scholarly journals Nature Conservation Against All? Aquatic Macrophyte De-Weeding – Cut or Conserve? A Stakeholder Analysis

2017 ◽  
Vol 54 ◽  
pp. 1-14 ◽  
Author(s):  
Vasco Brummer ◽  
Sandra Roth ◽  
Markus Röhl ◽  
Carsten Herbes

De-weeding of streams and lakes occurs in Germany on a widespread level, mostly to ensure water runoff and to provide flood protection. But de-weeding also affects a range of stakeholders, who have their own reasons to support or oppose it. For the list of stakeholders identified, see chapter 4. As part of a project analysing the feasibility of using water plant biomass as a substrate for biogas production, we conducted a multi-method stakeholder analysis to evaluate stakeholders’ opinions about de-weeding. The results show a preference of all stakeholders, except those identifying with nature conservation, for aquatic de-weeding. Our findings also point to a lack of communication between stakeholders, resulting in biased opinions of the stakeholders against other stakeholders and starting points for conflict.

Author(s):  
Bárbara Angélio Quirino ◽  
Franco Teixeira de Mello ◽  
Sabrina Deosti ◽  
Claudia Costa Bonecker ◽  
Ana Lúcia Paz Cardozo ◽  
...  

Abstract Habitat complexity is recognized to mediate predator–prey relationships by offering refuge or not. We investigated the availability of planktonic microcrustaceans and the diet of a planktivorous fish (Hyphessobrycon eques) at different levels (low, intermediate and high) of aquatic macrophyte biomass. Sampling was carried out in a river with low flow speed, located in a Neotropical floodplain. We collected fish and microcrustaceans in macrophyte stands with variations in biomass. There were no differences in microcrustacean density in the water among the levels of macrophyte biomass, but microcrustacean richness and diet composition of H. eques differed. Microcrustacean richness and trophic niche breadth of the planktivorous fish were higher in high biomass stands. There was high consumption of a small cladoceran species in low macrophyte biomass, which was replaced by larger species, such as copepods, in intermediate and high biomass. Thus, the selection of some species was different among the biomass levels. These results suggest that plant biomass plays an important role in the interaction between fish and microcrustaceans, and prey characteristics such as size, escape ability and energy value make them more or less subject to predation by fish according to habitat structuring.


2010 ◽  
Vol 101 (24) ◽  
pp. 9527-9535 ◽  
Author(s):  
Ewa Klimiuk ◽  
Tomasz Pokój ◽  
Wojciech Budzyński ◽  
Bogdan Dubis

2007 ◽  
Vol 98 (8) ◽  
pp. 1664-1669 ◽  
Author(s):  
V.K. Verma ◽  
Y.P. Singh ◽  
J.P.N. Rai

2022 ◽  
Author(s):  
Adedeji A. Adelodun ◽  
Temitope M. Olajire ◽  
Ochuko Mary Ojo

Using biomass as a renewable energy source has earned tremendous interest from researchers in recent decades, especially because the technology is environmentally benign. This article reviews the recent methods for generating biogas from water hyacinth (WH, Eichornia crassipes), arguably the world’s most evasive aquatic macrophyte. Therefore, various economic, environmentally benign, and renewable procedures that enhance biogas production from WH biomass are reviewed. WH has been co-digested with numerous waste types, including poultry droppings, municipal wastes, animal tissue wastes, pig wastes, cow dungs, etc., recording varying success degrees. Other studies focused on optimizing the operation parameters, such as mixing ratio, contact time, pH, temperature, organic loading rate, etc. We observed that most attempts to generate biogas from WH alone were not promising. However, when co-digested with other biomasses or wastes, WH either increases the process rate or improves the methane yield content. Also, the potential of WH as a phytoremdiator-cum-biogas source was investigated. This chapter provides mathematical models, scale-up installation models, and specific experimental results from various studies to guide future study plans toward optimizing CH4 generation from WH co-digestion.


In this paper three sustainable approaches are made in waste management option. Firstly primary treated domestic sewage is treated by aquatic macrophytes using duckweed, water hyacinth and water lettuce. Biochemical Oxygen Demand (BOD), Chemical Oxygen Demand (COD), Total Suspended Solids (TSS), Total Dissolved Solids (TDS), Phosphate, Nitrates are tested before and after. Result indicates in terms of water quality, almost all three plants shows same removal efficiencies. BOD and TSS removal efficiency is attained more than 95%. COD and TDS removal is reached upto 50% for almost all plants. Secondly the used aquatic macrophytes for wastewater treatment is again used for generation of biogas (water lettuce unit, duckweed unit, water lettuce unit). In addition to three aquatic macrophytes, sludge is collected from aquatic macrophyte unit for generation of biogas. Comparison is made with conventional cow dung biogas unit. Result indicates water lettuce and duckweed produce biogas at earlier stage itself and water hyacinth takes some time for starting of biogas production. This may be due to the structure and texture causes some time for decomposition. Sludge gives maximum biogas generation among all experimental setup. Also in this study cow dung did not give biogas more may be due to poor blend ratio of cow dung with water is one of the reason.


Bothalia ◽  
1992 ◽  
Vol 22 (2) ◽  
pp. 283-288 ◽  
Author(s):  
P. J. Weisser ◽  
A. K. Whitfield ◽  
C. M. Hall

Between 1979 and 1981, the submerged aquatic macrophyte vegetation in the Wilderness lakes died back significantly, and in some areas disappeared altogether. This study documents the senescent phase and describes the recovery of the plant populations between May 1982 and May 1983. In two lakes, namely Langvlei and Eilandvlei, the plant biomass approximately doubled between the winters of 1982 and 1983. Seasonal changes in species composition are documented and possible factors accounting for the collapse and recovery of the plant populations are discussed.


Forests ◽  
2020 ◽  
Vol 11 (3) ◽  
pp. 332
Author(s):  
Tomislav Laktić ◽  
Aleš Žiberna ◽  
Tina Kogovšek ◽  
Špela Pezdevšek Malovrh

Stakeholder participation has become an important driving force in policy decision-making and implementation, particularly in the nature conservation sector, where complex interactions and conflict of interest between stakeholders are common. A stakeholder analysis, which was complemented with a social network analysis, was used to examine the cooperation and conflict network between stakeholders, their institutions, and sectors in the case of the formulation of the Natura 2000 Management programme in Slovenia for the period 2015–2020 (PUN). Using data from a web survey (n = 167), cooperation and conflict networks were analysed while using degree centrality, indegree centrality, betweenness centrality, and blockmodeling. The results of the stakeholder analysis showed that the highest number of stakeholders that are involved in the participatory process of PUN was from the forestry and hunting sector, followed by the agriculture and nature conservation sector. The results of the cooperation network showed that the network is highly centralized, with only few institutions taking a central position in the PUN process (Institute for Nature Conservation, Ministry of Environment and Spatial Planning, Chamber of Agriculture and Forestry, Ministry of Agriculture, Forestry and Food, and the Slovenian Forest Service). Moreover, the nature conservation sector was, on average, a sector with the highest concentration of power. In addition, in the cooperation network, which was fragmented across sectors, there were institutions that belonged to the same sector, which tended to cooperate with each other. The analysis of the conflict network showed that institutions with a central position in the cooperation network also had a central role in the conflict network. In addition, conflicts between institutions more frequently appeared among institutions from different sectors. The exceptions were institutions from the fishery and water sector, as this sector seemed to have many conflicts within it. Based on a blockmodeling, four groups of institutions were identified according to their cooperation network (core institutions, semi-core institutions, semi-periphery institutions, and periphery institutions). Our finding suggested that the participatory process of formulating PUN needs to be improved in such a way that in the future various stakeholders, especially excluded local ones, are more actively involved and a balance of the power between the stakeholders involved achieved.


2016 ◽  
Vol 35 ◽  
pp. 785-794 ◽  
Author(s):  
Dipam Patowary ◽  
Helen West ◽  
Michèle Clarke ◽  
D.C. Baruah

Author(s):  
Ugwu Tochukwu Nicholas ◽  
Nwachukwu Augusta Anuli ◽  
Ogbulie Toochukwu Ekwutosi ◽  
Anyalogbu Ernest Anayochukwu

Enormous quantities of plant biomass are generated annually, as agricultural wastes. Lignocellulose is the main structural constituent of plants and represents the primary source of renewable organic matter on earth. This study was carried out to evaluate the lignocellulose composition, proximate and selected physicochemical characteristics of some selected plant-based substrates for biogas production. The substrates were: Corn cobs, Rice straw and Water hyacinth (Eichhorniacrassipes). They were collected, cut, dried for 72 hours at 320C, milled and subjected to hemicellulose, lignin and cellulose compositional analyses, using the standard Sox let extraction method. Standard methods were employed for proximate and physicochemical analyses. Results of the compositional evaluation showed that corn cob has the highest percentages of cellulose (42.0%), while extractives content was least (2.18%) in Rice straw. For the proximate analysis, the percentage carbohydrates (24.22) and ash (24.40) were highest in rice straw, while fat content  had the least values of 0.65%  recorded in corn cobs. The results of the physicochemical analysis showed that Rice straw had the highest values of TS (94.55%) and phosphorus (928.57mg/kg), Corn cob had the highest TVS (85.53%) and organic carbon (50.46%) while Water hyacinth recorded the highest Nitrogen content (2.33%). They are good substrates for energy generation, and lignocellulosic biomass holds a huge potential to meet the current energy demand of the modern world. The knowledge of the lignocellulosic composition of the biomass would help in choosing appropriate pretreatment measures to achieve better hydrolysis which would translate to higher biogas yield.


2019 ◽  
Vol 6 ◽  
pp. 37-41
Author(s):  
Yulia Karaeva ◽  
Svetlana Timofeeva

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