Impact of Elevated Atmospheric CO2 on Biodiversity: Mechanistic Population-Dynamic Perspective

1993 ◽  
Vol 41 (1) ◽  
pp. 11 ◽  
Author(s):  
HP Possingham
Keyword(s):  
Climate Change ◽  
Environmental Change ◽  
Elevated Co2 ◽  
Physical Environment ◽  
Keystone Species ◽  
Direct Interaction ◽  
Terrestrial Ecosystems ◽  
Minor Role ◽  
Elevated Atmospheric Co2 ◽  
The Impact

Biodiversity is characteristically defined on three levels: genetic diversity, species diversity and ecosystem diversity. In this paper I consider the impact of elevated CO2 and associated climate change on the biodiversity of terrestrial systems at the species level. I attempt to understand the impact of a rapidly changing physical environment mechanistically. The direct impact of elevated CO2 is emphasised. A changing physical environment will cause behavioural and physiological responses in organisms that will affect population dynamics and interspecific relationships. In the short term, extinctions will occur via the direct interaction of species with their changing environment. Species exposed to new diseases, and species dependent on mutualists or keystone species that become extinct or change geographical range, may become extinct rapidly through interactions with other species. I hypothesise that the effect of environmental change on competitive interactions will play a minor role in causing declines in biodiversity. Existing literature on the impact of climate change on terrestrial ecosystems emphasises the way in which ecosystems and species should track suitable climates across the landscape. Here I argue that each species will be affected in one, or a combination, of the following ways: range change to track shifting climate zones, tolerating the environmental change, microevolutionary change, and extinction.

Climate-forced changes of bio-productivity of Belorussian terrestrial ecosystems

2019 ◽  
pp. 77-88
Author(s):  
S. A. Lysenko
Keyword(s):  
Climate Change ◽  
Carbon Dioxide ◽  
Vegetation Index ◽  
Precipitation Amount ◽  
Terrestrial Ecosystems ◽  
Vegetation Period ◽  
Climatic Trend ◽  
Vegetation Growth ◽  
Current Century ◽  
The Impact

The spatial and temporal particularities of Normalized Differential Vegetation Index (NDVI) changes over territory of Belarus in the current century and their relationship with climate change were investigated. The rise of NDVI is observed at approximately 84% of the Belarus area. The statistically significant growth of NDVI has exhibited at nearly 35% of the studied area (t-test at 95% confidence interval), which are mainly forests and undeveloped areas. Croplands vegetation index is largely descending. The main factor of croplands bio-productivity interannual variability is precipitation amount in vegetation period. This factor determines more than 60% of the croplands NDVI dispersion. The long-term changes of NDVI could be explained by combination of two factors: photosynthesis intensifying action of carbon dioxide and vegetation growth suppressing action of air warming with almost unchanged precipitation amount. If the observed climatic trend continues the croplands bio-productivity in many Belarus regions could be decreased at more than 20% in comparison with 2000 year. The impact of climate change on the bio-productivity of undeveloped lands is only slightly noticed on the background of its growth in conditions of rising level of carbon dioxide in the atmosphere.

scholarly journals Climate change and agroecosystems: the effect of elevated atmospheric CO2 and temperature on crop growth, development, and yield

2005 ◽  
Vol 35 (3) ◽  
pp. 730-740 ◽  
Author(s):  
Nereu Augusto Streck
Keyword(s):  
Climate Change ◽  
Crop Yield ◽  
Co2 Concentration ◽  
Crop Growth ◽  
Atmospheric Co2 ◽  
C3 Plants ◽  
Elevated Atmospheric Co2 ◽  
Growth Development ◽  
Carbon Dioxide Co2 ◽  
The Impact

The amount of carbon dioxide (CO2) of the Earth´s atmosphere is increasing, which has the potential of increasing greenhouse effect and air temperature in the future. Plants respond to environment CO2 and temperature. Therefore, climate change may affect agriculture. The purpose of this paper was to review the literature about the impact of a possible increase in atmospheric CO2 concentration and temperature on crop growth, development, and yield. Increasing CO2 concentration increases crop yield once the substrate for photosynthesis and the gradient of CO2 concentration between atmosphere and leaf increase. C3 plants will benefit more than C4 plants at elevated CO2. However, if global warming will take place, an increase in temperature may offset the benefits of increasing CO2 on crop yield.

scholarly journals Decomposition analysis on soybean productivity increase under elevated CO2 using 3-D canopy model reveals synergestic effects of CO2 and light in photosynthesis

2019 ◽  
Vol 126 (4) ◽  
pp. 601-614 ◽  
Author(s):  
Qingfeng Song ◽  
Venkatraman Srinivasan ◽  
Steve P Long ◽  
Xin-Guang Zhu
Keyword(s):  
Climate Change ◽  
Elevated Co2 ◽  
Developmental Stages ◽  
Decomposition Analysis ◽  
Crop Productivity ◽  
Minor Role ◽  
Co2 Uptake ◽  
Canopy Architecture ◽  
Area Index ◽  
Canopy Model

Abstract Background and Aims Understanding how climate change influences crop productivity helps in identifying new options to increase crop productivity. Soybean is the most important dicotyledonous seed crop in terms of planting area. Although the impacts of elevated atmospheric [CO2] on soybean physiology, growth and biomass accumulation have been studied extensively, the contribution of different factors to changes in season-long whole crop photosynthetic CO2 uptake [gross primary productivity (GPP)] under elevated [CO2] have not been fully quantified. Methods A 3-D canopy model combining canopy 3-D architecture, ray tracing and leaf photosynthesis was built to: (1) study the impacts of elevated [CO2] on soybean GPP across a whole growing season; (2) dissect the contribution of different factors to changes in GPP; and (3) determine the extent, if any, of synergism between [CO2] and light on changes in GPP. The model was parameterized from measurements of leaf physiology and canopy architectural parameters at the soybean Free Air CO2 Enrichment (SoyFACE) facility in Champaign, Illinois. Key Results Using this model, we showed that both a CO2 fertilization effect and changes in canopy architecture contributed to the large increase in GPP while acclimation in photosynthetic physiological parameters to elevated [CO2] and altered leaf temperature played only a minor role in the changes in GPP. Furthermore, at early developmental stages, elevated [CO2] increased leaf area index which led to increased canopy light absorption and canopy photosynthesis. At later developmental stages, on days with high ambient light levels, the proportion of leaves in a canopy limited by Rubisco carboxylation increased from 12.2 % to 35.6 %, which led to a greater enhancement of elevated [CO2] to GPP. Conclusions This study develops a new method to dissect the contribution of different factors to responses of crops under climate change. We showed that there is a synergestic effect of CO2 and light on crop growth under elevated CO2 conditions.

Environmental Peacebuilding

2020 ◽  
Author(s):  
Tobias Ide
Keyword(s):  
Climate Change ◽  
Environmental Change ◽  
Natural Resources ◽  
Physical Violence ◽  
Environmental Issues ◽  
Environmental Problems ◽  
Worst Case ◽  
Post Conflict ◽  
Entry Points ◽  
The Impact

Interest in the environmental dimensions of peacebuilding has emerged from the early 2000s onward due to two developments. First, with an increasing number of peacebuilding interventions by the international community and nongovernmental organizations (NGOs), addressing environmental issues in post-conflict contexts has become a major concern. This is especially so as water and land are crucial for (re-)building livelihoods while modern wars produce considerable environmental damage. Second, an increasing number of scholars and policymakers are expressing concerns about the security implications of global environmental change, with the impact of climate change on violent conflict being a particularly salient topic. A focus on environmental cooperation and its potential peace-enhancing effects provides a complementary analytical perspective that can counter determinist and securitizing environmental conflict narratives. Environmental peacebuilding can be broadly defined as efforts to build more peaceful relations through conflict prevention, resolution, and recovery processes that integrate the management of environmental issues. In this context, peace refers to negative peace (the absence of physical violence) as well as positive peace (the absence of structural violence and the inconceivability of physical violence). Environmental peacebuilding can take place at the macro level (e.g., between states) as well as on the meso level and the micro level (e.g., between or within local communities). Environmental peacebuilding includes four sets of practices (which are not mutually exclusive): First, with resources like water or land becoming increasingly scarce in some regions and oil or mining projects often being heavily contested, preventing conflicts over natural resources is increasingly important. Second, in post-conflict contexts, natural resources must be managed well, for instance to reduce land-related grievances or prevent conflict financing through resource revenues. Third, climate change mitigation, adaptation to environmental change, and disaster risk reduction (DRR) can reduce grievances and promote community coherence. Finally, joint and severe environmental problems can act as entry points for cooperation across political divides, hence supporting processes of trust building and deepening interdependence (the respective set of practices is often termed environmental peacemaking). These practices can also fail, however, implying that they have no impact on environmental problems or peace processes. In the worst case, environmental peacebuilding practices can even facilitate new forms of exclusion, conflict, and environmental degradation. Over the past two decades, interest in environmental peacebuilding has grown remarkably, not at least due to the intensification of environmental problems and recent trends toward a less peaceful world. As a result of these developments, the literature on environmental peacebuilding has grown dramatically.

The European Ecotron of Montpellier: experimental platforms to study ecosystem response to climate change

2020 ◽  
Author(s):  
Joana Sauze ◽  
Jacques Roy ◽  
Clément Piel ◽  
Damien Landais ◽  
Emmanuel S Gritti ◽  
...  
Keyword(s):  
Climate Change ◽  
Ecosystem Functioning ◽  
Soil Depth ◽  
Land Use Changes ◽  
Terrestrial Ecosystems ◽  
Experimental Unit ◽  
Natural Ecosystems ◽  
Ecological Processes ◽  
Canopy Area ◽  
The Impact

<p>The sustainability of agricultural, forested and other managed or natural ecosystems is critical for the future of mankind. However, the services provided by these ecosystems are under threat due to climate change, loss of biodiversity, and land use changes. In order to face the challenges of preserving or improving ecosystems services and securing food supply we need to understand and forecast how ecosystems will respond to current and future changes. To help answer those questions Ecotrons facilities are born. Such infrastructures provide sets of confinement units for the manipulation of environmental conditions and real-time measurement of ecological processes under controlled and reproduceable conditions, bridging the gap between the complexity of in natura studies and the simplicity of laboratory experiments.</p><p>The European Ecotron of Montpellier (www.ecotron.cnrs.fr) is an experimental research infrastructure for the study of the impact of climate change on ecosystem functioning and biodiversity. This infrastructure offers, through calls open to the international community, three experimental platforms at different scales. The Macrocosms platform is composed of twelve 40 m<sup>3</sup> units, each able to host 2-12 t lysimeters, with a 2-5 m² canopy area and a soil depth of up to 2 m. The Mesocosms one has eighteen 2-4 m<sup>3</sup> units, each able to host lysimeters of 0.4-1 m depth and 0.4-1 m² area. The Microcosms platform consists of growth chambers (1 m height, 1 m² area) in which smaller units (with photosynthetic plants, soils, insects, etc.) can be installed. Each experimental unit of each platform allows to confine terrestrial ecosystems. This way, environmental parameters such as temperature (-10 to +50 °C), relative humidity (20-80 %), precipitation (sprinkler or drip) and atmospheric CO<sub>2</sub> concentration (200-1000 ppm) are strictly and continuously controlled and recorded. But the uniqueness of the European Ecotron of Montpellier lies on its ability to also continuously measure, in each unit, net gas exchange (evapotranspiration, CO<sub>2</sub> / CH<sub>4</sub> / N<sub>2</sub>O net fluxes) that occur in between the ecosystem studied and the atmosphere, as well as CO<sub>2</sub>, H<sub>2</sub>O, N<sub>2</sub>O and O<sub>2</sub> isotopologues. Those tools are powerful and remarkable to access additional information about processus involved in ecosystem functioning.</p><p>The aim of this presentation is to describe the Macrocosms and the Mesocosms platforms through examples of international projects recently run in these platforms.</p>

Minirhizotron imaging reveals that nodulation of field-grown soybean is enhanced by free-air CO2 enrichment only when combined with drought stress

2013 ◽  
Vol 40 (2) ◽  
pp. 137 ◽  
Author(s):  
Sharon B. Gray ◽  
Reid S. Strellner ◽  
Kannan K. Puthuval ◽  
Christopher Ng ◽  
Ross E. Shulman ◽  
...  
Keyword(s):  
Environmental Change ◽  
Elevated Co2 ◽  
N2 Fixation ◽  
Root Length ◽  
Nitrogen Concentration ◽  
Global Environmental Change ◽  
Leguminous Plant ◽  
Root Production ◽  
Elevated Atmospheric Co2 ◽  
Global Environmental

The rate of N2 fixation by a leguminous plant is a product of the activity of individual nodules and the number of nodules. Initiation of new nodules and N2 fixation per nodule are highly sensitive to environmental conditions. However, the effects of global environmental change on nodulation in the field are largely unknown. It is also unclear whether legumes regulate nodulation in response to environment solely by varying root production or also by varying nodule density per unit of root length. This study utilised minirhizotron imaging as a novel in situ method for assessing the number, size and distribution of nodules in field-grown soybean (Glycine max (L.) Merr.) exposed to elevated atmospheric CO2 ([CO2]) and reduced precipitation. We found that nodule numbers were 134–229% greater in soybeans grown at elevated [CO2] in combination with reduced precipitation, and this response was driven by greater nodule density per unit of root length. The benefits of additional nodules were probably offset by an unfavourable distribution of nodules in shallow, dry soil in reduced precipitation treatment under elevated [CO2] but not ambient [CO2]. In fact, significant decreases in seed and leaf nitrogen concentration also occurred only in elevated [CO2] with reduced precipitation. This study demonstrates the potential of minirhizotron imaging to reveal previously uncharacterised changes in nodule production and distribution in response to global environmental change.

scholarly journals Positive feedback of elevated CO<sub>2</sub> on soil respiration in late autumn and winter

2014 ◽  
Vol 11 (6) ◽  
pp. 8749-8787 ◽  
Author(s):  
L. Keidel ◽  
C. Kammann ◽  
L. Grünhage ◽  
G. Moser ◽  
C. Müller
Keyword(s):  
Soil Respiration ◽  
Elevated Co2 ◽  
Management Practices ◽  
Co2 Enrichment ◽  
Terrestrial Ecosystems ◽  
Winter Period ◽  
Elevated Atmospheric Co2 ◽  
Late Autumn ◽  
Below Ground ◽  
Autumn And Winter

Abstract. Soil respiration of terrestrial ecosystems, a major component in the global carbon cycle is affected by elevated atmospheric CO2 concentrations. However, seasonal differences of feedback effects of elevated CO2 have rarely been studied. At the Giessen Free-Air CO2 Enrichment (GiFACE) site, the effects of +20% above ambient CO2 concentration (corresponds to conditions reached 2035–2045) have been investigated since 1998 in a temperate grassland ecosystem. We defined five distinct annual periods, with respect to management practices and phenological cycles. For a period of three years (2008–2010), weekly measurements of soil respiration were carried out with a survey chamber on vegetation-free subplots. The results revealed a pronounced and repeated increase of soil respiration during late autumn and winter dormancy. Increased CO2 losses during the autumn period (September–October) were 15.7% higher and during the winter period (November–March) were 17.4% higher compared to respiration from control plots. However, during spring time and summer, which are characterized by strong above- and below-ground plant growth, no significant change in soil respiration was observed at the FACE site under elevated CO2. This suggests (i) that soil respiration measurements, carried out only during the vegetative growth period under elevated CO2 may underestimate the true soil-respiratory CO2 loss (i.e. overestimate the C sequestered) and (ii) that additional C assimilated by plants during the growing period and transferred below-ground will quickly be lost via enhanced heterotrophic respiration outside the main vegetation period.

scholarly journals Response of water balance components to climate change in permanent grassland soil ecosystems

2021 ◽  
Author(s):  
Veronika Forstner ◽  
Jannis Groh ◽  
Matevz Vremec ◽  
Markus Herndl ◽  
Harry Vereecken ◽  
...  
Keyword(s):  
Climate Change ◽  
Elevated Temperature ◽  
Water Balance ◽  
Elevated Co2 ◽  
Climatic Conditions ◽  
Seepage Water ◽  
Grassland Ecosystem ◽  
Water Balance Components ◽  
Atmospheric Co2 Concentrations ◽  
The Impact

Abstract. Hydrological processes are affected by changing climatic conditions. In grassland areas, changes in the ecosystem water balance components will alter aboveground biomass production (AGB), which in turn is of great importance for ecological and economic benefits of grassland. However, the effects of climate change on the ecosystem productivity and water fluxes are often derived from climate change experiments. It is still largely unknown whether and how the experimental approach itself affects the results of such studies. The aim of this investigation was to identify the effects of climate change on the water balance and the productivity of grassland ecosystems by comparing results of two contrasting approaches of climate change experiments. The first (manipulative) climate change approach uses increased atmospheric CO2 concentrations and surface temperatures. The second (observational) approach uses data from a space-for-time substitution approach along a gradient in climatic conditions. The climate change effects on the ecosystem’s water balance was determined by using high-precision weighable monolithically lysimeters at each site over a period of four years, including the exceptionally dry year 2018. The aridity index, defined as the grass-reference evapotranspiration (ET0) to precipitation (P), was used to characterize the hydrological status of the regime (i.e. energy- or water limited system). The observational approach (grassland ecosystem moved to a drier and warmer site), resulted in a large decrease of precipitation (P) and non-rainfall water (NRW), an increase in actual evapotranspiration (ETa) and upward directed water fluxes from deeper soil and hence a decline of seepage water as well a decrease in AGB and water use efficiency (WUE). The manipulative approach (grassland ecosystem treated in place) resulted in decreasing P and NRW under conditions of elevated temperature but responded with increasing NRW for elevated CO2 as compared to the reference. Similarly, an elevated CO2 and heating increased the ecosystem’s water loss by ETa. However, the effect of increasing CO2 on ETa was largely compensated by the opposite effect of an elevated temperature in the combined treatment. The seepage water rate also increased with elevated CO2, whereas it clearly decreased for the heating treatment as compared to the reference. All treatments led to a reduction of the grassland productivity in terms of the AGB and to reduced WUE as compared to the grassland ecosystem under reference conditions. The consideration of changes in NRW and P by the treatments needs to be considered in climate change experiments to avoid an over- (elevated temperature) or underestimation (elevated CO2) of the effects of climate change on ecosystems response, especially for sites where water limitation plays a role. The impact of drought periods on seepage rates (potentially leading to groundwater recharge) was more pronounced for the relatively humid site with a longer ETa period without water stress than for a relatively dry site. The hydroclimatological and ecohydrological indicators were similarly affected by changes in temperature, atmospheric CO2 concentrations, and precipitation in both manipulative and observational climate change experiments except for the responses of ETa and AGB in the dry and warm year 2018. The resulting response differences between the two climate change approaches were explained by the actual soil moisture status. The results suggest that energy limited ecosystems tend to increase their ETa and AGB production (excluding effects from elevated CO2 and temperature), but water limited ecosystems respond with a decrease in ETa as a result of water stress, which leads to a clear decline of AGB. The results also suggest that climate change experiments should account for the possible change of the hydrological status of the ecosystem and impose sufficiently extreme levels of climatic conditions within their set-up to allow such changes to occur for capturing the full response of the ecosystem. The results may help to better understanding the impact of climate change on future ecosystem functioning.

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