
@article {99939,
	title = {Large herbivores suppress liana infestation in an African savanna.},
	journal = {Proc Natl Acad Sci U S A},
	volume = {118},
	year = {2021},
	month = {2021 Oct 12},
	abstract = {<p>African savannas are the last stronghold of diverse large-mammal communities, and a major focus of savanna ecology is to understand how these animals affect the relative abundance of trees and grasses. However, savannas support diverse plant life-forms, and human-induced changes in large-herbivore assemblages-declining wildlife populations and their displacement by livestock-may cause unexpected shifts in plant community composition. We investigated how herbivory affects the prevalence of lianas (woody vines) and their impact on trees in an East African savanna. Although scarce (\&lt;2\% of tree canopy area) and defended by toxic latex, the dominant liana, (Apocynaceae), was eaten by 15 wild large-herbivore species and was consumed in bulk by native browsers during experimental cafeteria trials. In contrast, domesticated ungulates rarely ate lianas. When we experimentally excluded all large herbivores for periods of 8 to 17 y (simulating extirpation), liana abundance increased dramatically, with up to 75\% of trees infested. Piecewise exclusion of different-sized herbivores revealed functional complementarity among size classes in suppressing lianas. Liana infestation reduced tree growth and reproduction, but herbivores quickly cleared lianas from trees after the removal of 18-y-old exclosure fences (simulating rewilding). A simple model of liana contagion showed that, without herbivores, the long-term equilibrium could be either endemic (liana-tree coexistence) or an all-liana alternative stable state. We conclude that ongoing declines of wild large-herbivore populations will disrupt the structure and functioning of many African savannas in ways that have received little attention and that may not be mitigated by replacing wildlife with livestock.</p>
},
	issn = {1091-6490},
	doi = {10.1073/pnas.2101676118},
	author = {Coverdale, Tyler C and O{\textquoteright}Connell, Ryan D and Hutchinson, Matthew C and Savagian, Amanda and Kartzinel, Tyler R and Palmer, Todd M and Goheen, Jacob R and Augustine, David J and Sankaran, Mahesh and Tarnita, Corina E and Pringle, Robert M}
}
@article {17523,
	title = {Farming and public goods production in Caenorhabditis elegans populations.},
	journal = {Proc Natl Acad Sci U S A},
	volume = {114},
	year = {2017},
	month = {2017 Feb 28},
	pages = {2289-2294},
	abstract = {<p>The ecological and evolutionary dynamics of populations are shaped by the strategies they use to produce and use resources. However, our understanding of the interplay between the genetic, behavioral, and environmental factors driving these strategies is limited. Here, we report on a Caenorhabditis elegans-Escherichia coli (worm-bacteria) experimental system in which the worm-foraging behavior leads to a redistribution of the bacterial food source, resulting in a growth advantage for both organisms, similar to that achieved via farming. We show experimentally and theoretically that the increased resource growth represents a public good that can benefit all other consumers, regardless of whether or not they are producers. Mutant worms that cannot farm bacteria benefit from farming by other worms in direct proportion to the fraction of farmers in the worm population. The farming behavior can therefore be exploited if it is associated with either energetic or survival costs. However, when the individuals compete for resources with their own type, these costs can result in an increased population density. Altogether, our findings reveal a previously unrecognized mechanism of public good production resulting from the foraging behavior of C. elegans, which has important population-level consequences. This powerful system may provide broad insight into exploration-exploitation tradeoffs, the resultant ecoevolutionary dynamics, and the underlying genetic and neurobehavioral driving forces of multispecies interactions.</p>
},
	issn = {1091-6490},
	doi = {10.1073/pnas.1608961114},
	author = {Thutupalli, Shashi and Uppaluri, Sravanti and Constable, George W A and Levin, Simon A and Stone, Howard A and Tarnita, Corina E and Brangwynne, Clifford P}
}
