Monarch Butterfly added to IUCN Endangered List

On July 21, 2022, IUCN placed the migratory monarch butterfly on its Red List of threatened species and classified it as endangered. Monarchs migrate across North America each year and are one of the continent’s most widely recognized species. 

The IUCN listing applies to the migratory subspecies of the monarch butterfly, or Danaus plexippus plexippus. There are two migratory populations: one east and one west of the Rocky Mountains. The eastern population migrates thousands of miles from overwintering sites in central Mexico to breeding grounds in the Upper Midwest and southern Canada. The western population migrates from overwintering sites along the Pacific Coast in California and Baja California in Mexico to breeding grounds west of the Rocky Mountains. Monarchs in other locations throughout the world, such as in Europe and many Pacific Islands, don’t migrate and are not part of the listing.

 

Main factors threatening the monarchs

There are many factors contributing to monarchs’ decline. One of the most serious threats is habitat fragmentation and loss. Habitat fragmentation occurs when urban development or agricultural expansion break up large areas of habitat into smaller, often isolated patches. This leaves fewer areas for monarchs to find the nectar-rich plants that adult butterflies feed on, or milkweed, the sole food source for monarch caterpillars.

 

Other threats include pesticides, disease, climate change and invasive species. Providing more suitable habitat for monarchs in more places could help them tolerate these stresses. 

 

Monarchs are particularly susceptible to threats during the parts of their annual cycle when many millions of them cluster together. For example, a winter storm in March 2016 killed 31%-40% of the monarchs in some overwintering colonies in central Mexico. Winter storms also blow down trees, which can reduce habitat for overwintering colonies in subsequent years. 

 

Temperature and precipitation can influence monarchs’ spring and fall migrations and breeding season success. For example, spring weather is an important factor influencing the size of the summer monarch population. Slightly warmer and drier springs produce more monarchs on the summer breeding grounds

 

IUCN estimates that the eastern monarch population has declined by 22%-72% over the past decade, and the western population has declined by 66%-91%. Evaluating trends for insect populations can be challenging because they tend to fluctuate from year to year. 

 

Monarch butterflies are not protected in the US, although the US Fish and Wildlife Service recognizes that they are at risk. The agency received a petition in 2014 to list the monarch butterfly as threatened under the Endangered Species Act. It concluded in 2020 that listing the monarch was warranted but precluded. This means that while monarchs are at risk of extinction, they are less at risk than other species that are currently higher priorities, such as the rusty patched bumblebee. That decision put monarchs on the candidate list, where the agency reviews their status every year. Only a subset of species on the IUCN Red List is also protected under the Endangered Species Act. For insects, that number is less than 20%.

 

Migratory monarchs have a huge range that extends from southern Canada to central Mexico and includes all of the contiguous US. They use many types of open habitats, from prairies to urban parks. This makes it challenging to implement and enforce regulatory actions. 

 

IUCN report points out that the decline of the eastern migratory population seems to have slowed, or even stabilized, over the past 10 years. The 2014 petition to list monarchs under the U.S. Endangered Species Act spurred many actions to support monarchs that likely contributed to slowing their decline, from planting milkweeds and nectar plants in home gardens to large-scale restoration projects

 

Supporting these efforts could provide more benefits than a listing under the Endangered Species Act. When a species is listed, the federal government produces a recovery plan that often includes restrictions on actions that threaten the species, such as hunting or land development. Studies have found that private land owners often become less willing to participate in conservation activities, such as allowing researchers to monitor the species on their property, after a species is listed. 

 

It’s hard to say whether listing monarchs would have this effect. People love monarch butterflies, and community science projects that involve activities like monitoring eggs and caterpillars and tagging monarchs are very popular. Data collected by citizen scientists has expanded what researchers know about monarchs. Many of these efforts have taken place over large areas and longtime spans that would be hard for scientists to replicate.

 

(Based on a report on the website Conversation.com)

UN Releases World Population Prospects 2022

On 11 July 2022, the Population Division of the UN Department of Economic and Social Affairs (UN DESA) released the World Population Prospects 2022, which presents the latest round of global population estimates and projections by the UN. 

Important references to India in the Report:

·      More than half of the projected increase in global population up to 2050 will be concentrated in just eight countries: the Democratic Republic of the Congo, Egypt, Ethiopia, India, Nigeria, Pakistan, the Philippines and the United Republic of Tanzania. Disparate growth rates among the world’s largest countries will re-order their ranking by size. 

·      India is projected to surpass China as the world’s most populous country during 2023. 

 

Ten key messages of the Report:

 

1. The world’s population continues to grow, but the pace of growth is slowing down. In 2020, the growth rate of the global population fell under 1 per cent per year for the first time since 1950. The latest projections by the United Nations suggest that the world’s population could grow to around 8.5 billion in 2030 and 9.7 billion in 2050; it is projected to reach a peak of around 10.4 billion people during the 2080s and to remain at that level until 2100. The world’s population is projected to reach 8 billion on 15 November 2022, and India is projected to surpass China as the world’s most populous country in 2023. 

 

2. Policies aimed at reducing fertility would have little immediate impact on the pace of global growth. Two-thirds of the projected increase in global population through 2050 will be driven by the momentum of past growth that is embedded in the youthful age structure of the current population. For this reason, further actions by Governments aimed at reducing fertility would not have a major impact on the pace of growth between now and mid-century, beyond the gradual slowdown anticipated by the projections. Nevertheless, the cumulative effect of lower fertility, if maintained over several decades, could be a more substantial reduction of global population growth in the second half of the century. 

 

3. Rapid population growth is both a cause and a consequence of slow progress in development. Sustained high fertility and rapid population growth present challenges to the achievement of sustainable development. The necessity of educating growing numbers of children and young people, for example, draws resources away from efforts to improve the quality of education. At the same time, achieving the Sustainable Development Goals (SDGs), particularly those related to health, education and gender, is likely to hasten the transition towards lower fertility in countries with continuing high levels. 

 

4. While life expectancy continues to increase globally, large disparities remain. Population growth is in part caused by declining levels of mortality, as reflected in increased levels of life expectancy at birth. Global life expectancy at birth reached 72.8 years in 2019, an improvement of almost 9 years since 1990. Further reductions in mortality are projected to result in an average global longevity of around 77.2 years in 2050. Yet in 2021, life expectancy for the least developed countries lagged 7 years behind the global average. Similarly, a male disadvantage in life expectancy is observed in all regions and countries, ranging from 7 years in Latin America and the Caribbean to 2.9 years in Australia and New Zealand.

 

5. A rising share of population in the working ages can help boost economic growth per capita. 

In most countries of sub-Saharan Africa, as well as in parts of Asia and Latin America and the Caribbean, the share of population at working ages (between 25 and 64 years) has been increasing thanks to recent reductions in fertility. This shift in the age distribution provides a time-bound opportunity for accelerated economic growth per capita, known as the “demographic dividend”. To maximize the potential benefits of a favourable age distribution, countries should invest in the further development of their human capital by ensuring access to health care and quality education at all ages and by promoting opportunities for productive employment and decent work. 

 

6. The population of older persons is increasing both in numbers and as a share of the total. 

The population above age 65 years is growing more rapidly than the population below that age. As a result, the share of global population at ages 65 and above is projected to rise from 10 per cent in 2022 to 16 per cent in 2050. At that point, it is expected that the number of persons aged 65 years or over worldwide will be more than twice the number of children under age 5 and about the same as the number under age 12. Countries with ageing populations should take steps to adapt public programmes to the growing numbers of older persons, including by establishing universal health care and long-term care systems and by improving the sustainability of social security and pension systems. 

 

7. More and more countries have begun to experience population decline. 

Fertility has fallen markedly in recent decades for many countries. Today, two-thirds of the global population lives in a country or area where lifetime fertility is below 2.1 births per woman, roughly the level required for zero growth in the long run for a population with low mortality. The populations of 61 countries or areas are projected to decrease by 1 per cent or more between 2022 and 2050, owing to sustained low levels of fertility and, in some cases, elevated rates of emigration. 

 

8. International migration is having important impacts on population trends for some countries. 

For high-income countries between 2000 and 2020, the contribution of international migration to population growth (net inflow of 80.5 million) exceeded the balance of births over deaths (66.2 million). Over the next few decades, migration will be the sole driver of population growth in high-income countries. By contrast, for the foreseeable future, population increase in low-income and lower-middle-income countries will continue to be driven by an excess of births over deaths. All countries, whether experiencing net inflows or outflows of migrants, should take steps to facilitate orderly, safe, regular and responsible migration, in accordance with SDG target 10.7. 

 

9. The COVID-19 pandemic has affected all three components of population change. 

Global life expectancy at birth fell to 71.0 years in 2021, down from 72.8 in 2019, due mostly to the impact of the coronavirus disease (COVID-19) pandemic. Available evidence about the effect of the COVID-19 pandemic on fertility levels remains mixed. In low- and middle-income countries, the availability of and the demand for contraception, as well as reported numbers of unintended pregnancies and births, have remained relatively stable. In high-income countries, where more detailed information is available from birth registration systems, it appears that successive waves of the pandemic may have generated short-term fluctuations in numbers of pregnancies and births. The pandemic severely restricted all forms of human mobility, including international migration. 

 

10. Population data provide critical information for use in development planning. 

The COVID-19 pandemic has affected many data collection operations worldwide. Countries and development partners should give priority to the ongoing 2020 round of national population censuses, as such data provide critical information to inform development planning and to assess progress towards the achievement of the SDGs.