Testing for linearity

linearitytesting

Heterosternuta sulphuria (Coloptera: Dytiscidae) Occurence in the Sulphur Springs Headwater System and in Buffalo National River Tributaries (Arkansas, USA): Current Distribution, Habitat Conditions, and Biomonitoring Framework

Heterosternuta sulphuria is an endemic aquatic species of concern in Arkansas, with a priority score of 80 out of 100 and a conservation rank of S1and G1. A need of the Arkansas Wildlife Action Plan (AWAP) was to obtain baseline information on distribution and population status of H. sulphuria. Here, we report new H. sulphuria records for 39 sites across 10 counties in the Ozark Highlands and Boston Mountain ecoregions and a determined habitat type of shallow margins and small bedrock pools of perennial streams and spring seeps. Few habitat patches were observed per site because detection was typically rapid and (unconfirmed) field identifications were possible because of the unique coloration of the pronotum, therefore only a small portion of the total available habitat was surveyed. We conclude that from our surveys and information gathered from other sources that in Arkansas H. sulphuria is probably ubiquitous among permanently wet aquatic habitats (primarily in upland headwater systems) throughout the Ozark Highlands and Boston Mountain ecoregions. Based on the number of occurrences, we recommend a downgrade of conservation status to S3 or S4. While some locations provide protection for current H. sulphuria populations (e.g., Buffalo National River, Hobbs State Park – Conservation Area, Sherfield Cave effluent stream, and USFS Richland Creek Wilderness), populations on unprotected lands in urban and agricultural settings probably have a much greater risk of population decline. A final determination of conservation status should consider several factors including dispersal capacity, population sizes, and genetic differentiation among populations. Furthermore, determining if existing H. sulphuria populations are isolated subpopulations or an interacting metapopulation and the habitat area required for population persistence are key for developing effective conservation actions. Monitoring existing populations should involve revisiting current H. sulphuria sites, and this is especially important for potentially fragmented populations in unprotected streams. Bioassessment programs could benefit from monitoring these easily observed populations that might positively relate to the overall physical and biological integrity of permanent Ozark streams and riparian corridors

Water Quality Monitoring and Constituent Load Estimation in the Upper Illinois River Watershed, 2009

The Arkansas Water Resources Center (AWRC) monitored water quality at eight sites in the Upper Illinois River Watershed (UIRW) during base flow conditions and storm events from July 1, 2009 through June 30, 2010. Water samples were collected manually with an alpha or Kemmerer style sampler and analyzed for nitrate-nitrogen (NO₃-N), sulfate (SO₄), chloride (Cl), soluble reactive phosphorus (SRP), total phosphorus (TP), dissolved ammonia (NH₃-N), total N (TN), total suspended solids (TSS), and turbidity. Physico-chemical parameters were measured in the field including pH, conductivity, water temperature, and dissolved oxygen concentration. The selected sites were at established discharge monitoring stations maintained by the US Geological Survey or AWRC, and constituent loads were determined using regression models between constituent concentrations, discharge, and seasonal factors to estimate daily loads, which were then summed to produce monthly and annual load estimates. The constituent loads and annual flow-weighted concentrations for the 2009 calendar year are summarized in the tables below, using the data collected in this study. The regression models were applied throughout the discharge record of the entire calendar year to estimate loads. Summary of calculate

Illinois River Volunteer Monitoring

Understanding how water quality conditions change along a land use gradient and over time is important for sustainable watershed management. Therefore, a volunteer monitoring program was created to measure water chemistry at 37 established sites within the Upper Illinois River Watershed and to evaluate changes in water chemistry over the past 15 years. The Illinois River Watershed Partnership (IRWP), a non‐profit organization subcontracted with the Arkansas Water Resources Center at the University of Arkansas, to manage the volunteer monitoring project, train volunteers to collect samples following EPA approved methods, and to analyze the collected samples. The AWRC trained 27 volunteers to collect water samples at 37 sites that were previously sampled in 1993 and 1994. Samples were collected during baseflow conditions during September and December 2008 and February and May 2009 and analyzed for soluble reactive phosphorus, nitrate‐nitrogen, sulfate, chloride, fluoride, total phosphorus, total nitrogen, total suspended solids, and turbidity. Geomean concentrations were calculated and compared to the concentrations observed during the 1993‐1994 study. Overall, total phosphorus and soluble reactive phosphorus concentrations significantly increased at 14% and 11% of the sampled sites, respectively, between the previous and current studies, while respective concentrations significantly decreased at 8% and 16% of sampled sites. The greatest reductions in phosphorus concentrations occurred at sites downstream of effluent discharges, and both total phosphorus and soluble reactive phoshporus concentrations were positevely correlated to pasture and urban land use within the catchment (R²= 0.11, P=0.045; R²= 0.16, P=0.015, respectively). Similarly,both total nitrogen and nitrate‐nitrogen concentrations were positvely correlated to urban and pasture land use (R²= 0.38, P \u3c 0.0001; R²=0.29, P=0.0006, respectively), and 5% and 14% of the sampled sites significantly increased in total nitrogen and nitrate nitrogen concentrations, respectively, between the two study periods. Overall, very few significant changes in water quality (i.e., water chemistry) were observed over the last 15 years; those changes that were most noticeable resulted from either improvements in the phosphorus mangement of waterwater treatment facilities or the introdiction of effluent discharge into a new receiving stream. Volunteer monitoring programs are an excellent way to promote environmental education and stewardship, and these programs can be useful in documenting changes in watershed conditions over time

Threshold autoregression with a near unit root

unit root;autoregressive models

Water Quality Sampling, Analysis and Annual Load Determinations for the Illinois River at Arkansas Highway 59 Bridge, 2008

The Arkansas Water Resources Center monitored water quality at the Illinois River at the Arkansas Highway 59 Bridge, just upstream from the Arkansas-Oklahoma state border during base flow and storm events from July 1, 2008 through June 30, 2009. Water samples were collected manually or with an auto-sampler and analyzed for nitrate-nitrogen, ammonia-nitrogen, total nitrogen, total phosphorus, soluble reactive phosphorus, sulfate, chloride and total suspended solids. The U.S. Geological Survey recorded instantaneous stage and discharge at the site, total annual discharge was 1,010,000,000 m³ , with 37% attributed to base flow and 63% attributed to storm flow. Loads were estimated using the mid-interval integration approach using continuous discharge (i.e., 30 min intervals) and measured concentration as applied to sampling intervals; the incremental loads were then summed to get annual loads for the 2008 calendar year. The constituent loads and annual flow-weighted concentrations for the 2008 calendar year are summarized in the table below, using data collected through this study (July through December 2008) plus data from the prior study year (January through June 2008)

Relationships between hornblende K-Ar ages, chemical composition and hydrogen isotopes, Connemara, western Ireland: evidence for a massive extinct hydrothermal system

Major element compositional analyses, K-Ar ages, deltaD parts per thousand and delta O-18 parts per thousand values for 30 zoned and unzoned hornblendes from Dalradian amphibolites and metagabbros. mostly in north Connemara are reported. Although the cooling ages are expected from previous U-Pb zircon studies to be c. 475-450 Ma the results obtained are from 556 +/- 6 to 410 +/- 9 Ma with an average of 470 Ma. Fluid movements. probably at 275 +/- 15 degreesC, i.e. much below Ar closure temperature for hornblende. erratically reset the ages, as is shown by a negative correlation of hornblende deltaD and age and a wide scatter of ages even within 2 m. The changes were implemented by deltaD exchange between fluid and hornblendes in which ionic porosity. Z, influenced the loss of Ar and possibly its gain from the fluid to give the excess Ar found in some samples. Z is controlled by hornblende chemical composition. High Mg, Si and Mg/Fe and low Fe, Al, Ti, Na and particularly low K, amphiboles giving low Z values retained Ar more firmly and gained Ar more readily than compositions which had higher Z values, which gave younger ages. These range down to c, 400 Ma. being the age of the intrusion of the Galway Granite suite that initiated the fluid circulation. The scatter of ages is a consequence of incomplete equilibration, mainly because of the slow deltaD exchange rate below 350 degreesC and partly because the fluid permeated erratically in different areas and down cracks of all kinds, promoting irregular Ar movement. The meteoric fluid circulated through Connemara. the Galway Granite and at least some of the contiguous Silurian sediments of the South Mayo trough. These overlying sediments may have contributed to the water circulated in north Connemara which was slightly less negative deltaD than in central Connemara. For hornblende K-Ar ages to be a reliable measure of times of uplift and cooling, they need to be demonstrated to be free from the influence of hot fluids by showing no correlation of age with deltaD

Parasites and non-fish predators of tilapia with particular reference to the sustainable management of fisheries of Lake Kainji Nigeria

The fisheries of Lake Kainji, Nigeria, experienced a boom year following impoundment, then decline post impoundment and now is in a period of stabilisation of the fish resources. Several reasons have been advanced on factors responsible for these changes, but two outstanding factors are those of nutritional status and fishing methods of the lake. Two important fish families however continue to dominate the lake fisheries in daily fisherman catches: Clupeidae and Cichlidae (tilapias). Recent studies have also shown that the dominance of the tilapias and clupeids is an important factor in the understanding of the stability of fisheries of Lake Kainji. One area which has remained undiscussed concerns the parasites and non-fish predators of tilapias which can affect the population dynamics of tilapias. This paper examines therefore some aspects of the fisheries of Lake Kainji and the potential roles that parasites and non-fish predators of tilapias can contribute in developing strategies for consideration in the sustainable management of the fisherie

Influence of Foliar Exposure, Adjuvants, and Rain-free Period on the Efficacy of Glyphosate for Torpedograss Control

The proportion of torpedograss tissue exposed to glyphosate at application rates of 0.28, 0.56, 1.12, 2.24, and 4.48 kg/ha affected control as measured by regrowth. The effect of tissue exposure was more pronounced as application rate decreased. This study suggests that higher rates of glyphosate need to be used during higher water levels, when less torpedograss tissue is exposed to herbicide spray and lower rates may be used during periods of low water levels. Addition of the water conditioning agent Quest (R) (0.25% v/v) to glyphosate spray mixtures diminished the influence of simulated rain events following glyphosate application. Twelve other adjuvants did not influence the effect of simulated rain events