Termite assemblages (Blattodea: Isoptera) in a habitat humidity gradient in the semiarid region of northeastern Brazil

ABSTRACT We compared the termite assemblages of different ecosystems in a humidity gradient. Three areas were sampled: (i) a humid montane forest; (ii) a hillside forest where shaded coffee (Coffea arabica Linnaeus, 1753) is cultivated; (iii) a seasonally dry forest (Caatinga). Active collection protocols were employed in each area during the dry and rainy seasons. The species were grouped according to their habitats and feeding habits. A total of 45 termite species belonging to 20 genera and three families were encountered. The termite fauna of the Caatinga was as rich and abundant as that of the humid forest areas, but it was distinct from it in species composition. Most termite species encountered in the montane forest were also found in the agro-ecological site, but some species were only found in the latter. The termite fauna of the Caatinga varied seasonally the most, with significantly reduced abundance during the dry period. When species richness, abundance, and species composition were considered together the climatic seasons were not found to significantly affect the termite faunas in any of the study areas. The numbers of encounters per feeding group and per habitat exploited did not differ among the different areas, or during the different seasons. Even in adjacent areas, the humidity gradient, as well as the vegetational characteristics, are reflected in differences in the termite fauna. Agro-ecological regimes can be considered viable alternatives to traditional methods of cultivation as they largely conserve the biodiversity found in non-modified environments.

摘要 本研究针对湿度梯度下的不同生态系统中的白蚁类群展开对比调查。共设置3个采样区域：(i) 湿润山地森林；(ii) 种植遮阴小粒咖啡（Coffea arabica Linnaeus, 1753）的山坡林；(iii) 季节性干旱森林（Caatinga）。研究于旱季与雨季在各区域均采用主动采集方案，并依据白蚁的栖息环境与取食习性对其进行类群划分。本次调查共记录到隶属于3科20属的45种白蚁。卡廷加群落的白蚁区系物种丰富度与个体丰度均与湿润森林区域相当，但物种组成存在显著差异。山地森林中记录的绝大多数白蚁物种同时存在于该农业生态样地，但亦有部分物种仅见于该样地。卡廷加群落的白蚁区系季节波动最为显著，旱季时个体丰度显著下降。当综合考量物种丰富度、个体丰度与物种组成时，未发现气候季节对各研究区域的白蚁区系存在显著影响。各取食类群与利用生境的记录频次在不同采样区域间以及不同季节间均无显著差异。即便在相邻区域，湿度梯度与植被特征的差异也会体现在白蚁区系的组成差异上。农业生态种植模式可视为传统耕作方式的可行替代方案，因其能够最大程度保留原生未改造环境中的生物多样性。