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Forest disturbance has been the subject of intense research for many years, but the synergistic effects of various disturbance factors on the forest vegetation are not well documented, particularly in Sal forests. In this thesis, the nexus between a bundle of inherent disturbances of varying intensities and the diversity and/or regeneration of Nepalese Sal forests was examined. In addition, the effects of a single disturbance factor – tree fall gaps – on species diversity, regeneration and early growth of Sal forest were assessed. The intensity of the combined inherent disturbances in each of the studied forest was calculated, and was found to have differing effects on various aspects of the forest vegetation. The total stem density of saplings and poles increased with increasing disturbance intensity, to a certain level, while most of the tree species in the community showed changing dispersion patterns along the disturbance gradient. Socially preferred tree species displayed high regeneration performance in forests subjected to moderate level of disturbance. Tree fall gaps favored regeneration by increasing the density of seedlings of some socially preferred tree species (including Sal) and promoted the maintenance of high species diversity. However, neither overall species diversity nor regeneration positively correlated with gap size, suggesting that the maintenance of species diversity and regeneration in gaps are related more strongly to several other attributes of gaps than gap size. Generally, forests subjected to moderate level of disturbance maintained species diversity and enhanced regeneration performance, which in turn was coupled with the regeneration strategy of dominant tree species – in line with the Intermediate Disturbance and Recruitment Limitation Hypotheses. In conclusion, the findings signify that moderate level of disturbance may be touted as a management tool for Sal forests.

This was one of the five papers out of the ten submitted that was accepted at the Parallel Problem Solving from Nature conference, one of the best evolutionary computation conferences out there. Among its many advantages, it’s published by Springer, and papers are online a few days before the conference. One of the papers accepted was Testing the Intermediate Disturbance Hypothesis: Effect of Asynchronous Population Incorporation on Multi-Deme Evolutionary Algorithms . Here’s the abstract:

In P2P and volunteer computing environments, resources are not always available from the beginning to the end, getting incorporated into the experiment at any moment. Determining the best way of using these resources so that the exploration/exploitation balance is kept and used to its best effect is an important issue. The Intermediate Disturbance Hypothesis states that a moderate population disturbance (in any sense that could affect the population fitness) results in the maximum ecological diversity. In the line of this hypothesis, we will test the effect of incorporation of a second population in a two-population experiment. Experiments performed on two combinatorial optimization problems, MMDP and P-Peaks, show that the highest algorithmic effect is produced if it is done in the middle of the evolution of the first population; starting them at the same time or towards the end yields no improvement or an increase in the number of evaluations needed to reach a solution. This effect is explained in the paper, and ascribed to the intermediate disturbance produced by first-population immigrants in the second population.

Several of the authors attended the conference, and were there, explaining out the poster. A good and nice experience, and I expect our message got through.