Naturalness In Biological Conservation

Conservation scientists are arguing whether naturalness provides a reasonable imperative for conservation. To clarify this debate and the interpretation of the term natural, I analyze three management strategies – ecosystem preservation, ecosystem restoration, and ecosystem engineering – with respect to the naturalness of their outcomes. This analysis consists in two parts. First, the ambiguous term natural is defined in a variety of ways, including (1) naturalness as that which is part of nature, (2) naturalness as a contrast to artifactuality, (3) naturalness as an historical independence from human actions, and (4) naturalness as possession of certain properties. After that, I analyze the different conceptions with respect to their implications for the three management strategies. The main conclusion is that there exists no single conception of naturalness that could distinguish between the outcomes of the three management methods. Therefore, as long as the outcomes of the different methods are regarded as being of a different value in conservation, we should either abandon the idea of naturalness as the guiding concept in conservation or use the term natural only in the ways that take both its historical and feature dependent meanings into consideration.     

Global variability of food waste chemical composition and its consequences on the production of biofuels and chemical compounds

Journal of Material Cycles and Waste Management - The use of food waste (FW) for the production of biofuels and value-added compounds is growing worldwide. However, the significant chemical...     

Effects of low concentrations of the phenylurea herbicide diuron on biofilm algae and bacteria

A system of recirculating channels was used in this study to examine the long-term effects (29 d) of environmentally realistic concentrations of the herbicide diuron (from 0.07 to 7 μg L⁻¹) on biofilm communities. The autotrophic activity of biofilms was affected by this herbicide, as reflected by a marked decrease in the photosynthetic efficiency. Diuron exposure also increased chlorophyll-a content and reduced the biovolume of diatom taxa at low concentrations. The effects on bacteria were also remarkable. Bacterial abundance was reduced after a week of exposure to the herbicide at a range of concentrations. Effects were on the number of live bacteria and on the increase in the leucine-aminopeptidase activity. It is suggested that inputs of herbicides to the river ecosystem at low concentrations may cause a chain of effects in the biofilm, which include inhibitory effects on algae but also indirect effects on the relationships between biofilm components.     

The effect of visitors’ pressure on the spatial variability of sandy soil in an urban parks in Tel Aviv

The effect of visitors' pressure on the spatial variability of soil properties was investigated in three open green areas in Tel Aviv. Six types of micro-environments were chosen: under oak and pine tree canopy with low (OL and PL) and high (OH and PH) visitors' pressure; herbaceous area without visitors' pressure (HE); and resting area under high visitors' pressure (RA). For each micro-environment soil samples were collected from the upper 0-5 cm depth for organic matter content and moisture determination. Before sampling, soil surface compaction and litter biomass were measured. Soil properties were affected by visitors' pressure and by the type of micro-environment. Soil organic matter content and soil moisture proved significantly higher under oak trees at low visitors' pressure. Average litter biomass significantly decreased with increasing visitors' pressure in the tree micro-environments. Average penetration depth decreased significantly with increased visitors' pressure in all micro-environments. In all the cases where averages significantly decreased, variance significantly decreased too, but the coefficient of variations increased. This means that variances changed slower than averages. Changes in averages were accompanied by a change of data population structure, which indicated more soil spatial homogeneity under high visitors' pressure. The data from different intervals of data population of soil properties demonstrated the different sensitivity to visitors' pressure.     

SALSA: a simulation tool to assess ecological sustainability of agricultural production

In order to assess the ecological sustainability of agricultural production systems, there is a need for effective tools. We describe an environmental systems analysis tool called SALSA (Systems Ana/ysis for Sustainable Agriculture). It consists of substance/material flow models in which the simulation results are interpreted with life-cycle assessment methodology. The application of SALSA is demonstrated in a case study in which three different ways of producing pigs are compared with respect to energy input and the environmental impacts of global warming, eutrophication, and acidification. The scenario that combined a low-protein diet without soy meal with an improved manure-management technique with low nitrogen losses was the best for all impact categories studied. The strength of the SALSA models was their capacity to capture consequences of management options that had an influence on several processes on a farm, which enabled the type of complex studies we describe.     

Influence of americium-241 on the microbial population and biodegradation of organic waste

The present study investigated the influence of ²⁴¹Am on microbial growth and the degradation of organic waste. Leachate samples collected in a lysimeter were periodically analyzed for bacterial growth, under both aerobic and anaerobic conditions. ²⁴¹Am inhibited bacterial growth, and the degradation of organic matter was delayed in comparison with the control. Minimal inhibitory concentration assays and survival curves revealed that it inhibits the growth of Pseudomonas putida F1. The assay also revealed that ²⁴¹Am is more toxic than ²³⁸U, Zn²⁺ and Cd²⁺. This study further led to the finding of four new radionuclide-tolerant bacterial strains: Flavobacterium spp., Pseudomonas gladioli, Chryseobacterium indologenes and Ochrobactrum anthropi. The survival curves of P. gladioli, C. indologenes revealed that these bacteria are resistant to metal as consortia.     

Adapting to Climate Variability and Change: Experiences from Cereal-Based Farming in the Central Rift and Kobo Valleys, Ethiopia

Small-holder farmers in Ethiopia are facing several climate related hazards, in particular highly variable rainfall with severe droughts which can have devastating effects on their livelihoods. Projected changes in climate are expected to aggravate the existing challenges. This study examines farmer perceptions on current climate variability and long-term changes, current adaptive strategies, and potential barriers for successful further adaptation in two case study regions—the Central Rift Valley (CRV) and Kobo Valley. The study was based on a household questionnaire, interviews with key stakeholders, and focus group discussions. The result revealed that about 99 % of the respondents at the CRV and 96 % at the Kobo Valley perceived an increase in temperature and 94 % at CRV and 91 % at the Kobo Valley perceived a decrease in rainfall over the last 20–30 years. Inter-annual and intraseasonal rainfall variability also has increased according to the farmers. The observed climate data (1977–2009) also showed an increasing trend in temperature and high inter-annual and intra-seasonal rainfall variability. In contrast to farmers’ perceptions of a decrease in rainfall totals, observed rainfall data showed no statistically significant decline. The interaction among various bio-physical and socio-economic factors, changes in rainfall intensity and reduced water available to crops due to increased hot spells, may have influenced the perception of farmers with respect to rainfall trends. In recent decades, farmers in both the CRV and Kobo have changed farming practices to adapt to perceived climate change and variability, for example, through crop and variety choice, adjustment of cropping calendar, and in situ moisture conservation. These relatively low-cost changes in farm practices were within the limited adaptation capacity of farmers, which may be insufficient to deal with the impacts of future climate change. Anticipated climate change is expected to impose new risks outside the range of current experiences. To enable farmers to adapt to these impacts critical technological, institutional, and market-access constraints need to be removed. Inconsistencies between farmers’ perceptions and observed climate trends (e.g., decrease in annual rainfall) could lead to sub-optimal or counterproductive adaptations, and therefore must be removed by better communication and capacity building, for example through Climate Field Schools. Enabling strategies, which are among others targeted at agricultural inputs, credit supply, market access, and strengthening of local knowledge and information services need to become integral part of government policies to assist farmers to adapt to the impacts of current and future climate change.