The Iubs-Scope-Unesco Program of Research in Biodiversity.

A planning workshop was called by IUBS (the International Union of Biological Sciences) at the Harvard Forest to develop an international research program in biodiversity, including the inventorying and monitoring of the world's biological diversity. Workshop participants were asked to develop research hypotheses that answer aspects of the question "What is the importance of biodiversity for the proper functioning of biological systems, from populations to ecosystems?" The hypotheses developed dealt with the changes that might be expected in biodiversity as a result of anthropogenic activity and also the complementary issue of how changes in biodiversity will affect the functioning of biological systems. Habitat fragmentation, loss and addition of species, changes in the functional and structural attributes of ecosystems, and the ability of depauperate ecosystems to respond to climatic and other changes, were addressed.

ENVIRONMENTAL AND GENETIC DETERMINANTS OF PLANT SIZE IN VIOLA SORORIA.

Survivorship and fecundity in the forest herb, Viola sororia, are size-dependent. The basis of size variation among individuals of Viola sororia was investigated with a uniform environment experiment. Plants collected from natural populations were vegetatively reproduced and grown under two light regimes in a greenhouse.

The meaning and measurement of size hierarchies in plant populations.

The term "size hierarchy" has been used frequently by plant population biologists but it has not been defined. Positive skewness of the size distribution, which has been used to evaluate size hierarchies, is inappropriate. We suggest that size hierarchy is equivalent to size inequality.

Shoot demography in new England populations of Maianthemum canadense desf.

The demography of shoots of eight populations of a herbaceous perennial exhibiting clonal growth, is presented. The study was done along an elevational gradient, from a more open secondary mixed forest to a denser, more mature stand. Most shoots lived one to three years on the average, but shoots as old as twelve years were found.