scholarly journals Evaluation of the conservation requirements of Trichoptera from the Tsitsikamma mountain streams in South Africa

Zoosymposia ◽  
2019 ◽  
Vol 14 (1) ◽  
pp. 151-164
Author(s):  
FERDINAND C. DE MOOR ◽  
TERENCE A. BELLINGAN
Keyword(s):  
Species Composition ◽  
Cool Temperature ◽  
Freshwater Species ◽  
Western Cape ◽  
Water Abstraction ◽  
Temperature Regimes ◽  
Strong Evaluation ◽  
Limiting Nutrient ◽  
Alkaline Conditions ◽  
The Subject

A four-season survey of Trichoptera between April 2008 and January 2009, from 20 sites in 11 rivers flowing off the Tsitsikamma mountains in the Eastern and Western Cape, collected 42,683 adults and 6741 larvae, comprising 48 species in 22 genera and 12 families. Trichoptera were the numerically dominant freshwater macroinvertebrate taxon. Of the species collected, 15 are recognised regional Cape Floristic Realm (CFR) endemics. Some specimens of Trichoptera that could not be recognised as described species are now the subject of further studies. Distinct differences between rivers, in terms of species composition of Trichoptera, were noted. The variation in species composition can be partially explained by the physicochemical and ecological attributes of the rivers surveyed. Anthropogenic disturbances were noted in most of the lower reaches of the rivers. The upper reaches of the rivers could be statistically grouped together and thus be considered as a unit for conservation. The highest diversity, 25 species, was recorded from the pristine upper reaches of the Bobbejaans River. An evaluation of conservation requirements identified a number of threats: increased loads of fine sediment and nutrients, higher water temperature regimes, and changes to pH, from the natural acid (pH < 5.5) to neutral or alkaline conditions. Changes in any of these would be detrimental to the survival of many of the endemic Trichoptera in the CFR, and all of these changes would be exacerbated by decreased water-flow volumes. It is thus important to limit the levels of water abstraction from these rivers: to ensure the maintenance of cool temperature and acidic pH regimes while limiting nutrient levels in the rivers. To maintain conservation of the lower reaches of the rivers it is recommended that an ecologically-functional continuity with upstream reaches is maintained to enable the occupation of all zones of the rivers with a diversity of CFR freshwater endemic species. Some CFR Trichoptera were selected as indicators of favourable conditions for the survival and maintenance of viable populations of other CFR-endemic freshwater species.

Sucrose accumulation in sugarcane is influenced by temperature and genotype through the carbon source - sink balance

2010 ◽  
Vol 61 (2) ◽  
pp. 111 ◽  
Author(s):  
N. G. Inman-Bamber ◽  
G. D. Bonnett ◽  
M. F. Spillman ◽  
M. H. Hewitt ◽  
D. Glassop
Keyword(s):  
Water Stress ◽  
Molecular Techniques ◽  
Clonal Variation ◽  
Sink Strength ◽  
Extension Rate ◽  
Cool Temperature ◽  
Sucrose Accumulation ◽  
Temperature Regimes ◽  
New Research ◽  
Source Sink

While substantial effort has been expended on molecular techniques in an attempt to break through the apparent ceiling for sucrose content (SC) in sugarcane stalks, molecular processes and genetics limiting sucrose accumulation remain unclear. Our own studies indicate that limiting expansive growth with water stress will enhance sucrose accumulation in both low- and high-sucrose clones. Sucrose accumulation was largely explained (72%) by an equation with terms for photosynthesis, plant extension rate (PER), and plant number. New research was conducted to determine if this simple model stands when using temperature rather than water stress to perturb the source–sink balance. We also applied a thinning treatment to test the proposal implicit in this equation that SC will increase if competition between plants for photo-assimilate is reduced. Four clones from a segregating population representing extremes in SC were planted in pots and subjected to warm and cool temperature regimes in a glasshouse facility. A thinning treatment was imposed on half the pots by removing all but 6 shoots per pot. Temperature as a means of reducing sink strength seemed initially to be more successful than water regime because PER was 43% lower in the cool than in the hot regime while photosynthesis was only 14% less. PER was a good indicator of dry matter allocation to expansive growth, limited by water stress but not by temperature, because stalks tended to thicken in low temperature. Thinning had little effect on any of the attributes measured. Nevertheless the clonal variation in plant numbers and the response of PER to temperature helped to explain at least 69% of the variation in sucrose accumulation observed in this experiment. Thus the earlier model for sucrose accumulation appeared to be valid for the effect on sucrose accumulation of both temperature and water stress on the source–sink balance. The next step is to include internodes in models of assimilate partitioning to help understand the limiting steps in sucrose accumulation from the basics of source–sink dynamics.

scholarly journals Source tracking of Enterococcus moraviensis and E. haemoperoxidus

2016 ◽  
Vol 15 (1) ◽  
pp. 41-49 ◽  
Author(s):  
Maja Taučer-Kapteijn ◽  
Wim Hoogenboezem ◽  
Remco Hoogenboezem ◽  
Sander de Haas ◽  
Gertjan Medema
Keyword(s):  
Species Composition ◽  
Shallow Aquifer ◽  
Source Tracking ◽  
Ionization Time ◽  
Water Abstraction ◽  
Faecal Samples ◽  
Enterococcus Spp ◽  
Drinking Water Production ◽  
Natural Dune ◽  
Faecal Indicators

Enterococci were detected occasionally in 100 L samples of water abstracted from a shallow aquifer in a natural dune infiltration area for drinking water production. Enterococcus moraviensis was the species most frequently identified in these samples. Because there are no existing reports of faecal sources of E. moraviensis and the closely related E. hemoperoxidus, this study aimed to find such sources of these two species in the dunes. Faecal samples from various animal species living in the vicinity of abstraction wells, were analysed for enterococci on Slanetz and Bartley Agar. From these samples, enterococci isolates (1,386 in total) were subsequently identified using matrix assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry. E. moraviensis was found in the faeces of geese, foxes and rabbits. Also, E. haemoperoxidus was isolated from goose faeces. Using hierarchical clustering, the species composition of Enterococcus spp. isolated from abstracted water formed one cluster with the species composition found in geese droppings. A sanitary survey supported the indication that feral geese may provide a substantial faecal load in particular parts of this dune infiltration area, close to the water abstraction system. This study confirms the faecal origin of E. moraviensis and E. haemoperoxidus from specific animals, which strengthens their significance as faecal indicators.

Decomposition products of cylindrospermopsin – a cyanotoxin produced by Raphidiopsis raciborskii (Woloszynska)

2019 ◽  
Vol 48 (3) ◽  
pp. 227-235 ◽  
Author(s):  
Michal Adamski ◽  
Paweł Żmudzki ◽  
Jan Bialczyk ◽  
Ariel Kaminski ◽  
Ewelina Chrapusta-Srebrny ◽  
...  
Keyword(s):  
High Temperature ◽  
Environmental Factors ◽  
Vibrio Fischeri ◽  
Freshwater Species ◽  
Decomposition Products ◽  
Structural Modifications ◽  
Toxicity Potential ◽  
Alkaline Conditions ◽  
Living Organisms ◽  
Guanidine Moiety

Abstract Toxins produced by cyanobacteria (cyanotoxins) and released into water have become a serious problem worldwide due to the increasing morbidity and mortality of living organisms they have caused. The ability to synthesize the cytotoxic alkaloid cylindrospermopsin (CYN) has been demonstrated in several freshwater species of cyanobacteria. CYN is highly chemically stable under environmental factors and decomposes only under alkaline conditions, where it forms derivatives. The toxicity potential of the decomposition products formed at pH 10 combined with high temperature (100°C) or UV-B irradiation (36 μmol m−2 s−1) has been research based on the crustacean Thamnocephalus platyurus (Thamnotoxkit FTM) and bacteria Vibrio fischeri (Deltatox® II) bioassays. This paper is a continuation and completion of our previous experiments and the obtained results showed that the applied conditions contributed to the decomposition of the CYN molecule to non-toxic products and its structural modifications by separating the uracil ring or/and the sulfate group from the tricyclic guanidine moiety, leading to a reduction in its toxicity. To the best of our knowledge, this is the first report describing the toxicity of CYN decomposition products formed under alkaline conditions combined with boiling temperature or UV-B irradiation.

THE BEHAVIOR OF THREE COLD-TOLERANT AND A STANDARD SOYBEAN VARIETY IN RELATION TO THE LEVEL AND THE DURATION OF A COLD STRESS

1980 ◽  
Vol 60 (3) ◽  
pp. 821-829 ◽  
Author(s):  
J. SCHMID ◽  
E. R. KELLER
Keyword(s):  
Cold Stress ◽  
Cold Tolerance ◽  
Growth Chamber ◽  
Cool Temperature ◽  
Federal Republic Of Germany ◽  
Average Growth ◽  
Cold Temperatures ◽  
Temperature Regimes ◽  
Cold Tolerant ◽  
The Stability

The cold tolerance of the varieties Gieso (Federal Republic of Germany), Amurskaja 41 (Russia), ISZ-7 and I-1 (Hungary) was investigated in growth chamber and greenhouse experiments. In the growth chamber trial, cool and cold temperatures reduced the grain yield of Gieso whereas ISZ-7 and I-1 increased their yields from the high temperature level to the coldest one. Amurskaja 41 had about the same yield in the warm and cool temperature regimes but in the coldest treatment, yields decreased compared with those of Gieso. The high quality of ISZ-7 and I-1 to compensate for stress periods as compared with Gieso and also with Amurskaja 41 is reflected in the average growth rate, the flower and pod formation and the dry matter production per plant. In the greenhouse experiment, duration of a cold stress at vegetative stages V1 and V3 and at the beginning of flowering was investigated. All tested varieties were able to compensate for cold stress of 10 days whereas only ISZ-7 and I-1 showed good yields under a long period of stress. These more cold tolerant varieties were particularly able to make good use of subsequent higher temperatures as expressed by the grain weight per degree Celsius. The stability of harvest index is also an important factor in cold tolerance investigations.

Observations on the life-history and ultrastructure of the marine choanoflagellate Choanoeca perplexa Ellis

1977 ◽  
Vol 57 (2) ◽  
pp. 285-301 ◽  
Author(s):  
Barry S. C. Leadbeater
Keyword(s):  
Life History ◽  
Electron Microscope ◽  
Marine Species ◽  
Freshwater Species ◽  
Relative Ease ◽  
Ultrastructural Studies ◽  
Modern Methods ◽  
The Subject ◽  
Stephanoeca Diplocostata ◽  
Whole Mounts

In recent years the external morphology of marine choanoflagellates has been the subject of close scrutiny. This is a result of the attention given to marine nanoplankton, of which choanoflagellates are a part, and the relative ease with which choanoflagellates with loricae of costal construction can be observed in shadowcast whole mounts with an electron microscope. However, detailed ultrastructural studies of choanoflagellate protoplasts have been limited to one freshwater species Codosiga botrytis (Ehr.) Saville-Kent (Petersen & Hansen, 1954; Fjerdingstad, 1961; Hibberd, 1975) and four marine species Salpingoeca pelagica Laval (Laval, 1971), Stephanoeca diplocostata Ellis (Leadbeater & Manton, 1974), Savillea micropora (Norris) Leadbeater (Leadbeater, 1974) and Codosiga gracilis James-Clark (Leadbeater & Morton, 1974b). Of these only the recent studies by Hibberd (1975), Laval (1971), Leadbeater & Manton (1974), Leadbeater (1974) and Leadbeater & Morton (1974b) contain micrographs of material processed by modern methods.

Phycological studies in lakes Ontario, Erie, Huron, and Superior

1982 ◽  
Vol 60 (9) ◽  
pp. 1837-1858 ◽  
Author(s):  
M. Munawar ◽  
I. F. Munawar
Keyword(s):  
Species Composition ◽  
Great Lakes ◽  
Primary Concern ◽  
Carbon 14 ◽  
The Past ◽  
The Subject ◽  
Processing Techniques ◽  
Canadian Research

An indepth phycological comparison is presented for lakes Ontario, Erie, Huron, and Superior, based on extensive lake-wide surveys carried out during the past 12 years. This comparison was achieved by the application of standard and consistent identification, enumeration, and data-processing techniques. The resulting species composition data are voluminous and present a broad picture of the phytoplankton assemblage. Our data base has enabled us to assess the long-term floristic changes, knowledge of which is lacking in the Great Lakes. The species composition reflects more or less the current trophic status of these lakes. The preponderance of nannoplankton and phytoflagellates is the subject of our current experimental research, which includes the fractionation of chlorophyll a and carbon-14 uptake, toxicity studies of heavy metals upon various size fractions of algae, and the role of microalgae and ultraplankton in the transfer of contaminants via zooplankton grazing. The need for phycological research in the Great Lakes is expanding with decreasing eutrophication and the increasing problems of contaminants. The recovery, rehabilitation, and preservation of these vital freshwaters are the primary concern of the continuing Canadian research program in the Great Lakes.

Ecology of Cladonia lichens. I. Preliminary assessment of the ecology of terricolous lichen–moss communities in Ontario and Wisconsin

1974 ◽  
Vol 52 (1) ◽  
pp. 55-64 ◽  
Author(s):  
Martin J. Lechowicz ◽  
Michael S. Adams
Keyword(s):  
Environmental Gradients ◽  
Principal Component ◽  
Geographic Region ◽  
Ground Layer ◽  
Subsequent Paper ◽  
Pine Barrens ◽  
Temperature Regimes ◽  
Ordination Techniques ◽  
The Subject ◽  
Terricolous Lichen

Principal component and Bray and Curtis ordination techniques were used to explore the ecology of lichen–moss ground-layer communities in Ontario and Wisconsin. The Ontario data included thirty-nine 100-m2 stands from a large geographic region; lichen and moss relations along macroscale environmental and successional gradients were considered. Species relations along gradients of moisture and exposure were recognized. The Wisconsin data included one hundred sixty-six 0.5-m2 quadrats from a single site in the Wisconsin Pine Barrens; species relations along microscale environmental gradients were examined. Gradients related to moisture, light, and temperature regimes were recognized. The ordinations provided a graphic display of the ground-layer lichen–moss community ecology and offered a basis for further work on the comparative autoecology of various Cladonia lichens. Cladonia mitis, C. rangiferina, and C. uncialis, the subject of a subsequent paper in this series, were found to be similar in the macroscale but separated in the microscale ordinations.

scholarly journals TEMPERATURE IS A KEY REGULATOR OF GROWTH AND FLOWERING IN PROTEA NERIIFOLIA AND PROTEA CYNAROIDES

HortScience ◽  
1992 ◽  
Vol 27 (6) ◽  
pp. 649g-649
Author(s):  
Steven Dupee ◽  
Peter Goodwin
Keyword(s):  
Field Data ◽  
Floral Development ◽  
Important Determinant ◽  
Stem Diameter ◽  
Flower Initiation ◽  
Cool Temperature ◽  
Floral Initiation ◽  
Vegetative Phase ◽  
Reproductive Phase ◽  
Temperature Regimes

The strategy of this study was to determine the period of floral initiation for both species and then to determine the critical regulator(s) of flower initiation and floral development. Plants grown under different temperature regimes gave best shoot extension and flower initiation at temperatures with 10°C night and 15 to 25°C day. Field data from four locations showed a correlation of time of flower initiation and temperatures over the same range. Temperature is an important determinant of the vegetative flush period of both species. The stem diameter of all shoots is a consequence of the vegetative flush growth and in turn is well correlated with flower initiation. Plants given day temperatures of 20°C or above remain in the vegetative phase. Flower abortions in Protea neriifolia and reversions from floral to vegetative shoots in Protea cynaroidesresult from high day temperatures. Daylength was not found to be critical for flower initiation. A cool temperature period acts as a control to change shoots from the vegetative to reproductive phase.

Conservation Science Statement. The demise of New Zealand's freshwater flora and fauna: a forgotten treasure

2016 ◽  
Vol 22 (2) ◽  
pp. 110 ◽  
Author(s):  
Emily S. Weeks ◽  
Russell G. Death ◽  
Kyleisha Foote ◽  
Rosalynn Anderson-Lederer ◽  
Michael K. Joy ◽  
...  
Keyword(s):  
Best Management Practices ◽  
Water Policy ◽  
Management Practices ◽  
National Policy ◽  
Freshwater Ecosystems ◽  
Policy Statement ◽  
Freshwater Species ◽  
Freshwater Biodiversity ◽  
Water Abstraction ◽  
Endemic Flora

New Zealand’s freshwater ecosystems support a diverse and unique array of endemic flora and fauna. However, the conservation of its freshwater biodiversity is often overlooked in comparison to terrestrial and marine environments, and is under increasing threat from agricultural intensification, urbanisation, climate change, invasive species, and water abstraction. New Zealand has some of the highest levels of threatened freshwater species in the world with, for example, up to 74% of native freshwater fish listed as endangered or at risk. Threatened species are often discounted in water policy and management that is predominantly focussed on balancing water quality and economic development rather than biodiversity. We identify six clear actions to redress the balance of protecting New Zealand’s freshwater biodiversity: 1. change legislation to adequately protect native and endemic fish species and invertebrates, including those harvested commercially and recreationally; 2. protect habitat critical to the survival of New Zealand’s rare and range-restricted fish, invertebrate and plant freshwater species; 3. include river habitat to protect ecosystem health in the National Objectives Framework for the National Policy Statement for freshwater; 4. establish monitoring and recovery plans for New Zealand’s threatened freshwater invertebrate fauna; 5. develop policy and best management practices for freshwater catchments in addition to lakes and rivers to also include wetlands, estuaries, and groundwater ecosystems; and 6. establish, improve, and maintain appropriately wide riparian zones that connect across entire water catchments. We have published these recommendations as a scientific statement prepared for the Oceania Section of the Society for Conservation Biology to facilitate communication of our thoughts to as wide an audience as possible (https://conbio.org/images/content_groups/Oceania/Scientific_Statement_1_.pdf, accessed 8 February 2016).

CHANGES IN THE TERRESTRIAL SPIDER FAUNA (ARACHNIDA: ARANEAE) OF A NORTH GERMAN RAISED BOG DISTURBED BY HUMAN INFLUENCE. 1964–1965 AND 1986–1987: A COMPARISON

1994 ◽  
Vol 126 (S169) ◽  
pp. 61-71 ◽  
Author(s):  
Hans-Bert Schikora
Keyword(s):  
Species Composition ◽  
Indicator Species ◽  
Pitfall Trap ◽  
Species Level ◽  
Human Influence ◽  
Raised Bog ◽  
Spider Species ◽  
Hydrological Changes ◽  
The Subject ◽  
Most Probable Explanation

AbstractThe terrestrial spider fauna of a North German bog relict, initially examined in a pitfall trap study in 1964–1965, was the subject of a similar examination 22 years later. Between the investigations the bog, which was still in a quite pristine state, had considerably changed its ecological character due to progressive draining. Sixty-eight spider species were collected. Many of them are characteristic for bogs, but none can be regarded as bog-specific. On a general species level no clear clues about consequences of biotope changes could be ascertained; 81% of the former species were found again.The most informative data are provided by species composition and abundance of the more prevalent spider species. In 1964–1965 the spider fauna was clearly dominated by photophilous species, many of them additionally preferring wet or moist biotopes. Twenty-two years later the proportion of photophilous species had decreased in favour of more skotophilous species.The scale of changes in biotope characters is regarded as the most probable explanation for this phenomenon, especially the increase of "shrubbiness" in vegetation and the nearly total loss of peatmosses. The spider Antistea elegans (Blw.), Hahniidae, is discussed as a possible indicator species for monitoring hydrological changes in bog biotopes.

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