Articles tagged with Natural Populations
The current Brazil nut harvesting practices are not sustainable in the long term due to disrupted regeneration cycles, leading to a dwindling number of older trees. The researchers recommend close monitoring and management of exploited populations to avoid future failures and encourage younger tree establishment.
Scientists tested the founder effect model in a natural population of Silvereye birds, finding that speciation occurs gradually, not suddenly. The study challenges long-held assumptions about genetic diversity in island bird populations.
Researchers used paleoenvironmental techniques to study West Coast salmon populations over 2000 years, finding low population numbers in ancient periods solely due to natural fluctuations. Climatic change is the primary cause for past fluctuations, while humans have contributed to decline, particularly in southern range.
A unique study on lizard populations reveals that the presence of a top predator can make prey populations more vulnerable to catastrophic events. The researchers found that on islands without predators, mice populations rebounded quickly after a natural disaster, whereas those with predators struggled to recover and some became extinct.
Researchers discover a ring species of greenish warblers with gradually changing behavioral and genetic characteristics encircling the Tibetan Plateau. The study reveals how small evolutionary changes can lead to reproductive isolation between species.
A study by Dr. Dallas Swallow and colleagues found that the lactase gene was shaped by two evolutionary periods: one before and one after fresh milk became available. The researchers discovered that genetic diversity in non-African populations is lower than in Africans, suggesting a loss of genetic variation due to random fluctuations ...
Researchers at U.S. Geological Survey and University of Denver have identified a new bird species, the Gunnison sage-grouse, through DNA analysis and genetic research. The study confirms the species' distinctiveness from the Greater sage-grouse and highlights concerns about its low genetic diversity and population decline.
In a study on arctic ground squirrels, researchers found that females severely reduced reproduction and most died over winter when populations reached maximum capacity. This regulation helps control population growth and maintain survival rates.
A team of scientists has established a formula to predict population dynamics for species more complex than single-celled organisms. Their research uses long-duration experiments and demonstrates that simple mathematical models can govern predator-prey interactions.
The article highlights the growing crisis of reptile extinction, citing habitat loss, invasive species, and human activities as major threats. Dr. Whit Gibbons' research suggests that reptiles are in greater danger of extinction than amphibians due to similar but more severe impacts from environmental factors.
A recent study by Dr. Whit Gibbons has discovered the smallest and youngest non-hatchling Blanding's turtle ever recorded, just two and a half inches long and four years old. The finding highlights the importance of understanding the species' life cycle and habitat needs to inform conservation efforts.
USGS scientists have linked recent boreal toad deaths in Rocky Mountain National Park to a chytrid fungus. The fungus has been identified as the cause of amphibian die-offs globally and is being studied for its origin, incidence, distribution, and control methods.
A new Cornell University study suggests that without democratic population-control practices and resource-management policies, the world's 2 billion people will face a difficult life by 2100. The report predicts an optimal population of 2 billion, with a standard of living about half that of the United States in the 1990s.
Researchers found mitral-valve prolapse is substantially less common than initially believed, affecting about 2% of the population, not 5-35%. The condition also has lower rates of associated complications like stroke and heart failure compared to previous estimates.
The USGS conducts a continent-wide bird survey using over 2,500 skilled amateur birders and professional biologists. The organization also monitors water quality at abandoned mines, assesses woodcock survival, and launches the Frogwatch USA program to engage scientists and the public in amphibian conservation.
The 1999 Tyler Prize honors Te-Tzu Chang's research on rice genetics and conservation, which has led to major advances in plant breeding, productivity, and disease resistance. Joel E. Cohen's contributions to understanding food webs and population growth have also had a lasting impact on both.
A new study found that cannibalism among flour beetles regulates population growth and stabilization. By manipulating life stages, researchers demonstrated a link between cannibalism and stable populations.
The US has achieved an all-time high in life expectancy, with a decline in infant mortality rates and teen pregnancy. Despite progress, there are still areas that require further improvement, such as preventable fatal injuries to children and low-birth-weight rates.
Researchers at the University of Chicago have discovered a molecular mechanism that allows organisms to evolve new traits in response to environmental stress. The mechanism involves the protein heat shock protein 90 (Hsp 90), which normally keeps genetic variations silent but can reveal them during times of stress.
Researchers from UC Davis and Washington University found that larger organisms were more resistant to hurricanes' immediate impact, but the most prolific ones recovered faster. After a year, lizard populations had not changed, while spider numbers returned to pre-hurricane levels.
A 1996 hurricane study found that recovery rates increase with dispersal ability and size, while larger organisms are more resistant to moderate disturbance. The researchers also discovered that tidal surges can cause devastation on low-lying islands.
Anthropologist David Price warns that world population's dire Malthusian 'correction' is inevitable due to finite resources. Despite progress in measures to prevent overpopulation, the stakes are higher now than ever, with proportionately more loss expected.
A three-year study in Illinois found that planned burning in oak savannas enhances certain bird species, such as the red-headed woodpecker and northern oriole. The findings suggest that fire can select against some species but benefit others, leading to a more diverse bird community.
The report examines residents' fears about wolf interactions with livestock, humans, and the native deer population. Despite these concerns, states with wolves have minimal livestock losses, highlighting a more nuanced understanding of wolf ecology.
A University of Georgia ecologist has estimated the relative importance of predation and plant quality on insect populations using time-series analysis. The study found that top-down forces regulate winter moth populations, while bottom-up forces dominate green oak leaf roller moth populations.
Researchers found that Conservation Reserve Program lands provide substantial breeding habitat for small grassland birds. The study suggests the program may be helping to stem decline in bird populations, with some species experiencing long-term population increases.
A new government report reveals progress and signs of persistent underrepresentation of women and minorities in science and engineering occupations. Women's grades among first-year college students planning STEM majors are higher than men's, but they still earn fewer degrees and face a substantial pay gap.
A multiyear project may provide ecological insights for animal conservation, as tiny prairie voles adjusted to both immigration and emigration among different habitats to maintain a stable overall population. The study found that birth and death rates compensated for movement among habitats with varying environments.
A genetic analysis by University of Illinois researchers reveals that Illinois Prairie Chickens have lost significant genetic diversity due to population decline, affecting their fitness. The study suggests introducing birds from neighboring states may help restore the species' numbers and health.