31 research outputs found
Human footprint and protected areas shape elephant range across Africa
Over the last two millennia, and at an accelerating pace, the African elephant (Loxodonta spp. Lin.) has been threatened by human activities across its range. We investigate the correlates of elephant home range sizes across diverse biomes. Annual and 16-day elliptical time density home ranges were calculated by using GPS tracking data collected from 229 African savannah and forest elephants (L. africana and L. cyclotis, respectively) between 1998 and 2013 at 19 sites representing bushveld, savannah, Sahel, and forest biomes. Our analysis considered the relationship between home range area and sex, species, vegetation productivity, tree cover, surface temperature, rainfall, water, slope, aggregate human influence, and protected area use. Irrespective of these environmental conditions, long-term annual ranges were overwhelmingly affected by human influence and protected area use. Only over shorter, 16-day periods did environmental factors, particularly water availability and vegetation productivity, become important in explaining space use. Our work highlights the degree to which the human footprint and existing protected areas now constrain the distribution of the worldâs largest terrestrial mammal. A habitat suitability model, created by evaluating every square kilometer of Africa, predicts that 18,169,219 km2 would be suitable as elephant habitatâ62% of the continent. The current elephant distribution covers just 17% of this potential range of which 57.4% falls outside protected areas. To stem the continued extirpation and to secure the elephantsâ future, effective and expanded protected areas and improved capacity for coexistence across unprotected range are essential
Wide-scale subdivision and fencing of southern Kenyan rangelands jeopardizes biodiversity conservation and pastoral livelihoods : demonstration of utility of open-access landDX database
DATA AVAILABILITY STATEMENT : Publicly available datasets were analyzed in this study. This
data can be found here: https://www.nature.com/articles/
s41597-021-01100-9.Globally, rangelands are undergoing rapid social-ecological changes, yet the
scale of these changes is rarely measured. Fencing, sedentarization, and land
conversion limit access by wildlife and livestock to vital resources such as water
and seasonal forage, leading to rangeland degradation. In addition, these
changes limit connectivity between wildlife sub-populations, triggering a
spiral of decreasing biodiversity and weakening ecosystem function.
Moreover, the combination of land privatization, sedentarization and fencing
endangers pastoral livelihoods by reducing resilience to drought and
diminishing livestock holdings per person. We provide a unique, urgent, and
vital snapshot across >30,000 km2 of southern Kenyaâs rangeland, covering
four ecosystems renowned for their rich megafauna and pastoral people. We
document and explore the drivers of extensive fencing (~40,000 km), the
proliferation of livestock enclosures (>27,000), and the conversion of
rangelands for cultivation (~1,500 km2). Our analyses were based on an
open-access database recently synthesized for the region. Fencing is
generally more prolific in areas that have been converted from community
tenure to private title, especially where land values are raised by agricultural
potential and proximity to Kenyaâs capital, Nairobi. These factors drive the transfer of land ownership from traditional pastoralists to speculators,
eventually resulting in the transformation of rangeland into agricultural,
industrial and urban land uses. Space for wildlife (and traditional pastoralism)
is limited on private, subdivided land, where livestock enclosures are at their
highest density, and where there is less unfenced land and less untransformed
land, compared to conservation areas and pastoral commons. Conflicting
planning incentives, policies, and economic forces are driving unsustainable
and potentially irreversible social-ecological transitions over unprecedented
spatial scales. The lesson from southern Kenya is that a range of financial, policy
and governance-related interventions are required to allow people and nature
to coexist sustainably in African savannas.The Ralph Mistler Scholarship at WildCRU, VILLUM Investigator project âBiodiversity Dynamics in a Changing Worldâ, funded by VILLUM FONDEN and Center for Ecological Dynamics in a Novel Biosphere (ECONOVO), funded by Danish National Research Foundation as well as the Maasai Landscape Conservation Fund.https://www.frontiersin.org/journals/conservation-scienceam2023Mammal Research InstituteZoology and Entomolog
The mTORC1 inhibitor everolimus prevents and treats EΌ-Myc lymphoma by restoring oncogene-induced senescence
MYC deregulation is common in human cancer. IG-MYC translocations that are modeled in EÎŒMyc mice occur in almost all cases of Burkitt lymphoma as well as in other B-cell lymphoproliferative disorders. Deregulated expression of MYC results in increased mTOR complex 1 (mTORC1) signaling. As tumors with mTORC1 activation are sensitive to mTORC1 inhibition, we used everolimus, a potent and specific mTORC1 inhibitor, to test the requirement for mTORC1 in the initiation and maintenance of EÎŒMyc lymphoma. Everolimus selectively cleared premalignant B cells from the bone marrow and spleen, restored a normal pattern of B-cell differentiation, and strongly protected against lymphoma development. Established EÎŒMyc lymphoma also regressed after everolimus therapy. Therapeutic response correlated with a cellular senescence phenotype and induction of p53 activity. Therefore, mTORC1-dependent evasion of senescence is critical for cellular transformation and tumor maintenance by MYC in B lymphocytes
Genomic characterisation of EΌ-Myc mouse lymphomas identifies Bcor as a Myc co-operative tumour-suppressor gene
The EΌ-Myc mouse is an extensively used model of MYC driven malignancy; however to date there has only been partial characterization of MYC co-operative mutations leading to spontaneous lymphomagenesis. Here we sequence spontaneously arising EΌ-Myc lymphomas to define transgene architecture, somatic mutations, and structural alterations. We identify frequent disruptive mutations in the PRC1-like component and BCL6-corepressor gene Bcor. Moreover, we find unexpected concomitant multigenic lesions involving Cdkn2a loss and other cancer genes including Nras, Kras and Bcor. These findings challenge the assumed two-hit model of EΌ-Myc lymphoma and demonstrate a functional in vivo role for Bcor in suppressing tumorigenesis.We acknowledge the following
funding agencies: Leukaemia Foundation of Australia, Arrow Bone Marrow Transplant
Foundation, National Health and Medical Research Council Australia, Cancer Council
Victoria, Victorian Cancer Agency, Australian Cancer Research Foundation, Peter
MacCallum Cancer Centre Foundation, National Institutes of Health
Evaluating expert-based habitat suitability information of terrestrial mammals with GPS-tracking data
Aim Macroecological studies that require habitat suitability data for many species often derive this information from expert opinion. However, expert-based information is inherently subjective and thus prone to errors. The increasing availability of GPS tracking data offers opportunities to evaluate and supplement expert-based information with detailed empirical evidence. Here, we compared expert-based habitat suitability information from the International Union for Conservation of Nature (IUCN) with habitat suitability information derived from GPS-tracking data of 1,498 individuals from 49 mammal species. Location Worldwide. Time period 1998-2021. Major taxa studied Forty-nine terrestrial mammal species. Methods Using GPS data, we estimated two measures of habitat suitability for each individual animal: proportional habitat use (proportion of GPS locations within a habitat type), and selection ratio (habitat use relative to its availability). For each individual we then evaluated whether the GPS-based habitat suitability measures were in agreement with the IUCN data. To that end, we calculated the probability that the ranking of empirical habitat suitability measures was in agreement with IUCN's classification into suitable, marginal and unsuitable habitat types. Results IUCN habitat suitability data were in accordance with the GPS data (> 95% probability of agreement) for 33 out of 49 species based on proportional habitat use estimates and for 25 out of 49 species based on selection ratios. In addition, 37 and 34 species had a > 50% probability of agreement based on proportional habitat use and selection ratios, respectively. Main conclusions We show how GPS-tracking data can be used to evaluate IUCN habitat suitability data. Our findings indicate that for the majority of species included in this study, it is appropriate to use IUCN habitat suitability data in macroecological studies. Furthermore, we show that GPS-tracking data can be used to identify and prioritize species and habitat types for re-evaluation of IUCN habitat suitability data
Landscape dynamics (landDX) an open-access spatial-temporal database for the Kenya-Tanzania borderlands
The savannas of the Kenya-Tanzania borderland cover >100,000 km2 and is one of the most important
regions globally for biodiversity conservation, particularly large mammals. The region also supports
>1 million pastoralists and their livestock. In these systems, resources for both large mammals and
pastoralists are highly variable in space and time and thus require connected landscapes. However,
ongoing fragmentation of (semi-)natural vegetation by smallholder fencing and expansion of
agriculture threatens this social-ecological system. Spatial data on fences and agricultural expansion
are localized and dispersed among data owners and databases. Here, we synthesized data from several
research groups and conservation NGOs and present the first release of the Landscape Dynamics
(landDX) spatial-temporal database, covering ~30,000 km2 of southern Kenya. The data includes
31,000 livestock enclosures, nearly 40,000 kilometres of fencing, and 1,500 km2 of agricultural land.
We provide caveats and interpretation of the different methodologies used. These data are useful to
answer fundamental ecological questions, to quantify the rate of change of ecosystem function and
wildlife populations, for conservation and livestock management, and for local and governmental
spatial planning.The South Rift Association of Land Owners (specifically grants from the European Union and the Lion Recovery Fund), BigLife Foundation, Esri Conservation Program, Mara Elephant Project, Microsoft AI4Earth programme, the Carlsberg Foundation Semper Ardens project MegaPast2Future, and the VILLUM Investigator project âBiodiversity Dynamics in a Changing Worldâ funded by VILLUM FONDEN, the European Research Council (ERC) project ANTHEA.http://www.nature.com/scientificdataam2023Mammal Research InstituteZoology and Entomolog
Genome-wide Association Meta-analysis of Childhood and Adolescent Internalizing Symptoms
Objective: To investigate the genetic architecture of internalizing symptoms in childhood and adolescence. Method: In 22 cohorts, multiple univariate genome-wide association studies (GWASs) were performed using repeated assessments of internalizing symptoms, in a total of 64,561 children and adolescents between 3 and 18 years of age. Results were aggregated in meta-analyses that accounted for sample overlap, first using all available data, and then using subsets of measurements grouped by rater, age, and instrument. Results: The meta-analysis of overall internalizing symptoms (INToverall) detected no genome-wide significant hits and showed low single nucleotide polymorphism (SNP) heritability (1.66%, 95% CI = 0.84-2.48%, n(effective) = 132,260). Stratified analyses indicated rater-based heterogeneity in genetic effects, with self-reported internalizing symptoms showing the highest heritability (5.63%, 95% CI = 3.08%-8.18%). The contribution of additive genetic effects on internalizing symptoms appeared to be stable over age, with overlapping estimates of SNP heritability from early childhood to adolescence. Genetic correlations were observed with adult anxiety, depression, and the well-being spectrum (vertical bar r(g)vertical bar > 0.70), as well as with insomnia, loneliness, attention-deficit/hyperactivity disorder, autism, and childhood aggression (range vertical bar r(g)vertical bar = 0.42-0.60), whereas there were no robust associations with schizophrenia, bipolar disorder, obsessive-compulsive disorder, or anorexia nervosa. Conclusion: Genetic correlations indicate that childhood and adolescent internalizing symptoms share substantial genetic vulnerabilities with adult internalizing disorders and other childhood psychiatric traits, which could partially explain both the persistence of internalizing symptoms over time and the high comorbidity among childhood psychiatric traits. Reducing phenotypic heterogeneity in childhood samples will be key in paving the way to future GWAS success.Peer reviewe
Moving in the anthropocene: global reductions in terrestrial mammalian movements
Animal movement is fundamental for ecosystem functioning and species survival, yet the effects of the anthropogenic footprint on animal movements have not been estimated across species. Using a unique GPS-tracking database of 803 individuals across 57 species, we found that movements of mammals in areas with a comparatively high human footprint were on average one-half to one-third the extent of their movements in areas with a low human footprint. We attribute this reduction to behavioral changes of individual animals and to the exclusion of species with long-range movements from areas with higher human impact. Global loss of vagility alters a key ecological trait of animals that affects not only population persistence but also ecosystem processes such as predator-prey interactions, nutrient cycling, and disease transmission
Finishing the euchromatic sequence of the human genome
The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers âŒ99% of the euchromatic genome and is accurate to an error rate of âŒ1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead
Appendix A. A description of the real-time monitoring system for elephant tracking, with eight sections detailing each of the system components: (1) collar description and type, (2) temporal sampling regime, (3) deployment locations, (4) data telemetry, (5) data storage, (6) data analysis, (7) alert dissemination, and (8) data access.
A description of the real-time monitoring system for elephant tracking, with eight sections detailing each of the system components: (1) collar description and type, (2) temporal sampling regime, (3) deployment locations, (4) data telemetry, (5) data storage, (6) data analysis, (7) alert dissemination, and (8) data access