Humans have altered terrestrial ecosystems for millennia 1, yet wilderness areas still remain as vital refugia where natural ecological and evolutionary processes operate with minimal human ...disturbance 2–4, underpinning key regional- and planetary-scale functions 5, 6. Despite the myriad values of wilderness areas—as critical strongholds for endangered biodiversity 7, for carbon storage and sequestration 8, for buffering and regulating local climates 9, and for supporting many of the world’s most politically and economically marginalized communities 10—they are almost entirely ignored in multilateral environmental agreements. This is because they are assumed to be relatively free from threatening processes and therefore are not a priority for conservation efforts 11, 12. Here we challenge this assertion using new comparable maps of global wilderness following methods established in the original “last of the wild” analysis 13 to examine the change in extent since the early 1990s. We demonstrate alarming losses comprising one-tenth (3.3 million km2) of global wilderness areas over the last two decades, particularly in the Amazon (30%) and central Africa (14%). We assess increases in the protection of wilderness over the same time frame and show that these efforts are failing to keep pace with the rate of wilderness loss, which is nearly double the rate of protection. Our findings underscore an immediate need for international policies to recognize the vital values of wilderness and the unprecedented threats they face and to underscore urgent large-scale, multifaceted actions needed to maintain them.
•Globally important wilderness areas are ignored in conservation policy•We reveal that extensive losses of wilderness have occurred in the last two decades•Efforts aimed at protecting wilderness areas are failing to keep pace with its loss•International policy must recognize the actions needed to maintain wilderness areas
Watson et al. discover that the Earth’s wilderness areas are disappearing at a rate that has significantly outpaced their protection over the past two decades. Despite their ecological, climatological, and cultural importance, wilderness areas are ignored in multilateral environmental agreements, highlighting the need for urgent global policy attention.
Temperature is a major environmental cue affecting plant growth and development. Plants often experience higher temperatures in the context of a 24 h day-night cycle, with temperatures peaking in the ...middle of the day. Here, we find that the transcript encoding the bHLH transcription factor PIF7 undergoes a direct increase in translation in response to warmer temperature. Diurnal expression of PIF7 transcript gates this response, allowing PIF7 protein to quickly accumulate in response to warm daytime temperature. Enhanced PIF7 protein levels directly activate the thermomorphogenesis pathway by inducing the transcription of key genes such as the auxin biosynthetic gene YUCCA8, and are necessary for thermomorphogenesis to occur under warm cycling daytime temperatures. The temperature-dependent translational enhancement of PIF7 messenger RNA is mediated by the formation of an RNA hairpin within its 5' untranslated region, which adopts an alternative conformation at higher temperature, leading to increased protein synthesis. We identified similar hairpin sequences that control translation in additional transcripts including WRKY22 and the key heat shock regulator HSFA2, suggesting that this is a conserved mechanism enabling plants to respond and adapt rapidly to high temperatures.
Predicting how species respond to human pressure is essential to anticipate their decline and identify appropriate conservation strategies. Both human pressure and extinction risk change over time, ...but their inter-relationship is rarely considered in extinction risk modelling. Here we measure the relationship between the change in terrestrial human footprint (HFP)-representing cumulative human pressure on the environment-and the change in extinction risk of the world's terrestrial mammals. We find the values of HFP across space, and its change over time, are significantly correlated to trends in species extinction risk, with higher predictive importance than environmental or life-history variables. The anthropogenic conversion of areas with low pressure values (HFP < 3 out of 50) is the most significant predictor of change in extinction risk, but there are biogeographical variations. Our framework, calibrated on past extinction risk trends, can be used to predict the impact of increasing human pressure on biodiversity.
Understanding changes in species distributions is essential to disentangle the mechanisms that drive their responses to anthropogenic habitat modification. Here we analyse the past (1970s) and ...current (2017) distribution of 204 species of terrestrial non-volant mammals to identify drivers of recent contraction and expansion in their range. We find 106 species lost part of their past range, and 40 of them declined by >50%. The key correlates of this contraction are large body mass, increase in air temperature, loss of natural land, and high human population density. At the same time, 44 species have some expansion in their range, which correlates with small body size, generalist diet, and high reproductive rates. Our findings clearly show that human activity and life history interact to influence range changes in mammals. While the former plays a major role in determining contraction in species' distribution, the latter is important for both contraction and expansion.
Governments have agreed to expand the global protected area network from 13% to 17% of the world's land surface by 2020 (Aichi target 11) and to prevent the further loss of known threatened species ...(Aichi target 12). These targets are interdependent, as protected areas can stem biodiversity loss when strategically located and effectively managed. However, the global protected area estate is currently biased toward locations that are cheap to protect and away from important areas for biodiversity. Here we use data on the distribution of protected areas and threatened terrestrial birds, mammals, and amphibians to assess current and possible future coverage of these species under the convention. We discover that 17% of the 4,118 threatened vertebrates are not found in a single protected area and that fully 85% are not adequately covered (i.e., to a level consistent with their likely persistence). Using systematic conservation planning, we show that expanding protected areas to reach 17% coverage by protecting the cheapest land, even if ecoregionally representative, would increase the number of threatened vertebrates covered by only 6%. However, the nonlinear relationship between the cost of acquiring land and species coverage means that fivefold more threatened vertebrates could be adequately covered for only 1.5 times the cost of the cheapest solution, if cost efficiency and threatened vertebrates are both incorporated into protected area decision making. These results are robust to known errors in the vertebrate range maps. The Convention on Biological Diversity targets may stimulate major expansion of the global protected area estate. If this expansion is to secure a future for imperiled species, new protected areas must be sited more strategically than is presently the case.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Increased efforts are required to prevent further losses to terrestrial biodiversity and the ecosystem services that it provides
. Ambitious targets have been proposed, such as reversing the ...declining trends in biodiversity
; however, just feeding the growing human population will make this a challenge
. Here we use an ensemble of land-use and biodiversity models to assess whether-and how-humanity can reverse the declines in terrestrial biodiversity caused by habitat conversion, which is a major threat to biodiversity
. We show that immediate efforts, consistent with the broader sustainability agenda but of unprecedented ambition and coordination, could enable the provision of food for the growing human population while reversing the global terrestrial biodiversity trends caused by habitat conversion. If we decide to increase the extent of land under conservation management, restore degraded land and generalize landscape-level conservation planning, biodiversity trends from habitat conversion could become positive by the mid-twenty-first century on average across models (confidence interval, 2042-2061), but this was not the case for all models. Food prices could increase and, on average across models, almost half (confidence interval, 34-50%) of the future biodiversity losses could not be avoided. However, additionally tackling the drivers of land-use change could avoid conflict with affordable food provision and reduces the environmental effects of the food-provision system. Through further sustainable intensification and trade, reduced food waste and more plant-based human diets, more than two thirds of future biodiversity losses are avoided and the biodiversity trends from habitat conversion are reversed by 2050 for almost all of the models. Although limiting further loss will remain challenging in several biodiversity-rich regions, and other threats-such as climate change-must be addressed to truly reverse the declines in biodiversity, our results show that ambitious conservation efforts and food system transformation are central to an effective post-2020 biodiversity strategy.
Habitat loss is the leading cause of the global decline in biodiversity, but the influence of human pressure within the matrix surrounding habitat fragments remains poorly understood. Here, we ...measure the relationship between fragmentation (the degree of fragmentation and the degree of patch isolation), matrix condition (measured as the extent of high human footprint levels), and the change in extinction risk of 4,426 terrestrial mammals. We find that the degree of fragmentation is strongly associated with changes in extinction risk, with higher predictive importance than life-history traits and human pressure variables. Importantly, we discover that fragmentation and the matrix condition are stronger predictors of risk than habitat loss and habitat amount. Moreover, the importance of fragmentation increases with an increasing deterioration of the matrix condition. These findings suggest that restoration of the habitat matrix may be an important conservation action for mitigating the negative effects of fragmentation on biodiversity.
Abstract
Pulsar timing arrays aim to detect nanohertz-frequency gravitational waves (GWs). A background of GWs modulates pulsar arrival times and manifests as a stochastic process, common to all ...pulsars, with a signature spatial correlation. Here we describe a search for an isotropic stochastic gravitational-wave background (GWB) using observations of 30 millisecond pulsars from the third data release of the Parkes Pulsar Timing Array (PPTA), which spans 18 yr. Using current Bayesian inference techniques we recover and characterize a common-spectrum noise process. Represented as a strain spectrum
h
c
=
A
(
f
/
1
yr
−
1
)
α
, we measure
A
=
3.1
−
0.9
+
1.3
×
10
−
15
and
α
= −0.45 ± 0.20, respectively (median and 68% credible interval). For a spectral index of
α
= −2/3, corresponding to an isotropic background of GWs radiated by inspiraling supermassive black hole binaries, we recover an amplitude of
A
=
2.04
−
0.22
+
0.25
×
10
−
15
. However, we demonstrate that the apparent signal strength is time-dependent, as the first half of our data set can be used to place an upper limit on
A
that is in tension with the inferred common-spectrum amplitude using the complete data set. We search for spatial correlations in the observations by hierarchically analyzing individual pulsar pairs, which also allows for significance validation through randomizing pulsar positions on the sky. For a process with
α
= −2/3, we measure spatial correlations consistent with a GWB, with an estimated false-alarm probability of
p
≲ 0.02 (approx. 2
σ
). The long timing baselines of the PPTA and the access to southern pulsars will continue to play an important role in the International Pulsar Timing Array.
The global network of terrestrial protected areas (PAs) has experienced a fourfold expansion since the 1970s. Yet, there is increasing debate around the role of the global PA estate in covering and ...sustaining threatened species, with serious ramifications for current PA financing and the setting of post‐2020 global conservation targets. By comparing “past” (1970s) and current distribution range of 237 mammals, and measuring the proportion of range covered by PAs in the past and in the present, we show that a small number of PAs have now become the last bastions of hope for ensuring the persistence of many mammal species. For 187 species (∼79% of those analyzed) the proportion of range covered by PAs has doubled over the time period, with 10% of all species now having most of their current range protected. This increase in proportional protection over time is largely due to a retreat of species distribution (outside existing PAs) and, in smaller part, to PA expansion. It is clear that adequately resourcing those PAs critical in sustaining mammal species is now essential, to avert a worldwide rapid mammal loss.
Protected areas (PAs) are a key tool in efforts to safeguard biodiversity against increasing anthropogenic threats. As signatories to the 2011–2020 Strategic Plan for Biodiversity, 196 nations ...pledged support for expansion in the extent of the global PA estate and the quality of PA management. While this has resulted in substantial increases in PA designations, many sites lack the resources needed to guarantee effective biodiversity conservation. Using management reports from 2167 PAs (with an area representing 23% of the global terrestrial PA estate), we demonstrate that less than a quarter of these PAs report having adequate resources in terms of staffing and budget. Using data on the geographic ranges of the 11,919 terrestrial vertebrate species overlapping our sample of PAs, we estimate that only 4–9% of terrestrial amphibians, birds, and mammals are sufficiently represented within the existing global PA estate, when only adequately resourced PAs are considered. While continued expansion of the world’s PAs is necessary, a shift in emphasis from quantity to quality is critical to effectively respond to the current biodiversity crisis.
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