Topic 3: Biodiversity and conservation

• Total diversity of living systems • Habitat diversity, species diversity, genetic diversity

• Components of diversity contribute to ecological system resilience

• Cumulative change in heritable characteristics

• Mechanism driving evolutionary change • Operates continuously over billions of years

• Variation, overproduction, competition for limited resources • Differences in adaptation affect survival and reproduction rates • Heritable variation → increased frequency of advantageous genes

• Generation of new species through evolution • Population isolation → adaptation → inability to interbreed

• Richness: number of species in community • Evenness: similarity of population sizes

• Quantitative measure of species diversity • Allows ecosystem comparison and monitoring change over time

• Knowledge of global and regional biodiversity is needed for the development of effective management strategies to conserve biodiversity • Include: how knowledge of biodiversity is gathered in the local region • This is likely to involve citizen science and the work of voluntary and government-funded agencies • The training of indigenous people and others, such as parabiologists, is also used to gather information for use in conservation management

• Mutation and sexual reproduction increase genetic diversity • Mutation generates new variants of genes; sexual reproduction generates new combinations of genes

• Reproductive isolation can be achieved by geographical separation or, for populations living in the same area, by ecological or behavioural differences • Include: two contemporary examples of speciation and their causes • (Examples such as giraffes are unsuitable as they illustrate evolutionary change rather than speciation.) Separation of bonobos • Consider: reasons for high rates of endemism on isolated islands

• Biodiversity is spread unevenly across the planet, and certain areas contain a particularly large proportion of species, especially species that are rare and endangered • Many biodiversity hotspots are in tropical biomes

• Human activities have impacted the selective forces acting on species within ecosystems, resulting in evolutionary change in these species • Consider: human activities that have affected natural selection, e.g., climate change due to burning fossil fuels, hunting/poaching/harvesting, or creation of new habitats • Include: the example of the tuskless elephants in Gorongosa, Mozambique or a local example

• Artificial selection reduces genetic diversity and, consequently, species resilience • Include: the distinction between natural selection, which is not deliberate, and artificial selection • The vulnerability of artificially selected species (livestock or crops) can be used to highlight the importance of genetic diversity to preserve resilience within a population • Consider: the value of genetic diversity from both economic and environmental perspectives

• Earth history extends over a period of 4.5 billion years • Processes that occur over an extended timescale have led to the evolution of life on Earth • Include: the role of fossils in explaining the evolution of life over the geological timescale

• Earth history is divided up into geological epochs according to the fossil record • The geological timescale is divided into eons, which are further classified into eras, periods and epochs • Changes in these time frames are marked by major geological and biological events • The division between one epoch and the next is marked by significant changes in fossils, indicating environmental changes causing many extinctions

• Mass extinctions are followed by rapid rates of speciation due to increased niche availability • The five mass extinctions in the past have been caused by various factors, such as tectonic plate movements, super-volcanic eruption, climatic changes, sea-level changes

• The Anthropocene is a proposed geological epoch characterized by rapid environmental change and species extinction due to human activity • There is debate about the existence and beginning of the Anthropocene epoch • Various start dates have been proposed for the epoch • Suitable “golden spikes” in the geological strata marking the proposed beginning include the 1610 dip in carbon dioxide caused by the arrival of Europeans in the Americas

• Human impacts are having a planetary effect, which will be detectable in the geological record • Changes to the geological record support the argument for the Anthropocene being denoted a separate epoch from the Holocene • Consider: at least four examples of evidence for the Anthropocene • Signals from chemical pollution that are currently accumulating in geological strata, with the potential to be preserved into the far future

• Direct: overharvesting, poaching, illegal pet trade • Indirect: habitat loss, climate change, pollution, invasive alien species

• Most ecosystems subject to multiple impacts • Effects amplified when combined

• Reduce biodiversity through competition, predation, diseases/parasites

• Global conservation status assessment • Based on: population numbers, rate changes, breeding potential, geographic range, threats • Status ranks: least concern (LC) to extinct (EX)

• Publicizes species vulnerability • Allows selection of conservation priorities and management strategies

• Extinct species due to human activity • Critically endangered species • Species improved by intervention

• Overexploitation of shared natural resources • Tension between individual self-interest and sustainable development • Examples: fish stocks, ocean plastic pollution

• Under threat from habitat destruction • Significant loss risk, especially in tropical biomes

• Sites contributing to global biodiversity persistence • Hold species at extinction risk or ecosystems at collapse risk

• Exploitation vs. sustainable development vs. conservation • Example: palm oil plantations in Malaysia/Indonesia

• Can be more sustainable • Challenges: population growth, economic development, climate change, lack of support

• Must be considered when addressing biodiversity loss • Impacts on indigenous and marginalized communities

• Species extinctions have crossed critical threshold • Could lead to Earth system tipping point

3.3.1Preservation justifications

• Aesthetic, ecological, economic, ethical, social

3.3.2Conservation strategies

• Species-based: ex situ (zoos, botanic gardens, CITES, seed banks) • Habitat-based: in situ (national parks, reserves, sanctuaries)

3.3.3Mixed conservation approach

• Both habitat and particular species considered • Flagship/keystone species used to justify habitat conservation

3.3.4Convention on Biological Diversity (CBD)

• UN treaty addressing species and habitat conservation • National strategies for conservation and sustainable use • Includes Nagoya Protocol (equitable sharing of genetic resources)

3.3.5Habitat conservation strategies

• Protect species by conserving natural environment • May require wild area protection or active management

3.3.6Effective conservation factors

• Understanding target species biology • Size and shape of conservation areas • Edge effects, wildlife corridors for connectivity • UNESCO biosphere reserves: pristine core, buffer zones, transition zones

3.3.7Rewilding

• Regenerates natural processes in ecosystems • Methods: apex predator reintroduction, habitat connectivity, cessation of agriculture

3.3.8Conservation measures

• Reverse biodiversity decline • Operating within biodiversity planetary boundary • Individual, collective, national, international levels

3.3.9Perspectives and conservation strategy choice

• Environmental perspectives and value systems impact choices • Success depends on: community support, funding, education, legislation, research

3.3.10(HL)—Organization success factors

• Media use, speed of response, diplomatic constraints • Financial resources, political influence

3.3.11(HL)—Positive feedback in rewilding

• Enhance biodiversity and promote ecosystem equilibrium • Triggered by rewilding and habitat restoration

3.3.12(HL)—Rewilding benefits and limitations

• Benefits vs. land-use issues (food production) • Examples: Knepp Estate, Affric Highlands, Gorongosa

3.3.13(HL)—Assessing conservation success

• Three levels: project success, community reception, best approach • Examples: Willie Smits, Wangari Maathai's Green Belt Movement

3.3.14(HL)—Ecotourism

• Generates income for protection • Can have negative societal and ecological impacts