scholarly journals Does natural selection organize ecosystems for the maintenance of high productivity and diversity?

2002 ◽  
Vol 357 (1421) ◽  
pp. 709-718 ◽  
Author(s):  
Egbert Giles Leigh ◽  
Geerat Jacobus Vermeij

Three types of evidence suggest that natural ecosystems are organized for high productivity and diversity: (i) changes not previously experienced by a natural ecosystem, such as novel human disturbances, tend to diminish its productivity and/or diversity, just as ‘random’ changes in a machine designed for a function usually impair its execution of that function; (ii) humans strive to recreate properties of natural ecosystems to enhance productivity of artificial ones, as farmers try to recreate properties of natural soils in their fields; and (iii) productivity and diversity have increased during the Earth's history as a whole, and after every major biotic crisis. Natural selection results in ecosystems organized to maintain high productivity of organic matter and diversity of species, just as competition among individuals in Adam Smith's ideal economy favours high production of wealth and diversity of occupations. In nature, poorly exploited energy attracts more efficient users. This circumstance favours the opening of new ways of life and more efficient recycling of resources, and eliminates most productivity–reducing ‘ecological monopolies’. Ecological dominants tend to be replaced by successors with higher metabolism, which respond to more stimuli and engage in more varied interactions. Finally, increasingly efficient predators and herbivores favour faster turnover of resources.

2021 ◽  
pp. 014459872110310
Author(s):  
Min Li ◽  
Xiongqi Pang ◽  
Guoyong Liu ◽  
Di Chen ◽  
Lingjian Meng ◽  
...  

The fine-grained rocks in the Paleogene Shahejie Formation in Nanpu Sag, Huanghua Depression, Bohai Bay Basin, are extremely important source rocks. These Paleogene rocks are mainly subdivided into organic-rich black shale and gray mudstone. The average total organic carbon contents of the shale and mudstone are 11.5 wt.% and 8.4 wt.%, respectively. The average hydrocarbon (HC)-generating potentials (which is equal to the sum of free hydrocarbons (S1) and potential hydrocarbons (S2)) of the shale and mudstone are 39.3 mg HC/g rock and 28.5 mg HC/g rock, respectively, with mean vitrinite reflectance values of 0.82% and 0.81%, respectively. The higher abundance of organic matter in the shale than in the mudstone is due mainly to paleoenvironmental differences. The chemical index of alteration values and Na/Al ratios reveal a warm and humid climate during shale deposition and a cold and dry climate during mudstone deposition. The biologically derived Ba and Ba/Al ratios indicate high productivity in both the shale and mudstone, with relatively low productivity in the shale. The shale formed in fresh to brackish water, whereas the mudstone was deposited in fresh water, with the former having a higher salinity. Compared with the shale, the mudstone underwent higher detrital input, exhibiting higher Si/Al and Ti/Al ratios. Shale deposition was more dysoxic than mudstone deposition. The organic matter enrichment of the shale sediments was controlled mainly by reducing conditions followed by moderate-to-high productivity, which was promoted by a warm and humid climate and salinity stratification. The organic matter enrichment of the mudstone was less than that of the shale and was controlled by relatively oxic conditions.


2018 ◽  
Vol 100 (4) ◽  
pp. 745-766
Author(s):  
Lillian C. Woo

In the last fifty years, empirical evidence has shown that climate change and environmental degradation are largely the results of increased world population, economic development, and changes in cultural and social norms. Thus far we have been unable to slow or reverse the practices that continue to produce more air and water pollution, soil and ocean degradation, and ecosystem decline. This paper analyzes the negative anthropogenic impact on the ecosystem and proposes a new design solution: ecomimesis, which uses the natural ecosystem as its template to conserve, restore, and improve existing ecosystems. Through its nonintrusive strategies and designs, and its goal of preserving natural ecosystems and the earth, ecomimesis can become an integral part of stabilizing and rehabilitating our natural world at the same time that it addresses the needs of growing economies and populations around the world.


2021 ◽  
Vol 9 (11) ◽  
pp. 422-430
Author(s):  
Achoh Mardochee Ephraim ◽  
◽  
Agadjihouede Hyppolite ◽  
Gangbe Luc ◽  
Aizonou Romaric ◽  
...  

The present study aim to estimate the ratio of aquaculture in the phosphorus and nitrogen concentrations determined in the Toho - Todougba lagoons. For this purpose, the two lagoons were subdivided into 7 stations for the determination of phosphorus and nitrogen concentrations in the water column. Production data from 2017 to 2019 were collected from the Direction of the Ficheries Production and from the literature. Data for 2020 were collected directly from fish farmers. Annual tilapia production was estimated by year and the amounts of phosphorus and nitrogen released from aquaculture are deduced based on the ratio of Montanhini Neto & Ostrensky (2013). The concentration of each of these nutrients was estimated by station and compared to the concentration determined by laboratory analysis of the water. This methodology shows that the amount of phosphorus and nitrogen released to the environment varies from 0.49 mg/L to 0.18 mg/L for phosphorus and from 1.53 mg/L to 0.58 mg/L for nitrogen. The lowest values are obtained in 2020 and differ significantly from the other years (p <0.05). The quantity of phosphorus discharged is higher at the high production stations (Tonon 0.20 mg/L and Lokohoue 0.11 mg/L). Some of this is stored in the sediment. The nitrogen generated by aquaculture is significantly lower than the average determined in water (p <0.05). However, the concentration determined is still related to the amount of organic matter released due to aquaculture. Although aquaculture is not the only source of nutrient release to water, strategies for aquaculture with less nutrient release should be determined.


Author(s):  
Linus Takandare ◽  
Pamela Mercy Papilaya

Background: Mangrove forests are one of the unique natural ecosystems with high ecological value. Mangrove ecosystems are one of the areas with high productivity because there are litter and decomposition of litter and detritus occurs. This study was conducted to determine the association between gastropods and mangrove plants. Method: Research on gastropod association with mangrove plants in the coastal waters of Tiouw Village and Haria Village was conducted in January 2018. Results: This study found from gastropods 6 species namely variabilis strombus, microurceus strombus, Nassarius luridus, Strombus urceus, Cypraea annulus, Strombus, Strombus, Nerita squamulata. From the mangrove plants, 10 species were found: Avicennia eucalyptifolia, Avicennia lanata, Bruguiera sexangula, Rhizophora apiculata, Bruguiera hainessi, Aegiceras floridum R, Aegiceras curniculatum L, Bruguiera palviflora, Bruguiera exaristafa, Ceriops tagal. Conclusion: Association values ​​ranged from 0.741-0.9773 with positive and negative types. This means that both types of seagrass are often found together or not found together in the observation location


Author(s):  
Thomas S. Bianchi

In this chapter the general processes involved in controlling production and transformation of organic matter will be discussed as well as some of the associated stoichiometric changes of a few key biological elements (e.g., C, N, P, S). Stoichiometry is defined as the mass balance of chemical reactions as they relate to the law of definite proportions and conservation of mass (Sterner and Elser, 2002). For example, if we examine the average atomic ratios of C, N, and P in phytoplankton we see a relatively consistent ratio of 106:16:1 in most marine species. This is perhaps the best example of applied stoichiometric principles in natural ecosystems and is derived from the classic work of Alfred C. Redfield (1890–1983) (Redfield, 1958; Redfield et al., 1963). More specifically, Redfield compared the ratios of C, N, and P of dissolved nutrients in marine waters to that of suspended marine particulate matter (seston) (essentially phytoplankton) and found straight lines with equal slopes (figure 8.1; Redfield et al., 1963). This relationship suggested that marine biota were critical in determining the chemistry of the world ocean, clearly one of the most important historical findings linking chemical and biological oceanography (Falkowski, 2000). Moreover, the Redfield ratio has been further validated with recent data using improved analytical techniques (Karl et al., 1993; Hoppema and Goeyens, 1999). Other work has shown that there are predictable deviations from the Redfield ratio across a freshwater to open ocean marine gradient (figure 8.2; Downing, 1997). For example, N-to-P ratios in estuaries have commonly been shown to be lower and/or higher than the predicted Redfield ratio because of denitrification and anthropogenic nutrient enrichment processes, respectively. Inputs of vascular plant organic matter (e.g., mangroves, salt marshes, seagrasses) to estuarine systems presents another problem in causing deviations of C:N:P from the Redfield ratio. Vascular plants have been shown to deviate from this ratio in part because of relatively high amounts of C and N compared to algae due to a higher abundance of structural support molecules (e.g., cellulose, lignin) and defense antiherbivory (secondary) compounds (e.g., tannins), respectively (Vitousek et al., 1988).


Energies ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 6224
Author(s):  
Kosuke Mori ◽  
Tomohiro Tabata

This study aims to develop a comprehensive method for evaluating the environmental cost/benefits of photovoltaic (PV) solar plant installation versus conserving natural ecosystems. First, the positive and negative impacts of installing PV solar plants in regions with natural ecosystems are reviewed. For focus and quantification, climate change mitigation and economic benefit were considered as benefits, and the loss of carbon sinks and biodiversity as well as disaster risk were considered as negatives. These items were also integrated as external costs using a life-cycle assessment method, and a ratio of positive versus negative impacts (P/N ratio) was developed, as part of our evaluation. The method was applied to a case study in Hyogo Prefecture, Japan, where 361 large PV solar plants have been installed in areas that previously supported natural ecosystems. Prior to the PV installation, 25.5% of the plants were cleared from the natural ecosystem. Consequently, the annualized benefits (costs) for these Hyogo plants were estimated to be 101.16 (73.88) million USD, which yielded a P/N ratio of 1.37, indicating that their benefits outweighed their costs. An economic benefit was found to be one of the parameters that significantly influenced the P/N ratio.


Author(s):  
Songyan Li ◽  
Meng Li ◽  
Guoxi Wang ◽  
Xiaolei Sun ◽  
Beidou Xi ◽  
...  

Abstract Background Exploration of composition and chemical characteristics of soil dissolved organic matter (DOM) is significant to understand its biogeochemical role in terrestrial ecosystems. A total of 43 cropped and 16 natural soils (0–20 cm) under four soil types (cinnamon, chernozem, red and paddy soils) across China were collected to investigate the spectral characteristics of DOM using UV–Vis and 3D-EEM spectroscopy. Results The chernozem soils exhibited the highest aromaticity and humification degree among the four soil types. Ranges of biological index (BIX, 0.53–1.17) and fluorescence index (FI, 1.55–2.10) were found in the investigated DOM, showing joint contribution from allochthonous and autochthonous sources. Higher BIX and FI in the DOM of the paddy and red soils indicated a greater reliance on autochthonous sources for these two soil types. The cropped soils showed no significant differences in chemical characteristics and sources from the natural soils for the cinnamon, chernozem and red soils. UVA (16.2–47.9%) and UVC fulvic-like substances (15.4–40.5%) were the prevailing DOM components, which were highest in the chernozem soils. Additionally, the cropped soils had a higher proportion of humic-like substances than the natural soils in the DOM. Conclusions Both soil type and land-use strongly affected the chemical characteristics of soil DOM, but only soil type had an impact on the DOM composition for the collected soils. These findings may contribute to the prediction of the biochemical behavior of soil DOM under different soil types and land-uses in terrestrial ecosystems.


2020 ◽  
Vol 8 (3) ◽  
pp. 737
Author(s):  
Maria Inês Diel ◽  
Alessandro Dal’Col Lúcio ◽  
Denise Schmidt ◽  
Marcos Vinícius Marques Pinheiro ◽  
Tiago Olivoto ◽  
...  

The great economic importance attributed to strawberry cultivation raises the interest in cultivars of high productivity and superior fruit quality. The quality of fruit is the most impacting factor for the strawberry marketing, but selecting genotypes that combine high production and high fruit quality has been a difficult task. The objective of this study was to determine the linear relationships between phenological, quality and production variables of strawberry aiming at identifying potential variables for indirect selection in future selection processes of strawberry genotypes. A trial was conducted in a randomized block design with two cultivars and two transplant origins, grown in four types of substrate. Fifteen variables, including phenological, productive and fruit quality-related variables were assessed. The selected variables explained 45.2 and 39.1 % for PC1 and PC2 respectively, totaling 84.3 % of the total variance of the variables in the PCA, and indicated important relationships between the variables, and a path analysis revealed success for indirect selection of total mass of fruits based on the total number of fruits (0.81413). Changes in crop management that reduces the period between planting date and full flowering may be an alternative to increase the production of strawberry and provide fruits with higher quality.


Author(s):  
Mara Lúcia Martins Magela ◽  
Reginaldo de Camargo ◽  
Regina Maria Quintão Lana ◽  
Melissa Cristina de Carvalho Miranda ◽  
Raquel Pinheiro da Mota

In the current world scenario of agriculture it is necessary to find technologies to reach high productivity that are effective in providing soil conditioning improvement for the plants. Thus, this study analyzed the efficacy of organomineral fertilizers formulated with different organic matter sources on growth factors of maize. The experiment was done in a greenhouse at Campus Umuarama, Federal University of Uberlândia-MG, in a randomized block design, as a 2 x 5 + 2 factorial, containing two sources of organic matter, biosolid and filter cake, five doses of P2O5 recommendation for the crop and two additional treatments: mineral fertilization (100% of P2O5 of the recommended dose) and a control (no fertilizer), with four replications. Plant height, stalk diameter, and chlorophyll a and b were determined at 35 days after sowing (DAS); plant height, stalk diameter, shoot and root fresh and dry matter were determined at 65 DAS. The organomineral sources with biosolid and filter cake yielded greater height and diameter at 35 DAS than those of mineral fertilization. Regardless of the fertilizer organic matter source, stalk diameter at 35 DAS presented linear increase with increasing doses of the fertilizer sources. The use of fertilizer based on biosolid resulted in greater shoot fresh matter than the filter cake source, regardless of dose applied. In general, greater results were obtained for root fresh and dry matter at the greater fertilizer doses in comparison with the mineral fertilization. Organomineral fertilizers can be a viable alternative for partial or total substitution of mineral fertilization, since similar or better results were found for maize growth characteristics.


2016 ◽  
Vol 42 (1) ◽  
pp. 33-40 ◽  
Author(s):  
Anatoliy A. Khapugin ◽  
Tatyana B. Silaeva ◽  
Anastasia A. Semchuk ◽  
Elena N. Kunaeva

Abstract Population-based studies of endangered plant species are key methods for assessment of the status for these plants at any territory. Plant species of the Orchidaceae family are sensitive components in natural ecosystems. That is why determination of the status for their populations can be considered as indicators for the status of natural ecosystem position as a whole. Investigations of three Orchidaceae species populations (Orchis militaris L., Epipactis palustris (L.) Crantz, Malaxis monophyllos (L.) Swartz) were carried out in Central Russia (Republic of Mordovia). Abundance, density, structure and dynamics of populations of these species were studied. Species composition of accompanying flora was established for each rare species. Some morphometrical parameters of individuals for the studied species were measured. Features of ontogenetic spectrum for Orchis militaris and Epipactis palustris populations were shown.


Sign in / Sign up

Export Citation Format

Share Document