scholarly journals Ambient and experimental warming effects on an alpine bryophyte community

2021 ◽  
Author(s):  
Kristel van Zuijlen ◽  
Johan Asplund ◽  
Snorre Sundsbø ◽  
Oda Sofie Dahle ◽  
Kari Klanderud
Keyword(s):  
Climate Change ◽  
Functional Group ◽  
Positive Response ◽  
Individual Species ◽  
Experimental Warming ◽  
Dryas Octopetala ◽  
Pleurocarpous Mosses ◽  
Species Specific ◽  
Over Time

Alpine and arctic bryophytes have been found to respond negatively to climate change, but since they are often analysed as one functional group, there is limited knowledge on species-specific responses. In this study, we examine how nearly two decades of experimental warming by open top chambers (OTC) and ambient warming have affected the bryophyte community structure in an alpine Dryas octopetala heath in Finse, southwest Norway. In contrast to what we expected, we found that bryophyte abundance, species richness and evenness increased over time in the control plots, indicating a positive response to ambient warming. However, the increase in bryophyte abundance and cover was suppressed in experimentally warmed plots compared to control plots. Bryophyte community composition changed in a similar direction in response to both ambient and experimental warming. Acrocarpous mosses were not affected stronger by warming than pleurocarpous mosses, but individual species and taxa showed contrasting responses. Our study highlights the importance of studying bryophyte responses to environmental change, as well as combining long-term observations with experimental warming.

scholarly journals Modeling the Effects of Global Change on Ecosystem Processes in a Tropical Rainforest

Forests ◽  
2020 ◽  
Vol 11 (2) ◽  
pp. 213
Author(s):  
Ann E. Russell ◽  
William J. Parton
Keyword(s):  
Climate Change ◽  
Tree Species ◽  
Functional Group ◽  
Plant Traits ◽  
Biogeochemical Cycles ◽  
Individual Species ◽  
Soil Processes ◽  
Individual Tree ◽  
Forest Biogeochemistry

Research Highlights: Ongoing land-use change and climate change in wet tropical forests can potentially drive shifts in tree species composition, representing a change in individual species within a functional group, tropical evergreen trees. The impacts on the global carbon cycle are potentially large, but unclear. We explored the differential effects of species within this functional group, in comparison with the effects of climate change, using the Century model as a research tool. Simulating effects of individual tree species on biome-level biogeochemical cycles constituted a novel application for Century. Background and Objectives: A unique, long-term, replicated field experiment containing five evergreen tree species in monodominant stands under similar environmental conditions in a Costa Rican wet forest provided data for model evaluation. Our objectives were to gain insights about this forest’s biogeochemical cycles and effects of tree species within this functional group, in comparison with climate change. Materials and Methods: We calibrated Century, using long-term meteorological, soil, and plant data from the field-based experiment. In modeling experiments, we evaluated effects on forest biogeochemistry of eight plant traits that were both observed and modeled. Climate-change simulation experiments represented two climate-change aspects observed in this region. Results: Model calibration revealed that unmodeled soil processes would be required to sustain observed P budgets. In species-traits experiments, three separate plant traits (leaf death rate, leaf C:N, and allocation to fine roots) resulted in modeled biomass C stock changes of >50%, compared with a maximum 21% change in the climate-change experiments. Conclusions: Modeled ecosystem properties and processes in Century were sensitive to changes in plant traits and nutrient limitations to productivity. Realistic model output was attainable for some species, but unusual plant traits thwarted predictions for one species. Including more plant traits and soil processes could increase realism, but less-complex models provide an accessible means for exploring plant-soil-atmosphere interactions.

scholarly journals Ant-mediated seed dispersal in a warmed world

2013 ◽  
Author(s):  
Katharine L. Stuble ◽  
Courtney M. Patterson ◽  
Mariano A. Rodriguez-Cabal ◽  
Relena R. Ribbons ◽  
Robert R. Dunn ◽  
...  
Keyword(s):  
Climate Change ◽  
Seed Dispersal ◽  
Interspecific Interactions ◽  
Forest Site ◽  
Activity Levels ◽  
Seed Removal ◽  
Experimental Warming ◽  
Climatic Warming ◽  
Plant Seed ◽  
Species Specific

Climate change affects communities both directly and indirectly via changes in interspecific interactions. One such interaction that may be altered under climate change is the ant-plant seed dispersal mutualism common in deciduous forests of the eastern US. As climatic warming alters the abundance and activity levels of ants, the potential exists for shifts in rates of ant-mediated seed removal. We used an experimental temperature manipulation at two sites in the eastern US (Harvard Forest in Massachusetts and Duke Forest in North Carolina) to examine the potential impacts of climatic warming on overall rates of seed dispersal (using Asarum canadense seeds) as well as species-specific rates of seed dispersal at the Duke Forest site. We also examined the relationship between ant critical thermal maxima (CTmax) and the mean seed removal temperature for each ant species. We found that seed removal rates did not change as a result of experimental warming at either study site, nor were there any changes in species-specific rates of seed dispersal. There was, however, a positive relationship between CTmax and mean seed removal temperature, whereby species with higher CTmax removed more seeds at hotter temperatures. The temperature at which seeds were removed was influenced by experimental warming as well as diurnal and day-to-day fluctuations in temperature. Taken together, our results suggest that while temperature may play a role in regulating seed removal by ants, ant plant seed-dispersal mutualisms may be more robust to climate change than currently assumed.

Ancient sedimentary DNA reveals long-term impact of climate change on northern flora

2020 ◽  
Author(s):  
Inger Alsos ◽  
Keyword(s):  
Climate Change ◽  
Sediment Cores ◽  
Time Lag ◽  
Individual Species ◽  
Long Distance ◽  
Site Specific ◽  
Polar Urals ◽  
Rapid Responses ◽  
Long Term Impact

<p>Arctic and alpine species are disproportionally affected by climate change, and knowledge about their ability to survive or disperse is essential for their long-term conservation. Ancient sedimentary DNA (sedaDNA) has improved as a proxy for reconstructing past floras, and may now be applied in high throughput analyses. Our lab has analysed, or is in the process of analysing, sedaDNA from ~40 long (up to 26 000 years old) and 11 short (0-1000 years old) lake sediment cores from the Europe (Alps, Norway, Svalbard, Iceland, Polar Urals). Both general and site-specific patterns have emerged from these data. For example, the taxa recorded in sedaDNA often indicate a warmer climate than that which has been inferred based on pollen records; this is in concordance with macrofossil evidence. Also, the limits of past northern tree lines may have been underestimated based on pollen studies. Some heathland species, such as Vaccinium spp. and Empetrum, often show a time lag in arrival compared with other species with similar climatic requirements. Thus, despite the fact that they have berries and therefore are well adapted to long-distance dispersal by birds, our data show they are constrained from rapid responses to climate changes. Other patterns are site-specific. For example, we see a stepwise doubling of floristic richness from the Last Glacial Maximum to the Holocene in the Polar Urals, which is barely detectable in the pollen analyses. Further, the majority of taxa with a mainly arctic-alpine distributions survived the early-Holocene climate warming, when shrub and trees entered the region, probably due to a very heterogeneous landscape that allows co-existence of species with different requirements. In contrast, arctic-alpine taxa disappear from the catchment a subset of the lakes studied in North Norway after shrub and forest expansion. Linking this type of information to characteristics of these biogeographic regions may provide useful when planning for future nature reserves. In the near future, the combination of many sites, complete DNA reference libraries, and emerging molecular methods will allow for the tracking of individual species through time and space.</p>

scholarly journals A Review of Factors to Consider for Permanent Cordon Establishment and Maintenance

Agronomy ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1811
Author(s):  
Patrick O’Brien ◽  
Roberta De Bei ◽  
Mark Sosnowski ◽  
Cassandra Collins
Keyword(s):  
Climate Change ◽  
Heat Stress ◽  
Vascular System ◽  
Vascular Diseases ◽  
Stress Conditions ◽  
Normal Flow ◽  
Training Techniques ◽  
Long Term Consequences ◽  
Over Time

Decisions made during the establishment and reworking of permanent cordon arms may have long-term consequences on vineyard health and longevity. This review aims to summarise several of the important considerations that must be taken into account during cordon establishment and maintenance. Commonly practiced cordon training techniques such as wrapping developing arms tightly around the cordon wire may result in a constriction of the vascular system, becoming worse over time and disrupting the normal flow of water and nutrients. Studies have shown that other factors of cordon decline such as the onset of vascular diseases may be influenced by pre-existing stress conditions. Such conditions could be further exacerbated by water and heat stress events, an important consideration as these scenarios become more common under the influence of climate change. Vineyard sustainability may be improved by adopting cordon training techniques which promote long-term vitality and avoid a reduction in vine defence response and the costly, premature reworking of vines.

scholarly journals Bryophyte cover and richness decline after 18 years of experimental warming in Alpine Sweden

2019 ◽  
Author(s):  
Juha Alatalo ◽  
Annika Jägerbrand ◽  
Mohammad Bagher Erfanian ◽  
Shengbin Chen ◽  
Shou-Qin Sun ◽  
...  
Keyword(s):  
Climate Change ◽  
Negative Impact ◽  
Species Abundance ◽  
Experimental Warming ◽  
Litter Cover ◽  
General Decline ◽  
Principal Response Curve ◽  
Heath Community ◽  
Abundance And Diversity

Background and Aims: Climate change is expected to affect alpine and Arctic tundra communities. Most previous long-term studies have focused on impacts on vascular plants, but this study examined potential impacts of long-term warming on bryophyte communities.Methods: Experimental warming with open-top chambers (OTCs) was applied for 18 years to a mesic meadow and a dry heath alpine plant community. Species abundance was measured in 1995, 1999, 2001 and 2013. Key results: Species composition changed significantly from the original communities in the heath, but remained similar in the mesic meadow. Experimental warming increased beta diversity in the heath community. Bryophyte cover and species richness both declined with long-term warming, while Simpson diversity showed no significant responses. Over the 18-year period, bryophyte cover in warmed plots decreased from 43% to 11% in heath and from 68% to 35% in meadow (75% and 48% decline, respectively, in original cover), while richness declined by 39% and 26%, respectively. The decline in both cover and richness first emerged after seven years. Warming caused a significant increase in litter in both plant communities. Litter cover had a negative impact on bryophyte cover in both communities. Conclusions: This study showed that bryophyte species do not all respond similarly to climate change. Total bryophyte cover declined in both dry heath and mesic meadow communities under experimental long-term warming (by 1.5-3°C), driven by general declines in many species. Principal response curve, cover and richness results suggested that bryophytes in alpine heath vegetation are more susceptible to warming than those in meadow vegetation, supporting the suggestion that bryophyte communities may be less resistant in drier environments than in wetter habitats. Species loss was slower than the general decline in bryophyte abundance, and diversity remained similar in both communities. Increased litter cover led to a steep decline in bryophyte cover.

scholarly journals Ant-mediated seed dispersal in a warmed world

2013 ◽  
Author(s):  
Katharine L. Stuble ◽  
Courtney M. Patterson ◽  
Mariano A. Rodriguez-Cabal ◽  
Relena R. Ribbons ◽  
Robert R. Dunn ◽  
...  
Keyword(s):  
Climate Change ◽  
Seed Dispersal ◽  
Interspecific Interactions ◽  
Forest Site ◽  
Activity Levels ◽  
Seed Removal ◽  
Experimental Warming ◽  
Climatic Warming ◽  
Plant Seed ◽  
Species Specific

Climate change affects communities both directly and indirectly via changes in interspecific interactions. One such interaction that may be altered under climate change is the ant-plant seed dispersal mutualism common in deciduous forests of the eastern US. As climatic warming alters the abundance and activity levels of ants, the potential exists for shifts in rates of ant-mediated seed removal. We used an experimental temperature manipulation at two sites in the eastern US (Harvard Forest in Massachusetts and Duke Forest in North Carolina) to examine the potential impacts of climatic warming on overall rates of seed dispersal (using Asarum canadense seeds) as well as species-specific rates of seed dispersal at the Duke Forest site. We also examined the relationship between ant critical thermal maxima (CTmax) and the mean seed removal temperature for each ant species. We found that seed removal rates did not change as a result of experimental warming at either study site, nor were there any changes in species-specific rates of seed dispersal. There was, however, a positive relationship between CTmax and mean seed removal temperature, whereby species with higher CTmax removed more seeds at hotter temperatures. The temperature at which seeds were removed was influenced by experimental warming as well as diurnal and day-to-day fluctuations in temperature. Taken together, our results suggest that while temperature may play a role in regulating seed removal by ants, ant plant seed-dispersal mutualisms may be more robust to climate change than currently assumed.

scholarly journals Leaf Multi-Element Network Reveals the Change of Species Dominance Under Nitrogen Deposition

2021 ◽  
Vol 12 ◽  
Author(s):  
Jiahui Zhang ◽  
Tingting Ren ◽  
Junjie Yang ◽  
Li Xu ◽  
Mingxu Li ◽  
...  
Keyword(s):  
Climate Change ◽  
Global Climate Change ◽  
Global Climate ◽  
N Deposition ◽  
High Plasticity ◽  
Species Dominance ◽  
Novel Approach ◽  
Novel Concept ◽  
Species Specific

Elements are important functional traits reflecting plant response to climate change. Multiple elements work jointly in plant physiology. Although a large number of studies have focused on the variation and allocation of multiple elements in plants, it remains unclear how these elements co-vary to adapt to environmental change. We proposed a novel concept of the multi-element network including the mutual effects between element concentrations to more effectively explore the alterations in response to long-term nitrogen (N) deposition. Leaf multi-element networks were constructed with 18 elements (i.e., six macronutrients, six micronutrients, and six trace elements) in this study. Multi-element networks were species-specific, being effectively discriminated irrespective of N deposition level. Different sensitive elements and interactions to N addition were found in different species, mainly concentrating on N, Ca, Mg, Mn, Li, Sr, Ba, and their related stoichiometry. Interestingly, high plasticity of multi-element network increased or maintained relative aboveground biomass (species dominance) in community under simulated N deposition, which developed the multi-element network hypothesis. In summary, multi-element networks provide a novel approach for exploring the adaptation strategies of plants and to better predict the change of species dominance under altering nutrient availability or environmental stress associated with future global climate change.

scholarly journals Review of science-based assessments of species vulnerability: Contributions to decision-making for assisted migration

2011 ◽  
Vol 87 (06) ◽  
pp. 745-754 ◽  
Author(s):  
Tannis Beardmore ◽  
Richard Winder
Keyword(s):  
Climate Change ◽  
Forest Tree ◽  
Individual Species ◽  
Assisted Migration ◽  
Forest Species ◽  
Genetic Risk Assessment ◽  
Change Models ◽  
Forest Management Planning ◽  
Species Vulnerability ◽  
Species Specific

Assessing climate change impacts on forest species can significantly assist forest management planning. Recently, many tools have been developed for assessing species-specific vulnerability to climate change. These tools are question-based assessments that consider multiple criteria for individual species; the criteria are related to exposure and sensitivity to climate change. The following tools are discussed in relation to their use in Canada: (1) the NatureServe Climate Change Vulnerability Index; (2) the System for Assessing Vulnerability of Species to Climate Change (SAVS); (3) the Forest Tree Genetic Risk Assessment; (4) the Index for Predicting Tree Species Vulnerability; (5) ecological standards developed for the assisted migration of Torreya taxifolia; and (6) the Seeds of Success Program. These tools can all be applied to different forest species and they vary in such areas as their species-specific evaluation criteria, means for addressing uncertainty, and the integration of climate change models.

Implementing Long-Term Climate Policy: Time Inconsistency, Domestic Politics, International Anarchy

2009 ◽  
Vol 9 (3) ◽  
pp. 20-39 ◽  
Author(s):  
Jon Hovi ◽  
Detlef F. Sprinz ◽  
Arild Underdal
Keyword(s):  
Climate Change ◽  
Climate Policy ◽  
Domestic Politics ◽  
Time Inconsistency ◽  
Considerable Uncertainty ◽  
Policy Problem ◽  
Effective Policy ◽  
Commitment Problems ◽  
Over Time

As a quintessential long-term policy problem, climate change poses two major challenges. The first is to develop, under considerable uncertainty, a plan for allocating resources over time to achieve an effective policy response. The second is to implement this plan, once arrived at, consistently over time. We consider the second of these two challenges, arguing that it consists of three interrelated, commitment problems—the time inconsistency problem, the domestic politics problem, and the anarchy problem. We discuss each of these commitment problems in some detail, explore how they relate to climate policy, and suggest institutional designs that may help limit their adverse impact. While each of these commitment problems is difficult to tackle on its own, climate change requires us to cope with all of them at once. This is likely one major reason why we have so far made only modest headway on this vital issue.

scholarly journals Alternative carbon price trajectories can avoid excessive carbon removal

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Jessica Strefler ◽  
Elmar Kriegler ◽  
Nico Bauer ◽  
Gunnar Luderer ◽  
Robert C. Pietzcker ◽  
...  
Keyword(s):  
Climate Change ◽  
Climate Change Mitigation ◽  
Carbon Budget ◽  
Carbon Price ◽  
Carbon Neutrality ◽  
In The Beginning ◽  
Carbon Prices ◽  
Change Mitigation ◽  
Over Time

AbstractThe large majority of climate change mitigation scenarios that hold warming below 2 °C show high deployment of carbon dioxide removal (CDR), resulting in a peak-and-decline behavior in global temperature. This is driven by the assumption of an exponentially increasing carbon price trajectory which is perceived to be economically optimal for meeting a carbon budget. However, this optimality relies on the assumption that a finite carbon budget associated with a temperature target is filled up steadily over time. The availability of net carbon removals invalidates this assumption and therefore a different carbon price trajectory should be chosen. We show how the optimal carbon price path for remaining well below 2 °C limits CDR demand and analyze requirements for constructing alternatives, which may be easier to implement in reality. We show that warming can be held at well below 2 °C at much lower long-term economic effort and lower CDR deployment and therefore lower risks if carbon prices are high enough in the beginning to ensure target compliance, but increase at a lower rate after carbon neutrality has been reached.

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