27 research outputs found
Where the wild things were: intrinsic and extrinsic extinction predictors in the worldâs most depleted mammal fauna
Preventing extinctions requires understanding macroecological patterns of
vulnerability or persistence. However, correlates of risk can be nonlinear,
within-species risk varies geographically, and current-day threats cannot
reveal drivers of past losses. We investigated factors that regulated survival
or extinction in Caribbean mammals, which have experienced the globally
highest level of human-caused postglacial mammalian extinctions, and
included all extinct and extant Holocene island populations of non-volant
species (219 survivals or extinctions across 118 islands). Extinction selectivity
shows a statistically detectable and complex body mass effect, with survival
probability decreasing for both mass extremes, indicating that intermediatesized species have been more resilient. A strong interaction between mass
and age of first human arrival provides quantitative evidence of larger mammals going extinct on the earliest islands colonized, revealing an extinction
filter caused by past human activities. Survival probability increases on
islands with lower mean elevation (mostly small cays acting as offshore
refugia) and decreases with more frequent hurricanes, highlighting the
risk of extreme weather events and rising sea levels to surviving species
on low-lying cays. These findings demonstrate the interplay between intrinsic biology, regional ecology and specific local threats, providing insights
for understanding drivers of biodiversity loss across island systems and
fragmented habitats worldwide
Anthropogenic extinction dominates Holocene declines of West Indian mammals
The extensive postglacial mammal losses in the West Indies provide an opportunity to evaluate extinction dynamics, but limited data have hindered our ability to test hypotheses. Here, we analyze the tempo and dynamics of extinction using a novel data set of faunal last-appearance dates and human first-appearance dates, demonstrating widespread overlap between humans and now-extinct native mammals. Humans arrived in four waves (Lithic, Archaic, Ceramic, and European), each associated with increased environmental impact. Large-bodied mammals and several bats were extinct by the Archaic, following protracted extinction dynamics perhaps reflecting habitat loss. Most small-bodied rodents and lipotyphlan insectivores survived the Ceramic, but extensive landscape transformation and the introduction of invasive mammals following European colonization caused further extinctions, leaving a threatened remnant fauna. Both large- and small-bodied nonvolant mammals disappeared, reflecting complex relationships between body size, ecology, and anthropogenic change. Extinct bats were generally larger species, paralleling declines from natural catastrophes
Genomic insights into the host specific adaptation of the Pneumocystis genus
Pneumocystis jirovecii, the fungal agent of human Pneumocystis pneumonia, is closely related to macaque Pneumocystis. Little is known about other Pneumocystis species in distantly related mammals, none of which are capable of establishing infection in humans. The molecular basis of host specificity in Pneumocystis remains unknown as experiments are limited due to an inability to culture any species in vitro. To explore Pneumocystis evolutionary adaptations, we have sequenced the genomes of species infecting macaques, rabbits, dogs and rats and compared them to available genomes of species infecting humans, mice and rats. Complete whole genome sequence data enables analysis and robust phylogeny, identification of important genetic features of the host adaptation, and estimation of speciation timing relative to the rise of their mammalian hosts. Our data reveals insights into the evolution of P. jirovecii, the sole member of the genus able to infect humans.http://deepblue.lib.umich.edu/bitstream/2027.42/174884/2/Genomic insights into the host specific adaptation of the Pneumocystis genus.pdfPublished versio