Early evidence for historical overfishing in the Gulf of Mexico

Fisheries encompass complex interplays between social, economic, and environmental factors, but limitations on historical fisheries data can hamper efforts to identify and contextualize the long-term spatiotemporal patterns that shape them. We integrate 2500 years of stable isotope (δ34S, δ13C, and δ15N) and zooarchaeological evidence from Gulf of Mexico fisheries to assess cultural, demographic, and technological changes affecting sheepshead (Archosargus probatocephalus) populations and fishing practices in Louisiana, USA. Concurrent with human population growth, average sizes of sheepshead caught decreased from the 1720s to 1830s. The size of fish caught after the 1830s increased to pre-1720 levels at the same time that isotopic compositions of fish bone collagen show that fish were being caught from a more diverse range of ecosystems, including distant seagrass beds. Our findings provide the first evidence for large-scale depressions of historical sheepshead populations and the processes driving them, including rapid human population growth and sustained harvesting pressure.

Tree phylogenetic diversity supports nature’s contributions to people, but is at risk from human population growth

ABSTRACTThere is growing evidence for a link between biodiversity and ecosystem function, and for a correlation between human population and the species diversity of plants and animals in a region. Here, we suggest these relationships might not be independent. Using a comprehensive phylogeny of southern African trees and structural equation modelling, we show that human population density correlates with tree phylogenetic diversity and show that this relationship is stronger than the correlation with species richness alone. Further, we demonstrate that areas high in phylogenetic diversity support a greater diversity of ecosystem goods and services, indicating that the evolutionary processes responsible for generating variation among living organisms are also key to the provisioning of nature’s contributions to people. Our results raise the intriguing possibility that the history of human settlement in southern Africa may have been shaped, in part, by the evolutionary history of its tree flora. However, the correlation between human population and tree diversity generates a conflict between people and nature. Our study suggests that future human population growth may threaten the contributions to people provided by intact and phylogenetically diverse ecosystems.

Agroecosystem energy, ecological human imprint and economic sustainability: Analysis and impacts

Agroecosystem energy is an essential part of the natural resources available to humans for use and the continuation of Earth's life cycle. Without energy, life on this Earth will stop, and the drivers of all ecological life cycles will not be able to continue function. Energy is an essential factor that makes the working process of human survivability possible. According to World Population Clock, the current status of human population growth is in an alarming situation (i.e., 7.81 billion people and continues to increase) [World Population Clock 2020 Accessed September 20, 2020][ World Population Clock, 2020). Therefore, the ecological human imprint will impact all Earth's natural resources, in the forms of more consumptions and demands that will have impacts on the global social and economic issues globally. Sustainability will be accomplished if we live within the concept of Nature, controlling our human population growth to reduce the impacts on natural resources' demands. In this respect, sustainability will not be achieved by economic growth alone; instead, the biosphere natural resources must replenish it and allow the natural resources to regenerate itself to support the growing human population. The present paper will assess the agroecosystem energy continuing ongoing demands and availability concerning human population growth by modeling different scenarios. According to our model, the human population growth will reach 10 billion people or more by the year 2050 at the current trend, and we may be faced with shortening the availability of energy. It is important to stress that the energy should be replenished through non-tradition energy supply, and we have to concentrate on renewable energy, which we can develop to the extent of harvesting this energy in efficient ways. An example of the needs of energy in the agroecosystem is to calculate how much enough the Earth has to support the human beings. In this regard, if each human being is in need of 2000 calories/per day on average, this means that globally the Earth has to produce more than 5694 trillion calories per year. The question is whether the Earth can create these calories to support 7.81 billion people, and we need more calories when the human population grows to be more than 7.81 bil lion people. Therefore, engineering of the Earth agroecosystem should be significant, and we have to think about how we accomplish it. Additionally, we need to sustain our environment by conserving our water resources and keeping our global climate environmentally in the best condition to maintain international economic and social standards. Further, in this paper, we will discuss the impacts of changing different parameters that affect global agroecosystem energy.

Climate and other global factors at the zoonotic interface in America: influence on diseases caused by tick-borne pathogens.

This expert opinion discusses evidence for global change (including rapid human population growth) and climate change impacts on the distribution and abundance of ticks on human and animal hosts as well as the prevalence and intensity of tick-borne diseases at the zoonotic interface in America.

Earth Stewardship

This chapter addresses the interactions of individuals with government, business, and other institutions to build upon and support individual efforts. It emphasizes sustainable outcomes at regionally and globally significant scales. Global changes that threaten Earth’s ecosystems and society could be reversed through progress toward four key stewardship goals: reducing atmospheric concentrations of greenhouse gases, increasing the extent of forests and wetlands, sustaining ecosystem services, and reducing human population growth and unnecessary consumption. The US Declaration of Independence radically included “pursuit of happiness” as an inalienable right of all people. Since happiness is generally unrelated to consumption or wealth, society’s happiness and well-being can often be enhanced without increasing consumption. The chapter outlines five potential strategies by which government can complement the efforts of individuals to foster happiness. If people decide, individually and collectively, that the planet’s future habitability is important, they will know how to ensure a better life for their grandchildren.