This study evaluated the performance of anaerobic co-digestion of cow manure (CM) and sheep manure (SM) in both batch and continuous digesters at 37 °C. Synergistic effects of co-digesting CM and SM at varying volatile solids (VS) ratios (1:0, 0:1, 3:1, 1:1, 1:3) were observed in the batch experiment, with the most effective degradation of cellulose (56%) and hemicellulose (55%), and thus, the highest cumulative methane yield (210 mL/gVSadded) obtained at a CM:SM ratio of 1:3. Co-digesting CM and SM improved the hydrolysis, as evidenced by the cellulase brought by SM and the increases of cellulolytic bacteria Clostridium. Besides, co-digestion enhanced the acidogenesis and methanogenesis, reflected by the enrichment of syntrophic bacteria Candidatus Cloacimonas and hydrogenotrophic archaea Methanoculleus (Coenzyme-B sulfoethylthiotransferase). When testing continuous digestion, the methane yield increased from 146 mL/gVS/d (CM alone) to 179 mL/gVS/d (CM:SM at 1:1) at a constant organic loading rate (OLR) of 1g VS/L/d and a hydraulic retention time (HRT) of 25 days. Furthermore, the anaerobic digestion process was enhanced when the daily feed changed back to CM alone, reflected by the improved daily methane yield (159 mL/VS/d). These results provided insights into the improvement of methane production during the anaerobic digestion of animal manure.
LINK
Camera trap technology has galvanized the study of predator-prey ecology in wild animal communities by expanding the scale and diversity of predator-prey interactions that can be analyzed. While observational data from systematic camera arrays have informed inferences on the spatiotemporal outcomes of predator-prey interactions, the capacity for observational studies to identify mechanistic drivers of species interactions is limited. Experimental study designs that utilize camera traps uniquely allow for testing hypothesized mechanisms that drive predator and prey behavior, incorporating environmental realism not possible in the lab while benefiting from the distinct capacity of camera traps to generate large data sets from multiple species with minimal observer interference. However, such pairings of camera traps with experimental methods remain underutilized. We review recent advances in the experimental application of camera traps to investigate fundamental mechanisms underlying predator-prey ecology and present a conceptual guide for designing experimental camera trap studies. Only 9% of camera trap studies on predator-prey ecology in our review mention experimental methods, but the application of experimental approaches is increasing. To illustrate the utility of camera trap-based experiments using a case study, we propose a study design that integrates observational and experimental techniques to test a perennial question in predator-prey ecology: how prey balance foraging and safety, as formalized by the risk allocation hypothesis. We discuss applications of camera trap-based experiments to evaluate the diversity of anthropogenic influences on wildlife communities globally. Finally, we review challenges to conducting experimental camera trap studies. Experimental camera trap studies have already begun to play an important role in understanding the predator-prey ecology of free-living animals, and such methods will become increasingly critical to quantifying drivers of community interactions in a rapidly changing world. We recommend increased application of experimental methods in the study of predator and prey responses to humans, synanthropic and invasive species, and other anthropogenic disturbances.
DOCUMENT
One of the most remarkable phenomena in nature is mimicry,in which one species (the mimic) evolves to imitate the phenotype ofanother species (the model). Several reasons for the origin of mimicryhave been proposed, but no definitive conclusion has been found yet. Inthis paper, we test several of these hypotheses through an agent based coevolutionarymodel. In particular, we consider two possible alternatives:(1) Deception, in which mimics evolve to imitate the phenotype of modelsthat predators avoid to eat, and (2) Coincidence, in which models evolvea warning color to avoid predation, which coincidentally benefits themimics. Our agent-based simulation shows that both these hypothesesare plausible origins for mimicry, but also that once a mimicry situationhas been established through coincidence, mimics will take advantage ofthe possibility for deception as well.
DOCUMENT
During times of high activity by predators and competitors, herbivores may be forced to forage in patches of low‐quality food. However, the relative importance in determining where and what herbivores forage still remains unclear, especially for small‐ and intermediate‐sized herbivores. Our objective was to test the relative importance of predator and competitor activity, and forage quality and quantity on the proportion of time spent in a vegetation type and the proportion of time spent foraging by the intermediate‐sized herbivore European hare (Lepus europaeus). We studied red fox (Vulpes vulpes) as a predator species and European rabbit (Oryctolagus cuniculus) as a competitor. We investigated the time spent at a location and foraging time of hare using GPS with accelerometers. Forage quality and quantity were analyzed based on hand‐plucked samples of a selection of the locally most important plant species in the diet of hare. Predator activity and competitor activity were investigated using a network of camera traps. Hares spent a higher proportion of time in vegetation types that contained a higher percentage of fibers (i.e., NDF). Besides, hares spent a higher proportion of time in vegetation types that contained relatively low food quantity and quality of forage (i.e., high percentage of fibers) during days that foxes (Vulpes vulpes) were more active. Also during days that rabbits (Oryctolagus cuniculus) were more active, hares spent a higher proportion of time foraging in vegetation types that contained a relatively low quality of forage. Although predation risk affected space use and foraging behavior, and competition affected foraging behavior, our study shows that food quality and quantity more strongly affected space use and foraging behavior than predation risk or competition. It seems that we need to reconsider the relative importance of the landscape of food in a world of fear and competition.
DOCUMENT
A bioaugmentation approach was used to enhance the performance of anaerobic digestion (AD) using cow manure (CM) as the substrate in a continuous system. To obtain the desirable microbial culture for bioaugmentation, a biochemical methane potential test (BMP) was used to evaluate three commonly used inocula namely (1) municipal solid waste (MSW), (2) wastewater treatment plant (WWTP), and (3) cow manure digester (CMMD) for their hydrolytic capacity. The highest lignocellulose removal (56% for cellulose and 50% for hemicellulose) and the most profusion of cellulolytic bacteria were obtained when CM was inoculated with CMMD. CMMD was thus used as the seed inoculum in a continuously operated reactor (Ra) with the fiber fraction of CM as the substrate to further enrich cellulolytic microbes. After 100 days (HRT: 30 days), the Bacteria fraction mainly contained Ruminofilibacter, norank_o_SBR1031, Treponema, Acetivibrio. Surprisingly, the Archaea fraction contained 97% ‘cellulolytic archaea’ norank_c_Bathyarchaeia (Phylum Bathyarchaeota). This enriched consortium was used in the bioaugmentation experiment. A positive effect of bioaugmentation was verified, with a substantial daily methane yield (DMY) enhancement (24.3%) obtained in the bioaugmented reactor (Rb) (179 mL CH4/gVS/d) than that of the control reactor (Rc) (144 mL CH4/gVS/d) (P < 0.05). Meanwhile, the effluent of Rb enjoyed an improved cellulose reduction (14.7%) than that of Rc, whereas the amount of hemicellulose remained similar in both reactors' effluent. When bioaugmentation stopped, its influence on the hydrolysis and methanogenesis sustained, reflected by an improved DMY (160 mL CH4/gVS/d) and lower cellulose content (53 mg/g TS) in Rb than those in Rc (DMY 144 mL/CH4/gVS/d and cellulose content 63 mg/g TS, respectively). The increased DMY of the continuous reactor seeded with a specifically enriched consortium able to degrade the fiber fraction in CM shows the feasibility of applying bioaugmentation in AD of CM.
LINK
Predation risk is a major driver of the distribution of prey animals, which typically show strong responses to cues for predator presence. An unresolved question is whether naïve individuals respond to mimicked cues, and whether such cues can be used to deter prey. We investigated whether playback of wolf sounds induces fear responses in naïve ungulates in a human-dominated landscape from which wolves have been eradicated since 1879. We conducted a playback experiment in mixed-coniferous and broadleaved forest that harboured three cervid and one suid species. At 36 locations, we played wolf sounds, sounds of local sheep or no sounds, consecutively, in random order, and recorded visit rate and group size, using camera traps. Visit rates of cervids and wild boar showed a clear initial reduction to playback of both wolf and sheep sounds, but the type of response differed between sound, forest type and species. For naïve wild boar in particular, responses to predator cues depended on forest type. Effects on visit rate disappeared within 21 days. Group sizes in all the species were not affected by the sound treatment. Our findings suggest that the responses of naïve ungulates to wolf sound seem to be species specific, depend on forest type and wear off in time, indicating habituation. Before we can successfully deter ungulates using predator sound, we should further investigate how different forest types affect the perception of naïve ungulates to these sounds, as responses to predator sound may depend on habitat characteristics.
MULTIFILE
Spatial variation in habitat riskiness has a major influence on the predator–prey space race. However, the outcome of this race can be modulated if prey shares enemies with fellow prey (i.e., another prey species). Sharing of natural enemies may result in apparent competition, and its implications for prey space use remain poorly studied. Our objective was to test how prey species spend time among habitats that differ in riskiness, and how shared predation modulates the space use by prey species. We studied a one‐predator, two‐prey system in a coastal dune landscape in the Netherlands with the European hare (Lepus europaeus) and European rabbit (Oryctolagus cuniculus) as sympatric prey species and red fox (Vulpes vulpes) as their main predator. The fine‐scale space use by each species was quantified using camera traps. We quantified residence time as an index of space use. Hares and rabbits spent time differently among habitats that differ in riskiness. Space use by predators and habitat riskiness affected space use by hares more strongly than space use by rabbits. Residence time of hare was shorter in habitats in which the predator was efficient in searching or capturing prey species. However, hares spent more time in edge habitat when foxes were present, even though foxes are considered ambush predators. Shared predation affected the predator–prey space race for hares positively, and more strongly than the predator–prey space race for rabbits, which were not affected. Shared predation reversed the predator–prey space race between foxes and hares, whereas shared predation possibly also released a negative association and promoted a positive association between our two sympatric prey species. Habitat riskiness, species presence, and prey species’ escape mode and foraging mode (i.e., central‐place vs. noncentral‐place forager) affected the prey space race under shared predation.
DOCUMENT
Hoe kunnen leeromgevingen in het beroepsonderwijs een rol vervullen bij het oplossen van complexe maatschappelijke problemen? Ilya Zitter, bijzonder lector Leeromgevingen in het Beroepsonderwijs bij Hogeschool Utrecht (HU), onderzoekt hoe je leeromgevingen zo kunt ontwerpen dat een innovatief, lerend systeem ontstaat, zonder sterke scheiding tussen onderwijs en praktijk. Op 25 maart gaf Zitter haar openbare les.
DOCUMENT
Het ministerie van Economische zaken, Landbouw en Innovatie (EL&I, thans EZ) heeft in 2012 het Lectoraat Welzijn van Dieren (Hogeschool VHL, Leeuwarden) gevraagd meer inzicht te verschaffen in de beweegredenen van mensen die kiezen voor een dier met een hoog welzijns- en gezondheidsrisico. Deze vraag werd gesteld vanuit het beleidsvoornemen deze groepen te bereiken met voorlichting aangaande de risico’s en alternatieven. De auteurs van het rapport doen meerdere aanbevelingen om particulieren te bereiken ter voorkoming van welzijnsproblemen bij hun huisdieren. Zij adviseren o.a. een cross-mediale aanpak waarin (aankomende) diereigenaren via verschillende kanalen en op verschillende manieren worden geïnformeerd over het houden van dieren. Ook bevelen de auteurs aan het gedrag van de diereigenaar bespreekbaar te maken in de discussie over het houden van ‘risicovolle’ dieren.
DOCUMENT
In human-controlled environments and in cultivated landscapes, the plants accommodate social, cultural and economic needs. This article will focus on the use of plants for agriculture, urban planning, forestry, environmental education and indoor decoration in The Netherlands. This exploration, based on literature review and observations, reveals mostly anthropocentric, instrumental and unsustainable practices. In urban landscapes, plants are pushed to the margins, if not entirely eradicated. This article shows that the moral recognition of plants is an ethical imperative, which is also critically important in order to achieve environmental sustainability. In line with ecocentric ethics and in the interest of long-term sustainability, this article suggests an alternative, more ethical and sustainable ways of relating to plants in The Netherlands and beyond. This is an Accepted Manuscript of an article published by Taylor & Francis in "Journal of Urbanism: International Research on Placemaking and Urban Sustainability" on 10/11/18 available online: https://doi.org/10.1080/17549175.2018.1527780 LinkedIn: https://www.linkedin.com/in/helenkopnina/
MULTIFILE
