Landscape Partnership Resources Library
CLIMATE’S SMOKY SPECTRE
With their focus on greenhouse gases, atmospheric scientists have largely overlooked lowly soot particles. But black carbon is now a hot topic among researchers and politicians.
El Nino in a changing climate
El Nino events, characterized by anomalous warming in the eastern equatorial Pacific Ocean, have global climatic teleconnections and are the most dominant feature of cyclic climate variability on subdecadal timescales. Understanding changes in the frequency or characteristics of El Nino events in a changing climate is therefore of broad scientific and socioeconomic interest. Recent studies (1–5) show that the canonical El Nino has become less frequent and that a different kind of El Nino has become more common during the late twentieth century, in which warm sea surface temperatures (SSTs) in the central Pacific are flanked on the east and west by cooler SSTs. This type of El Nino, termed the central Pacific El Nino (CP-El Nino; also termed the dateline El Nino (2), El Nino Modoki (3) or a warm pool El Nino (5), differs from the canonical eastern Pacific El Nino (EP-El Nino) in both the location of maximum SST anomalies and tropical–midlatitude teleconnections. Here we show changes in the ratio of CP-El Nino to EP-El Nino under projected global EQ warming scenarios from the Coupled Model Intercomparison Project phase 3 multi-model data set (6). Using calculations based 10o S on historical El Nino indices, we find that projections of anthropogenic climate change are associated with an increased frequency of the CP-El Nino compared to the EP-El Nino. When restricted to the six climate models with the best representation of the twentieth-century ratio of CP-El Nino to EP-El Nino, the occurrence ratio of CP-El Nino/EP-El Nino is projected to increase as 10o N much as five times under global warming. The change is related to a flattening of the thermocline in the equatorial Pacific.
A safe operating space for humanity
Identifying and quantifying planetary boundaries that must not be transgressed could help prevent human activities from causing unacceptable environmental change, argue Johan RockstrÖm and colleagues.
Call for a climate culture shift
A new book describes the rapid reshaping of human priorities needed to save the planet from global warming. Some of that change is already under way at the community level, explains Robert Costanza.
Carbon respiration from subsurface peat accelerated by climate warming in the subarctic
Among the largest uncertainties in current projections of future climate is the feedback between the terrestrial carbon cycle and climate1. Northern peatlands contain one-third of the world’s soil organic carbon, equivalent to more than half the amount of carbon in the atmosphere2. Climate-warming-induced acceleration of carbon dioxide (CO2) emissions through enhanced respiration of thick peat deposits, centuries to millennia old, may form a strong positive carbon cycle–climate feedback. The long-term temperature sensitivity of carbon in peatlands, especially at depth, remains uncertain, however, because of the short duration or correlative nature of field studies3–5 and the disturbance associated with respiration measurements below the surface in situ or during laboratory incubations6,7. Here we combine non-disturbing in situ measurements of CO2 respiration rates and isotopic (13C) composition of respired CO2 in two whole-ecosystem climate- manipulation experiments in a subarctic peatland. We show that approximately 1 6C warming accelerated total ecosystem respira- tion rates on average by 60% in spring and by 52% in summer and that this effect was sustained for at least eight years. While warm- ing stimulated both short-term (plant-related) and longer-term (peat soil-related) carbon respiration processes, we find that at least 69% of the increase in respiration rate originated from carbon in peat towards the bottom (25–50 cm) of the active layer above the permafrost. Climate warming therefore accelerates respiration of the extensive, subsurface carbon reservoirs in peat- lands to a much larger extent than was previously thought6,7. Assuming that our data from a single site are indicative of the direct response to warming of northern peatland soils on a global scale, we estimate that climate warming of about 1 6C over the next few decades could induce a global increase in heterotrophic respiration of 38–100 megatonnes of C per year. Our findings suggest a large, long-lasting, positive feedback of carbon stored in northern peatlands to the global climate system.
A BURDEN BEYOND BEARING
The climate situation may be even worse than you think. In the first of three features, Richard Monastersky looks at evidence that keeping carbon dioxide beneath dangerous levels is tougher than previously thought.
Carbon in idle croplands
The collapse of the Soviet Union had diverse consequences, not least the abandonment of crop cultivation in many areas. One result has been the vast accumulation of soil organic carbon in the areas affected.
Attributing physical and biological impacts to anthropogenic climate change
Significant changes in physical and biological systems are occurring on all continents and in most oceans, with a concentration of available data in Europe and North America. Most of these changes are in the direction expected with warming temperature. Here we show that these changes in natural systems since at least 1970 are occurring in regions of observed temperature increases, and that these temperature increases at continental scales cannot be explained by natural climate variations alone. Given the conclusions from the Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report that most of the observed increase in global average temperatures since the mid-twentieth century is very likely to be due to the observed increase in anthropogenic greenhouse gas concentrations, and furthermore that it is likely that there has been significant anthropogenic warming over the past 50 years averaged over each continent except Antarctica, we conclude that anthropogenic climate change is having a significant impact on physical and biological systems globally and in some continents.
Biodiversity and ecosystem multifunctionality
Biodiversity loss can affect ecosystem functions and services1–4. Individual ecosystem functions generally show a positive asymptotic relationship with increasing biodiversity, suggesting that some species are redundant5–8. However, ecosystems are managed and conserved for multiple functions, which may require greater biodiversity. Here we present an analysis of published data from grassland biodiversity experiments9–11, and show that ecosystem multifunctionality does require greater numbers of species. We analysed each ecosystem function alone to identify species with desirable effects. We then calculated the number of species with positive effects for all possible combinations of functions. Our results show appreciable differences in the sets of species influ- encing different ecosystem functions, with average proportional overlap of about 0.2 to 0.5. Consequently, as more ecosystem pro- cesses were included in our analysis, more species were found to affect overall functioning. Specifically, for all of the analysed experiments, there was a positive saturating relationship between the number of ecosystem processes considered and the number of species influencing overall functioning. We conclude that because different species often influence different functions, studies focus- ing on individual processes in isolation will underestimate levels of biodiversity required to maintain multifunctional ecosystems.
Decision Analysis for Climate Change (Online) – ALC3196 Class Agenda
January 15 ‐ March 17th, 2015. Total Contact Time: 28‐34 hours
Ecosystems Vulnerability Datasets
Table displaying name, dataset link, topic name, topic categories, comments/links, and list of tags.
The use of large wood in stream restoration: experiences from 50 projects in Germany and Austria
1. Wood is increasingly used in restoration projects to improve the hydromorphological and ecological status of streams and rivers. However, despite their growing importance, only a few of these projects are described in the open literature. To aid practitioners, we conducted a postal mail survey to summarize the experiences gained in central Europe and compile data on 50 projects. 2. Our results indicated the potential for improvement from an ecological point of view, as the number and total wood volume, and the median volume of single wood structures placed in the streams per project, were low compared with the potential natural state. Moreover, many wood structures were placed nearly parallel to the water flow, reducing their beneficial effect on stream hydraulics and morphology. 3. Restoration success has been monitored in only 58% of the projects. General con- clusions drawn include the following. (i) The potential effects of wood placement must be evaluated within a watershed and reach-scale context. (ii) Wood measures are most successful if they mimic natural wood. (iii) Effects of wood structures on stream morphology are strongly dependent on conditions such as stream size and hydrology. (iv) Wood placement has positive effects on several fish species. (v) Most projects revealed a rapid improvement of the hydromorphological status. 4. Most of the wood structures have been fixed, called ‘hard engineering’. However, soft engineering methods (use of non-fixed wood structures) are known to result in more natural channel features for individual stream types, sizes and sites, and are significantly more cost-effective. 5. Synthesis and applications. Large wood has been used successfully in several projects in central Europe, predominantly to increase the general structural complexity using fixed wood structures. Our results recommend the use of less costly soft engineering techniques (non-fixed wood structures), higher amounts of wood, larger wood struc- tures and improved monitoring programmes for future restoration projects comparable with those in this study. We recommend the use of ‘passive restoration’ methods (restor- ing the process of wood recruitment on large scales) rather than ‘active restoration’ (placement of wood structures on a reach scale), as passive restoration avoids the risk of non-natural amounts or diversity of wood loading developing within streams. Local, active placement of wood structures must be considered as an interim measure until passive restoration methods have increased recruitment sufficiently. Key-words: alpine streams, lowland streams, monitoring, mountain streams, passive restoration, restoration success, soft-engineering, woody debris
The floodplain large-wood cycle hypothesis: A mechanism for the physical and biotic structuring of temperate forested alluvial valleys in the North Pacific coastal ecoregion
A ‘floodplain large-wood cycle’ is hypothesized as a mechanism for generating landforms and influencing river dynamics in ways that structure and maintain riparian and aquatic ecosystems of forested alluvial river valleys of the Pacific coastal temperate rainforest of North America. In the cycle, pieces of wood large enough to resist fluvial transport and remain in river channels initiate and stabilize wood jams, which in turn create alluvial patches and protect them from erosion. These stable patches provide sites for trees to ma- ture over hundreds of years in river valleys where the average cycle of floodplain turnover is much briefer, thus providing a future source of large wood and reinforcing the cycle. Different tree species can function in the floodplain large-wood cycle in different ecological regions, in different river valleys within regions, and within individual river valleys in which forest composition changes through time. The cycle promotes a physically complex, biodiverse, and self-reinforcing state. Conversely, loss of large trees from the system drives landforms and ecosystems toward an alternate stable state of diminished biogeomorphic complexity. Reestablishing large trees is thus necessary to restore such rivers. Although interactions and mechanisms may differ between biomes and in larger or smaller rivers, available evidence suggests that large riparian trees may have similarly fundamental roles in the physical and biotic structuring of river valleys elsewhere in the temperate zone. Dead wood; woody debris; stream; river; habitat; fish
Seasonal and diel patterns in the migrations of fishes between a river and a floodplain tributary
The population behaviours associated with the migrations of fishes in lowland river ecosystems are amongst the most poorly-understood dispersal mechanisms of temperate freshwater organisms. This study evaluated the influence of four environmental variables (light levels, river discharge, water temperature and water velocity) on the timing, intensity and direction of fish movements between the River Avon (Hampshire, England) and a small floodplain tributary, Ibsley Brook, over a 12-month period. Using canonical correspondence analysis (CCA) to identify patterns of movement (by groups of species) and the relative strengths of explanatory variables in the data, the probability of fishes migrating between the river and tributary was determined using Bayesian modelling. The intensity and direction of fish movements between the river and tributary varied temporally, both on a diel and seasonal basis, and there were species- and age-specific patterns in behaviour. Diel movements appeared to be triggered by changes in light intensity and brook water velocity, whereas seasonal movements were mostly driven by changes in river discharge and water temperature, particularly those associated with floods. This study emphasises the importance of connectivity in river systems, as fishes migrated in all conditions, but especially during rapidly- rising discharge. ecosystem function; habitat connectivity; habitat fragmentation; habitat use; river discharge; water velocity
Protecting Wildlife Migration Corridors and Crucial Wildlife Habitat in the West
BACKGROUND 1. Large intact and functioning ecosystems, healthy fish and wildlife populations, and abundant public access to natural landscapes are a significant contributing factor to the West's economic and in-migration boom as well as quality of life. Critical wildlife migration corridors and crucial wildlife habitats are necessary to maintain flourishing wildlife populations. . 2. The Western States are particularly and uniquely affected by activity occurring in wildlife migration corridors and crucial wildlife habitats. Western States must also contend with an inter-connected mixture of private, state and federal lands. Migration corridors cross all political boundaries and States need to protect migration corridors on federal land through various state planning documents. 3. Natural resource development, urban development, and maintenance of the existing infrastructures of the West impact wildlife species, their habitats and migration corridors. Western States are increasingly expending limited state funds to participate in federal public land resource management planning as a result of the growing national focus on energy production and independence. States continue to expend scarce funds to protect or mitigate impacts to wildlife resources by energy development. 4. States possess broad trustee, police powers and primacy over fish and wildlife within their borders. With the exception of marine mammals, states retain concurrent jurisdiction even where Congress has directed specific federal authority of fish and wildlife speci
Simulating snowmelt process during rain-on-snow over a semi-arid mountain basin
In the Pacific Northwest of North America, significant flooding can occur during mid-winter rain-on-snow events. Warm, wet Pacific storms caused significant floods in the Pacific Northwest in February 1996, January 1997 and January 1998. Rapid melting of the mountain snow cover substantially augmented discharge during these flood events. An energy-balance snowmelt model is used to simulate snowmelt processes during the January 1997 event over a small headwater basin within the Reynolds Creek Experimental Watershed located in the Owyhee Mountains of southwestern Idaho, U.S.A. This sub-basin is 34% forested 12% fir, 22% aspen and 66% mixed sagebrush primarily mountain big sage- brush)). Data from paired open and forested experimental sites were used to drive the model. Model-forcing data were corrected for topographic and vegetation canopy effects. The event was preceded by cold, stormy conditions that developed a significant snow cover over the sub- basin. The snow cover at sites protected by forest cover was slightly reduced, while at open sites significant snowmelt occurred. The warm, moist, windy conditions during the flooding event produced substantially higher melt rates in exposed areas, where sensible- and latent- heat exchanges contributed 60^90% of the energy for snowmelt. Simulated snow-cover devel- opment and ablation during the model run closely matched measured conditions at the two experimental sites. This experiment shows the sensitivity of snowmelt processes to both climate and land cover, and illustrates how the forest canopy is coupled to the hydrologic cycle in mountainous areas.
Rain on Snow: Little Understood Killer in the North
n October 2003, a severe rain-on-snow (ROS) event killed approximately 20,000 musk-oxen (Figure 1) on Banks Island, which is the westernmost of the Canadian Arctic islands (approximately 380 kilome- ters by 290 kilometers in size). The event reduced the isolated herd by 25% and sig- nificantly affected the people dependent on the herd’s well-being. Because of the sparsity of weather stations in the Arctic and the lack of routinely deployed weather equipment that was capable of accurately sensing the ROS event, its detection largely was based on reports from hunters who were in the affected areas at the time.Such events can significantly alter a fro- zen ecosystem—with changes that often persist for the remainder of a winter—by creating ice layers at the surface of, within, or below the snowpack. The water and ice layers are known to facilitate the growth of toxic fungi, significantly warm the soil surface under thick snowpack, and deter large grazing mammals.
Influence of Timber Harvest on Rain-On-Snow Runoff: A Mechanism for Cumulative Watershed Effects
Rain-on-snow dominates many geomorphological processes in the Pacific Northwest. Wind-aided transfers of heat to snow during rain-on-snow comprise the largest source of heat for snowmelt during rainfall.␣ Recent field research in western. Oregon and western Washington has shown that timber harvest and thinning can increase both snow accumulation and the wind-aided transfers of heat, resulting in higher rates of water delivery to soil during rain-on-snow conditions.␣ Increased rates of water delivery to soil can lead to higher streamflows and to landslides on marginally stable slopes. Because of the magnitude of increase in water delivery to soils during common rain-on-snow conditions and a hydrologic recovery period that may require 40 years, rain-on-snow runoff is an important mechanism␣ whereby forest management activities might cumulatively affect water resources.
RAIN-ON-SNOW EVENTS IN THE WESTERN UNITED STATES
Severity of rain on snow depends on a number of factors, and an overall decrease in these events appears to be driven, in part, by changes in El Niño–Southern Oscillation.
THE SPATIAL AND TEMPORAL VARIABILITY OF RAIN-ON-SNOW
Snow melt during rainfall causes large-scale flooding and avalanching. These rain-on- snow events are most well-documented in the coastal mountain ranges of western North America. To determine what role they play in interior mountains, we analyzed flood frequencies in the Columbia River basin and modeled rain-on-snow potential from daily temperature and precipitation data. Applying the model with geographically distributed weather data allowed maps of rain-on-snow potential at 2km spatial resolution to be generated for characteristic climate years of 1982 (cold and wet), 1988 (warm and dry), and 1989 (average). It was found that rain-on-snow events are more likely during cool, wet years (such as 1982). A greater number of events and more widespread distribution of events occur during this type of climate. The cool temperatures allow low-elevation snow to accumulate and frequent storms bring the possibility of mid-winter rain. Warm, dry years (1988) are less likely to experience rain-on-snow events. There is little low-elevation snow at these times and only occasional precipitation. During all years, areas most susceptible to rain-on-snow are those where topography allows incursion of relatively warm, moist marine air that flows from the Pacific Ocean into the Columbia Plateau and up the Snake River Valley. These areas include the Cascade mountains; northern Idaho, northeastern Washington, and northwestern Montana where valleys open into the Columbia plateau; the Blue Mountains of northeastern Oregon; and western Wyoming and central Idaho adjacent to the Snake River. KEYWORDS: snow, avalanches, rain-on-snow, floods
