers are detected poorly due to reasons such as lack of enough training data, appearance changes due to phenology or flowers being too small to be reliably distinguishable on the aerial images. The method is able to give precise estimates of the abundance of many flowering plant species. The collection of more training data will allow better predictions in the future for the flowers that are not well predicted yet. The developed pipeline can be applied to any sort of aerial object detection problems.

Evolutionary theory predicts that a host infected with a parasite that reduces its future survival and/or fecundity should be selected towards an increased investment in current reproduction. In this study we use the cestode Ligula intestinalis and its intermediate fish host Engraulicypris sardella in Wissman Bay, Lake Nyasa (Tanzania) as a model system. Using data about infestation of E. sardella fish hosts by L. intestinalis collected for a period of 10 years, we explored (i) whether parasite infection affects the fecundity of the fish host E. sardella and (ii) whether host reproductive investment has increased at the expense of growth at maturity. We found that L. intestinalis had a strong negative effect on the fecundity of its intermediate fish host. For the non-infected fish we observed an increase in relative gonadal weight over the study period, while somatic growth at maturity decreased during the study period. Our findings suggest that the cestode L. intestinalis might have selected for increased investment in current reproduction in its fish host E. sardella in Lake Nyasa. This calls for further studies to assess whether these changes reflect plastic or evolutionary responses. We also discuss the synergy between parasite and fishery-mediated selections as a possible explanation for the decline of E. sardella stock in the lake. KEYWORDS Engraulicypris sardella; Ligula intestinalis; life history evolution; selective agents; parasitism; fishing.

1. Trees are characterised by the large number of seeds they produce. Although most of those seeds will never germinate, plenty will. Of those which germinate, many die young, and eventually only a minute fraction will grow to adult stage and reproduce. Is this just a random process? Do variations in germination and survival at very young stages rely on variations in adaptations to microgeographic heterogeneity? and do these processes matter at all in determining tree species distribution and abundance? 2. We have studied these questions with the Neotropical Symphonia syngameon. In the Guiana shield, Symphonia are represented by at least two sympatric taxa or ecotypes, Symphonia globulifera found almost exclusively in bottomlands, and a yet undescribed more generalist taxon/ecotype, Symphonia sp1. A reciprocal transplantation experiment (510 seeds, 16 conditions) was set-up and followed over the course of 6 years to evaluate the survival and performance of individuals from different ecotypes and provenances. 3. Germination, survival, growth, and herbivory showed signs of local adaptation, with some combinations of ecotypes and provenances growing faster and surviving better in their own habitat or provenance region. S. globulifera was strongly penalised when planted outside its home habitat but showed the fastest growth rates when planted in its home habitat, suggesting it’s a specialist of a high-risk high-gain strategy. Conversely, S. sp1 behaved as a generalist, performing well in a variety of environments. 4. Synthesis: The differential performance of seeds and seedlings in the different habitats matches the known distribution of both ecotypes, indicating that environmental filtering at the very early stages can be a key determinant of tree species distributions, even at the microgeographic level and among very closely related taxa. Furthermore, such differential performance also contributes to explain, in part, the maintenance of the different ecotypes in the Symphonia syngameon living in intimate sympatry despite occasional gene flow.

The Qilian Mountain Grassland is an important animal husbandry production base in northwestern China. Horses, cattle and sheep are the main livestock, which are widely distributed in the desert grassland and alpine meadow around the Qilian Mountains. Grazing livestock produce large amounts of feces, and the germinated seeds in the feces constitute the dung seed bank of the grassland. Research on the size, composition and distribution of livestock manure seed bank in the Qilian Mountain grassland may provide a deeper understanding of the interaction between grass and livestock and help inform comprehensive management practices for grazing livestock. In mid-October 2018, we collected the dung of horses, cattle and sheep in the alpine meadows and desert grasslands of the Qilian Mountains and measured the composition and size of the dung seed bank by the greenhouse germination method. The dominant species of seeds in the dung collection site were also collected to determine the relationship between the size and composition of the dung seed bank and the seed traits (mass and shape). A total of 30 different species of seedlings germinated from the dung of the three livestock. Of these, 22 species (73% of total) were perennial. The seedling densities (g-1 dung) of horse, cattle and sheep were 5.23, 3.27 and 0.72, respectively. The species richness, species diversity, and the Jaccard coefficients of similarity between dung seedling and aboveground vegetation of horse dung were significantly greater than those of cattle and sheep (P < 0.05). Regression analyses indicated that medium-sized (10–30 mg) and spherical (0.04–0.10 shape index) seeds had the greatest germination potential. Our study suggests that, of the three livestock species tested, the horse dung seed bank contributes most to grassland recovery and restoration of the Qilian Mountains.

The cultivation of artificial grassland, which requires regular sowing and harvesting, is an important and common practice in grassland management and restoration on the Qinghai-Tibetan Plateau (QTP). However, the key factors and successional processes that determine its interannual variability of net ecosystem exchange (NEE) remains unclear. In this study, we analyzed 6 years of eddy covariance observations, quantified seasonal and annual NEE, net carbon uptake period length (CUP), two largest carbon emission periods length (CEPs), and daily minimum and maximum NEE (NEEmin, NEEmax) responses to management measures in an alley silvopasture system with planted Elymus nutans on the QTP. We examined NEE variations before and after sowing and harvesting and investigated how sowing and harvesting managements affect NEE. The five-year life cycle study revealed that this artificial perennial grassland was a weak net carbon sink with an uptake of -180 g C m–2 per plant cycle (2012–2016). Inter-annual variations in NEE was determined by CUP and the first largest carbon emission periods (CEP1). Sowing delayed the beginning of CUP (BCUP) by about 42 days and caused spring C uptake to decline by -36 g C m–2. In contrast, harvesting caused the ending of CUP (ECUP) to advance about 25 days, and caused a decease of autumn C uptake about -33 g C m–2. Sowing and harvesting shortened the CUP and extended the CEP1, which reduces the carbon sequestration potential of the artificial grassland. Based on our results, we recommend that policy makers and authorities consider the effect of timing of sowing and harvesting on C sequestration. Our results provide a new insight for grassland management and the inter-annual variability of NEE on climate mitigation and regional sustainability.

Birds have been observed to have dietary preferences for unsaturated fatty acids (FAs) during migration. Polyunsaturated fatty acids (PUFAs) increase the exercise performance of migrant birds; however, PUFAs are also peroxidation prone and might therefore incur increased costs in terms of enhanced oxidative stress in migratory individuals. To shed light on this potential constraint, we analysed plasma FA composition and estimated the susceptibility to peroxidation of migrants and residents of the partially migratory common blackbird (Turdus merula) at a stop-over site during autumn migration. As predicted, migrant birds had higher relative and absolute levels of PUFAs compared to resident birds. This included the strictly dietary ω-3 PUFA α-linoleic acid, suggesting a dietary preference for these fatty acids in migrants. Interestingly, the FA unsaturation index, which is an index of lipid peroxidation susceptibility, did not differ between migrants and residents. These findings suggest a mechanism where birds alter their levels of metabolic substrate to increase exercise performance without simultaneously increasing the risk of lipid peroxidation and oxidative stress. In summary, our results are in line with the hypothesis of increased exercise performance being constrained by oxidative stress during migration, which is manifested in changes in the composition of key FAs to retain the unsaturation index constant despite the increased levels of peroxidizable PUFAs.

The deficiency of pollen grains for ovule fertilization can be the main factor limiting plant reproduction and fitness. Due to ongoing global changes, such as biodiversity loss and landscape fragmentation, a better knowledge of the prevalence and predictability of pollen limitation is challenging within current ecological research. In our study we used pollen supplementation to evaluate pollen limitation (at the level of seed number and weight) in 22 plant species growing in a wet semi-natural meadow. We investigated the correlation between the Pollen Limitation index (PL) and floral traits associated with plant reproduction or pollinator foraging behaviour. We recorded significant pollen limitation for approximately 41% of species (9 out of 22 surveyed). Seven species had a significant positive response in seed production and two species increased in seed weight after pollen supplementation. Considering traits, PL significantly decreased with the number of pollinator functional groups. The relationship of PL with other examined traits was not supported by our results. The causes of pollen limitation may vary among species with regard to 1) different reproductive strategies and life history, and/or 2) temporary changes in influence of biotic and abiotic factors at a site.

Leaf soluble sugars and starch are important components of nonstructural carbohydrates (NSCs), which are crucial for plant growth, development, and reproduction. Although there is a large body of research focusing on the regulation of plant NSC (soluble sugars and starch) concentrations, the response of foliar NSC concentrations to continuous nitrogen (N) and phosphorus (P) addition is still unclear, especially in tropical forests. Here, we used a long-term manipulative field experiment to investigate the response of leaf NSC concentrations to continuous N and P addition (3-, 5-, and 8-year fertilization) in a tropical forest in southern China. We found significant species-specific variation in leaf NSC concentrations in this tropical forest. Phosphorus addition dramatically decreased both leaf soluble sugar and starch concentrations, while N addition had no significant effects on leaf soluble sugar and starch concentrations. These results suggest that, in plants growing in P-limiting tropical soil, leaf NSC concentrations are regulated by soil P availability rather than N availability. Moreover, the negative relationships between NSC concentrations and leaf mass per area (LMA) revealed that NSCs could supply excess carbon (C) for leaf expansion under P addition. This was further supported by the increased structural P fraction after P fertilization in our previous study at the same site. We conclude that soil P availability strongly regulates leaf starch and soluble sugar concentrations in the tropical tree species included in this study. The response of leaf NSC concentrations to long-term N and P addition can reflect the close relationships between plant C dynamics and soil nutrient availability in tropical forests. Maintaining relatively higher leaf NSC concentrations in tropical plants can be a potential mechanism for adapting to P-deficient conditions.

Despite centuries of exploration, our perception of potential mechanisms determining the species community assemblage is still in infancy . Longhorn beetle as an insect with larval stage feeds on the xylem of plants or trees, the relative importance of biotic (host-specificity) and abiotic (climate gradients) processes to determining their community compositional variation is unknown. In the aim of exploring the knot, we therefore designed the experiment throughout multiple spatial scales (macro/regional and micro/local) along tropical to temperate climate gradients at the Indo-Burma biodiversity hotspot, to examine to what extent biotic and abiotic factors may exert a significant influence on longhorn beetle species composition assembly, and whether this relationship is scale dependent. The relationships between longhorn beetles species composition variation and biotic and abiotic factors were examined using β-dissimilarity indices comparison，NMDS analysis , variation partitioning based on RDA, linear mixed-effect model and mantel test. We found a positive relationship between the species compositional variation of both beetle and plants, in which longhorn beetle species dissimilarity apparently track changes in plant dissimilarity both at macro/regional and micro/local scales. NMDS analysis showed that abiotic factors have prominent influence to the longhorn beetle community assemblage. Variation partitioning and linear mixed-effect model retained significantly correlated Environment and plant diversity metrics for beetle diversity. Thus, we concluded that: 1) biotic and abiotic factors collaboratively shaped longhorn beetle community composition along various spatial scales; 2) the relative importance of abiotic and biotic variation explaining the longhorn beetle community composition vary by spatial scale; and 3) biotic interactions have prominent effect to longhorn beetle community composition at local-scale while macroclimatic gradients impose the most control on it at macro-scale. Besides, our study showed that the influence of dispersal limitation in the species assembly of longhorn beetles from tropical to temperate area was minor compared with plant communiti

Due to the urbanization and human invasion of the natural environments, a great deal of changes have occurred on the food composition and feeding ecology of several animals especially those are sharing humans their habitats in fields, wadis and gardens. The Desert Hedgehogs Paraechinus aethiopicus populations inhabiting different localities in Saudi Arabia were studied by using stomach contents analysis between February 2015 and October 2019. Precise analysis of 55 stomach contents of hedgehogs showed that the food of The Desert Hedgehogs Paraechinus aethiopicus is highly diverse and highly influenced with effect of humans on the environment includes cooked rice, insects, plant materials, egg shells, worms, garbage and remains of mammals and birds. Diet composition showed seasonal variations that are apparently associated with changes in the availability of different food items. The present results clearly showed that The Desert Hedgehogs Paraechinus aethiopicus is a generalist animal, capable of adapting to a great variety of dietary compositions in the study sites.

Abstract: In this paper the feeding index (FI), Gastro somatic index (GaSI) and Food Prevalence Index (FPI) of freshwater prawn M. assamense peninsulare were evaluated to assess the quantity and kind of food which this prawn consumes in the Rawasan stream. A total of 401 prawns were collected for an interval of two years form five selected site in Rawasan stream of Garhwal in Central Himalaya, India from August 2013 to July 2015. Collected prawn was in the size range of 20-75 mm in male and 24-65 mm in female in total length during the study period. The stomach contents of 10 collected specimens were examined monthly and observed that 35% of the stomach was full or semi-full and 15% stomach were empty. Highest Gastro somatic value (Mean±SE) was obtained 2.95±0.80 during June in the male and 3.25±0.44 during May in the female. After that, it gradually decreased in both the sex and this repeated in cyclic pattern each year. More or less a similar trend was reported in the feeding index value during the study indicate a significant relationship between feeding intensity and Gastro somatic index. Highest Food Prevalence Index (FPI) was seen in fragment of animals in both sex, which was (88.48) in male and (58.26) in female prawn and lowest FPI value in sand debris 7.9 and 5.7 in male & female prawn respectively. Main food items were fragment of plants & animal, diatoms, algae, and sand. In overall, the results show that this prawn is selectively abstemious

Temporal partitioning is an important mechanism for carnivore mammals that live in sympatry in current forest remnants. We evaluated whether temporal partitioning would facilitate coexistence among carnivores in a tropical forest and its adjacent human-related area, as well as if there is a possible correlation between the activity patterns of these carnivores and their potential prey. We used camera traps and circular statistics to explore the degree of temporal overlap between dominant and subordinate predators, as well as between predators and their potential preys. Pumas (Puma concolor) were less active when jaguars (Panthera onca) were more active. Overall, ocelots (Leopardus pardalis) and crab-eating foxes (Cerdocyon thous) presented either a strong or a weak temporal partitioning with jaguars and pumas, respectively, but apparently spatial or dietary segregation might facilitate more their coexistence with these large predators. Tayras (Eira barbara) and coatis (Nasua nasua) were diurnal and, therefore, did not overlap temporally with nocturnal carnivores, except pumas. In the human-related area, ocelots were mostly nocturnal and pumas diurnal, probably due to the temporal activity of their related preys. Our findings suggest that temporal partitioning may allow coexistence between our studied predators in one of the largest Atlantic Forest remnant in Brazil, but preys have an important role, shifting the activity pattern of their predators according to the studied area.

Diatoms are a globally successful and eukaryotic photosynthetic group with an ornamented silica external wall. The relationship between their thecal diversity and habitat means that diatoms can be used as bioindicators to characterize the aquatic environment. To estimate the distribution and diversity of diatom communities during winter in South Korean coastal waters, we collected phytoplankton samples from 114 coastal sites. We applied the unweighted pair-group technique using the arithmetic averages clustering method to cluster the sampling sites—apart from those where the biota consisted of other groups, such as dinoflagellates—into four ecoregions: Yellow Sea (YS), Southern Sea (SS), Southern East Sea (SES), and Northern East Sea (NES). Indicator species analysis in each ecoregion led to the selection of tychoplanktonic, chain-forming, stalk-forming, and psychrophilic indicator diatoms, each of which represented a planktonic lifestyle associated with one of the four ecoregions. This study shows the diatom community to serve as bioindicators of Korean coastal water ecoregions, and the subsequent seasonal survey will provide a starting point for the improved understanding of Korean diatom-based ecoregions, in both time and space.

Recurrent sea urchin mass mortality has recently affected eastern Atlantic populations of the barren-forming sea urchin Diadema africanum. This new episode of die-off affords the opportunity to determine common meteorological and oceanographic conditions that may promote disease outbreaks. The population dynamics of this sea urchin species are well known—urchin barrens have persisted for many decades along most of the coastlines off the archipelagos of Madeira, Selvages and the Canary Islands, where they limit macroalgae biomass growth. However, this new and explosive mortality event decimated the sea urchin population by 93% on Tenerife and La Palma Islands. Two severe episodes of southwestern rough sea that lead to winter storms, in February 2010 (Xynthia) and February 2018 (Emma), preceded both mass mortality events. The autumn and winter months of those years were anomalous and characterized by swells with an average wave height above 2 m that hit the south and southwest sides of the islands. The amoeba Paramoeba brachiphila was the only pathogen isolated this time from the moribund and dead sea urchins, suggesting that the amoeba was the primary cause of the mortality. This new sea urchin die-off event supports the “killer-storm” hypothesis that has been already described for western Atlantic coasts. These anomalous southwest storms during winters generate pronounced underwater sediment movement and large-scale vertical mixing, detected in local tide gauge, which may promote paramoebiasis. This study presents valuable insights about climate-mediated changes in disease frequency and its impacts on the future of coastal marine ecosystems in the Atlantic.

1. The abundance of UV-B absorbing compounds (for example p-Coumaric acid, pCA) within pollen-grain sporopollenin has been proposed as a proxy for reconstructing past changes in surface solar radiation, but drivers of the variation of these compounds in pollen grains remains poorly understood. 2. One important consideration is that the physiological response that results in the production and timing of pCA in pollen remains poorly understood. This calls for studies that explicitly tests the temporal resolution and plasticity of the response of pCA in pollen under field conditions. 3. To address this, we conducted two parallel experiments. First, we measured pCA in four Pinus spp. from Geneva in two consecutive years to investigate the impact of natural variation in ambient solar radiation, and differences in responses between species. Second, we covered pollen cones on Pinus sylvestris trees in Bergen with 90% shading cloth one month before dehiscence and compared the amount of pCA in pollen from shaded and sun-exposed cones from the same tree. 4. Between years, in Geneva, Pinus spp. produced 31% more pCA in 2014 than in 2013, with higher levels of solar radiation also observed in 2014. pCA content also showed strong species-level variation, largely reflecting differences in pollen size between species. Experimentally shaded Pinus sylvestris pollen produced 21% less pCA than fully exposed pollen. 5. Our work demonstrates a plastic response in the production of UV absorbing compounds (pCA) to inter-annual and experimentally induced variation in ambient solar radiation in Pinus spp. pollen. This supports pCA as a highly responsive proxy for early-season solar radiation. We also find strong species-level variation in pCA content in pine pollen, likely related to pollen grain size, which should be accounted for in reconstructions from sites with multiple Pinus species present.

Mulberry intercropped with alfalfa is a popular agroforestry system in China, which can produce high forage yields with high protein. To investigate the advantages of intercropping as well as the responses of mulberry-alfalfa intercropping systems to nitrogen application, we studied changes in the soil microbial communities and physiochemical properties in the rhizosphere of intercropped mulberry and alfalfa under nitrogen application. Nitrogen application increased available nitrogen contents (AN) and activities of urease (SUR) in rhizosphere soil of mulberry and alfalfa, but reduced soil organic canmatter (OM), irrespective of the cropping system (monoculture or intercropping). Nitrogen application increased soil pH in the rhizosphere of mulberry and alfalfa in monoculture, but reduced soil pH in the intercropped system. Nitrogen application and intercropping enhanced the soil water content (SWC) in mulberry rhizosphere soil and decreased SWC in alfalfa rhizosphere soil. We observed significant differences in the microbial communities inhabiting mulberry and alfalfa rhizosphere soils, indicating that mulberry and alfalfa are strategically complementary in terms of carbon sources. The Shannon-Weaver (H’), Simpson index (D), and McIntosh diversity (U) values were higher in rhizosphere soil of intercropped mulberry compared with mulberry in monoculture without nitrogen supply. There were no significant differences between mulberry in monoculture with nitrogen application (MNE) and mulberry intercropped alfalfa without nitrogen (M0). The results of the principal components analysis showed that MNE and M0 clustered in the scattered plots. We found no significant differences for H’ and D between monoculture and intercropping alfalfa systems, irrespective of the nitrogen application. Nitrogen application, intercropping, and intercropping with nitrogen increased the numbers of carbon sources, and relative use rates exceeded 4%. Nitrogen application and intercropping reduced the numbers of available carbon sources in alfalfa. Redundancy discriminatory analysis results suggest that pH and SWC were positively related with mulberry treatments and negatively with the alfalfa treatments.

The complex and enormous diversity of microbiome associated with plant roots is important for plant health and is shaped by numerous factors. This study aimed to unravel the effects of a pesticide-fertilizer combination on the rhizosphere microbiome of field-grown sugarcane. A field trial on sugarcane was conducted in Zhanjian city, Guangdong Province of China, and bulk soil and rhizosphere samples were collected 3 weeks after planting. We examined the effects of clothianidin and/or organic fertilizer treatments on the composition, diversity, and function of rhizosphere microbial communities using 16S rRNA gene and ITS1 gene amplicon sequencing. Compared with the controls (no pesticide or fertilizer used), the microbial community that resulted from treating with the pesticide-fertilizer (SPF) had a higher relative bacterial diversity and abundance, as well as contributing more comprehensive functions to sugarcane. The bacterial and fungal compositions at different taxonomic levels affected by clothianidin in the SPF and SP (with pesticide addition) were different from the effects experienced in the other treatments. With organic fertilizers added to SPF, the abundance of soil beneficial bacteria Bacillus, Paenibacillus, and Brevibacillus were highly improved, as well as the microbial function. It indicated that the SPF treatment could counteract the effects caused by mixing with clothianidin when compared to the SP treatment with only pesticide addition. Moreover, four bacterial genera including Dyella, Sphingomonas, Catenulispora, Mucilaginibacter, and Tumebacillus were significantly increased in the SPF and SP groups, which was reported to degrade clothianidin and could improve the soil health. The findings of the study provide insights into the interaction between the rhizosphere soil microbiome and a pesticide-fertilizer integration that may help improve application for pesticide-fertilizer in sugarcane fields.