Abstract and Figures

Large herbivorous mammals, already greatly reduced by the late-Pleistocene extinctions, continue to be threatened with decline. However, many herbivorous megafauna (body mass ≥ 100 kg) have populations outside their native ranges. We evaluate the distribution, diversity and threat status of introduced terrestrial megafauna worldwide and their contribution towards lost Pleistocene species richness. Of 76 megafauna species, 22 (∼29%) have introduced populations; of these eleven (50%) are threatened or extinct in their native ranges. Introductions have increased megafauna species richness by between 10% (Africa) and 100% (Australia). Furthermore, between 15% (Asia) and 67% (Australia) of extinct species richness, from the late Pleistocene to today, have been numerically replaced by introduced megafauna. Much remains unknown about the ecology of introduced herbivores, but evidence suggests that these populations are rewilding modern ecosystems. We propose that attitudes towards introduced megafauna should allow for broader research and management goals.
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megafauna have been moved to new regions and between
continents. Introductions of megafauna worldwide may
have inadvertently provided refuge for threatened mega-
fauna, increased regional large herbivore species richness, and
restored or added ecological functions. Acknowledgement
of this possibility is being fostered by the burgeoning con-
cept of ‘ rewilding, ’ which includes eff orts to proactively
introduce species in order to provide refuge and to restore
lost ecological processes (Donlan et al. 2006, Svenning
et al. 2016). However, much remains unknown about the
contribution of already introduced populations to global
conservation goals.
Given that introduced populations are often unwanted
and considered components of anthropogenic harm, the
existence of populations that are simultaneously introduced
and threatened or extinct in their native ranges has been
highlighted as a conservation paradox (Marchetti and
Engstrom 2015). Indeed, the considerable redistribution
of biota that characterizes the Anthropocene may be a
countercurrent to the extinction crisis by providing refuge
and new opportunities for threatened species (Wallach et al.
2015). However, comprehensive analyses of the interaction
between the processes of extinction and redistribution have
not been conducted.
To assess the potential conservation values of introduced
megafauna we compiled current information on their threat
statuses and population trends in their native ranges, their
relative population sizes in and out of their native ranges,
and their functional roles. To understand how introduced
megafauna have potentially rewilded the world, we assessed
Ecography 40: 001–010, 2017
doi: 10.1111/ecog.03430
© 2017  e Authors. Ecography © 2017 Nordic Society Oikos
Subject Editor: Jacquelyn Gill. Editor-in-Chief: Hanna Tuomisto. Accepted 24 July 2017
Terrestrial herbivorous megafauna are undergoing severe
declines around the world. Of 74 extant large terrestrial her-
bivorous mammal species with body masses 100 kg, 44
( 60%) are threatened with extinction (Ripple et al. 2015).
e decline of this functional group began 10 000 50 000 yr
ago, most likely due to overhunting by humans during the
late Pleistocene (Barnosky et al. 2004, Bartlett et al. 2015).
Large ( 100 kg) herbivorous megafauna (henceforth
megafauna ) perform distinct roles that contribute to the
functioning of ecological systems. Megafauna consume
brous vegetation, which can benefi t smaller herbivores,
reduce fi re risk, accelerate rates of nutrient cycling by orders
of magnitude, and shift plant community structure by
facilitating coexistence between diff erent plant functional
types. Due to their large size, these organisms cause physi-
cal disturbance and disperse large seeds and nutrients great
distances (Ripple et al. 2015).  e considerable loss of this
functionality at the end of the Pleistocene had dramatic eff ects
on plant community structure, fi re regimes, nutrient and
mineral cycling across landscapes, and community assembly
(Gill et al. 2009, Ripple and Van Valkenburgh 2010, Smith
et al. 2015, Bakker et al. 2016a, Doughty et al. 2016a, b,
c, Malhi et al. 2016). Modern declines have similar conse-
quences for terrestrial ecosystems and community dynam-
ics (Ripple et al. 2015) and have led to broad international
calls for immediate action to conserve the world s remaining
mammalian megafauna (Ripple et al. 2016, 2017).
Less well considered is the role of megafauna introductions
on their conservation and on ecosystem function. Since the
advent of the Anthopocene, particularly in the past 200 yr,
Introduced megafauna are rewilding the Anthropocene
Erick J. Lundgren , Daniel Ramp , William J. Ripple and Arian D. Wallach
E. J. Lundgren (http://orcid.org/0000-0001-9893-3324) (elundgr2@asu.edu), Arizona State Univ., School of Life Sciences, Tempe, AZ, USA.
D. Ramp, A. D. Wallach and EJL, Centre for Compassionate Conservation, School of Life Sciences, Univ. of Technology Sydney, NSW, Australia.
W. J. Ripple, Global Trophic Cascades Program, Dept of Forest Ecosystems and Society, Oregon State Univ., Corvallis, OR, USA .
Large herbivorous mammals, already greatly reduced by the late-Pleistocene extinctions, continue to be threatened with
decline. However, many herbivorous megafauna (body mass 100 kg) have populations outside their native ranges. We
evaluate the distribution, diversity and threat status of introduced terrestrial megafauna worldwide and their contribution
towards lost Pleistocene species richness. Of 76 megafauna species, 22 ( 29%) have introduced populations; of these eleven
(50%) are threatened or extinct in their native ranges. Introductions have increased megafauna species richness by between
10% (Africa) and 100% (Australia). Furthermore, between 15% (Asia) and 67% (Australia) of extinct species richness,
from the late Pleistocene to today, have been numerically replaced by introduced megafauna. Much remains unknown
about the ecology of introduced herbivores, but evidence suggests that these populations are rewilding modern ecosystems.
We propose that attitudes towards introduced megafauna should allow for broader research and management goals.
the contribution of introduced megafauna to continental
assemblages, and the contribution of introduced megafauna
to Anthropocene richness relative to the Holocene and
Pleistocene epochs.
We searched for introduced populations of herbivorous
megafauna (mammals only) with body masses 100 kg
based on Ripple et al. (2015) using Long (2003) and supple-
mented with online searches (Google Scholar and Google)
using the terms ‘ feral ’ , ‘ introduced ’ , ‘ invasive ’ , ‘ exotic ’ and
non-native . We used grey literature (e.g. government
reports) and journalism sources (e.g.  e New York Times)
alongside peer-reviewed literature to identify megafauna
populations outside their native ranges. Data collection con-
cluded in July, 2017. While some native megafauna popu-
lations live in fenced and managed conditions (e.g. Kruger
National Park), only free-roaming wild introduced popula-
tions were included because it was not clear if fenced/man-
aged introduced populations are ecologically viable in their
new homes.
To understand to what extent introduced megafauna
represent the taxonomic diversity of the world s remaining
megafauna, we calculated the number of large herbivore
families represented by introduced species, the number of
genera of each family represented by introduced species, and
the percentage of species with introduced populations within
each taxonomic family.
To determine the potential conservation value of intro-
duced megafauna as refuge populations, we compiled
IUCN (2017) Red List threat statuses and trends in each
species historic native ranges and the proportion of each
population that is currently outside of its native range
(Supplementary material Appendix 2 Table A1). Wild
post-domestic species were assigned the threat status of
their pre-domestic ancestor. For example, introduced wild
dromedary camels Camelus dromedarius originate from the
domesticated form of an extinct camel species (possibly
C. thomasi ), and were therefore considered extinct in the
wild in their native range.
To understand to what geographic extent introduced
megafauna have rewilded the world, we calculated mega-
fauna species richness by Taxonomic Databases Working
Group level 3 countries (henceforth TDWG), which are
bio-geographic units defi ned by political (nation, state, prov-
ince, or district) boundaries at a biologically relevant scale
(Brummitt 2001). Inter- and intra-continental introduc-
tions were included in this comparison.  e distributions
of introduced megafauna were determined from literature
and Google searches (Supplementary material Appendix 1
Data A1). Geographic ranges for native megafauna were
downloaded from the IUCN (2017) Red List.  e percent-
age of each TDWG country s megafauna assemblage that is
introduced was calculated and compared between continents
to understand how introductions have altered continental
megafauna assemblages.
We assessed how Anthropocene megafauna richness com-
pares to those of past geological epochs. For each continent,
we compared megafauna species richness and conservation
status between the late Pleistocene (50 000 10 000 BP),
Holocene ( 10 000 BP), and Anthropocene (past 200 yr)
epochs. Only inter-continental introduced megafauna were
Pleistocene species were classifi ed as ‘ extinct ’ , ‘ extir-
pated or survived based on their fate through the late-
Pleistocene extinction. Pleistocene megafauna presence was
based on Sandom et al. (2014) and body masses ( 100 kg)
were confi rmed through literature searches.  e Holocene
included species from the end of the Pleistocene until the
Anthropocene. Holocene species included survived taxa,
natural immigrants, and species that went extinct during
the Holocene (e.g. aurochs Bos primigenius and dromedary
camel). Anthropocene species included ‘ survived ’ , ‘ survived,
threatened ’ , ‘ introduced ’ , and ‘ introduced, threatened ’ spe-
cies, refl ecting their current IUCN (2017) threat statuses
(Supplementary material Appendix 3 Table A2).
To describe the range of functional traits of introduced
megafauna, we reviewed their average body masses, habitat
types, dietary types (grazer, browser, or intermediate), and
other unique traits using the IUCN (2017) and published
Twenty-two (32%) of the 76 extant megafauna species have
established wild populations outside their native ranges
(Supplementary material Appendix 2 Table A1). Sixteen are
inter-continental introductions, two are intra-regional but
overcame oceanic barriers, and four are intra-continental.
By including post-domesticates of extinct heritage, an addi-
tional two species (the dromedary camel and cattle Bos tau-
rus ) are added to the 74 remaining native megafauna. Six
additional species were excluded from analysis: three species
because they appear to be confi ned to game ranches, one
because introduced populations are described as semi-wild,
and two because of uncertain taxonomic relation to already
included species.
Six (55%) of the eleven families containing megafauna
species have established populations outside their native
ranges. Introduced species represent between 29% (Equidae)
and 56% (Cervidae) of the megafauna species within their
families (Fig. 1). Likewise, introduced populations repre-
sent between 50% (Camelidae) and 100% (Equidae) of the
megafauna genera within their families.
Of the 22 species with introduced populations, eleven
(50%) are threatened or extinct in their native ranges (Fig. 2).
is includes four ( 18%) Vulnerable non-domesticated
species, three (14%) post-domestics whose progenitors are
Endangered, one ( 5%) Endangered non-domesticated spe-
cies, two (9%) post-domestic species whose wild progenitors
are Extinct, and one ( 5%) post-domestic whose progeni-
tor is Critically Endangered. All six post-domestic species are
extinct or threatened in their native ranges. Of the remain-
ing eleven introduced megafauna, three (14%) are Near
reatened, and eight are ranked as Least Concern in their
native ranges, of which 50% have stable population trends,
22% are increasing, and 11% are declining (Fig. 2). Of the
20 introduced species with surviving native populations,
eleven (55%) are declining in their native ranges, fi ve (25%)
are stable, and four (20%) are increasing (Supplementary
material Appendix 2 Table A1). In all, 64% of introduced
megafauna are threatened or declining in their native ranges
(Fig. 2).
On average, over 38% (ranging between 1 and 100%)
of megafauna populations are outside of their native
ranges. Whereas two species have relatively small (possibly
100 individuals) populations outside their native ranges
(hippopotamus Hippopotamus amphibius , and Asian ele-
phant Elephas maximus ), twelve populations are estimated in
the thousands and up to over 1 million individuals (Fig. 3,
Supplementary material Appendix 2 Table A1).
By including introduced megafauna, the worldwide
distribution of megafauna species richness increases sig-
nifi cantly (Fig. 4). Introduced megafauna have sub-
stantially increased continental megafauna richness and
TDWG-country-scale species richness within each conti-
nent: 62% of South American (mean SD, 37% 34%),
57% of North American (24% 37%), 33% of European
(36% 33%), 11% of Asian (17% 34%), and 11% of
African (10% 27%) megafauna are introduced. Introduced
megafauna comprise at least 75% of the megafauna assem-
blages of 56 of the 369 (15%) TDWG countries.
Strikingly, the entire continental megafauna assemblage
of Australia is composed of introduced species. Australia lost
all megafauna species during the Pleistocene extinctions,
yet has become home to eight introduced species in the
Anthropocene, including the Endangered banteng Bos javan-
icus , the world’s only population of wild dromedary camel,
the Vulnerable sambar deer Rusa unicolor , and the water
buff alo Bubalus bubalis , the descendant of the Endangered
water buff alo B. arnee. Wild donkeys Equus asinus , whose
progenitor, the African wild ass E. africanus is Critically
Endangered, and Endangered horses E. ferus caballus , have
also found refuge in Australia, as well as in North America,
South America, and Europe.
Bovidae (34)
Camelidae (3)
Cervidae (9)
Elephantidae (2)
Equidae (7)
Giraffidae (2)
Hippopotamidae (2)
Hominidae (2)
Rhinocerotidae (5)
Suidae (6)
Tapiridae (4)
Total (76)
Percent of family with introduced
populations by IUCN threat status
Least Concern Near−Threatened
Vulnerable Endangered
Critically Endangered Extinct
Figure 1. reatened megafauna species are fi nding refuge outside
their native ranges. Percentage of megafauna in each family with
introduced populations, colored by IUCN threat categories in their
native ranges. Number within parentheses indicates total number
of megafauna within each family.
Least Concern
Near Threatened
Critically Endangered
Number of introduced species
Decreasing Stable Increasing N/A
Figure 2. e number of introduced megafauna species by IUCN
(2017) threat status and population trends in their native ranges.
e majority (59%) of introduced megafauna are threatened or
have declining populations in their native ranges.
Oryx gazella
Cervus elaphus
Ovibos moschatus
Boselaphus tragocamelus
Bison bison
Hippopotamus amphibius
Rangifer tarandus
Elephas maximus
Bos javanicus*
Bubalus bubalis*
Equus caballus*
Equus asinus*
Camelus dromedarius*
Bos taurus*
Percent of total populations
Least Concern Near−Threatened
Vulnerable Endangered
Critically Endangered Extinct
Figure 3. Percent of global populations of megafauna that are
introduced. Color indicates IUCN (2017) status. Bars indicate
high and low estimates if multiple estimates were found. Includes
only species with known population sizes in native and non-native
* indicates post-domestic species.
Native megafauna richness
Introduced megafauna richness
All megafauna richness
Percent introduced
Figure 4. Contribution of introduced megafauna to TDWG-country species richness. (a) Native megafauna species richness (b) introduced
megafauna species richness, (c) all megafauna species richness, and (d) percent contribution of introduced species to TDWG-country
megafauna assemblages. Inter- and intra-continental introductions were included. Native richness was derived from IUCN (2017) species
distribution data. Introduced species distributions are available in Supplementary material Appendix 1 Data A1.
introduced megafauna in the Anthropocene, so that there
are currently more megafauna species per continent than
at the end of the Holocene. Introduced megafauna have
numerically replaced extinct species richness in Australia by
67%, in South America by 21%, in North America by 26%,
in Europe by 33%, in Asia by 15%, and in Africa by 31%
(Fig. 5, Table 1).
Megafauna are likely to have signifi cant functional
roles in their introduced ranges.  eir average body
masses ranges from 109 to 3270 kg (median 256 kg,
mean 526 kg, SD 697 kg) (Table 2), which is rep-
resentative of the native megafauna body mass distribu-
tion ranging from 100 to 3825 kg (median 238 kg,
mean 496 kg, SD 666 kg). Introduced megafauna are
primarily grazers (45% of species) or intermediate grazers
and browsers (41% of species), and three species (14%) are
primarily browsers (Table 1). Introduced megafauna are
adapted for habitats ranging from Arctic tundra (muskox
Ovibos moschatus ) to tropical forest (sambar deer) and
deserts (dromedary camels) (Table 1). Although there is
little known about the specifi c ecological functionalities
of several introduced megafauna, many introduced species
are known for unique traits, such as the ability to drink
brackish water and consume halophytic plants (dromedary
camel) or to survive without surface water (gemsbok Oryx
gazella ) (Table 2).
Introduced megafauna represent a signifi cant proportion of
the remaining taxonomic diversity of their functional group
and are themselves signifi cantly threatened in their historic
native ranges.  is raises the question of how to assign con-
servation value in an era of extinction and redistribution.
Conservation biology is a fi eld driven by a plurality of values,
which off er various visions at diff erent scales and times
(Sandbrook et al. 2011). Many current schools of thought
prioritize the conservation of species considered to be native
at the local and regional scale. However, given the ongoing
global extinction process, more research and dialogue is
needed to understand when these values may undermine
other conservation goals and values.
While many introduced populations were formerly
domesticated, they may still eff ectively represent their wild
relatives. Introduced populations of Endangered banteng
in northern Australia have maintained high genetic fi delity
Late Pleistocene losses of megafauna species (100% for
Australia, 89% for South America, 89% for North America,
53% for Europe, 41% for Asia, and 27% for Africa) and
Holocene losses (14% for Europe, 5% for Asia, and 3% for
Africa) were substantial. Following the Pleistocene, North
American species richness increased from 4 to 6 due to
immigration of wapiti Cervus canadensis and moose Alces
alces from Eurasia concurrent with the arrival of the fi rst
humans to the continent (Hundertmark et al. 2002, Meiri
et al. 2014). Reductions in species richness on all continents
since the Pleistocene have been counteracted by gains from
Africa Asia Europe North
America Australia
Epoch by continent
Number of megafauna species
Extinct Extirpated Immigrated
Survived Survived, threatened Introduced
Introduced, threatened
Figure 5. Megafauna species richness per epoch by continent.
Extinct indicates species that went extinct in the wild on all
continents; extirpated are species that survived elsewhere; immi-
grated are species that immigrated without human intervention;
introduced indicates species introduced by humans; introduced,
threatened are introduced species threatened in their native ranges;
survived are species that were still present into the following epoch;
survived, threatened are threatened native species (Supplementary
material Appendix 3 Table A2).
Table 1. Changes in megafauna species richness from the Pleistocene to the Anthropocene. In column 2, percent survived is the percent of
megafauna to survive the late Pleistocene extinctions; in column 3, percent lost/gained is the percent change in Holocene species richness
due to extinction/immigration during the Holocene; in column 4, percent replaced is the percent of all extinct megafauna richness (Pleistocene
and Holocene) to be numerically replaced by introductions in the Anthropocene.
* indicates natural immigration from Eurasia to North
America during the early Holocene.
Continent Pleistocene species richness
Holocene species richness
(percent survived)
Holocene extinctions/immigration
(percent lost/gained)
Anthropocene richness
(percent replaced)
Africa 44 32 (73%) 1 ( 3%) 35 (31%)
Asia 61 36 (59%) 2 ( 6%) 38 (14%)
Australia 12 0 (0%) N/A 8 (67%)
Europe 15 7 (47%) 1 ( 14%) 9 (33%)
North America 35 4 (11%) 2 ( 33%)
* 14 (26%)
South America 44 5 (11%) 0 (0%) 12 (18%)
Table 2. Functional traits of introduced megafauna. ABM is average body mass (Jones et al. 2009); foraging type is B is browser, G is grazer, and G/B are intermediate; habitats are derived from IUCN
Redlist species accounts IUCN (2017) Red List.
Species Common name ABM Type Habitat Known or potential unique ecological functions
Alces alces Moose 541 B Woodlands, tundra, montane forests Browse at heights up to 2 m, affecting stand height and canopy composition (Pastor et al.
Bison bison Bison 625 G Grasslands, open forests Create wallows that become ephemeral pools, serve as fi re breaks, and increase landscape
scale plant diversity (Knapp et al. 1999).
Bos javanicus Banteng 636 G/B Open dry forests
Bos taurus Cattle 613 G Numerous
Boselaphus tragocamelus Nilgai 182 G/B Open grasslands Open trails in dense shrubland, capable of jumping 2.5 m high, potentially sustaining seed/
nutrient dispersal in fenced landscapes (Leslie 2008).
Bubalus bubalis Water buffalo 919 G/B Moist grasslands, marshes Used for conservation grazing to maintain open water habitat for birds and fi sh (BBC News
Camelus dromedarius Dromedary camel 488 B Desert scrub Salt-tolerant (Root-Bernstein and Svenning 2016); large home ranges (Spencer et al. 2012), may
redistribute sodium (Doughty et al. 2016a).
Cervus elaphus Red deer 241 G/B Generalist
Connochaetes gnou Black wildebeest 157 G Short-grass grasslands
Elephas maximus Asian elephant 3270 G/B Tropics Ecological engineer in native range by dispersing large seeds and removing trees (Donlan et al.
Equus asinus Donkey 180 G/B Deserts Digs wells used by other species.
Equus caballus Horse 400 G Grasslands, open forests Feeds on coarse, abrasive grasses (Naundrup and Svenning 2015).
Hippopotamus amphibius Hippopotamus 1536 G Aquatic daytime refuge; grasslands Maintain grazing meadows, fertilize riparian systems (Bakker et al. 2016b), unstudied in
introduced range.
Hippotragus niger Sable antelope 236 G/B Woodland edges
Kobus ellipsiprymnus Waterbuck 204 G Savanna woodlands Riparian grazer, likely infl uences riparian vegetation and river geomorphology (Naiman and
Rogers 1997, IUCN 2017).
Oryx gazella Gemsbok 188 G Desert scrub, desert grassland Dig wells used by other species (Hamilton et al. 1977).
Ovibos moschatus Muskox 313 G Arctic tundra Few other herbivores adapted to extreme arctic environment (Schmidt et al. 2015).
Ovis ammon Argali 114 G Steep, rocky environments
Rangifer tarandus Reindeer 109 G/B Mountains, arctic tundra Grazing can alter arctic albedo, causing temperature reductions that may counteract climate
change (te Beest et al. 2016). Uniquely capable of digesting lichens (Palo 1993).
Rucervus duvaucelii Barasingha 171 G Forests, riparian grasslands Riparian grazer, likely infl uences riparian vegetation and river geomorphology (Naiman and
Rogers 1997, IUCN 2017).
Rusa unicolor Sambar 178 G/B Generalist
co-evolutionary history versus ecological context in deter-
mining species coexistence and ecosystem function (Wallach
et al. 2015).
Introduced megafauna vary in body mass considerably,
which infl uences their ability to open thickets and digest
coarse fi brous vegetation and thus their relation to plant
communities and other herbivores. Introduced megafauna
also possess unique functional adaptations that may be of
ecological signifi cance in their new ranges. For example,
introduced camels are capable of ingesting brackish water
and consuming halophytic plants (Root-Bernstein and
Svenning 2016), which in conjunction with their large
home ranges (Spencer et al. 2012) may contribute to the
megafaunal redistribution of terrestrial salts (Doughty et al.
2016a). Likewise, the ability of gemsbok Oryx gazella to
survive without surface water (Hamilton et al. 1977) likely
allows it to occupy novel niches in the North American
deserts in which it now lives.
ere is substantial and growing evidence that intro-
duced species can perform signifi cant and desirable eco-
logical roles (Schlaepfer et al. 2011). Bighorn sheep forage
more effi ciently, with less time invested in vigilance behav-
iors in mixed herds with introduced wild horses (Coates and
Schemnitz 1994). Giant tortoises introduced onto oceanic
islands as substitutes for extinct species are dispersing large-
seeded endemic plants and shaping plant communities
through grazing (Hansen et al. 2010). Intentional introduc-
tions of horses and cattle in the Oostvaardersplassen nature
reserve in the Netherlands have created Pleistocene-like
savanna conditions in a temperate deciduous forest envi-
ronment (Vera 2009). In North America and Australia, the
drying and constriction of desert springs and the extinc-
tion of several endemic fi sh populations was linked to
the removal of wild introduced megafauna whose grazing
appeared to maintain open-water habitat (Kodric-Brown
and Brown 2007).
Likewise, our own ongoing research is yielding simi-
larly surprising observations. For example, in the Sonoran
Desert of North America, wild donkeys ( burros , E. asi-
nus ) dig groundwater wells of more than a meter in depth
(Supplementary material Appendix 4 Movie A1).  ese wells
are common wherever groundwater approaches the surface,
have been recorded in use by more than thirty mammal and
bird species, and in certain conditions become nurseries for
riparian trees (Fig. 6). It is possible that by creating new water
sources across the landscape, maintaining access to receding
water-tables during droughts, and providing conditions ideal
for the germination of riparian trees, wild donkeys play a
facilitative role, one that may improve the resilience of these
arid ecosystems to climate change. Furthermore, given the
ubiquity of taxa whose contemporaries dig wells, such as
Proboscideans (Ramey et al. 2013) and other equids (Feh
et al. 2002) in the North American Pleistocene, it is likely
that introduced donkeys have restored a functionality lost
from these landscapes.
Unfortunately, little more is known about the ecological
functions of megafauna outside their native ranges because the
majority of studies are conducted on the premise that intro-
duced species are harmful and should be suppressed or eradi-
cated. Future research on the ecological functions of introduced
megafauna, under varying ecological contexts (e.g. predator
to their pre-domestic ancestors (Bradshaw et al. 2005).
Likewise, domesticated horses retain a substantial component
of the genetic diversity of extinct Holarctic horse lineages
(Lippold et al. 2011). Given that the closest wild relatives of
all six post-domestic megafauna are Endangered or extinct,
it appears that domestication has provided a crucial bridge
for certain species from the pre-pastoral wild landscapes of
the early Holocene to the post-industrial wild landscapes of
the Anthropocene.
Evolutionary and ecological change has also been witnessed
in post-domestic populations. Wild goats Capra aegragus on
Aldabra Atoll regularly drink saltwater when freshwater is
absent (Burke 1990). Wild sheep Ovis aries show higher
resistance to local parasites than sympatric domestic sheep.
Wild Ossabaw island pigs Sus scrofa have unique lipid struc-
tures (Van Vuren and Hedrick 1989). Wild cattle in Mexico
do not linger in riparian areas like their sympatric domestic
cousins due to altered predation threats (Hernandez et al.
1999). Native Torresian crows Corvus orru appear to have
developed a mutualistic grooming behavior on introduced
banteng in Australia (Bradshaw and White 2006).
Like all herbivores, introduced megafauna can exert
strong grazing or browsing pressure to the detriment of
other species, most notably where apex predators are extir-
pated or continue to be persecuted (Wallach et al. 2010).
Unfortunately, much of the research to document these
eff ects has ignored the ecological context of predator con-
trol, which is to ignore an important explanatory variable
for the density-dependent eff ects of all herbivores. Indeed,
wild horses in the United States may be limited by mountain
lions (Turner and Morrison 2001) and dingoes appear to
suppress populations of wild donkeys in Australia (Wallach
et al. 2010).  e potential to infl uence the ecologies of intro-
duced megafauna by protecting or restoring large predators
is an important topic for further research.
In the Pleistocene, the ecological infl uences of herbivo-
rous megafauna on disturbance regimes, seed dispersal,
nutrient cycling, and community structure were ubiquitous.
Introduced megafauna have potentially augmented this lost
functional and taxonomic diversity across most continents,
particularly in those regions most depleted: Australia, North
America, and South America (Fig. 4). Asia and Africa have
retained many Pleistocene megafauna and have fewer intro-
duced species. Several of these introductions restore taxo-
nomic analogues to extinct Pleistocene species. For example,
introduced donkeys are morphologically similar to conge-
neric extinct North American and South American stilt-
legged horses, and the modern wild horse is the same species
as the horse of the Holarctic Pleistocene (Weinstock et al.
e late Pleistocene extinctions in Australia included all
megafauna and many browsing herbivores, the loss of which
appears to have led to increased fi re frequency and altered
plant community structure (Miller et al. 2005, Rule et al.
2012). Introduced megafauna, especially browsers such as
dromedary camels, may reverse these ecological state shifts.
However, determining how introductions of taxonomically
dissimilar species restore or add new functionalities within
insular ecosystems (there are no surviving taxonomic ana-
logues to Australia s Pleistocene marsupial megafauna)
requires further research into the relative importance of
and without potential predators in the novel ecosystems of
the Anthropocene will be essential in reconciling the con-
cerns of local managers with global conservation eff orts and
will bring new attention to the emerging eco-evolutionary
trajectories of these populations.
Acknowledgements We thank M. Sluk for his research assistance,
and J. Stromberg, F. Horgan, C. Sandom, V. K. Harris, and two
anonymous reviewers for helpful feedback on earlier drafts.
Confl icts of interest e authors declare no confl icts of interest.
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... The growing evidence that novel ecosystems are now the norm, not the exception (Dornelas et al., 2014;Russell & Kueffer, 2019), suggests that the traditional approach is obsolete, and that a more flexible methodology is needed in which conservation management focuses on functional integrity rather than particular species (Barnosky et al., 2017;Hobbs et al., 2009;Kueffer & Kaiser-Bunbury, 2014). Such arguments emphasize the positive contributions that alien species can make to regional species richness, to ecosystem services and resilience, and to delivering conservation and restoration goals (Ewel & Putz, 2004;Goodenough, 2010;Guiasu, 2016;Lundgren et al., 2018;Schlaepfer, 2018b;Schlaepfer et al., 2011;Tassin & Kull, 2015;Thomas, 2013). The same reasons that make some alien species so successful (adaptability, vigor, resilience) render them potentially beneficial in an increasingly human-dominated world (G. ...
... Such arguments underlie numerous calls to abandon the purist pursuit of nativeness in favor of pragmatic realism Holl, 2018;Lundgren et al., 2018;Macdonald et al., 2007;Switzer & Angeli, 2016;Thomas, 2017;Warren, , 2011 -to replace 'dogma about native and aliens [with] a sense of proportion and common sense' (Smout, 2014, p. 16). Interestingly, Elton (1958, p. 145) himself adopted a notably more pragmatic approach than the purism enshrined in many of today's conservation policies, believing that the goal of maximizing ecological variety could include aliens, and arguing for 'coexistence between man and nature, even if it has to be a modified kind of man and a modified kind of nature'. ...
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Classifying species as ‘native’ or ‘alien’ carries prescriptive force in the valuation and management of ‘nature’. But the classification itself and its application are contested, raising philosophical and geographical questions about place, space, rights, identity and belonging. This paper discusses leading critiques of the native/alien paradigm, including its conceptual fluidity, dichotomous rigidity and ethical difficulties, as well as the incendiary charge of xenophobia. It argues that valorizing ‘native nature’ as inherently the ‘best nature’ is not only obsolete but impracticable in the Anthropocene, and that the pre-eminence of biogeographic origins should be replaced with a pragmatic focus on species’ behaviour.
... Taxa substitution aims to restore essential functions such as seed dispersal, grazing and bioturbation using extant species that are functionally equivalent to those lost by extinction or extirpation (Griffiths et al. 2011). For example, de-extinction through artificial selection is being employed to reconstitute ancestral phenotypes and ecological roles in domesticated cattle and horses (Stokstad 2015, Lundgren et al. 2018). However, in most situations, domesticated descendants are unlikely to exist, necessitating a different solution such as taxa substitution or ecological replacement. ...
In recent decades, anthropogenic and natural disturbances have increased in rate and intensity around the world, leaving few ecosystems unaffected. As a result of the interactions among these multiple disturbances, many biological communities now occur in a degraded state as collections of fragmented ecological pieces. Restoration strategies are traditionally driven by assumptions that a community or ecosystem can be restored back to a pre-disturbance state through ecological remediation. Yet despite our best efforts, attempts to restore fragmented communities are often unsuccessful. One explanation, the humpty-dumpty effect, suggests that once a community is disassembled , it is difficult to reassemble it even in the presence of all the original pieces. This hypothesis, while potentially useful, often fails to incorporate the multitude of other critical mechanisms that affect our abilities to put fragmented communities back together. Here, we extend the original humpty-dumpty analogy to incorporate eco-evolutionary changes that can hinder successful restoration. A systematic literature review uncovered few studies that have explicitly considered how the original humpty-dumpty effect has affected restoration success in the 30 years since its inception. Using case studies, we demonstrate how the application of our extended eco-evolutionary humpty-dumpty framework may determine the success of restoration actions via ecological and evolutionary changes in fragments of communities. Lastly, given continued anthropogenic disturbances and projected climatic changes, we make five recommendations to facilitate more successful restoration efforts given our revised eco-evolutionary humpty-dumpty effects framework. These guidelines, combined with clearly defined management goals are aimed at both keeping ecological communities as intact as possible while ensuring that future ecosystem restorations might more successfully put the ecological community pieces back together.
... In the Anthropocene, humans play a central role in shaping geology and ecology (Crutzen and Stoermer 2000, Steffen et al. 2016, Lee-Yaw et al. 2 2019, Shoshitaishvili 2021. The Anthropocene theory suggests that human activities such as species introductions, artificial transplantations, trade and travel have facilitated breaching of natural biogeographic barriers, which results in species establishment in locations far away from their native range (Helmus et al. 2014, Capinha et al. 2015, Ellis 2015, Lundgren et al. 2018, Lee-Yaw et al. 2019. Ultimately, the 'classical' biogeographic patterns break down and novel biogeographic patterns emerge (Darling and Carlton 2018, Bernardo-Madrid et al. 2019, Sales et al. 2019. ...
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Introduction of species by humans breaks down biogeographic boundaries and results in the homogenization of species composition, yet empirical tests of this impact in marine forest ecosystems are still scarce. Large-scale planting aimed at reversing losses of mangroves has been the dominant strategy for mangrove restoration adopted by many organizations in the past decades, but there is a lack of quantitative understanding of the impacts of such large-scale plantings on mangrove biogeography. Here we used data collected before and after large-scale planting to compare the species richness and compositional similarities among 72 mangrove sites over a biogeographic scale (18–28°N) in China. After the large-scale planting, 15 of the mangrove species spread toward the higher latitudes, reflecting the geographical barriers of the mangrove plants have been broken. Local species richness of mangrove increased by 44.82% and biogeographic compositional similarity of mangroves increased by 13.33%, reflecting large-scale introduction and planting increase local diversity of mangrove but enhance biological homogenization. The dispersal limitation of mangrove communities reduced by 11.1%, which indicates that the community assemblage process of mangrove changed obviously. Worryingly, two alien species, Sonneratia apetala and Laguncularia racemosa, have dispersal across the biogeographic scale studied, reflecting an increase in the risk of biogeographic invasion. It is expected that biological homogeneity and species invasion will further influence the functional biogeography of mangroves. Our results highlight that mangrove biogeography is defined by human activities in the Anthropocene.
... "Rewilding" as a concept has had much discussion since it was introduced and means different things to different people (Lundgren et al. 2018;Pettorelli et al. 2019;Gordon et al. 2021). Some authors, e.g. ...
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This paper deals with reflections that arose after observing prehistoric rock engravings at different locations in Namibia. These observations stimulated comparative considerations with focus on southern Africa and central Europe. Similar to the Aurignacian rock art of European origin, the most common motifs in the Namibian rock engravings are large animals. While in Europe, the species that served as a blueprint for the illustration of Aurignacian rock art have mostly disappeared, the megafauna illustrated on the rock engravings in Namibia can still be found in the immediate vicinity of the rock art. Against this background, we discuss and further develop a comparative regional approach. We reconstruct and evaluate the suitability of African savannas and still-existing mega-fauna communities as an appropriate reference-frame for natural European grassland systems and extinct associated warm-adapted megafauna (Eemian Interglacial megafauna). Special attention is laid on the unique situation in Africa in the light of a global extinction wave of megafauna following increasing human activity in the Late Quaternary. This leads us to discuss the use of domesticated ungulates as surrogate taxa to fulfill ecosystem functions in Europe as part of concepts termed "rewilding" or "naturalistic grazing". After critically examining these concepts, we conclude that using domesticated forms as representatives of extinct or locally disappeared species in Europe has its justification to some extent. If, however, the naturally occurring megaherbivore community still exists (Africa), these naturally occurring species should be given priority due to their organismic abilities and limitations adapted to the harsh conditions in their specific environment. Finally, we discuss the application of (transboundary) protected areas as effective instruments to mitigate human-wildlife conflicts. A holistic approach, including nature conservation and preservation of cultural achievements (domesticated forms, grazing systems), appears promising for the effective protection of the natural African savanna ecosystems with their unique fauna elements, as illustrated in rock engravings that inspired us to write this paper.
... For instance, the changes in primary productivity, kelp export, and spore dispersal would have reduced both the export and sequestration of primary production, while sea cow-mediated predator-prey dynamics and nutrient availability (as particulate organic matter) would have altered the abundance of important fish and invertebrate species. Thus, the changes ascribed to more recent and well-described impacts such as hunting of marine mammals for pelts Kenyon, 1969), industrial fishing Steneck et al., 2013), and climate change The sea cow is one of many examples where a valuable species has been lost, and the restoration of trophic interactions and ecosystem functions could help maintain and improve desired ecosystem states (Corlett, 2016;Donlan et al., 2006;Lundgren et al., 2018;Svenning et al., 2016). Approaches to functional restoration have included rewilding and species substitutions (Griffiths et al., 2013;Guyton et al., 2020;Zimov et al., 1995), often -but not always -with positive results (Ehrlich & Mooney, 1983;Seddon, Griffiths et al., 2014). ...
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The global decline of megafauna is believed to have had significant and widespread ecological impacts. One such extinction of likely important consequence is the 18th century extinction of the Steller’s sea cow (Hydrodamalis gigas); however, little has been written about how the loss of this megaherbivore may have impacted coastal ecosystem dynamics. Drawing on historical evidence, sea cow biology, kelp forest ecology, and the ecology of extant sirenians, we propose several discrete hypotheses about the effects Steller’s sea cows may have had on kelp forest dynamics of the North Pacific. North Pacific Ocean. Pre‐1760s. Steller’s sea cow (Hydrodamalis gigas). The evidence we review suggests that Steller’s sea cows exerted substantial direct and indirect influences on kelp forests, likely affecting the physical ecosystem structure, productivity, nutrient cycling, species interactions, and export of nutrients to surrounding ecosystems. This suggests that kelp forest dynamics and resilience were already significantly altered prior to the influence of more recent and well‐known stressors, such as industrial fishing and climate change, and illustrates the important ecological roles that are lost with megafaunal extinction.
... Under certain situations experimental translocations, whether inside or outside of historical ranges, may be the only way to expand our knowledge of a species' biology and determine whether a particular habitat is suitable. In some cases, a functional role within the ecosystem must be filled for ecological functionality to be restored (Lundgren et al., 2018). Soft releases into fenced areas can reduce risk and can be followed by gradual releases into the wider habitat. ...
Taxonomic and geographic biases in ecological research are widely recognised. In addition, information bias within a species can impact our understanding of their biology. This can lead to an underestimation of potential intra- or inter-population level variation and plasticity, and incomplete inferences about species response curves across environmental gradients. The consequences of these ‘species stereotypes’ are misestimation of the potential niche and narrow, potentially biased, views of habitat and diet preferences. For example, species may be characterised as ecologically static, or a habitat, diet, or prey ‘specialist’. Several factors can contribute to the formation of a ‘stereotype’, including a focus on extant populations, or a subset of them, that only partially represent the full historical distribution of a species, and an emphasis on species interactions derived from a small number of potential communities. Such species stereotypes are likely widespread and impact on many taxa. These misconceptions can have knock-on effects for conservation programmes and lead to ineffective or harmful conservation interventions such as actively managing species in marginal habitats, not identifying key threats and incorrect predictions of vulnerability to environmental change. Recognising biases is vital to addressing these potential problems and providing accurate information for conservation programmes. Biases can be identified by evaluating historical distributions, translocations within historical distributions, developing mechanistic distribution models and assessing traditional ecological knowledge. We suggest that explicit assessment of biases and potential stereotypes are included in red listing or species assessments, biodiversity action plans, and protected area network design and evaluation.
... Donkeys have also been recognized as important elements of ecological landscapes, and they have a role to play in the natural management of wild ecosystems. For example, donkeys act as seed-dispersal agents for a range of plants, including Prosopis, a genus of tropical or subtropical branching shrubs or trees widespread in arid and semi-arid zones of the Americas with vast economic value (Baes et al., 2002;Sánchez de la Vega & Godínez-Alvarez, 2010;Lundgren et al., 2018). ...
Donkeys have a long history in the development of human societies. Typically referred to as a beast of burden, traditional uses for donkeys have included the transportation of goods and people, use in agricultural and forestry activities, to access water, and provide citizens in low- and middle-income countries a means of making an income for communities. However, the rise of mechanization, the development of modern farming techniques, and the increasing availability of motorized vehicles have led to donkeys and mules becoming redundant from traditional roles in many parts of the world. We provide examples of where donkeys have successfully transitioned from traditional roles to new, non-traditional roles in Europe and North America, and demonstrate that, although the roles and use of donkeys and mules are changing in a rapidly developing world, we can learn lessons from the past and apply them to current challenges. As the need for working equids declines in transport and agriculture, they still hold great value for recreational, therapeutic, and environmentally friendly methods of animal traction.
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Introduced large herbivores have partly filled ecological gaps formed in the late Pleistocene, when many of the Earth's megafauna were driven extinct. However, extant predators are generally considered incapable of exerting top-down influences on introduced megafauna, leading to unusually strong disturbance and herbivory relative to native herbivores. We report on the first documented predation of juvenile feral donkeys Equus africanus asinus by cougars Puma concolor in the Mojave and Sonoran Deserts of North America. We then investigated how cougar predation corresponds with differences in feral donkey behaviour and associated effects on desert wetlands. Focusing on a feral donkey population in the Death Valley National Park, we used camera traps and vegetation surveys to compare donkey activity patterns and impacts between wetlands with and without cougar predation. Donkeys were primarily diurnal at wetlands with cougar predation, thereby avoiding cougars. However, donkeys were active throughout the day and night at sites without predation. Donkeys were ~87% less active (measured as hours of activity a day) at wetlands with predation (p < 0.0001). Sites with predation had reduced donkey disturbance and herbivory, including ~46% fewer access trails, 43% less trampled bare ground and 192% more canopy cover (PERMANOVA, R2 = 0.22, p = 0.0003). Our study is the first to reveal a trophic cascade involving cougars, feral equids and vegetation. Cougar predation appears to rewire an ancient food web, with diverse implications for modern ecosystems. Our results suggest that protecting apex predators could have important implications for the ecological effects of introduced megafauna.
Trophic rewilding is proposed as an effective approach to tackle biodiversity loss by restoring ecosystem dynamics through the reintroduction of large-bodied animals. Currently, evidence on the effectiveness of reintroduction programs is sparse and difficult to generalize. To better understand the ecological consequences of trophic rewilding, we simulated the extinction and reintroduction of large-bodied mammals under four distinct environmental conditions. We found that the removal of large-bodied mammals leads to large cascading effects mainly expressed by increases in smaller-bodied herbivores and the release of mesopredators. Our results further suggest that reintroducing extinct large-bodied mammals can largely restore shifts in ecosystem structure, closely resembling the baseline ecosystem conditions. However, the extent to which the ecosystem’s state resembles the original ecosystem is heavily dependent on the reintroduction strategy (only herbivores and omnivores vs. all large-bodied mammals) and timing, as well as local environmental conditions.
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Resolving the relative contributions of top-down versus bottom-up drivers of vegetation dynamics is a major challenge in drylands. In the coming decades, growing livestock populations and shifts in water availability will simultaneously impact many arid systems, but a lack of empirical data on plant responses to these pressures limits understanding of how plants will respond. Here, we combine ground and drone observations from an herbivore exclosure experiment to identify ungulate visitation patterns and their impacts on the cover and melon production of !nara ( Acanthosicyos horridus ), a large, long-lived desert plant in the hyper-arid Namib Desert. !Nara are of key ecological, social, and economic importance to Namib ecosystems and to the local Topnaar people. At our study site, we find that among native and domestic herbivores, free-ranging donkeys have the largest impact on !nara cover and melon production. !Nara cover was negatively affected by herbivores close to the desert-ephemeral river ecotone during a dry period, whereas !nara cover increased on all plants across the landscape during a wetter period, regardless of herbivore access. !Nara near the river channel and those protected from herbivores had more mature melons, particularly during the wetter period. At this site, the potential for conflict between Topnaar !nara melon harvesting and pastoral practices varies with a plant’s distance from the river and prevailing abiotic conditions. This work advances monitoring approaches and adds empirical support to the understanding that top-down and bottom-up regulation of plant dynamics varies with spatiotemporal context, even within landscapes.
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Large vertebrates are strong interactors in food webs, yet they were lost from most ecosystems after the dispersal of modern humans from Africa and Eurasia. We call for restoration of missing ecological functions and evolutionary potential of lost North American megafauna using extant conspecifics and related taxa. We refer to this restoration as Pleistocene rewilding; it is conceived as carefully managed ecosystem manipulations whereby costs and benefits are objectively addressed on a case‐by‐case and locality‐by‐locality basis. Pleistocene rewilding would deliberately promote large, long‐lived species over pest and weed assemblages, facilitate the persistence and ecological effectiveness of megafauna on a global scale, and broaden the underlying premise of conservation from managing extinction to encompass restoring ecological and evolutionary processes. Pleistocene rewilding can begin immediately with species such as Bolson tortoises and feral horses and continue through the coming decades with elephants and Holarctic lions. Our exemplar taxa would contribute biological, economic, and cultural benefits to North America. Owners of large tracts of private land in the central and western United States could be the first to implement this restoration. Risks of Pleistocene rewilding include the possibility of altered disease ecology and associated human health implications, as well as unexpected ecological and sociopolitical consequences of reintroductions. Establishment of programs to monitor suites of species interactions and their consequences for biodiversity and ecosystem health will be a significant challenge. Secure fencing would be a major economic cost, and social challenges will include acceptance of predation as an overriding natural process and the incorporation of pre‐Columbian ecological frameworks into conservation strategies.
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In our recent perspective article, we noted that most (approximately 0 percent) terrestrial large carnivore and large herbivore species are now threatened with extinction, and we offered a 13-point declaration designed to promote and guide actions to save these iconic mammalian megafauna (Ripple et al. 2016). Some may worry that a focus on saving megafauna might undermine efforts to conserve biodiversity more broadly. We believe that all dimensions of biodiversity are important and that efforts to conserve megafauna are not in themselves sufficient to halt the dispiriting trends of species and population losses in recent decades. From 1970 to 2012, a recent global analysis showed a 58 percent overall decline in vertebrate population abundance (WWF 2016). Bold and varied approaches are necessary to conserve what remains of Earth’s biodiversity, and our declaration in no way disputes the value of specific conservation initiatives targeting other taxa. Indeed, the evidence is clear that without massively scaling up conservation efforts for all species, we will fail to achieve internationally agreed-upon targets for biodiversity (Tittensor et al. 2014).
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Previous studies have shown that climate warming is causing shrub cover to increase at high latitudes. Increased shrub cover generally lowers surface albedo, which results in higher energy absorption and further warming. In parts of Fennoscandia herbivory is known to control vegetation height and density, thus preventing this positive feedback. Here, we combine field measurements of albedo, herbivory and vegetation characteristics in four topographically-defined vegetation types of varying shrub height and density with land surface modeling (JULES) to investigate if reindeer grazing can influence the energy balance of an arctic tundra via altered summer albedo. We find that reindeer grazing reduces shrub height and abundance, and increases summer albedo in Betula nana-dominated heath vegetation and Salix glauca-dominated willow depressions. Model results show associated lower net radiation, and latent and sensible heat fluxes in heavily-grazed sites in all shrub-dominated vegetation types. Our results also suggest that the structural shift from graminoid to shrub tundra drives the difference in summer albedo, rather than shifts from dwarf-shrub to tall-shrub tundra. We show that reindeer grazing has a potential cooling effect on climate by increasing summer albedo and decreasing net radiation. This highlights the importance of mammalian herbivores for the earth system beyond their local grazing impacts. However, the strong effects of reindeer grazing on albedo presented here are detected in an area with high reindeer densities. The importance of these processes across the whole range of reindeer densities found in the arctic tundra needs to be further evaluated.
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From the late Pleistocene to the Holocene and now the so-called Anthropocene, humans have been driving an ongoing series of species declines and extinctions (Dirzo et al. 2014). Large-bodied mammals are typically at a higher risk of extinction than smaller ones (Cardillo et al. 2005). However, in some circumstances, terrestrial megafauna populations have been able to recover some of their lost numbers because of strong conservation and political commitment, as well as human cultural changes (Chapron et al. 2014). Indeed, many would be in considerably worse predicaments in the absence of conservation action (Hoffmann et al. 2015). Nevertheless, most mammalian megafauna face dramatic range contractions and population declines. In fact, 59% of the world's largest carnivores (more than or equal to 15 kilograms, n = 27) and 60% of the world's largest herbivores (more than or equal to 100 kilograms, n = 74) are classified as threatened with extinction on the International Union for the Conservation of Nature (IUCN) Red List (supplemental tables S1 and S2). This situation is particularly dire in sub-Saharan Africa and Southeast Asia, home to the greatest diversity of extant megafauna (figure 1). Species at risk of extinction include some of the world's most iconic animals—such as gorillas, rhinos, and big cats (figure 2 top row)—and, unfortunately, they are vanishing just as science is discovering their essential ecological roles (Estes et al. 2011). Here, our objectives are to raise awareness of how these megafauna are imperiled (species in tables S1 and S2) and to stimulate broad interest in developing specific recommendations and concerted action to conserve them
Winner in the Scholarly Reference section of the 2004 Australian Awards for Excellence in Educational Publishing. Introduced Mammals of the World provides a concise and extensive source of information on the range of introductions of mammals conducted by humans, and an indication as to which have resulted in adverse outcomes. It provides a very valuable tool by which scientists can assess future potential introductions (or re-introductions) to avoid costly mistakes. It also provides tangible proof of the need for political decision makers to consider good advice and make wise and cautious decisions. Introduced Mammals of the World also provides a comprehensive reference to students of ecological systems management and biological conservation. This book is a companion volume to Introduced Birds of the World, by the same author, published in 1981, and which remains the premier text of its kind in the world more than twenty years after it was published. Introduced Mammals of the World provides the most comprehensive account of the movement of mammals around the world providing details on the date(s) of introduction, the person/agency responsible, the source populations, the location(s) of release, the fate of the introductions, and the impact if known, for over 300 species of mammal.
Desert springs are fragile ecosystems that often harbor endemic species of fishes and other taxa. Historically, these springs experienced major disturbances from Pleistocene megafauna, aboriginal humans, and livestock. However, management practices to preserve and restore spring ecosystems and biota have led to the removal of livestock. We document changes in spring habitats and extinctions of fish populations due to management practices at two spring reserves: Ash Meadows in the southwestern United States and Dalhousie in central Australia. After springs were fenced and livestock removed, these ecosystems experienced increases in riparian vegetation, reduction of open-water habitat, and extinction of fish populations. Despite manual removal of vegetation to maintain open-water habitat, at least one pupfish population went extinct in Ash Meadows, and 18 populations, representing four of the five species native to desert springs in the Dalhousie reserve, also went extinct. To maintain the diversity of aquatic habitats and endemic biota, management of small desert springs must include substantial disturbance.
As invasive species management becomes more ambitious in scope and scale, projects are increasingly challenged by disputes and conflicts among people, which can produce undesirable environmental and social outcomes. Here, we examine when and how conflicts have arisen from invasive species management, and consider why some management approaches may be more prone to conflict than others. Insufficient appreciation of sociopolitical context, non-existent or perfunctory public and community engagement, and unidirectional communications can all foster “destructive” conflict. We propose that approaches to conflict in invasive species management might be transformed by anticipating disagreements, attending more carefully to the social-ecological contexts of management, adopting more inclusive engagement mechanisms, and fostering more open, responsive communication. Conflicts may be unavoidable, but they can be anticipated and need not be destructive.
The wild camelids wild Bactrian camel (Camelus ferus), guanaco (Lama guanicoe), and vicuña (Vicugna vicugna) as well as their domestic relatives llama (Lama glama), alpaca (Vicugna pacos), dromedary (Camelus dromedarius) and domestic Bactrian camel (Camelus bactrianus) may be good candidates for rewilding, either as proxy species for extinct camelids or other herbivores, or as reintroductions to their former ranges. Camels were among the first species recommended for Pleistocene rewilding. Camelids have been abundant and widely distributed since the mid-Cenozoic and were among the first species recommended for Pleistocene rewilding. They show a range of adaptations to dry and marginal habitats, and have been found in deserts, grasslands and savannas throughout paleohistory. Camelids have also developed close relationships with pastoralist and farming cultures wherever they occur. We review the evolutionary and paleoecological history of extinct and extant camelids, and then discuss their potential ecological roles within rewilding projects for deserts, grasslands and savannas. The functional ecosystem ecology of camelids has not been well researched, and we highlight functions that camelids are likely to have, but which require further study. We also discuss alternative rewilding-inspired land-use models given the close relationships between humans and some camelid species.