Seasonal dynamics of nutrients in a Carex meadow

1982 ◽  
Vol 60 (9) ◽  
pp. 1671-1678 ◽  
Author(s):  
Allan N. D. Auclair
Keyword(s):  
Aboveground Biomass ◽  
Seasonal Dynamics ◽  
Seasonal Changes ◽  
Late Summer ◽  
Dry Weight ◽  
Early Summer ◽  
Nutrient Accumulation ◽  
Maximum Accumulation ◽  
Mobility Of Elements ◽  
Uptake And Release

Nutrient accumulation in aboveground biomass and mobilization of nutrients in litter were studied on a Carex meadow in southern Quebec, Canada. Seasonal changes were characterized by short periods of rapid element uptake and release. By late May the total element levels were 80% of maximum. Accumulation of N, P, and K was rapid relative to early increments in biomass. Ca, Mg, and micronutrients were taken up from the soil solution across the season and levels paralleled changes in biomass. In early summer elements were released from litter more rapidly than litter dry weight declined. Mobility of elements decreased in the order K > Mg > P > N > Ca. Overwinter, 83% of K was released, whereas Ca concentration in litter increased overwinter and through the following summer. Immobilization of Fe in litter was pronounced. Overall, > 90% of the element mass in green late-summer shoots was retained in litter overwinter.

Seasonal dynamics and life cycle of Heterotrissocladius marcidus (Diptera: Chironomidae) in high altitude lakes (High Tatra Mts, Slovakia)

Biologia ◽  
2015 ◽  
Vol 70 (7) ◽  
Author(s):  
Katarína Goffová ◽  
Peter Bitušík ◽  
Zuzana Čiamporová-Zatóvičová ◽  
Dana Bukvová ◽  
Ladislav Hamerlík
Keyword(s):  
Life Cycle ◽  
Seasonal Dynamics ◽  
Seasonal Changes ◽  
Alpine Lakes ◽  
Early Summer ◽  
Larval Abundance ◽  
Tatra Mountains ◽  
Tatra Mts ◽  
Summer Decline ◽  
High Tatra Mountains

AbstractWe estimated the seasonal dynamics and life cycle of the chironomid Heterotrissocladius marcidus (Walker, 1856) in three alpine lakes in the High Tatra Mountains (Central Europe). H. marcidus had univoltine cycle in all lakes surveyed and seasonal changes of density showed an early summer and an autumn peak interrupted by a mid-summer decline of larval abundance. Our results indicate that phenology of H. marcidus is sensitive to thermal regime and local differences in lake water temperature can lead to differences of the life history within the same population

Seasonal changes in prevalence and intensity of Cosmocercoides dukae (Nematoda: Cosmocercoidea) in Deroceras laeve (Mollusca)

1987 ◽  
Vol 65 (7) ◽  
pp. 1662-1665 ◽  
Author(s):  
Daryl J. Vanderburgh ◽  
R. C. Anderson
Keyword(s):  
Natural Population ◽  
Seasonal Changes ◽  
Late Summer ◽  
Early Summer ◽  
Late Spring ◽  
New Host ◽  
Histological Sections ◽  
Arion Fasciatus ◽  
New Host Records

A natural population of Deroceras laeve was examined regularly for the presence of Cosmocercoides dukae (Holl, 1928) Travassos, 1931. Transmission of C. dukae in D. laeve occurred in late spring and early summer before adult slugs from the previous year died in July. Transmission to juvenile slugs (hatched from eggs laid in spring) continued in late summer and fall. Histological sections of slugs exposed experimentally to larvae of C. dukae revealed that larvae penetrate slug tissues. Arion fasciatus, Arion hortensis, and Zonitoides nitidus represent new host records for C. dukae.

scholarly journals Phenology of Daphnia in a Northern Italy pond during the weather anomalous 2014

2015 ◽  
Author(s):  
Valeria Rossi ◽  
Catia Maurone ◽  
Giorgio Benassi ◽  
Silvia Marková ◽  
Petr Kotlík ◽  
...  
Keyword(s):  
Seasonal Dynamics ◽  
Phylogenetic Analyses ◽  
Late Summer ◽  
Weather Conditions ◽  
Typical Feature ◽  
Early Summer ◽  
Northern Italy ◽  
Density Peaks ◽  
Temporary Habitats ◽  
Shallow Water Body

<p>This note reports a comparison between <em>Daphnia</em> phenology in the weather anomalous 2014 and a previous three years period (2011-2013), in a shallow water body of Northern Italy (Bodrio del pastore III) where we recorded <em>D. pulex. </em>In 2011-2013, <em>Daphnia</em> population showed 1-2 density peaks from mid spring to early summer, it declined in July-August and did not recover, from ephippia, until the following spring. The seasonal dynamics was probably related to the species thermal tolerance. Males and ephippial females appeared at the beginning of growth season according to a typical feature of <em>Daphnia</em> populations from temporary habitats. The presence of the <em>Chaoborus</em> larvae resulted in juvenile adaptive predator-avoidance cyclomorphosis. In 2014, in the study area, mean winter air temperature was much warmer than average recorded during the past three years while it was much colder than average in July and August. This reflected the relatively rainy and cloudy summer months: the winter and summer precipitations total was above the previous three years average. In 2014, <em>Daphnia</em> was found all over the year and showed a maximum peak of density in November. The general increase of <em>Daphnia</em> was related to a shift in <em>D. pulex</em> population phenology, seasonal growth started earlier and lasted longer, and to the occurrence of <em>D. longispina</em>. Both species were identified by genetic markers and phylogenetic analyses of <em>ND5</em> sequences placed isolates from the Bodrio del pastore III into the European <em>D. pulex </em>group. Both populations reproduced by cyclical parthenogenesis and showed cyclomorphosis. However, <em>D. pulex</em> produced more males and ephippial females than <em>D. longispina. </em>Their seasonal dynamics were quite different: <em>D. longispina</em> dominated in late summer while <em>D. pulex</em> showed the highest density in November. The presence of <em>D. pulex</em> in the Bodrio is important in the framework of conservation ecology especially because we have showed that it is native European strain instead of the invasive North American clone that replaced native <em>D. pulex </em>throughout Africa and was already recorded in Italy. We provide some indications and discuss how <em>Daphnia</em> phenology of shallow lakes of temperate areas may be susceptible to inter-annual variability in weather conditions.</p>

Seasonal changes in leaf and stem loline alkaloids in meadow fescue

2011 ◽  
Vol 62 (3) ◽  
pp. 261 ◽  
Author(s):  
Brian Patchett ◽  
Ravi Gooneratne ◽  
Lester Fletcher ◽  
Bruce Chapman
Keyword(s):  
Seasonal Changes ◽  
Seasonal Pattern ◽  
Late Summer ◽  
Early Spring ◽  
Early Summer ◽  
Sharp Decline ◽  
Meadow Fescue ◽  
Accumulation Pattern ◽  
Loline Alkaloids

Leaf and stem loline alkaloid concentration in 10 European meadow fescue (Festuca pratensis Huds.) lines grown in a field in Canterbury, New Zealand, were determined in samples collected six times between early spring 2004 and late autumn 2005. Significant differences in loline alkaloid concentrations were noted between lines and between harvest times. Higher total loline alkaloid concentrations (up to 4990 µg g–1) were found in stems compared to leaf (up to 1770 µg g–1). However, the seasonal accumulation pattern of different loline alkaloid concentrations in leaf and stem varied. In most lines, stem loline concentration peaked sharply in late spring and declined during early summer and autumn. The seasonal pattern of leaf loline alkaloid concentration followed the stem concentration except for a sharp decline in early summer followed by an increase in late summer. In most instances, the concentration of N-formyl loline was the highest > N-acetyl loline > N-acetyl norloline > N-methyl loline. The possible role of stem and leaf loline alkaloids to deter pasture-feeding insects is briefly discussed.

Seasonal changes in activity patterns and the adaptive value of haying in pikas (Ochotona princeps)

1983 ◽  
Vol 61 (2) ◽  
pp. 411-416 ◽  
Author(s):  
Douglas A. Conner
Keyword(s):  
Surface Activity ◽  
Seasonal Changes ◽  
Activity Patterns ◽  
Winter Season ◽  
Late Summer ◽  
Early Summer ◽  
Cold Temperatures ◽  
Vegetation Growth ◽  
Ochotona Princeps ◽  
Early Fall

Seasonal changes in the performance of four behaviors, perching, haying, feeding, and surface activity were studied in two populations of North American pikas (Ochotona princeps) living in Colorado. During late summer and early fall (July–September), haying, the gathering of meadow vegetation followed by storing it in their talus territories, made up almost 55% of the pikas' surface activity. After haying ceased, pikas continued to feed in the meadows until snowpack, cold temperatures, and the absence of surface vegetation made this impossible. Beginning in February, individuals remained under the snowpack feeding on vegetation from their hay piles and on lichens available below the snow. Surface activity was not seen again until May when spring vegetation began to appear. Haying appears to be an adaptive response to environmental unpredictability. Hay piles most likely become critical for survival when harsh weather prevents surface foraging and(or) delays the emergence of new vegetation growth in the spring or early summer. It is suggested that the evolution of territoriality in pikas is related to the need to gather sufficient vegetation to serve as a potential winter food supply during years when the winter season is unusually harsh or prolonged.

Marine zooplanktonic and benthic community respiration rates at Resolute, Canadian high Arctic

1997 ◽  
Vol 54 (5) ◽  
pp. 995-1005 ◽  
Author(s):  
H E Welch ◽  
T D Siferd ◽  
P Bruecker
Keyword(s):  
Benthic Community ◽  
Ecosystem Respiration ◽  
Seasonal Pattern ◽  
Late Summer ◽  
Dry Weight ◽  
High Arctic ◽  
Early Summer ◽  
Community Respiration ◽  
Respiration Rates ◽  
Total Ecosystem Respiration

Benthic community respiration rates and macrozooplankton (>202 µm) biomass and respiration rates were measured throughout a calender year at Resolute (74°42 prime N, 94°50 prime W). The plankton averaged 7.2 g dry weight · m-2 with no seasonal pattern and respired 82 g O2 · m-2 · yr-1. Gelatinous and chaetognath predators made up 10% of macrozooplankton biomass and respired 6.4% of planktonic respiration. The lipid content of the nongelatinous fraction fluctuated seasonaly from 64% of dry weight in midwinter to 46% in early summer. The benthic soft-bottom community inside Resolute Bay respired about 125 g O2 · m-2 · yr-1, with a twofold rate increase in late summer. Offshore on hard bottom the few measurements we obtained suggested a respiration rate of about 75 g O2 · m-2 · yr-1. The macrozooplankton and benthos were therefore approximately equal in energy flow. The total ecosystem respiration of 157 g O2 · m-2 · yr-1 corroborated a previous independent estimate of photosynthesis of 60 g C · m-2 · yr-1 for the region. Microplankton respiration appeared to be relatively low. Our results are consistent with the hypothesis that the proporion of primary production exported to the benthos increases with decreasing water temperature and depth, increasing latitude, and increasing cell size.

Observations on the Seasonal Changes of the Parasite Fauna of Yellow Perch (Perca flavescens) from the Bay of Quinte, Lake Ontario

1969 ◽  
Vol 26 (4) ◽  
pp. 833-843 ◽  
Author(s):  
Shibru Tedla ◽  
C. H. Fernando
Keyword(s):  
Seasonal Dynamics ◽  
High Intensity ◽  
Seasonal Changes ◽  
Yellow Perch ◽  
Perca Flavescens ◽  
Late Summer ◽  
Lake Ontario ◽  
Parasite Fauna ◽  
Early Fall ◽  
Larval Parasites

The seasonal changes in incidence and intensity of infestation of yellow perch, Perca flavescens, by adult and larval parasites, both external and internal, were studied over a period of 1 year. Eight species of parasites were numerous enough to permit analysis of seasonal dynamics. Bunodera luciopercae and Echinorhynchus salmonis showed a high infestation in the fall and declined gradually to zero by late summer. New infestation occurred in early fall. Protocephalus pearsei showed the highest incidence in summer and a lower level during the rest of the year without any marked fluctuations. The intensity of infestation remained relatively constant throughout the year. Ergasilus confusus reached its peak of incidence in the summer, declined through the fall and winter, and began increasing in spring. Intensity of infestation showed parallel changes. In February, however, both incidence and intensity were high. Diplostomulum huronense showed a high intensity of infestation in November. The incidence remained fairly constant throughout the rest of the year. Urocleidius adspectus showed no seasonal variability as regards incidence but the intensity of infestation was highest in August and September. Contracaecum spiculigerum showed no distinct seasonal changes in incidence or intensity. Glochidial infestation reached a high intensity in July. This was due to the glochidia of Lampisilis radiata siliquoidea.

scholarly journals Seasonal changes of foraging habitats and prey species in the Japanese Crested Ibis Nipponia nippon reintroduced on Sado Island, Japan

2012 ◽  
Vol 23 (4) ◽  
pp. 445-453 ◽  
Author(s):  
CHIHIRO ENDO ◽  
HISASHI NAGATA
Keyword(s):  
Seasonal Changes ◽  
Prey Species ◽  
Capture Rate ◽  
Management Strategies ◽  
Late Summer ◽  
Prey Type ◽  
Early Summer ◽  
Terrestrial Invertebrates ◽  
Nipponia Nippon ◽  
Crested Ibis

SummarySeasonal foraging habitats, prey species and foraging frequency of Japanese Crested Ibis Nipponia nippon in farmland were studied one year after its reintroduction on Sado Island, Japan. Paddies were the main foraging habitat in spring, early summer, autumn and winter. In late summer, ibises often used levees around paddies, grasslands, uncropped paddies and abandoned paddies. Small invertebrates were important prey components in terms of frequency (70–90%) throughout the year. Ibises took Misgurnus loaches (less than 20% of prey captured) throughout the year; the capture rate of loaches in ditches was especially high in winter. Ibises depended on terrestrial invertebrates, including earthworms, particularly in late summer. No clear correlations between the rate of capture for each prey species and the proportion of habitat use in each season were detected. However, abandoned and uncropped paddies provided suitable habitats for the ibis because human disturbance was relatively low and the rate of capture for each prey type was relatively high throughout the year. Management of grass height in grasslands and on levees around the paddies will be effective in ensuring the availability of foraging habitats in late summer. Seasonal changes in the availability of foraging habitats in farmland ecosystems should be considered when designing effective management strategies for the establishment of Japanese Crested Ibis populations.

Growth of heath vegetation. II. The seasonal growth of a heath on ground-water Podzol at Wilson's Promontory, Victoria

1965 ◽  
Vol 13 (2) ◽  
pp. 281 ◽  
Author(s):  
RH Groves
Keyword(s):  
Soil Moisture ◽  
Ground Water ◽  
Shoot Growth ◽  
Late Summer ◽  
Dry Weight ◽  
Early Summer ◽  
Second Phase ◽  
Root Weight ◽  
Seasonal Growth ◽  
Third Phase

The seasonal growth of a heath on a ground-water podzol in southern Victoria is presented. Seasonal changes in the dry weight of standing vegetation, dry weight of surface roots, and soil moisture were followed. Three phases of growth are obvious. The first phase, shoot growth in late spring-early summer, may be the result of a redistribution of metabolites. During the second phase, a significant increase in the dry weight of tops may occur; this presumably leads to an increase in evapotranspiration and a decrease in soil moisture. Death of some roots then occurs, followed by abscission of older leaves and death of weaker plants. Any increase in the biomass of tops is thus cancelled in this heath ecosystem. With reduction in leaf area, evapotranspiration decreases and soil moisture increases. In this third phase in late summer, the root weight increases to approximately that of the previous winter. Thus the ecosystem maintains a fluctuating equilibrium in root-top biomass from year to year.

Effects of Dried Distillers’ Grains Cube Supplementation for Steers Grazing Introduced Pastures on Animal Performance and Forage Production

2021 ◽  
Vol 99 (Supplement_2) ◽  
pp. 12-13
Author(s):  
Jordan Adams ◽  
Rodney Farris ◽  
Scott Clawson ◽  
Earl Ward ◽  
Paul Beck
Keyword(s):  
Festuca Arundinacea ◽  
Statistical Power ◽  
Cynodon Dactylon ◽  
Animal Health ◽  
Late Summer ◽  
Early Summer ◽  
Distillers Grains ◽  
Forage Production ◽  
Trenbolone Acetate ◽  
Dried Distillers Grains

Abstract We evaluated the effects of supplementing dried distillers’ grains cubes (DDGS) and re-implantation of steers (n = 149; BW = 238 ± 13.8 kg) grazing tall fescue (Festuca arundinacea)/bermudagrass (Cynodon dactylon) pastures (n = 9 pastures, 7.2 ± 2.90 ha) from 14 April to 17 September 2020 (n = 155 d) in a split-plot design on steer performance and forage production. Main plot supplemental treatments (n = 3 pastures/treatment) included 1) Fertilized Control (FC), no supplementation on fertilized pastures (112 kg N/ha); 2) Fertilized Supplement (FS), supplemental DDGS fed at 2.9 kg 3-d/wk on fertilized pastures; and 3) Supplement (S), supplemented DDGS at 0.75% BW/d on unfertilized pastures prorated for 5-d/wk feeding. Steers were previously implanted during receiving with 40 mg trenbolone acetate and 8 mg estradiol (REV-G; Revalor G, Merck Animal Health). On July 7, steers in each pasture were randomly assigned to one of three re-implant treatments: 1) no re-implant; 2) REV-G; or 3) 200 mg progesterone and 20 mg estradiol (Synovex S, Zoetis Animal Health). Steers in FS and S gained more (P &lt; 0.01) than FC throughout the trial and final BW was greater (P &lt; 0.01) for FS and S compared with FC. Unexpectedly, re-implanting had no effect on ADG (P = 0.57) or BW (P = 0.34), but statistical power may be lacking. Supplemental efficiency was greater in the late summer for FS (P = 0.05) compared to S. Fertilizing pastures in FS and FC did not affect biomass (P = 0.39), however, CP was increased (P = 0.01) and acid and neutral detergent fibers tended to decrease (P = 0.06) relative to S in the early summer (April, May, June, and July), but did not differ in late summer (August and September). Based upon our analysis, DDGS is a suitable supplement and can replace N fertilizer for steers grazing introduced pastures.

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