Macroinverfebrate Abundance and Production of Psammophifous Chironomidae in Shifting Sand Areas of a Lowland River

1985 ◽  
Vol 42 (7) ◽  
pp. 1296-1302 ◽  
Author(s):  
Daniel A. Soluk

Abundance and biomass of benthic macroinvertebrates from shifting sand areas in the bed of the Sand River in central Alberta, Canada, were examined for 1 yr. Macroinvertebrate density ranged from 12 000 to 78 000 individuals/m2, but total biomass was low (50–490 mg/m2 dry mass) due to the small size of most organisms. The interstitial larvae of two chironomid species (Robackia demeijerei and Rheosmittia sp.) contributed a mean of 80.6% biomass and 92.8% of total number of macroinvertebrates. Total annual secondary production of these two species (752.0 ± 144.5 mg∙m−2∙yr−1) was used as an estimate of total secondary production of benthic macroinvertebrates in shifting sand areas. Both R. demeijerei and Rheosmittia sp. exhibited larval growth and development rates much slower than those reported for comparably sized species in other habitats. Food or frequent disturbance may limit the growth of these species. Although unit area biomass and production were low relative to other lotie habitats, shifting sand areas make significant contributions to the river ecosystem because they occupy a large proportion of the river bed.

1982 ◽  
Vol 60 (12) ◽  
pp. 3196-3205 ◽  
Author(s):  
Joseph B. Rasmussen

The heated area of Lake Wabamun prior to macrophyte harvesting had higher submerged macrophyte production, greater amounts of plant detritus in the sediment, and a higher standing crop of benthic macroinvertebrates than the unheated area. Species composition of the benthic macroinvertebrate community was also much different in the heated area with the warmest areas supporting a community dominated by tubificid oligochaetes (Limnodrilus hoffmeisteri and Tubifex tubifex), and the moderately heated areas supporting a community dominated by large Chironomus species (Chironomus plumosus and Chironomus atroviridis). Benthos of the unheated parts of the lake consisted mainly of smaller chironomid species such as Chironomus maturus, C. (cf.) staegeri, Polypedilum nubeculosum, Cladotanytarsus spp., and Tanytarsus spp. The heated area was subjected to mechanical macrophyte harvesting which removed the majority of the submerged macrophytes. This reduced the amount of plant detritus within the sediment and also the standing crop of benthic macroinvertebrates in the heated area. Species composition of the oligochaete-dominated community was not affected by harvesting. Species composition of the Chironomus-dominated area was greatly affected by harvesting and became more similar to that of the unheated area; densities of the large Chironomus species were reduced to low levels, while the densities of smaller chironomid species increased.


2012 ◽  
Vol 12 (3) ◽  
pp. 124-132 ◽  
Author(s):  
Thiago Cesar Lima Silveira ◽  
Gilberto Gonçalves Rodrigues ◽  
Gabriela Peixoto Coelho de Souza ◽  
Norma Luiza Würdig

Wetlands are important because they have high biodiversity and are considered, by environmental agencies, permanently protected areas due to their importance to conservation. In Southern Brazil the aquatic macrophyte Typha domingensis is harvested to be used in the manufacture of handicraft, being an important income source to small farmers. This work aims to test the cut effect of T. domingensis on benthic macroinvertebrates as well as on macrophyte regeneration. These phenomena were analyzed in small areas (1 m²) in a T. domingensis stand by comparing cut treatments and control treatments. Macroinvertebrate were sampled with a corer in the following time sequence after the cut event in both treatments: one day, 26 days, 60 days, 89 days, and 182 days. Macrophyte regeneration was monitored through monthly measurements at each treatment. The macroinvertebrate density did not differ between treatments (ANOVA, p < 0.05). Among the 23 taxa identified, Tubificidae was the only family to response to cut treatment. DCA showed an overlapping between treatments indicating a not clear pattern. The growth of T. domingensis shoots was not affected by the disturbance. Macrophyte regeneration was quick when comparing the treatments and statistical differences were found in one day after the disturbance and 26 days after the disturbance, whereas no differences were found in the remaining sampling dates (60, 89 and 182 days). Observing the macroinvertebrate response and the T. domingensis regeneration, our results suggest that sustainable use of this macrophyte is possible on a small scale.


2006 ◽  
Vol 24 (4) ◽  
pp. 213-217
Author(s):  
S.M. Scheiber ◽  
Richard C. Beeson

Abstract Begonias (Begonia semperflorens) were transplanted into an open-sided clear polyethylene covered shelter to evaluate the effect of root ball condition on establishment and growth. Three root ball classes were evaluated: non root-bound (NRB; 6 week old plants), root-bound (RB; 10 week old plants), and root-bound with the bottom 1 cm of the root ball removed (RBM). Non root-bound plants had greater growth rates for both height and faster rates of accumulation for cumulative root dry mass and new root dry mass relative to the other treatments tested. Cumulative shoot dry mass, new shoot dry mass, and total biomass accumulation rates were slower among RB plants compared to other rootball conditions. Mean canopy size, shoot dry mass, and biomass of NRB were significantly less at transplant; however all parameters were comparable among treatments 12 weeks later. Final mean shoot to root ratios were lower for the NRB treatment relative to RBM. Results indicate smaller, NRB transplants establish faster in the landscape. Furthermore, rootball manipulation is not recommended as it had no significant effect on root establishment or canopy growth of this annual bedding plant in the landscape.


HortScience ◽  
2000 ◽  
Vol 35 (3) ◽  
pp. 429E-429
Author(s):  
John M. Ruter

Decline of certain container-grown ornamental species during the hottest months of summer is a common problem for nurserymen in the southeastern United States. When roots are killed due to high root-zone temperatures and growth ceases, production of plant hormones also decreases. A study was conducted with Early Harvest PGR (Griffin LLC, Valdosta, Ga.), which contains cytokinins, gibberellic acid, and indole butyric acid, to determine if this product would improve the growth of five ornamental species that typically decline during the summer in south Georgia nurseries. The species used were Cotoneaster dammeri Schneid. `Coral Beauty', Cotoneaster salicifolius Franch. `Green Carpet', Spiraea japonica L. `Shirobana', Thuja occidentalis L. `Little Giant', and Weigela florida (Bunge) A. DC. `Minuet'. The treatments (control, 1.5 and 3.0 mL Early Harvest PGR/1125 mL water) were applied every 2 weeks from mid-June until mid-Sept. 1999 as a foliar drench. Treatment of both Cotoneaster species and the Thuja with Early Harvest PGR resulted in little influence on plant growth. While growth indices did not increase, shoot dry mass of Spiraea and Weigela increased 17% and 26%, respectively, when treated with Early Harvest PGR at the medium rate. Plant quality ratings for Spiraea increased when the 1.5-mL rate of Early Harvest PGR was applied. A rate of 3.0 mL of Early Harvest PGR on Spiraea decreased shoot and root dry mass, total biomass, root ratings, and final plant quality. Root ratings and plant quality were highest for Weigela grown with the 1.5-mL Early Harvest PGR treatment. These results indicate that treatment of woody ornamentals with Early Harvest PGR for positive results is both species- and rate-dependent.


2008 ◽  
Vol 49 (1) ◽  
pp. 47-58 ◽  
Author(s):  
Kadri Kõresaar ◽  
Priit Kõresaar ◽  
Malle Mandre

Edela-Eesti luitemetsade järelkasvu arengust ning uuenemistingimustest sambliku ja pohla kasvukohatüübis On the southwestern coast of Estonia dune pine forest covers approximately 3000 hectares. This area includes coastal pine forests. The dune pine forest natural renewal in Southwest Estonia is the object of research. The natural regeneration of Scots pine (Pinus sylvestris L.) at the cowberry site type and at the lichen site type are observed. The necessary observations were made and primary data were collected in 1999-2006 from 28 sample plots, wherefrom 16 were situated at the lichen and 12 at the cowberry site type. The aim of the present study was to find out how old stand and forest site type influences the growth of second growth (height, height increment, age and number of trees per unit area) and its morphological parameters (length of needles and shoots and their dry mass).


2012 ◽  
Vol 69 (3) ◽  
pp. 421-428 ◽  
Author(s):  
May Gómez ◽  
Ico Martínez ◽  
Ismael Mayo ◽  
José Miguel Morales ◽  
Angelo Santana ◽  
...  

Abstract Gómez, M., Martínez, I., Mayo, I., Morales, J. M., Santana, A., and Packard, T. T. 2012. Testing zooplankton secondary production models against Daphnia magna growth. – ICES Journal of Marine Science, 69: 421–428. Modelling secondary production rates in the zooplankton is essential for population ecology studies, but assessing these rates is difficult and rarely done. Here, five secondary production models are tested by measuring Daphnia magna growth. To provide a range of growth rates, Daphnia were cultured under three different nutrition regimes (yeast, cornflour, and phytoplankton). Length and biomass were monitored daily in three simple time-course experiments to provide the growth rates, which ranged from 0.11 to 0.30 d–1 with secondary production rates of 350–643 µg dry mass d−1. Secondary production was predicted best by the freshwater crustacean-based model of Stockwell and Johannsson (1997). Marine copepod-based marine models were totally unsuitable.


1993 ◽  
Vol 71 (4) ◽  
pp. 735-743 ◽  
Author(s):  
Michael B. Griffith ◽  
Sue A. Perry ◽  
William B. Perry

Paracapnia angulata in West Virginia occurs in headwater streams that range in pH from 4.5 to 7.5. It is representative of a number of species of Plecoptera, which often increase in abundance in acidic streams because they are tolerant of low pH and related changes in water quality associated with acid precipitation. We compared growth rates and secondary production of P. angulata in four streams, SFR, WS4, WS3, and HSR, in which mean streamwater pH was 4.26, 5.99, 6.07, and 7.48, respectively. Mean specific growth rates, in terms of dry mass for P. angulata, were higher in the two neutral streams than in the more alkaline stream or the acidic stream. Secondary production of P. angulata was highest in the acidic stream SFR, 106.2 ± 16.4 mg∙m−2∙yr−1 (mean ± 2 SE), and was 34.0 ± 12.1 mg∙m−2∙yr−1 in WS4, 32.7 ± 3.8 mg∙m−2∙yr−1 in WS3, and 35.4 ± 3.6 mg∙m−2∙yr−1 in HSR. The increased secondary production of P. angulata was related to greater mean abundance and biomass in SFR; and the production/biomass ratio for this acidic stream was lower than for the other streams.


2017 ◽  
Vol 68 (7) ◽  
pp. 643 ◽  
Author(s):  
Chao Chen ◽  
Andrew Smith ◽  
Phil Ward ◽  
Andrew Fletcher ◽  
Roger Lawes ◽  
...  

Tedera (Bituminaria bituminosa var. albomarginata) has been proposed as an alternative perennial forage legume to lucerne in the mixed farming zone of Australia. Simulation of growth and production of tedera would be a useful tool for assessing its integration into Australian farming systems and agronomic and management options. This paper describes the development and testing of a model of the growth and development of tedera in Agricultural Production Systems Simulator (APSIM). The existing APSIM-Lucerne was modified to develop APSIM-Tedera. The key physiological parameters for tedera were obtained from the literature or by measuring and comparing the phenology and growth characteristics of tedera and lucerne in glasshouse experiments and partially from field experiments. The model was tested using data from a diverse range of soil and climatic conditions. Using the modelling approach, the production of tedera and lucerne was also assessed with long-term (1951–2015) weather data at Arthur River, Western Australia. Biomass simulations of tedera (n = 26, observed mean = 510 kg dry mass ha–1) explained 66% of the observed variation in field experiments (root mean square deviation = 212 kg dry mass ha–1). Long-term simulations of a 4-year pasture phase showed that more total annual biomass (5600 kg ha–1) would be obtained from lucerne than tedera if the pasture forage was harvested four times a year. Less biomass (400 kg ha–1) was also simulated for tedera in summer under this management. When the pasture forage was harvested when biomass was more than 2000 kg ha–1, tedera and lucerne produced similar accumulated biomass in the second (8000 kg ha–1), third (12 000 kg ha–1) and fourth (15 000 kg ha–1) years, but much less in the first 2 years for tedera. The model can be used for assessing tedera production, agronomic and management options in the Mediterranean climate of Australia. The present preliminary study indicates that tedera is not as effective as lucerne for total biomass production, but it may provide useful feed in situations where the summer-autumn feed gap is a major constraint to production. Further research is also necessary to determine the potential role of tedera in areas where lucerne is not well adapted.


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