Biodiversity is the variability of life on Earth. It can be measured on various levels. There is for example genetic variability, species diversity, ecosystem diversity and phylogenetic diversity. Diversity is not distributed evenly on Earth. It is greater in the tropics as a result of the warm climate and high primary productivity in the region near the equator. Tropical forest ecosystems cover less than one-fifth of Earth's terrestrial area and contain about 50% of the world's species. There are latitudinal gradients in species diversity for both marine and terrestrial taxa.
The carrying capacity of an environment is the maximum population size of a biological species that can be sustained by that specific environment, given the food, habitat, water, and other resources available. The carrying capacity is defined as the environment's maximal load, which in population ecology corresponds to the population equilibrium, when the number of deaths in a population equals the number of births. Carrying capacity of the environment implies that the resources extraction is not above the rate of regeneration of the resources and the wastes generated are within the assimilating capacity of the environment. The effect of carrying capacity on population dynamics is modelled with a logistic function. Carrying capacity is applied to the maximum population an environment can support in ecology, agriculture and fisheries. The term carrying capacity has been applied to a few different processes in the past before finally being applied to population limits in the 1950s. The notion of carrying capacity for humans is covered by the notion of sustainable population.
Overconsumption describes a situation where a consumer overuses their available goods and services to where they can't, or don't want to, replenish or reuse them. In microeconomics, this may be described as the point where the marginal cost of a consumer is greater than their marginal utility. The term overconsumption is quite controversial in use and does not necessarily have a single unifying definition. When used to refer to natural resources to the point where the environment is negatively affected, it is synonymous with the term overexploitation. However, when used in the broader economic sense, overconsumption can refer to all types of goods and services, including manmade ones, e.g. "the overconsumption of alcohol can lead to alcohol poisoning". Overconsumption is driven by several factors of the current global economy, including forces like consumerism, planned obsolescence, economic materialism, and other unsustainable business models and can be contrasted with sustainable consumption.
Conservation biology is the study of the conservation of nature and of Earth's biodiversity with the aim of protecting species, their habitats, and ecosystems from excessive rates of extinction and the erosion of biotic interactions. It is an interdisciplinary subject drawing on natural and social sciences, and the practice of natural resource management.
Habitat conservation is a management practice that seeks to conserve, protect and restore habitats and prevent species extinction, fragmentation or reduction in range. It is a priority of many groups that cannot be easily characterized in terms of any one ideology.
An ecological or environmental crisis occurs when changes to the environment of a species or population destabilizes its continued survival. Some of the important causes include:
Ecological restoration, or ecosystem restoration, is the process of assisting the recovery of an ecosystem that has been degraded, damaged, destroyed or transformed. It is distinct from conservation in that it attempts to retroactively repair already damaged ecosystems rather than take preventative measures. Ecological restoration can reverse biodiversity loss, combat climate change, support the provision of ecosystem services and support local economies. The United Nations has named 2021-2030 the Decade on Ecosystem Restoration.
The "World Scientists' Warning to Humanity" was a document written in 1992 by Henry W. Kendall and signed by about 1,700 leading scientists. Twenty-five years later, in November 2017, 15,364 scientists signed "World Scientists' Warning to Humanity: A Second Notice" written by William J. Ripple and seven co-authors calling for, among other things, human population planning, and drastically diminishing per capita consumption of fossil fuels, meat, and other resources. The second notice has more scientist cosigners and formal supporters than any other journal article ever published.
William Rees, FRSC, is Professor Emeritus at the University of British Columbia and former director of the School of Community and Regional Planning (SCARP) at UBC.
Human overpopulation is the idea that human populations may become too large to be sustained by their environment or resources in the long term. The topic is usually discussed in the context of world population, though it may concern individual nations, regions, and cities.
Dame Georgina Mary Mace, was a British ecologist and conservation scientist. She was Professor of Biodiversity and Ecosystems at University College London, and previously Professor of Conservation Science and Director of the Natural Environment Research Council (NERC) Centre for Population Biology, Imperial College London (2006–2012) and Director of Science at the Zoological Society of London (2000–2006).
In environmental science, a population "overshoots" its local carrying capacity — the capacity of the biome to feed and sustain that population — when that population has not only begun to outstrip its food supply in excess of regeneration, but actually shot past that point, setting up a potentially catastrophic crash of that feeder population once its food populations have been consumed completely. Overshoot can apply to human overpopulation as well as other animal populations: any life-form that consumes others to sustain itself.
Environmental issues are disruptions in the usual function of ecosystems. Further, these issues can be caused by humans or they can be natural. These issues are considered serious when the ecosystem cannot recover in the present situation, and catastrophic if the ecosystem is projected to certainly collapse.
William J. Ripple is a professor of ecology at Oregon State University in the Department of Forest Ecosystems and Society. He is best known for his research on terrestrial trophic cascades, particularly the role of the gray wolf in North America as an apex predator and a keystone species that shapes food webs and landscape structures via “top-down” pressures.
Reed F. Noss, a conservation biologist since the beginning of the field in the early 1980s, is a writer, photographer, and speaker. He retired in 2017 as Provost's Distinguished Research Professor, Pegasus Professor, and Davis-Shine Professor at the University of Central Florida. He is President and Chief Scientist for the Florida Institute for Conservation Science, Chief Science Advisor for the Southeastern Grasslands Initiative, and Chief Science Advisor for the Endangered Ecosystems Alliance. Noss' published work consists of over 350 published or in press scientific articles, book chapters, and major reports and eight published books, with another book in preparation.
Biodiversity loss happens when plant or animal species disappear completely from Earth (extinction) or when there is a decrease or disappearance of species in a specific area. Biodiversity loss means that there is a reduction in biological diversity in a given area. The decrease can be temporary or permanent. It is temporary if the damage that led to the loss is reversible in time, for example through ecological restoration. If this is not possible, then the decrease is permanent. The cause of most of the biodiversity loss is, generally speaking, human activities that push the planetary boundaries too far. These activities include habitat destruction and land use intensification. Further problem areas are air and water pollution, over-exploitation, invasive species and climate change.
Erika S. Zavaleta is an American professor of ecology and evolutionary biology at the University of California, Santa Cruz. Zavaleta is recognized for her research focusing on topics including plant community ecology, conservation practices for terrestrial ecosystems, and impacts of community dynamics on ecosystem functions.
Conservation paleobiology is a field of paleontology that applies the knowledge of the geological and paleoecological record to the conservation and restoration of biodiversity and ecosystem services. Despite the influence of paleontology on ecological sciences can be traced back at least at the 18th century, the current field has been established by the work of K.W. Flessa and G.P. Dietl in the first decade of the 21st century. The discipline utilizes paleontological and geological data to understand how biotas respond to climate and other natural and anthropogenic environmental change. These information are then used to address the challenges faced by modern conservation biology, like understanding the extinction risk of endangered species, providing baselines for restoration and modelling future scenarios for species range's contraction or expansion.
Ecological overshoot is the phenomenon which occurs when the demands made on a natural ecosystem exceed its regenerative capacity. Global ecological overshoot occurs when the demands made by humanity exceed what the biosphere of Earth can provide through its capacity for renewal.
30 by 30 is a worldwide initiative for governments to designate 30% of Earth's land and ocean area as protected areas by 2030. The target was proposed by a 2019 article in Science Advances, "A Global Deal for Nature: Guiding principles, milestones, and targets", highlighting the need for expanded nature conservation efforts to mitigate climate change. Launched by the High Ambition Coalition for Nature and People in 2020, more than 50 nations had agreed to the initiative by January 2021, which has increased to more than 100 countries by October 2022.
