Species Diversity and Diversity Profiles: Concept, Measurement, and Application to Timber and Range Management

Abstract

The concepta 8nd m of sevcnl diversity 8ssessments 8re presented 8nd 8ppiied to 8 pnctierl situ8tion. Burning, mech8niul methods of site prepurtion, rad c8ttie pizing ire common dis-turb8nces in forest8 of the South. Their influence on pi8nt diversity indices ue exrmined in 8 iongle8f-si8sb pine forat of north Flor-id8. Species richness, Shnnon's index, md Simpson's index showed incrwes in diversity shortly following burning md site prepu8tion 8nd 8 trend towed pre-tre8tment conditions 8fter 6 ye8rs. Deferred-rot8tion gr8zing systems hrd no infkence. Cornpwtive diversity profiles showed simik trends but were more infonnrtive by providing both qaulit8tive md qu8ntit8tive informrtion. These technique8 8re us&11 for newsing community reaponeee to m8n8gement prrctic* th8t is, they 8re effective methods for underst8nding the imp8cts of forest nunrrgement 8nd nnge management pnctices on pleat community structure and succewion. Key Work species richness, Sh8nnon's diversity index, Simp son's diversity index, compurtive diversity profiies, phnt succession, pine-wiregrmss vegetrtion Literature on the mcasurcment of specks diversity is vohnninous. Many indices have been proposed, and there has been much debate concerning their use and meaning. Analogous measurements appear in ecology, genetics, linguistics, information theory, and economics. Fortunately, significant theoretical advances have recently appeared in the ecological literature (e.g. Grassle et al. 1979). Patil and Taillie (1982) proposed a compelling definition of species diversity and showed unified, intuitive motivations for the most popular indices along with their relatedness to measures of rarity. These authors and others (e.g. Solomon 1979, Taillie 1979) introduced concepts of intrinsic diversity orderings. When intrinsic orderings exist between 2 communities, any diversity index will agree with the indicated ordering, so these orderings are index free. Some forest and range management practices (especially clearcut harvesting with intensive site-preparation and range improvement through chopping or discing) conjure vivid images of ecosystem destruction. Hence, many conservation and environmental groups have suggested a need for assessment of the effects of such practices on species diversity. Therefore, we need better tools for assessing and presenting the impacts of management practices on community structure. Indeed, the National Forest Management Act of the United States [Federal Register 44(181), 219.13(6)] requires that managed practices maintain the diversity of forest ecosystems as demonstrated by quantitative comparisons of the diversities of natural and managed forests. The Act is based not only on aesthetic preferences, but on sound biological principles as well-for example, a diverse community represents a larger gene pool, and is less susceptible to devastation by catastrophic events such as pest epidemics. In this paper we analyze recent data from integrated pinegrazing management research to determine trends in species occurrence, cover, and...

Effects of silviculture treatments on vegetation after fire in Pinus halepensis Mill. woodlands (SE Spain)

“…However, in Mediterranean forests, plant communities are well adapted to sunny exposures and the effect produced by a thinning operation can be the opposite. In sites where prescribed fires are used on clear-cuts, diversity value increases during the early stages after silviculture operations, and after a few years, it decreases to the values before perturbation [21].…”

Heterogeneidade altitudinal na Floresta Atlântica setentrional: um estudo de caso no sul da Bahia, Brasil

“…Isto é conseqüência da existência de três espécies predominantes (Cyathea phalerata, Eugenia schottiana e Guapira obtusata) e de uma menor abundância de espécies raras na área 1. Esta análise seguiu a indicação de autores que sugerem a utilização deste método de ordenação da diversidade, pois a utilização de um único índice poderia trazer conclusões incorretas a este respeito (Lewis et al 1988;Kindt et al 2006;Melo 2008).…”

Early vegetation dynamics of Pinus tropicalis Morelet forests after experimental fire (W Cuba)

“…Intolerant plants released from a relatively shaded position to one that is suddenly fully-exposed may show a decrease in growth (cover) or may actually die. In sites where prescribed fires are used on clear-cuts, diversity value increases during the early stages after silviculture operations, and after a few years, it decreases to the values before perturbation [35].…”