3.4 Species-Based Conservation Strategies
Species-Based Conservation Strategies
This links back to 3.3 Conservation Case Studies and the final case study which asks students to examine a species which has been in recovery. Endangered Species in Recovery. These species have usually had a species-based conservation strategy employed such as captive breeding, the use of CITES for protection, and are often "charasmatic" species which help protect entire ecosystems. I don't believe students need to know a lot of detail about the strategies listed in the Guide, simply an overview and some examples of how they can be applied and their value and drawbacks.
The way I like to tackle this section, is to have students watch a variety of videos and then lead a discussion about these species based conservation strategies. A useful tool would be to use the visible thinking routine, "See, Think, Wonder".
- There are various approaches to the conservation of biodiversity, each with associated strengths and limitations.
Recommended Teaching Time (not including practicals): 1 hour
From the Guide (IB ESS Guide 2015)
- Conservation approaches include habitat conservation, species-based conservation and a mixed approach.
- Alternative approaches to the development of protected areas are species-based conservation strategies including:
- captive breeding and reintroduction programmes, and zoos
- selection of “charismatic” species to help protect others in an area (flagship species)
- selection of keystone species to protect the integrity of the food web.
Watch one, or a selection of videos, for about 20 minutes. Be prepared to explain to your classmates what you Saw, Thought and Wondered about the films.
CITES (Convention on International Trade in Endangered Species of Wild Fauna and Flora) was agreed in 1973 and came into force in 1975. By 2009, 175 party states had signed up to the agreement.
It aims to prevent species threatened with extinction because of international trade. Parties act by banning commercial international trade in an agreed list of endangered species (Appendix-I listed species) and by regulating and monitoring trade in others that might become endangered or whose trade needs to be regulated to ensure control over trade in Appendix-I species (Appendix-II listed species).
The image is a pangolin, recently added to Appendix 1, the most strict protection the convention can offer. You can read about the terrible trials that have been facing in this Guardian article reporting the success of the CITES negotiations in 2016.
Roughly 5,000 species of animals and 29,000 species of plants are protected by CITES against over-exploitation through international trade.
Although CITES has certainly not solved the problem completely, it has made it much more difficult to continue the international trade in endangered species, and it is regarded as an important step in the right direction.
Meeting these demands can place a substantial burden on governments, particularly those with limited resources, and work is proceeding on harmonising information management among the treaties. The negotiation of which species are listed in CITES is a very political process with countries protecting/advocating for their own interests, sometimes against the greater conservation of that species.
Many endangered species are highly prized by collectors, as rarity increases value. This has significantly increased the tendency for poachers to find ways of hunting, capturing and selling their quarry illegally without being detected. Ultimately the trade in endangered species will be controlled by a combination of demand management and supply management. Demand management involves trying to dissuade people from wanting to buy endangered wildlife products. Supply management involves controlling which wildlife products are available in the marketplace.
Demand management would be exemplified by the campaign by leading chefs and celebrities to demonise shark fin soup, while supply management would be the addition of shark species to CITES.
Here is his documentary. (It is about 47 minutes)
A short video introducing CITES (just under 3 minutes):
Captive Breeding Programmes
For the most endangered species there are few viable alternatives to captive breeding programmes. These are designed to try to save what survives, ideally for subsequent release back into the wild. In extreme situations, the species may actually be extinct in the wild. Przwalsky’s Horse was almost extinct in it’s native area of the Mongolia and Asian Steppes. A group of concerned scientists, captured all the remaining individuals and developed a captive breeding programme, eventually reintroducing the Horses to their ranges. This sort of programme will only work if the reason for the organisms extinction no longer exists.
To read more about Przwalsky's Horse try this Scientific American blog post. This short video (about 6 minutes) gives more background.
The Panda has a very active captive breeding programme but success in saving the species will only work if the large stretches of habitat required for the panda are preserved.
Another problem with captive breeding programmes is that the genetic base for the captive population is very small, e.g. Mexican Gray Wolf, the initial population consisted of four males and one female. In early attempts at captive breeding, with very small populations where breeding was not carefully planned inbreeding depression quickly set in and genetic diseases started occurring. By changing the programme so that the original male no longer bred with his daughters and through this careful planning the programme succeeded.
Basel Zoo in Switzerland is involved in a breeding programme to save Asian rhinos.
Zoos and Botanic Gardens
Zoos and Botanical Gardens have developed an important role in the conservation of wildlife. Originally these establishments were there to preserve and present the exotic, allowing their study by naturalists and scientists. Over time they have become a repository of endangered organisms and involved in the breeding programmes of these organisms.
Some people view zoos as prisons with a lack of dignity, freedom and quality of life, but conditions have largely improved with zoos refocusing their resources and objectives towards the conservation of species, retaining, perhaps fewer species, in better conditions. Also Zoos and Botanical Gardens form giant networks where organisms can be loaned or swapped in order to maintain a larger genetic base for captive breeding programmes.
Here's some more examples of the roles that zoos and botanic gardens can play in conservation.
Oakland Zoo and California Condors (about 5 minutes)
The Role of Kew Botanic Gardens (4 minutes)
The History of the Herbarium at Kew (2 minutes)
Plants back from the Brink (4 minutes 20 sec)
Charasmatic and Flagship Species
Often in the fight for the conservation, focus is laid on a particular species. This species may be a keystone species for a particular ecosystem, it may be endangered and it often will be an aesthetically pleasing species, e.g. tiger, panda or elephant. By focussing on one particular species, habitats are saved for many species, perhaps, less “sexy” species, but still essential for the functioning of that ecosystem. For example, in Mudumalai Nature Reserve, large areas of teak have been replanted in order to provide suitable habitat for elephants. Without the teak forests the elephants would be less likely to prosper but the reserve signs and adverts say “Elephant Reserve” not “Teak Forest”. Similarly many areas of habitat are being set aside to protect the tiger but this also maintains the habitat for other species.
In the Western Ghats, grasslands form important parts of the watershed, but the focus is on the Nilghiri Tahr. By saving these ecosystems for the Tahr, many other species are saved.
Technically it is better to save an area rather than focussing on a species but taking the species approach serves a useful purpose with the same end result.
A keystone species plays a much larger role in maintaining the structure of an ecosystems than other species. Nature has a nice summary of the scientific studies to understand this.
A very successful strategy can be to determine if a particular species is a keystone species in an ecosystem. Be focussing on this species, trophic cascades can occur and the system restorred to an equilibrium. See Equilibrium and Feedback Loops and the re-introductio of wolves into Yellowstone National Park.
For a great overview of keystone species watch this video (20 minutes) from HHMI Biointeractive and Sean Carroll.
Describe three species based approaches to conservation. Explain the strengths and weaknesses of these strategies.
- ^ http://www.mexicanwolves.org/index.php/captive-breeding