Genomic Insights into the Historical Population Dynamics and Spatial Differentiation of an Endangered Island Endemic Palm, Brahea edulis

2021 ◽  
Vol 182 (8) ◽  
pp. 695-711
Author(s):  
Anastasia Klimova ◽  
Alfredo Ortega-Rubio ◽  
Neftalí Gutiérrez-Rivera ◽  
Pedro P. Garcillán
Keyword(s):  
Population Dynamics ◽  
Spatial Differentiation ◽  
Island Endemic

scholarly journals Inter-island transfers and population dynamics of Seychelles Warblers Acrocephalus sechellensis

1997 ◽  
Vol 7 (1) ◽  
pp. 7-26 ◽  
Author(s):  
Jan Komdeur
Keyword(s):  
Population Dynamics ◽  
First Year ◽  
Territory Quality ◽  
Island Endemic ◽  
Breeding Populations ◽  
Suitable Space ◽  
Seychelles Warbler ◽  
Successful Establishment ◽  
Term Management

SummaryIn the 1950s the Seychelles Warbler Acrocephalus sechellensis was a highly threatened single-island endemic species with a population of 26 individuals confined to Cousin Island in the inner Seychelles. Following long-term management of Cousin, the population steadily recovered to around 300–360 birds. In order to give the species the security of additional breeding populations, some warblers were successfully transferred to the islands of Aride and Cousine in September 1988 and June 1990 respectively. During the three years after the transfer to Aride and the first year after the transfer to Cousine, mean territory quality (measured as insect prey available) on these islands was significantly higher than that on Cousin, leading to higher reproductive success per territory and survival of juveniles and adult birds. In November 1991, all transferred birds were still alive, and 205 young had fledged successfully, bringing the total warbler population to c.585 birds. By then there was enough suitable space still remaining on Aride and Cousine for young birds to establish territories and the rise in warbler numbers is expected to continue. The successful establishment of three self-sustaining and viable breeding populations has ensured that the Seychelles Warbler is no longer a globally threatened species.

scholarly journals Advantages of the division of labour for the long-term population dynamics of cyanobacteria at different latitudes

2012 ◽  
Vol 279 (1742) ◽  
pp. 3457-3466 ◽  
Author(s):  
Valentina Rossetti ◽  
Homayoun C. Bagheri
Keyword(s):  
Population Dynamics ◽  
Circadian Rhythm ◽  
Population Size ◽  
Biomass Production ◽  
Carbon Fixation ◽  
Spatial Differentiation ◽  
Biomass Accumulation ◽  
Division Of Labour ◽  
Cyanobacterial Blooms ◽  
Competition For Light

A fundamental advancement in the evolution of complexity is division of labour. This implies a partition of tasks among cells, either spatially through cellular differentiation, or temporally via a circadian rhythm. Cyanobacteria often employ either spatial differentiation or a circadian rhythm in order to separate the chemically incompatible processes of nitrogen fixation and photosynthesis. We present a theoretical framework to assess the advantages in terms of biomass production and population size for three species types: terminally differentiated (heterocystous), circadian, and an idealized species in which nitrogen and carbon fixation occur without biochemical constraints. On the basis of real solar irradiance data at different latitudes, we simulate population dynamics in isolation and in competition for light over a period of 40 years. Our results show that in isolation and regardless of latitude, the biomass of heterocystous cyanobacteria that optimally invest resources is comparable to that of the idealized unconstrained species. Hence, spatial division of labour overcomes biochemical constraints and enhances biomass production. In the circadian case, the strict temporal task separation modelled here hinders high biomass production in comparison with the heterocystous species. However, circadian species are found to be successful in competition for light whenever their resource investment prevents a waste of fixed nitrogen more effectively than do heterocystous species. In addition, we show the existence of a trade-off between population size and biomass accumulation, whereby each species can optimally invest resources to be proficient in biomass production or population growth, but not necessarily both. Finally, the model produces chaotic dynamics for population size, which is relevant to the study of cyanobacterial blooms.

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