Feb | 2023 | ConservationBytes.com

Better codes of practice for control of feral animals

24 02 2023

From time to time I turn my research hand to issues of invasive species control, for example, from manipulating pathogens to control rabbits, to island eradication of feral cats and pigs, to effective means to control feral deer.

Not only do invasive species cost well over $1.7 trillion (yes, that’s trillion, with 12 zeros) each year in terms of damage and control (a minimum of $25 billion per year in Australia alone), they are one of the main drivers of biodiversity loss globally. So, if you baulk at lethal forms of control of invasive species, you are simultaneously stating that you’re fine with the torture and death of millions (if not, billions) of native animals each year.

Thanks to the collaborative and evidence-driven foresight of my colleagues at PIRSA Biosecurity and Landscape Boards, I was recently involved in more research examining the most efficient, cost-effective, and humane ways to cull feral dear in South Australia. The resulting paper is now in review in NeoBiota, but we have also posted a pre-print of the article.

Feral deer are a real problem in Australia, and South Australia is no exception. With six species of feral deer in the country already (fallow Dama dama, red Cervus elaphus, hog Axis porcinus, chital A. axis), rusa C. timorensis, and sambar Rusa unicolor deer), fallow deer are the most abundant and widespread. These species are responsible for severe damage to native plants, competition with native animals, economic losses to primary industries (crops, pastures, horticulture, plantations), and human safety risks from vehicle collisions. Feral deer are also reservoirs and vectors of endemic animal diseases and have the potential to transmit exotic animal diseases such as foot-and-mouth. If left uncontrolled, within 30 years the economic impacts of feral deer could reach billions of dollars annually.

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Tags: cost of invasive species, Dama dama, deer, Fallow deer, feral deer, InvaCost, invasion biology, invasive alien species, invasive species control
Categories : alien species, animal welfare, Australia, cat, conservation, environmental science, harvest, human-wildlife conflict, invasive species, mammal, management, research, South Australia

Keeping babies alive will lower population growth

23 02 2023

We’ve just published a paper in PLOS ONE showing high infant mortality rates are contributing to an incessant rise of the global human population, which supports arguments for greater access to contraception and family planning in low- and middle-income nations.

In collaboration with Melinda Judge, Chitra Saraswati, Claire Perry, Jane Heyworth, and Peter Le Souëf of the University of Western Australia‘s School of Medicine and the Telethon Kids Institute, we found that higher baby death rates and larger household sizes (as an indicator of population density) lead to higher fertility rates.

In the first study of its kind, we provide a compelling argument that the United Nations’ Sustainable Development Goals for reducing infant mortality can be accelerated by increasing access to family planning.

Although it sounds counterintuitive, higher baby death rates are linked to higher population growth because the more babies a women loses, the more children she is likely to have. Family planning, including access to quality contraception, enables women to plan pregnancies better and therefore reduce infant mortality to curb the so-called ‘replacement’, or ‘insurance’ effect.

We evaluated six conditions thought to influence a woman’s fertility — availability of family planning, quality of family planning, education, religion, mortality, and socio-economic conditions, across 64 low- to middle-income countries.

Specifically, we tested whether

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Tags: child mortality, children, contraception, family planning, fertility, human population size, overpopulation, population density, Population size, SDGs, Sustainable Development Goals, United Nations
Categories : Africa, Asia, Central America, education, ethics, gender, health, human overpopulation, poverty, sustainability

Remapping the superhighways travelled by the first Australians reveals a 10,000-year journey through the continent

3 02 2023

Not exactly a conservation topic, I know, but it does provide insights into how the ancestors of Indigenous Australians adapted to and thrived in a new and sometimes harsh landscape. The more I study elements of human ecology in deep time, the more awed I become at the frankly amazing capacity of First Peoples.

Our new research (co-authored by Stefani Crabtree, Devin White, Sean Ulm, Michael Bird, Al Williams, and Fred Saltré) has revealed that the process of peopling the entire continent of Sahul — the combined mega continent that joined Australia with New Guinea when sea levels were much lower than today — took 10,000 years.

We combined new models of demography and wayfinding based on geographic inference to show the scale of the challenges faced by the ancestors of Indigenous people making their mass migration across the supercontinent more than 60,000 years ago.

The ancestors of Aboriginal people likely first entered the continent 75,000–50,000 years ago from what is today the island of Timor, followed by later migrations through the western regions of New Guinea.

This pattern led to a rapid expansion both southward toward the Great Australian Bight, and northward from the Kimberley region to settle all parts of New Guinea and, later, the southwest and southeast of Australia.

We did this research under the auspices of the ARC Centre of Excellence for Australian Biodiversity and Heritage (CABAH) and including international experts in Australia and the United States to investigate the most likely pathways and the timeframe needed to reach population sizes able to withstand the rigours of their new environment.

By combining two existing models predicting the routes these First Peoples took – ‘superhighways’ – and the demographic structure of these first populations, we were able to estimate the time for continental saturation more precisely. The new research has just been published in the journal Quaternary Science Reviews.

Based on detailed reconstructions of the topography of the ancient continent and models of past climate, we developed a virtual continent and programmed populations to survive in and move successfully through their new territory.

Navigating by following landscape features like mountains and hills and knowing where to find water led to successful navigation strategies. The First Peoples of Australia soon passed along cultural knowledge to subsequent generations facilitating the peopling of the whole continent.

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