Choosing best practices for managing impacts of trawl fishing on seabed habitats and biota
Mcconnaughey, Robert A. ; Hiddink, Jan G. ; Jennings, Simon ; Pitcher, Roland ; Kaiser, Michel J. ; Suuronen, Petri ; Sciberras, Marija ; Rijnsdorp, Adriaan D. ; Collie, Jeremy S. ; Mazor, Tessa ; Amoroso, Ricardo O. ; Parma, Ana M. ; Hilborn, Ray - \ 2020
Fish and Fisheries 21 (2020)2. - ISSN 1467-2960 - p. 319 - 337.
benthos - dredging - ecosystem-based fishery management - impact-yield model - trade-offs - trawling
Bottom trawling accounts for almost one quarter of global fish landings but may also have significant and unwanted impacts on seabed habitats and biota. Management measures and voluntary industry actions can reduce these impacts, helping to meet sustainability objectives for fisheries, conservation and environmental management. These include changes in gear design and operation of trawls, spatial controls, impact quotas and effort controls. We review nine different measures and actions and use published studies and
a simple conceptual model to evaluate and compare their performance. The risks and benefits of these management measures depend on the extent to which the fishery is already achieving management objectives for target stocks and the characteristics of the management system that is already in place. We offer guidance on identifying best practices for trawl-fisheries management and show that best practices and their likelihood of reducing trawling impacts depend on local, national and regional management objectives and priorities, societal values and resources for implementation. There is no universal
best practice, and multiple management measures and industry actions are required to meet sustainability objectives and improve trade-offs between food production and environmental protection.
Benefits and trade-offs of replacing synthetic fertilizers by animal manures in crop production in China: A meta-analysis
Zhang, Xiaoying ; Fang, Qunchao ; Zhang, Tao ; Ma, Wenqi ; Velthof, Gerard L. ; Hou, Yong ; Oenema, Oene ; Zhang, Fusuo - \ 2020
Global Change Biology 26 (2020)2. - ISSN 1354-1013 - p. 888 - 900.
ammonia emissions - crop yield - fertilizers - greenhouse gases - livestock manure - meta-analysis - soil type - trade-offs
Recycling of livestock manure to agricultural land may reduce the use of synthetic fertilizer and thereby enhance the sustainability of food production. However, the effects of substitution of fertilizer by manure on crop yield, nitrogen use efficiency (NUE), and emissions of ammonia (NH3), nitrous oxide (N2O) and methane (CH4) as function of soil and manure properties, experimental duration and application strategies have not been quantified systematically and convincingly yet. Here, we present a meta-analysis of these effects using results of 143 published studies in China. Results indicate that the partial substitution of synthetic fertilizers by manure significantly increased the yield by 6.6% and 3.3% for upland crop and paddy rice, respectively, but full substitution significantly decreased yields (by 9.6% and 4.1%). The response of crop yields to manure substitution varied with soil pH and experimental durations, with relatively large positive responses in acidic soils and long-term experiments. NUE increased significantly at a moderate ratio (<40%) of substitution. NH3 emissions were significantly lower with full substitution (62%–77%), but not with partial substitution. Emissions of CH4 from paddy rice significantly increased with substitution ratio (SR), and varied by application rates and manure types, but N2O emissions decreased. The SR did not significantly influence N2O emissions from upland soils, and a relative scarcity of data on certain manure characteristic was found to hamper identification of the mechanisms. We derived overall mean N2O emission factors (EF) of 0.56% and 0.17%, as well as NH3 EFs of 11.1% and 6.5% for the manure N applied to upland and paddy soils, respectively. Our study shows that partial substitution of fertilizer by manure can increase crop yields, and decrease emissions of NH3 and N2O, but depending on site-specific conditions. Manure addition to paddy rice soils is recommended only if abatement strategies for CH4 emissions are also implemented.
Data from: No gains for bigger brains: functional and neuroanatomical consequences of relative brain size in a parasitic wasp
Woude, E. van der; Groothuis, J. ; Smid, H.M. - \ 2019
artificial selection - trade-offs - constraints - insects - host-parasite interaction - bidirectional artificial selection - brain-size - appetitive olfactory conditioning - brain scaling - parasitic wasp - parasitoid - longevity - Nasonia vitripennis
Heritable genetic variation in relative brain size can underlie the relationship between brain performance and the relative size of the brain. We used bidirectional artificial selection to study the consequences of genetic variation in relative brain size on brain morphology, cognition and longevity in Nasonia vitripennis parasitoid wasps. Our results show a robust change in relative brain size after 26 generations of selection and 6 generations of relaxation. Total average neuropil volume of the brain was 16% larger in wasps selected for relatively large brains than in wasps selected for relatively small brains, whereas the body length of the large-brained wasps was smaller. Furthermore, the relative volume of the antennal lobes was larger in wasps with relatively large brains. Relative brain size did not influence olfactory memory retention, whereas wasps that were selected for larger relative brain size had a shorter longevity, which was even further reduced after a learning experience. These effects of genetic variation on neuropil composition and memory retention are different from previously described effects of phenotypic plasticity in absolute brain size. In conclusion, having relatively large brains may be costly for N. vitripennis, whereas no cognitive benefits were recorded.
Pervasive gene expression responses to a fluctuating diet in Drosophila melanogaster : The importance of measuring multiple traits to decouple potential mediators of life span and reproduction
Zandveld, Jelle ; Heuvel, Joost van den; Mulder, Maarten ; Brakefield, Paul M. ; Kirkwood, Thomas B.L. ; Shanley, Daryl P. ; Zwaan, Bas J. - \ 2017
Evolution 71 (2017)11. - ISSN 0014-3820 - p. 2572 - 2583.
Fecundity - gene regulatory networks - life span regulation - phenotypic plasticity - trade-offs
Phenotypic plasticity is an important concept in life-history evolution, and most organisms, including Drosophila melanogaster, show a plastic life-history response to diet. However, little is known about how these life-history responses are mediated. In this study, we compared adult female flies fed an alternating diet (yoyo flies) with flies fed a constant low (CL) or high (CH) diet and tested how whole genome expression was affected by these diet regimes and how the transcriptional responses related to different life-history traits. We showed that flies were able to respond quickly to diet fluctuations throughout life span by drastically changing their transcription. Importantly, by measuring the response of multiple life-history traits we were able to decouple groups of genes associated with life span or reproduction, life-history traits that often covary with a diet change. A coexpression network analysis uncovered which genes underpin the separate and shared regulation of these life-history traits. Our study provides essential insights to help unravel the genetic architecture mediating life-history responses to diet, and it shows that the flies’ whole genome transcription response is highly plastic.
Negative Epistasis and Evolvability in TEM-1 ß-Lactamase- The Thin Line between an Enzyme's Conformational Freedom and Disorder
Dellus-Gur, E. ; Elias, M. ; Caselli, E. ; Prati, F. ; Salverda, M.L.M. ; Visser, J.A.G.M. de; Fraser, J.S. ; Tawfik, D.S. - \ 2015
Journal of Molecular Biology 427 (2015)14. - ISSN 0022-2836 - p. 2396 - 2409.
empirical fitness landscapes - antibiotic-resistance - protein structures - escherichia-coli - substrate-specificity - sequence space - sign epistasis - omega-loop - trade-offs - evolution
Epistasis is a key factor in evolution since it determines which combinations of mutations provide adaptive solutions and which mutational pathways toward these solutions are accessible by natural selection. There is growing evidence for the pervasiveness of sign epistasis—a complete reversion of mutational effects, particularly in protein evolution—yet its molecular basis remains poorly understood. We describe the structural basis of sign epistasis between G238S and R164S, two adaptive mutations in TEM-1 ß-lactamase— an enzyme that endows antibiotics resistance. Separated by 10 Å, these mutations initiate two separate trajectories toward increased hydrolysis rates and resistance toward second and third-generation cephalosporins antibiotics. Both mutations allow the enzyme's active site to adopt alternative conformations and accommodate the new antibiotics. By solving the corresponding set of crystal structures, we found that R164S causes local disorder whereas G238S induces discrete conformations. When combined, the mutations in 238 and 164 induce local disorder whereby nonproductive conformations that perturb the enzyme's catalytic preorganization dominate. Specifically, Asn170 that coordinates the deacylating water molecule is misaligned, in both the free form and the inhibitor-bound double mutant. This local disorder is not restored by stabilizing global suppressor mutations and thus leads to an evolutionary cul-de-sac. Conformational dynamism therefore underlines the reshaping potential of protein's structures and functions but also limits protein evolvability because of the fragility of the interactions networks that maintain protein structures
The effects of drought and shade on the performance, morphology and physiology of Ghanaian tree species
Amissah, L. ; Mohren, G.M.J. ; Kyereh, B. ; Poorter, L. - \ 2015
PLoS ONE 10 (2015)4. - ISSN 1932-6203
tropical forest - water relations - rain-forest - seedling establishment - desiccation-tolerance - carbon gain - trade-offs - photosynthetic acclimation - niche differentiation - relative importance
In tropical forests light and water availability are the most important factors for seedling growth and survival but an increasing frequency of drought may affect tree regeneration. One central question is whether drought and shade have interactive effects on seedling growth and survival. Here, we present results of a greenhouse experiment, in which seedlings of 10 Ghanaian tree species were exposed to combinations of strong seasonal drought (continuous watering versus withholding water for nine weeks) and shade (5% irradiance versus 20% irradiance). We evaluated the effects of drought and shade on seedling survival and growth and plasticity of 11 underlying traits related to biomass allocation, morphology and physiology. Seedling survival under dry conditions was higher in shade than in high light, thus providing support for the “facilitation hypothesis” that shade enhances plant performance through improved microclimatic conditions, and rejecting the trade-off hypothesis that drought should have stronger impact in shade because of reduced root investment. Shaded plants had low biomass fraction in roots, in line with the trade-off hypothesis, but they compensated for this with a higher specific root length (i.e., root length per unit root mass), resulting in a similar root length per plant mass and, hence, similar water uptake capacity as high-light plants. The majority (60%) of traits studied responded independently to drought and shade, indicating that within species shade- and drought tolerances are not in trade-off, but largely uncoupled. When individual species responses were analysed, then for most of the traits only one to three species showed significant interactive effects between drought and shade. The uncoupled response of most species to drought and shade should provide ample opportunity for niche differentiation and species coexistence under a range of water and light conditions. Overall our greenhouse results suggest that, in the absence of root competition shaded tropical forest tree seedlings may be able to survive prolonged drought.
Environmental proxies of antigen exposure explain variation in immune investment better than indices of pace of life
Horrocks, N.P.C. ; Hegemann, A. ; Ostrowski, S. ; Ndithia, H. ; Shobrak, M. ; Williams, J.B. ; Matson, K.D. ; Tieleman, B.I. - \ 2015
Oecologia 177 (2015)1. - ISSN 0029-8549 - p. 281 - 290.
female pied flycatchers - tropical birds - trade-offs - ecological immunology - microbial diversity - natural antibodies - aridity gradient - south-africa - history - patterns
Investment in immune defences is predicted to covary with a variety of ecologically and evolutionarily relevant axes, with pace of life and environmental antigen exposure being two examples. These axes may themselves covary directly or inversely, and such relationships can lead to conflicting predictions regarding immune investment. If pace of life shapes immune investment then, following life history theory, slow-living, arid zone and tropical species should invest more in immunity than fast-living temperate species. Alternatively, if antigen exposure drives immune investment, then species in antigen-rich tropical and temperate environments are predicted to exhibit higher immune indices than species from antigen-poor arid locations. To test these contrasting predictions we investigated how variation in pace of life and antigen exposure influence immune investment in related lark species (Alaudidae) with differing life histories and predicted risks of exposure to environmental microbes and parasites. We used clutch size and total number of eggs laid per year as indicators of pace of life, and aridity, and the climatic variables that influence aridity, as correlates of antigen abundance. We quantified immune investment by measuring four indices of innate immunity. Pace of life explained little of the variation in immune investment, and only one immune measure correlated significantly with pace of life, but not in the predicted direction. Conversely, aridity, our proxy for environmental antigen exposure, was predictive of immune investment, and larks in more mesic environments had higher immune indices than those living in arid, low-risk locations. Our study suggests that abiotic environmental variables with strong ties to environmental antigen exposure can be important correlates of immunological variation.
Competing discourses on REDD+: Global debates versus the first Indian REDD+ project
Vijge, M.J. - \ 2015
Forest Policy and Economics 56 (2015). - ISSN 1389-9341 - p. 38 - 47.
ecosystem services - forest governance - costa-rica - social safeguards - carbon offsets - climate-change - co-benefits - trade-offs - deforestation - interests
This article analyzes three of themost contentious scholarly and political debates regarding REDD+, focusing on 1) what REDD+ should achieve; 2) who should monitor REDD+ outcomes; and 3) how REDD+ should be financed. In analyzing these, the article conceptualizes three sets of storylines and assesseswhich of the identified storylines resonate in the first Indian REDD+ project, focusing on both stakeholders' views and project design. The three identified questions do not give rise to contentious debates among stakeholders of the REDD+project. Contrasting views on REDD+found in scholarly and political debates – such as carbon versus non-carbon objectives, authority of technical experts versus local communities, and market versus fund-based approaches – are not prevalent among project stakeholders, who believe that different approaches to REDD+ can be combined and can even reinforce each other. Project stakeholders prefer non-carbon benefits as the project's main objective to be monitored jointly by experts and local communities, and favor a mix of fund- and market-based approaches. This is also reflected in the project design. The conclusion reflects on the insights that the multi-level discourse analysis in this article generated, including for REDD+ in general.
Model collaboration for the improved assessment of biomass supply, demand, and impacts
Wicke, B. ; Hilst, F. van der; Daioglou, V. ; Banse, M. ; Beringer, T. ; Gerssen-Gondelach, S. ; Heijnen, S. ; Karssenberg, D. ; Laborde, D. ; Lippe, M. ; Meijl, H. van; Nassar, A. ; Powell, J.P. ; Prins, A.G. ; Rose, S.N.K. ; Smeets, E.M.W. ; Stehfest, E. ; Tyner, W.E. ; Verstegen, J.A. ; Valin, H. ; Vuuren, D.P. van; Yeh, S. ; Faaij, A.P.C. - \ 2015
Global change biology Bioenergy 7 (2015)3. - ISSN 1757-1693 - p. 422 - 437.
land-use change - global agricultural markets - greenhouse-gas emissions - eu biofuel policies - bioenergy production - united-states - energy crops - trade-offs - bio-energy - ethanol
Existing assessments of biomass supply and demand and their impacts face various types of limitations and uncertainties, partly due to the type of tools and methods applied (e.g., partial representation of sectors, lack of geographical details, and aggregated representation of technologies involved). Improved collaboration between existing modeling approaches may provide new, more comprehensive insights, especially into issues that involve multiple economic sectors, different temporal and spatial scales, or various impact categories. Model collaboration consists of aligning and harmonizing input data and scenarios, model comparison and/or model linkage. Improved collaboration between existing modeling approaches can help assess (i) the causes of differences and similarities in model output, which is important for interpreting the results for policy-making and (ii) the linkages, feedbacks, and trade-offs between different systems and impacts (e.g., economic and natural), which is key to a more comprehensive understanding of the impacts of biomass supply and demand. But, full consistency or integration in assumptions, structure, solution algorithms, dynamics and feedbacks can be difficult to achieve. And, if it is done, it frequently implies a trade-off in terms of resolution (spatial, temporal, and structural) and/or computation. Three key research areas are selected to illustrate how model collaboration can provide additional ways for tackling some of the shortcomings and uncertainties in the assessment of biomass supply and demand and their impacts. These research areas are livestock production, agricultural residues, and greenhouse gas emissions from land-use change. Describing how model collaboration might look like in these examples, we show how improved model collaboration can strengthen our ability to project biomass supply, demand, and impacts. This in turn can aid in improving the information for policy-makers and in taking better-informed decisions.
A novel integrative method for measuring body condition in ecological studies based on physiological dysregulation
Milot, E. ; Cohen, A.A. ; Vézina, F. ; Buehler, D.M. ; Matson, K.D. ; Piersma, T. - \ 2014
Methods in Ecology and Evolution 5 (2014)2. - ISSN 2041-210X - p. 146 - 155.
mahalanobis distance - sexual selection - annual-cycle - trade-offs - shorebirds - birds - antioxidants - acclimation - adjustments - performance
1.The body condition of free-ranging animals affects their response to stress, decisions, ability to fulfil vital needs and, ultimately, fitness. However, this key attribute in ecology remains difficult to assess, and there is a clear need for more integrative measures than the common univariate proxies. 2.We propose a systems biology approach that positions individuals along a gradient from a ‘normal/optimal’ to ‘abnormal/suboptimal’ physiological state based on Mahalanobis distance computed from physiological biomarkers. We previously demonstrated the validity of this approach for studying ageing in humans; here, we illustrate its broad potential for ecological studies. 3.As an example, we used biomarker data on shorebirds and found that birds with an abnormal condition had a lower maximal thermogenic capacity and higher scores of inflammation, with important implications for their ecology and health. Moreover, Mahalanobis distance captured a signal of condition not detected by the individual biomarkers. 4.Overall, our results on birds and humans show that individuals with abnormal physiologies are indeed in worse condition. Moreover, our approach appears not to be particularly sensitive to which set of biomarkers is used to assess condition. Consequently, it could be applied easily to existing ecological data sets. 5.Our approach provides a general, powerful way to measure condition that helps resolve confusion as to how to deal with complex interactions and interdependence among multiple physiological and condition measures. It can be applied directly to topics such as the effect of environmental quality on body condition, risks of health outcomes, mechanisms of adaptive phenotypic plasticity, and mechanisms behind long-term processes such as senescence.
Pattern formation at multiple spatial scales drives the resilience of mussel bed ecosystems
Liu, Q. ; Herman, P.M.J. ; Mooij, W.M. ; Huisman, J. ; Scheffer, M. ; Olff, H. ; Koppel, J. van de - \ 2014
Nature Communications 5 (2014). - ISSN 2041-1723
self-organization - trade-offs - dynamics - systems - model
Self-organized complexity at multiple spatial scales is a distinctive characteristic of biological systems. Yet, little is known about how different self-organizing processes operating at different spatial scales interact to determine ecosystem functioning. Here we show that the interplay between self-organizing processes at individual and ecosystem level is a key determinant of the functioning and resilience of mussel beds. In mussel beds, self-organization generates spatial patterns at two characteristic spatial scales: small-scale net-shaped patterns due to behavioural aggregation of individuals, and large-scale banded patterns due to the interplay of between-mussel facilitation and resource depletion. Model analysis reveals that the interaction between these behavioural and ecosystem-level mechanisms increases mussel bed resilience, enables persistence under deteriorating conditions and makes them less prone to catastrophic collapse. Our analysis highlights that interactions between different forms of self-organization at multiple spatial scales may enhance the intrinsic ability of ecosystems to withstand both natural and human-induced disturbances.
Mortality-minimizing sandpipers vary stopover behavior dependent on age and geographic proximity to migrating predators
Hope, D.D. ; Lank, D.B. ; Ydenberg, R.C. - \ 2014
Behavioral Ecology and Sociobiology 68 (2014)5. - ISSN 0340-5443 - p. 827 - 838.
calidris-mauri - western sandpipers - site selection - trade-offs - group-size - sex-ratio - danger - vigilance - birds - risk
Ecological theory for long-distance avian migration considers time-, energy-, and mortality-minimizing tactics, but predictions about the latter have proven elusive. Migrants must make behavioral decisions that can favor either migratory speed or safety from predators, but often not both. We compare the behavior of adult and juvenile western sandpipers Calidris mauri during the course of their temporally segregated passages at a major stopover site. Here, the passage and winter arrival of an important predator, the peregrine falcon Falco peregrinus begins near the end of the adult sandpiper passage (July) and increases rapidly through the juvenile passage (August). The mortality-minimizing hypothesis predicts that as the falcon front is distant but approaching, sandpipers should initially increase the fuel-loading rate (lowered vigilance and predator apprehension) to increase migration speed and so maintain their head start. As the falcon front gains proximity to and passes over the stopover site, sandpipers should become increasingly cautious. Our measurements show that adults decreased vigilance during the period prior to falcon arrival, and had lower vigilance overall than juveniles. Juveniles were more apprehensive, flying further and longer in response to disturbance by a falcon silhouette. This trend was reversed in response to a human approach. Both groups were more vigilant and more apprehensive in a study year with earlier falcon arrival. These results suggest that late (juvenile) and early (adult) migrants minimize mortality on migration in different ways, adults by increased migratory speed at the expense of caution on stopover sites, and juveniles by increased caution at the expense of speed.
Synergistic effects of direct and indirect defences on herbivore egg survival in a wild crucifer
Fatouros, N.E. ; Pineda, A. ; Huigens, M.E. ; Broekgaarden, C. ; Shimwela, M.M. ; Figueroa Candia, I.A. ; Verbaarschot, P. ; Bukovinszky, T. - \ 2014
Proceedings of the Royal Society. B: Biological Sciences 281 (2014)1789. - ISSN 0962-8452 - 9 p.
furcifera horvath homoptera - plant defense - trade-offs - antiherbivore defenses - natural enemies - fitness costs - brassica-rapa - resistance - oviposition - butterflies
Evolutionary theory of plant defences against herbivores predicts a trade-off between direct (anti-herbivore traits) and indirect defences (attraction of carnivores) when carnivore fitness is reduced. Such a trade-off is expected in plant species that kill herbivore eggs by exhibiting a hypersensitive response (HR)-like necrosis, which should then negatively affect carnivores. We used the black mustard (Brassica nigra) to investigate how this potentially lethal direct trait affects preferences and/or performances of specialist cabbage white butterflies (Pieris spp.), and their natural enemies, tiny egg parasitoid wasps (Trichogramma spp.). Both within and between black mustard populations, we observed variation in the expression of Pieris egg-induced HR. Butterfly eggs on plants with HR-like necrosis suffered lower hatching rates and higher parasitism than eggs that did not induce the trait. In addition, Trichogramma wasps were attracted to volatiles of egg-induced plants that also expressed HR, and this attraction depended on the Trichogramma strain used. Consequently, HR did not have a negative effect on egg parasitoid survival. We conclude that even within a system where plants deploy lethal direct defences, such defences may still act with indirect defences in a synergistic manner to reduce herbivore pressure.
Ecosystem Services and Opportunity Costs Shift Spatial Priorities for Conserving Forest Biodiversity
Schroter, M. ; Rusch, G.M. ; Barton, D.N. ; Blumentrath, S. ; Nordén, B. - \ 2014
PLoS ONE 9 (2014)11. - ISSN 1932-6203 - 12 p.
protected areas - trade-offs - rich forests - conservation - landscapes - strategies - payments - benefits - science - norway
Inclusion of spatially explicit information on ecosystem services in conservation planning is a fairly new practice. This study analyses how the incorporation of ecosystem services as conservation features can affect conservation of forest biodiversity and how different opportunity cost constraints can change spatial priorities for conservation. We created spatially explicit cost-effective conservation scenarios for 59 forest biodiversity features and five ecosystem services in the county of Telemark (Norway) with the help of the heuristic optimisation planning software, Marxan with Zones. We combined a mix of conservation instruments where forestry is either completely (non-use zone) or partially restricted (partial use zone). Opportunity costs were measured in terms of foregone timber harvest, an important provisioning service in Telemark. Including a number of ecosystem services shifted priority conservation sites compared to a case where only biodiversity was considered, and increased the area of both the partial (+36.2%) and the non-use zone (+3.2%). Furthermore, opportunity costs increased (+6.6%), which suggests that ecosystem services may not be a side-benefit of biodiversity conservation in this area. Opportunity cost levels were systematically changed to analyse their effect on spatial conservation priorities. Conservation of biodiversity and ecosystem services trades off against timber harvest. Currently designated nature reserves and landscape protection areas achieve a very low proportion (9.1%) of the conservation targets we set in our scenario, which illustrates the high importance given to timber production at present. A trade-off curve indicated that large marginal increases in conservation target achievement are possible when the budget for conservation is increased. Forty percent of the maximum hypothetical opportunity costs would yield an average conservation target achievement of 79%.
Climate change mitigation and adaptation in the land use sector: from complementarity to synergy
Duguma, L.A. ; Minang, P.A. ; Noordwijk, M. van - \ 2014
Environmental Management 54 (2014)3. - ISSN 0364-152X - p. 420 - 432.
integrating mitigation - multibusiness firms - ecosystem services - change policy - trade-offs - agriculture - performance - carbon
Currently, mitigation and adaptation measures are handled separately, due to differences in priorities for the measures and segregated planning and implementation policies at international and national levels. There is a growing argument that synergistic approaches to adaptation and mitigation could bring substantial benefits at multiple scales in the land use sector. Nonetheless, efforts to implement synergies between adaptation and mitigation measures are rare due to the weak conceptual framing of the approach and constraining policy issues. In this paper, we explore the attributes of synergy and the necessary enabling conditions and discuss, as an example, experience with the Ngitili system in Tanzania that serves both adaptation and mitigation functions. An in-depth look into the current practices suggests that more emphasis is laid on complementarity—i.e., mitigation projects providing adaptation co-benefits and vice versa rather than on synergy. Unlike complementarity, synergy should emphasize functionally sustainable landscape systems in which adaptation and mitigation are optimized as part of multiple functions. We argue that the current practice of seeking co-benefits (complementarity) is a necessary but insufficient step toward addressing synergy. Moving forward from complementarity will require a paradigm shift from current compartmentalization between mitigation and adaptation to systems thinking at landscape scale. However, enabling policy, institutional, and investment conditions need to be developed at global, national, and local levels to achieve synergistic goals.
Development of a generalist predator, Podisus maculiventris, on glucosinolate sequestering and nonsequestering prey
Geem, M. van; Harvey, J.A. ; Gols, R. - \ 2014
Naturwissenschaften 101 (2014)9. - ISSN 0028-1042 - p. 707 - 714.
sawfly athalia-rosae - plant-chemical defense - pyrrolizidine alkaloids - insect herbivore - multitrophic interactions - specialist herbivore - trophic levels - trade-offs - sequestration - host
Insect herbivores exhibit various strategies to counter the toxic effects of plant chemical defenses. These strategies include the detoxification, excretion, and sequestration of plant secondary metabolites. The latter strategy is often considered to provide an additional benefit in that it provides herbivores with protection against natural enemies such as predators. Profiles of sequestered chemicals are influenced by the food plants from which these chemicals are derived. We compared the effects of sequestration and nonsequestration of plant secondary metabolites in two specialist herbivores on the development of a generalist predator, Podisus maculiventris. Profiles of glucosinolates, secondary metabolites characteristic for the Brassicaceae, are known to differ considerably both inter- and intraspecifically. Throughout their immature (=nymphal) development, the predator was fed on larval stages of either sequestering (turnip sawfly, Athalia rosae) or nonsequestering (small cabbage white butterfly, Pieris rapae) prey that in turn had been feeding on plants originating from three wild cabbage (Brassica oleracea) populations that have previously been shown to differ in their glucosinolate profiles. We compared survival, development time, and adult body mass as parameters for bug performance. Our results show that sequestration of glucosinolates by A. rosae only marginally affected the development of P. maculiventris. The effects of plant population on predator performance were variable. We suggest that sequestration of glucosinolates by A. rosae functions not only as a defensive mechanism against some predators, but may also be an alternative way of harmlessly dealing with plant allelochemicals.
Arbuscular mycorrhizal impacts on competitive interactions between Acacia etbaica and Boswellia papyrifera seedlings under drought stress
Birhane, E. ; Sterck, F.J. ; Bongers, F. ; Kuyper, T.W. - \ 2014
Journal of Plant Ecology 7 (2014)3. - ISSN 1752-9921 - p. 298 - 308.
interspecific competition - plant-growth - trade-offs - fungi - frankincense - infection - traits - associations - populations - coexistence
Aims Arbuscular mycorrhizal fungi can have a substantial effect on the water and nutrient uptake by plants and the competition between plants in harsh environments where resource availability comes in pulses. In this study we focus on interspecific competition between Acaia etbaica and Boswellia papyrifera that have distinctive resource acquisition strategies. We compared the extent of interspecific competition with that of intraspecific competition. Methods In a greenhouse study we examined the influence of Arbuscular Mycorrhiza (AM) and pulsed water availability on competitive interactions between seedlings of the rapidly growing species A. etbaica and the slowly growing species B. papyrifera. A factorial experimental design was used. The factors were AM, two water levels and five species combinations Important Findings Seedlings of both species benefitted from AM when grown alone, and the positive growth response to pulsed water availability in B. papyrifera seedlings was in contrast with the negative growth response for A. etbaica seedlings. AM also affected the competitive performance of both species. B. papyrifera was not affected by intraspecific competition, whereas A. etbaica was negatively affected compared to the seedlings grown alone. This effect was stronger in the presence of AM. In interspecific competition, A. etbaica outcompeted B. papyrifera. Mycorrhiza and pulsed water availability did not affect the outcome of interspecific competition, and the aggressivity index of A. etbaica remained unchanged. The extent to which AM influences plant competition in a drought-stressed environment may depend on belowground functional traits of the species. AM and pulsed water availability could modify the balance between intraspecific and interspecific competition. By affecting the balance between intraspecific and interspecific competition, both factors could impact the establishment and survival of seedlings.
Socio-Cultural and Economic Valuation of Ecosystem Services Provided by Mediterranean Mountain Agroecosystems
Bernues, A. ; Rodriguez-Ortega, T. ; Ripoll Bosch, R. ; Alfnes, F. - \ 2014
PLoS ONE 9 (2014)7. - ISSN 1932-6203
farming systems - natural park - trade-offs - conservation - landscape - europe - biodiversity - preferences - grassland - framework
The aim of this work was to elucidate the socio-cultural and economic value of a number of ecosystem services delivered by mountain agroecosystems (mostly grazing systems) in Euro-Mediterranean regions. We combined deliberative (focus groups) and survey-based stated-preference methods (choice modelling) to, first, identify the perceptions of farmers and other citizens on the most important ecosystem services and, second, to value these in economic terms according to the willingness to pay of the local (residents of the study area) and general (region where the study area is located) populations. Cultural services (particularly the aesthetic and recreational values of the landscape), supporting services (biodiversity maintenance) and some regulating services (particularly fire risk prevention) were clearly recognized by both farmers and citizens, with different degrees of importance according to their particular interests and objectives. The prevention of forest fires (
From coping to adaptation to economic and institutional change – Trajectories of change in land-use management and social organization in a Biosphere Reserve community, Mexico
Speelman, E.N. ; Groot, J.C.J. ; García-Barrios, L.E. ; Kok, K. ; Keulen, H. van; Tittonell, P.A. - \ 2014
Land Use Policy 41 (2014). - ISSN 0264-8377 - p. 31 - 44.
adaptive capacity - ecological systems - latin-america - power distribution - cover change - trade-offs - resilience - conservation - agriculture - vulnerability
Smallholder farming communities are increasingly affected by local impacts of international market dynamics, and (inter)governmental economic and nature conservation policies to which they respond through coping or adaptation. Although the attributes that underpin the capacity to adapt are widely agreed upon in literature, empirical evidence on how rural communities can develop adaptations are still scarce. Here, we provide such evidence based on a comprehensive driver-response reconstruction of a community in the buffer-zone of a Biosphere Reserve in Chiapas, Mexico. We found that coping (between 1990 and 2000) was gradually replaced by adaptations (1995–2010) based on: (i) diversification of land-use, (ii) improved social organization, (iii) improved communal decision-making, and (iv) more sustainable forms of land management. The diversification of local farming systems through inclusion of organic forest-based palm and coffee cultivation and the establishment of associated organizations, formed the basis of these changes. These adaptations were mainly supported by improved social, institutional and political capital. Communal forest resources, long-term support of an NGO and a highly motivated population, were essential circumstances that allowed these trajectories to develop. However, current unequal land and power distribution could undermine and debilitate adaptive capacity. Communities and supportive organizations need to be aware and capable to adjust continuously to prevent today's adaptation strategies from becoming tomorrow's coping responses.
A decision support tool for assessing scenario acceptability using a hierarchy of indicators with compensabilities and importance weights
Voet, H. van der; Heijden, G.W.A.M. van der; Kruisselbrink, J.W. ; Tromp, S.O. ; Rijgersberg, H. ; Bussel, L.G.J. van; Asselt, E.D. van; Fles-Klerx, H.J. van der - \ 2014
Ecological Indicators 43 (2014). - ISSN 1470-160X - p. 306 - 314.
sustainability indicators - engineering design - trade-offs - vikor - sum
Choosing between different scenarios commonly requires decision making based on multiple criteria. For example finding the most sustainable agricultural production system requires evaluation of many indicators in fields as diverse as environment, animal welfare and economics. A new and transparent method to such problems based on piecewise linear functions is described, and compared to other approaches. This paper presents a decision support tool which allows to (1) group indicators in a hierarchy, (2) define the acceptability of indicator values between unacceptable and desirable values, (3) define the relative importance of indicators, and (4) combine the individual indicators’ acceptabilities using various degrees of compromising into a final acceptability score for each of the investigated scenarios. The tool contains a visual module to study the comparison of scenarios in the bivariate case, which allows to get familiar with the concepts behind the balancing of indicators. The developed method and software tool are useful for decision support in processes where policy makers and scientists are interacting to arrive at optimal decisions