P7: Kelp Forests

Question 1

Intro- importance of kelp forests

Answer 1

Unintended human consequences are responsible for the changing distribution abundance and biomass of kelp forest. This is particularly concerning given that kelp forests are keystone species which play an important role in carbon cycling; where by they draw carbon into the oceans, making organic carbon from CO2. they also provide important structure habitat for many other species, covering ¼ of global habitats, dominating mainly rocky shorelines.

Question 2

Anthropogenic impacts: hunting of sea otters.

Answer 2

Anthropogenic impacts have contributed to these keystone species declining at an alarming rate. For example, the removal of sea otters from overhunting has caused population expansions of sea urchins (prey) and therefore declining kelp forests abundance given that they are being consumed by more sea urchins

Question 3

Anthropogenic impacts: harvesting and population expansion

Answer 3

Kelp forest are also highly desirable commodity, and therefore are endangered by harvesting. For example brown seaweed cultivation has on average increased by 10.9% annually between 1950 - 2019. Humans are also threatening kelp forests through urban expansion which has driven increased water pollution (FAO, 2021)

Question 4

Anthropogenic impacts: climate change

Answer 4

Finally, climate change is altering and accentuating climatic variables (such as sea water temperatures and storm frequency) causing ecological changes in kelp forest structures and functions. Global warming is changing the distribution of kelp species, with a shift cold water adapted kelp species to warmer water species. these warmer water species decay faster and have slower rates of carbon sequestration. Therefore making kelp forests less effective at buffering the impacts of climate change (Smale, 2020)

Question 5

Effective restoration

Answer 5

transplant, grazing control and reefing are all effective solutions for restoring kelp forest (Eger et al., 2022).

Question 6

Solution: sea otter reintroduction

Answer 6

reintroducing otters back into the system can help kelp forest regrowth and recovery causing a trophic cascade, supporting population increases in most other species except large benthic invertebrates. Eger et al (2022) found kelp forest declines are linked to the persecution of sea otters, therefore protection from persecution could be an important step in the reintroduction.

Question 7

Solution: sustainable harvesting

Answer 7

sustainable harvesting is an important solution to maintaining kelp forests.