The emblematic minnows of the North American Great Plains: A synthesis of threats and conservation opportunities

Anthropogenic changes to the Great Plains rivers of North America have had a large, negative effect on a reproductive guild of pelagic‐broadcast spawning (PBS) cyprinid fishes. The group is phylogenetically diverse, with multiple origins of the PBS mode. However, because of incomplete life‐history information, PBS designation often relies only on habitat and egg characteristics. We identified 17 known or candidate PBS fishes and systematically synthesized the literature on their biology and ecology in relation to major threats to persistence. Research output on an individual species was unrelated to conservation status, but positively correlated with breadth of distribution. The PBS species have opportunistic life‐history strategies and are typically short‐lived (generally 1–3 years) fishes. Many PBS species have truncated ranges showing declines in both distribution and abundance, especially those endemic to the Rio Grande catchment. Fundamental habitat associations are unknown for many species, particularly regarding seasonal shifts and early life stages. Critical thermal tolerances have been quantified for five PBS species and are generally >35°C. Turbidity and salinity changes are linked to responses at multiple life stages, but information is lacking on interactions between water quality and quantity. Hydrologic alteration appears to be a primary threat to PBS species, through complex interactions with landscape fragmentation, and habitat change. We highlight areas where scientific and management communities are lacking information and underline areas of potential conservation gain.     

Microbially available carbon in buried riparian soils in a glaciated landscape

Buried horizons and lenses in riparian soil profiles harbor large amounts of carbon relative to the surrounding soil horizons. Because these buried soil horizons, as well as deep surface horizons, frequently lie beneath the water table, their impact on nitrogen transport across the terrestrial–aquatic interface depends upon their frequency and spatial distribution, and upon the lability of associated organic matter. We collected samples of 51 soil horizons from 14 riparian zones Rhode Island, USA, where soil profiles are characterized by glacial outwash and alluvial deposits. These soil samples came from as deep as 2 m and ranged in carbon content from <1% to 44% in a buried O horizon 54–74 cm deep. We used these samples to: (1) determine the extent to which carbon in buried horizons, and deep surface horizons, is potentially microbially available; (2) identify spatial patterns of carbon mineralization associated with surface and buried horizons; and (3) evaluate likely relationships between soil horizon types, chemical characteristics and carbon mineralization. Carbon mineralization rates associated with buried horizons during anaerobic incubations ranged from 0.0001 to 0.0175 μmol C kg soil^?1 s^?1 and correlated positively with microbial biomass (R=0.89, P<0.0001, n=21). Excluding surface O horizons from the analysis, carbon mineralization varied systematically with horizon type (surface A, buried A, buried O, lenses, A/C, B, C) (P<0.05) but not with depth or depth x horizon interaction (overall R²=0.59, P<0.0005, n=47). In contrast to this result and to most published data sets, ¹³C-to-¹²C and ¹⁵N-to-¹⁴N ratios of organic matter declined with depth (¹³C?26.9 to ?29.3 per mil, ¹⁵N+5.6 to ?0.8 per mil). The absence of a relationship between horizon depth and C availability suggests that carbon availability in these buried horizons may be determined by the abundance and quality of organic matter at the time of horizon formation or burial, rather than by duration since burial, and implies that subsurface microbial activity is largely disconnected from surface ecosystems. Our results contribute to the emerging view that buried horizons harbor microbially available C in quantities relevant to ecosystem processes, and suggest that buried C-rich soil horizons need to be incorporated into assessments of the depth of the biologically active zone in near-stream subsurface soils.     

Ethnobotanical investigations in the genus <Emphasis Type="Italic">Momordica</Emphasis> L. in the Southern Western Ghats of India

Western Ghats, one of the megadiversity hotspots, hold a rich treasure of diversity in Momordica L. comprising M. charantia var. muricata, M. charantia var. charantia, M. dioica and M. sahyadrica. Vernacular names of these species vary from place to place. Traditional uses of these species comprising food, medicinal and cosmetic, culinary preparations, vernacular names in local dialects and taboos and religious beliefs relating to their domestication and folk taxonomy are dealt with in this paper.     

n-3 Fatty acids, hypertension and risk of cognitive decline among older adults in the Atherosclerosis Risk in Communities (ARIC) study

OBJECTIVE: Recent research indicates that n-3 fatty acids can inhibit cognitive decline, perhaps differentially by hypertensive status. DESIGN: We tested these hypotheses in a prospective cohort study (the Atherosclerosis Risk in Communities). Dietary assessment using a food-frequency questionnaire and plasma fatty acid exposure by gas chromatography were completed in 1987-1989 (visit 1), while cognitive assessment with three screening tools--the Delayed Word Recall Test, the Digit Symbol Substitution Test of the Wechsler Adult Intelligence Scale-Revised and the Word Fluency Test (WFT)--was completed in 1990-1992 (visit 2) and 1996-1998 (visit 4). Regression calibration and simulation extrapolation were used to control for measurement error in dietary exposures. SETTING: Four US communities--Forsyth County (North Carolina), Jackson (Mississippi), suburbs of Minneapolis (Minnesota) and Washington County (Maryland). SUBJECTS: Men and women aged 50-65 years at visit 1 with complete dietary data (n = 7814); white men and women in same age group in the Minnesota field centre with complete plasma fatty acid data (n = 2251). RESULTS: Findings indicated that an increase of one standard deviation in dietary long-chain n-3 fatty acids (% of energy intake) and balancing long-chain n-3/n-6 decreased the risk of 6-year cognitive decline in verbal fluency with an odds ratio (95% confidence interval) of 0.79 (0.66-0.95) and 0.81 (0.68-0.96), respectively, among hypertensives. An interaction with hypertensive status was found for dietary long-chain n-3 fatty acids (g day-1) and WFT decline (likelihood ratio test, P = 0.06). This exposure in plasma cholesteryl esters was also protective against WFT decline, particularly among hypertensives (OR = 0.51, P < 0.05). CONCLUSION: One implication from our study is that diets rich in fatty acids of marine origin should be considered for middle-aged hypertensive subjects. To this end, randomised clinical trials are needed.     

Comparative Efficacies of Next-Generation Insecticides Against Yellow Stem Borer and Their Effects on Natural Enemies in Rice Ecosystem

The efficacies of some next-generation insecticides against the rice yellow stem borer(YSB),Scirpophaga incertulas(Walk.), and their compatibilities with natural enemies were investigated during 2014 and 2015. Three newer insecticides, chlorantraniliprole 0.4% G, dinotefuran 20% SG, and methoxyfenozide 24% SC, and two commonly used insecticides, carbufuran 5 G and quinalphos 25 EC,were evaluated in the field for their efficacies against YSB and their non-target effects on natural enemies.Application of chlorantraniliprole 0.4% G at 10.96 kg/hm^2 resulted in the greatest reduction in YSB infestation(deadhearts and whiteheads) and greatest increase of yield compared to the untreated control plots, followed by methoxyfenozide 24% SC at 0.41 L/hm^2, dinotefuran 20% SG at 0.15 kg/hm^2,carbufuran 5 G at 10.96 kg/hm^2, and quinalphos 25 EC at 1.50 L/hm^2. All the insecticides reduced the numbers of predators viz., lady bird beetles, wolf spiders, carabid beetles, earwigs, green mirid bugs, and damselflies. Numbers of adults of the egg parasitoids Trichogramma sp., Telenomus sp. and Tetrastichus sp. were significantly reduced in insecticide-treated plots compared to untreated control plots. In all field trials, the harmful effects of the five insecticides were in the following rank order(least harmful to most harmful): chlorantraniliprole 0.4% G, carbufuran 5 G, dinotefuran 20% SG, methoxyfenozide 24% SC,and quinalphos 25 EC. On the basis of reduction in YSB infestation, increase in grain yield, and compatibility with natural enemies, chlorantraniliprole 0.4% G was proved to be the best of all the insecticides for YSB management system, although the study suggested minimizing its retail price for enhancement of cost effectiveness in farmers' fields.     

Assessing the benefits and wider costs of different N fertilisers for grassland agriculture

Fertiliser nitrogen (N) is essential for maintaining agronomic outputs for our growing population. However, the societal, economic and environmental impacts of excess reactive N from fertiliser is rarely assessed. Here the agronomic, economic and environmental efficacy of three N-fertiliser sources, ammonium-nitrate (AN), urea (U), and inhibited-urea (IU; with NPBT) were evaluated at two grassland sites. Dry matter yield and herbage quality were measured at each silage-cut. Additionally, NH₃-N and N₂O-N losses were measured and used to calculate the effective N source cost and externality costs, which account for associated environmental and societal impacts. We found no effect of different N sources on yield or herbage quality. However, NH₃-N emissions were significantly reduced under the IU treatment, by 48–65%. No significant differences in cumulative N₂O emissions were observed. Incorporating externality costs increased fertiliser prices by 1.23–2.36, 6.51–16.4, and 3.17–4.17 times the original cost, for AN, U and IU, respectively, transforming U from the cheapest, to the most expensive of the N sources examined. However, with no apparent yield differences between N-fertiliser sources there is no economic incentive for the land-manager to use the more environmentally and socially acceptable option, unless externality costs are incorporated into fertiliser prices at the point of sale.