Marine social–ecological responses to environmental change and the impacts of globalization     

R Ian Perry  Rosemary E Ommer  Manuel Barange  Svein Jentoft  Barbara Neis  U Rashid Sumaila 《Fish and Fisheries》2011,12(4):427-450

Marine social–ecological systems consist of interactive ecological and human social elements so that changes in ecological systems affect fishing‐dependent societies and vice versa. This study compares the responses of marine ecological and fishing‐dependent systems to environmental change and the impacts of globalization, using four case‐studies: NE Atlantic (Barents Sea), NW Atlantic (Newfoundland), SE Atlantic (Namibia) and the equatorial Atlantic (Ghana). Marine ecological systems cope with short‐time changes by altering migration and distribution patterns, changing species composition, and changing diets and growth rates; over the longer term, adaptive changes lead to increased turn‐over rates and changes in the structure and function of the system. Fishing communities cope with short‐term change through intensification and diversification of fishing, migration and ‘riding out the storm’. Over the longer term, adaptive changes in policy and fisheries governance can interact with social–ecological change to focus on new fisheries, economic diversification, re‐training, out‐migration and community closures. Marine social–ecological systems can ultimately possess rapid adaptive capacity in their ecological components, but reduced adaptive capacity in society. Maintaining the diversity of response capabilities on short and longer time scales, among both ecological and human fishing systems, should be a key policy objective. The challenge is to develop robust governance approaches for coupled marine social–ecological systems that can respond to short‐ and long‐term consequences of global change.  相似文献   

Dietary Aspilia mossambicensis and Azadirachta indica supplementation alter gonadal characteristics and histology of juvenile Nile tilapia (Oreochromis niloticus)     

Imani Benedict Kapinga  Samwel Mchele Limbu  Nazael Amos Madalla  Wahabu Hamisi Kimaro  Faith Philemon Mabiki  Hieromin Amon Lamtane  Rashid Adam Tamatamah 《Aquaculture Research》2019,50(2):573-580

The use of medicinal plants to control reproduction in aquaculture have recently received considerable attention because they are biodegradable, safe, effective and locally available. However, information on their effects on gonadal characteristics and histological features in fish is currently limited. The present study evaluated the gonadal characteristics and histological changes of Nile tilapia, Oreochromis niloticus gonads fed on Aspilia plant, Aspilia mossambicensis and Neem tree, Azadirachta indica. Juvenile fish were fed diets supplemented with four doses (1.0, 2.0, 4.0 and 8.0 g/kg diet) of A. mossambicensis or A. indica leaf powders at 3% of their body weight daily for 90 days to examine absolute fecundity (AF), relative fecundity, gonadosomatic index (GSI) and histology of gonads. The antifertility phytocompounds in the two plants were quantified by using standard methods. Results indicated that, all doses of A. indica and A. mossambicensis used reduced significantly AF and GSI values (p < 0.05). Dose‐dependent histological alterations of gonads were noticed in both plants starting from doses of 2.0 g/kg in males and 4.0 g/kg in females. The highest percentages of total flavonoids (23.7%) and alkaloids (14.2%) were obtained from A. indica ethanol extract (p < 0.05). Taken together, dietary supplementation with A. mossambicensis and A. indica leaf powders alter gonadal characteristics of O. niloticus and histology triggered by alkaloids and flavonoids. Farmers interested in using the two plants to control prolific breeding should limit the dose inclusion to 2 g/kg to avoid severe effects on fish testis and ovaries.  相似文献   

Pig manure digestate-derived biochar for soil management and crop cultivation in heavy metals contaminated soil     

Muhammad Ayaz  Urte Stulpinaite  Dalia Feiziene  Vita Tilvikiene  Kashif Akthar  Edita Baltrėnaitė-Gedienė  Nerijus Striugas  Urooj Rehmani  Sahib Alam  Rashid Iqbal  Monika Toleikiene  Modupe Doyeni 《Soil Use and Management》2022,38(2):1307-1321

Management of heavy metal-contaminated soil under drought and other harsh hydrological conditions is critical for protecting soil ecosystem services. In this study, we examined the effect of pig manure digestate-derived biochar as a soil amendment (15 t ha⁻¹) with N fertilizer (180 kg ha⁻¹) on soil and plant heavy metal levels and nutrient availability under various moisture regimes (optimal moisture ~15%, drought condition ≤5%, and flooded condition ≥35% wt.). It was observed that biochar applications significantly decreased heavy metals in the spring wheat plants, lowering Cr by 90%, Ni by 50%, Cd by 9% and Pb by 34% compared to non-biochar (control) treatments. However, the pig digestate-derived biochar increased heavy metals in soil under all moisture regimes, increasing soil Cr by 21%, Ni by 43%, Cu by 55%, Zn by 70%, and Pb by 12%. The availability of macroelements also increased with the biochar applications under the optimum moisture regimes in both soil and plants, increasing Mg²⁺ by 11%, P by 4%, K⁺ by 50%, and Ca²⁺ by 56% in the soil, and Mg²⁺ by 13%, P by 69%, K⁺ by 29, and Ca²⁺ by 39% in plants. Biochar addition also improved chlorophyll fluorescence (CF) levels in the crop for the entire season (12^th to 62^nd day) and the aboveground crop biomass and dry matter contents both increased. Consequently, the use of pig manure digestate-derived biochar with N fertilizer under normal moisture conditions was able to reduce heavy metal availability to plants and thus could be used in contaminated soils to maintain better crop growth and development.  相似文献