Using crowd-sourced photos to assess seasonal patterns of visitor use in mountain-protected areas

Managing protected areas effectively requires information about patterns of visitor use, but these data are often limited. We explore how geotagged photos on Flickr, a popular photo-sharing social-media site, can generate hotspot maps and distribution models of temporal and spatial patterns of use in two mountain-protected areas of high conservation value. In Aconcagua Provincial Park (Argentina), two routes to the summit of Aconcagua were used in summer, but most visitors stayed close to the main road, using formal and informal walking trails and the Visitor Centre, while in winter, there was very limited visitation. In Kosciuszko National Park (Australia), alpine walking trails were popular in summer, but in winter, most visitors stayed in the lower altitude ski resorts and ski trails. Results demonstrate the usefulness of social-media data alone as well as a complement for visitor monitoring, providing spatial and temporal information for site-specific and park-level management of visitors and potential impacts in conservation areas.     

Between Scylla and Charybdis? On the place of economic methods in sustainability science

The flaws of mainstream economic methodology are becoming widely acknowledged. Should we, therefore, reject all of its concepts within the quest for sustainability? A predicament looms: neither would it make sense to neglect useful tools, nor to redundantly replicate the mainstream’s narrow perspective on sustainability problems. We argue that avoiding both fallacies is possible because power of judgment facilitates non-dogmatic methodological decisions: the scientists’ judgment, that is, the capacity to apply general concepts to specific situations, supports their decisions concerning which methods are suitable for tackling a given sustainability problem. The intersubjective quality of judgment prevents the resulting methodological pluralism from drifting toward arbitrariness.     

Analysis of the combustion and pyrolysis of dried sewage sludge by TGA and MS

In this study, the combustion and pyrolysis processes of three sewage sludge were investigated. The sewage sludge came from three wastewater treatment plants.Proximate and ultimate analyses were performed. The thermal behaviour of studied sewage sludge was investigated by thermogravimetric analysis with mass spectrometry (TGA-MS). The samples were heated from ambient temperature to 800 °C at a constant rate 10 °C/min in air (combustion process) and argon flows (pyrolysis process). The thermal profiles presented in form of TG/DTG curves were comparable for studied sludges. All TG/DTG curves were divided into three stages. The main decomposition of sewage sludge during the combustion process took place in the range 180–580 °C with c.a. 70% mass loss. The pyrolysis process occurred in lower temperature but with less mass loss. The evolved gaseous products (H₂, CH₄, CO₂, H₂O) from the decomposition of sewage sludge were identified on-line.     

Sex-specific conditional mating preferences in a cichlid fish: implications for sexual conflict

Conditional mating strategies enable individuals to modulate their mating behaviour depending on ‘individual status’ to maximise fitness. Theory predicts that variation in individual quality can lead to differences in mating preferences. However, empirical evidence is scarce particular in terms of variation in male and female strategies. Here, we experimentally investigated quality-dependent variation in mating preferences concerning reliable quality indicators in Pelvicachromis taeniatus, a colourful cichlid fish with mutual mate choice and ornamentation. Males as well as females were artificially manipulated in phenotypic quality by different feeding regimes. Ornamentation was connected to individual quality in both sexes. Males and females showed conditional mating strategies in different directions. Males showed prudent choice by preferring females of similar quality. In contrast to males, low-quality females preferred highly ornamented males, whereas high-quality females showed neither preferences for high- nor for low-quality males. The results suggest that individuals aim for specific benefits depending on individual quality. Furthermore, the conflicting conditional mating preferences of males and females might lead to sexual conflict, implicating a highly dynamical mating system that evolves even in absence of environmental changes.     

Spring phenological responses of marine and freshwater plankton to changing temperature and light conditions

Shifts in the timing and magnitude of the spring plankton bloom in response to climate change have been observed across a wide range of aquatic systems. We used meta-analysis to investigate phenological responses of marine and freshwater plankton communities in mesocosms subjected to experimental manipulations of temperature and light intensity. Systems differed with respect to the dominant mesozooplankton (copepods in seawater and daphnids in freshwater). Higher water temperatures advanced the bloom timing of most functional plankton groups in both marine and freshwater systems. In contrast to timing, responses of bloom magnitudes were more variable among taxa and systems and were influenced by light intensity and trophic interactions. Increased light levels increased the magnitude of the spring peaks of most phytoplankton taxa and of total phytoplankton biomass. Intensified size-selective grazing of copepods in warming scenarios affected phytoplankton size structure and lowered intermediate (20–200?μm)-sized phytoplankton in marine systems. In contrast, plankton peak magnitudes in freshwater systems were unaffected by temperature, but decreased at lower light intensities, suggesting that filter feeding daphnids are sensitive to changes in algal carrying capacity as mediated by light supply. Our analysis confirms the general shift toward earlier blooms at increased temperature in both marine and freshwater systems and supports predictions that effects of climate change on plankton production will vary among sites, depending on resource limitation and species composition.     

Mineralization of soil-aged isoproturon and isoproturon metabolites by Sphingomonas sp. strain SRS2

The aim of the study was to determine the effect of aging of the herbicide isoproturon and its metabolites monodesmethyl-isoproturon and 4-isopropyl-aniline in agricultural soil on their availability to the degrading bacterium Sphingomonas sp. strain SRS2. The 14C-ring-labeled isoproturon, monodesmethyl-isoproturon, and 4-isopropyl-aniline were added to sterilized soil and stored for 1, 49, 71, or 131 d before inoculation with strain SRS2. The availability of the compounds was estimated from the initial mineralization and the amount of 14CO2 recovered after 120 d of incubation. Aging in soil for 131 d reduced the initial mineralization of isoproturon and monodesmethyl-isoproturon and, in the case of isoproturon, also reduced the recovery of 14CO2. Initial mineralization and recovery of 14CO2 from aged 4-isopropyl-aniline were slightly reduced, but less 14CO2 was generally produced than with isoproturon or monodesmethyl-isoproturon. Thus, recovery of 14CO2 from 14C-isoproturon and 14C-monodesmethyl-isoproturon was 50.7 to 64.4% of the initially added 14C, while recovery from 14C-4-isopropyl-aniline was only 11.7 to 17.0%. Sorption measurements revealed similar Freundlich constants (K(f)) for isoproturon and monodesmethyl-isoproturon, whereas K(f) for 4-isopropyl-aniline was more than fivefold greater. The findings imply that in soil, partial degradation of isoproturon to 4-isopropyl-aniline may lead to reduced mineralization of the herbicide due to sorption of the aniline moiety.     

Managing fodder trees as a solution to human–livestock food conflicts and their contribution to income generation for smallholder farmers in southern Africa

Livestock production is an integral part of smallholder farming systems in southern Africa. While goats and sheep play some role in the smallholder farmer household economy, cattle are the predominant livestock species supplying draught power, milk, manure and meat. Production of cattle is based on range grazing. However, the nutritive value of the range is generally low depending on vegetation type and season. With the rapid increase in human population in southern Africa and the increasing need to produce staple food on a sustainable basis, smallholder farmers are increasingly encroaching onto lands formerly reserved for livestock grazing. Therefore, livestock subsisting on the range require supplementation. Conventional bought‐in supplements are expensive. Fodder trees and shrubs have been integrated within some farming systems of southern Africa as fodder banks with varying degrees of success. Work carried out in Tanzania, Malawi and Zimbabwe is reviewed to provide evidence on how the fodder tree technology has impacted on livestock production with special reference to smallholder dairy production, human food production and smallholder farmers’ income. For the wider adoption of the technology, a synopsis of the different scaling up pathways and approaches adopted by research and development agencies is presented.     

Adoption of renewable soil fertility replenishment technologies in the southern African region: Lessons learnt and the way forward

Low soil fertility is one of the most important biophysical constraints to increasing agricultural productivity in sub‐Saharan Africa. Several renewable soil fertility replenishment (RSFR) technologies that are based on nutrient re‐cycling principles have been developed in southern Africa. Some success stories have been recorded (e.g. nitrogen‐fixing legumes), but the adoption of RSFR technologies has generally lagged behind scientific advances thereby reducing the potential impacts of the technologies. This paper describes the major RSFR technologies being promoted in the region, synthesizes available information regarding their adoption by farmers, and identifies the challenges, key lessons learnt and the way forward for up‐scaling RSFR technologies in the region. The review indicated that farmer uptake of RSFR technologies depends on several factors that can be grouped into broad categories: technology‐specific (e.g. soil type, management regime), household‐specific (e.g. farmer perceptions, resource endowment, household size), policy and institutions context within which RSFR is disseminated (inputs and output prices, land tenure and property rights), and geo‐spatial (performance of species across different bio‐physical conditions, location of village). Adoption of RSFR technologies can be enhanced by targeting them to their biophysical and social niches, facilitating appropriate policy and institutional contexts for dissemination, understanding the broader context and dynamics of the adoption process, a paradigm shift in the approach to the dissemination of RSFR (e.g. expanding RSFR to high value crop systems, exploring synergy with inorganic fertilizer) and, targeted incentive systems that encourage farmers to take cognizance of natural resource implications when making agricultural production decisions.     

Optimisation of sampling for the temporal monitoring of technetium-99 in the Arctic marine environment

Monitoring of the marine environment for radioactivity, for both radiological protection and oceanographic purposes, remains an expensive and labour intensive activity due to the large sample volumes needed and the complex and lengthy analytical procedures required to measure low levels of contamination. Because of this, some consideration must be given to the design of sampling plans to ensure effective and efficient sampling that can be defended on the basis of scientific rationale. This article tests the hypothesis that geostatistical techniques may prove of use in the optimisation and design of sampling regimes for the monitoring of temporal fluctuations in the levels of technetium at a location in the Norwegian Arctic marine environment. The level of temporal correlation exhibited by two relevant time series was investigated and the information used to observe the effect of sampling frequency on the production of monthly estimates of activity of technetium in both seawater and seaweed. The results indicate that reduced sampling frequency allows production of estimates that acceptably replicate the actual data and that use of geostatistical procedures may offer advantages in the planning of monitoring systems for marine radioactivity. The use of an oceanographic model was also investigated as a means of assessing the temporal correlation prior to actual sampling, an approach that may offer significant advantages by reducing the need to have lengthy time series prior to designing sampling regimes.     

Antimicrobial activities of extracts from Indo-Pacific marine plants against marine pathogens and saprophytes

This study is the second of two surveys designed to systematically screen extracts from marine plants for antimicrobial effects against ecologically relevant marine microorganisms, and to compare results on a geographical basis. In the preceding survey, extracts from tropical Atlantic marine algae and seagrasses were screened in growth inhibition assays against the pathogenic fungus Lindra thalassiae, the saprophytic fungus Dendryphiella salina, the saprophytic stramenopiles, Halophytophthora spinosa and Schizochytrium aggregatum, and the pathogenic bacterium Pseudoaltermonas bacteriolytica. In this study, the same assay microorganisms were used to examine the antimicrobial effects of lipophilic and hydrophilic extracts from 54 species of marine algae and two species of seagrasses collected from Indo-Pacific reef habitats. Overall, 95% of all species surveyed in this study yielded extracts that were active against one or more, and 77% yielded extracts that were active against two or more assay microorganisms. Broad-spectrum activity against three or four assay microbes was observed in the extracts from 50 to 21% of all species, respectively. Extracts from the green alga Bryopsis pennata and the red alga Portieria hornemannii inhibited the growth of all assay microorganisms. Given that antimicrobial activity was prevalent among extracts of Indo-Pacific marine plants, it is interesting to note that the inhibitory effects of each extract varied considerably between the assay microorganisms. Overall, H. spinosa and D. salina were the most susceptible while L. thalassiae, S. aggregatum, and P. bacteriolytica were the most resistant to the extracts tested. These results provide good evidence that antimicrobial chemical defenses are widespread among Indo-Pacific marine plants. Further, the activity profiles of plant extracts suggest that antimicrobial secondary metabolites can have pathogen-selective or broad-spectrum effects. To confirm these results, chemical studies will be needed to isolate and characterize the compounds responsible for the observed antimicrobial activities.