A Guide to the Common Native and Exotic Thistles of South Dakota

This guide was compiled to provide an aid for the rapid identification of the more common pest and non-pest thistle species in South Dakota. Because of the great expense of managing and controlling invasive thistles in rangelands, pastures, and croplands, it is essential to be accurate in the identification of any species at hand. The recognition of native species not only helps maintain local biodiversity, but also prevents wasted effort, controls costs, and minimizes herbicide use and chemical pollution. It should be noted that native thistles are important both as floral resources for native pollinating insects and as seed sources for birds. To a certain degree, invasive thistle species are also important in these regards, but their negative impact to native communities outweighs their supplementary value. There are 11 species of plants in South Dakota commonly called thistle. This does not include sow thistle (Sonchus spp.) or Russian thistle (Salsola spp.), neither of which is closely related to true thistles. Six of these 11 are native species and are natural components of prairie, meadow, or woodland habitats. The remaining five are exotic species from Europe and Asia that were introduced to the U.S. The exotics are invasive weeds and have significant economic impact on crop and livestock production, native biological community stability, and recreation. This guide is useful for discriminating between the five native and five exotic species most commonly found in South Dakota

EFFECTS OF HERBICIDES AND GRAZING ON FLORISTIC QUALITY OF NATIVE TALLGRASS PASTURES IN EASTERN SOUTH DAKOTA AND SOUTHWESTERN MINNESOTA

Historic herbicide use and grazing have influenced natural diversity and quality of native pasturelands in the Great Plains. Floristic quality assessments are useful to assist agencies in prioritizing conservation practices to enhance native grasslands. The objective of this study was to determine the effects of past land-use practices on the floristic quality of remnant native pastures in eastern South Dakota and southwestern Minnesota. Floristic quality assessments were conducted on 30 native pastures and categorized by past management practices (herbicide application and grazing intensity). Mean coefficient of conservatism (C) and floristic quality index (FQI) were calculated for each site~Results showed that increased herbicide use and grazing intensity resulted in a lower species richness, forb C ,and FQI. However, grass and grasslike plants were minimally affected. Pastures that were infrequently sprayed with herbicides and lightly grazed consistently had the highest species richness, C ,and FQI. Pastures with no grazing produced similar values to those with moderate grazing. Pastures managed as preserves or wildlife habitat areas had higher FQI than those managed for livestock grazing. The implications of this study should further help ecologists and managers understand the positive and negative effects of grazing practices and herbicide application on tallgrass prairie remnants

EFFECTS OF HERBICIDES AND GRAZING ON FLORISTIC QUALITY OF NATIVE TALLGRASS PASTURES IN EASTERN SOUTH DAKOTA AND SOUTHWESTERN MINNESOTA

Historic herbicide use and grazing have influenced natural diversity and quality of native pasturelands in the Great Plains. Floristic quality assessments are useful to assist agencies in prioritizing conservation practices to enhance native grasslands. The objective of this study was to determine the effects of past land-use practices on the floristic quality of remnant native pastures in eastern South Dakota and southwestern Minnesota. Floristic quality assessments were conducted on 30 native pastures and categorized by past management practices (herbicide application and grazing intensity). Mean coefficient of conservatism (C) and floristic quality index (FQI) were calculated for each site~Results showed that increased herbicide use and grazing intensity resulted in a lower species richness, forb C ,and FQI. However, grass and grasslike plants were minimally affected. Pastures that were infrequently sprayed with herbicides and lightly grazed consistently had the highest species richness, C ,and FQI. Pastures with no grazing produced similar values to those with moderate grazing. Pastures managed as preserves or wildlife habitat areas had higher FQI than those managed for livestock grazing. The implications of this study should further help ecologists and managers understand the positive and negative effects of grazing practices and herbicide application on tallgrass prairie remnants

Grassy Weeds

Grassy weeds are a problem in all field crops. They must be identified at early stages of growth so they can be controlled before crop yields are seriously threatened. Control measures are not the same for all grassy weeds, so accurate seedling identification is essential. Most grassy weeds and grain crops look very much alike in the seedling stages. However, if you look closely (a small hand lens helps) you can pick out the unique vegetative characteristics of each weed and crop seedling. Rudiments of the seed coat are helpful to distinguish crop seedlings from grassy weeds; however, seed coat is often absent. The vegetative characteristics that identify grasses are labeled in Fig 1. A summary of the unique characteristics of each species I given in Table 1

Children\u27s Time Outdoors: Results from a National Survey

Abstract In the past decade, much has been said and written about American children’s declining outdoor leisure time. These claims are confounded by the absence of a baseline for detecting trends in children’s activities and time spent outdoors. The USDA Forest Service initiated a general population telephone survey, the National Kids Survey, to address this issue. This paper summarizes data collected during the first phase of this project (2007-2009). Results suggest that most children across all demographic groups are spending a substantial amount of time outdoors daily. Interaction with the natural environment varies as playing/hanging out, physical activities, and technology-centered activities appear to be more popular than nature-based activities. Future research efforts should build on these initial data and continue to monitor children’s outdoor activities patterns across diverse populations

KIR channel activation contributes to onset and steady-state exercise hyperemia in humans

We tested the hypothesis that activation of inwardly rectifying potassium (KIR) channels and Na+-K+-ATPase, two pathways that lead to hyperpolarization of vascular cells, contributes to both the onset and steady-state hyperemic response to exercise. We also determined whether after inhibiting these pathways nitric oxide (NO) and prostaglandins (PGs) are involved in the hyperemic response. Forearm blood flow (FBF; Doppler ultrasound) was determined during rhythmic handgrip exercise at 10% maximal voluntary contraction for 5 min in the following conditions: control [saline; trial 1 (T1)]; with combined inhibition of KIR channels and Na+-K+-ATPase alone [via barium chloride (BaCl2) and ouabain, respectively; trial 2(T2)]; and with additional combined nitric oxide synthase (NG-monomethyl-l-arginine) and cyclooxygenase inhibition [ketorolac; trial 3 (T3)]. In T2, the total hyperemic responses were attenuated ∼50% from control (P \u3c 0.05) at exercise onset, and there was minimal further effect in T3 (protocol 1; n= 11). In protocol 2 (n = 8), steady-state FBF was significantly reduced during T2 vs. T1 (133 ± 15 vs. 167 ± 17 ml/min; Δ from control: −20 ± 3%; P \u3c 0.05) and further reduced during T3 (120 ± 15 ml/min; −29 ± 3%; P \u3c 0.05 vs. T2). In protocol 3 (n = 8), BaCl2 alone reduced FBF during onset (∼50%) and steady-state exercise (∼30%) as observed in protocols 1 and 2, respectively, and addition of ouabain had no further impact. Our data implicate activation of KIR channels as a novel contributing pathway to exercise hyperemia in humans

Visitor Support for Recreation Fees in Georgia State Parks

Abstract Public land managers are experiencing increasing pressure to create parks that are self-sustaining. Recreation fees can help managers achieve this goal, but tradeoffs associated with fees often produce undesired consequences (i.e., declining visitation) that warrant further investigation. This study used intercept surveys (n = 1049) to examine support for recreation fees among visitors to Georgia state parks. Participants were evenly split regarding their willingness to pay to enter state parks, with a mean willing to pay increase about $2 above the current$5 parking fee. Proposed fee increases negatively affected projected visitation among all groups, particularly low-income visitors. Place attachment ratings were the strongest predictor of support for fees. Results suggest that, to accommodate a diverse clientele, managers could work on strengthening visitors’ attachment to and reliance upon state parks while developing flexible pricing schemes that appeal to a range of potential users

Reactive Hyperemia Occurs Via Activation of Inwardly Rectifying Potassium Channels and Na+/K+-ATPase in Humans

Rationale: Reactive hyperemia (RH) in the forearm circulation is an important marker of cardiovascular health, yet the underlying vasodilator signaling pathways are controversial and thus remain unclear. Objective: We hypothesized that RH occurs via activation of inwardly rectifying potassium (KIR) channels and Na+/K+-ATPase and is largely independent of the combined production of the endothelial autocoids nitric oxide (NO) and prostaglandins in young healthy humans. Methods and Results: In 24 (23±1 years) subjects, we performed RH trials by measuring forearm blood flow (FBF; venous occlusion plethysmography) after 5 minutes of arterial occlusion. In protocol 1, we studied 2 groups of 8 subjects and assessed RH in the following conditions. For group 1, we studied control (saline), KIR channel inhibition (BaCl2), combined inhibition of KIR channels and Na+/K+-ATPase (BaCl2 and ouabain, respectively), and combined inhibition of KIR channels, Na+/K+-ATPase, NO, and prostaglandins (BaCl2, ouabain, L-NMMA [NG-monomethyl-L-arginine] and ketorolac, respectively). Group 2 received ouabain rather than BaCl2 in the second trial. In protocol 2 (n=8), the following 3 RH trials were performed: control; L-NMMA plus ketorolac; and L-NMMA plus ketorolac plus BaCl2 plus ouabain. All infusions were intra-arterial (brachial). Compared with control, BaCl2 significantly reduced peak FBF (−50±6%; P2 (−61±3%) and ouabain (−44±12%) alone, and this effect was enhanced when combined (−87±4%), nearly abolishing RH. L-NMMA plus ketorolac did not impact total RH FBF before or after administration of BaCl2 plus ouabain. Conclusions: Activation of KIR channels is the primary determinant of peak RH, whereas activation of both KIR channels and Na+/K+-ATPase explains nearly all of the total (AUC) RH in humans

Impaired Peripheral Vasodilation during Graded Systemic Hypoxia in Healthy Older Adults: Role of the Sympathoadrenal System

Systemic hypoxia is a physiological and pathophysiological stress that activates the sympathoadrenal system and, in young adults, leads to peripheral vasodilation. We tested the hypothesis that peripheral vasodilation to graded systemic hypoxia is impaired in older healthy adults and that this age-associated impairment is due to attenuated β-adrenergic mediated vasodilation and elevated α-adrenergic vasoconstriction. Forearm blood flow was measured (Doppler ultrasound) and vascular conductance (FVC) was calculated in 12 young (24±1 yrs) and 10 older (63±2 yrs) adults to determine the local dilatory responses to graded hypoxia (90, 85, and 80% O2 saturations) in control conditions, following local intra-arterial blockade of β-receptors (propranolol), and combined blockade of α+β receptors (phentolamine + propranolol). Under control conditions, older adults exhibited impaired vasodilation to hypoxia compared with young at all levels of hypoxia (peak ΔFVC at 80% SpO2 = 4±6 vs. 35±8%; P\u3c0.01). During β-blockade, older adults actively constricted at 85 and 80% SpO2 (peak ΔFVC at 80% SpO2= -13±6%; P\u3c0.05 vs. control) whereas the response in the young was not significantly impacted (peak ΔFVC = 28±8%). Combined α+β blockade increased the dilatory response to hypoxia in young adults, however older adults failed to significantly vasodilate (peak ΔFVC at 80% SpO2= 12±11% vs. 58±11%; P\u3c0.05). Our findings indicate that peripheral vasodilation to graded systemic hypoxia is significantly impaired in older adults which cannot be fully explained by altered sympathoadrenal control of vascular tone. Thus, the impairment in hypoxic vasodilation is likely due to attenuated local vasodilatory and/or augmented vasoconstrictor signaling with age