Simulation of salmonberry and thimbleberry population establishment and growth

1993 ◽  
Vol 23 (10) ◽  
pp. 2194-2203 ◽  
Author(s):  
Bruce D. Maxwell ◽  
John C. Zasada ◽  
Steven R. Radosevich
Keyword(s):  
Canopy Cover ◽  
Early Spring ◽  
Early Summer ◽  
Phenological Stages ◽  
Simulation Accuracy ◽  
Life History Stages ◽  
Demographic Processes ◽  
Species Specific ◽  
Summer Fruit ◽  
Number Of Individuals

A salmonberry (Rubusspectabilis Pursh) and thimbleberry (Rubusparviflorus Nutt.) population simulation model was developed and compared with field observations for verification and validation. The species-specific influence of different phenological stages (early spring bud break, early summer fruit set, and fall senescence), different environments (at different sites), and intraspecific density on demographic processes was incorporated into the model. The model predicts the number of individuals in different life-history stages at three phenological stages during a growing season. Simulations were most accurate when compared with low genet density planted populations. Salmonberry populations on a moist site were most accurately simulated. Thimbleberry simulation accuracy was reduced by poor prediction of sprout densities. Salmonberry and thimbleberry population response to an application of glyphosate was simulated and compared with observed canopy cover for 3 years following application. The simulated response was accurate for the 1st year following application, but did not account for continued canopy cover in the observed populations. Salmonberry canopy cover and mean ramet height in response to manual cutting at three phenological stages was also simulated. The model simulations indicated that the most prolonged reduction in salmonberry cover followed cutting at the reproductive stage of growth.

scholarly journals Animal welfare risks of global aquaculture

2021 ◽  
Vol 7 (14) ◽  
pp. eabg0677
Author(s):  
Becca Franks ◽  
Christopher Ewell ◽  
Jennifer Jacquet
Keyword(s):  
Animal Welfare ◽  
Taxonomic Diversity ◽  
Aquatic Animal ◽  
Multiple Sources ◽  
Aquatic Animals ◽  
Extreme Risk ◽  
Unknown Species ◽  
High Production ◽  
Species Specific ◽  
Number Of Individuals

The unprecedented growth of aquaculture involves well-documented environmental and public-health costs, but less is understood about global animal welfare risks. Integrating data from multiple sources, we estimated the taxonomic diversity of farmed aquatic animals, the number of individuals killed annually, and the species-specific welfare knowledge (absence of which indicates extreme risk). In 2018, FAO reported 82.12 million metric tons of farmed aquatic animals from six phyla and at least 408 species—20 times the number of species of farmed terrestrial animals. The farmed aquatic animal tonnage represents 250 to 408 billion individuals, of which 59 to 129 billion are vertebrates (e.g., carps, salmonids). Specialized welfare information was available for 84 species, only 30% of individuals; the remaining 70% either had no welfare publications or were of an unknown species. With aquaculture growth outpacing welfare knowledge, immediate efforts are needed to safeguard the welfare of high-production, understudied species and to create policies that minimize welfare risks.

The effects of burning on Festuca hallii in the parklands of central Alberta

1995 ◽  
Vol 73 (6) ◽  
pp. 937-942 ◽  
Author(s):  
Heather Sinton Gerling ◽  
Arthur W. Bailey ◽  
Walter D. Willms
Keyword(s):  
Standing Crop ◽  
Growing Season ◽  
Early Spring ◽  
Leaf Length ◽  
Tiller Number ◽  
Phenological Stages ◽  
University Of Alberta ◽  
Festuca Hallii ◽  
Tiller Density ◽  
The University

The response of Festuca hallii (Vassey) Piper to time of burning was examined on the Festuca–Stipa grasslands of the Aspen Parklands at the University of Alberta Ranch located 150 km southeast of Edmonton, Alberta. Two defoliation treatments (burning and mowing) were examined on five dates in 1978 (8 April, 27 April, 1 June, 31 July, and 18 October), corresponding to different phenological stages of F. hallii. Burning and mowing reduced the standing crop of F. hallii produced in the first growing season after treatment, but tiller densities increased. Defoliation in early spring (8 April) had little effect on the standing crop; apparently the increase in tiller density compensated for the reduction in tiller length. Inflorescence density also increased following burning or mowing from 8 April to 1 June. Soil temperature (3 cm deep) on previously burned or mown sites was greater than on the control the year after treatment. Festuca hallii tolerates single burns at any time of the year, but early spring fires have the greatest benefits by increased tillering and standing crop. Key words: standing crop, tiller number, leaf length, litter, defoliation, mowing.

scholarly journals Relationships between water transparency and abundance of Cynodontidae species in the Bananal floodplain, Mato Grosso, Brazil

2009 ◽  
Vol 7 (2) ◽  
pp. 251-256 ◽  
Author(s):  
Cesar Enrique de Melo ◽  
Jane Dilvana Lima ◽  
Eliete Francisca da Silva
Keyword(s):  
Fish Assemblages ◽  
Water Transparency ◽  
Predatory Fish ◽  
Mato Grosso ◽  
Central Brazil ◽  
Fish Group ◽  
Species Specific ◽  
Abundance And Distribution ◽  
Number Of Individuals ◽  
Habitat Affinities

The Cerrado in the Central Brazil is currently one of the most threatened ecosystems in the world. As a result, the aquatic habitats in this biome also undergo great impacts. Alterations related to land-use change increase sediment loadings in rivers, streams and lakes, resulting in sedimentation and decrease in water transparency. Water transparency determines underwater visibility conditions, and as a consequence fish assemblages respond to spatial and temporal changes in this variable. This work aimed to examine the influence of transparency on the abundance and distribution of Cynodontidae species, a visually oriented predatory fish group. Fish sampling was conducted in 15 sites located between Mortes and Araguaia rivers in the Bananal floodplain, Mato Grosso State. Regression analysis between relative abundance of Cynodontidae (in number of individuals and biomass) and water transparency showed a positive and highly significant correlation, indicating that this group shows species-specific habitat affinities for clearer waters. These results suggest that the increase in water turbidity in this region can affect the patterns of abundance and distribution of the Cynodontidae species, as well as other visually oriented fishes.

scholarly journals MANAGEMENT OF LATE SPRING-EARLY SUMMER PASTURE SURPLUSES IN HILL COUNTRY

1984 ◽  
pp. 199-206 ◽  
Author(s):  
G.W. Sheath ◽  
R.W. Webby ◽  
W.J. Pengelly
Keyword(s):  
Early Spring ◽  
Early Summer ◽  
Late Spring ◽  
First Year ◽  
Hill Country ◽  
Continuous Grazing ◽  
Summer Pasture ◽  
Animal Performances ◽  
Grazing Policy ◽  
Made In

Comparisons of controlling late spring to early summer pasture growth on either easy or steep contoured land with either a fast rotation or continuous grazing policy were made in self-contained farmlets for two years. Pasture control was maintained over more land by controlling steep land first and with continuous grazing. Animal performances (ewes, steers) were generally similar for the mid-November to early January treatment period, and subsequently until May shearing. In the first year better animal performances occurred in "steep control" farmlets during winter and early spring, but this was less evident in the second year. Priority control of steep land during late spring-early summer is recommended because of likely longer-term benefits in pasture composition,density and production. Quick rotation grazing through the period provides a better ability to recognise and manage pasture quantities and should be adopted if summer droughts are anticipated. For well fenced properties in summer-wet areas and with integrated stock grazing, continuous grazing during late spring-early summer may be equally suitable. Keywords: hill country, grazing management, pasture control

scholarly journals Seasonal patterns of pasture production in the Bay of Plenty and Waikato

1991 ◽  
pp. 67-72
Author(s):  
J.A. Baars ◽  
G.J. Goold ◽  
M.F. Hawke ◽  
P.J. Kilgarriff ◽  
M.D. Rolm
Keyword(s):  
Growth Rates ◽  
Early Spring ◽  
Early Summer ◽  
Growth Patterns ◽  
Climatic Data ◽  
Large Contribution ◽  
Pasture Production ◽  
Summer Peak ◽  
The Difference

Patterns of pasture growth were measured on 3 farms in the Bay of Plenty (BOP) and at No2 Dairy (Ruakura Agricultural Centre) in the Waikato from 1989 to 199 1. A standardised trim technique with cages and 4-weekly cutting under grazing was used. Long-term seasonal growth patterns, using a predictive pasture model, were also simulated. Simulated pasture growth from long-term climatic data shows that pasture growth rates are higher in winter, early spring and late autumn in the BOP than the Waikato. However, the actual measurements over the 2 years show that pasture growth over the latter periods is lower at the BOP sites than at the Waikato site. In the BOP the spring peak is much later than in the Waikato while an early summer peak, with higher growth rates than in the Waikato, occurred in the BOP. No such summer peak was evident in the Waikato. The difference between the two regions is caused by the large contribution of subtropical grasses to sward production in summer and autumn, The prolific summer growth of subtropical grasses may explain the low ryegrass content and low pasture production in winter. The lower than expected autumn, winter, spring production may also becaused by low clover content, possibly a result of competition from subtropical grasses and a sulphur deficiency. The apparent low amount of nitrogen fixed by clover may explain the low rates of pasture production over the cooler season. Applications of nitrogen fertiliser may substantially increase dry matter production from April to September. Keywords pasture,simulation,subtropical grasses, Paspalum, Digitaria sanguinalis, growth rates

The diet of grizzly bears in the Flathead River drainage of southeastern British Columbia

1995 ◽  
Vol 73 (4) ◽  
pp. 704-712 ◽  
Author(s):  
Bruce N. McLellan ◽  
Fred W. Hovey
Keyword(s):  
National Park ◽  
Ursus Arctos ◽  
Handling Time ◽  
Early Spring ◽  
Early Summer ◽  
Grizzly Bears ◽  
Green Vegetation ◽  
Heracleum Lanatum ◽  
Shepherdia Canadensis ◽  
Food Consumed

Based on the analysis of 1100 feces or scats, the seasonal diet of grizzly bears (Ursus arctos) in the Flathead drainage between 1979 and 1991 was estimated. In the early spring, major foods included ungulates and hedysarum roots (Hedysarum sulphurescens). Later in the spring and early summer, green vegetation that mainly included horsetails (Equisetum arvense), graminoids, and cow parsnip (Heracleum lanatum) dominated the diet. Later in the summer, berries, particularly huckleberries (Vaccinium spp.) and soopolallie (Shepherdia canadensis), were most common. In the autumn, berries, ungulates, and hedysarum roots were major foods. Seasonal changes in nutrients were measured for major foods. The volume of a food consumed within a season was inversely related to food quality, suggesting that food availability and handling time may have been more important factors influencing diet selection. The proportions of food items in the scats, and species of fruit in particular, varied among years. The Flathead and contiguous Waterton Lakes National Park are so far the only study areas in North America that contain all major bear foods found across the interior of the continent, and in particular, both major berry species, huckleberries and soopolallie. This observation supports the hypothesis that a favourable food base in the Flathead is partially responsible for the high density of bears found there. It is important for managers to realize the possible uniqueness of the Flathead area and not extrapolate information without due caution.

Pollen development in relation to phenological stages of inflorescence expansion in Amelanchier alnifolia (saskatoon), with a comparison with buds forced out of dormancy

1999 ◽  
Vol 77 (2) ◽  
pp. 262-268
Author(s):  
Michael J Sumner ◽  
William R Remphrey ◽  
Richard Martin
Keyword(s):  
Time Frame ◽  
Early Spring ◽  
Flower Buds ◽  
Flower Bud ◽  
Phenological Stages ◽  
Inflorescence Development ◽  
Amelanchier Alnifolia ◽  
Bud Development ◽  
Internal Development ◽  
Flower Bud Development

A relationship was developed between phenological stages of inflorescence expansion and the internal development of pollen within the anther of Amelanchier alnifolia Nutt. flowers. The major microscopic events associated with microsporogenesis and microgametogenesis were correlated with seven stages of external inflorescence development in both natural buds and those forced from dormancy in different concentrations of gibberellin at various times of the year. In fall and early spring, it was found that gibberellin at a concentration of 2.5 mg/L forced buds to produce inflorescences that most resembled those from natural field populations. However, it was not possible to force flower buds to develop all the way to anthesis. Flower bud development stopped when the pollen was at the binucleate stage. Despite this limitation, the ability to force buds increases the time frame for the study of many aspects of the reproductive biology of A. alnifolia.Key words: microsporogenesis, microgametogenesis, gibberellin, GA, flowering.

Fruit viability on grubbed Nassella trichotoma (Nees) tussocks

2002 ◽  
Vol 42 (8) ◽  
pp. 1057 ◽  
Author(s):  
S. Lamoureaux ◽  
G. Bourdôt
Keyword(s):  
New Zealand ◽  
High Risk ◽  
Developmental Stage ◽  
Root System ◽  
Seed Bank ◽  
Soil Seed Bank ◽  
Leaf Sheath ◽  
Early Summer ◽  
Late Spring ◽  
Summer Fruit

An experiment was conducted to determine the influence of time of grubbing in the late spring–early summer, panicle developmental stage at grubbing, and the presence or absence of roots on grubbed plants, on the initial and post-senescent viability of fruits of Nassella trichotoma in North Canterbury, New Zealand. The percentage of fruits viable, following desiccation of panicles removed from plants grubbed in the field, increased from 1% for panicles just beginning to emerge from the leaf sheath, to 49% for panicles fully extended at the time of grubbing. Similarly, as grubbing date was delayed from late November (late spring) until late December (early summer), fruit viability increased from 0.3 to 47%. Overall, 36% of the fruits were viable on panicles at the time of grubbing, increasing slightly to 47 and 44%, respectively, after a period of desiccation with and without the panicles being attached to the grubbed plant's root system. It was concluded that if recruitment of fruits of N. trichotoma to the soil seed bank is to be prevented in North Canterbury, plants must be uprooted before panicle extension. Delaying grubbing to when panicles are fully extended, while possibly enabling a higher percentage of plants to be detected and therefore destroyed, carries with it a high risk of permitting the recruitment of viable fruits to the soil seed bank.

scholarly journals Influence of a Municipal Solid Waste Landfill on the Surrounding Environment: Landfill Vegetation as a Potential Risk of Allergenic Pollen

2019 ◽  
Vol 16 (24) ◽  
pp. 5064 ◽  
Author(s):  
Magdalena Daria Vaverková ◽  
Dana Adamcová ◽  
Jan Winkler ◽  
Eugeniusz Koda ◽  
Jana Červenková ◽  
...  
Keyword(s):  
Plant Species ◽  
Low Cost ◽  
Late Summer ◽  
Cost Effective ◽  
Early Spring ◽  
Early Summer ◽  
Allergenic Pollen ◽  
Grass Species ◽  
Vegetation Monitoring ◽  
Growing Seasons

When the landfill use comes to end, important subsequent steps include aftercare, safety assurance, and ecological regeneration. Landfill revegetation is cost-effective and eco-friendly approach in the management of landfill areas, which serves the purpose of stabilization and provides a pleasant landscape. There are various vegetation types that can be planted, yet grass species are often used for low-cost reasons. Plants can be important sources of air pollution, particularly by grass pollen. The main goal of our study was to identify plant species that produce allergenic pollen. Long-term vegetation monitoring took place on three sites in the growing seasons of years 2008–2018. Studied objects were landfills located in the Czech Republic. The vegetation was assessed using a floristic survey of identified plant species. Plant species that produced allergens were recorded. During the monitoring, 298 plant species were determined. Plant species with allergenic pollen have a considerable share in the landfill vegetation. Thus, landfills are potential sources of various kinds of allergenic pollen. Moreover, our results indicated that there are three periods of pollen production: early spring, late spring, and early summer; late summer; and autumn. The second period is typical for the production of highly allergenic pollen by grasses. Most detected plant species with allergenic pollen are common for all monitored sites, which demonstrates that the vegetation of landfills is a significant source of allergenic pollen.

Seasonal succession of diatom epiphyton on dense mats of Lemna minor

1985 ◽  
Vol 63 (12) ◽  
pp. 2332-2339 ◽  
Author(s):  
L. G. Goldsborough ◽  
G. G. C. Robinson
Keyword(s):  
Lemna Minor ◽  
Algal Growth ◽  
Seasonal Succession ◽  
Ambient Air ◽  
Early Spring ◽  
Early Summer ◽  
Algal Community ◽  
Light Limitation ◽  
Total Biomass

Annual sequences of biomass, species diversity, and community composition of epiphytic diatoms on a dense mat of Lemna minor L. growing in a freshwater marsh are described. In 2 successive years, maximum biomass occurred in early spring prior to occlusion of the water surface by the mat, while diversity reached relative maxima in the early summer (during a period of declining total biomass) and late fall. Ambient air temperature (possibly through a relationship with in situ metabolic activity and nutrient availability) was significantly correlated with community ordination scores on a temporal basis. Depth profile maxima of diatom abundance on vertically positioned artificial substrata occurred below the mat, suggesting that light limitation of algal growth within dense mats may be of lesser importance. Dominant diatom species in the spring and fall were generally ubiquitous in the surrounding marsh, while the major taxa in midsummer, Achnanthes hungarica, Amphora veneta, and Navicula twymaniana, may be specific to the Lemna microhabitat. The development of algal community specificity within a defined seasonal range is discussed in terms of the relative importance of host exudates versus exogenous nutrients as the basis for algal-substratum associations.

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