A role-type model (rope) and its application in assessing climate change impacts on forest landscapes

Gap-phase replacement is a general phenomenon found in forest ecosystems, worldwide. Different tree species can be expected to produce different sizes of gaps when they die. Species also vary in their regeneration success in gaps of different sizes. In this paper, the gap-phase interactions among tree species in a forest stand are simulated by a role-type stand model called ROPE. By incorporation of environmental effects on tree height, ROPE can simulate forest composition and stand leaf area under different climate conditions. The model was developed for forest ecosystems in northeastern China and was used to simulate the forest landscape structures under current climate conditions and under four climate change scenarios for greenhouse gas related warming. These scenarios were obtained from general circulation models developed by different atmospheric research centers. Korean pinebroadleaf mixed forest and larch forest are the major stand types in the study area under present conditions. Under the four climate change scenarios, Korean pine-broadleaf mixed forest would be expected to occur only on the higher parts of large mountains. Larch forest only would be found north of the study area. Broadleaf forest would become the dominant vegetation over the study area. Use of the Kappa statistic to test for similarity in spatial maps, indicates that each climate change scenario would result in a significant change of forest distributions.Supported by The United States National Science Foundation Grant BSR-8702333 to University of Virginia.     

Rainfall variability and Twareg perceptions of climate impacts in Niger

A survey was conducted among the pastoral Twareg of Niger on their perceptions of rainfall impacts for each year from 1947 through 1988. The herders saw drought as a prolonged process with a multi-year onset that culminated in a single year of extreme crisis and abated gradually. The identified crisis years, 1973 and 1984, corresponded with historical rainfall data that showed each of these to have been the second consecutive year of extreme drought. Single years of drought, which may have served as red-flag signals of impending crisis scenarios, were not identified by the herders. Rainfall measurements from the zone of extensive cultivation, south of the pastoral habitat, did not correlate well with key crisis years or the herders' perceptions. Neither did national-level livestock market statistics. It was concluded that rainfall was a reliable indicator for a drought early warning system for the northern Sahel, provided that the measurements were taken from an ecologically-defined pastoral habitat.This paper was written while the author was a research affiliate at the University of Florida Center for African Studies.     

Dual impacts of climate change: forest migration and turnover through life history

Tree species are predicted to track future climate by shifting their geographic distributions, but climate‐mediated migrations are not apparent in a recent continental‐scale analysis. To better understand the mechanisms of a possible migration lag, we analyzed relative recruitment patterns by comparing juvenile and adult tree abundances in climate space. One would expect relative recruitment to be higher in cold and dry climates as a result of tree migration with juveniles located further poleward than adults. Alternatively, relative recruitment could be higher in warm and wet climates as a result of higher tree population turnover with increased temperature and precipitation. Using the USDA Forest Service's Forest Inventory and Analysis data at regional scales, we jointly modeled juvenile and adult abundance distributions for 65 tree species in climate space of the eastern United States. We directly compared the optimal climate conditions for juveniles and adults, identified the climates where each species has high relative recruitment, and synthesized relative recruitment patterns across species. Results suggest that for 77% and 83% of the tree species, juveniles have higher optimal temperature and optimal precipitation, respectively, than adults. Across species, the relative recruitment pattern is dominated by relatively more abundant juveniles than adults in warm and wet climates. These different abundance‐climate responses through life history are consistent with faster population turnover and inconsistent with the geographic trend of large‐scale tree migration. Taken together, this juvenile–adult analysis suggests that tree species might respond to climate change by having faster turnover as dynamics accelerate with longer growing seasons and higher temperatures, before there is evidence of poleward migration at biogeographic scales.     

'Changing climate, changing health, changing stories' profile: using an EcoHealth approach to explore impacts of climate change on inuit health

Global climate change and its impact on public health exemplify the challenge of managing complexity and uncertainty in health research. The Canadian North is currently experiencing dramatic shifts in climate, resulting in environmental changes which impact Inuit livelihoods, cultural practices, and health. For researchers investigating potential climate change impacts on Inuit health, it has become clear that comprehensive and meaningful research outcomes depend on taking a systemic and transdisciplinary approach that engages local citizens in project design, data collection, and analysis. While it is increasingly recognised that using approaches that embrace complexity is a necessity in public health, mobilizing such approaches from theory into practice can be challenging. In 2009, the Rigolet Inuit Community Government in Rigolet, Nunatsiavut, Canada partnered with a transdisciplinary team of researchers, health practitioners, and community storytelling facilitators to create the Changing Climate, Changing Health, Changing Stories project, aimed at developing a multi-media participatory, community-run methodological strategy to gather locally appropriate and meaningful data to explore climate-health relationships. The goal of this profile paper is to describe how an EcoHealth approach guided by principles of transdisciplinarity, community participation, and social equity was used to plan and implement this climate-health research project. An overview of the project, including project development, research methods, project outcomes to date, and challenges encountered, is presented. Though introduced in this one case study, the processes, methods, and lessons learned are broadly applicable to researchers and communities interested in implementing EcoHealth approaches in community-based research.     

Net climate impacts of forest biomass production and utilization in managed boreal forests

In this work, we studied the potentials offered by managed boreal forests and forestry to mitigate the climate change using forest‐based materials and energy in substituting fossil‐based materials (concrete and plastic) and energy (coal and oil). For this purpose, we calculated the net climate impacts (radiative forcing) of forest biomass production and utilization in the managed Finnish boreal forests (60°–70°N) over a 90‐year period based on integrated use forest ecosystem model simulations (on carbon sequestration and biomass production of forests) and life‐cycle assessment (LCA) tool. When studying the effects of management on the radiative forcing in a system integrating the carbon sink/sources dynamics in both biosystem and technosystem, the current forest management (baseline management) was used a reference management. Our results showed that the use of forest‐based materials and energy in substituting fossil‐based materials and energy would provide an effective option for mitigating climate change. The negative climate impacts could be further decreased by maintaining forest stocking higher over the rotation compared to the baseline management and by harvesting stumps and coarse roots in addition to logging residues in the final felling. However, the climate impacts varied substantially over time depending on the prevailing forest structure and biomass assortment (timber, energy biomass) used in substitution.     

Multiple stressors,nonlinear effects and the implications of climate change impacts on marine coastal ecosystems

Global climate change will undoubtedly be a pressure on coastal marine ecosystems, affecting not only species distributions and physiology but also ecosystem functioning. In the coastal zone, the environmental variables that may drive ecological responses to climate change include temperature, wave energy, upwelling events and freshwater inputs, and all act and interact at a variety of spatial and temporal scales. To date, we have a poor understanding of how climate‐related environmental changes may affect coastal marine ecosystems or which environmental variables are likely to produce priority effects. Here we use time series data (17 years) of coastal benthic macrofauna to investigate responses to a range of climate‐influenced variables including sea‐surface temperature, southern oscillation indices (SOI, Z4), wind‐wave exposure, freshwater inputs and rainfall. We investigate responses from the abundances of individual species to abundances of functional traits and test whether species that are near the edge of their tolerance to another stressor (in this case sedimentation) may exhibit stronger responses. The responses we observed were all nonlinear and some exhibited thresholds. While temperature was most frequently an important predictor, wave exposure and ENSO‐related variables were also frequently important and most ecological variables responded to interactions between environmental variables. There were also indications that species sensitive to another stressor responded more strongly to weaker climate‐related environmental change at the stressed site than the unstressed site. The observed interactions between climate variables, effects on key species or functional traits, and synergistic effects of additional anthropogenic stressors have important implications for understanding and predicting the ecological consequences of climate change to coastal ecosystems.     

Benefits of polyphenols on gut microbiota and implications in human health

The biological properties of dietary polyphenols are greatly dependent on their bioavailability that, in turn, is largely influenced by their degree of polymerization. The gut microbiota play a key role in modulating the production, bioavailability and, thus, the biological activities of phenolic metabolites, particularly after the intake of food containing high-molecular-weight polyphenols. In addition, evidence is emerging on the activity of dietary polyphenols on the modulation of the colonic microbial population composition or activity. However, although the great range of health-promoting activities of dietary polyphenols has been widely investigated, their effect on the modulation of the gut ecology and the two-way relationship “polyphenols ? microbiota” are still poorly understood.Only a few studies have examined the impact of dietary polyphenols on the human gut microbiota, and most were focused on single polyphenol molecules and selected bacterial populations. This review focuses on the reciprocal interactions between the gut microbiota and polyphenols, the mechanisms of action and the consequences of these interactions on human health.     

Biological invasions in the Antarctic: extent, impacts and implications

Alien microbes, fungi, plants and animals occur on most of the sub-Antarctic islands and some parts of the Antarctic continent. These have arrived over approximately the last two centuries, coincident with human activity in the region. Introduction routes have varied, but are largely associated with movement of people and cargo in connection with industrial, national scientific program and tourist operations. The large majority of aliens are European in origin. They have both direct and indirect impacts on the functioning of species-poor Antarctic ecosystems, in particular including substantial loss of local biodiversity and changes to ecosystem processes. With rapid climate change occurring in some parts of Antarctica, elevated numbers of introductions and enhanced success of colonization by aliens are likely, with consequent increases in impacts on ecosystems. Mitigation measures that will substantially reduce the risk of introductions to Antarctica and the sub-Antarctic must focus on reducing propagule loads on humans, and their food, cargo, and transport vessels.     

Ecological implications of projected climate change scenarios in forest ecosystems in northern Michigan,USA

Changes in seasonal temperature and precipitation, as predicted by several global climate models, were utilized together with a stochastic daily weather stimulation model to evaluate the ecological impacts of projected global climate change scenarios on temperate forest ecosystems in northern Michigan, USA. The model simulated the impacts of these projected changes on ecologically significant weather variables, such as the length of the frost-free period, average growing season temperature, average growing season degree days (4.4° C basis), summer precipitation, potential evaporation during the growing season, and the ratio of precipitation to potential evaporation during July and August. The results indicate that even the lower range of predicted climate changes could lead to ecologically and commercially significant changes in the composition and productivity of these forests. Of particular concern is the possibility of climatically induced regional decline episodes for a number of important commercial species in the northern temperate forests of central North America.     

The implications of improved communications for participatory forest management in Tanzania

Following the 1998 National Forest Policy and Forest Act of 2002, participatory forest management (PFM) is being introduced in Tanzania. PFM has two key objectives: to reduce forest degradation thereby increasing ecosystem services, and to improve the livelihoods of local villagers. A unique data set collected in 2006 suggests that significant challenges remain with respect to communicating the new forest policies if the objectives of PFM are to be achieved. First, villagers as a group are much less well informed than other stakeholders, and their knowledge is often inaccurate. Second, women are less likely than men to have heard of the changes. Third, how PFM will contribute to poverty reduction (a key objective of PFM) is not always clear. Fourth, environmental degradation may not be reduced as much as anticipated – without alternatives sources, villagers often continue to cut trees for charcoal and firewood in the protected forests. Finally, several mismatches in perceptions are identified that could lead to difficulties in implementing PFM.     

Temperate forest termites: ecology,biogeography, and ecosystem impacts

1. Wood decomposition in temperate forests is dominated by termites, fungi, and some species of ants and beetles. Outside of urban areas, temperate termite ecology is largely unknown, particularly when compared to tropical termites and other temperate organisms in the functional guild of wood‐decomposing animals. 2. This review combines climate habitat modelling with knowledge of species physiology, behaviour, and community interactions to identify and prioritise future research on temperate termite ecology and biogeography. 3. Using a correlative climate model, the regional distributions of three common temperate forest termite species are shown to correlate with different aspects of climate (e.g. mean versus minimum monthly temperature), but that overall their distributions within temperate systems correlate more strongly with temperature variables than with precipitation variables. 4. Existing data are synthesised to outline how the subterranean, wood‐nesting behaviour of most temperate forest termite species links their activity to an additional set of non‐climate controls: wood type and tree species, soil depth, fungal activity, ant abundances and phenology, and competitive asymmetries among termite species. 5. Although fine‐scale estimates of temperate termite abundances are rare, we provide upper bounds on their ecosystem impacts and illustrate how their regional abundances may influence forest structure and habitat availability for other organisms. 6. This review highlights that rigorous ecological studies in non‐urban, intact ecosystems – with a particular focus on community interactions – are critically needed to accurately project future abundances, economic impacts, and ecosystem effects of temperate forest termites.     

Long-term records of coral calcification across the central Great Barrier Reef: assessing the impacts of river runoff and climate change

Calcification rates are reported for 41 long-lived Porites corals from 7 reefs, in an inshore to offshore transect across the central Great Barrier Reef (GBR). Over multi-decadal timescales, corals in the mid-shelf (1947–2008) and outer reef (1952–2004) regions of the GBR exhibit a significant increase in calcification of 10.9 ± 1.1 % (1.4 ± 0.2 % per decade; ±1 SE) and 11.1 ± 3.9 % (2.1 ± 0.8 % per decade), respectively, while inner-shelf (1930–2008), reefs show a decline of 4.6 ± 1.3 % (0.6 ± 0.2 % per decade). This long-term decline in calcification for the inner GBR is attributed to the persistent ongoing effects of high sediment/nutrients loads from wet season river discharges, compounded by the effects of thermal stress, especially during the 1998 bleaching event. For the recent period (1990–2008), our data show recovery from the 1998 bleaching event, with no significant trend in the rates of calcification (1.1 ± 2.0 %) for the inner reefs, while corals from the mid-shelf central GBR show a decline of 3.3 ± 0.9 %. These results are in marked contrast to the extreme reef-wide declines of 14.2 % reported by De’ath et al. (2009) for the period of 1990–2005. The De’ath et al. (2009) results are, however, found to be compromised by the inclusion of incomplete final years, duplicated records, together with a bias toward inshore reefs strongly affected by the 1998 bleaching. Our new findings nevertheless continue to raise concerns, with the inner-shelf reefs continuing to show long-term declines in calcification consistent with increased disturbance from land-based effects. In contrast, the more ‘pristine’ mid- and outer-shelf reefs appear to be undergoing a transition from increasing to decreasing rates of calcification, possibly reflecting the effects of CO₂-driven climate change. Our study highlights the importance of properly undertaken, regular assessments of coral calcification that are representative of the distinctive cross-shelf environments and discriminate between local disturbances and the global impacts of climate change and ocean acidification.     

Modelling potential impacts of climate change on the spatial distribution of zonal forest communities in Switzerland

Abstract. A spatially explicit, climate-sensitive vegetation model is presented to simulate both present and future distribution of potential natural vegetation types in Switzerland at the level of zonal forest communities. The model has two versions: (1) a ‘basic’ version using geographical region, aspect, bedrock (represented by soil pH), and elevation, and (2) a ‘climate-sensitive’ version obtained by replacing elevation (complex environmental gradient) with temperature (climatic factor). Version 2 is used to predict vegetation response under different (today's and projected) climatic conditions. Two regional climate scenarios are applied: (1) assuming an annual mean temperature increase of 1.1 — 1.4 °C, and (2) assuming an increase of 2.2 — 2.75 °C. Both scenarios result in significant changes of the spatial vegetation patterns as compared with today's climatic conditions. In scenario 1, ca. 33 % of the sample points remain unchanged in terms of the simulated zonal forest community; in scenario 2, virtually all sample points change. The most noticeable changes occur on the Swiss Plateau with Carpinion forests (zonal vegetation of present colline belt) expanding to areas that are occupied today by submontane and low-montane Fagus forests. To estimate the reliability of the simulation, quantitative (comparison with field mapping) and qualitative (comparison with climate types in the Alpine region) tests are performed and the main limitations of the approach are evaluated.     

Long-term fire frequency variability in the eastern Canadian boreal forest: the influences of climate vs. local factors

The influence of climatic and local nonclimatic factors on the fire regime of the eastern Canadian boreal forest over the last 8000 years is investigated by examining charred particles preserved in four lacustrine deposits. Herein, we compare the distribution of fire-free intervals (FFIs) and the synchronicity of fire events among sites, using Ripley's K -function to determine the extent of the role of local-scale vs. large-scale processes with respect to fire control. Between 8000 and 5800 cal. bp (calibrated years before present) the climatic and ecological conditions were less conducive to fire events than after this date. After 5800 cal. bp , the number of fires per 1000 years (fire frequency) progressively increased, reaching a maximum ca. 3400 cal. bp . There was a sharp decrease in fire frequency during the last 800 years. Between 8000 and 4000 cal. bp , comparable FFIs and synchronous fire episodes were determined for the study sites. During this period, the fire frequency was predominantly controlled by climate. After 4000 cal. bp , two sites displayed independent fire histories (different FFI distributions or asynchronous fire events), underlining the important influence of local factors, including short-term fuel wetness, characteristics of the watershed and landscape connectivity, in determining fire occurrence. We conclude that climatic changes occurred during the last 4000 years that induced a rise in the water table; this may explain the high spatial heterogeneity in fire history. Current and projected global climatic changes may cause similar spatial variability in fire frequency.     

Biodiversity as a solution to mitigate climate change impacts on the functioning of forest ecosystems

Forest ecosystems are critical to mitigating greenhouse gas emissions through carbon sequestration. However, climate change has affected forest ecosystem functioning in both negative and positive ways, and has led to shifts in species/functional diversity and losses in plant species diversity which may impair the positive effects of diversity on ecosystem functioning. Biodiversity may mitigate climate change impacts on (I) biodiversity itself, as more‐diverse systems could be more resilient to climate change impacts, and (II) ecosystem functioning through the positive relationship between diversity and ecosystem functioning. By surveying the literature, we examined how climate change has affected forest ecosystem functioning and plant diversity. Based on the biodiversity effects on ecosystem functioning (B→EF), we specifically address the potential for biodiversity to mitigate climate change impacts on forest ecosystem functioning. For this purpose, we formulate a concept whereby biodiversity may reduce the negative impacts or enhance the positive impacts of climate change on ecosystem functioning. Further B→EF studies on climate change in natural forests are encouraged to elucidate how biodiversity might influence ecosystem functioning. This may be achieved through the detailed scrutiny of large spatial/long temporal scale data sets, such as long‐term forest inventories. Forest management strategies based on B→EF have strong potential for augmenting the effectiveness of the roles of forests in the mitigation of climate change impacts on ecosystem functioning.     

Designing a sustainable monitoring framework for assessing impacts of climate change at Joshua Tree National Park,USA

Predicting species’ responses to a warming and drying (for North America’s desert southwest region) climate provides focus for monitoring to track shifts in species’ occupancy, and ultimately identifying management options to stem losses to biodiversity. Here we describe a monitoring framework to achieve that objective. A first step is to identify which species to monitor; which species will provide the greatest information for discerning the effects of climate change versus the myriad of other stressors that may impact their distributions and abundance. To select focal species we employed two complimentary approaches. One tool, vulnerability assessments (VAs), use available scientific literature to assess exposure to environmental stressors and adaptive capacity or resilience to climate change. Another approach is habitat suitability modeling (HSM) coupled with simulated temperature shifts. This method statistically combines environmental variables at known species’ locations, such as climate and terrain, to model the complex interaction of factors that constrain a species’ distribution. All other variables held constant, simulated temperature shifts can identify species’ sensitivities to those shifts and identify potential refugia. We used these tools to assess risk of local extinction due to predicted levels of climate change, as well as to identify where to locate monitoring plots to best capture the shifts in species distributions over time. A challenge in developing a monitoring program to document the effects of climate change on biodiversity is program sustainability. One way to support and enhance the sustainability of such a program will be to couple trained biologists with volunteer citizen scientists.     

Habitat-specific responses in the flowering phenology and seed set of alpine plants to climate variation: implications for global-change impacts

The timing of the snowmelt is a crucial factor in determining the phenological schedule of alpine plants. A long-term monitoring of snowmelt regimes in a Japanese alpine area revealed that the onset of the snowmelt season has been accelerated during the last 17 years in early snowmelt sites but that such a trend has not been detected in late snowmelt sites. This indicates that the global warming effect on the snowmelt pattern may be site-specific. The flowering phenology of fellfield plants in an exposed wind-blown habitat was consistent between an unusually warm year (1998) and a normal year (2001). In contrast, the flowering occurrence of snowbed plants varied greatly between the years depending on the snowmelt time. There was a large number of flowering species in the fellfield community from mid- to late to late June and from mid- to late July. The flowering peak of an early-melt snowbed plant community was in the middle of the flowering season and that of a late-melt snowbed community was in the early flowering season. These habitat-specific phenological patterns were consistent between 1998 and 2001. The effects of the variation in flowering timing on seed-set success were evaluated for an entomophilous snowbed herb, Peucedanum multivittatum, along the snowmelt gradient during a 5-year period. When flowering occurred prior to early August, mean temperature during the flowering season positively influenced the seed set. When flowering occurred later than early August, however, the plants enjoyed high seed-set success irrespective of temperature conditions if frost damage was absent. These observations are probably explained based on the availability of pollinators, which depends not only on ambient temperature but also on seasonal progress. These results suggest that the effects of climate change on biological interaction may vary depending on the specific habitat in the alpine ecosystem in which diverse snowmelt patterns create complicated seasonality for plants within a very localized area.