Ecological resilience in the face of catastrophic damage: The case of Hurricane Maria in Puerto Rico

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/139075/1/nrm12149.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/139075/2/nrm12149_am.pd

The Competitive Structure of Communities: An Experimental Approach with Protozoa

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/119089/1/ecy1969503362.pd

On the Covariance of the Community Matrix

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/119085/1/ecy1972531187.pd

Spatial Pattern And Ecological Process In The Coffee Agroforestry System

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/116922/1/ecy2008894915.pd

Stabilizing intransitive loops: self‐organized spatial structure and disjoint time frames in the coffee agroecosystem

It is familiar knowledge that population dynamics occur in both time and space. In this work, we incorporate three distinct but related theoretical schemata to qualitatively interrogate the complicated structure of part of a real agroecosystem. The three schemata are first, local dynamics translated into intransitive oscillators through spatial movement, second, stabilizing the system through spatial pattern, and third, formation of a self‐organized spatial pattern. The real system is the well‐studied autonomous pest control in the coffee agroecosystem, in which five insect species (one of which is a pest) are involved in creating a complex community structure that keeps the pest under control (the five species are an ant, Azteca sericeasur, a phorid fly parasitoid, Pseudacteon sp., a hymenopteran parasitoid, Coccophagus sp., a beetle predator, Azya orbigera, and the pest itself, the green coffee scale, Coccus viridis). We use the qualitative framing of the three theoretical schemata to develop a cellular automata model that casts the basic predator/prey (natural enemy/pest) system as an intransitive oscillator, and then explore the interaction of the two basic predator/prey systems as coupled oscillators within this model framework. We note that Gause’s principle of competitive exclusion is not violated with this basic framing (i.e., the two control agents cannot coexist theoretically), but that with a change in the spatial structure of the background habitat, coexistence can be maintained through the tradeoff between regional dispersal and local consumption. Finally, we explore how the other oscillator in the system (the ant and its phorid parasitoid) can act as a pilot system, creating the spatial structure in which the other two oscillators operate, but only in the context of disjoint time frames (between the two control agents and the pilot subsystem).Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/146945/1/ecs22489.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/146945/2/ecs22489_am.pd

The ghost of ecology in chaos, combining intransitive and higher order effects

Historically, musings about the structure of ecological communities has revolved around the structure of pairwise interactions, competition, predation, mutualism, etc. . . Recently a growing literature acknowledges that the baseline assumption that the pair of species is not necessarily the metaphorical molecule of community ecology, and that certain structures containing three or more species may not be usefully divisible into pairwise components. Two examples are intransitive competition (species A dominates species B dominates species C dominates species A), and nonlinear higher-order effects. While these two processes have been discussed extensively, the explicit analysis of how the two of them behave when simultaneously part of the same dynamic system has not yet appeared in the literature. A concrete situation exists on coffee farms in Puerto Rico in which three ant species, at least on some farms, form an intransitive competitive triplet, and that triplet is strongly influenced, nonlinearly, by a fly parasitoid that modifies the competitive ability of one of the species in the triplet. Using this arrangement as a template we explore the dynamical consequences with a simple ODE model. Results are complicated and include include alternative periodic and chaotic attractors. The qualitative structures of those complications, however, may be retrieved easily from a reflection on the basic natural history of the system.Comment: 29 pages, 15 figure

Biodiversity Conservation in Tropical Agroecosystems

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/74765/1/annals.1439.011.pd