scholarly journals The Ecosystem Impacts of Severe Warming

2016 ◽  
Vol 106 (5) ◽  
pp. 612-614 ◽  
Author(s):  
Robert Mendelsohn ◽  
Iain C. Prentice ◽  
Oswald Schmitz ◽  
Benjamin Stocker ◽  
Robert Buchkowski ◽  
...  
Keyword(s):  
Boreal Forests ◽  
Animal Species ◽  
Net Primary Productivity ◽  
Forest Biomass ◽  
Terrestrial Ecosystems ◽  
Vegetation Model ◽  
Ecosystem Impacts ◽  
Global Collapse ◽  
Potential Impact ◽  
Nonmarket Services

This paper uses a quantitative dynamic ecosystem vegetation model to explore the potential impact of warming up to 9-12 degrees C on global ecosystems. The paper does not find evidence of a global collapse in terrestrial ecosystems but there is evidence of substantial changes. Temperate and tropical forests expand and replace boreal forests and forests shift to woodlands and parkland at high temperatures. Net primary productivity and standing forest biomass per hectare rise. These changes will affect dependent animal species. Further research is needed to measure the resulting benefits and damages to market and nonmarket services.

Equilibrium analysis of carbon pools and fluxes of forest biomes in the former Soviet Union

1993 ◽  
Vol 23 (1) ◽  
pp. 81-88 ◽  
Author(s):  
Tatyana P. Kolchugina ◽  
Ted S. Vinson
Keyword(s):  
Soviet Union ◽  
Carbon Cycle ◽  
Primary Productivity ◽  
Boreal Forests ◽  
Former Soviet Union ◽  
Net Primary Productivity ◽  
Terrestrial Ecosystems ◽  
Carbon Pool ◽  
Equilibrium Analysis ◽  
Terrestrial Carbon

Natural processes in ocean and terrestrial ecosystems together with human activities have caused a measurable increase in the atmospheric concentration of CO2. It is predicted that an increase in the concentration of CO2 will cause the Earth's temperatures to rise and will accelerate rates of plant respiration and the decay of organic matter, disrupting the equilibrium of the terrestrial carbon cycle. Forests are an important component of the biosphere, and sequestration of carbon in boreal forests may represent one of the few realistic alternatives to ameliorate changes in atmospheric chemistry. The former Soviet Union has the greatest expanse of boreal forests in the world; however, the role of Soviet forests in the terrestrial carbon cycle is not fully understood because the carbon budget of the Soviet forest sector has not been established. In recognition of the need to determine the role of Soviet forests in the global carbon cycle, the carbon budget of forest biomes in the former Soviet Union was assessed based on an equilibrium analysis of carbon cycle pools and fluxes. Net primary productivity was used to identify the rate of carbon turnover in the forest biomes. Net primary productivity was estimated at 4360 Mt of carbon, the vegetation carbon pool was estimated at 110 255 Mt, the litter carbon pool was estimated at 17 525 Mt, and the soil carbon pool was estimated at 319 100 Mt. Net primary productivity of Soviet forest biomes exceeded industrial CO2 emissions in the former Soviet Union by a factor of four and represented approximately 7% of the global terrestrial carbon turnover. Carbon stores in the phytomass and soils of forest biomes of the former Soviet Union represented 16% of the carbon concentrated in the biomass and soils of the world's terrestrial ecosystems. All carbon pools of Soviet forest biomes represented approximately one-seventh of the world's terrestrial carbon pool.

Nutrient Cycling and Energy Flow in Grasslands

2018 ◽  
Author(s):  
Brian J. Wilsey
Keyword(s):  
Energy Flow ◽  
Animal Species ◽  
Net Primary Productivity ◽  
Growing Season ◽  
C4 Plant ◽  
Geographic Scale ◽  
Organic C ◽  
Natural Forms ◽  
Belowground Productivity ◽  
Remote Sensing Techniques

Net primary productivity (NPP) is the amount of C or biomass that accumulates over time and is photosynthesis—autotroph respiration. Annual NPP is estimated by summing positive biomass increments across time periods during the growing season, including offtake to herbivores, which can be high in grasslands. Remote sensing techniques that are used to assess NPP are discussed by the author. Belowground productivity can be high in grasslands, and it is important to carbon storage. Across grasslands on a geographic scale, NPP, N mineralization, and soil organic C all increase with annual precipitation. Within regions, NPP can be strongly affected by the proportion of C4 plant species and animal species composition and diversity. Humans are adding more N to the environment than all the natural forms of addition (fixation and lightning) combined. Animals, especially herbivores, can have strong effects on how plants respond to changes in changes in resource availability.

scholarly journals Dental functional traits of mammals resolve productivity in terrestrial ecosystems past and present

2012 ◽  
Vol 279 (1739) ◽  
pp. 2793-2799 ◽  
Author(s):  
Liping Liu ◽  
Kai Puolamäki ◽  
Jussi T. Eronen ◽  
Majid M. Ataabadi ◽  
Elina Hernesniemi ◽  
...  
Keyword(s):  
Net Primary Productivity ◽  
Terrestrial Ecosystems ◽  
Functional Trait ◽  
Geological Time ◽  
Crown Height ◽  
Short Term ◽  
Functional Interpretation ◽  
Terrestrial Mammals ◽  
Terrestrial Biomes ◽  
The Relationship

We have recently shown that rainfall, one of the main climatic determinants of terrestrial net primary productivity (NPP), can be robustly estimated from mean molar tooth crown height (hypsodonty) of mammalian herbivores. Here, we show that another functional trait of herbivore molar surfaces, longitudinal loph count, can be similarly used to extract reasonable estimates of rainfall but also of temperature, the other main climatic determinant of terrestrial NPP. Together, molar height and the number of longitudinal lophs explain 73 per cent of the global variation in terrestrial NPP today and resolve the main terrestrial biomes in bivariate space. We explain the functional interpretation of the relationships between dental function and climate variables in terms of long- and short-term demands. We also show how the spatially and temporally dense fossil record of terrestrial mammals can be used to investigate the relationship between biodiversity and productivity under changing climates in geological time. The placement of the fossil chronofaunas in biome space suggests that they most probably represent multiple palaeobiomes, at least some of which do not correspond directly to any biomes of today's world.

Using multilevel remote sensing and ground data to estimate forest biomass resources in remote regions: a case study in the boreal forests of interior Alaska

2011 ◽  
Vol 37 (6) ◽  
pp. 596-611 ◽  
Author(s):  
Hans-Erik Andersen ◽  
Jacob Strunk ◽  
Hailemariam Temesgen ◽  
Donald Atwood ◽  
Ken Winterberger
Keyword(s):  
Remote Sensing ◽  
Boreal Forests ◽  
Forest Biomass ◽  
Interior Alaska ◽  
Biomass Resources

scholarly journals The impact of large terrestrial carnivores on Pleistocene ecosystems

2015 ◽  
Vol 113 (4) ◽  
pp. 862-867 ◽  
Author(s):  
Blaire Van Valkenburgh ◽  
Matthew W. Hayward ◽  
William J. Ripple ◽  
Carlo Meloro ◽  
V. Louise Roth
Keyword(s):  
Prey Size ◽  
Habitat Degradation ◽  
Terrestrial Ecosystems ◽  
Growth Data ◽  
Predator Prey ◽  
Body Sizes ◽  
Population Sizes ◽  
Potential Impact ◽  
The Impact ◽  
Ground Sloths

Large mammalian terrestrial herbivores, such as elephants, have dramatic effects on the ecosystems they inhabit and at high population densities their environmental impacts can be devastating. Pleistocene terrestrial ecosystems included a much greater diversity of megaherbivores (e.g., mammoths, mastodons, giant ground sloths) and thus a greater potential for widespread habitat degradation if population sizes were not limited. Nevertheless, based on modern observations, it is generally believed that populations of megaherbivores (>800 kg) are largely immune to the effects of predation and this perception has been extended into the Pleistocene. However, as shown here, the species richness of big carnivores was greater in the Pleistocene and many of them were significantly larger than their modern counterparts. Fossil evidence suggests that interspecific competition among carnivores was relatively intense and reveals that some individuals specialized in consuming megaherbivores. To estimate the potential impact of Pleistocene large carnivores, we use both historic and modern data on predator–prey body mass relationships to predict size ranges of their typical and maximum prey when hunting as individuals and in groups. These prey size ranges are then compared with estimates of juvenile and subadult proboscidean body sizes derived from extant elephant growth data. Young proboscideans at their most vulnerable age fall within the predicted prey size ranges of many of the Pleistocene carnivores. Predation on juveniles can have a greater impact on megaherbivores because of their long interbirth intervals, and consequently, we argue that Pleistocene carnivores had the capacity to, and likely did, limit megaherbivore population sizes.

scholarly journals Changes in carbon fluxes and pools induced by cropland expansion in South and Southeast Asia in the 20th century

2011 ◽  
Vol 8 (6) ◽  
pp. 11979-12012 ◽  
Author(s):  
B. Tao ◽  
H. Tian ◽  
G. Chen ◽  
W. Ren ◽  
C. Lu ◽  
...  
Keyword(s):  
Southeast Asia ◽  
South Asia ◽  
20Th Century ◽  
Forest Biomass ◽  
Terrestrial Ecosystems ◽  
Carbon Fluxes ◽  
Ecosystem Model ◽  
Natural Forests ◽  
Legacy Effect ◽  
South And Southeast Asia

Abstract. A process-based ecosystem model, the Dynamic Land Ecosystem Model (DLEM), was applied to evaluate the effects of cropland expansion on terrestrial carbon fluxes and pools in South and Southeast Asia in the 20th century. The results indicated that cropland expansion in both regions has resulted in a release of 18.26 Pg C into the atmosphere in the study period. Of this amount, approximately 23 % (4.19 Pg C) was released from South Asia and 77 % (14.07 Pg C) from Southeast Asia. More land area was converted to cropland but less carbon was emitted in South Asia than in Southeast Asia, where forest biomass and soil carbon are significantly higher. Carbon losses in vegetation, soil organic matter, and litter carbon pools accounted for 15.09, 2.01, and 1.60 Pg C, respectively. Significant decreases in vegetation carbon occurred across most regions of Southeast Asia due to continuous cropland expansion and depletion of natural forests. Our study also indicated that it is important to take into account the land use legacy effect when evaluating the contemporary carbon balance in terrestrial ecosystems.

Variability of ecosystem carbon source from microbial respiration is controlled by rainfall dynamics

2021 ◽  
Vol 118 (52) ◽  
pp. e2115283118
Author(s):  
Heng Huang ◽  
Salvatore Calabrese ◽  
Ignacio Rodriguez-Iturbe
Keyword(s):  
Primary Productivity ◽  
Microbial Growth ◽  
Net Primary Productivity ◽  
Carbon Sources ◽  
Terrestrial Ecosystems ◽  
Rainfall Regime ◽  
Physical Factors ◽  
Scale Parameters ◽  
Complex Interactions ◽  
Soil Heterotrophic Respiration

Soil heterotrophic respiration (Rh) represents an important component of the terrestrial carbon cycle that affects whether ecosystems function as carbon sources or sinks. Due to the complex interactions between biological and physical factors controlling microbial growth, Rh is uncertain and difficult to predict, limiting our ability to anticipate future climate trajectories. Here we analyze the global FLUXNET 2015 database aided by a probabilistic model of microbial growth to examine the ecosystem-scale dynamics of Rh and identify primary predictors of its variability. We find that the temporal variability in Rh is consistently distributed according to a Gamma distribution, with shape and scale parameters controlled only by rainfall characteristics and vegetation productivity. This distribution originates from the propagation of fast hydrologic fluctuations on the slower biological dynamics of microbial growth and is independent of biome, soil type, and microbial physiology. This finding allows us to readily provide accurate estimates of the mean Rh and its variance, as confirmed by a comparison with an independent global dataset. Our results suggest that future changes in rainfall regime and net primary productivity will significantly alter the dynamics of Rh and the global carbon budget. In regions that are becoming wetter, Rh may increase faster than net primary productivity, thereby reducing the carbon storage capacity of terrestrial ecosystems.

scholarly journals Terrestrial Ecosystem Impacts of Sulfide Mining: Scope of Issues for the Boundary Waters Canoe Area Wilderness, Minnesota, USA

Forests ◽  
2019 ◽  
Vol 10 (9) ◽  
pp. 747 ◽  
Author(s):  
Lee E. Frelich
Keyword(s):  
Boreal Forest ◽  
Large Scale ◽  
Mine Drainage ◽  
Terrestrial Ecosystem ◽  
Terrestrial Ecosystems ◽  
Migration Routes ◽  
Metal Mining ◽  
Mining Operations ◽  
Ecosystem Impacts ◽  
Mining Impacts

Large-scale metal mining operations are planned or underway in many locations across the boreal forest biome in North America, Europe, and Asia. Although many published analyses of mining impacts on water quality in boreal landscapes are available, there is little guidance regarding terrestrial impacts. Scoping of potential impacts of Cu-Ni exploration and mining in sulfide ores are presented for the Boundary Waters Canoe Area Wilderness (BWCAW), Minnesota USA, an area of mostly boreal forest on thin soils and granitic bedrock. Although the primary footprint of the proposed mines would be outside the BWCAW, displacement and fragmentation of forest ecosystems would cause spatial propagation of effects into a secondary footprint within the wilderness. Potential negative impacts include disruption of population dynamics for wildlife species with migration routes, or metapopulations of plant species that span the wilderness boundary, and establishment of invasive species outside the wilderness that could invade the wilderness. Due to linkages between aquatic and terrestrial ecosystems, acid mine drainage can impact lowland forests, which are highly dependent on chemistry of water flowing through them. The expected extremes in precipitation and temperature due to warming climate can also interact with mining impacts to reduce the resilience of forests to disturbance caused by mining.

scholarly journals Biomass losses resulting from insect and disease invasions in US forests

2019 ◽  
Vol 116 (35) ◽  
pp. 17371-17376 ◽  
Author(s):  
Songlin Fei ◽  
Randall S. Morin ◽  
Christopher M. Oswalt ◽  
Andrew M. Liebhold
Keyword(s):  
United States ◽  
Tree Mortality ◽  
Forest Biomass ◽  
The United States ◽  
Ecological Impacts ◽  
Pest Species ◽  
Forest Pests ◽  
Ecosystem Impacts ◽  
Biomass Loss ◽  
Future Loss

Worldwide, forests are increasingly affected by nonnative insects and diseases, some of which cause substantial tree mortality. Forests in the United States have been invaded by a particularly large number (>450) of tree-feeding pest species. While information exists about the ecological impacts of certain pests, region-wide assessments of the composite ecosystem impacts of all species are limited. Here we analyze 92,978 forest plots distributed across the conterminous United States to estimate biomass loss associated with elevated mortality rates caused by the 15 most damaging nonnative forest pests. We find that these species combined caused an additional (i.e., above background levels) tree mortality rate of 5.53 TgC per year. Compensation, in the form of increased growth and recruitment of nonhost species, was not detectable when measured across entire invaded ranges but does occur several decades following pest invasions. In addition, 41.1% of the total live forest biomass in the conterminous United States is at risk of future loss from these 15 pests. These results indicate that forest pest invasions, driven primarily by globalization, represent a huge risk to US forests and have significant impacts on carbon dynamics.

Releases of carbon to the atmosphere from degradation of forests in tropical Asia

1991 ◽  
Vol 21 (1) ◽  
pp. 132-142 ◽  
Author(s):  
R. A. Houghton
Keyword(s):  
Southeast Asia ◽  
Tropical Forest ◽  
Tropical Forests ◽  
Forest Biomass ◽  
Terrestrial Ecosystems ◽  
Tropical Asia ◽  
South And Southeast Asia ◽  
Net Flux ◽  
The Difference ◽  
Annual Flux

The net annual flux of carbon from south and southeast Asia as a result of changes in the area of forests was calculated for the period 1850 to 1985. The total net flux ranged from 14.4 to 24.0 Pg of carbon, depending on the estimates of biomass used in the calculations. High estimates of biomass, based on direct measurement of a few stands, and low estimates of biomass, based on volumes of merchantable wood surveyed over large areas, differ by a factor of almost 2. These and previous estimates of the release of carbon from terrestrial ecosystems to the atmosphere have been based on changes in the area of forests, or rates of deforestation. Recent studies have shown, however, that the loss of carbon from forests in tropical Asia is greater than would be expected on the basis of deforestation alone. This loss of carbon from within forests (degradation) also releases carbon to the atmosphere when the products removed from the forest burn or decay. Thus, degradation should be included in analyses of the net flux of carbon from terrestrial ecosystems. Degradation may also explain some of the difference between estimates of tropical forest biomass if the higher estimates are based on undisturbed forests and the lower estimates are more representative of the region. The implication of degradation for estimates of the release of carbon from terrestrial ecosystems is explored. When degradation was included in the analyses, the net flux of carbon between 1850 and 1985 was 30.2 Pg of carbon, about 25% above that calculated on the basis of deforestation alone (with high estimates of biomass), and about 110% above that calculated with low estimates of biomass. Thus, lower estimates of biomass for contemporary tropical forests do not necessarily result in lower estimates of flux.

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