scholarly journals The future of evolutionary diversity in reef corals

2015 ◽  
Vol 370 (1662) ◽  
pp. 20140010 ◽  
Author(s):  
Danwei Huang ◽  
Kaustuv Roy

One-third of the world's reef-building corals are facing heightened extinction risk from climate change and other anthropogenic impacts. Previous studies have shown that such threats are not distributed randomly across the coral tree of life, and future extinctions have the potential to disproportionately reduce the phylogenetic diversity of this group on a global scale. However, the impact of such losses on a regional scale remains poorly known. In this study, we use phylogenetic metrics in conjunction with geographical distributions of living reef coral species to model how extinctions are likely to affect evolutionary diversity across different ecoregions. Based on two measures—phylogenetic diversity and phylogenetic species variability—we highlight regions with the largest losses of evolutionary diversity and hence of potential conservation interest. Notably, the projected loss of evolutionary diversity is relatively low in the most species-rich areas such as the Coral Triangle, while many regions with fewer species stand to lose much larger shares of their diversity. We also suggest that for complex ecosystems like coral reefs it is important to consider changes in phylogenetic species variability; areas with disproportionate declines in this measure should be of concern even if phylogenetic diversity is not as impacted. These findings underscore the importance of integrating evolutionary history into conservation planning for safeguarding the future diversity of coral reefs.

2017 ◽  
Author(s):  
Richard J. Matear ◽  
Andrew Lenton

Abstract. Carbon-climate feedbacks have the potential to significantly impact the future climate by altering atmospheric CO2 concentrations (Zaehle et al., 2010). By modifying the future atmospheric CO2 concentrations, the carbon-climate feedbacks will also influence the future trajectory for ocean acidification. Here, we use the CO2 emissions scenarios from 4 Representative Concentration Pathways (RCPs) with an Earth System Model to project the future trajectories of ocean acidification with the inclusion of carbon-climate feedbacks. We show that simulated carbon-climate feedbacks can significantly impact the onset of under-saturated aragonite conditions in the Southern and Arctic Oceans, the suitable habitat for tropical coral and the deepwater saturation states. Under higher emission scenarios (RCP8.5 and RCP6.0), the carbon-climate feedbacks advance the onset of under-saturation conditions and the reduction in suitable coral reef habitat by a decade or more. The impact of the carbon-climate feedback is most significant for the medium (RCP4.5) and low emission (RCP2.6) scenarios. For RCP4.5 scenario by 2100, the carbon-climate feedbacks nearly double the area of surface water under-saturated respect to aragonite and reduce by 50 % the surface water suitable for coral reefs. For RCP2.6 scenario by 2100, the carbon-climate feedbacks reduce the area suitable for coral reefs by 40 % and increase the area of under-saturated surface water by 20 %. The high sensitivity of the impact of ocean acidification to the carbon-climate feedbacks in the low to medium emissions scenarios is important because our recent commitments to reduce CO2 emissions are trying to move us on to such an emissions scenario. The study highlights the need to better characterise the carbon-climate feedbacks to ensure we do not excessively stress the oceans by under-estimating the future impact of ocean acidification.


2017 ◽  
Vol 14 (6) ◽  
pp. 1739-1772 ◽  
Author(s):  
Kimberly K. Yates ◽  
David G. Zawada ◽  
Nathan A. Smiley ◽  
Ginger Tiling-Range

Abstract. Coral reefs serve as natural barriers that protect adjacent shorelines from coastal hazards such as storms, waves, and erosion. Projections indicate global degradation of coral reefs due to anthropogenic impacts and climate change will cause a transition to net erosion by mid-century. Here, we provide a comprehensive assessment of the combined effect of all of the processes affecting seafloor accretion and erosion by measuring changes in seafloor elevation and volume for five coral reef ecosystems in the Atlantic, Pacific, and Caribbean over the last several decades. Regional-scale mean elevation and volume losses were observed at all five study sites and in 77 % of the 60 individual habitats that we examined across all study sites. Mean seafloor elevation losses for whole coral reef ecosystems in our study ranged from −0.09 to −0.8 m, corresponding to net volume losses ranging from 3.4  ×  106 to 80.5  ×  106 m3 for all study sites. Erosion of both coral-dominated substrate and non-coral substrate suggests that the current rate of carbonate production is no longer sufficient to support net accretion of coral reefs or adjacent habitats. We show that regional-scale loss of seafloor elevation and volume has accelerated the rate of relative sea level rise in these regions. Current water depths have increased to levels not predicted until near the year 2100, placing these ecosystems and nearby communities at elevated and accelerating risk to coastal hazards. Our results set a new baseline for projecting future impacts to coastal communities resulting from degradation of coral reef systems and associated losses of natural and socioeconomic resources.


Author(s):  
Zane KALVITE ◽  
Zane LIBIETE ◽  
Arta BARDULE Arta BARDULE

Rise in human population, industrialization, urbanization, intensified agriculture and forestry pose considerable risks to water supply and quality both on global and regional scale. While freshwater resources are abundant in Latvia, during recent years increased attention has been devoted to water quality in relation to anthropogenic impacts. Forest cover in Latvia equals 52% and forest management and forest infrastructure building and maintenance are among the activities that may, directly or indirectly, affect water quality in headwater catchments. Sedimentation, eutrophication and export of hazardous substances, especially mercury (Hg), are of highest concern. To address these topics, several initiatives have started recently. In 2011, cooperation programme between Latvian State Forest Research Institute (LSFRI) “Silava” and JSC “Latvia’s State Forests” was launched to evaluate the impact of forest management on the environment. This programme included research on the efficiency of water protection structures used at drainage system maintenance (sedimentation ponds, overland flow) and regeneration felling (bufferzones). In 2016, within the second stage of this cooperation programme, a study on the impact of forest management on water quality (forest road construction, drainage system maintenance, felling) was started on a catchment scale. Since 2016 LSFRI Silava is partner in the Interreg Baltic Sea Region Programme project “Water management in Baltic forests”. By focusing on drainage systems, riparian zones and beaver activity, this project aims at reducing nutrient and Hg export from forestry sites to streams and lakes. While this project mostly has a demonstration character, it will also offer novel results on Hg and methylmercury (MeHg) concentrations in beaver ponds in all participating states. This paper aims at summarizing most important challenges related to the impact of forest management on water quality and corresponding recent initiatives striving to offer solutions.


2019 ◽  
Vol 3 (1) ◽  
pp. 20-39 ◽  
Author(s):  
Irus Braverman

Reef-building corals are increasingly exposed to warming ocean temperatures. Their immediate response to this rise in temperature is to expel their symbiotic algae and turn white, or bleach. It is mainly for these reasons that corals have been perceived by scientists as both a sign and a measure of the imminent catastrophe facing life in the oceans and, subsequently, on earth. To measure coral decline across space and time, coral scientists have come up with maps, indexes, and color-coded representations. Yet they soon realized that what they regard as today’s healthy reef is, in fact, yesterday’s depleted reef. This problem, referred to as the shifting baselines syndrome, renders most comparisons across time difficult and frustrates the ability to predict the future. The problem is exacerbated in the context of oceans, and further yet in the context of coral reefs, because of the lack of reliable historical records. In fact, many of the coral scientists I have interviewed perceive shifting baselines as one of the key challenges facing coral conservation scientists and managers in their attempts to accurately calculate coral decline—a project that is typically deemed necessary for effective management policies and restoration practices. My article will critically explore the application of, and the assumptions behind, the shifting baselines concept in the context of reef coral science. Specifically, I will draw on interviews with coral scientists to describe the practices and devices embedded in the creation of baselines for corals and, finally, I will explore how certain scientists are challenging the conceptions of nature and time that underlie their operations.


2011 ◽  
Vol 17 ◽  
pp. 95-110 ◽  
Author(s):  
Dennis K. Hubbard

Coral reefs have experienced a profound shift in community structure in recent decades, a pattern that contrasts with the apparent constancy of Caribbean reef zonation over the past 2 million years. The abrupt decline in branching Acropora palmata and massive frame-builders like Montastrea annularis in the Caribbean is troubling, and similar patterns have been reported from virtually every ocean. As we ponder the future of coral reefs, we must be mindful that our best monitoring records span perhaps half a century – and those are exceedingly rare. “Pristine” reefs may not have existed since Columbus sailed for the new world, and anthropogenic impacts probably extend even farther back in time.Despite the vagaries of evolutionary change, taphonomy and time averaging, the geologic record still represents a unique source of important information about the processes that have controlled community structure and reef building in the absence of human influences. The creation of rigid and elevated structures requires calcification rates that are capable of filling the accommodation space created by rising sea level. This has been complicated over the past three to four decades as accelerated sea-level rise has been joined by a suite of stresses that probably slow accretion. Explaining the recent reef decline and posing realistic models of future change will require an understanding of carbonate cycling in the past, the processes that have been involved and a quantitative assessment of how anthropogenic stresses are affecting both.At the least a look back in time may help to constrain the thresholds at which change might be expected to occur in the future. At best, the context gained from examining the “recent” geological past may provide insights into which possible solutions are most consistent with observed patterns at larger spatial and temporal scales.


2016 ◽  
Author(s):  
Kimberly K. Yates ◽  
David G. Zawada ◽  
Nathan A. Smiley ◽  
Ginger Tiling-Range

Abstract. Coral reefs serve as natural barriers that protect adjacent shorelines from coastal hazards such as storms, waves and erosion. Projections indicate global degradation of coral reefs due to anthropogenic impacts and climate change will cause a transition to net erosion by mid-century. Here, we provide a comprehensive assessment of the combined effect of all of the processes affecting seafloor accretion and erosion by measuring changes in seafloor elevation and volume for 5 coral reef ecosystems in the Atlantic, Pacific and Caribbean over the last several decades. Regional-scale mean elevation and volume losses were observed at all 5 study sites and in 78 % of the 59 individual habitats that we examined across all study sites. We estimate that 12 % to 65 % of seafloor elevation loss may be attributed to reduced carbonate production, bioerosion and carbonate dissolution and 35 % to 88 % may be attributed to physical erosion and export of sediment from these systems. Erosion of both coral-dominated substrate and non-coral substrate suggests that the current rate of carbonate production is no longer sufficient to support net accretion of coral reefs or adjacent habitats. We show that regional-scale loss of seafloor elevation and volume has accelerated the rate of relative sea level rise in these regions. Current water depths have increased to levels not predicted until near the year 2100, placing these ecosystems and nearby communities at elevated and accelerating risk to coastal hazards. Our results set a new baseline for projecting future impacts to coastal communities resulting from degradation of coral reef systems and associated losses of natural and socio-economic resources.


Author(s):  
Priyastiwi Priyastiwi

The purpose of this article is to provide the basic model of Hofstede and Grays’ cultural values that relates the Hofstede’s cultural dimensions and Gray‘s accounting value. This article reviews some studies that prove the model and develop the research in the future. There are some evidences that link the Hofstede’s cultural values studies with the auditor’s judgment and decisions by developing a framework that categorizes the auditor’s judgments and decisions are most likely influenced by cross-cultural differences. The categories include risk assessment, risk decisions and ethical judgments. Understanding the impact of cultural factors on the practice of accounting and financial disclosure is important to achieve the harmonization of international accounting. Deep understanding about how the local values may affect the accounting practices and their impacts on the financial disclosure are important to ensure the international comparability of financial reporting. Gray’s framework (1988) expects how the culture may affect accounting practices at the national level. One area of the future studies will examine the impact of cultural dimensions to the values of accounting, auditing and decision making. Key word : Motivation, leadership style, job satisfaction, performance


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