Integrating pests and pathogens into the climate change/food security debate
TL;DR: More mechanistic inclusion of pests and pathogen effects in crop models would lead to more realistic predictions of crop production on a regional scale and thereby assist in the development of more robust regional food security policies.
Abstract: While many studies have demonstrated the sensitivities of plants and of crop yield to a changing climate, a major challenge for the agricultural research community is to relate these findings to the broader societal concern with food security. This paper reviews the direct effects of climate on both crop growth and yield and on plant pests and pathogens and the interactions that may occur between crops, pests, and pathogens under changed climate. Finally, we consider the contribution that better understanding of the roles of pests and pathogens in crop production systems might make to enhanced food security. Evidence for the measured climate change on crops and their associated pests and pathogens is starting to be documented. Globally atmospheric [CO(2)] has increased, and in northern latitudes mean temperature at many locations has increased by about 1.0-1.4 degrees C with accompanying changes in pest and pathogen incidence and to farming practices. Many pests and pathogens exhibit considerable capacity for generating, recombining, and selecting fit combinations of variants in key pathogenicity, fitness, and aggressiveness traits that there is little doubt that any new opportunities resulting from climate change will be exploited by them. However, the interactions between crops and pests and pathogens are complex and poorly understood in the context of climate change. More mechanistic inclusion of pests and pathogen effects in crop models would lead to more realistic predictions of crop production on a regional scale and thereby assist in the development of more robust regional food security policies.
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TL;DR: It is argued that nascent fungal infections will cause increasing attrition of biodiversity, with wider implications for human and ecosystem health, unless steps are taken to tighten biosecurity worldwide.
Abstract: The past two decades have seen an increasing number of virulent infectious diseases in natural populations and managed landscapes. In both animals and plants, an unprecedented number of fungal and fungal-like diseases have recently caused some of the most severe die-offs and extinctions ever witnessed in wild species, and are jeopardizing food security. Human activity is intensifying fungal disease dispersal by modifying natural environments and thus creating new opportunities for evolution. We argue that nascent fungal infections will cause increasing attrition of biodiversity, with wider implications for human and ecosystem health, unless steps are taken to tighten biosecurity worldwide.
2,408 citations
TL;DR: In this paper, a comprehensive summary of studies that simulate climate change impacts on agriculture are reported in a meta-analysis, which suggests that aggregate yield losses should be expected for wheat, rice and maize in temperate and tropical growing regions even under relatively moderate levels of local warming.
Abstract: A comprehensive summary of studies that simulate climate change impacts on agriculture are now reported in a meta-analysis. Findings suggest that, without measures to adapt to changing conditions, aggregate yield losses should be expected for wheat, rice and maize in temperate and tropical growing regions even under relatively moderate levels of local warming.
1,458 citations
TL;DR: This work proposes a framework based on ideas from global-change biology, community ecology, and invasion biology that uses community modules to assess how species interactions shape responses to climate change.
Abstract: Predicting the impacts of climate change on species is one of the biggest challenges that ecologists face Predictions routinely focus on the direct effects of climate change on individual species, yet interactions between species can strongly influence how climate change affects organisms at every scale by altering their individual fitness, geographic ranges and the structure and dynamics of their community Failure to incorporate these interactions limits the ability to predict responses of species to climate change We propose a framework based on ideas from global-change biology, community ecology, and invasion biology that uses community modules to assess how species interactions shape responses to climate change
1,169 citations
01 Jan 2014
TL;DR: The questions for this chapter are how far climate and its change affect current food production systems and food security and the extent to which they will do so in the future.
Abstract: Many definitions of food security exist, and these have been the subject of much debate. As early as 1992, Maxwell and Smith (1992) reviewed more than 180 items discussing concepts and definitions, and more definitions have been formulated since (DEFRA, 2006). Whereas many earlier definitions centered on food production, more recent definitions highlight access to food, in keeping with the 1996 World Food Summit definition (FAO, 1996) that food security is met when “all people, at all times, have physical and economic access to sufficient, safe, and nutritious food to meet their dietary needs and food preferences for an active and healthy life.” Worldwide attention on food access was given impetus by the food “price spike” in 2007–2008, triggered by a complex set of long- and short-term factors (FAO, 2009b; von Braun and Torero, 2009). FAO concluded, “provisional estimates show that, in 2007, 75 million more people were added to the total number of undernourished relative to 2003–05” (FAO, 2008); this is arguably a low-end estimate (Headey and Fan, 2010). More than enough food is currently produced per capita to feed the global population, yet about 870 million people remained hungry in the period from 2010 to 2012 (FAO et al., 2012). The questions for this chapter are how far climate and its change affect current food production systems and food security and the extent to which they will do so in the future (Figure 7-1).
960 citations
Cites background from "Integrating pests and pathogens int..."
...The potential influence of pests and diseases is commonly beyond the scope of such studies (Gregory et al., 2009)....
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TL;DR: This paper reviews recent literature concerning a wide range of processes through which climate change could potentially impact global-scale agricultural productivity, and presents projections of changes in relevant meteorological, hydrological and plant physiological quantities from a climate model ensemble to illustrate key areas of uncertainty.
Abstract: This paper reviews recent literature concerning a wide range of processes through which climate change could potentially impact global-scale agricultural productivity, and presents projections of changes in relevant meteorological, hydrological and plant physiological quantities from a climate model ensemble to illustrate key areas of uncertainty. Few global-scale assessments have been carried out, and these are limited in their ability to capture the uncertainty in climate projections, and omit potentially important aspects such as extreme events and changes in pests and diseases. There is a lack of clarity on how climate change impacts on drought are best quantified from an agricultural perspective, with different metrics giving very different impressions of future risk. The dependence of some regional agriculture on remote rainfall, snowmelt and glaciers adds to the complexity. Indirect impacts via sea-level rise, storms and diseases have not been quantified. Perhaps most seriously, there is high uncertainty in the extent to which the direct effects of CO2 rise on plant physiology will interact with climate change in affecting productivity. At present, the aggregate impacts of climate change on global-scale agricultural productivity cannot be reliably quantified.
828 citations
Cites background from "Integrating pests and pathogens int..."
...This may be through impacts of warming or drought on the resistance of crops to specific diseases and through the increased pathogenicity of organisms by mutation induced by environmental stress (Gregory et al. 2009)....
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References
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01 Mar 2002
Abstract: Over the past 20 years, the term "agro-ecological zones methodology," or AEZ, has become widely used. However, it has been associated with a wide range of different activities that are often related yet quite different in scope and objectives. FAO and IIASA differentiate the AEZ methodology in the following activities:
First, AEZ provides a standardized framework for the characterization of climate, soil, and terrain conditions relevant to agricultural production. In this context, the concepts of "length of growing period" and of latitudinal thermal climates have been applied in mapping activities focusing on zoning at various scales, from the subnational to the global level. Second, AEZ matching procedures are used to identify crop-specific limitations of prevailing climate, soil, and terrain resources, under assumed levels of inputs and management conditions. This part of the AEZ methodology provides estimates of maximum potential and agronomically attainable crop yields for basic land resources units. Third, AEZ provides the frame for various applications. The previous two sets of activities result in very large databases. The information contained in these data sets form the basis for a number of AEZ applications, such as quantification of land productivity, extents of land with rain-fed or irrigated cultivation potential, estimation of land's population supporting capacity, and multi-criteria optimization of the use and development of land resources.
The AEZ methodology uses a land resources inventory to assess, for specified management conditions and levels of inputs, all feasible agricultural land-use options and to quantify anticipated production of cropping activities relevant in the specific agro-ecological context. The characterization of land resources includes components of climate, soils, and land form. The recent availability of digital global databases of climatic parameters, topography, soil and terrain, and land cover ahs allowed for revisions and improvements in calculation procedures. It has also allowed the expansion of assessments of AEZ crop suitability and land productivity potentials to temperate and boreal environments. This effectively enables global coverage for assessments of agricultural potentials.
The AEZ methodologies and procedures have been extended and newly implemented to make use of these digital geographical databases, and to cope with specific characteristics of seasonal temperate and boreal climates. This report describes the methodological adaptations necessary for the global assessment and illustrates with numerous results a wide range of applications.
817 citations
"Integrating pests and pathogens int..." refers background in this paper
...For example, Fischer et al. (2001) modelled the global variation in effects of climate change anticipated in 2050 on potential yields of rainfed cereal crops and demonstrated that cereal-producing regions of Canada, and northern Europe and Russia might be expected to increase production, while many…...
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TL;DR: The links between fundamental knowledge at the plant and plot level and the additional socio-economic variables that determine actual production and trade of food at regional to global scales are critically analyzed.
Abstract: We review recent research of importance to understanding crop and pasture plant species response to climate change. Topics include plant response to elevated CO2 concentration, interactions with climate change variables and air pollutants, impacts of increased climate variability and frequency of extreme events, the role of weeds and pests, disease and animal health, issues in biodiversity, and vulnerability of soil carbon pools. We critically analyze the links between fundamental knowledge at the plant and plot level and the additional socio-economic variables that determine actual production and trade of food at regional to global scales. We conclude by making recommendations for current and future research needs, with a focus on continued and improved integration of experimental and modeling efforts.
732 citations
"Integrating pests and pathogens int..." refers background in this paper
...For the EU as a whole, uninsured losses were estimated at 13 billion Euros for 2003 (Sénat, 2004; Tubiello et al., 2007b)....
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...However, it is widely recognized that these figures are likely to represent an overestimate in actual field and farm level responses because they are derived from experiments and crop models that do not necessarily take limiting factors such as pests and pathogens, competition, nutrient competition, and soil water fully into account (Gregory et al., 1999; Tubiello et al., 2007b)....
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...Estimates of the CO2 fertilization effect vary depending on which experimental approach is used (Long et al., 2006; Tubiello et al., 2007a; Ziska and Bunce, 2007; Ainsworth et al., 2008), but current estimates for increases in crop yield are 10–20% for C3 crops and 0–10% for C4 crops (Ainsworth and…...
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...The increased use of legumes within arable rotations has therefore been of considerable interest (Tubiello et al., 2007b) since legumes can increase N2 fixation in response to elevated CO2 (Soussana and Hartwig, 1996)....
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...The effect of extremes is illustrated by events in the summer of 2003 in parts of Europe, where temperatures were 6 C warmer than long-term means and precipitation deficits of up to 300 mm were recorded (Tubiello et al., 2007b)....
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01 Jan 2005
582 citations
Additional excerpts
...Overall, the results of this and subsequent work demonstrated that climate change would benefit the cereal production of developed countries more than the developing countries, even if cropping practices evolved to allow more than one rainfed crop per year (Fischer et al., 2002, 2005)....
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TL;DR: In this paper, the authors present evidence that mineral nutrient constraints on the fertilizer effect of elevated carbon dioxide can also occur on fertile soil and in the earliest stages of secondary succession, leading to mineral nutrient sequestration by the expanded microflora and a consequent nutritional limitation on plant growth.
Abstract: IN short-term experiments under productive laboratory conditions, native herbaceous plants differ widely in their potential to achieve higher yields at elevated concentrations of atmospheric carbon dioxide1–8. The most responsive species appear to be large fast-growing perennials of recently disturbed fertile soils7,8. These types of plants are currently increasing in abundance9 but it is not known whether this is an effect of rising carbon dioxide or is due to other factors. Doubts concerning the potential of natural vegetation for sustained response to rising carbon dioxide have arisen from experiments on infertile soils, where the stimulus to growth was curtailed by mineral nutrient limitations2,3,10. Here we present evidence that mineral nutrient constraints on the fertilizer effect of elevated carbon dioxide can also occur on fertile soil and in the earliest stages of secondary succession. Our data indicate that there may be a feedback mechanism in which elevated carbon dioxide causes an increase in substrate release into the rhizosphere by non-mycorrhizal plants, leading to mineral nutrient sequestration by the expanded microflora and a consequent nutritional limitation on plant growth.
565 citations
"Integrating pests and pathogens int..." refers background in this paper
...While crop biomass is predicted to increase in response to elevated CO2 concentrations under many circumstances, it is also recognized that crops and soils may subsequently become nutrient limited, especially in terms of nitrogen availability (Diaz et al., 1993)....
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TL;DR: A review of the literature dealing with the relationship between land use change and climate change clearly shows that in recent centuries land-use change has had much greater effects on ecological variables than has climate change as discussed by the authors.
Abstract: Land-use change is related to climate change as both a causal factor and a major way in which the effects of climate change are expressed. As a causal factor, land use influences the flux of mass and energy, and as land-cover patterns change, these fluxes are altered. Projected climate alterations will produce changes in land-cover patterns at a variety of temporal and spatial scales, although human uses of the land are expected to override many effects. A review of the literature dealing with the relationship between land-use change and climate change clearly shows that (1) in recent centuries land-use change has had much greater effects on ecological variables than has climate change; (2) the vast majority of land-use changes have little to do with climate change or even climate; and (3) humans will change land use, and especially land management, to adjust to climate change and these adaptations will have some ecological effects. Therefore, an understanding of the nonclimatic causes of land-use change ...
546 citations
"Integrating pests and pathogens int..." refers background in this paper
...Changes in land use will have many such implications for climate change (Dale, 1997)....
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...Range and severity of a plant disease increased by global warming....
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