scholarly journals Global distribution of mammal herbivore biomass reveals megafauna extinction patterns

2021 ◽  
Author(s):  
Fabio Berzaghi ◽  
Dan Zhu ◽  
John Alroy ◽  
Philippe Ciais
Keyword(s):  
Late Pleistocene ◽  
Dynamic Models ◽  
Earth System ◽  
Ecological Role ◽  
Nutrient Distribution ◽  
Large Herbivore ◽  
Northern Asia ◽  
Large Herbivores ◽  
Wild Mammals ◽  
Management Actions

Terrestrial mammalian herbivores strongly shape ecosystems and influence Earth system processes. Herbivorous mammals can alter vegetation structure, accelerate nutrient distribution, and modify carbon cycling. The Late Pleistocene megafauna extinctions triggered significant changes in ecosystems and climate, and current extinctions are having similarly pervasive consequences. A lack of global dynamic models of mammal populations limits our understanding of the ecological role of wild mammals and the consequences of their past and future extinctions. Here we present a global model of herbivore mammal populations defined by their ecological role based on a classification of all extant herbivores (n = 2599) in 24 functional groups. The eco-physiological model predicts present-day mammal biomass in natural conditions. Biomass hotspots occur in areas today dominated by humans, which account for 30% of biomass loss and limit future rewilding potentials. Large herbivore (body mass > 5 kg) biomass is higher in hot and wet areas with high evapotranspiration. Conversely, small herbivore biomass is more evenly distributed, particularly in colder climates. Thus, energy-water dependency is higher in large herbivores than smaller ones. Negative deviations from the biomass and water-energy relationship unveil past extinction patterns. Late Pleistocene extinctions may have triggered a collapse of biomass in Australia and South America and heavy losses in North America and northern Asia. The herbivore biomass estimates provide a quantitative benchmark for conservation and management actions. The herbivore model and the functional classification create new opportunities to integrate mammals into Earth system science.

scholarly journals Continuous presence of proto-cereals in Anatolia since 2.3 Ma, and their possible co-evolution with large herbivores and hominins

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Valérie Andrieu-Ponel ◽  
Pierre Rochette ◽  
François Demory ◽  
Hülya Alçiçek ◽  
Nicolas Boulbes ◽  
...  
Keyword(s):  
Large Herbivore ◽  
Large Lakes ◽  
Coprophilous Fungi ◽  
Large Herbivores ◽  
Genetic Modifications ◽  
Bioclimatic Zone ◽  
Central Resource ◽  
Sedimentary Core ◽  
Continuous Presence ◽  
Lake Acıgöl

AbstractCereals are a central resource for the human diet and are traditionally assumed to have evolved from wild grasses at the onset of the Neolithic under the pressure of agriculture. Here we demonstrate that cereals may have a significantly longer and more diverse lineage, based on the study of a 0–2.3 Ma, 601 m long sedimentary core from Lake Acıgöl (South-West Anatolia). Pollen characteristic of cereals is abundant throughout the sedimentary sequence. The presence of large lakes within this arid bioclimatic zone led to the concentration of large herbivore herds, as indicated by the continuous occurrence of coprophilous fungi spores in the record. Our hypothesis is that the effects of overgrazing on soils and herbaceous stratum, during this long period, led to genetic modifications of the Poaceae taxa and to the appearance of proto-cereals. The simultaneous presence of hominins is attested as early as about 1.4 Ma in the lake vicinity, and 1.8 Ma in Georgia and Levant. These ancient hominins probably benefited from the availability of these proto-cereals, rich in nutrients, as well as various other edible plants, opening the way, in this region of the Middle East, to a process of domestication, which reached its full development during the Neolithic.

Population structure, density and biomass of large herbivores in the tropical forests of Nagarahole, India

1992 ◽  
Vol 8 (01) ◽  
pp. 21-35 ◽  
Author(s):  
K. Ullas Karanth ◽  
Melvin E. Sunquist
Keyword(s):  
Population Structure ◽  
Tropical Forests ◽  
Primate Species ◽  
Line Transect ◽  
Large Herbivore ◽  
Large Herbivores ◽  
Transect Sampling ◽  
Structure Density ◽  
Density And Biomass ◽  
Turn Over

ABSTRACTWe studied the population structure, density and biomass of seven ungulate and two primate species in the tropical forests of Nagarahole, southern India, using line transect sampling and roadside/platform counts, during 1986–87. The estimated ecological densities of large herbivore species in the study area are: 4.2 muntjac km−2, 50.6 chital km−2, 5.5 sambar km−2, 0.8 four-horned antelope km−2, 9.6 gaur km−2, 4.2 wild pig km−2, 3.3 elephant km−2, 23.8 hanuman langur km−2and 0.6 bonnet macaque km−2. Most ungulates have female-biased adult sex ratios. Among common ungulate species, yearlings and young of the year comprise about a third of the population, suggesting relatively high turn-over rates. Three species (muntjac, sambar and four-horned antelope) are solitary, while others form groups. The study area supports a wild herbivore biomass density of 14,744 kg km−2. Among the three habitat types within the study area, biomass is lower in dry deciduous forests when compared with moist deciduous or teak plantation dominant forests. Using our results, we have examined the factors that may contribute towards maintenance of high ungulate biomass in tropical forests.

New Source of Dietary Data for Extinct Herbivores

1988 ◽  
Vol 30 (1) ◽  
pp. 92-97 ◽  
Author(s):  
William A. Akersten ◽  
Theresea M. Foppe ◽  
George T. Jefferson
Keyword(s):  
Late Pleistocene ◽  
Indirect Evidence ◽  
Bison Bison ◽  
Large Herbivores ◽  
Usual Assumption ◽  
Microhistological Analysis ◽  
Rancho La Brea ◽  
Very High ◽  
Control Study ◽  
Dietary Data

The teeth of many large herbivores contain “pockets” (fossettes, fossettids, etc.) which entrap impacted samples of food (dental boluses) during mastication. These do not preserve well in most fossil deposits, but at Rancho La Brea, paleobotanical remains survive essentially intact and dental boluses from late Pleistocene forms are amenable to microhistological analysis. Of the identifiable bolus contents, those from Bison antiquus averaged 87% nonmonocotyledons; from Camelops hesternus, 90% nonmonocotyledons; and from Equus occidentalis (one specimen), 56% nonmonocotyledons. A control study on modern Bison bison shows that the boluses contain somewhat lower percentages of monocotyledons than do alimentary samples from the same individuals. However, this accounts for only a part of the very high percentage of nonmonocotyledons in the boluses of the extinct Bison. We conclude that the populations of B. antiquus and C. hesternus represented at Rancho La Brea probably fed little on grasses and that there is enough indirect evidence to suggest that the same may be true for other populations of these taxa. The Equus data are not sufficient to do more than question the usual assumption that Pleistocene horses were always obligate grass eaters.

Large herbivores suppress liana infestation in an African savanna

2021 ◽  
Vol 118 (41) ◽  
pp. e2101676118
Author(s):  
Tyler C. Coverdale ◽  
Ryan D. O’Connell ◽  
Matthew C. Hutchinson ◽  
Amanda Savagian ◽  
Tyler R. Kartzinel ◽  
...  
Keyword(s):  
Stable State ◽  
Life Forms ◽  
Tree Canopy ◽  
Alternative Stable State ◽  
African Savanna ◽  
Large Herbivore ◽  
Large Herbivores ◽  
Woody Vines ◽  
Plant Life Forms ◽  
Canopy Area

African savannas are the last stronghold of diverse large-mammal communities, and a major focus of savanna ecology is to understand how these animals affect the relative abundance of trees and grasses. However, savannas support diverse plant life-forms, and human-induced changes in large-herbivore assemblages—declining wildlife populations and their displacement by livestock—may cause unexpected shifts in plant community composition. We investigated how herbivory affects the prevalence of lianas (woody vines) and their impact on trees in an East African savanna. Although scarce (<2% of tree canopy area) and defended by toxic latex, the dominant liana, Cynanchum viminale (Apocynaceae), was eaten by 15 wild large-herbivore species and was consumed in bulk by native browsers during experimental cafeteria trials. In contrast, domesticated ungulates rarely ate lianas. When we experimentally excluded all large herbivores for periods of 8 to 17 y (simulating extirpation), liana abundance increased dramatically, with up to 75% of trees infested. Piecewise exclusion of different-sized herbivores revealed functional complementarity among size classes in suppressing lianas. Liana infestation reduced tree growth and reproduction, but herbivores quickly cleared lianas from trees after the removal of 18-y-old exclosure fences (simulating rewilding). A simple model of liana contagion showed that, without herbivores, the long-term equilibrium could be either endemic (liana–tree coexistence) or an all-liana alternative stable state. We conclude that ongoing declines of wild large-herbivore populations will disrupt the structure and functioning of many African savannas in ways that have received little attention and that may not be mitigated by replacing wildlife with livestock.

Rewilding

Ecology ◽  
2019 ◽  
Author(s):  
Meredith Root-Bernstein
Keyword(s):  
The United States ◽  
Large Species ◽  
Large Carnivores ◽  
Apex Predators ◽  
Ecological Processes ◽  
Large Herbivore ◽  
Large Herbivores ◽  
True Nature ◽  
The Public ◽  
Wide Range

Rewilding is an increasingly recognized approach to conservation and restoration, among academics, land managers, and the public. Although a number of different definitions have been proposed for rewilding (see Definitions of Rewilding), most approaches called “rewilding” include ideas about restoring a habitat to a less-anthropogenic state, restoring ecological processes and allowing them to take their own course without managing for a target ecosystem condition and (re)-introducing missing (usually large) species as a way to restore those ecological processes. Conceptualizations of rewilding and actual rewilding projects draw on a wide range of cultural and ecological ideas and practical knowledge, which are detailed in this article. Several organizations now represent rewilding interests to policymakers and the public and set up or facilitate rewilding initiatives in Europe and the Americas. Much of their philosophies, practice, data, and outcomes are not published. The Wildland Research Institute is an influential source of research on wilderness mapping, rewilding, restoration, and policy analysis in Europe. The European Centre for Nature Conservation (ECNC) supports and facilitates the conservation of large herbivore populations and their habitats at large scales in Eurasia through its Large Herbivore Network. Rewilding Europe implements rewilding projects throughout Europe, bringing together financing for large herbivore reintroductions and luxury wilderness tourism. Their European Rewilding Network brings together rewilding-related services and knowledge exchange. Similarly, the True Nature Foundation is a European foundation that works to restore habitats, reintroduce primarily large herbivores, and create sustainable tourism in nature areas. Wild Europe seeks to promote and lobby for the protection of large, “wild” natural areas. Similarly, the European Wilderness Society is an advocacy organization that identifies and promotes the stewardship and protection of large wilderness areas. The Rewilding Foundation is an international organization promoting and working toward the conservation of large areas of habitat and corridors for large carnivores. The Wildlands Network is an American organization that similarly seeks to conserve and connect large habitat areas and reintroduce apex predators. The Rewilding Institute in the United States also promotes protecting large habitats and creating corridors for large carnivores. There are also numerous site-based rewilding projects, which largely preceded the consolidation of rewilding as a concept. Many of these, through their creative rethinking of ecological and paleo-ecological orthodoxy, have influenced the development of rewilding practice and theory.

scholarly journals Risks and opportunities of trophic rewilding for arthropod communities

2018 ◽  
Vol 373 (1761) ◽  
pp. 20170441 ◽  
Author(s):  
Roel van Klink ◽  
Michiel F. WallisDeVries
Keyword(s):  
Biodiversity Conservation ◽  
A Priori ◽  
Grey Literature ◽  
Control Treatment ◽  
Arthropod Communities ◽  
Large Herbivore ◽  
Large Herbivores ◽  
Natural Processes ◽  
Published Evidence ◽  
Eukaryotic Organisms

Trophic rewilding is a restoration strategy focusing on the restoration of trophic interactions to promote self-regulating, biodiverse ecosystems. It has been proposed as an alternative to traditional conservation management in abandoned or defaunated areas. Arthropods constitute the most species-rich group of eukaryotic organisms, but are rarely considered in rewilding. Here, we first present an overview of direct and indirect pathways by which large herbivores and predators affect arthropod communities. We then review the published evidence of the impacts of rewilding with large herbivores on arthropods, including grey literature. We find that systematic monitoring is rare and that a comparison with a relevant control treatment is usually lacking. Nevertheless, the available data suggest that when the important process of top-down control of large-herbivore populations is missing, arthropod diversity tends to decrease. To ensure that rewilding is supportive of biodiversity conservation, we propose that if natural processes can only partially be restored, substitutes for missing processes are applied. We also propose that boundaries of acceptable outcomes of rewilding actions should be defined a priori , particularly concerning biodiversity conservation, and that action is taken when these boundaries are transgressed. To evaluate the success of rewilding for biodiversity, monitoring of arthropod communities should be a key instrument. This article is part of the theme issue ‘Trophic rewilding: consequences for ecosystems under global change’.

scholarly journals Historical changes in land use influence current habitat preferences of large herbivores

2019 ◽  
Vol 34 (10) ◽  
pp. 2251-2259 ◽  
Author(s):  
Kajetan Perzanowski ◽  
Maciej Januszczak ◽  
Rafał Łopucki
Keyword(s):  
Land Use ◽  
Spatial Distribution ◽  
Habitat Preferences ◽  
Field Research ◽  
Study Data ◽  
European Bison ◽  
Large Herbivore ◽  
Large Herbivores ◽  
Historical Changes ◽  
Effective Factor

Abstract Context Predicting habitat use patterns is a key issue in the management of large herbivore populations. Particularly, indicators providing a model of the spatial distribution of a population in a simple way, without the necessity of laborious field research, are still being sought. Analysis of historical landscape changes can be one of such predictive tools. Objectives We tested the hypothesis that historical changes in land use can be used as an effective factor enabling prediction of spatial distribution. As a case study, data on habitat preferences of European bison Bison bonasus (wisents) were used. Methods Spatial distribution of 17302 records of the presence of wisents, collected over the period of 10 years, was compared using contemporary and historical habitat maps for the Bieszczady Mts. (Poland). The area of approx. 87 thousand ha was selected, where the density of human population decreased over four times, and the percentage of forests increased from over 30% to almost 80% due to land abandonment. Results Wisents were recorded significantly more frequently in parts of the forest that in the past were used for agriculture. We found that identification of parts of the forest overgrowing former cultivated fields makes it possible to predict the spatial distribution of wisent herds with very high probability. Conclusions Information on historical changes in land use can be used as a simple and effective factor enabling prediction of habitat selection by wisents. Such an approach can potentially be useful for similar assessments of other large wild herbivores.

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