Records 1 - 20 / 255
Cats singing in the dark? Spawning aggregations of sound-producing fish in Amazonian floodplain forests
Sleen, Peter van der; Lugo-Carvajal, Arnold ; Zuanon, Jansen ; Holmgren, Milena - \ 2020
Environmental Biology of Fishes (2020). - ISSN 0378-1909
Amazon basin - Chorus - Freshwater fish - Gender segregation - Platydoras hancockii - Spawning aggregation
The Amazon basin has a freshwater fish diversity comparable to a tropical sea. Although many Amazonian fish species are popular ornamental fish across the world, the ecology of most species in their natural habitat remains poorly known (van der Sleen and Albert 2017). We report on shoaling behavior in Platydoras hancockii in a floodplain forest of the middle Rio Negro, Brazil. As the shoal consisted of only adult males, whereas gravid females were caught individually in nearby areas, we hypothesize that this aggregation may relate to spawning. Moreover, considering that Platydoras hancockii is capable of producing sounds, it is possible that these aggregations entail the formation of a chorus-like call with the function of attracting females from a larger area.
Influence of glacial sediments on the chemical quality of surface water in the Ulta valley, Cordillera Blanca, Peru
Magnússon, Rúna ; Cammeraat, Erik ; Lucke, Andreas ; Jansen, Boris - \ 2020
Journal of Hydrology (2020)587. - ISSN 0022-1694 - p. 1 - 16.
The Río Santa (Ancash, Peru) and its tributaries are an essential source of drinking and irrigation water. Its discharge relies on glacial meltwater, which is diminishing due to the rapid decrease in glacial extent. As a secondary effect, water quality can be compromised (e.g. pH < 3 and high concentrations of SO42− and trace metals). Although this has previously been attributed to pyrite rich Chicama bedrock exposed by glacial retreat, little is known about the occurrence of Chicama fragments in Quaternary glacial sediments and its influence on water quality. This research aims at elucidating this effect by relating observed changes in water quality in streams to presence and chemical composition of morainic ridges in the Quebrada Ulta in the Río Santa basin. Changes in water quality before and after contact with a morainic ridge were assessed using carbonate alkalinity titration, ion analysis and elemental analysis. Moreover, relative contributions of glacial meltwater and precipitation were assessed qualitatively using stable water isotope analysis. We used a novel method to explain the provenance of contaminated glacial sediments using a reconstruction of their source area. The mineralogical composition of a morainic ridge was strongly related to the geology of the source area indicating that mineralogical composition of tills may be predicted using this technique. Effects of glacial sediments in morainic ridges on water quality were minimal but depended on their mineralogical composition. Morainic ridges with a high content of Chicama shales tended to increase solute loads of Mg and SO42−. Additionally, isotope signatures suggest that during the dry season, moraines may act as reservoirs for precipitation-derived shallow groundwater. Clear trends in water quality were observed along the whole flow path of the Río Buín, which could potentially be explained by increased groundwater contribution downstream and shifts in dominant weathering mechanisms. Future research should focus on disentangling these various drivers of water quality in glacial catchments.
Designing future dairy systems for New Zealand using reflexive interactive design
Romera, A.J. ; Bos, A.P. ; Neal, M. ; Eastwood, C.R. ; Chapman, D. ; McWilliam, W. ; Royds, D. ; O'Connor, C. ; Brookes, R. ; Connolly, J. ; Hall, P. ; Clinton, P.W. - \ 2020
Agricultural Systems 181 (2020). - ISSN 0308-521X
Dairy - Design - Integral sustainability - Reflexion - Stakeholder - Territory
Globally, agricultural systems are facing unprecedented challenges. The problems are of systemic nature and will require transformational changes and systemic redesign. In this study, we investigated the redesign of dairy systems in New Zealand, due to their large economic, social and environmental influence nationally. We did not set the boundaries of the ‘dairy systems’ from the outset, letting this definition be part of the design process. We applied ‘Reflexive Interactive Design’ (RIO), an approach aimed at structurally addressing complex trade-offs and contributing, by process and design, to change towards sustainable development and integral sustainability (i.e. in all relevant dimensions of sustainability). A detailed system analysis was conducted, followed by two rounds of structured design focused on four main stakeholders (‘actors') identified as part of the RIO process: the farmers, the citizens, the consumers, and the dairy cows. Our study established design goals related to enhancing the wellbeing of humans and animals, enhancing environmental performance, economics and resilience of dairy systems and reconnecting dairy farming with the rest of society. The process took us beyond the boundaries of a dairy farm and identified the territorial level as the object of design, arriving at a design concept we have called the ‘Agro-ecological Park’. The name was chosen to convey an analogy with ‘Eco-industrial Parks’. Operating as a multifunctional network, the Park has the goal of delivering multiple benefits for its members, and multiple goods and services for the rest of society. The coordinated network articulates linkages between farmers and many other businesses and people in the territory. The individual dairy farm is redesigned to be a node in that network rather than operating as an isolated entity. That way, much of the weight for the increased complexity and multifunctionality now demanded of farming can be carried by the network instead of the individual farmer. These preliminary design ideas, and the reasoning behind them, should encourage new perspectives on the complex problems facing NZ dairy farming, and agriculture globally, in the upcoming decades.
Heat-induced changes in microstructure of spray-dried plant protein isolates and its implications on in vitro gastric digestion
Rivera del Rio, Andrea ; Opazo-Navarrete, Mauricio ; Cepero-Betancourt, Yamira ; Tabilo-Munizaga, Gipsy ; Boom, Remko M. ; Janssen, Anja E.M. - \ 2020
Food Science and Technology = Lebensmittel-Wissenschaft und Technologie 118 (2020). - ISSN 0023-6438
Gastric digestion - In vitro digestion - Pea protein isolate - Protein digestibility - Soy protein isolate - Spray-dried protein isolates
The quickly expanding field of plant-based food, generally uses protein concentrates or isolates as protein source. It is however not clear to what extent the intensive processing of these raw materials affects their digestibility. We here report on the in vitro gastric digestibility of the structures present in unheated and heated dispersions of spray-dried protein isolates of soybean and yellow pea. Unheated dispersions consist primarily of insoluble individual spray-dried particles, agglomerates of these and only a small fraction of soluble protein. Pepsin activity was followed in real-time through microscopic observations, showing the disassociation of agglomerates and inward-breakdown of individual particles, which are otherwise stable at gastric pH and ionic strength. This demonstrates that solubility is not necessarily an incentive for gastric protein digestion. Heating does not significantly affect the overall digestibility of protein isolate dispersions. Nevertheless, heating disrupts the structure of spray-dried particles, increasing the amount of smaller and better digestible particles that remain suspended after centrifugation. Conversely, heat-induced aggregates remain in the pellet and are up to 50% less digestible than their unheated counterparts. This impaired digestibility is counterbalanced by a reduced proportion of poorly-digestible species in the full system (up to 11% for soy and 23% for pea).
Educational hazards? The politics of disaster risk education in Rio de Janeiro
Coates, Robert - \ 2019
Disasters (2019). - ISSN 0361-3666
Outcomes of disaster education are highly dependent on the political context of that education. Based on a rich, in‐depth, case study of the creation of community monitors in a landslide and flood‐prone city in southeast Brazil, I demonstrate how political and developmental contexts add much additional nuance to existing theories of behaviourist and transformative education for preparedness and mitigation. Beyond identifying education's benefits, I argue that risk reduction outcomes are dependent on governance contexts that move over time. I demonstrate political complexity in the programme's implementation and cite the perspectives of a number of participants. Disaster education is shown to be the necessary yet underappreciated twin of technical and militarised approaches that dominate Brazilian disaster response. However, understated is education's situatedness: how it can become an arena of conflict between government and civil actors fighting over state and society in contexts of increasingly hazardous urbanization in Latin America.
|Heat-induced changes in microstructure of spray-dried plant protein isolates and its implications on in vitro gastric digestion
Rivera del Rio, Andrea - \ 2019
Modelling approaches for mixed forests dynamics prognosis. Research gaps and opportunities
Bravo, Felipe ; Fabrika, Marek ; Ammer, Christian ; Barreiro, Susana ; Bielak, Kamil ; Coll, Lluis ; Fonseca, Teresa ; Kangur, Ahto ; Löf, Magnus ; Merganičová, Katarina ; Pach, Maciej ; Pretzsch, Hans ; Stojanović, Dejan ; Schuler, Laura ; Peric, Sanja ; Rötzer, Thomas ; Río, Miren Del; Dodan, Martina ; Bravo-Oviedo, Andrés - \ 2019
Forest Systems 28 (2019)1. - ISSN 2171-5068 - 18 p.
Classification - Dynamics - Ecology - Empirical - Growth - Yield
Aim of study: Modelling of forest growth and dynamics has focused mainly on pure stands. Mixed-forest management lacks systematic procedures to forecast the impact of silvicultural actions. The main objective of the present work is to review current knowledge and forest model developments that can be applied to mixed forests. Material and methods: Primary research literature was reviewed to determine the state of the art for modelling tree species mixtures, focusing mainly on temperate forests. Main results: The essential principles for predicting stand growth in mixed forests were identified. Forest model applicability in mixtures was analysed. Input data, main model components, output and viewers were presented. Finally, model evaluation procedures and some of the main model platforms were described. Research highlights: Responses to environmental changes and management activities in mixed forests can differ from pure stands. For greater insight into mixed-forest dynamics and ecology, forest scientists and practitioners need new theoretical frameworks, different approaches and innovative solutions for sustainable forest management in the context of environmental and social changes.
Rethinking livestock production systems on the Galápagos Islands: Organizing knowledge-practice interfaces through reflexive interactive design
Puente-Rodríguez, Daniel ; Bos, Bram ; Groot Koerkamp, Peter W.G. - \ 2019
Environmental Science & Policy 101 (2019). - ISSN 1462-9011 - p. 166 - 174.
Galápagos Islands - Knowledge coproduction - Knowledge-practice interfaces - Livestock - Participatory methodologies - Reflexive interactive design
Different economic interests and frames of meaning around livestock production and environmental management usually lead to controversies. This is also the case on the Galápagos Islands. The literature usually focusses on Galápagos’ ecosystems and wildlife. However, less attention is given to livestock production systems on the archipelago. In this article, we introduce an initiative to redesign the livestock (i.e., pigs and poultry) production systems on the Galápagos Islands to achieve a higher degree of socio-ecological sustainability by deploying the first phase of the ‘reflexive interactive design’ (RIO) approach. On the basis of an interactive system analysis, this article answers the following question: What redesign options can be coproduced, and how, to enable a change towards sustainable livestock production systems? To analyse this (re)design process this article deploys and further elaborates the concept of knowledge-practice interfaces.
Grazing management for more resilient mixed livestock farming systems on native grasslands of southern South America
Modernel, Pablo ; Picasso, Valentin ; Carmo, Martin Do; Rossing, Walter A.H. ; Corbeels, Marc ; Soca, Pablo ; Dogliotti, Santiago ; Tittonell, Pablo - \ 2019
Grass and Forage Science 74 (2019)4. - ISSN 0142-5242 - p. 636 - 649.
drought - grazing management - livestock farming systems - native grasslands - resilience - Rio de la Plata grasslands
Droughts in southern South America affect grazing systems in many ways. They reduce biomass productivity; decrease livestock feed intake, weight and reproductive performance; increase farmers’ costs; and reduce farm income. It was hypothesized that simple grazing management variables affect the resilience of grazing systems to droughts at the paddock and farm scales. The effects of grazing management on herbage and animal production were assessed at paddock level, and how technological and structural variables relate to the production and economic performances at farm level. Results of a grazing experiment controlling herbage allowance at paddock level showed that resistance of herbage accumulation and animal live weight to drought was significantly higher for paddocks with higher pre-drought herbage allowance than for those managed to low herbage allowance treatments. A strong positive linear relationship was found between pre-drought herbage height and resistance of herbage accumulation rate (p <.01). In a longitudinal study of nine farms in Uruguay, resistance of cow pregnancy rate to drought was positively correlated with cow pregnancy rate (r =.72, p =.02) and farm net income (r =.78, p =.02), and negatively correlated with sheep-to-cattle ratio (r = −.80, p =.01). These correlations suggest that farms with higher incomes and low proportions of sheep in the herd withstand drought better (in terms of pregnancy rate). Four common regional production strategies were identified that react differently when farmers face drought, and these results can aid farmers in those regions to design more resilient mixed livestock farming systems and can inform policymakers about effective strategies for mitigating drought impacts in the region.
The RIO approach: Design and anchoring of sustainable animal husbandry systems
Elzen, Boelie ; Bos, Bram - \ 2019
Technological Forecasting and Social Change 145 (2019). - ISSN 0040-1625 - p. 141 - 152.
Anchoring of sustainable innovations - Animal husbandry - Reflexive Interactive Design (RIO) - Sustainable design - Transition stimulation
This paper discusses an approach to develop new ‘integrally sustainable’ animal production systems and stimulate their uptake in practice. It consists of a design approach called RIO, and a set of ‘anchoring’ activities to stimulate their uptake in niches and in the regime. In the period 2001–2015 we have applied the approach in various animal production sectors, and adapted and improved it while doing. The general aim of the paper is to assess the applicability of the RIO/anchoring approach to induce sustainability transitions. We conclude that RIO is especially suited for areas characterized by a ‘heterogeneous’ set of sustainability challenges (in our case, environmental burden, animal welfare, public acceptance, profitability). A RIO approach can then render ‘integrally sustainable’ alternatives that generate wide interest in the regime. Anchoring activities can successfully stimulate a variety of initial changes. This does not suffice, however, and a conducive institutional environment is key to facilitate the initial uptake of the novel systems. With relatively simple and cheap financial instruments, governments can help to create such a conducive environment.
Aplicación de tomografías de resistividad eléctrica para delinear la hidrogeología del permafrost en el área de la cabecera del río Amarillo en Qinghai-Tibet Plateau, suroeste de China
Gao, Shuhui ; Jin, Huijun ; Bense, Victor F. ; Wang, Xinbin ; Chai, Xiaojun - \ 2019
Hydrogeology Journal 27 (2019)5. - ISSN 1431-2174 - p. 1725 - 1737.
China - Electrical resistivity tomography - Hydraulic properties - Hydrogeology - Permafrost
Hydrogeologic processes and shallow subsurface flows control runoff generation, groundwater dynamics, and permafrost distribution at high latitudes and elevations. Electrical resistivity tomography (ERT) can effectively delineate the frozen and thawed zones in the cold environment and can be applied in permafrost hydrogeology by measuring the differences in subsurface electrical potential. A combined approach of ERT and borehole measurements is implemented to map the flow paths of the supra-permafrost and sub-permafrost waters around the Wanlong Worma Lake (WWL) basin in the headwaters of the Yellow River (northeastern Qinghai-Tibet Plateau, China). The ERT sounding results are further validated using drilling records and measured data on ground temperatures and groundwater level. Then, basic features for permafrost hydrogeology are outlined according to the ERT sounding, vegetation distribution, and geological data in the WWL basin. The results show the presence of permafrost at depths up to 15 m, in which electrical resistivity is >250 Ωm. Below the permafrost (at depth 15–80 m), electrical resistivity is generally <100 Ωm. At the depth where an aquifer occurs (20–60 m), electrical resistivity is in the range 1–25 Ωm. The sub-permafrost water moves towards the zone of taliks (unfrozen ground) under the hydraulic gradient controlled by local permafrost distribution and is affected by terrain relief. This work demonstrates the capability of ERT for delineating the distribution of the aquifers of the supra- and sub-permafrost waters and for understanding changes in hydraulic connections in a rapidly degrading alpine permafrost basin.
Mobilizing water actors and bodies of knowledge. The multi-scalar movement against the Río Grande Dam in Málaga, Spain
Duarte-Abadía, Bibiana ; Boelens, R.A. ; Pré, Lucas Du - \ 2019
Water 11 (2019)3. - ISSN 2073-4441 - 21 p.
Just as in other parts of Spain, the Guadalhorce Valley, Málaga, has a long history of policies based on ‘hydraulic utopianism’ (regenerationist and Franco-ist), bent on ‘reorganizing’ political, geographic, and human nature. Residents of the neighboring sub-basin, the Río Grande valley, have seen how these policies, designed to transfer rural water to modern urban centers, have turned the Guadalhorce hydrosocial territory into a ‘hydraulic dystopia’. In this article, we examine how Río Grande valley residents mobilized to maintain control over the development and use of their resources, livelihoods, and knowledge systems, when modernist-urbanist policies planned to take their water from a major dam on the Río Grande. Interviewing actors at different scales we examined how this anti-dam movement organized massively in a creative, multi-actor, and multi-scale network. Our results also show that this unified, successful fight against the ‘common enemy’, the mega-hydraulic construction, has become more complex, as threats crop up not only from the ‘city over there’ but also from ‘internal’ hydro-territorial transformations. These sprout from policies to modernize traditional irrigation systems, supposedly to ‘save water’, but critical voices assume that it is all about passing on the ‘surplus’ to Málaga city, or using that water to expand agribusiness. We conclude that the challenge lies in critically integrating multiple forms of knowledge, stakeholders, and scales to both defend collective water management and creatively construct anti-hegemonic alternatives.
|The Rio das Velhas Watershed Case Study, Minas Gerais, Brazil : Towards new water management participatory approaches
Teodoro, Hildeano Delanusse ; Warner, J.F. - \ 2018
NBC-Periódico Científico Do Núcleo De Biociências 8 (2018)15. - ISSN 2238-1945
The present work was carried out in order to discover the possibilities over the increment of new approaches concerning water resources management based on the social and institutional actors participation. To do so, the River Basin Watershed Committee (CBHRV, in Portuguese), located in the state of Minas Gerais, Brazil, was used as a case study. This committee is recognized nationally and internationally both for its conception history, as well as for its organization and established partnerships with the public and private sectors. The research shows that innumerable factors must be considered in public policies to increase the social participation in long term. Among them, the technical chambers, governmental support and approach with the private initiative for the establishment of integrated planning in the river basin stand out. In this direction, the knowledge of the institutional elements characteristic of the object of research, as well as the local political arrangements is fundamental for the consolidation of participatory approaches.
Sensibilidad y escenarios de disponibilidad de agua para consumo humano en la microcuenca del río Porrosatí, Heredia, Costa Rica
Montero-sánchez, Esteban ; Herrera-murillo, Jorge ; Ramírez-granados, Pablo - \ 2018
Revista Geográfica de América Central 1 (2018)62. - ISSN 1011-484X - p. 52 - 75.
La variabilidad climática y el cambio del uso de la tierra representan una de las mayores condicionantes para la disponibilidad de agua para consumo humano en el futuro. Con el objetivo de analizar la disponibilidad de agua para uso y consumo humano en la microcuenca del río Porrosatí, se calcularon balances hídricos con base en la recarga de agua subterránea. Para las estimaciones se utilizaron registros meteorológicos de 15 años, en el periodo comprendido entre el año 2000 a 2014, y análisis de las características hidrológicas. Con el fin de realizar escenarios de recarga hídrica en el mediano (2026-2030) y largo plazo (2051-2055), tomando en consideración escenarios y por el cambio climático se utilizaron las predicciones de variación de temperatura y precipitación elaborados por el Instituto Meteorológico Nacional, bajo un escenario de emisiones A2. Los resultados obtenidos muestran comportamientos atípicos con cambios significativos en el comportamiento estacional de la recarga. Los volúmenes proyectados a futuro dan cuenta de importantes disminuciones, que en algunos casos superan el 15% como media llegando hasta diferencias del 50%. En el escenario de largo plazo se notó un importante cambio en comportamiento estacional, dando como resultado la aparición de dos picos de recarga. Las proyecciones climáticas presentan un escenario complejo con limitaciones a la recarga hídrica de agua subterránea y, por ende, a la disponibilidad de agua para consumo humano en el mediano y largo plazo.
Alianzas antiembalse y luchas hidroepistemológicas. Los retos de la gestión colectiva del agua en el Río Grande, Málaga, España
Duarte-Abadía, Bibiana ; Boelens, R.A. ; Pré, Lucas Du - \ 2018
Cuadernos de Geografia 101 (2018). - ISSN 0210-086X - p. 107 - 126.
In this article, we analyze the water knowledge struggles and challenges that the Rio Grande sub-basin’s social movement has faced when encountering the different modernistic projects that seek to transfer rural water to Malaga city. The first relates to a large dam construction, the second to the modernization of traditional irrigation systems. We conclude that the movement’s challenges are to unpack the truth regimes that support these hydraulic-modernistic projects, to claim for collective water use and control, and to engage in a bottom-up «commoning» process for defending the river’s socio-environmental values, cultural-economic importance, and epistemological meaning and existence.
|Maternal effects in a placental live-bearing fish
Hagmayer, A. ; Furness, Andrew I. ; Reznick, D.N. ; Pollux, B.J.A. - \ 2018
Maternal effects often provide a mechanism for adaptive transgenerational phenotypic plasticity. The maternal phenotype can profoundly influence the potential for environmentally-induced adjustments of the offspring phenotype, causing correlations between offspring and maternal traits.
We studied the effects of maternal phenotype on offspring phenotype prior to and during the pregnancy in the placental live-bearing fish species Poeciliopsis retropinna collected from the Rio Terraba in Costa Rica. Specifically, we examined how maternal traits such as body fat, lean mass and length influence pre- and post-fertilization maternal provisioning and how this ultimately affects offspring size and body composition at birth.
We found that maternal length proportionally increases egg mass at fertilization and offspring mass at birth, whereas maternal body fat increases offspring mass at birth but does not affect egg mass at fertilization. We furthermore found temporal variation in embryo composition during gestation, with females investing first in embryo somatic lean mass and allocating fat reserves to the embryos only very late in pregnancy. This delay in fat allocation is arguably adaptive, because it postpones an unnecessary high reproductive burden to the mother to late pregnancy. We conclude that offspring provisioning is a plastic phenotypic trait that is strongly determined by maternal phenotype.
the Rio Pavilion during the 14th Conference of the Parties to the CBD
Karlsson-Vinkhuyzen, Sylvia - \ 2018
Co-organising and co-facilitating a full day program in the Rio Pavillion during the 14th Conference of the Parties to the CBD (The Convention on Biological Diversity). This full day side-event included presentations of the expert group’s work including our new framework for scenario development and then three rounds of 90 min workshops on the urban, rural and marine context. In each workshop I introduced the exercise of developing scenarios linked to one particular value framework - and facilitated one of the group’s work. The day ended with a concluding plenary, in which I took part, exploring the potential value of the work of the expert group for the work on a new strategic plan for the CBD. The whole event was well-documented in the Earth Negotiations Bulletin and thus distributed to a big audience, see http://enb.iisd.org/download/pdf/sd/enbplus200num42e.pdf
In addition I contributed to panels in two other side-events during the COP, one focused on transformative scenarios and the other one on governance.
Model-Data comparison: The Late Pleistocene and Holocene evolution of the Rio Bergantes catchment, Spain
Mather, A.E. ; Armitage, J. ; Attal, M. ; Benito, G. ; Brewer, P. ; Briant, B. ; Cohen, K. ; Coulthart, T. ; Gorp, W. van; Macklin, M. ; Schoorl, J.M. - \ 2018
In: Book of abstracts QRA Annual Discussion Meeting 2018. - Plymouth : Plymouth University - p. 71 - 71.
Livestock farming systems on South American native grasslands: when production meets conservation
Modernel, Pablo - \ 2018
Wageningen University. Promotor(en): P.A. Tittonell, co-promotor(en): M. Corbeels; W.A.H. Rossing; S. Dogliotti Moro. - Wageningen : Wageningen University - ISBN 9789463435291 - 237
The livestock industry faces the double challenge of coping with the increasing demand for animal protein and reducing its high load on the environment. On the one hand, livestock has been recognized for its contribution to the economy, providing 40% of global agricultural GDP, ensuring a living for farmers, maintaining rural heritage and traditional farming landscapes, providing draft power, fuel, and sources of nutrients, particularly proteins. On the other hand, the livestock industry emits 13-18% of global greenhouse gas emissions, occupies 33% of total arable land and is responsible for 8% of global water use.
South American Río de la Plata grasslands comprise more than 500,000 km2, including all of Uruguay, north-eastern Argentina and southern Brazil. These grasslands provide feed for 43 million heads of cattle and 14 million sheep. The biome is habitat of 4000 native plant species, 300 species of birds, 29 species of mammals, 49 species of reptiles and 35 species of amphibians. They store 5% of the total soil organic carbon stock of Latin America on 3% of the area, and they protect soils from erosion. Cropping areas and livestock herds have shifted spatially. Regions that used to integrate crop-livestock systems have specialized in cropping, decreasing stocks but increasing beef confined systems (feedlots). Regions with historical predominance of cattle due to low-potential productive have been increasing in stocking rates which could aggravate overgrazing problems. Land-use change very likely increased provisioning services while very likely decreased supporting and regulating services. Overgrazing regimes with low forage allowances were predominantly associated with negative effects on provisioning and supporting and regulating ecosystem services. The most documented impacts of land use-change and overgrazing include: reducing soil organic carbon stocks and the diversity of plants, birds and mammals, and increasing soil erosion.
In order to identify the diversity in farming systems, the first biome-wide beef farm typology of the Rio de la Plata grasslands was constructed. While seven farm types were identified, most of the farms belonged to the family farms, with cow-calf operations using native grasslands. We identified positive deviant farms, which performed excellently in economic and environmental terms when compared to the other farms in the region, and, more generally, to farms from OECD countries. These positive deviant farmers achieved 192 kg LW ha-1 yr-1 or 201 US$ ha-1 year-1 with negligible fossil energy consumption and phosphorus surplus, low carbon footprint (13 kg CO2 eq kg LW-1) and having over 95% of their land under native grassland. This means that the native grassland-based farming systems of the Río de la Plata grasslands region have the potential to produce high-quality beef with low use of inputs and preserve biodiversity, thus constituting one of the most sustainable livestock farming system models. However, the greenhouse gas emissions per unit of product may be high when compared to other forms of protein production as a consequence of the digestive system of the ruminant.
Droughts may affect grazing systems at multiple levels: they reduce plant growth and biomass production, decrease intake, weight, and reproductive performance of livestock, increase costs and reduce income for farmers, and affect rural communities and even countries’ economies. The relationship between management and resilience to drought at paddock and farm level was studied. At paddock level, higher herbage allowance increased the resistance of herbage accumulation rate and animal weight. A positive relationship was found between pre-drought herbage height and resistance of herbage accumulation to drought, which means that herbage height can be used as a guideline for grassland management. The sheep to cow ratio was negatively correlated with pregnancy rate of cows, a key variable defining meat production and farm income.
The economic and environmental issues with livestock production systems discussed above demand local actions by stakeholders. One such action is to actively work on the redesign of individual farms, to improve farmer livelihoods and ecosystem service provision. To aid this process we present and evaluate a dynamic whole-farm simulation model (PASpALuM). The model elucidates the relations between grazing management, productivity and environmental impact. The herbage dynamics module was evaluated against experimental data, showing acceptable simulation of the seasonal dynamics of herbage height and mass. A simulation exercise explored the effect of grazing management on enteric methane emissions and soil organic carbon from 2007 to 2009.
Maintaining this example of nature inclusive agriculture and improving it to the level of agriculture-inclusive nature, seems possible by changing grassland management strategies. Contributions to greenhouse gas emissions by livestock will remain, but this should be seen as the price to be paid for maintaining a unique and priceless biome that cannot be maintained in another way than through low-intensity grazing by ruminants. The contribution of greenhouse gas emissions from livestock systems on native grasslands is determined by the carrying capacity of the grasslands and will remain much lower per hectare than that of intensive pastures. Solutions for global meat production should be considered within social and ecological boundaries. Such quest is not advanced by unilateral reliance on one size fits all efficiency measures.
Species mixing effects on forest productivity : A case study at stand-, species- and tree-level in the Netherlands
Lu, Huicui ; Mohren, Godefridus M.J. ; Río, Miren del; Schelhaas, Mart-Jan ; Bouwman, Meike ; Sterck, Frank J. - \ 2018
Forests 9 (2018)11. - ISSN 1999-4907
Basal area increment - Inter- and intra-specific competition - Mixed forest - Overyielding - Periodic annual volume increment
Many monoculture forests have been converted to mixed-species forests in Europe over the last decades. The main reasons for this conversion were probably to increase productivity, including timber production, and enhance other ecosystem services, such as conservation of biodiversity and other nature values. This study was done by synthesizing results from studies carried out in Dutch mixed forests compared with monoculture stands and evaluating them in the perspective of the current theory. Then we explored possible mechanisms of higher productivity in mixed stands, in relation to the combination of species, stand age and soil fertility, and discussed possible consequences of forest management. The study covered five two-species mixtures and their corresponding monoculture stands from using long-term permanent forest plots over multiple decades as well as two inventories (around 2003 and 2013) across the entire Netherlands. These forest plot data were used together with empirical models at total stand level, species level and tree level. Overyielding in Douglas-fir-beech and pine-oak mixtures was maintained over time, probably owing to the intensive thinning and was achieved on the poorer soils. However, this overyielding was not always driven by fast-growing light-demanding species. On individual tree level, intra-specific competition was not necessarily stronger than inter-specific competition and this competitive reduction was less seen at lower soil fertility and dependent on species mixtures. Moreover, size-asymmetric competition for light was more associated with tree basal area growth than size-symmetric competition for soil resources. Overall, this study suggests a substantial potential of species mixing for increasing productivity and implies developing forest management strategies to convert monospecific forests to mixed-species forests that consider the complementarity in resource acquisition of tree species.