Vegetation community changes in response to phragmites management at Times Beach, Buffalo, New York

Management of invasive phragmites (Phragmites australis [Cav.] Trin. Ex Steud.) in the United States has proven challenging over the last several decades. Various methods for control exist, but integrated approaches appear to have the most success. However, documentation of vegetation community–wide responses to these approaches remains limited. This study monitored plant community changes at Times Beach, New York, over a five-year period. In concert with mowing and thatch removal in all areas, the study evaluated two herbicides separately and together, representing three experimental treatment areas (TAs), for control efficacy by measuring plant community structure. Phragmites was targeted for treatments, avoiding native and nonproblematic non-native species when possible, to preserve beneficial habitat during phragmites control efforts. Monitoring results showed significant drops in phragmites relative cover, relative frequency, and importance values due to integrated management, regardless of herbicide treatment, with corresponding increases in these same values for native and other plant species. This suggests that prudent removal of phragmites is compatible with beneficial plant restorative efforts to maintain and improve habitat in infested areas.

Cushion Shrubs Encroach Subhumid Rangelands: Fertility Islands in Fragile Soils Along a Grazing Gradient in Patagonia

PurposeThis work assesses changes in soil and vegetation structure associated with grazing intensity (GI) in subhumid grasslands. We conducted the study in the Subandean district of Patagonia, Argentina. Non-degraded Subandean grass steppes have extremely erodible volcanic soils and are valuable grazing ranges. However, nowadays vast portions exhibit a heterogeneous cover that is mostly of cushions shrubs, with big eroded soil patches.MethodsWe selected four study sites along a GI gradient and one grazed-excluded site. Soils, vegetation cover and patches structure were characterised. We took soil samples beneath grass and shrub patches and their interpatches and in undisturbed spots. ResultsSoils in undisturbed spots had the highest chemical fertility. Soils in grazing areas showed high heterogeneity associated with plant life-form and GI. Results also showed that medium and fine sand particles remobilised from bare soil to vegetated patches. Total nitrogen and organic matter increased in the same direction. Grass cover decreased as GI increases, while shrubs cover and total richness increased, until a collapse at the highest intensity. Relative cover of cushion shrubs and bare soil grow steadily with GI. ConclusionsThe fertility island effect was associated with cushion shrubs. Grazing caused cushion shrub encroachment regardless of its intensity. Notwithstanding this, the same disturbance -grazing- which promoted cushions prevalence also favoured the collapse of fertile islands when reached to maximum intensity. Ecosystem services provision from a range management standpoint decreased. However, the increases in richness under moderate GI could represent an enhancement in system functionality.

The relative effect of altitude and aspect on saxicolous lichen communities at mountain summits from central-west of Argentina

The altitudinal patterns of lichen communities in altitudinal gradients are very variable. The changes that occur along the mountains depend on climatic factors but also on microsite variables such as substrate type and aspect. The effect of altitude and aspect on richness, cover and composition of saxicolous lichens communities along an elevation gradient in extra Andean mountains from the central-west of Argentina was studied. Rock outcrops on the north and south aspect of three mountain summits distributed between 2,500 and 4,500 m.a.s.l. were sampled. Lichen species present in a 20 × 20 cm square were identified and the relative cover was measured using digital photography. Richness, cover and composition were analyzed through linear models and multivariate analysis. Fifty-eight saxicolous lichen species were identified between the three sites. Richness and cover were maximum at middle altitude. Also compositional differences among communities of each mountain summit were found. Finally, the effect of the aspect was significant at lower altitudes for cover and composition.

Constructed Wetlands for Water Quality Improvement: A Synthesis on Nutrient Reduction from Agricultural Effluents

Excess nutrients from agricultural settings contribute to surface water and groundwater impairment. Constructed wetlands have been widely used for water quality protection in various agricultural systems. We used a synthesis approach to document the performance of constructed wetlands for nutrient removal from a range of landscapes and geographic regions with the following objectives: (1) review the current use of constructed wetlands in agricultural applications, (2) summarize the nutrient removal efficiency of constructed wetlands, and (3) identify the geographic usage and costs associated with constructed wetlands. We reviewed over 130 publications and reports to characterize nutrient removal performance for the following types of agricultural effluents: cropland surface and subsurface drainage, and wastewater from livestock production, greenhouse, aquaculture, and hydroponic systems. Data from the reviewed studies indicate that constructed wetlands are efficient in protecting water quality in agricultural production settings. However, differences in constructed wetland characteristics reported by the studies suggest that standards are needed to ensure nutrient removal goals are met based on wetland design. Researchers should consider including basic performance parameters for constructed wetlands in published reports, including influent and effluent concentrations, hydraulic retention time, hydraulic loading rate, watershed to treatment wetland ratios, and plant species and relative cover. Future studies are needed to explore cost-benefit analyses to assess the feasibility and potential promotion of wetland incentive programs in various geographic regions and watershed nonpoint-source pollution goals for using these systems in agricultural settings. Keywords: Agricultural wastewater, Agricultural water quality, Aquaculture, Cropland runoff, Greenhouse, Hydroponic, Livestock, Review, Subsurface, Treatment wetland.

ANALISIS STRUKTUR KOMUNITAS MANGROVE DI KAWASAN SEKITAR PT. CONCH KABUPATEN BOLAANG MONGONDOW

This research was conducted for four months of April-July 2020. The purpose of this study was to determine species density, species relative density, species frequency, species relative frequency, species cover, species relative cover, index of the importance of mangrove species in the area around PT. Conch Lolak District, Bolaang Mongondow Regency, North Sulawesi Province. This research was conducted for four months of April-July 2020. The method used was a quadratic plot of 6 stations. Data collection at each station was made with a plot size of 10 × 10 m2 to measure the diameter of a tree at breast height (DBH), which has a minimum trunk circumference of 16 cm. The results showed that there were five types of mangroves, namely R. apiculata, R. mucronata, B. gymnorhiza, S. alba, and X. granatum. The highest relative density of species at station 2, namely R. mucronate 62.96%, while the lowest value at station 3, namely R. mucronata 8.77%, the highest relative frequency value at station 4, namely R. mucronata 33.33%, whereas the lowest value was at station 5, namely B. gymnorhiza 25.00%, the highest relative closure value was at station 5, namely R. mucronata 30.91%, while the lowest was at station 2, namely R. apiculata 12.88%, and the important value index the highest was at station 3, namely R. apiculata 138.09% and the lowest value was at station 5, namely X. granatum 35.05%.Kata Kunci: Mangrove, Structure in areas around PT. Conch. Conch, Rhizopora Abstrak Penelitian ini dilakukan selama 4 bulan April-Juli 2020. Tujuan penelitian ini adalah untuk mengetahui kerapatan jenis, kerapatan relatif jenis, frekuensi jenis, frekuensi relatif jenis, penutupan jenis, penutupan relatif jenis, indeks nilai penting jenis mangrove yang ada di kawasan sekitar PT. Conch Kecamatan Lolak, Kabupaten Bolaang Mongondow, Provinsi Sulawawesi Utara. Penelitian ini dilakukan selama 4 bulan April-Juli 2020. Metode yang dipakai adalah plot kuadrat sebanyak 6 stasiun. Pengambilan data pada setiap stasiun dibuat plot dengan ukuran 10 × 10 m2 untuk mengukur diameter pohon setinggi dada (DBH) yang memiliki lingkar batang minimal 16 cm. Hasil penelitian menunjukkan bahwa ada 5 jenis mangrove yaitu R. apiculata, R. mucronata, B. gymnorhiza, S. alba dan X. granatum. Kerapatan relatif jenis tertinggi pada stasiun 2, yaitu R. mucronata 62,96%, sedangkan nilai terendah pada stasiun 3, yaitu R. mucronata 8,77%, nilai Frekuensi relatif jenis tertingi pada stasiun 4, yaitu R. mucronata 33.33%, sedangkan nilai terendah pada stasiun 5, yaitu B. gymnorhiza 25.00%, nilai Penutupan relatif jenis tertinggi pada stasiun 5, yaitu R. mucronata 30,91%, sedangkan terendah pada stasiun 2, yaitu R. apiculata 12,88%, dan Indeks nilai penting tertinggi pada stasiun 3, yaitu R. apiculata 138,09% dan nilai terendah pada stasiun 5, yaitu X. granatum 35,05%.Kata Kunci: Mangrove, kawasan sekitar PT. Conch, Rhizopora

Vegetation change 10 years after cattle removal in a savanna landscape

Following the establishment of a conservation reserve, changes in ground stratum vegetation following removal of cattle were examined in a northern Australian savanna over a 10-year period. The floristic composition of 40 vegetation plots in lowland savannas were surveyed shortly after acquisition of the property, and then surveyed twice in the following 10 years after cattle removal. Some notable ecosystem-transforming introduced species (weeds) such as Themeda quadrivalvis remained relatively stable, whereas the pasture legume Stylosanthes scabra increased in cover. The species richness of both native and introduced plants increased. Various plant functional groups changed in relative cover, with a decline in relatively unpalatable grasses and a corresponding increase in palatable grasses, responses that are consistent with recovery from grazing pressure. Our results show that removal of cattle in highly disturbed savanna ecosystems can have both positive and negative results for native ground stratum vegetation in the first decade of recovery.

Ecological Characteristics Study of the Vegetation Cover for the Protected Area Faculty of Agriculture at the University of Tripoli-Libya

The aim of this research was to investigate the vegetation characteristics to determine the dominant species because the selected study area never has been ecologically studied before. The study was carried out in the period from April to the end of May 2018 two trips per week. To achieve the study, two methods were used Quadrat Method and Lines-transect Method. 19 lines-transect were randomly distributed with a length of 50 meters in the study area. A total of 92 quadrats 4 m2 selected for perennial plants and 60 quadrats 1 m2 for annual plants (grasses) were distributed to the Line-transect; all plant species and their numbers that appeared in the quadrat were recorded. Vegetation characteristics (density, frequency, and abundance) and their relative values of each plant species were calculated from quadrat, whereas cover and the relative cover was calculated from Line-transect. The results showed that the highest density in annual plants was 32.1 plant / m2 for Stipacapensis followed by Scabiosaarenaria with 15.6 plants /m2, while in perennial plants was found (14.7 plant / m2) for Plantagoalbicans followed by Helianthemumlippii density with (3.26 plant / m2). The obtained results also showed that S.Arenaria has the highest frequency 80%, then S. capensis with 78.30% in annual plants, in perennial plantsP. albicans has the highest frequency (97.8%) followed by H. lippii with (70.6%). It appears from results obtained that the highest cover recorded was (15.8%) for S. capensis followed by P. albicans (12.4%). From the results, the annual plants have the highest value were 187.92 for plant species S. capensis followed by S. arenaria with 148.8. Through the results obtained, the plantcommunity of the study area is Stipa capensis - Scabiosa arenaria Community.

Shrub Encroachment Shapes Soil Nutrient Concentration, Stoichiometry and Carbon Storage in an Abandoned Subalpine Grassland

Soil nutrient stoichiometry plays a substantial role in terrestrial carbon and nutrient cycling. However, the changes in soil nutrient stoichiometry with shrub encroachment (SE) remain poorly understood, especially in subalpine areas. We examined the changes in soil nutrient concentration, nutrient stoichiometry, and organic carbon (OC) storage (at a depth of 0–5, 5–10 and 10–20 cm) in three successional shrub encroachment stages (early, mid and late) in an abandoned subalpine Eulalia pallens (Hackel) Kuntze grassland. An ANOVA showed that SE did not produce serious soil acidification, but significantly increased the soil OC and total phosphorous (TP) concentration, and improved the stoichiometry ratio of soil OC to total nitrogen (OC:TN) in all layers. OC storage tended to increase with SE. SE thus did not indicate degradation of the grassland. A redundancy analysis (RDA) and partial RDA revealed that the shrub relative cover and soil water content were the most important factors affecting the soil nutrient concentration, that the soil available phosphorous (AP), nitrogen, potassium, calcium (ACa), and magnesium concentration and shrub relative cover were the most important factors influencing soil nutrient stoichiometry ratios, and that soil OC:TN, TN:TP, OC:TN:TP, and AP:ACa ratios, bulk density, and pH were the most important factors influencing soil OC storage over SE. Our study provides insights into SE in grassland areas, and potentially provides a useful reference for ongoing grassland conservation and restoration in subalpine regions.

Predicting Yield Losses in Rice Mixed-Weed Species Infestations in California

Although many pests constrain rice production, weeds are considered to be the major barrier to achieving optimal yields. A predictive model based on naturally occurring mixed-species infestations in the field would enable growers to target the specific weed group that is the greatest contributor to yield loss, but as of now no such models are available. In 2013 and 2014, two empirical hyperbolic models were tested using the relative cover at canopy closure of groups of weed species as independent variables: grasses, sedges, broadleaves, grasses and sedges combined, grasses and broadleaves combined, and all weed species combined. Models were calibrated using data from experiments conducted at the California Rice Experiment Station, in Biggs, CA, and validated across four sites over 2 years, for a total of 7 site-year combinations. Of the three major weed groups, grasses, sedges, and broadleaves, the only groups positively related to yield loss in the multispecies infestation were grasses. At the model calibration site, grasses and sedges combined best predicted yield loss (corrected Akaike information criterion [AICc]=−21.5) in 2013, and grasses alone best predicted yield loss (AICc=−19.0) in 2014. Across the validation sites, the model using grasses and sedges combined was the best predictor in 5 out of 7 site-years. Accuracy of the predicted values at the model validation sites ranged from 6% mean average error to 17% mean average error. No single model and set of parameters accurately predicted losses across all years and locations, but relative cover of grasses and sedges combined at canopy closure was the best estimate over the most sites and years.

Response of 110 Kentucky Bluegrass Varieties and Winter Annual Weeds to Methiozolin

Methiozolin is a new isoxazoline herbicide that has scarcely been tested in Kentucky bluegrass turf. A field trial was conducted in Blacksburg, VA, to determine response of 110 Kentucky bluegrass varieties and winter annual weeds to sequential fall applications of methiozolin. At 1.5 and 6 mo after initial treatment (MAIT), Kentucky bluegrass injury I30values (predicted methiozolin rate that causes 30% Kentucky bluegrass injury) ranged between 3.4 to more than 10 times the recommended methiozolin rate for annual bluegrass control. Methiozolin at all rates reduced cover of annual bluegrass, common chickweed, corn speedwell, hairy bittercress, mouseear chickweed, and Persian speedwell but increased cover of parsley-piert. For all varieties, methiozolin at 2 kg ai ha−1increased Kentucky bluegrass cover, turf quality, and turf normalized difference vegetation index (NDVI) relative to the nontreated check at 6 MAIT. Kentucky bluegrass relative cover change (RCC) was attributed primarily to weed control but was inversely correlated with methiozolin rates because of increased weed control and reduced Kentucky bluegrass growth. Despite the decline in RCC with increasing methiozolin rates, most Kentucky bluegrass varieties treated with the highest methiozolin rate (6 kg ha−1) still had greater Kentucky bluegrass cover than the nontreated check at 6 MAIT. Results from this study indicate that two fall applications of methiozolin at rates beyond that previously reported for annual bluegrass control can safely be applied to a broad range of Kentucky bluegrass varieties spanning most of the known genetic classifications.