title: The influence of microhabitat on the population dynamics of four herbaceous species in a semiarid area of northeastern Brazil.
abstract: Variation in annual rainfall is considered the most important factor influencing population dynamics in dry environments. However, different factors may control population dynamics in different microhabitats. This study recognizes that microhabitat variation may attenuate the influence of climatic seasonality on the population dynamics of herbaceous species in dry forest (Caatinga) areas of Brazil. We evaluated the influence of three microhabitats (flat, rocky and riparian) on the population dynamics of four herbaceous species (Delilia biflora, Commelina obliqua, Phaseolus peduncularis and Euphorbia heterophylla) in a Caatinga (dry forest) fragment at the Experimental Station of the Agronomic Research Institute of Pernambuco in Brazil, over a period of three years. D. biflora, C. obliqua and P. peduncularis were found in all microhabitats, but they were present at low densities in the riparian microhabitat. There was no record of E. heterophylla in the riparian microhabitat. Population size, mortality rates and natality rates varied over time in each microhabitat. This study indicates that different establishment conditions influenced the population size and occurrence of the four species, and it confirms that microhabitat can attenuate the effect of drought stress on mortality during the dry season, but the strength of this attenuator role may vary with time and species.
authors.affiliation: Centro Acadêmico de Vitória, Universidade Federal de Pernambuco, Vitória de Santo Antão, PE, Brazil.
authors.forename: K A
authors.initials: KA
authors.lastname: Silva
authors.affiliation: Laboratório de Ecologia Vegetal dos Ecossistemas Naturais, Universidade Federal Rural de Pernambuco, Recife, PE, Brazil.
authors.forename: J M F F
authors.initials: JM
authors.lastname: Santos
authors.affiliation: Laboratório de Ecologia Vegetal dos Ecossistemas Naturais, Universidade Federal Rural de Pernambuco, Recife, PE, Brazil.
authors.forename: J R
authors.initials: JR
authors.lastname: Andrade
authors.affiliation: Universidade Federal do Piauí, Bom Jesus, PI, Brazil.
authors.forename: E N
authors.initials: EN
authors.lastname: Lima
authors.affiliation: Laboratório de Ecologia Vegetal dos Ecossistemas Naturais, Universidade Federal Rural de Pernambuco, Recife, PE, Brazil.
authors.forename: U P
authors.initials: UP
authors.lastname: Albuquerque
authors.affiliation: Laboratório Sala Verde, Instituto Federal de Pernambuco, Recife, PE, Brazil.
authors.forename: E M N
authors.initials: EM
authors.lastname: Ferraz
authors.affiliation: Laboratório de Ecologia Vegetal dos Ecossistemas Naturais, Universidade Federal Rural de Pernambuco, Recife, PE, Brazil.
authors.forename: E L
authors.initials: EL
authors.lastname: Araújo
mesh_terms: D001938:Brazil; D003889:Desert Climate; D065928:Forests; D019684:Magnoliopsida / Q000502:physiology*; D011156:Population Density; D012621:Seasons; D013045:Species Specificity