Multi-taxon environmental DNA analysis reveals distributions and pathways of Pelophylax nigromaculatus invasion in Iwamizawa, Hokkaido, Japan

The invasion of alien species is a major factor leading to the biodiversity crisis. Biological invasion is a major cause of biodiversity loss in the United States. The U.S. government is consistently paying more attention to invasive species now. On February 3, 1999, President Clinton signed an executive order(EO)-to coordinate a federal strategy to address the growing environmental and economic threat from invasive plants and animals that are not native to the United States. The President’s order directs federal agencies to use their authority to prevent the introduction of invasive species and to restore native species. The EO directs establishment of an Invasive Species Council and prescribes the duties of the Council and federal agencies. The National Strategy for Invasive Plant Management, supported by the U.S. Department of Agriculture and other departments, proposes three national goals: prevention and control of invasive species’ and restoration. This National Strategy provides three mechanisms: partnerships, education, and research for different groups and individuals. It requires a high level of cooperation and collaboration among them. Aggressive federal actions are already underway, including measures to prevent entry of invasive species, control and eradication of invasive species, outreach and education for the general public, and an increase in the budget for each fiscal year.

A total of 180 larval collection sites (e.g., rice paddies, marshes, ground pools, ponds, stream margins, and irrigation and drainage ditches) was surveyed within a 2 km radius from Warrior Base training area, 5 km south of Panmunjeom (Joint Security Area, demilitarized zone), Gyeonggi Province, Republic of Korea (ROK), from May through October, 2007 to characterize larval habitat distributions of members of the Anopheles Hyrcanus Group (An. sinensis, An. lesteri, An. pullus, An. belenrae, An. kleini, and An. sineroides). A total of 5,859 anopheline larvae was collected from 84.4% of the sites surveyed, of which 4,071 were identified to species by polymerase chain reaction (PCR) using the ribosomal DNA internal transcribed spacer 2 (rDNA ITS2). Anopheles sinensis (52.6%) was the most frequently collected, followed by An. kleini (29.4%), An. sineroides (9.8%), An. pullus (6.7%), An. belenrae (1.1%), and An. lesteri (0.5%). Anopheles pullus and An. kleini were collected in greater proportions in May and from May - July, respectively. Few An. sinensis were collected from May - June, but it was the predominant species collected by August, and accounted for >80% of all larvae from September - October. Anopheles kleini was found in all habitats sampled; however, it was collected most frequently in young growth rice paddies, while An. sinensis was collected more frequently in mature and post-harvest paddies. Anopheles pullus was associated with pre-cultivated rice paddies, including water-filled tire ruts left from the previous fall's harvest.

Detection of invasive freshwater fish species using environmental DNA survey

The current study was undertaken with the objective of estimating methane emission and carbon flux with modified management practices (mid season drainage, zero tillage and sulphate application) using DNDC model and calibration and validation of the model at field scale. Methane (CH4) and carbon dioxide (CO2), two greenhouse gases (GHG) linked to agricultural activities are key contributors to climate change caused by human activity. Crop management techniques such stubble manuring, puddling, sowing or transplanting, water management, and harvesting have a significant impact on the carbon exchange between rice fields and the atmosphere. Mid-season irrigation water pond draining stops the ongoing submergence. The research studies reported that mid-season drainage reduced CH4 emissions. Hence an experiment was conducted at Agricultural Research Station, Tamil Nadu Agricultural University, Bhavanisagar with an objective of identification of management practices which emits low level of methane gas from rice ecosystem using rice variety CO 50 as test crop and modified management practices and sulphate application as treatments. Biometric observations were recorded and methane emission was quantified at 15 days interval from transplanting to harvest. Ten clumps of rice plants were sampled and Photosynthetically Active Radiation (PAR) was recorded at 15 days interval. The DeNitrification-DeComposition (DNDC) model was run for the treatment conditions. The field observations revealed that methane emission was low (41%) in the treatment of mid-season drainage when compared to control. The combination of mid-season drainage as well as Blue Green Algae (BGA) + Methylotroph along with Recommended Dose of NPK (T7) application reduced the methane emission up to 48 per cent compared to control. The results generated from the DNDC model also revealed the similar results. The DNDC model captures the major impacts of water and N on GHG emissions from paddy cultivation. The analysis suggested that the model can be applied for studying the GHG related issues in rice cropping systems.

Effect of mid-season drainage on CH4 and N2O emission and grain yield in rice ecosystem: A meta-analysis

Biological invasions are increasing in frequency and the need to mitigate or control their effects is a major challenge to natural resource managers. Failure to control invasive species has been attributed to inadequate policies, resources or scientific knowledge. Often, natural resource managers with limited funds are tasked with the development of an invasive species control program without access to key decision-support information such as whether or not an invasive species will cause damage, and what the extent of that damage may be. Once damages are realized, knowing where to allocate resources and target control efforts is not straightforward. Here we present the history of invasive species policy development and management in a large, multi-jurisdictional and multi-use aquatic ecosystem. We present a science-based decision-support tool for on-the-ground aquatic invasive species (AIS) control to support the development of a sustainable control program. Lastly, we provide a set of recommendations for managers desiring to make an AIS control implementation plan based upon our development of novel invasive species research, policy and management in Lake Tahoe (USA). We find that a sustainable invasive species control program is possible when science, coordination and outreach are integrated.

Rice agriculture is both an important source of the potent greenhouse gas methane (CH4) and a bioaccumulator of cadmium (Cd), which is hazardous to human health. Avoiding flooding during rice production is effective for reducing CH4 emissions, but it increases rice Cd uptake. Although lime application decreases Cd concentration in rice grains, it is not clear whether combining appropriate water management with liming can simultaneously reduce CH4 emissions and Cd uptake in rice paddies. Thus, a pot experiment was performed to investigate the interactive effects of water management (F: continuous flooding, FDF: flooding - midseason drainage - flooding, FDI: flooding - midseason drainage - intermittent irrigation) and lime application on CH4 emissions and rice Cd uptake in an acid paddy soil spiked with Cd. Results showed that neither water management nor liming significantly affected grain yield. Overall, liming reduced CH4 emissions by 42.2%. Compared to F, the FDF and FDI treatments reduced CH4 emissions by 43.5% and 54.2%, respectively. Liming reduced CH4 emissions by 32.6% under F, but with a greater decrease of 48.6% and 52.7% under FDF and FDI, respectively. Overall, liming reduced rice Cd uptake by an average of 47.3%. Compared to FDI, F and FDF significantly reduced Cd uptake by 84.0% and 75.1%, respectively, but there was no significant difference between F and FDF. Liming did not significantly affect Cd uptake under F and FDF, whereas liming reduced Cd uptake by 55.9% under FDI. These results suggest that maintaining flooding following midseason drainage can help in reducing rice Cd uptake, though slightly promoting CH4 emissions. Therefore, we recommend FDF combined with liming to mitigate CH4 emissions without increasing rice Cd uptake in acid paddy soils.

Green manure application helps maintain soil fertility, reduce chemical fertilizer use, and carbon sequestration in the soil. Nevertheless, the application of organic matter in paddy fields induces CH4 and N2O emissions. Prolonging mid-season drainage reduces CH4 emissions in paddy fields. Therefore, the combined effects of green manure application and mid-season drainage prolongation on net greenhouse gas emission (NGHGE) were investigated. Four experimental treatments were set up over a 2-year period: conventional mid-season drainage with (CMG) and without (CM) green manure and prolonged (4 or 7 days) mid-season drainage with (PMG) and without (PM) green manure. Astragalus sinicus L. seeds were sown in autumn and incorporated before rice cultivation. No significant difference in annual CH4 and N2O emissions, heterotrophic respiration, and NGHGE between treatments were observed, indicating that green manure application and mid-season drainage prolongation did not influence NGHGE. CH4 flux decreased drastically in PM and PMG during mid-season drainage under the hot and dry weather conditions. However, increasing applied carbon increases NGHGE because of increased CH4 and Rh. Consequently, combination practice of mid-season drainage prolongation and green manure utilization can be acceptable without changing NGHGE while maintaining grain yield in rice paddy fields under organically managed rice paddy fields.

To estimate the succession and phylogenetic composition of the bacterial communities responsible for the decomposition of rice straw compost under flooded conditions during the cultivation period of paddy rice, denaturing gradient gel electrophoresis (DGGE) analyses targeting 16S rDNA and 16S rRNA, followed by sequencing were conducted in a Japanese paddy field. The DGGE bands of the bacterial communities in the rice straw compost were significantly more numerous in the DNA samples than in the RNA samples. Although the band number of the DNA samples was almost constant throughout the period, RNA samples showed fewer DGGE bands after mid-season drainage than before it. Thus, about 81% of the bacteria present in rice straw compost were considered to be metabolically “active” before mid-season drainage and about 62% after it. The changes in the DGGE patterns of bacterial DNA and RNA before and after mid-season drainage, respectively, were also revealed by cluster analysis and principal component analysis of the DGGE patterns. These results indicated that the bacterial communities of rice straw compost incorporated into flooded paddy fields changed gradually along with the decomposition, except for the period of mid-season drainage, but that they were influenced by mid-season drainage. Members of β-, γ- and δ-Proteobacteria, Cytophaga-Flavobacterium-Bacteroides (CFB) group, Chlorobia, Verrucomicrobia, Chloroflexi, Spirochaetes, Firmicutes (clostridia) and Actinobacteria were present during the decomposition of rice straw compost. Characteristic “active” bacteria among them were as follows: Clostridium, Acinetobacter (γ-Proteobacteria) and β-Proteobacteria before mid-season drainage, Flavobacterium, Chondromyces, Chlorflexi and δ-Proteobacteria after mid-season drainage, and Spirochaeta and myxobacteria throughout the period.

: The U.S. Air Force (USAF) proposes to implement a revised Integrated Natural Resources Management Plan (INRMP) at New Boston Air Force Station (NBAFS), New Hampshire. As directed five-year update to the existing INRMP. The INRMP identifies goals, objectives, and projects for natural resources management and focuses on seven topical areas: (1) threatened, endangered and rare species; (2) wetlands; (3) rare natural communities; (4) forest management; (5) invasive non-native plant species control; (6) outdoor recreation; and (7) unexploded ordnance (UXO) remediation. The proposed action would result primarily in small, localized, short-term adverse impacts, but overall long-term benefits, to the environment. Anticipated impacts include Localized minor short-term adverse air-quality (fugitive dust, engine exhaust, and smoke) and noise impacts resulting from prescribed burning, timber harvests, and recreation facility construction projects. No violations are expected of Federal and State ambient air quality standards for criteria pollutants. Localized minor short-term adverse impacts to soils (erosion, compaction) resulting from prescribed burning, timber harvests, and recreation facility construction projects. Localized minor short-term adverse impacts to surface water quality (increases in turbidity, sedimentation, peak flow) resulting from runoff of areas of prescribed burning timber harvests, and recreation facility construction projects. Minor improvements in water quality of restored areas resulting from wetland restoration activities and invasive species control. Minor short-term adverse impacts to ecological resources (vegetation destruction wildlife disturbance), but overall net long-term benefit, resulting from prescribed burning, timber harvest, recreation facility construction, wetland restoration, invasive species control, and projects involving capture, handling, and radiotelemetry of animals.

Tree regeneration in the threatened forest of Robinson Crusoe Island, Chile: The role of small-scale disturbances on microsite conditions and invasive species

Based on the concept of establishing a continuous water flow and material cycle in a watershed, it is important to connect an irrigation canal system from the river to the drainage canal system and back to the former river. Even if biomass increases only in the drainage canal, the effect is limited. To enrich biodiversity in paddy fields, year-round water flows and natural materials in canal beds are important. However, information on the water volume that contributes to the environment and conserves paddy ecosystems is extremely limited. Therefore, we must address the technical issues related to water flow. The purpose of this study is to show the ecological significance of connecting irrigation and drainage canals in a consolidated paddy field and provide a practical plan based on a field survey of fish distributions at four sites in a paddy field in Shimodate City (now Chikusei City), Ibaraki Prefecture, Japan. The sampling interval was one week during May 2002 to June 2003. The results were the following: (1) the ten species of fishes caught in the canals were classified into two groups, fishes living mainly in drainage canals, such as Misgurnus anguillicaudatus and Silurus asotus, and those living in both irrigation and drainage canals, such as Gnathopogon elongatus elongatus. (2) The first group of fishes are distributed in the drainage canal system and move to paddy fields to facilitate movements between these two areas and expand their spawning grounds and habitats. These fishes are called ‘drainage–paddy field fish.’ The second group of fishes are distributed in both the irrigation and drainage canal systems, and it is important that movement is facilitated between the irrigation and drainage canal systems, which would also habitat. These fishes are called ‘irrigation–drainage fish.’ (3) An effective way to attain both fish conservation and high productivity is to employ a shallow farm drain by using an underdrain system for subsurface drainage. The small difference in elevation between farm drain and paddy plot allows the first group of fishes to enter the shallow water in the paddy field, and the connection of the main canal and shallow farm drain through water flow allows the second group of fishes to move between the irrigation and drainage canals. (4) As a fish conservation measure that can be conducted immediately, the fish that exist in the irrigation canal in the irrigation season can be moved to the shallow farm drain from the main canal before stopping the water flow for irrigation.KeywordsDrainage canalFarmland consolidationFishIrrigation canalPaddy fieldShallow farm drain

Since the early 1980s, water management of rice paddies in China has changed substantially, with midseason drainage gradually replacing continuous flooding. This has provided an opportunity to estimate how a management alternative impacts greenhouse gas emissions at a large regional scale. We integrated a process‐based model, DNDC, with a GIS database of paddy area, soil properties, and management factors. We simulated soil carbon sequestration (or net CO2 emission) and CH4 and N2O emissions from China's rice paddies (30 million ha), based on 1990 climate and management conditions, with two water management scenarios: continuous flooding and midseason drainage. The results indicated that this change in water management has reduced aggregate CH4 emissions about 40%, or 5 Tg CH4 yr−1, roughly 5–10% of total global methane emissions from rice paddies. The mitigating effect of midseason drainage on CH4 flux was highly uneven across the country; the highest flux reductions (>200 kg CH4‐C ha−1 yr−1) were in Hainan, Sichuan, Hubei, and Guangdong provinces, with warmer weather and multiple‐cropping rice systems. The smallest flux reductions (<25 kg CH4‐C ha−1 yr−1) occurred in Tianjin, Hebei, Ningxia, Liaoning, and Gansu Provinces, with relatively cool weather and single cropping systems. Shifting water management from continuous flooding to midseason drainage increased N2O emissions from Chinese rice paddies by 0.15 Tg N yr−1 (∼50% increase). This offset a large fraction of the greenhouse gas radiative forcing benefit gained by the decrease in CH4 emissions. Midseason drainage‐induced N2O fluxes were high (>8.0 kg N/ha) in Jilin, Liaoning, Heilongjiang, and Xinjiang provinces, where the paddy soils contained relatively high organic matter. Shifting water management from continuous flooding to midseason drainage reduced total net CO2 emissions by 0.65 Tg CO2‐C yr−1, which made a relatively small contribution to the net climate impact due to the low radiative potential of CO2. The change in water management had very different effects on net greenhouse gas mitigation when implemented across climatic zones, soil types, or cropping systems. Maximum CH4 reductions and minimum N2O increases were obtained when the mid‐season draining was applied to rice paddies with warm weather, high soil clay content, and low soil organic matter content, for example, Sichuan, Hubei, Hunan, Guangdong, Guangxi, Anhui, and Jiangsu provinces, which have 60% of China's rice paddies and produce 65% of China's rice harvest.

Early detection before establishment and identification of key predators are time-honored strategies towards effective eradication or control of invasive species. The brown marmorated stink bug (BMSB), Halyomorpha halys, is a recent exotic pest of several important crops in North America and Europe. Resulting widespread applications of insecticides have countered years of careful integrated pest management and are leading to the resurgence of other agricultural pests. Environmental DNA (eDNA) has been used effectively to detect aquatic invasives. We developed a real-time PCR (qPCR) assay for BMSB in a conserved region of the ribosomal DNA interspacer 1 (ITS1). We validated this assay on worldwide populations of BMSB and tested its specificity and sensitivity against other US Pentatomidae species and on guano of big brown bat, Eptesicus fuscus, which we confirmed is a BMSB predator in New Jersey. We also detected BMSB DNA after rapid (and inexpensive) HotSHOT DNA extractions of soiled paper from cages briefly holding BMSB, as well as from discarded exuviae. Given the high sensitivity of our assay to BMSB environmental DNA (eDNA) in terrestrial samples, this tool should become a cost-effective approach for using eDNA to detect terrestrial invasive species and their key predators. © 2016 Society of Chemical Industry.

Sewage irrigation increased methane and nitrous oxide emissions from rice paddies in southeast China