Why is biodiversity so important? - Kim Preshoff — Transcript

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1. 0:06Our planet's diverse thriving ecosystems may seem like permanent fixtures,
2. 0:11but they're actually vulnerable to collapse.
3. 0:15Jungles can become deserts,
4. 0:17and reefs can become lifeless rocks,
5. 0:19even without cataclysmic events, like volcanoes and asteroids.
6. 0:23What makes one ecosystem strong and another weak in the face of change?
7. 0:28The answer, to a large extent, is biodiversity.
8. 0:32Biodiversity is built out of three intertwined features:
9. 0:35ecosystem diversity,
10. 0:37species diversity,
11. 0:39and genetic diversity.
12. 0:41The more intertwining there is between these features,
13. 0:44the denser and more resilient the weave becomes.
14. 0:48Take the Amazon rainforest,
15. 0:50one of the most biodiverse regions on Earth
16. 0:53due to its complex ecosystems,
17. 0:55huge mix of species,
18. 0:57and the genetic variety within those species.
19. 0:59Here are tangled liana vines,
20. 1:01which crawl up from the forest floor to the canopy,
21. 1:04intertwining with treetops
22. 1:07and growing thick wooden stems that support these towering trees.
23. 1:11Helped along by the vines,
24. 1:13trees provide the seeds, fruits and leaves to herbivores,
25. 1:16such as the tapir and the agouti,
26. 1:19which disperse their seeds throughout the forest so they can grow.
27. 1:23Leftovers are consumed by the millions of insects
28. 1:26that decompose and recycle nutrients to create rich soil.
29. 1:30The rainforest is a huge system filled with many smaller systems, like this,
30. 1:34each packed with interconnected species.
31. 1:38Every link provides stability to the next,
32. 1:40strengthening biodiversity's weave.
33. 1:43That weave is further reinforced
34. 1:45by the genetic diversity within individual species,
35. 1:48which allows them to cope with changes.
36. 1:51Species that lack genetic diversity due to isolation
37. 1:54or low population numbers,
38. 1:56are much more vulnerable to fluctuations
39. 1:58caused by climate change, disease or habitat fragmentation.
40. 2:03Whenever a species disappears because of its weakened gene pool,
41. 2:06a knot is untied and parts of the net disintegrate.
42. 2:10So, what if we were to remove one species from the rainforest?
43. 2:14Would the system fall apart?
44. 2:16Probably not.
45. 2:18The volume of species,
46. 2:19their genetic diversity,
47. 2:21and the complexity of the ecosystems
48. 2:23form such rich biodiversity in this forest
49. 2:26that one species gap in the weave won't cause it to unravel.
50. 2:30The forest can stay resilient and recover from change.
51. 2:34But that's not true in every case.
52. 2:36In some environments, taking away just one important component
53. 2:40can undermine the entire system.
54. 2:42Take coral reefs, for instance.
55. 2:44Many organisms in a reef are dependent on the coral.
56. 2:48It provides key microhabitats, shelter and breeding grounds
57. 2:51for thousand of species of fish, crustaceans and mollusks.
58. 2:56Corals also form interdependent relationships with fungi and bacteria.
59. 3:01The coral itself is a loom
60. 3:02that allows the tangled net of biodiversity to be woven.
61. 3:07That makes coral a keystone organism,
62. 3:09one that many others depend on for their suvival.
63. 3:12So what happens when destructive fishing practices,
64. 3:15pollution and ocean acidification
65. 3:18weaken coral or even kill it altogether?
66. 3:21Exactly what you might think.
67. 3:23The loss of this keystone species leaves its dependents at a loss, too,
68. 3:28threatening the entire fabric of the reef.
69. 3:31Ecosystem, species and genetic diversity
70. 3:34together form the complex tangled weave of biodiversity
71. 3:37that is vital for the survival of organisms on Earth.
72. 3:41We humans are woven into this biodiversity, too.
73. 3:44When just a few strands are lost,
74. 3:46our own well-being is threatened.
75. 3:49Cut too many links, and we risk unraveling it all.
76. 3:52What the future brings is unpredictable,
77. 3:55but biodiversity can give us an insurance policy,
78. 3:58Earth's own safety net to safeguard our survival.