Annual mass drownings of the Serengeti wildebeest migration influence nutrient cycling and storage in the Mara River.
Proc Natl Acad Sci U S A
; 114(29): 7647-7652, 2017 07 18.
Article
em En
| MEDLINE
| ID: mdl-28630330
ABSTRACT
The annual migration of â¼1.2 million wildebeest (Connochaetes taurinus) through the Serengeti Mara Ecosystem is the largest remaining overland migration in the world. One of the most iconic portions of their migration is crossing of the Mara River, during which thousands drown annually. These mass drownings have been noted, but their frequency, size, and impact on aquatic ecosystems have not been quantified. Here, we estimate the frequency and size of mass drownings in the Mara River and model the fate of carcass nutrients through the river ecosystem. Mass drownings (>100 individuals) occurred in at least 13 of the past 15 y; on average, 6,250 carcasses and 1,100 tons of biomass enter the river each year. Half of a wildebeest carcass dry mass is bone, which takes 7 y to decompose, thus acting as a long-term source of nutrients to the Mara River. Carcass soft tissue decomposes in 2-10 wk, and these nutrients are mineralized by consumers, assimilated by biofilms, transported downstream, or moved back into the terrestrial ecosystem by scavengers. These inputs comprise 34-50% of the assimilated diet of fish when carcasses are present and 7-24% via biofilm on bones after soft tissue decomposition. Our results show a terrestrial animal migration can have large impacts on a river ecosystem, which may influence nutrient cycling and river food webs at decadal time scales. Similar mass drownings may have played an important role in rivers throughout the world when large migratory herds were more common features of the landscape.
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Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Ruminantes
/
Cadeia Alimentar
/
Migração Animal
Tipo de estudo:
Prognostic_studies
Limite:
Animals
País/Região como assunto:
Africa
Idioma:
En
Revista:
Proc Natl Acad Sci U S A
Ano de publicação:
2017
Tipo de documento:
Article