Impact of land use and management practices on soil nematode communities of Machair, a low-input calcareous ecosystem of conservation importance.

Machair is a vulnerable low-lying coastal ecosystem with internationally recognised conservation importance. It is characterised by wind-blown calcareous shell-sand soils that support a patchwork of low-input land-use types including species rich grasslands and small-scale arable production. In contrast to numerous above-ground studies, few below-ground studies have been made on the Machair. Thus, a knowledge gap exists, and no baseline data is available to determine the impact, if any, of fundamental changes in Machair land management practices such as a move from traditional rotational to permanent grazing, and increased use of inorganic fertiliser. To address this knowledge deficit, we assessed the impact of different agronomic management practices (cropped, fallow and grasslands) on the structure of soil nematode communities over a two-year period along a geographically limited north-south gradient of coastal Machair of the Outer Hebrides archipelago. Land use followed by season were the main drivers of nematode communities from Machair soils. Functionally, nematode communities from grassland were typically distinct from cropped or fallow communities driven primarily by differential contributions to the overall nematode community by the dominant bacterial-feeding nematodes. Temporally, nematode communities sampled in spring and autumn were distinct.

Nitrogen fertilizer and Amorpha fruticosa leguminous shrub diversely affect the diazotroph communities in an artificial forage grassland.

Soil diazotrophs have been known to be essential in biological nitrogen (N) fixation, which contributes to the sustainability of agricultural ecosystems. However, there remains an inadequacy of research on the effects of different N inputs from N fertilization and from symbiotic N fixation associated with legumes on the diazotroph communities in agricultural ecosystems. Hence, we investigated the variations in diazotroph abundance and community composition as well as the soil properties with different N inputs in the Guimu-1 hybrid elephant grass cultivation on karst soils in China. We conducted six different N treatments: control, Amorpha fruticosa planting at a spacing of 1.5 × 2 m (AFD1), A. fruticosa planting at a spacing of 1 × 2 m (AFD2), N fertilization (N), A. fruticosa planting at a spacing of 1.5 × 2 m with N fertilization (AFD1N), and A. fruticosa planting at a spacing of 1 × 2 m with N fertilization (AFD2N). Our results showed that the interaction between sampling time and N fertilization significantly affected the diazotroph abundance. In July, the diazotroph abundance significantly decreased in the N fertilization treatments: N, AFD1N, and AFD2N, compared to that in the control. The richness and Chao1 estimator of diazotrophs significantly increased in AFD2N and AFD1 correspondingly in December and July, relative to those in the control. Co-occurrence networks showed species-species interactions with high negative correlations that occurred more in the control than in the N input plots. The N input from N fertilization and legume planting directly increased the ammonium N and nitrate N and consequently affected the dissolved organic N and pH of the soil, thereby altering the diazotroph abundance and richness. Our findings demonstrated that both N fertilization and legumes could reduce the interspecific competition among diazotroph species by providing greater N availability in the forage grass.

Internet of Things to network smart devices for ecosystem monitoring.

Smart, real-time, low-cost, and distributed ecosystem monitoring is essential for understanding and managing rapidly changing ecosystems. However, new techniques in the big data era have rarely been introduced into operational ecosystem monitoring, particularly for fragile ecosystems in remote areas. We introduce the Internet of Things (IoT) techniques to establish a prototype ecosystem monitoring system by developing innovative smart devices and using IoT technologies for ecosystem monitoring in isolated environments. The developed smart devices include four categories: large-scale and nonintrusive instruments to measure evapotranspiration and soil moisture, in situ observing systems for CO2 and δ13C associated with soil respiration, portable and distributed devices for monitoring vegetation variables, and Bi-CMOS cameras and pressure trigger sensors for terrestrial vertebrate monitoring. These new devices outperform conventional devices and are connected to each other via wireless communication networks. The breakthroughs in the ecosystem monitoring IoT include new data loggers and long-distance wireless sensor network technology that supports the rapid transmission of data from devices to wireless networks. The applicability of this ecosystem monitoring IoT is verified in three fragile ecosystems, including a karst rocky desertification area, the National Park for Amur Tigers, and the oasis-desert ecotone in China. By integrating these devices and technologies with an ecosystem monitoring information system, a seamless data acquisition, transmission, processing, and application IoT is created. The establishment of this ecosystem monitoring IoT will serve as a new paradigm for ecosystem monitoring and therefore provide a platform for ecosystem management and decision making in the era of big data.

A whole-transcriptome approach to evaluate reference genes for quantitative diurnal gene expression studies under natural field conditions in Tamarix ramosissima leaves

Background: Tamarix ramosissima is a desert forest tree species that is widely distributed in the drought-stricken areas to sustain the fragile ecosystem. Owing to its wide usage in the desert restoration of Asia, it can be used as an ecophysiological model plant. To obtain reliable and accurate results, a set of reference genes should be screened before gene expression. However, up to date, systematical evaluation of reference genes has not been conducted in T. ramosissima. Results: In this study, we used eigenvalues derived from principal component analysis to identify stable expressed genes from 72,035 unigenes from diurnal transcriptomes under natural field conditions. With combined criteria of read counts above 900 and CV of FPKM below 0.3, a total of 7385 unigenes could be qualified as candidate reference genes in T. ramosissima. By using three statistical algorithm packages, geNorm, NormFinder, and BestKeeper, the stabilities of these novel reference genes were further compared with a panel of traditional reference genes. The expression patterns of three aquaporins (AQPs) suggested that at least UBQ (high expression), EIF4A2 (low expression), and GAPDH (moderate expression) could be qualified as ideal reference genes in both RT-PCR and RNA-seq analysis of T. ramosissima. Conclusions: This work will not only facilitate future studies on gene expression and functional analysis of genetic resources of desert plants but also improve our understanding of the molecular regulation of water transport in this plant, which could provide a new clue to further investigate the drought adaptation mechanism of desert plant species under harsh environments.

Notas sobre Chloraea undulata "Orquídea de Lima" y su registro en las lomas de Asia, Cañete, Perú

Chloraea undulata es una orquídea endémica del Perú. Originalmente colectada por Antonio Raimondi en el siglo XIX, fué reconocida como una especie característica de las lomas de Lima hasta mediados del siglo pasado. Desde entonces, la especie ha sido considerada desaparecida de las lomas costeras y especialmente del Cerro Amancaes, su localidad tipo, que hoy integra el casco urbano de la capital. En el presente trabajo, se documenta su presencia en las lomas de Asia 100 km al sur de Lima y se valora la importancia de este hallazgo para la conservación de la especie y su hábitat.

Chloraea undulata is an orchid endemic to Peru. Originally collected by Antonio Raimondi in XIX century, until first half of the last century it has been regarded as a species characteristic of the hills around Lima. The "Lima orchid" Chloraea undulata is considered to be in decline in the hills of Lima province, especially in the type localities of Cerro Amancaes and Cerro El Agustino where urban growth and expansion has been significant. In this paper its presence in the hills of Asia District, 100 km south of Lima, is documented, and we also analyzed the implications of this finding for the species conservation and their habitat.