scholarly journals Anthropogenic Stressors in Upland Rivers: Aquatic Macrophyte Responses. A Case Study from Bulgaria

Plants ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 2708
Author(s):  
Gana Gecheva ◽  
Karin Pall ◽  
Milcho Todorov ◽  
Ivan Traykov ◽  
Nikolina Gribacheva ◽  
...  

Upland rivers across Europe still exhibit undisturbed conditions and represent a treasure that we cannot afford to lose. We hypothesize that the combination of pristine and modified conditions could demonstrate biological responses along the stressor gradients. Thus, the response of aquatic macrophyte communities to anthropogenic stressors along upland rivers in Bulgaria was studied. Six stressors were selected out of 36 parameters grouped into hydromorphological, chemical variables and combined drivers (catchment land use). The stressors strongly affected species richness on the basis of biological type (bryophytes vs. vascular plants) and ecomorphological type (hydrophytes vs. helophytes). Hydrological alteration expressed by the change of the river’s base flow and altered riparian habitats has led to a suppression of bryophytes and a dominance of riverbank plant communities. Seventy-five percent of mountain sites were lacking bryophytes, and the vegetation at semi-mountainous sites was dominated by vascular plants. It can be concluded that hydropeaking, organic and inorganic pollution, and discontinuous urban structures caused important modifications in the aquatic macrophyte assemblages. Macrophyte abundance and the biological and ecomorphological type of aquatic macrophytes reflect multi-stressor effects in upland rivers.

2013 ◽  
Vol 21 (2) ◽  
pp. 153-162
Author(s):  
Wang Guohong ◽  
Wang Xiaoping ◽  
Zhang Weikang ◽  
Li He ◽  
Du Lianhai ◽  
...  

The Holocene ◽  
2016 ◽  
Vol 27 (5) ◽  
pp. 651-664 ◽  
Author(s):  
Krystyna Milecka ◽  
Grzegorz Kowalewski ◽  
Barbara Fiałkiewicz-Kozieł ◽  
Mariusz Gałka ◽  
Mariusz Lamentowicz ◽  
...  

Wetlands are very vulnerable ecosystems and sensitive to changes in the ground water table. For the last few thousand years, hydrological balance has also been influenced by human activity. To improve their cropping features, drainage activity and fertilizing were applied. The drainage process led to an abrupt change of environment, the replacement of plant communities and the entire ecosystem. The problem of carbon sequestration is very important nowadays. A higher accumulation rate is related to higher carbon accumulation, but the intensity of carbon sequestration depends on the type of mire, habitat, and climatic zone. The main aim of this article was an examination of the changes in poor-fen ecosystem during the last 200 years in relation to natural and anthropogenic factors, using paleoecological methods (pollen and macrofossils). The second aim was a detailed investigation of the sedimentary record to aid our understanding of carbon sequestration in the poor fen of temperate zone. This case study shows that fens in temperate zones, in comparison with boreal ones, show higher carbon accumulation rates which have been especially intensive over the last few decades. To reconstruct vegetation changes, detailed palynological and macrofossil analyses were done. A 200-year history of the mire revealed that it was influenced by human activity to much degree. However, despite the nearby settlement and building of the drainage ditch, the precious species and plant communities still occur.


Author(s):  
D. N. Tiunov ◽  
◽  
E. G. Efimik ◽  

The problem of invasion of Sosnowsky hogweed (Heracleum sosnowskyi Manden.) In the Lipovaya Gora SPNA in Perm is considered. A map of distribution of hogweed cenopopulations in the protected area is presented. The results of the influence of the invasion of Sosnovsky hogweed on the biodiversity of vascu-lar plants of some plant communities are presented. It was revealed that the invasion of hogweed into phytocenoses of the Lipovaya Gora protected area leads to a decrease in the biodiversity of vascular plants by about 26.4% (up to 12 plant species). The ways of introduction of cow parsnip into the communities of the protected area are considered. High seed productivity, high projective cover, reaching in some cases 100%, high phytomass, the presence of dormant seeds, rapid development in spring, and high anthropo-genic load on the territory determine the rapid spread of H. sosnowskyi.


Author(s):  
Saed Khayat

Possible factors that play a role in restoring a flow regime that supports a healthy environment were identified for Wadi Zomar, Palestine. The hydrograph shows that threshold discharges for bed drying are less than 0.14 m3/s, bar formation is less than 0.4 ms/s and floodplain inundation events are over 3 m3/s. The HEC-RAS model suggests a continuous discharge throughout the year that maintains the base flow in the range of 0.5 m3/s. The model suggests that the restoration process is controlled by two main factors: role of sufficient flow and flood inundation frequency


2000 ◽  
Vol 60 (1) ◽  
pp. 83-92 ◽  
Author(s):  
A. F. M. CAMARGO ◽  
E. R. FLORENTINO

In this paper we evaluated the population dynamics and obtained estimates of the net primary production of the aquatic macrophyte Nymphaea rudgeana in an arm of the Itanhaém River (São Paulo State, Brazil). This species presents, in the studied area, a broad seasonal variation of biomass. As from November (13.1 g DW/m²) we observed a gradual increase of biomass that reached a maximum in February (163.1 g DW/m²). Then, the biomass decreased, maintaining low levels until a new growth period. The reduction of biomass is associated to the development of floating aquatic macrophytes (Pistia stratiotes and Salvinia molesta) and, subsequently to environmental factors (higher salinity values) that are unfavorable to their development. The net primary production of N. rudgeana was estimated from the biomass data, and the annual productivity value was estimated between 3.02 and 3.82 t/ha/year.


2018 ◽  
Vol 45 (12) ◽  
pp. 2718-2729 ◽  
Author(s):  
Hong Qian ◽  
Tao Deng ◽  
Jan Beck ◽  
Hang Sun ◽  
Cui Xiao ◽  
...  

2012 ◽  
Vol 21 ◽  
pp. 49-61 ◽  
Author(s):  
Ken Sterrett ◽  
Mark Hackett ◽  
Declan Hill

2018 ◽  
Vol 16 ◽  
pp. e00460 ◽  
Author(s):  
Bo Liu ◽  
Mei Zhang ◽  
W. Rainer Bussmann ◽  
Hui-ming Liu ◽  
Ying-ying Liu ◽  
...  

2007 ◽  
Vol 53 (3) ◽  
pp. 192-195 ◽  
Author(s):  
Takehiro Sasaki ◽  
Tomoo Okayasu ◽  
Yasuhito Shirato ◽  
Jamsran Undarmaa ◽  
Kazuhiko Takeuchi

Sign in / Sign up

Export Citation Format

Share Document