Between natural disasters, habitat loss, roadkill, and dog attacks, many koala populations across their eastern and south-east coastal ranges have been heavily reduced, to the point where the species is listed as endangered in parts of NSW, Queensland, and the ACT. <\/p>\n\n\n\n
According to a study published recently in Molecular Biology and Evolution <\/em>it is not the first time koala populations have declined, with results that challenge the findings from earlier studies that suggested koala populations declined only after humans arrived. Researchers from the University of Sydney and Texas A&M University found koalas experienced a severe population decline around 100,000 years ago, before humans arrived on the continent.<\/p>\n\n\n\n Led by Toby Kovacs, a PhD candidate from US\u2019s School of Life and Environmental Sciences, whose research focus is estimating the germline mutation rate in koalas and Tasmanian devils, using genome sequences of parent-offspring trios. He uses these parameters to model historical population sizes for a diverse range of marsupials over the last million years to analyse the impact of past climate change on population health. Although it is widely recognised modern koalas are all descended from a single ancestral population that survived major climate fluctuation, that included severe glacial periods, Kovacs said the study has rewritten the timeline for the koala\u2019s genetic history in Australia.<\/p>\n\n\n\n \u201cBy calculating the mutation rate of modern koala populations, we can estimate and build the genetic timeline backwards<\/em> all the way to 100,000 years ago to get a glimpse of genetic diversity and the sizes of ancient koala populations,\u201d Kovacs said, adding that fossil records are \u201ctoo sparse\u201d to know exactly how big koala populations were 100,000 ago, so studying their genomes offered vital clues to the species\u2019 evolutionary history.<\/p>\n\n\n\n \u201cGenomic analyses show that koalas have experienced major population declines in the past due to climate change and habitat loss. When environmental conditions improved, their populations recovered and expanded across much of eastern Australia. It\u2019s important to make clear many of the threats facing modern koala populations are caused by humans, and that includes habitat loss and hunting,\u201d he said.<\/p>\n\n\n\n A better understanding of how koala populations responded to past declines and recoveries can help guide the science-based conservation strategies needed to protect the species into the future.<\/p>\n\n\n\n Anne Layton-Bennett<\/strong><\/p>\n\n\n\n Picture: Luke Silver<\/p>\n\n\n\n <\/p>\n","protected":false},"excerpt":{"rendered":" Between natural disasters, habitat loss, roadkill, and dog attacks, many koala populations across their eastern and south-east coastal ranges have been heavily reduced, to the point where the species is listed as endangered in parts of NSW, Queensland, and the ACT. According to a study published recently in Molecular Biology and Evolution it is not […]<\/p>\n","protected":false},"author":1,"featured_media":3845,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[5],"tags":[],"class_list":["post-3843","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-news"],"rise-blocks_total_comments":0,"rise-blocks_categories":[{"term_id":5,"name":"News","slug":"news","term_group":0,"term_taxonomy_id":5,"taxonomy":"category","description":"","parent":0,"count":414,"filter":"raw","cat_ID":5,"category_count":414,"category_description":"","cat_name":"News","category_nicename":"news","category_parent":0}],"rise-blocks_excerpt":"Between natural disasters, habitat loss, roadkill, and dog attacks, many koala populations across their eastern and south-east coastal ranges have been heavily reduced, to the point where the species is listed as endangered in parts of NSW, Queensland, and the ACT. 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