Relações clima-crescimento de uma espécie nativa e uma invasora ao longo de um gradiente de aridez: uma análise dendrocronológica buscando compreender o sucesso de invasão

Abstract

The establishment of invasive species results in a reduction in native biodiversity. The invasiveness characteristics of the species and of the receptor ecosystems confer competitive advantages for invasive success in new introduction environments. The highly competitive capacity of invasive exotic species is attributed to their faster and greater growth (plasticity) compared to native species. However, the methodologies used may distort the interpretation that invasive species are superior competitors to native species, since measuring biomass at the end of the experiment does not consider how resource dynamics may affect species growth. Therefore, this study aimed to investigate the influences of climatic conditions on the growth performance of an invasive and a native species along an aridity gradient in the semi-arid domain of the Caatinga. To this end, we analyzed the growth rings of the invasive Cryptostegia madagascariensis and the native Cobretum leprosum, which are co-occurring species in the coastal region of the state of Ceará and have similar growth patterns. Subsequently, we analyzed the effects of local and regional climatic factors on the growth of both species. Both species showed annual growth rings. The populations had a short life cycle within the invaded community (ages ≤ 20 years). There are no differences between the growth of invasive and native species. However, the growth of species responded negatively to climatic factors. The native species is affected by rising temperatures along the gradient. El Niño negatively affects the growth of native species with greater intensity in all areas studied; for invasive species, its effects are felt only in the driest areas. Through the annual growth rings of the species, we found that local environmental conditions do not greatly influence the growth of the invasive species, but reduce the growth of the native species with increasing temperatures, highlighting the plasticity of the invasive taxon.