Present-day drivers do not explain biodiversity patterns in mammals
28 Jan 2020-Proceedings of the National Academy of Sciences of the United States of America (National Academy of Sciences)-Vol. 117, Iss: 4, pp 1836-1838
TL;DR: The authors used checklists of medium and large mammals from across four zoogeographic realms: Afrotropical, Indomalayan, Malagasy (Madagascar), and Neotropical, to determine the relative importance of different factors in driving patterns of mammalian biodiversity across the tropics and subtropics.
Abstract: Mammals are an obvious choice for analyses of global biodiversity patterns. They are not too diverse, disproportionately well studied, and even nonspecialists will be interested in the results. They are also fairly good indicators of overall vertebrate diversity (1). Moreover, the limited ability of most mammals to cross oceanic barriers and the lack of direct land connections between the Neotropics (South and Central America), Africa, Madagascar, Asia, and Australasia (Australia and New Guinea) provide an opportunity to compare more or less independent evolutionary responses to similar tropical and subtropical environments (2). Such comparisons are complicated, however, by the widespread impacts of climate change and human activities over the last 100,000 y, from the Late Pleistocene megafaunal extinctions to the ongoing consequences of recent human population growth and economic development across the tropics (3). Understanding the reasons for the similarities and differences within and between regions is of more than just theoretical interest, since it may also have practical importance for conservation management. In PNAS, Rowan et al. (4) address this issue and attempt to determine the relative importance of different factors in driving patterns of mammalian biodiversity across the tropics and subtropics.
They excluded smaller species (<500 g) from their analyses, greatly reducing the scale of the task, since most mammals are small rodents or bats, while greatly increasing the quality of the data available, since larger species are easier to find and study. They were then able to assemble an impressive dataset consisting of 515 checklists of medium and large mammals from across four zoogeographic realms: Afrotropical, Indomalayan, Malagasy (Madagascar), and Neotropical. They excluded tropical Australasia, presumably because there were too few complete checklists from this realm. The final dataset included 852 species, many of which are now under threat from hunting and/or habit loss. For each community, they …
[↵][1]1Email: corlett{at}xtbg.org.cn.
[1]: #xref-corresp-1-1
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TL;DR: The anthropogenic transformation of terrestrial biomes during and during the Industrial Revolution, from 1700 to 2000, was mapped and characterized by map comparisons at century intervals in this paper, and the transformation pathways differed strongly between biomes and regions, with some remaining mostly wild but with the majority almost completely transformed into rangelands, croplands and villages.
Abstract: Aim To map and characterize anthropogenic transformation of the terrestrial biosphere before and during the Industrial Revolution, from 1700 to 2000.
Location Global.
Methods Anthropogenic biomes (anthromes) were mapped for 1700, 1800, 1900 and 2000 using a rule-based anthrome classification model applied to gridded global data for human population density and land use. Anthropogenic transformation of terrestrial biomes was then characterized by map comparisons at century intervals.
Results In 1700, nearly half of the terrestrial biosphere was wild, without human settlements or substantial land use. Most of the remainder was in a seminatural state (45%) having only minor use for agriculture and settlements. By 2000, the opposite was true, with the majority of the biosphere in agricultural and settled anthromes, less than 20% seminatural and only a quarter left wild. Anthropogenic transformation of the biosphere during the Industrial Revolution resulted about equally from land-use expansion into wildlands and intensification of land use within seminatural anthromes. Transformation pathways differed strongly between biomes and regions, with some remaining mostly wild but with the majority almost completely transformed into rangelands, croplands and villages. In the process of transforming almost 39% of earth's total ice-free surface into agricultural land and settlements, an additional 37% of global land without such use has become embedded within agricultural and settled anthromes.
Main conclusions Between 1700 and 2000, the terrestrial biosphere made the critical transition from mostly wild to mostly anthropogenic, passing the 50% mark early in the 20th century. At present, and ever more in the future, the form and process of terrestrial ecosystems in most biomes will be predominantly anthropogenic, the product of land use and other direct human interactions with ecosystems. Ecological research and conservation efforts in all but a few biomes would benefit from a primary focus on the novel remnant, recovering and managed ecosystems embedded within used lands.
1,055 citations
TL;DR: A snapshot of how well the planet’s protected area system encompasses vertebrate biodiversity is provided, with substantial differences between the identified vertebrate priorities and the leading map of global conservation priorities, the biodiversity hotspots.
Abstract: Identifying priority areas for biodiversity is essential for directing conservation resources. Fundamentally, we must know where individual species live, which ones are vulnerable, where human actions threaten them, and their levels of protection. As conservation knowledge and threats change, we must reevaluate priorities. We mapped priority areas for vertebrates using newly updated data on >21,000 species of mammals, amphibians, and birds. For each taxon, we identified centers of richness for all species, small-ranged species, and threatened species listed with the International Union for the Conservation of Nature. Importantly, all analyses were at a spatial grain of 10 × 10 km, 100 times finer than previous assessments. This fine scale is a significant methodological improvement, because it brings mapping to scales comparable with regional decisions on where to place protected areas. We also mapped recent species discoveries, because they suggest where as-yet-unknown species might be living. To assess the protection of the priority areas, we calculated the percentage of priority areas within protected areas using the latest data from the World Database of Protected Areas, providing a snapshot of how well the planet’s protected area system encompasses vertebrate biodiversity. Although the priority areas do have more protection than the global average, the level of protection still is insufficient given the importance of these areas for preventing vertebrate extinctions. We also found substantial differences between our identified vertebrate priorities and the leading map of global conservation priorities, the biodiversity hotspots. Our findings suggest a need to reassess the global allocation of conservation resources to reflect today’s improved knowledge of biodiversity and conservation.
700 citations
TL;DR: It is shown that biotic migrations across the Isthmus of Panama began several million years earlier than commonly assumed, indicating that the dramatic biotic turnover associated with the Great American Biotic Interchange was a long and complex process that began as early as the Oligocene–Miocene transition.
Abstract: The linking of North and South America by the Isthmus of Panama had major impacts on global climate, oceanic and atmospheric currents, and biodiversity, yet the timing of this critical event remains contentious. The Isthmus is traditionally understood to have fully closed by ca. 3.5 million years ago (Ma), and this date has been used as a benchmark for oceanographic, climatic, and evolutionary research, but recent evidence suggests a more complex geological formation. Here, we analyze both molecular and fossil data to evaluate the tempo of biotic exchange across the Americas in light of geological evidence. We demonstrate significant waves of dispersal of terrestrial organisms at approximately ca. 20 and 6 Ma and corresponding events separating marine organisms in the Atlantic and Pacific oceans at ca. 23 and 7 Ma. The direction of dispersal and their rates were symmetrical until the last ca. 6 Ma, when northern migration of South American lineages increased significantly. Variability among taxa in their timing of dispersal or vicariance across the Isthmus is not explained by the ecological factors tested in these analyses, including biome type, dispersal ability, and elevation preference. Migration was therefore not generally regulated by intrinsic traits but more likely reflects the presence of emergent terrain several millions of years earlier than commonly assumed. These results indicate that the dramatic biotic turnover associated with the Great American Biotic Interchange was a long and complex process that began as early as the Oligocene–Miocene transition.
458 citations
Book•
14 Feb 2011
TL;DR: This book discusses the origins of the similarities and differences among rain forests, the role of primates, and the future of Tropical Rain Forests in the face of climate change.
Abstract: Preface to the first edition Preface to the second edition Acknowledgments 1 Many Tropical Rain Forests What are tropical rain forests? Where are the tropical rain forests? Rain forest environments Rain forest histories Origins of the similarities and differences among rain forests Many rain forests Conclusions 2 Plants: Building Blocks of the Rain Forest Plant distributions Rain forest structure How many plant species? Widespread plant families Neotropical rain forests Asian rain forests Rain forests in New Guinea and Australia African rain forests Madagascan rain forests Conclusions and future research directions 3 Primate Communities: A Key to Understanding Biogeography and Ecology What are primates? Old World versus New World primates Primate diets Primate communities Primates as seed dispersal agents Conclusions and future research directions 4 Carnivores and Plant-eaters Carnivores Herbivores of the forest floor Conclusions and future research directions 5 Birds: Linkages in the Rain Forest Community Biogeography Little, brown, insect-eating birds Forest frugivores Fruit size and body size Flower visitors Ground-dwellers Woodpeckers Birds of prey Scavengers Night birds Migration Comparison of bird communities across continents Conclusions and future research directions 6 Fruit Bats and Gliding Animals in the Forest Canopy Fruit- and nectar-feeding bats Flying behavior Foraging behavior Bats as pollinators and seed dispersal agents Gliding vertebrates Conclusions and future research directions 7 Insects: Diverse, Abundant, and Ecologically Important Butterflies Ants Termites Bees Conclusions and future research directions 8 Island Rain Forests Pacific islands Evolution on islands Indian Ocean islands Atlantic islands Caribbean islands Natural disasters Human impacts Conclusions and future research directions 9 The Future of Tropical Rain Forests Different forests, different threats The major threats The forces behind the threats Global climate change Saving the many rain forests Conclusions and future research directions References Index
219 citations
Griffith University1, Panthera Corporation2, University of Pretoria3, University of California4, State University of New York College of Environmental Science and Forestry5, University of Oxford6, African Wildlife Foundation7, Kenya Wildlife Service8, University of Melbourne9, Wildlife Conservation Society10, University of Cambridge11, University of KwaZulu-Natal12
TL;DR: African governments and the international community need to increase the funding available for management by three to six times if PAs are to effectively conserve lions and other species and provide vital ecological and economic benefits to neighboring communities.
Abstract: Protected areas (PAs) play an important role in conserving biodiversity and providing ecosystem services, yet their effectiveness is undermined by funding shortfalls. Using lions (Panthera leo) as a proxy for PA health, we assessed available funding relative to budget requirements for PAs in Africa’s savannahs. We compiled a dataset of 2015 funding for 282 state-owned PAs with lions. We applied three methods to estimate the minimum funding required for effective conservation of lions, and calculated deficits. We estimated minimum required funding as $978/km2 per year based on the cost of effectively managing lions in nine reserves by the African Parks Network; $1,271/km2 based on modeled costs of managing lions at ≥50% carrying capacity across diverse conditions in 115 PAs; and $2,030/km2 based on Packer et al.’s [Packer et al. (2013) Ecol Lett 16:635–641] cost of managing lions in 22 unfenced PAs. PAs with lions require a total of $1.2 to $2.4 billion annually, or ∼$1,000 to 2,000/km2, yet received only $381 million annually, or a median of $200/km2. Ninety-six percent of range countries had funding deficits in at least one PA, with 88 to 94% of PAs with lions funded insufficiently. In funding-deficit PAs, available funding satisfied just 10 to 20% of PA requirements on average, and deficits total $0.9 to $2.1 billion. African governments and the international community need to increase the funding available for management by three to six times if PAs are to effectively conserve lions and other species and provide vital ecological and economic benefits to neighboring communities.
85 citations