KEYSTONE SPECIES FLAGSHIP SPECIES UMBRELLA SPECIES Core Course

KEYSTONE SPECIES FLAGSHIP SPECIES UMBRELLA SPECIES Core Course No. ZOOA – P 3 T, Group-A, Unit: 2, Topic No. 6

Keystone species

Keystone Species Concept In ecological communities there are little players and big players. The biggest players of all are referred to as keystone species. A central stone at the summit of an arch, locking the whole together. Removal of the keystone in the arch will cause the structure to collapse. A keystone species may be defined as one whose presence/ absence, or increase/decrease in abundance, strongly affects other species in the community and eventually affect the ecosystem.

Indirect Species Interactions • The keystone species effect is the best-known example of indirect interactions. One cannot have a keystone species effect without the presence of indirect interactions. – Keystone species produce strong indirect effects, out of proportion to their abundance. • If a predator strongly suppresses its prey (e. g. , herbivores), one expects the trophic level below (e. g. , plants) to benefit. Such topdown trophic cascades are well-known in lakes. Keystone species have low functional redundancy. This means that if the species were to disappear from the ecosystem, no other species would be able to fill its ecological niche.

Keystone Species Concept Ø The concept was introduced by the zoologist Robert T. Paine in 1969. ØSpecies that have a large effect on an ecosystem ØTake them away and the system collapses Ø Domino Effect

Keystone Predator

Rocky intertidal ecosystem of Makah Bay, Washington In the rocky intertidal zone, mussels are superior are occupying space, crowding out other species. Starfish are effective predators of mussels, and thereby make room for other species.

Starfish as Makah Bay • Keystone • Pisaster ochraceus is an efficient predator of the common mussel, Mytilus californicus. • It reduces abundance of M. californicus, allowing other macroinvertebrates to persist. • If Pisaster present = diverse intertidal community.

Dr. Robert T. Paine’s Work With Pisaster (control) Number of species present 20 15 10 Without Pisaster (experimental) 5 0 1963 ´ 64 (a) The sea star Pisaster ochraceous feeds preferentially on mussels but will consume other invertebrates. ´ 65 ´ 66 ´ 67 ´ 68 ´ 69 ´ 70 ´ 71 ´ 72 (b) When Pisaster was removed from an intertidal zone, mussels eventually took over the rock face and eliminated most other invertebrates and algae. In a control area from which Pisaster was not removed, there was little change in species diversity. ´ 73

Starfish as Keystone Predators A starfish removal experiment in Washington State demonstrated that the mussels are competitive dominants. Starfish predation opens up enough space for various barnacles, echinoderms and other marine invertebrate species to maintain a presence. When starfish are experimentally removed, mussels take over and other species are excluded. A hoard of hungry starfish converge on a mussel bed. A starfish curls its body around the mussel, using its tube feet to pry apart the valves enough to insert its extensible stomach. Digestive enzymes break down the mussels’ muscles, and the starfish consumes its prey.

The case of the Californian sea otter

Kelp forests • Sea otters eat sea urchins • Sea urchins eat kelp • Kelp forests act as ecosystems for many species and as nurseries for young fish • Hunting sea otters for fur impacted on the kelp forest ecosystems. Sea urchins eating kelp

The wolves of Yellowstone Park • Montana, Wyoming, and Idaho States of US • Grey wolves (Canis lupus) were considered a pest species • Hunted throughout western US • Exterminated from Yellowstone 1926

The consequences • • Wolves hunt elk Elk populations increase Forest cover decreases Decrease in wetlands North American Elk (Cervus elaphus) Wolves are reintroduced in 1990

Keystone Herbivores

African Elephants of Serengeti plains in Tanzania Elephants eat shrubs and small trees Grasses thrive and sustain grazing animals such as antelopes, wildebeests, and zebras Maintain the savanna grassland Smaller animals such as mice and shrews are able to burrow in the warm, dry soil of a savanna Predators such as lions and hyenas depend on the savanna for prey.

Keystone Mutualists

Green-backed firecrowns woody grasslands of Patagonia, South America

Umbrella Species

Characteristics ØA large species on which other species are dependent. Similar to keystone species. ØUmbrella species are usually migratory and need a large habitat. ØAs the term implies, a species casts an “umbrella” over the other species (protect them and their habitat) by being more or equally sensitive to habitat changes. ØThus monitoring this one species and managing for its continued success results in the maintenance of high quality habitat for the other species in the area.

Characteristics Umbrella species can be both plants and animals species with either of the species offering protection to the other. Most of the umbrella species are listed as endangered or threatened on the IUCN Red List, and therefore their conservation extends to the conservation of their habitat.

Examples Some of the notable umbrella species include spotted owl whose conservation protects the old growth trees the conservation of both species has led to the protection of mollusks and salamanders within the protective boundary The protection of the Bay checkerspot butterfly automatically leads to the protection of the grassland Amur tiger in the Russian Far East also means an automatic conservation and protection of the deer and boar in their habitat. The protection of canebrake offers further protection to broader species within its habitat because of the umbrella effect. Elephants

Flagship Species

Characteristics ØA flagship species is a species selected to act as an ambassador, icon or symbol for a defined habitat, issue, campaign or environmental cause. ØBy focusing on, and achieving conservation of that species, the status of many other species which share its habitat – or are vulnerable to the same threats - may also be improved. ØFlagship species are usually relatively large, and considered to be 'charismatic' in western cultures. ØFlagship species may or may not be keystone species and may or may not be good indicator of biological process.

Categories Of Flagship Species q. International q. Cultural q. Ecological Malagasy Baobab, Madagaskar

Benefits of Flagship Species v. This added revenue enables the proper mechanisms to be put in place for protection and sustainability of the species, which in turn is intended to trickle down to encourage the improvement of the other species coexisting with them. v. Flagship species often tend to be aesthetically attractive in order to capture the attention of the public. v. Improve the public attitude towards biodiversity conservation.