in semiarid regions such as saida, the steppe ecosystem is currently submitted to desertification under the combined effect of human activity and climate change. our study is a contribution to the assessment of the biodiversity of steppe formations through a phytoecological diagnosis at the south zone of the wilaya of saida. to achieve the objective of this study, a methodological approach base...

Long-term effects of Lupinus lepidus on vegetation dynamics at Mount St. Helens by Roger del Moral & Lara Rozzell Abstract: The nitrogen-fixing legume Lupinus lepidus is the most abundant herb on recently formed volcanic surfaces at Mount St. Helen. We compared vegetation structure in 30 Lupinus colonies in three age classes (old, mature, or young based on known years of their establishment) to...

a r t i c l e i n f o Spatial observations of plant occurrences contain a wealth of information on relations among species and on the relation between species and environmental conditions. Typically, inventory data of this kind are large co-occurrence matrices, and hence, direct ecological interpretations based on expert knowledge are often very difficult. Hitherto, ordination approaches have b...

Floristic Quality Assessment (FQA) is increasingly influential for making land management decisions, for directing conservation policy, and for research. But, the basic ecological properties and limitations of its metrics are ill defined and not well understood-especially those related to sample methods and scale. Nested plot data from a remnant tallgrass prairie sampled annually over a 12-year...

McMichael et al state that we overlooked the effects of post-Columbian human activities in shaping current floristic patterns in Amazonian forests. We formally show that post-Columbian human influences on Amazonian forests are indeed important, but they have played a smaller role when compared to the persistent effects of pre-Columbian human activities on current forest composition.

Six floristic communities are described from rainforest in northern and eastern Tasmania. The communities occur in lower rainfall areas, where they are often restricted ro fire-protected sites. They have climatic envelopes which are significantly distinct from each other and from rainforest in higher rainfall areas. The conservation status of the communities is assessed.