-
Evolutionary history and the effect of biodiversity on plant productivity
-
Loss of biological diversity because of extinction is one of the most pronounced changes to the global environment. For several decades, researchers have tried to understand how changes in biodiversity might impact biomass production by examining how biomass correlates with a number of biodiversity metrics (especially the number of species and functional groups). This body of research has focused on species with the implicit assumption that they are independent entities. However, functional and ecological similarities are shaped by patterns of common ancestry, such that distantly related species might contribute more to production than close relatives, perhaps by increasing niche breadth. Here, we analyze 2 decades of experiments performed in grassland ecosystems throughout the world and examine whether the evolutionary relationships among the species comprising a community predict how biodiversity impacts plant biomass production. We show that the amount of phylogenetic diversity within communities explained significantly more variation in plant community biomass than other measures of diversity, such as the number of species or functional groups. Our results reveal how evolutionary history can provide critical information for understanding, predicting, and potentially ameliorating the effects of biodiversity loss and should serve as an impetus for new biodiversity experiments.
Located in
Resources
/
Climate Science Documents
-
Executive Order -- Preparing the United States for the Impacts of Climate Change
-
President Obama signed an executive order that will begin to prepare the Nation for the impacts of climate change by undertaking actions to enhance climate preparedness and resilience.
Located in
News & Events
-
Experimental climate change weakens the insurance effect of biodiversity
-
Ecosystems are simultaneously affected by biodiversity loss and climate change, but we know little about how these factors interact. We predicted that climate warming and CO2-enrichment should strengthen trophic cascades by reducing the relative efficiency of predation-resistant herbivores, if herbivore consumption rate trades off with predation resistance. This weakens the insurance effect of herbivore diversity. We tested this prediction using experimental ocean warming and acidification in seagrass mesocosms. Metaanalyses of published experiments first indicated that consumption rate trades off with predation resistance. The experiment then showed that three common herbivores together controlled macroalgae and facilitated seagrass dominance, regardless of climate change. When the predation-vulnerable herbivore was excluded in normal conditions, the two resistant herbivores maintained top-down control. Under warming, however, increased algal growth outstripped control by herbivores and the system became algal-dominated. Consequently, climate change can reduce the relative efficiency of resistant herbivores and weaken the insurance effect of biodiversity.
Located in
Resources
/
Climate Science Documents
-
Experimental studies of dead-wood biodiversity — A review identifying global gaps in knowledge
-
The importance of dead wood for biodiversity is widely recognized but strategies for conservation exist only in some regions worldwide. Most strategies combine knowledge from observational and experimental studies but remain preliminary as many facets of the complex relationships are unstudied. In this first global review of 79 experimental studies addressing biodiversity patterns in dead wood, we identify major knowledge gaps and aim to foster collaboration among researchers by providing a map of previous and ongoing experiments. We show that research has focused primarily on temperate and boreal forests, where results have helped in developing evidence-based conservation strategies, whereas comparatively few such efforts have been made in subtropical or tropical zones. Most studies have been limited to early stages of wood decomposition and many diverse and functionally important saproxylic taxa, e.g., fungi, flies and termites, remain under-represented. Our meta-analysis confirms the benefits of dead-wood addition for biodiversity, particularly for saproxylic taxa, but shows that responses of non-saproxylic taxa are heterogeneous. Our analysis indicates that global conservation of organisms associated with dead wood would benefit most by prioritizing research in the tropics and other neglected regions, focusing on advanced stages of wood decomposition and assessing a wider range of taxa. By using existing experimental set-ups to study advanced decay stages and additional taxa, results could be obtained more quickly and with less effort compared to initiating new experiments.
Located in
Resources
/
Climate Science Documents
-
Exponential Decline of Deep-Sea Ecosystem Functioning Linked to Benthic Biodiversity Loss
-
Here, we present a global-scale study based on 116 deep-sea sites that relates benthic biodiversity to several independent indicators of ecosystem functioning and efficiency. We show that deep-sea ecosystem functioning is exponentially related to deep-sea biodiversity and that ecosystem efficiency is also exponentially linked to functional biodiversity. These results suggest that a higher biodiversity supports higher rates of ecosystem processes and an increased efficiency with which these processes are performed. The exponential relationships presented here, being consistent across a wide range of deep-sea ecosystems, suggest that mutually positive functional interactions (ecological facilitation) can be common in the largest biome of our biosphere.Conclusions: Our results suggest that a biodiversity loss in deep-sea ecosystems might be associated with exponential reductions of their functions. Because the deep sea plays a key role in ecological and biogeochemical processes at a global scale, this study provides scientific evidence that the conservation of deep-sea biodiversity is a priority for a sustainable functioning of the worlds’ oceans.
Located in
Resources
/
Climate Science Documents
-
Extent and scale of local adaptation in salmonid fishes: review and meta-analysis
-
What is the extent and scale of local adaptation (LA)? How quickly does LA arise? And what is its underlying molecular basis? Our review and meta-analysis on salmonid fishes estimates the frequency of LA to be B55–70%, with local populations having a 1.2 times average fitness advantage relative to foreign populations or to their perfor- mance in new environments. Salmonid LA is evident at a variety of spatial scales (for example, few km to41000 km) and can manifest itself quickly (6–30 generations). As the geographic scale between populations increases, LA is generally more frequent and stronger. Yet the extent of LA in salmonids does not appear to differ from that in other assessed taxa. Moreover, the frequency with which foreign salmonid populations outperform local populations (B23– 35%) suggests that drift, gene flow and plasticity often limit or mediate LA. The relatively few studies based on candidate gene and genomewide analyses have identified footprints of selection at both small and large geographical scales, likely reflecting the specific functional properties of loci and the associated selection regimes (for example, local niche partitioning, pathogens, parasites, photoperiodicity and seasonal timing). The molecular basis of LA in salmonids is still largely unknown, but differential expression at the same few genes is implicated in the convergent evolution of certain phenotypes. Collectively, future research will benefit from an integration of classical and molecular approaches to understand: (i) species differences and how they originate, (ii) variation in adaptation across scales, life stages, population sizes and environmental gradients, and (iii) evolutionary responses to human activities.
Located in
Resources
/
Climate Science Documents
-
Extreme climatic event drives range contraction of a habitat-forming species
-
Species distributions have shifted in response to global warming in all major ecosystems on the Earth. Despite cogent evidence for these changes, the underlying mechanisms are poorly understood and currently imply gradual shifts. Yet there is an increasing appreciation of the role of discrete events in driving ecological change. We show how a marine heat wave (HW) eliminated a prominent habitat-forming seaweed, Scytothalia dorycarpa, at its warm distribution limit, causing a range contraction of approximately 100km (approx. 5% of its global distribution). Seawater temperatures during the HW exceeded the seaweed’s physiological threshold and caused extirpation of marginal populations, which are unlikely to recover owing to life-history traits and oceanographic processes. Scytothalia dorycarpa is an important canopy-forming seaweed in temperate Australia, and loss of the species at its range edge has caused structural changes at the community level and is likely to have ecosystem-level implications. We show that extreme warming events, which are increasing in magnitude and frequency, can force step-wise changes in species distributions in marine ecosystems. As such, return times of these events have major implications for projections of species distributions and ecosystem structure, which have typically been based on gradual warming trends.
Located in
Resources
/
Climate Science Documents
-
Extreme contagion in global habitat clearance
-
Habitat clearance remains the major cause of biodiversity loss, with consequences for ecosystem services and for people. In response to this, many global conservation schemes direct funds to regions with high rates of recent habitat destruction, though some also emphasize the conservation of remaining large tracts of intact habitat. If the pattern of habitat clearance is highly contagious, the latter approach will help prevent destructive processes gaining a foothold in areas of contiguous intact habitat. Here, we test the strength of spatial contagion in the pattern of habitat clearance. Using a global dataset of land-cover change at 50 50 km resolution, we discover that intact habitat areas in grid cells are refractory to clearance only when all neighbouring cells are also intact. The likelihood of loss increases dramatically as soon as habitat is cleared in just one neighbouring cell, and remains high thereafter. This effect is consistent for forests and grassland, across biogeographic realms and over centuries, constituting a coherent global pattern. Our results show that landscapes become vulnerable to wholesale clearance as soon as threatening processes begin to penetrate, so actions to prevent any incursions into large, intact blocks of natural habitat are key to their long-term persistence.
Keywords: habitat loss; global change biology; conservation; wilderness
Located in
Resources
/
Climate Science Documents
-
Extreme Weather Events in Europe: preparing for climate change adaptation
-
This study arises from the concern that changes in weather patterns will be one of the principal effects of climate change and with these will come extreme weather. This is of considerable consequence in Europe as it impacts on the vulnerability of communities across the continent and exposes them to environmental risks.
It is now widely recognised that failures in international efforts to agree on the action necessary to limit global climate change mean that adaptation to its consequences is necessary and unavoidable (Solomon et al., 2007). The changes anticipated in the occurrence and character of extreme weather events are, in many cases, the dominant factor in designing adaptation measures. Policy communities within the EU have begun to consider appropriate responses to these changes and an EU adaptation strategy is under active development and implementation. There are also sectoral EU initiatives, for example on water shortages and heat waves, and, at a regional level, on planning for floods and storms. The basic and unavoidable challenge for decision makers is to find workable and cost-effective solutions when faced with increased probabilities of very costly adverse impacts. Information about the nature and scale of these changes is essential to guide decisions on appropriate solutions. Agenda-setting for climate change and adaptation has to take place in a social or/and political setting. Scientific information about temporal changes in the probability distributions of extreme weather events over Europe, the main focus of this report, is important for informing the social and political processes that it is hoped will lead to adequate climate-change adaptation measures in Europe.
This report is focused on providing a working-level assessment of the current state of the quantitative understanding of relevant extreme weather phenomena and their impacts.
Located in
Resources
/
Climate Science Documents
-
Fact Sheet: Riparian Restoration Decision Support Tool
-
An innovative web-based tool - funded by the Appalachian Landscape Conservation Cooperative (LCC) and developed by researchers from the U.S. Forest Service and
the University of Massachusetts - is allowing managers to rapidly identify high-priority riparian targets for restoration to make more resilient in preparation for changes in future climate. The Riparian Restoration Prioritization to Promote Climate Change Resilience (RPCCR) tool identifies vulnerable stream and riverbanks that lack tree cover and shade in coldwater stream habitats. By locating the best spots to plant trees in riparian zones, resource managers can provide shade that limits the amount of solar radiation heating the water and reduces the impacts from climate change. This well-established management strategy will benefit high-elevation, cold-water aquatic communities.
Located in
Tools & Resources
/
Riparian Restoration Decision Support Tool
