SYSTEMLINK - a new project on the effects of stressors across ecosystem barriers

2020 ◽  
Author(s):  
Johanna Girardi ◽  
Ralf Schulz ◽  
Mirco Bundschuh ◽  
Martin H. Entling ◽  
Eva Kröner ◽  
...  
Keyword(s):  
Aquatic Ecosystems ◽  
Multiple Stressors ◽  
Research Training ◽  
Terrestrial Ecosystems ◽  
Water Source ◽  
Training Group ◽  
Landscape Scale ◽  
Top Down ◽  
Bottom Up ◽  
Riparian Plants

<p>The propagation of environmental stressors from water (source) to land (sink) in aquatic-terrestrial meta-ecosystems, has not been intensively investigated. The other way around has been in the focus of linking terrestrial and aquatic domains. To start bridging that gap, SYSTEMLINK, a DFG Research Training Group, addresses the bottom-up and top-down mediated interactions in terrestrial ecosystems, which origin from anthropogenic impairments on aquatic ecosystems. Micropollutants (fungicides and insecticides) as well as invasive species (riparian plants and invertebrates) are considered as crucial forms of multiple stressors in disturbed aquatic ecosystems. SYSTEMLINK will examine the general hypotheses that 1) invasive invertebrates and insecticide exposure and 2) invasive riparian plants and fungicide exposure cause top-down and bottom-up mediated responses in terrestrial ecosystems, respectively. Collaborative experiments in replicated outdoor aquatic-terrestrial mesocosms (site-scale) amended by joint pot experiments (batch-scale), field studies (landscape-scale), and modelling are used to test these general and several more specific hypotheses. The experimental setups will all represent a multi-stress environment and will be derived from the landscape scale. The regular combination of several scales will allow to overcome scale-specific limitations and to ensure both cause-effect quantification and the environmental relevance of the results. Ultimately, SYSTEMLINK thrives to increase our knowledge on effect translation across ecosystem boundaries. By combining biological subsidies and biogeochemical fluxes we will be able to quantify their relative importance. Furthermore, we will closely incorporate the often separated aquatic and terrestrial research areas.</p>

Thematic Section: Conservation Implications of Social-ecological Change in Southern Africa Exploring the alignment between the bottom-up and top-down objectives of a landscape-scale conservation initiative

2021 ◽  
pp. 1-9
Author(s):  
Samantha Mc Culloch-Jones ◽  
Peter Novellie ◽  
Dirk J Roux ◽  
Bianca Currie
Keyword(s):  
Landscape Management ◽  
Landscape Scale ◽  
Ecological Change ◽  
Landscape Conservation ◽  
Top Down ◽  
Bottom Up ◽  
Management Objectives ◽  
Social Ecological ◽  
Trade Offs

Summary Globally, there is a trend towards conserving biodiversity by promoting co-management with multiple stakeholders at landscape scales. Environmental policies emphasize stakeholder engagement in decision-making, yet landscape conservation is typically a bureaucratic–scientific endeavour. Building trusting relationships with stakeholders is key to negotiations that minimize trade-offs and maximize synergies. Incorporating shared stakeholder objectives improves co-management, as they act as incentives for participation and trust development. We explored the degree of alignment between the bottom-up stakeholder objectives and top-down management objectives of a landscape-scale conservation initiative on the West Coast of South Africa. We categorized stakeholders into six affiliations representing governmental, private and community organizations, and using a social-ecological inventory we identified ten shared objectives. Of these objectives, three were shared between all affiliations, namely biodiversity conservation, socioeconomic development and coordination of the landscape approach. The first two aligned with the top-down landscape management objectives and the latter did not. The importance of coordinating landscape approaches in multi-stakeholder landscape-scale initiatives is crucial to long-term success, and we recommend that it be formally included as a landscape management objective. Exploring the alignment between bottom-up and top-down objectives can highlight overlooked functions of co-management and can reduce the transaction costs of sustaining conservation efforts in the long term.

scholarly journals Environmental Pressures on Top-Down and Bottom-Up Forces in Coastal Ecosystems

Diversity ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 444
Author(s):  
Michael J. Blum
Keyword(s):  
Multiple Stressors ◽  
Negative Impact ◽  
Plant Stress ◽  
Coastal Ecosystems ◽  
Freshwater Ecosystems ◽  
Nitrogen Enrichment ◽  
Top Down ◽  
Bottom Up ◽  
Environmental Pressures ◽  
Elevated Salinity

Global change is manifesting new and potent pressures that may determine the relative influence of top-down and bottom-up forces on the productivity of plants that undergird coastal ecosystems. Here, I present a meta-analysis conducted to assess how herbivory, nitrogen enrichment, and elevated salinity influence plant productivity according to the salinity regimes of coastal ecosystems. An examination of 99 studies representing 288 effect sizes across 76 different plant species revealed that elevated salinity negatively affected productivity across all environments, but particularly in freshwater ecosystems. Nitrogen enrichment, on the other hand, positively affected productivity. In agreement with the plant stress hypothesis, herbivory had the greatest negative impact in saline habitats. This trend, however, appears to reverse with nitrogen enrichment, with maximum losses to herbivory occurring in brackish habitats. These findings demonstrate that multiple stressors can yield complex, and sometimes opposite outcomes to those arising from individual stressors. This study also suggests that trophic interactions will likely shift as coastal ecosystems continue to experience nutrient enrichment and sea level rise.

scholarly journals The carbon budget of South Asia

2013 ◽  
Vol 10 (1) ◽  
pp. 513-527 ◽  
Author(s):  
P. K. Patra ◽  
J. G. Canadell ◽  
R. A. Houghton ◽  
S. L. Piao ◽  
N.-H. Oh ◽  
...  
Keyword(s):  
South Asia ◽  
South Asian ◽  
Co2 Flux ◽  
Terrestrial Ecosystems ◽  
Top Down ◽  
Bottom Up ◽  
Ch4 Emissions ◽  
Asian Region ◽  
Co2 Equivalent ◽  
South Asian Region

Abstract. The source and sinks of carbon dioxide (CO2) and methane (CH4) due to anthropogenic and natural biospheric activities were estimated for the South Asian region (Bangladesh, Bhutan, India, Nepal, Pakistan and Sri Lanka). Flux estimates were based on top-down methods that use inversions of atmospheric data, and bottom-up methods that use field observations, satellite data, and terrestrial ecosystem models. Based on atmospheric CO2 inversions, the net biospheric CO2 flux in South Asia (equivalent to the Net Biome Productivity, NBP) was a sink, estimated at −104 ± 150 Tg C yr−1 during 2007–2008. Based on the bottom-up approach, the net biospheric CO2 flux is estimated to be −191 ± 193 Tg C yr−1 during the period of 2000–2009. This last net flux results from the following flux components: (1) the Net Ecosystem Productivity, NEP (net primary production minus heterotrophic respiration) of −220 ± 186 Tg C yr−1 (2) the annual net carbon flux from land-use change of −14 ± 50 Tg C yr−1, which resulted from a sink of −16 Tg C yr−1 due to the establishment of tree plantations and wood harvest, and a source of 2 Tg C yr−1 due to the expansion of croplands; (3) the riverine export flux from terrestrial ecosystems to the coastal oceans of +42.9 Tg C yr−1; and (4) the net CO2 emission due to biomass burning of +44.1 ± 13.7 Tg C yr−1. Including the emissions from the combustion of fossil fuels of 444 Tg C yr−1 for the 2000s, we estimate a net CO2 land–atmosphere flux of 297 Tg C yr−1. In addition to CO2, a fraction of the sequestered carbon in terrestrial ecosystems is released to the atmosphere as CH4. Based on bottom-up and top-down estimates, and chemistry-transport modeling, we estimate that 37 ± 3.7 Tg C yr−1 were released to atmosphere from South Asia during the 2000s. Taking all CO2 and CH4 fluxes together, our best estimate of the net land–atmosphere CO2-equivalent flux is a net source of 334 Tg C yr−1 for the South Asian region during the 2000s. If CH4 emissions are weighted by radiative forcing of molecular CH4, the total CO2-equivalent flux increases to 1148 Tg C yr−1 suggesting there is great potential of reducing CH4 emissions for stabilizing greenhouse gases concentrations.

Bottom-up and top-down approaches to assess multiple stressors over large geographic areas

2000 ◽  
Vol 19 (4) ◽  
pp. 1066-1075 ◽  
Author(s):  
Scott D. Dyer ◽  
Charlotte White-Hull ◽  
Gregory J. Carr ◽  
Eric P. Smith ◽  
Xinhao Wang
Keyword(s):  
Multiple Stressors ◽  
Top Down ◽  
Bottom Up

scholarly journals Bottom-up nutrient and top-down fish impacts on insect-mediated mercury flux from aquatic ecosystems

2013 ◽  
Vol 32 (3) ◽  
pp. 612-618 ◽  
Author(s):  
Taylor A. Jones ◽  
Matthew M. Chumchal ◽  
Ray W. Drenner ◽  
Gabrielle N. Timmins ◽  
Weston H. Nowlin
Keyword(s):  
Aquatic Ecosystems ◽  
Top Down ◽  
Bottom Up ◽  
Mercury Flux

Trophic control of mesopredators in terrestrial ecosystems: top-down or bottom-up?

2007 ◽  
Vol 10 (3) ◽  
pp. 197-206 ◽  
Author(s):  
Bodil Elmhagen ◽  
Stephen P. Rushton
Keyword(s):  
Terrestrial Ecosystems ◽  
Top Down ◽  
Bottom Up

scholarly journals The carbon budget of South Asia

2012 ◽  
Vol 9 (10) ◽  
pp. 13537-13580
Author(s):  
P. K. Patra ◽  
J. G. Canadell ◽  
R. A. Houghton ◽  
S. L. Piao ◽  
N.-H. Oh ◽  
...  
Keyword(s):  
South Asia ◽  
Radiative Forcing ◽  
Net Primary Production ◽  
Co2 Flux ◽  
Terrestrial Ecosystems ◽  
The South ◽  
Top Down ◽  
Bottom Up ◽  
Ch4 Emissions ◽  
Co2 Equivalent

Abstract. The source and sinks of carbon dioxide (CO2) and methane (CH4) due to anthropogenic and natural biospheric activities were estimated for the South Asia region (Bangladesh, Bhutan, India, Nepal, Pakistan and Sri Lanka). Flux estimates were based on top-down methods that use inversions of atmospheric data, and bottom-up methods that use field observations, satellite data, and terrestrial ecosystem models. Based on atmospheric CO2 inversions, the net biospheric CO2 flux in South Asia (equivalent to the Net Biome Productivity, NBP) was a sink, estimated at −104 ± 150 Tg C yr−1 during 2007–2008. Based on the bottom-up approach, the net biospheric CO2 flux is estimated to be −191 ± 193 Tg C yr−1 during the period of 2000–2009. This last net flux results from the following flux components: (1) the Net Ecosystem Productivity, NEP (net primary production minus heterotrophic respiration) of −220 ± 186 Tg C yr−1 (2) the annual net carbon flux from land-use change of −14 ± 50 Tg C yr−1, which resulted from a sink of −16 Tg C yr−1 due to the establishment of tree plantations and wood harvest, and a source of 2 Tg C yr−1 due to the expansion of croplands; (3) the riverine export flux from terrestrial ecosystems to the coastal oceans of +42.9 Tg C yr−1; and (4) the net CO2 emission due to biomass burning of +44.1 ± 13.7 Tg C yr−1. Including the emissions from the combustion of fossil fuels of 444 Tg C yr−1 for the decades of 2000s, we estimate a net CO2 land-to-atmosphere flux of 297 Tg C yr−1. In addition to CO2, a fraction of the sequestered carbon in terrestrial ecosystems is released to the atmosphere as CH4. Based on bottom-up and top-down estimates, and chemistry-transport modeling, we estimate that 37 ± 3.7 Tg C-CH4 yr−1 were released to atmosphere from South Asia during the 2000s. Taking all CO2 and CH4 fluxes together, our best estimate of the net land-to-atmosphere CO2-equivalent flux is a net source of 334 Tg C yr−1 for the South Asia region during the 2000s. If CH4 emissions are weighted by radiative forcing of molecular CH4, the total CO2-equivalent flux increases to 1148 Tg C yr−1 suggesting there is great potential of reducing CH4 emissions for stabilizing greenhouse gases concentrations.

scholarly journals Linking spatial patterns of terrestrial herbivore community structure to trophic interactions

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Jakub Witold Bubnicki ◽  
Marcin Churski ◽  
Krzysztof Schmidt ◽  
Tom A Diserens ◽  
Dries PJ Kuijper
Keyword(s):  
Spatial Distribution ◽  
Community Structure ◽  
Spatial Variation ◽  
Spatial Scales ◽  
Landscape Scale ◽  
Top Down ◽  
Large Herbivores ◽  
Bottom Up ◽  
Vegetation Heterogeneity ◽  
Herbivore Community

Large herbivores influence ecosystem functioning via their effects on vegetation at different spatial scales. It is often overlooked that the spatial distribution of large herbivores results from their responses to interacting top-down and bottom-up ecological gradients that create landscape-scale variation in the structure of the entire community. We studied the complexity of these cascading interactions using high-resolution camera trapping and remote sensing data in the best-preserved European lowland forest, Białowieża Forest, Poland. We showed that the variation in spatial distribution of an entire community of large herbivores is explained by species-specific responses to both environmental bottom-up and biotic top-down factors in combination with human-induced (cascading) effects. We decomposed the spatial variation in herbivore community structure and identified functionally distinct landscape-scale herbivory regimes (‘herbiscapes’), which are predicted to occur in a variety of ecosystems and could be an important mechanism creating spatial variation in herbivory maintaining vegetation heterogeneity.

Towards a quantification of the water planetary boundary

2020 ◽  
Author(s):  
Lan Wang-Erlandsson ◽  
Tom Gleeson ◽  
Fernando Jaramillo ◽  
Samuel C. Zipper ◽  
Dieter Gerten ◽  
...  
Keyword(s):  
Spatial Scales ◽  
Scientific Evidence ◽  
Terrestrial Ecosystems ◽  
Evaluation Framework ◽  
Earth System ◽  
Top Down ◽  
Bottom Up ◽  
Weighting Factors ◽  
The Earth ◽  
The Stability

<p>The planetary boundaries framework defines nine Earth system processes that together demarcate a safe operating space for humanity at the planetary scale. Freshwater - the bloodstream of the biosphere - is an obvious member of the planetary boundary framework.  Water fluxes and stores play a key role for the stability of the Earth’s climate and the world’s aquatic and terrestrial ecosystems. Recent work has proposed to represent the water planetary boundary through six sub-boundaries based on the five primary water stores, i.e., atmospheric water, soil moisture, surface water, groundwater, and frozen water. In order to make it usable on all spatial scales we examine bottom-up and top-down approaches for quantification of the water planetary boundary. For the bottom-up approaches, we explore possible spatially distributed variables defining each of the proposed sub-boundaries, as well as possible weighting factors and keystone regions that can be used for aggregation of the distributed water sub-boundaries to the global scale. For the top-down approaches, we re-examine the stability of key biomes and tipping elements in the Earth System that may be crucially influenced by water cycle modifications. To identify the most appropriate variables for representing the water planetary boundary, we evaluate the range of explored variables with regard to scientific evidence and scientific representation using a hierarchy-based evaluation framework. Finally, we compare the highest ranked top-down and bottom-up approaches in terms of the scientific outcome and implications for governance. In sum, this comprehensive and systematic identification and evaluation of variables, weighting factors, and baseline conditions provides a detailed basis for the future operational quantification of the water planetary boundary. </p>

Psychology and Culture: Top Down Versus Bottom Up?

PsycCRITIQUES ◽  
2005 ◽  
Vol 50 (19) ◽  
Author(s):  
Michael Cole
Keyword(s):  
Top Down ◽  
Bottom Up
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