scholarly journals A coupled forage-grazer model predicts viability of livestock production and wildlife habitat at the regional scale

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Virginia A. Kowal ◽  
Sharon M. Jones ◽  
Felicia Keesing ◽  
Brian F. Allan ◽  
Jennifer M. Schieltz ◽  
...  

AbstractInformed management of livestock on rangelands underpins both the livelihoods of communities that depend on livestock for sustenance, and the conservation of wildlife that often depend on livestock-dominated landscapes for habitat. Understanding spatial patterns of rangeland productivity is therefore crucial to designing global development strategies that balance social and environmental benefits. Here we introduce a new rangeland production model that dynamically links the Century ecosystem model with a basic ruminant diet selection and physiology model. With lightweight input data requirements that can be met with global sources, the model estimates the viability of broad livestock management decisions, and suggests possible implications of these management decisions for grazing wildlife. Using minimal field data, the new rangeland production model enables the reliable estimation of cattle stocking density; this is an important predictor of the viability of livestock production and forage available for grazing wildlife.

2021 ◽  
Vol 5 ◽  
Author(s):  
Mark P. Johnson

Like many sectors, the expansion of aquaculture has issues related to sustainable resource use and environmental change. These challenges are widely recognised and are addressed with sectoral strategies. Even when culturing a single species, the specifics of impacts, constraints, and pressures are likely to vary in effects for different farm types. On the other hand, production efficiencies can drive farms towards homogeneity. A simple model is used in this study to demonstrate farm-scale budgets and the pressure to intensify production towards an optimum. A range of interventions can provide incentives for less intensive production: these include price premiums and altered cost bases. Integrated multitrophic aquaculture (IMTA) does not offer a route to less intensive production systems if the productivity of the extractive species (e.g., algae) is linked to the intensity of the fish farm, although alternative incentives for IMTA are possible. Increases in the intensity of production (as stocking density) can be mitigated by increasing farm capacity. An expanded production model suggests that this will lead to larger farms at relatively high stocking densities. Where farms are subject to variable economic and biological processes, this can lead to some combinations of intensity and capacity to have less variable earnings than others. The promotion of diverse aquaculture sectors may allow some of the ecological and social synergies available to smaller farms to be combined at a regional scale with the greater production of large farms. Cost, price and/or regulatory incentives are needed to create diverse production systems.


2017 ◽  
Vol 6 (2) ◽  
pp. 66 ◽  
Author(s):  
Maria Storrle ◽  
Hans-Jorg Brauckmann ◽  
Gabriele Broll

This study investigates the amounts of greenhouse gas (GHG) emissions due to manure handling within different livestock production systems in Tyumen oblast of Western Siberia. Tyumen oblast occupies approx. 160 000 km² of Asian taiga and forest steppe. The amount of GHGs from manure was calculated as a function of the handling according to current IPCC guidelines for ecozones and livestock production systems. The entire Tyumen oblast has annual 7 400 t methane emissions and 440 t nitrous oxide emissions from manure. Three livestock production systems are prevalent in Tyumen oblast: Mega farms, small farms and peasant farms. The share of mega farms is 81 % (171 kt CO2 eq). Additionally, the slurry system in mega farms causes environmental pollution. GHG emissions and environmental pollution could be reduced by implementing solid manure systems or pasturing, by installing storage facilities for slurry outside the stables and through application of the manure as fertiliser at mega farms. In small farms solid manure systems and a small stocking density of livestock lead to smallest GHG emissions (1 %, 3 kt CO2 eq) from manure. In peasant farming 18 % (38 kt CO2 eq) of GHGs are emitted due to pasturing. 


2009 ◽  
Vol 6 (1) ◽  
pp. 124-127 ◽  
Author(s):  
Henrik Sparholt ◽  
Robin M. Cook

The theory of maximum sustainable yield (MSY) underpins many fishery management regimes and is applied principally as a single species concept. Using a simple dynamic biomass production model we show that MSY can be identified from a long time series of multi-stock data at a regional scale in the presence of species interactions and environmental change. It suggests that MSY is robust and calculable in a multispecies environment, offering a realistic reference point for fishery management. Furthermore, the demonstration of the existence of MSY shows that it is more than a purely theoretical concept. There has been an improvement in the status of stocks in the Northeast Atlantic, but our analysis suggests further reductions in fishing effort would improve long-term yields.


2010 ◽  
Vol 3 (1) ◽  
pp. 1-11 ◽  
Author(s):  
Paul O. Downey ◽  
Moira C. Williams ◽  
Leonie K. Whiffen ◽  
Bruce A. Auld ◽  
Mark A. Hamilton ◽  
...  

AbstractRecognition that alien plants pose a significant threat to biodiversity has not always translated into effective management strategies, policy reforms, and systems to establish priorities. Thus, many alien plant management decisions for the protection of biodiversity occur with limited knowledge of what needs to be protected (other than biodiversity in a generalized sense) or the urgency of actions. To rectify this, we have developed a triage system that enables alien plant management decisions to be made based on (1) the urgency of control relative to the degree of threat posed to biodiversity, compared with (2) the likelihood of achieving a successful conservation outcome as a result of alien plant control. This triage system is underpinned by a two-step approach, which identifies the biodiversity at risk and assesses sites to determine priorities for control. This triage system was initially developed to manage the threat posed by bitou bush to native species in New South Wales (NSW), Australia. It has subsequently been improved with the national assessment of lantana in Australia, and the adaptation from a single to multiple alien plant species approach on a regional scale. This triage system identifies nine levels of priority for alien plant management aimed at biodiversity conservation, ranging from immediate, targeted action to limited or no action. The development of this approach has enabled long-term management priorities to be set for widespread alien plants that are unlikely to be eradicated. It also enables control to occur in a coordinated manner for biodiversity conservation at a landscape scale, rather than as a series of individual unconnected short-term actions.


2018 ◽  
Author(s):  
Ute Daewel ◽  
Corinna Schrum ◽  
Jed Macdonald

Abstract. Coupled physical-biological models usually resolve only parts of the trophic food chain and hence, run the risk of neglecting relevant ecosystem processes. Additionally, this imposes a closure term problem at the respective “ends” of the considered trophic levels. Here we propose a consistent NPZD-Fish modelling approach (ECOSMO E2E) to address the above-mentioned problem in lower trophic ecosystem modelling, and to understand how the implementation of higher trophic levels in a NPZD model affects the simulated response of the combined North Sea and Baltic Sea ecosystem. On the basis of the coupled ecosystem model ECOSMO II we implemented one functional group that represents fish and one group representing macrobenthos in the 3d model formulation. Both groups are linked to the lower trophic levels and to each other via predator-prey relationships. The model allows investigating bottom-up impacts on primary and secondary production and cumulative fish biomass dynamics, but also top-down mechanisms on the lower trophic level production. Model results for a ten-year long simulation period (1980–1989) were analysed and discussed with respect to the observed pattern. To address the relevance of the newly implemented trophic levels for the simulated model response, we compare the performance of the ECOSMO E2E to a respective truncated NPZD model (ECOSMO II), which simulated the same time period. Additionally, we performed scenario tests to analyse the new role of the zooplankton mortality closure term in the truncated NPZD and the fish mortality term in the end-to-end model, which summarizes pressure imposed on the system by fisheries and mortality imposed by apex predators. We found that the model-simulated macrobenthos and fish spatial and seasonal pattern agree well with current system understanding. Considering a dynamic fish component in the ecosystem model resulted in slightly improved model performance with respect to representation of spatial and temporal variations in nutrients, changes in modelled plankton seasonality and nutrient profiles. Model sensitivity scenarios showed that changes in the zooplankton mortality parameter are transferred up and down the trophic chain with little attenuation of the signal, while major changes in fish mortality and in fish biomass cascade down the food chain.


2019 ◽  
Vol 12 (3) ◽  
pp. 1029-1066 ◽  
Author(s):  
Lluís Fita ◽  
Jan Polcher ◽  
Theodore M. Giannaros ◽  
Torge Lorenz ◽  
Josipa Milovac ◽  
...  

Abstract. The Coordinated Regional Climate Downscaling Experiment (CORDEX) is a scientific effort of the World Climate Research Program (WRCP) for the coordination of regional climate initiatives. In order to accept an experiment, CORDEX provides experiment guidelines, specifications of regional domains, and data access and archiving. CORDEX experiments are important to study climate at the regional scale, and at the same time, they also have a very prominent role in providing regional climate data of high quality. Data requirements are intended to cover all the possible needs of stakeholders and scientists working on climate change mitigation and adaptation policies in various scientific communities. The required data and diagnostics are grouped into different levels of frequency and priority, and some of them even have to be provided as statistics (minimum, maximum, mean) over different time periods. Most commonly, scientists need to post-process the raw output of regional climate models, since the latter was not originally designed to meet the specific CORDEX data requirements. This post-processing procedure includes the computation of diagnostics, statistics, and final homogenization of the data, which is often computationally costly and time-consuming. Therefore, the development of specialized software and/or code is required. The current paper presents the development of a specialized module (version 1.3) for the Weather Research and Forecasting (WRF) model capable of outputting the required CORDEX variables. Additional diagnostic variables not required by CORDEX, but of potential interest to the regional climate modeling community, are also included in the module. “Generic” definitions of variables are adopted in order to overcome the model and/or physics parameterization dependence of certain diagnostics and variables, thus facilitating a robust comparison among simulations. The module is computationally optimized, and the output is divided into different priority levels following CORDEX specifications (Core, Tier 1, and additional) by selecting pre-compilation flags. This implementation of the module does not add a significant extra cost when running the model; for example, the addition of the Core variables slows the model time step by less than a 5 %. The use of the module reduces the requirements of disk storage by about a 50 %. The module performs neither additional statistics over different periods of time nor homogenization of the output data.


2019 ◽  
Vol 35 (6) ◽  
pp. 663-677 ◽  
Author(s):  
Andrés Horrillo ◽  
Paula Gaspar ◽  
Francisco J. Mesías ◽  
Ahmed Elghannam ◽  
Miguel Escribano

AbstractThe dehesa agroforestry system is classified as one of the most singular ecosystems in the European Union. In the southwest of the Iberian Peninsula, it spreads over an area of approximately 6.7 million hectares, contributing major environmental, cultural, aesthetic and economic value to the region. The main agricultural activity that is developed in this ecosystem is the extensive farming of cattle, sheep and Iberian pigs with low stocking density and few inputs. Sustainable management of these ecosystems' existing production farms is essential in order to secure their continuity, as they face a difficult situation on account of their low profitability. One of the strategies that could be employed to attain a sustainable situation is the proposition of an organic production model. In order to explore this option, a participatory research process has been proposed and developed in the Spanish region called Extremadura (Spain). The aim of this process is to investigate the potential of extensive farming systems in moving toward a sustainable organic production model, identifying the main barriers preventing livestock farmers from converting to the organic model and seeking specific improvement measures that would reduce such barriers. For that purpose, four focus group sessions were run with a total of 33 participating stakeholders. For the analysis of these focus groups, Atlas.ti qualitative software was used to categorize and quantify the main ideas proposed during the sessions. The findings revealed that the main barriers can be classified into three groups: barriers that are inherent to the production processes and the structure of the specific sector, barriers associated with administration and management issues and lastly, barriers relating to education and training of the various actors involved. We consider this paper may contribute to policy makers' decisions to focus on specific actions for improvement that are customized for the socio-economic and environmental conditions of the region.


2007 ◽  
Vol 36 (2) ◽  
pp. 267-280 ◽  
Author(s):  
LeRoy Hansen

This paper presents the methodology, assumptions, and data used to generate regional and national environmental benefit estimates of the USDA's Conservation Reserve Program (CRP). It's assumed that, without the program, production and conservation practices on CRP lands would be the same as those used on surrounding lands. When range and forest lands are (are not) included as land-use options, 54 (71) percent of the CRP land would be in crop production—which is consistent with past analyses. Soil erosion would be 222 to 248 million tons per year—about 11 percent—higher than the current level. Benefits are estimated by applying environmental benefit models, estimated in previous analyses, to the CRP's estimated effect on erosion and wildlife habitat. Nationally, the CRP is estimated to provide $1.3 billion in annual benefits, which represents 75 to 80 percent of the program's cost. In seven of the 10 USDA Farm Production Regions, the CRP's environmental benefits exceed costs. Thus, reallocating acreage to these regions could increase net program benefits. However, because many benefits could not be estimated, one cannot conclude that regional and national benefits do not exceed costs.


Author(s):  
Serap Göncü ◽  
Cahide Dede ◽  
Özgül Anitaş ◽  
Sibel Bozkurt ◽  
Mustafa Güçlü Sucak

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