01942naa a2200253 a 450000100080000000500110000800800410001902400360006010000180009624501160011426000090023052011480023965000280138765000280141565300290144365300120147265300120148465300210149665300220151765300230153970000190156270000210158177300860160220043862015-04-27       2014    bl uuuu     u00u1 u    #d7 a10.4336/2014.pfb.34.80.6342DOI1 aMANZAN, M. F.  aSpatial pattern analysis and demography of two tropical trees in the Brazilian Caatinga.h[electronic resource]  c2014  aAspidosperma pyrifolium (Apocynaceae) and Caesalpinia pyramidalis (Fabaceae) share the same habitat in the Brazilian Caatinga domain. In this paper, we investigate the intra and inter-species interactions between these two plants using spatial pattern analysis among cohorts. The results showed that the adult trees of each species present higher densities at distances shorter than 9 m to 12 m. However, due to seed dispersal via autochory, we expected a more aggregate density for C. pyramidalis than A. pyrifolium as the later disperses seeds through anemochory. Difference in spatial aggregation among cohorts was not observed and therefore the results contradict the expectations of the Janzen-Connell hypothesis. It is likely that this is associated with anthropogenic factors in the past such as fire, animal husbandry and logging. Using a bivariate analysis of the neighborhood density, we also confirmed the significant coexistence between the two species. This coexistence could be explained by the process of positive interspecific interactions, such as facilitation, which is common in semi-arid regions under stressful conditions.  aAspidosperma Pyrifolium  aCaesalpinia Pyramidalis  aCoexistência de plantas  aCohorts  aCoortes  aPadrão espacial  aPlant coexistence  aSpatial patterning1 aFAJARDO, C. G.1 aVIEIRA, F. de A.  tPesquisa Florestal Brasileira, Colombogv. 34, n. 80, p. 331-336, out./dez. 2014.