essay

Question 1

What is Biodiversity?

Answer 1

‘Biological diversity’ means the variability among living organisms from all sources including, inter alia, terrestrial, marine and other aquatic systems and the ecological complexes of which they are part; this includes diversity within species, between species and of ecosystems by the Convention on Biological Diversity, 1992

Question 2

Overpopulation is a global ecological challenge. evidence 1

Answer 2

A study linked overpopulation to disturbance of reef fishes. They looked at 1906 reefs using standing biomass as a metric of ecosystem function and human population density as a proxy for disturbance levels. They found a negative effect of human density on reef fish functioning and that for the same number of people the loss of standing biomass is significantly larger in more diverse ecosystem.

Question 3

Overpopulation is a global ecological challenge. evidence 2

Answer 3

In the Western Ghats, a biodiversity hotspot in India, a study found that protected areas reduced forest loss overall. However, in areas with high human population density, forest loss still occurred despite protection. This suggests that population pressure can override conservation efforts

Question 4

Overpopulation is a global ecological challenge. evidence 3

Answer 4

A study modelled globally the effects of population growth on the number of threatened bird and mammal species across 114 continental nations. They found human population density was the key cause of bird and mammal species becoming threatened.

Question 5

Human induced chemical disasters are not global ecological challenges. evidence 1

Answer 5

A study looks at the effects of recurrent smaller oil spills on seabirds in South Africa. Looked at African penguins which are listed as vulnerable. After oil spill events seabirds experience reduced breeding success finding 27% of rehabilitated African penguins were unable to breed following release.

Question 6

Human induced chemical disasters are not global ecological challenges. evidence 2

Answer 6

A study looked at the impact of the BP deepwater horizon oil spill on a deep-water coral community in the Gulf of Mexico. Found major coral damage only at one site 11 km from the well, while 10 sites >20 km away showed no impact. This shows severe effects can occur locally, but impacts are limited in geographic scope.

Question 7

Human induced chemical disasters are not global ecological challenges. evidence 3

Answer 7

A study looked at the research and monitoring activities over the 28 years since the Exxon Valdez oil spill. Researchers found that chronic effects from the Exxon Valdez spill lasted decades for species like sea otters and harlequin ducks, while killer whales showed long-term decline from acute effects. Recovery varied by species, depending on life history traits. Oil spills while sever locally are not global ecological challenges.

Question 8

Radiation is not a global ecological challenge. evidence 1.

Answer 8

A study aimed to determine how far Fukushima derived radionuclides were transported via pacific bluefin tuna. They found blue fin tuna transported these radionuclides to California, However the radiocesium found in the muscle tissue of bluefine tuna was not at threatening levels and would not cause harm if consumed.

Question 9

Radiation is not a global ecological challenge. evidence 2.

Answer 9

A 22-year study in the Chernobyl Exclusion Zone showed that despite radiation, raptor communities recovered through passive rewilding. Endangered species like the Greater Spotted Eagle increased from 0 to 13 pairs, showing that reduced human activity, not radiation levels, was the stronger driver of ecological recovery.

Question 10

Radiation is not a global ecological challenge. evidence 3.

Answer 10

A study using Landsat data (1986–2020) found forest cover in the Chernobyl Exclusion Zone increased from 41% to 59% — a 1.5× gain — despite radiation. Most gains occurred after 2000 due to farmland abandonment, showing that in the absence of human activity, ecosystems can recover.

Question 11

Natural Hazards are not a global ecological challenge (humans fault). evidence 1

Answer 11

Australian wildfires 2019-2020. In a study that looked at how introduced animals compound the effects of fire on native plants and animals. In 92 ecosystems affected by the wildfires 11 were highly exposed to introduced herbivores >50% distribution. Introduced predators also became a bigger threat due to reduced shelter and food availability.

Question 12

Natural Hazards are not a global ecological challenge (humans fault). evidence 2

Answer 12

6000km2 of tree cover affected. In a study that looked at the consequences of land use change and the wildfire disaster of 2017 in Chile. Researchers determined land-use change (e.g., plantations replacing native forests) caused greater habitat loss and fragmentation then wildfires alone.

Question 13

Natural Hazards are not a global ecological challenge (humans fault). evidence 3

Answer 13

In a paper that aimed to quantify the effect of climate change and land cover change on a range of natural hazards through modelling. Findings showed that human-induced land cover changes are likely to increase natural hazards. Drivers explored were invasive plants, plantation forestry’s and human induced coastal hardening.

Question 14

Global fisheries are a global ecological challenge. evidence 1

Answer 14

In a meta-analysis investigating the rapid worldwide depletion of predatory fish communities’ researchers found 90% of the world’s oceans predatory fishes have been lost. The study attributed this to Industrialized fisheries as they typically reduce community biomass in these ecosystems by 80% within 15 years of exploitation. For example, The Gulf of Thailand lost 60% of large finfish, sharks and skates during the first 5 years of industrialized trawl fishing. Results in trophic cascades.

Question 15

Global fisheries are a global ecological challenge. evidence 2

Answer 15

Large scale industrialised global fisheries are the problem but why? Larger more economically developed countries exploit the developing world. A study quantified mean distance to fishing grounds finding Taiwan, South Korea, Spain, and China rapidly increased their mean distance to fishing grounds by 2000 to 4000 km between 1950 and 2014. Since 1950, heavily subsidized fleets have increased the total fished area from 60% to more than 90% of the world’s oceans.

Question 16

Global fisheries are a global ecological challenge. evidence 3

Answer 16

Industrialised fishing also results in a bycatch. A study used acoustic surveys to count Vaquitas clicking noises and recorded their significant reduction. This bycatch has led to the Vaquita one of the worlds most endangered mammals down to 30. The cause being gillnets used in fishing.

Question 17

Climate Change on our oceans is a global ecological challenge. evidence 1.

Answer 17

Changes in ocean temperature. Marine fish and invertebrates respond to ocean warming through distribution shifts, moving towards higher latitudes and deeper waters. A study looked made a Mean Temperature of Catch MTC index which reflects the average temperature preferences of caught species weighted by annual catch. This study found between 1970 and 2006, global MTC increased by 0.19 °C per decade, and non-tropical regions saw an even faster rise of 0.23 °C per decade. Shows climate change has already affected global fishereries.

Question 18

Climate Change on our oceans is a global ecological challenge. evidence 2.

Answer 18

Change in oxygen content. Warmer water holds less oxygen than colder water. Everything water breathing animals do is limited by ability to obtain O2. A study found that shrinking of fishes exacerbates impacts of global ocean changes. Researchers found body weight of fish is expected to shrink by 14-24% globally due to warmer temperatures and less oxygen.

Question 19

Climate Change on our oceans is a global ecological challenge. evidence 3.

Answer 19

Our oceans are expected to become 150% more acidic by the end of the century. All marine animals that depend on calcium carbonate from shellfish to zooplankton will be affected. A study looked at the effects of acidification on coral reefs finding that corals and the reefs, they build are highly vulnerable. Future corals are expected to have increased bioerosion, reduce growth and calcification and crumbling reef frameworks.

Question 20

Agriculture is a global ecological challenge. evidence 1

Answer 20

Land conversion and habitat loss. The UN food and agricultural organisation database tells us 50% of the worlds habitable land has been converted to farmland. 77% of that land is for livestock with 23% for crops. 17% of the global calorific supply comes from meat and dairy and 83% comes from plant-based food. Global protein supply for global consumption 33% comes from meat and dairy while 67% from plant-based foods.

Question 21

Agriculture is a global ecological challenge. evidence 2

Answer 21

A study used a model to compute global biodiversity loss caused by current land use patterns. They found land use has caused the loss of 15% terrestrial vertebrate species with a risk of global extinction for 556 individual species.

Question 22

Agriculture is a global ecological challenge. evidence 3

Answer 22

Wasteful water consumption. Aral Sea was the world’s 4th largest saline lake. In the 1930s it was decided it would be used to grow cotton. By 1960 millions of acres of land were irrigated using water diverted from the two large rivers that fed the Aral Sea. Now has lost 90% of its volume.

Question 23

Agriculture is a global ecological challenge. evidence 4

Answer 23

Agriculture is degrading soils globally. A study looked at how the intensity of agriculture was affecting soils globally. Researchers found 33% of soils are moderately to highly degraded due to erosion, salinization, acidification, contamination, or compaction and that 52% of agricultural land is already severely affected by soil degradation.

Question 24

Marine Plastic pollution is a global ecological challenge. evidence 1.

Answer 24

Trophic transfer of microplastics. A study tested if microplastics biomagnify through trophic food webs. They found concentration of MPs in top consumers first increased when the concentration of MPs in the environment increased. All functional groups showed significant trophic magnification along with the trophic level. The study concluded that if MPs flowing into the environment can be reduced this will alleviate MP pollution.

Question 25

Marine Plastic pollution is a global ecological challenge. evidence 2.

Answer 25

Marine plastics allow the global dispersal of alien invasive species. A study conducted surveys in two European shellfish culture areas that release rafting alien invasive species. The study found 8 aquaculture related non-native or invasive species attached to marine plastic. Another study found plastic rafting of AIS is also a significant issue in Antarctica. Having brought over a invasive bryozoan species that is ecologically harmful. As Antarctica is also becoming more suitable for establishment by non-native species because of its warming temperatures this will continue to be an issue.

Question 26

Marine Plastic pollution is a global ecological challenge. evidence 3.

Answer 26

Marine plastics can cause disease outbreaks in coral reef communities by promoting microbial colonisation of pathogens. A study looked at 159 coral reefs in the Asia-Pacific region (55.5% of global coral reefs to investigate the effect of plastic waster on the health of reefs. Researchers found the likelihood of disease increased from 4% to 89% when corals were in contact with plastic. 11.1 billion plastic items were entangled on r=coral reefs in this region at the time of this study.

Question 27

Extinctions are a global ecological challenge. evidence 1

Answer 27

A study in Australia found humans rather than climate than climate as the primary cause of Pleistocene megafaunal extinction in Australia. Researchers determined that 85% of the continents large mammal species went extinct around the same time humans first established.

Question 28

Extinctions are a global ecological challenge. evidence 2

Answer 28

In a review that looks at the current trends of population decline and extinction using a sample of 27,600 terrestrial vertebrate species and 177 mammal species. Researchers found the rate of population loss in these species is extremely high. 32% of vertebrate species decreasing in population size and in mammals 40% have experienced sever population decline and over 80% range shrinkage (between 1900-2015). Researchers described this as biological annihilation.

Question 29

Extinctions are a global ecological challenge. evidence 3

Answer 29

Bees an important keystone species for ecosystem services, not only to nature but also agriculture production are heavily under threat. A study found that the Wild bee diversity and number have been declining. Approximately 25% fewer species were found between 2006 and 2015 then before 1990. Wild bees are responsible for pollination of 85% of food crops so this also affects global food security. These results reflect a worldwide decline in bee diversity given that many species are becoming rarer and less likely to be found.

Question 30

What is a threat?

Answer 30

Any process or activity that threatens to destroy or significantly modify the ecological community and/or affect the continuing evolutionary process within any ecological community.

Question 31

GMOs are somewhat a global ecological challenge. Evidence 1

Answer 31

Herbicide tolerant crops are the problem. Glyphosate. In a meta-analytical review that aimed to evaluate the toxicity of glyphosate to bees. Researchers found glyphosate treatments caused significantly higher mortality of bees then controls, with a statistically significant difference (P = 0.0077). Glyphosate is one of the most widely used pesticides in the world and is frequently used with the growing of GMOs. ingestion of glyphosate by bees makes them more susceptible to pathogens and malnutrition. Forager bees can also transfer glyphosate through nectar and pollen and kill other individuals in the colony on return.

Question 32

GMOs are somewhat a global ecological challenge. Evidence 2

Answer 32

Insect resistance is a better option that has less harm to biodiversity. Insect resistant crops. A study looked at how insect resistant crops increase beneficial arthropod activity by not using harmful pesticides when growing.

Question 33

GMOs are somewhat a global ecological challenge. Evidence 3

Answer 33

Another study found GM crops support climate change mitigation by reducing greenhouse gases and having higher yields that result in less land use change. Wider adoption of already-existing GM crops in Europe could result in a reduction equivalent to 7.5% of the total agricultural GHG emissions of Europe.