Chapter 56 - Conservation Biology and Global Change

Human actions are changing natural disturbances, trophic systems, energy flow, and chemical cycling across the biosphere—ecosystem processes on which we and all other species rely.

We have physically changed approximately half of the Earth's land area and utilize more than half of all available surface freshwater.

Overfishing is reducing the stocks of most major fisheries in the oceans. According to some estimates, humanity may be driving more species to extinction than the asteroid that caused the Cretaceous mass extinction 66 million years ago.

The third degree of biological diversity is the diversity of ecosystems on Earth. Due to the numerous interconnections between various species in an ecosystem, the extinction of one species' populations might have a severe influence on other species in the ecosystem. For example, in the Pacific Islands, where they are being sought as a luxury meal, bats known as "flying foxes" are key pollinators and seed dispersers.

Conservation scientists are concerned that the loss of flying foxes may affect the native flora of the Samoan Islands, where four-fifths of the tree species rely on them for pollination or seed dissemination.

Humans have already had a significant impact on certain ecosystems, while others are changing at a rapid pace. More than half of the wetlands in the contiguous United States have been drained and converted to agriculture and other purposes since European settlement.

Overgrazing, flood control, water diversions, lowering of water tables, and invasion by non-native plants have all had an impact on nearly 90% of native riparian (streamside) ecosystems in California, Arizona, and New Mexico.

Our biophilia helps us to appreciate the significance of biodiversity in and of itself. Other species also offer food, fiber, medications, and ecological services to humans.

Habitat loss, invasive species, overharvesting, and global change are the four primary threats to biodiversity.

Population conservation is concerned with issues like population size, genetic variety, and essential habitat.

When a population falls below the size of a minimum viable population (MVP), the loss of genetic variation caused by nonrandom mating and genetic drift can trap it in an extinction vortex.

The declining-population approach, regardless of absolute population size, focuses on the environmental variables that drive decline.

It adheres to a step-by-step conservation plan.

Species conservation frequently necessitates addressing conflicts between endangered species' habitat needs and human expectations.

Landscape and regional conservation aid in the preservation of biodiversity.

The structure of a landscape can have a significant impact on biodiversity.

Biodiversity tends to decline when habitat fragmentation grows and edges become more widespread. Movement lanes can help disperse people and maintain them.

Biodiversity hotspots are also extinction hotspots, making them excellent candidates for conservation. To preserve biodiversity in parks and reserves, managers must guarantee that human activities in the surrounding landscape do not affect the protected ecosystems.

The zoned reserve approach emphasizes that conservation efforts sometimes require working in landscapes that have been substantially influenced by human activity.

As a result of human activity, the Earth is quickly changing.

Because agriculture depletes plant nutrients in ecosystems, substantial supplements are generally necessary. Fertilizer nutrients can contaminate groundwater and surface-water aquatic environments, where they can promote excessive algal growth (eutrophication).

Toxic wastes and medicines have contaminated the environment with hazardous chemicals that often remain for extended periods of time and become progressively concentrated in food webs at higher trophic levels (biological magnification).

Because of the usage of fossil fuels and other human activities, the concentration of CO2 and other greenhouse gases in the atmosphere has increased.

Sustainable development may enhance people's lives while protecting biodiversity.

The Sustainable Biosphere Initiative seeks to collect ecological data for the development, administration, and conservation of Earth's resources.

Costa Rica's achievement in protecting tropical biodiversity has been achieved via collaboration between the government, other organizations, and private residents. Costa Rica's human living circumstances have improved in tandem with environmental protection.

We become increasingly conscious of our tight connection to the environment and the worth of other species that share it as we learn about biological processes and the diversity of life.