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Conservation - Scientific Papers

Brazil Matias Offline
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Gaia 2.0
Timothy M. Lenton, Bruno Latour
Science  14 Sep 2018:
Vol. 361, Issue 6407, pp. 1066-1068
DOI: 10.1126/science.aau0427

According to Lovelock and Margulis's Gaia hypothesis, living things are part of a planetary-scale self-regulating system that has maintained habitable conditions for the past 3.5 billion years (1, 2). Gaia has operated without foresight or planning on the part of organisms, but the evolution of humans and their technology are changing that. Earth has now entered a new epoch called the Anthropocene (3), and humans are beginning to become aware of the global consequences of their actions. As a result, deliberate self-regulation—from personal action to global geoengineering schemes—is either happening or imminently possible. Making such conscious choices to operate within Gaia constitutes a fundamental new state of Gaia, which we call Gaia 2.0. By emphasizing the agency of life-forms and their ability to set goals, Gaia 2.0 may be an effective framework for fostering global sustainability...

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Production of methane and ethylene from plastic in the environment
  • Sarah-Jeanne Royer,
  • Sara Ferrón,
  • Samuel T. Wilson,
  • David M. Karl  

*This image is copyright of its original author
  • Published: August 1, 2018
Abstract

Mass production of plastics started nearly 70 years ago and the production rate is expected to double over the next two decades. While serving many applications because of their durability, stability and low cost, plastics have deleterious effects on the environment. Plastic is known to release a variety of chemicals during degradation, which has a negative impact on biota. Here, we show that the most commonly used plastics produce two greenhouse gases, methane and ethylene, when exposed to ambient solar radiation. Polyethylene, which is the most produced and discarded synthetic polymer globally, is the most prolific emitter of both gases. We demonstrate that the production of trace gases from virgin low-density polyethylene increase with time, with rates at the end of a 212-day incubation of 5.8 nmol g-1 d-1 of methane, 14.5 nmol g-1 d-1 of ethylene, 3.9 nmol g-1 d-1 of ethane and 9.7 nmol g-1 d-1 of propylene. Environmentally aged plastics incubated in water for at least 152 days also produced hydrocarbon gases. In addition, low-density polyethylene emits these gases when incubated in air at rates ~2 times and ~76 times higher than when incubated in water for methane and ethylene, respectively. Our results show that plastics represent a heretofore unrecognized source of climate-relevant trace gases that are expected to increase as more plastic is produced and accumulated in the environment.

Introduction
Over the past 50 years, polymer manufacturing has accelerated, from 2x106 metric tonnes (Mt) per year in 1950 to 381x106 Mt per year in 2015, and is expected to double in the next 20 years [1]. The total global production of plastics to date is estimated at 8300x106 Mt, with polyethylene being the most common polymer [2,3], accounting for approximately 36% of all plastic types [1]. In the environment, plastics are vulnerable to weathering and degradation processes, caused by environmental factors such as light, heat, moisture, chemical oxidation and biological activity that are responsible for physical and chemical changes in the structure of the polymer [4].

Polyethylene, like other plastics, is not inert and is known to release additives and other degradation products into the environment throughout its lifetime. For example, the additive bisphenol-A used in the manufacture of many plastic products [5] is leached as plastics age, and hydrocarbon gases are produced during high-temperature decomposition (>202°C) [6]. These chemicals vary amongst different types of plastic and, once released, some can be toxic and have adverse effects on the environment and human health [79]. Degradation processes not only affect the chemical integrity of the plastic but also ultimately results in the fragmentation of the polymer into smaller units increasing the surface area exposed to the elements.

Most plastic is synthesized from natural gases [10] and leaching is expected to occur during the aging processes. However, to the best of our knowledge, no previous study has reported hydrocarbon gas emissions from plastics under natural conditions. This study seeks to investigate this phenomenon and its potential environmental consequences.

Our research investigated the production of hydrocarbon gases from polyethylene and other plastics at ambient temperature, with an emphasis on methane (CH4), one of the most potent atmospheric greenhouse gases [1113] and ethylene (C2H4), which reacts with OH in the atmosphere and increases carbon monoxide concentrations [14,15]. Given the substantial rise in plastic production worldwide, understanding the extent of CH4 and C2H4 emissions from plastic is essential. In addition, we report production rates of ethane (C2H6), the second most abundant hydrocarbon in the atmosphere after CH4, known to enhance the level of tropospheric ozone and carbon monoxide [14,16], and propylene (C3H6), also a hydrocarbon pollutant in the atmosphere [17]. Since plastics come in different compositions and morphologies, we conducted a series of experiments to evaluate gas production under a variety of environmental conditions. We show that solar radiation initiates the production of these gases for the polymers tested.

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Anthropogenic contamination of tap water, beer, and sea salt
  • Mary Kosuth  ,
  • Sherri A. Mason ,
  • Elizabeth V. Wattenberg  

*This image is copyright of its original author
  • Published: April 11, 2018
Abstract

Plastic pollution has been well documented in natural environments, including the open waters and sediments within lakes and rivers, the open ocean and even the air, but less attention has been paid to synthetic polymers in human consumables. Since multiple toxicity studies indicate risks to human health when plastic particles are ingested, more needs to be known about the presence and abundance of anthropogenic particles in human foods and beverages. This study investigates the presence of anthropogenic particles in 159 samples of globally sourced tap water, 12 brands of Laurentian Great Lakes beer, and 12 brands of commercial sea salt. Of the tap water samples analyzed, 81% were found to contain anthropogenic particles. The majority of these particles were fibers (98.3%) between 0.1–5 mm in length. The range was 0 to 61 particles/L, with an overall mean of 5.45 particles/L. Anthropogenic debris was found in each brand of beer and salt. Of the extracted particles, over 99% were fibers. After adjusting for particles found in lab blanks for both salt and beer, the average number of particles found in beer was 4.05 particles/L with a range of 0 to 14.3 particles/L and the average number of particles found in each brand of salt was 212 particles/kg with a range of 46.7 to 806 particles/kg. Based on consumer guidelines, our results indicate the average person ingests over 5,800 particles of synthetic debris from these three sources annually, with the largest contribution coming from tap water (88%).

Introduction
The first peer-reviewed papers to document plastic pollution in the natural world were published over 45 years ago [1,2]. Since then, a robust body of work has accumulated, and the ubiquity of synthetic polymers in the environment is now undisputed. From abandoned gillnets hundreds of meters in length to plankton sized fragments, synthetic polymers have been extracted from remote corners of the Earth’s biosphere. Plastics have been quantified in marine environments [3] that include segments of the pelagic biome [4] coastal habitats [5], deep sea sediments [6, 7], as well as freshwater lakes [8,9] and associated tributaries [10]. Particles have also turned up in Arctic sea ice [11], ambient air [12], and a plethora of biota such as seabirds [13, 14], aquatic mammals [15], fish [16], and benthic invertebrates [17].

The last 45 years have also seen a commensurate increase in plastic production as the total global output of 30 million tons in 1970 climbed to 322 million tons in 2015 [18]. Hopes of closing the loop on the plastic waste stream depend on overall recycling rates, which vary widely across the globe, even among developed nations with well-established recycling infrastructure. Europe, for example, recycled 26% of disposable plastics in 2012, while the United States (US) reported rates as low as 8.8% in the same year [19].

The heterogeneous nature of microplastics make them a challenge to study. Although they are referred to in the literature as synthetic polymers derived from petrochemicals that are less than 5 mm in length, a universally accepted definition does not exist. Plastics in general represent a wide range of materials, each with unique physical characteristics and chemical compositions. Roughly 90% of plastic produced globally, however, falls into one of six categories: HDPE, LDPE, PP, PVC, PS, and PET [20].

Plastics are hydrophobic and have been known to adsorb chemicals from the environment such as PCBs, PBDEs, and PAHs [21], some of which are known reproductive toxicants and carcinogens [22, 23, 24]. Plastic can also adsorb metals [25] and bacteria [26], sometimes at concentrations many times higher than their immediate surroundings [27]. Furthermore, there is evidence that once ingested some of these organic chemicals can desorb in the guts of animals [28]. Plastics can also leach synthetic additives, such as phthalates, alkylphenols, and bisphenol A [29]. A more recent study indicates that plastics can be cytotoxic to human cells [30]. Finally, plastic debris can serve as a unique microhabitat for marine organisms [31, 32] and aid in the transport of invasive species [33]. These known issues highlight why microplastics are considered a contaminant of emerging concern [34, 35, 36].

While evidence of plastic pollution in the natural world quickly mounts, few studies focus on synthetic polymer contamination in human consumables. A 2014 publication reported synthetic polymers in 24 brands of German beer [37]. Another study published the following year found microplastics in 15 brands of Chinese commercial salt sourced from lakes, mines, and coastal seas [38]. Two more studies of salt emerged in 2017; one reported the presence of plastic particles in globally sourced commercial salt [39] while the other found plastic particles in Spanish table salt [40]. Anthropogenic debris was also found in both fish and bivalves that were purchased in markets, intended for human consumption [35]. The known accumulation of anthropogenic debris in global water bodies makes contamination of human consumables sourced from those water bodies very likely. This study and others that predate it, seek to provide evidence of this contamination.

Our study focused on three common human consumables: beer, sea salt, and tap water. One objective of this study was to determine if the findings from previous studies [32, 33, 34, 35] regarding beer and salt are regional anomalies or pieces of a larger, global food and beverage contamination issue. For this reason, we analyzed contamination of beer and salt products purchased within the US [33, 34, 35]. We specifically analyzed beers brewed from water sourced from the Laurentian Great Lakes because of the known prominence of plastic pollution within those bodies of water. Internationally sourced salts purchased in the city of Minneapolis were chosen because when it comes to products such as salt, local markets often sell globally sourced products.

Another major objective of this study was to begin surveying contamination of drinking water. To the authors’ knowledge, no survey of anthropogenic debris in tap water has ever been published. We analyzed 159 water samples collected from fourteen countries. The samples, provided by Orb Media, span seven geographical regions from five continents. Approximately half of the samples came from developed countries and the other half from developing countries. The samples, representing both rural and urban communities, were subjected to different filtering methods and were used for different purposes. This broad survey provides an indication of whether the levels of contamination differ between developing and developed nations, and serves as a foundation for future studies that can focus on more specific questions regarding tap water contamination.

Anthropogenic contamination of tap water, beer, and sea salt
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Contrasting evolutionary history, anthropogenic declines and genetic contact in the northern and southern white rhinoceros (Ceratotherium simum)
Yoshan MoodleyIsa-Rita M. RussoJan RobovskýDesiré L. DaltonAntoinette KotzéSteve SmithJan StejskalOliver A. RyderRobert HermesChris WalzerMichael W. Bruford
Published 7 November 2018.DOI: 10.1098/rspb.2018.1567
Abstract
The white rhinoceros (Ceratotherium simum) has a discontinuous African distribution, which is limited by the extent of sub-Saharan grasslands. The southern population (SWR) declined to its lowest number around the turn of the nineteenth century, but recovered to become the world's most numerous rhinoceros. In contrast, the northern population (NWR) was common during much of the twentieth century, declining rapidly since the 1970s, and now only two post-reproductive individuals remain. Despite this species's conservation status, it lacks a genetic assessment of its demographic history. We therefore sampled 232 individuals from extant and museum sources and analysed ten microsatellite loci and the mtDNA control region. Both marker types reliably partitioned the species into SWR and NWR, with moderate nuclear genetic diversity and only three mtDNA haplotypes for the species, including historical samples. We detected ancient interglacial demographic declines in both populations. Both populations may also have been affected by recent declines associated with the colonial expansion for the SWR, and with the much earlier Bantu migrations for the NWR. Finally, we detected post-divergence secondary contact between NWR and SWR, possibly occurring as recently as the last glacial maximum. These results suggest the species was subjected to regular periods of fragmentation and low genetic diversity, which may have been replenished upon secondary contact during glacial periods. The species's current situation thus reflects prehistoric declines that were exacerbated by anthropogenic pressure associated with the rise of late Holocene technological advancement in Africa. Importantly, secondary contact suggests a potentially positive outcome for a hybrid rescue conservation strategy, although further genome-wide data are desirable to corroborate these results.

1. Introduction
The white rhinoceros (Ceratotherium simum) is the most common of the world's five remaining rhinoceros species. It has borne the brunt of rhinoceros losses during the global acceleration in illegal hunting, which began in 2008 because of increasing demand for horn products in southeast and east Asia. The species is an obligate grazer, thriving historically in two geographically separated grassland areas in sub-Saharan Africa, and has consequently been divided by taxonomists. The southern white rhinoceros (SWR) is endemic to southern Africa, historically occurring in much of the sub-region, south of the Zambezi river, including Namibia, Botswana, Zimbabwe and South Africa (electronic supplementary material, figure S1A,B, after [1]). The northern white rhinoceros (NWR) was endemic to a narrow belt of grassland from west of the Nile River and Albertine Rift, comprising parts of Uganda, South Sudan, the Democratic Republic of the Congo (DRC), Chad and the Central African Republic (electronic supplementary material, figure S1A,B). The recent histories of both populations are well known and independent, and contrastingly reflect events occurring in Africa and the Middle East since the eighteenth century (electronic supplementary material, figure S1C).

In southern Africa, the northwards spread of colonialism from the Cape of Good Hope resulted in the extermination of the SWR across most of the sub-region [2]. Even before the turn of the nineteenth century, the SWR had undergone a population decline so severe that only 100–200 individuals remained, restricted to around the confluence of the Black and White Umfolozi Rivers in Zululand [3]. However, in 1895 colonial authorities declared the white rhinoceros royal game and proclaimed the area the Umfolozi Junction Reserve [4]. With the dedicated conservation action of wildlife authorities in South Africa, this small population increased steadily throughout the twentieth century (electronic supplementary material, figure S1C) to become a conservation success story. The current severe poaching epidemic is threatening to undo these gains, and it is predicted that if present trends continue, the SWR population will start to decline again in 2018 [5]. Efforts to curb recent losses are ineffective with only marginal decreases in poaching rates in 2015 and 2016, with more than 1000 African rhinoceros killed every year since 2013. Such a population contraction, in the absence of gene flow from other sources, could negatively affect the genetic diversity and evolutionary potential of the SWR through genetic drift.

The demographic recovery of the SWR is all the more remarkable because the twentieth century also brought the near eradication of all other rhinoceros populations across the world. The NWR was still common throughout most of its range at the turn of the nineteenth century [6,7], and numbers were still relatively high until the 1960s [8], when demand for rhino horn, mainly on the Arabian peninsula, precipitated the penultimate poaching epidemic. Political instability and ineffective conservation measures during the ensuing period saw the rapid decline of NWR numbers in the wild (electronic supplementary material, figure S1C), with the last wild individuals extirpated in Uganda by 1980 [9], in Sudan by 1984 [8] and finally in Garamba National Park, Democratic Republic of the Congo [10], declared extinct in 2008. The NWR now survives only in captivity, and with two post-reproductive females remaining, its chances of survival look bleak. The imminent extinction of the NWR has sparked several conservation efforts to prevent the loss of what little remains of the population's genetic diversity.

For a complete reading, follow the link: http://rspb.royalsocietypublishing.org/c...0/20181567
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Two excellent documents.

The consequences of replacing wildlife with
 livestock in Africa

Scientific Reports volume 7, Article number: 17196 (2017) 

Abstract

The extirpation of native wildlife species and widespread establishment of livestock farming has dramatically distorted large mammal herbivore communities across the globe. Ecological theory suggests that these shifts in the form and the intensity of herbivory have had substantial impacts on a range of ecosystem processes, but for most ecosystems it is impossible to quantify these changes accurately. We address these challenges using species-level biomass data from sub-Saharan Africa for both present day and reconstructed historical herbivore communities. Our analyses reveal pronounced herbivore biomass losses in wetter areas and substantial biomass increases and functional type turnover in arid regions. Fire prevalence is likely to have been altered over vast areas where grazer biomass has transitioned to above or below the threshold at which grass fuel reduction can suppress fire. Overall, shifts in the functional composition of herbivore communities promote an expansion of woody cover. Total herbivore methane emissions have more than doubled, but lateral nutrient diffusion capacity is below 5% of past levels. The release of fundamental ecological constraints on herbivore communities in arid regions appears to pose greater threats to ecosystem function than do biomass losses in mesic regions, where fire remains the major consumer.

Link: https://www.nature.com/articles/s41598-017-17348-4



Spiny plants, mammal browsers, and the 
origin of African savannas
Tristan Charles-Dominique, T. Jonathan Davies, Gareth P. Hempson, Bezeng S. Bezeng,  Barnabas H. Daru, Ronny M. Kabongo, 
Olivier Maurin, A. Muthama Muasya, Michelle van der Bank, and William J. Bond
PNAS September 20, 2016 113 (38) E5572-E5579; published ahead of print September 6, 2016 
Significance
Africa hosts contrasting communities of mammal browsers and is, thus, the ideal background for testing their effect on plant communities and evolution. In this study at the continental scale, we reveal which mammal browsers are most closely associated with spiny communities of trees. We then show a remarkable convergence between the evolutionary histories of these browsers (the bovids) and spiny plants. Over the last 16 My, plants from unrelated lineages developed spines 55 times. These convergent patterns of evolution suggest that the arrival and diversification of bovids in Africa changed the rules for persisting in woody communities. Contrary to our current understanding, our data suggest that browsers predate fire by millions of years as agents driving the origin of savannas.

Link: http://www.pnas.org/content/113/38/E5572
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(10-10-2018, 06:57 PM)Matias Wrote:
Anthropogenic contamination of tap water, beer, and sea salt
  • Mary Kosuth  ,
  • Sherri A. Mason ,
  • Elizabeth V. Wattenberg  

*This image is copyright of its original author
  • Published: April 11, 2018
Abstract

Plastic pollution has been well documented in natural environments, including the open waters and sediments within lakes and rivers, the open ocean and even the air, but less attention has been paid to synthetic polymers in human consumables. Since multiple toxicity studies indicate risks to human health when plastic particles are ingested, more needs to be known about the presence and abundance of anthropogenic particles in human foods and beverages. This study investigates the presence of anthropogenic particles in 159 samples of globally sourced tap water, 12 brands of Laurentian Great Lakes beer, and 12 brands of commercial sea salt. Of the tap water samples analyzed, 81% were found to contain anthropogenic particles. The majority of these particles were fibers (98.3%) between 0.1–5 mm in length. The range was 0 to 61 particles/L, with an overall mean of 5.45 particles/L. Anthropogenic debris was found in each brand of beer and salt. Of the extracted particles, over 99% were fibers. After adjusting for particles found in lab blanks for both salt and beer, the average number of particles found in beer was 4.05 particles/L with a range of 0 to 14.3 particles/L and the average number of particles found in each brand of salt was 212 particles/kg with a range of 46.7 to 806 particles/kg. Based on consumer guidelines, our results indicate the average person ingests over 5,800 particles of synthetic debris from these three sources annually, with the largest contribution coming from tap water (88%).

Introduction
The first peer-reviewed papers to document plastic pollution in the natural world were published over 45 years ago [1,2]. Since then, a robust body of work has accumulated, and the ubiquity of synthetic polymers in the environment is now undisputed. From abandoned gillnets hundreds of meters in length to plankton sized fragments, synthetic polymers have been extracted from remote corners of the Earth’s biosphere. Plastics have been quantified in marine environments [3] that include segments of the pelagic biome [4] coastal habitats [5], deep sea sediments [6, 7], as well as freshwater lakes [8,9] and associated tributaries [10]. Particles have also turned up in Arctic sea ice [11], ambient air [12], and a plethora of biota such as seabirds [13, 14], aquatic mammals [15], fish [16], and benthic invertebrates [17].

The last 45 years have also seen a commensurate increase in plastic production as the total global output of 30 million tons in 1970 climbed to 322 million tons in 2015 [18]. Hopes of closing the loop on the plastic waste stream depend on overall recycling rates, which vary widely across the globe, even among developed nations with well-established recycling infrastructure. Europe, for example, recycled 26% of disposable plastics in 2012, while the United States (US) reported rates as low as 8.8% in the same year [19].

The heterogeneous nature of microplastics make them a challenge to study. Although they are referred to in the literature as synthetic polymers derived from petrochemicals that are less than 5 mm in length, a universally accepted definition does not exist. Plastics in general represent a wide range of materials, each with unique physical characteristics and chemical compositions. Roughly 90% of plastic produced globally, however, falls into one of six categories: HDPE, LDPE, PP, PVC, PS, and PET [20].

Plastics are hydrophobic and have been known to adsorb chemicals from the environment such as PCBs, PBDEs, and PAHs [21], some of which are known reproductive toxicants and carcinogens [22, 23, 24]. Plastic can also adsorb metals [25] and bacteria [26], sometimes at concentrations many times higher than their immediate surroundings [27]. Furthermore, there is evidence that once ingested some of these organic chemicals can desorb in the guts of animals [28]. Plastics can also leach synthetic additives, such as phthalates, alkylphenols, and bisphenol A [29]. A more recent study indicates that plastics can be cytotoxic to human cells [30]. Finally, plastic debris can serve as a unique microhabitat for marine organisms [31, 32] and aid in the transport of invasive species [33]. These known issues highlight why microplastics are considered a contaminant of emerging concern [34, 35, 36].

While evidence of plastic pollution in the natural world quickly mounts, few studies focus on synthetic polymer contamination in human consumables. A 2014 publication reported synthetic polymers in 24 brands of German beer [37]. Another study published the following year found microplastics in 15 brands of Chinese commercial salt sourced from lakes, mines, and coastal seas [38]. Two more studies of salt emerged in 2017; one reported the presence of plastic particles in globally sourced commercial salt [39] while the other found plastic particles in Spanish table salt [40]. Anthropogenic debris was also found in both fish and bivalves that were purchased in markets, intended for human consumption [35]. The known accumulation of anthropogenic debris in global water bodies makes contamination of human consumables sourced from those water bodies very likely. This study and others that predate it, seek to provide evidence of this contamination.

Our study focused on three common human consumables: beer, sea salt, and tap water. One objective of this study was to determine if the findings from previous studies [32, 33, 34, 35] regarding beer and salt are regional anomalies or pieces of a larger, global food and beverage contamination issue. For this reason, we analyzed contamination of beer and salt products purchased within the US [33, 34, 35]. We specifically analyzed beers brewed from water sourced from the Laurentian Great Lakes because of the known prominence of plastic pollution within those bodies of water. Internationally sourced salts purchased in the city of Minneapolis were chosen because when it comes to products such as salt, local markets often sell globally sourced products.

Another major objective of this study was to begin surveying contamination of drinking water. To the authors’ knowledge, no survey of anthropogenic debris in tap water has ever been published. We analyzed 159 water samples collected from fourteen countries. The samples, provided by Orb Media, span seven geographical regions from five continents. Approximately half of the samples came from developed countries and the other half from developing countries. The samples, representing both rural and urban communities, were subjected to different filtering methods and were used for different purposes. This broad survey provides an indication of whether the levels of contamination differ between developing and developed nations, and serves as a foundation for future studies that can focus on more specific questions regarding tap water contamination.

Anthropogenic contamination of tap water, beer, and sea salt

A bit disgusting, but very informational about how much plastics really invade our everyday consumption.

In a first, microplastics found in human poop
"If all mankind were to disappear, the world would regenerate back to the rich state of equilibrium that existed ten thousand years ago."

- E.O Wilson
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( This post was last modified: 11-27-2018, 09:41 PM by Matias )

One of the best Scientific Papers on the subject,  supported by bibliographical references of the most expressive.

Megafauna and ecosystem function from the Pleistocene 
to the Anthropocene
Yadvinder Malhi, Christopher E. Doughty, Mauro Galetti, Felisa A. Smith, Jens-Christian Svenning, and John W. Terborgh

PNAS January 26, 2016 113 (4) 838-846; published ahead of print January 26, 2016 

Edited by Robert M. May, University of Oxford, Oxford, United Kingdom, and approved December 10, 2015
 (received for review October 6, 2015)

Abstract
Large herbivores and carnivores (the megafauna) have been in a state of decline and extinction since the Late Pleistocene, both on land and more recently in the oceans. Much has been written on the timing and causes of these declines, but only recently has scientific attention focused on the consequences of these declines for ecosystem function. Here, we review progress in our understanding of how megafauna affect ecosystem physical and trophic structure, species composition, biogeochemistry, and climate, drawing on special features of PNAS and Ecography that have been published as a result of an international workshop on this topic held in Oxford in 2014. Insights emerging from this work have consequences for our understanding of changes in biosphere function since the Late Pleistocene and of the functioning of contemporary ecosystems, as well as offering a rationale and framework for scientifically informed restoration of megafaunal function where possible and appropriate.

For hundreds of millions of years, an abundance of large animals, the megafauna, was a prominent feature of the land and oceans. However, in the last few tens of thousands of years—a blink of an eye on many evolutionary and biogeochemical timescales—something dramatic happened to Earth’s ecology; megafauna largely disappeared from vast areas, rendered either actually or functionally extinct (12). Only in small parts of the world do megafauna exist at diversities anything close to their previous state, and, in many of these remaining regions, they are in a state of functional decline through population depletion and range contraction. In the oceans, a similar process has occurred over the last few hundred years: although there has been little absolute extinction, there has been a dramatic decline in the abundance of whales and large fish through overharvesting (3). Both on land and in oceans, declines continue today (47).

Homo sapiens evolved and dispersed in a world teeming with giant creatures. Our earliest art forms, such as the haunting and mesmerizing Late Pleistocene cave paintings of Lascaux and Altamira, show that megafauna had a profound impact on the psyche and spirituality of our ancestors. To humans past and modern, they indicate resources, danger, power, and charisma, but, beyond these impacts, such large animals have profound and distinct effects on the nature and functioning of the ecosystems they inhabit.

Martin (8) first posited a major human role in past megafaunal disappearances, and, since then, much has been written on their patterns and causes and the relative importance of human effects, climate change, and other factors (815). Only recently has work begun to address the environmental consequences of this dramatic transition from a megafaunal to a nonmegafaunal world on Earth’s ecology, as manifested through vegetation cover (16), plant–animal interactions (17), ecosystem structure (1618), trophic interactions (7), fire regimes (19), biogeochemical cycling (20), and climate (2122).

In this paper, we review evidence for megafaunal impacts on ecosystem function, on timescales ranging from the Late Pleistocene to the present. Understanding the consequences of past extinctions is valuable for a number of reasons: in particular because the loss of megafauna may have an enduring but little-recognized legacy on the functioning of the contemporary biosphere. Much of our current understanding of ecosystem ecology and biogeochemistry has been developed in a world artificially depleted of giants. We explore what lessons can be learned from the impacts of past extinctions and declines for contemporary conservation and explore what role megafauna may have yet to play in maintaining and rebuilding viable and vibrant ecosystems.

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A socio-economic survey of pangolin hunting in Assam, Northeast India



*This image is copyright of its original author
Neil D’CruzeBhagat SinghAniruddha MookerjeeLauren A.HarringtonDavid W. Macdonald
03 December 2018

Abstract

India has been identified as a source country for the illegal international trade in endangered pangolins, “scaly mammalian anteaters”, widely considered as the “world’s most trafficked mammal”. In this study, we investigated the involvement of hunters belonging principally to three locally prominent tribes (Biate, Dimasa and Karbi) in Assam State, Northeast India. Based on the results of interviews with 141 individuals, we conclude that all three tribal groups engaged in pangolin hunting between 2011 and 2016. Although pangolin meat is used locally, we found that hunters largely targeted pangolins for their scales and that substantial commercial gain via urban middlemen has now supplanted low-level traditional use as the primary driver for this activity. On average, each hunter captured one pangolin per year with the potential to earn 9,000 INR (135 USD) for a single animal (equating to approximately four months average income). The majority of hunters (89%) stated that pangolins were less abundant than they were five years ago, which suggests off-take is unsustainable. All hunters interviewed appeared to hunt pangolins occasionally, regardless of tribe, demography or income, which suggests that any mitigation strategy should focus on rural hunters. Whilst interventions to reduce poverty are no doubt required, we argue that such interventions alone are unlikely to be effective in reducing pangolin hunting. Rather, there is a need for co-ordinated packages of mutually reinforcing interventions to address this pangolin hunting in a more comprehensive manner. In particular, implementing a demand reduction strategy targeting urban consumers is urgently required.

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