bluuebunny/crossref_metadata_2025_split huggingface dataset:
Transcriptome response to temperature stress in the wolf spider Pardosa pseudoannulata (Araneae: Lycosidae)
Authors: Xiao Rong , Wang Liang , Cao Yingshuai , Zhang Guren 
Published: April 2016

AbstractThe wolf spider Pardosa pseudoannulata is a dominant predator in paddy ecosystem and an important biological control agent of rice pests. Temperature represents a primary factor influencing its biology and behavior, although the underlying molecular mechanisms remain unknown. To understand the response of P. pseudoannulata to temperature stress, we performed comparative transcriptome analyses of spider adults exposed to 10°C and 40°C for 12 h. We obtained 67,725 assembled unigenes, 21,765 of which were annotated in P. pseudoannulata transcriptome libraries, and identified 905 and 834 genes significantly up‐ or down‐regulated by temperature stress. Functional categorization revealed the differential regulation of transcription, signal transduction, and metabolism processes. Calcium signaling pathway and metabolic pathway involving respiratory chain components played important roles in adapting to low temperature, whereas at high temperature, oxidative phosphorylation and amino acid metabolism were critical. Differentially expressed ribosomal protein genes contributed to temperature stress adaptation, and heat shock genes were significantly up‐regulated. This study represents the first report of transcriptome identification related to the Araneae species in response to temperature stress. These results will greatly facilitate our understanding of the physiological and biochemical mechanisms of spiders in response to temperature stress.
The soil and plant biogeochemistry sampling design for The National Ecological Observatory Network
Authors: Hinckley Eve‐Lyn S. , Bonan Gordon B. , Bowen Gabriel J. , Colman Benjamin P. , Duffy Paul A. , Goodale Christine L. , Houlton Benjamin Z. , Marín‐Spiotta Erika , Ogle Kiona , Ollinger Scott V. , Paul Eldor A. , Vitousek Peter M. , Weathers Kathleen C. , Williams David G. 
Published: April 2016

AbstractHuman impacts on biogeochemical cycles are evident around the world, from changes to forest structure and function due to atmospheric deposition, to eutrophication of surface waters from agricultural effluent, and increasing concentrations of carbon dioxide (CO2) in the atmosphere. The National Ecological Observatory Network (NEON) will contribute to understanding human effects on biogeochemical cycles from local to continental scales. The broad NEON biogeochemistry measurement design focuses on measuring atmospheric deposition of reactive mineral compounds and CO2 fluxes, ecosystem carbon (C) and nutrient stocks, and surface water chemistry across 20 eco‐climatic domains within the United States for 30 yr. Herein, we present the rationale and plan for the ground‐based measurements of C and nutrients in soils and plants based on overarching or “high‐level” requirements agreed upon by the National Science Foundation and NEON. The resulting design incorporates early recommendations by expert review teams, as well as recent input from the larger natural sciences community that went into the formation and interpretation of the requirements, respectively. NEON's efforts will focus on a suite of data streams that will enable end‐users to study and predict changes to biogeochemical cycling and transfers within and across air, land, and water systems at regional to continental scales. At each NEON site, there will be an initial, one‐time effort to survey soil properties to 1 m (including soil texture, bulk density, pH, baseline chemistry) and vegetation community structure and diversity. A sampling program will follow, focused on capturing long‐term trends in soil C, nitrogen (N), and sulfur stocks, isotopic composition (of C and N), soil N transformation rates, phosphorus pools, and plant tissue chemistry and isotopic composition (of C and N). To this end, NEON will conduct extensive measurements of soils and plants within stratified random plots distributed across each site. The resulting data will be a new resource for members of the scientific community interested in addressing questions about long‐term changes in continental‐scale biogeochemical cycles, and is predicted to inspire further process‐based research.
Soil organic nitrogen endows invasive Solidago canadensis with greater advantages in low‐phosphorus conditions
Authors: Yu Hong‐Wei , Yang Jian‐Xia , Gao Yan , He Wei‐Ming 
Published: April 2016

AbstractAlthough the importance of soil nitrogen (N) and phosphorus (P) has long been recognized in plant nutrition, no study has addressed how soil organic N and P contribute to the success of invasive plants. To do so, we conducted two experiments in which invasive Solidago canadensis and native S. decurrens were either subjected to five amino acids or subjected to organic and inorganic N treatments (i.e., five amino acids and five ratios of nitrate to ammonium) under two P levels. In the first experiment, S. canadensis and S. decurrens grew taller when five amino acids were supplied than when no N was supplied, suggesting both species can use soil amino acids as N sources. In a second experiment, S. canadensis grew larger and taller than S. decurrens in the presence of organic and inorganic N, and organic N exhibited greater positive effects on the growth advantage of S. canadensis relative to S. decurrens than inorganic N; P levels influenced the effects of organic N on plant growth through changing biomass allocation and leaf chlorophyll. These results suggest that organic N and inorganic N may differentially contribute to the growth advantage of invasive species. Considering plant organic N economy is necessary to elucidate invasion mechanisms and expand plant strategies.
Local colonization‐extinction dynamics of a tree‐killing bark beetle during a large‐scale outbreak
Authors: Kärvemo S. , Johansson V. , Schroeder M. , Ranius T. 
Published: April 2016

AbstractForest pest insects may cause large‐scale tree growth reductions and tree mortality during outbreaks. The large‐scale development of outbreaks has frequently been studied, while the colonization‐extinction dynamics during outbreaks is less known. We study the colonization‐extinction dynamics of a severe tree‐killing bark beetle,Ips typographus, during an outbreak across a 130 000 ha forest landscape in southern Sweden. We recorded annual colonization and extinction events in 1 ha pixels across the landscape by helicopter surveys during three consecutive years, and modeled colonization and extinction probabilities based on focal pixel quality, local population size, connectivity to surrounding beetle populations, and tree composition in the surrounding landscape. The local populations had a high turnover; 81–93% of all occupied pixels were the result of colonizations in the same year and the annual extinction rates were 84–90%. The colonization probability increased and the extinction probability decreased with increasing spruce (host‐tree) volume in focal pixels and the connectivity. The fitted spatial scaling parameter of the connectivity measure suggested that the colonization probability was mainly affected by the number of surrounding occupied pixels within a few hundred meters. The colonization probability also decreased with increasing volume of birch (a nonhost) in the focal pixel, while the extinction probability decreased with increasing local population size. In conclusion, the local population size and quality of the focal pixel explained more of the colonization and extinction probability than the connectivity and composition of surrounding forest. The distribution of tree‐killing bark beetles during outbreaks can be patchy and highly dynamic. Two reasons for this are the increased probability of successful attacks when exceeding a critical attack density and the fragmented distribution of large spruce volumes throughout the forest landscape.
Rapidly shifting elevational distributions of passerine species parallel vegetation change in the subarctic
Authors: Mizel Jeremy D. , Schmidt Joshua H. , Mcintyre Carol L. , Roland Carl A. 
Published: April 2016

AbstractDespite predictions of poleward and upslope shifts in the distribution of breeding passerines under climate change, studies often report variable responses with some species shifting opposite of the expected direction and others showing range stability. While changes in climate could affect distribution directly, passerines show strong preferences for particular structural vegetation characteristics, suggesting that long‐term changes in vegetation may mediate a species' distributional response to climate, and consequently, may be responsible for the observed heterogeneity. We assessed changes in the elevational distribution and occupancy probability of 17 passerine species in Denali National Park, Alaska, from 1995 to 2013 across an elevational gradient containing multiple topographically defined ecotones (treeline and shrubline). An upward distributional shift was pervasive among shrub‐tundra species, corresponding with observed expansion of shrub cover at higher elevations. Forest‐associated passerines showed a weaker response as a group with some species showing range stability or retraction, while others exhibited modest expansions that were consistent with an advancing treeline ecotone. Denali's mean summer temperature increased significantly over the past century, but remained relatively stable over our study period, implying that longer term changes in climate indirectly influenced bird distribution through changes in woody vegetation. Further, heterogeneity in the response of forest‐associated species was consistent with a slower rate of forest development and expansion as compared with shrub colonization. Together, our results indicate that the elevational range dynamics of passerines may be related to species‐specific associations with different vegetation communities and variation across these vegetation communities in the timescale over which distributional change is occurring.
Effects of climate change on phenologies and distributions of bumble bees and the plants they visit
Authors: Pyke Graham H. , Thomson James D. , Inouye David W. , Miller Timothy J. 
Published: April 2016

AbstractSurveys of bumble bees and the plants they visit, carried out in 1974 near the Rocky Mountain Biological Laboratory in Colorado, were repeated in 2007, thus permitting the testing of hypotheses arising from observed climate change over the intervening 33‐yr period. As expected, given an increase in average air temperature with climate warming and a declining temperature with increasing elevation, there have been significant shifts toward higher elevation for queens or workers or both, for most bumble bee species, for bumble bee queens when species are combined, and for two focal plant species, with no significant downward shifts. However, contrary to our hypotheses, we failed to observe significant altitudinal changes for some bumble bee species and most plant species, and observed changes in elevation were often less than the upward shift of 317 m required to maintain average temperature. As expected, community flowering phenology shifted toward earlier in the season throughout our study area, but bumble bee phenology generally did not change, resulting in decreased synchrony between bees and plants. However, we were unable to confirm the narrower expectation that phenologies of bumble bee workers and community flowering coincided in 1974 but not in 2007. As expected, because of reduced synchrony between bumble bees and community flowering, bumble bee abundance was reduced in 2007 compared with 1974. Hence, climate change in our study area has apparently resulted primarily in reduced abundance and upward shift in distribution for bumble bees and shift toward earlier seasonality for plant flowering. Quantitative disagreements between climate change expectations and our observations warrant further investigation.
Species and functional trait turnover in response to broad‐scale change and an invasive species
Authors: Hewitt Judi E , Norkko Joanna , Kauppi Laura , Villnäs Anna , Norkko Alf 
Published: April 2016

AbstractWhile beta diversity has been implicated as a key factor in controlling resilience of communities to stressors, lack of long‐term data sets has limited the study of temporal dynamics of beta diversity. With a time series at two sites in excess of 40 yr, we investigated turnover of both species and functional traits in a system stressed by eutrophication and overfishing and undergoing climate change and invasion. The two sites, although located near to each other, differ in water depth (20 cf. 35 m), but both sites have displayed increased abundances of an invasive polychaete since 1990. We tested two hypotheses related to the effect of an invasive species; that taxa richness and turnover would decrease, and trait richness would increase post invasion and that trait turnover would increase between arrival and establishment of the invasive. Generally, we observed different dynamics at the two sites and responses not consistent with our hypotheses. We detected an increase in taxa richness at both sites and an increase in taxa turnover and number of traits at one site only. Trait turnover was higher prior to the invasion, although again only at one site. Disjunctive responses between species and trait turnover occurred, with the invader contributing in a nonrandom fashion to trait turnover. The lack of strong, consistent responses to the arrival and establishment of the invasive, and the decrease in trait turnover, suggests that effects of invasives are not only system‐ and species‐dependent, but also depend on community dynamics of the invaded site, in particular the assembly processes, and historical context.
Elemental concentrations in the frass of saproxylic insects suggest a role in micronutrient cycling
Authors: Chen Yi‐an , Forschler Brian T. 
Published: April 2016

AbstractConcentrations of 22 elements in pinewood were compared with that in frass produced by insects representing the following taxa:Reticulitermesspp. (Rhinotermitidae), Zootermopsis nevadensis(Termopsidae), Incisitermes snyderi(Kalotermitidae), Hylotrupesspp. (Cerambycidae),Heterobostrychusspp. (Bostrichidae), Lyctusspp. (Bostrichidae),and representatives of the family Ptinidae (formerly Anobiidae). Twenty elements (Al, B, Ba, Ca, Cd, Co, Cr, Cu, Fe, K, Mg, Mn, Mo, Na, Ni, P, Pb, Si, Sr, and Zn) were measured using inductively coupled plasma‐optical emission spectroscopy (ICP‐OES), whereas carbon, hydrogen, and nitrogen percentages were measured using aCHNautoanalyzer. Chromium was the only element present at a statistically lower concentration in all frass types compared to pinewood. A comparison of pinewood to frass from those taxa that fed on pine revealed thatReticulitermes frass contained significantly higher levels of 15 elements,Zootermopsis10, Ptinidae 5,Incisitermes4, andHylotrupes 1. OnlyIncisitermesfrass showed a significantly higher percent carbon than pinewood andReticulitermes,Zootermopsis, and Ptinidae showed significantly higher percent nitrogen. Examination of percent approximate digestibility (PAD) indicated thatReticulitermesfrass had 14 elements that were ≥200% more concentrated than found in pinewood, whereasZootermopsishad 6,Lyctus5, ptinid 4,HylotrupesandHeterobostrychus3, andIncisitermesnone. This survey of elements in frass indicates that saproxylic insects are, for the most part, not sequestrating but rather recycling (releasing) the store of micronutrients in wood biomass, with the greatest potential contribution to soil nutrient cycles attributable to subterranean termites.
Lake Baikal amphipods under climate change: thermal constraints and ecological consequences
Authors: Jakob Lena , Axenov‐Gribanov Denis V. , Gurkov Anton N. , Ginzburg Michael , Bedulina Daria S. , Timofeyev Maxim A. , Luckenbach Till , Lucassen Magnus , Sartoris Franz J. , Pörtner Hans‐O. 
Published: April 2016

AbstractLake Baikal, the world's most voluminous freshwater lake, has experienced unprecedented warming during the last decades. A uniquely diverse amphipod fauna inhabits the littoral zone and can serve as a model system to identify the role of thermal tolerance under climate change. This study aimed to identify sublethal thermal constraints in two of the most abundant endemic Baikal amphipods, Eulimnogammarus verrucosus and Eulimnogammarus cyaneus, and Gammarus lacustris, a ubiquitous gammarid of the Holarctic. As the latter is only found in some shallow isolated bays of the lake, we further addressed the question whether rising temperatures could promote the widespread invasion of this non‐endemic species into the littoral zone. Animals were exposed to gradual temperature increases (4 week, 0.8 °C/d; 24 h, 1 °C/h) starting from the reported annual mean temperature of the Baikal littoral (6 °C). Within the framework of oxygen‐ and capacity‐limited thermal tolerance (OCLTT), we used a nonlinear regression approach to determine the points at which the changing temperature‐dependence of relevant physiological processes indicates the onset of limitation. Limitations in ventilation representing the first limits of thermal tolerance (pejus (= “getting worse”) temperatures (Tp)) were recorded at 10.6 (95% confidence interval; 9.5, 11.7), 19.1 (17.9, 20.2), and 21.1 (19.8, 22.4) °C in E. verrucosus, E. cyaneus, and G. lacustris, respectively. Field observations revealed that E. verrucosus retreated from the upper littoral to deeper and cooler waters once its Tp was surpassed, identifying Tp as the ecological thermal boundary. Constraints in oxygen consumption at higher than critical temperatures (Tc) led to an exponential increase in mortality in all species. Exposure to short‐term warming resulted in higher threshold values, consistent with a time dependence of thermal tolerance. In conclusion, species‐specific limits to oxygen supply capacity are likely key in the onset of constraining (beyond pejus) and then life‐threatening (beyond critical) conditions. Ecological consequences of these limits are mediated through behavioral plasticity in E. verrucosus. However, similar upper thermal limits in E. cyaneus (endemic, Baikal) and G. lacustris (ubiquitous, Holarctic) indicate that the potential invader G. lacustris would not necessarily benefit from rising temperatures. Secondary effects of increasing temperatures remain to be investigated.
Phylogenetic clustering of fungal communities in human‐disturbed streams
Authors: Mykrä H. , Tolkkinen M. , Markkola A. M. , Pirttilä A.‐M. , Muotka T. 
Published: April 2016

AbstractPhylogenetic community structure is increasingly used to examine community assembly, but the influence of anthropogenic disturbance on phylogenetic community structure remains little explored. We examined how land‐use disturbance (forestry and agriculture) and naturally harsh environmental conditions (geologically driven acidity) affect the phylogenetic diversity of stream fungi. Using DNA from decomposing alder leaves, we calculated phylogenetic distances among fungal operational taxonomic units (OTUs). Closely related OTUs co‐occurred more often than expected by chance, but partitioning the relationship between phylogeny and niche differences showed evidence for niche conservatism only at short phylogenetic distances. Communities in human‐disturbed streams were phylogenetically clustered, whereas they were over‐dispersed in circumneutral near‐pristine streams. OTU richness did not decrease with disturbance; instead, some fungal taxa were replaced by closely related, more tolerant taxa. Fungal communities in naturally acidic reference streams also showed a tendency toward phylogenetic clustering, although much less so than in disturbed streams. Our results indicate different coexistence mechanisms in different environmental settings and a strong role for anthropogenic disturbance as a selective filter shaping the phylogenetic structure of instream fungal communities. The effects of human disturbances on the phylogenetic community structure of fungi occurred independently of taxonomic structure, suggesting utility of phylogenetic approaches to bioassessment.
Cumulative effects of an herbivorous ecosystem engineer in a heterogeneous landscape
Authors: Parsons Mitchell A. , Barkley Tela C. , Rachlow Janet L. , Johnson‐Maynard Jodi L. , Johnson Timothy R. , Milling Charlotte R. , Hammel John E. , Leslie Ian 
Published: April 2016

AbstractForaging by herbivores alters individual plants and vegetation communities directly, and engineering behaviors such as bioturbation (digging and turning soil) and biodeposition (deposition of feces and urine) can affect soils and physical properties that indirectly influence vegetation and other organisms. Patchy environments often concentrate the activities of animals, potentially increasing the magnitude of their impacts on the vegetative community over time. To evaluate the potential for herbivorous engineers to enhance existing heterogeneity, we quantified the direct and indirect effects of a burrowing herbivore, the pygmy rabbit (Brachylagus idahoensis), on soil and vegetation in the sagebrush steppe ecosystem of the western United States, and we evaluated whether the effects were related to duration of occupancy by rabbits. Mounded microtopography (i.e., mima mounds) creates distinct resource islands with relatively tall and dense sagebrush shrubs where pygmy rabbits concentrate burrowing and foraging activities. We quantified soil and vegetation characteristics on mima mounds occupied by rabbits for 1–12 yr and on unoccupied mounds. We expected that browsing would negatively influence slow growing sagebrush shrubs, but that digging and biodeposition would enhance soil nutrients and water infiltration. In addition, we hypothesized that the net effect on sagebrush reproduction would be positive because indirect effects on soil would enhance seed production by mature sagebrush and seedling growth, and because bioturbation would increase seed retention and germination. Pygmy rabbit occupancy had significant cumulative effects on both soil and vegetation properties on occupied mima mounds. Over time, browsing reduced sagebrush canopy cover and percent of individual shrubs that were alive. Soil properties were less influenced by the duration of occupancy of mima mounds than by the localized spatial influence of burrowing; elevated nitrogen levels were associated with burrow entrances. Two measures of sagebrush reproduction (seedling recruitment and inflorescence biomass) increased with duration of burrow occupancy, suggesting that over longer time frames pygmy rabbits enhanced reproduction and recruitment of sagebrush shrubs. Our data demonstrate multiple pathways by which an herbivorous engineer can influence habitat heterogeneity, and they suggest that although pygmy rabbits are inconspicuous on the landscape, the species might play an important role in maintaining and augmenting heterogeneity in the sagebrush steppe.
Acyliridium(III) Complexes with PCN Terdentate Ligands Including Imino‐ or Iminium‐Acyl Moieties or Formation of Hydrido from Hydroxyl
Authors: Zumeta Itziar , Mendicute‐Fierro Claudio , Rodríguez‐Diéguez Antonio , Seco José M. , Garralda María A. 
Published: April 2016

AbstractInvited for the cover of this issue is the group of María A. Garralda at Universidad del País Vasco, San Sebastián, Spain. The cover image shows an anionic dihydridoiridium species formed in methanol from a dihydridoirida‐β‐diketone and hydrogen release from the dihydrido species upon addition of 2‐aminoalkylpyridines to the solution. Hydrogen is transferred from hydroxyl in the solvent to iridium to afford the final hydridoaminodiacyl species.