Review for "Greater local diversity under older species pools may arise from enhanced competitive equivalence"

2010 ◽  
Vol 20 (2) ◽  
pp. 251-259 ◽  
Author(s):  
Martin Zobel ◽  
Rüdiger Otto ◽  
Lauri Laanisto ◽  
Agustín Naranjo-Cigala ◽  
Meelis Pärtel ◽  
...  

2020 ◽  
Author(s):  
Devin R. Leopold ◽  
Tadashi Fukami

AbstractLocal ecological communities tend to contain more species when they are located within a geologically older region, a pattern that has traditionally been attributed to the accumulation of species in the regional species pool. In this explanation, local species interactions are assumed to play a minor role in the formation of the regional species pool, which is instead thought to be driven by speciation and dispersal occurring across larger areas. Here, we provide evidence suggesting a more important role of local species interactions than generally assumed. In an experiment in which we assembled 320 local communities of root-associated fungi under 80 species pools, we varied the species richness of the experimental species pools and the mean age of the sites from which we collected the fungal species across a 4-myr soil chronosequence in Hawaii. We found that realized local species diversity in the assembled communities increased more extensively with increasing species-pool richness when species were from older sites. We also found that older species pools had lower functional and phylogenetic diversity, indicating that the evolution of greater competitive equivalence among potential colonists enabled higher local diversity under older species pools. Our results suggest that the tendency of older regions to have higher local richness arises not simply because older species pools are more speciose, but also because the constituent species have evolved traits that allow them to co-occur more readily in local communities.


2007 ◽  
Vol 41 (2) ◽  
pp. 193-216 ◽  
Author(s):  
Natasha Borges Sugiyama

Brazil's democratic constitution granted municipalities responsibility to design and implement social policies, allowing for tailored programs to meet local constituent demands. Yet instead of pursuing local diversity, many governments chose to emulate programs made famous elsewhere. What explains the diffusion of social programs across Brazil? This article investigates whether policy makers are motivated by political self-interest, ideology, or socialized norms. It draws on an event history analysis of two innovative programs that have diffused throughout Brazil's largest cities: Bolsa Escola, an education program, and Programa Saúde da Família, a family health program. The author argues that political incentives, such as electoral competition, cannot explain diffusion. Rather, diffusion occurs when left-of-center mayors are ideologically compelled to enact these programs and when public officials with connections to professional networks are socialized to follow professional norms.


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