Unexpected high diversity of galling insects in the Amazonian upper canopy: The savanna out there

A relatively large number of studies reassert the strong relationship between galling insect diversity and extreme hydric and thermal status in some habitats, and an overall pattern of a greater number of galling species in the understory of scleromorphic vegetation. We compared galling insect diversity in the forest canopy and its relationship with tree richness among upland terra firme, várzea, and igapó floodplains in Amazonia, Brazil. The soils of these forest types have highly different hydric and nutritional status. Overall, we examined the upper layer of 1,091 tree crowns. Galling species richness and abundance were higher in terra firme forests compared to várzea and igapó forests. GLM-ANCOVA models revealed that the number of tree species sampled in each forest type was determinant in the gall-forming insect diversity. The ratio between galling insect richness and number of tree species sampled (GIR/TSS ratio) was higher in the terra firme forest and in seasonally flooded igapó, while the várzea presented the lowest GIR/TSS ratio. In this study, we recorded unprecedented values of galling species diversity and abundance per sampling point. The GIR/TSS ratio from várzea was approximately 2.5 times higher than the highest value of this ratio ever reported in the literature. Based on this fact, we ascertained that várzea and igapó floodplain forests (with lower GIA and GIR), together with the speciose terra firme galling community emerge as the gall diversity apex landscape among all biogeographic regions already investigated. Contrary to expectation, our results also support the "harsh environment hypothesis", and unveil the Amazonian upper canopy as similar to vegetation habitats, hygrothermically stressed environments with temperature at lethal limits and high levels of leaf sclerophylly. © 2014 Julião et al

Rehabilitation of Degraded Lands in Semiarid and Subhumid Ecologies in India

Land degradation is a complex phenomenon caused by natural and anthropogenic factors. These factors create and accelerate soil erosion and contribute to the loss of biodiversity and degradation of soil quality and hydrological features. Adoption of a gamut of appropriate soil and water conservation measures, protection of vegetation from overgrazing, assisted regeneration of vegetation, etc. maybe one of the viable options to protect, rehabilitate, and rejuvenate the degraded lands. This paper presents the results achieved 10 years after the application of these measures in the semiarid (Rajasthan) and subhumid (Odisha) ecologies in India. There were considerable changes and improvements in ecological features in both the ecologies. Reduced level of soil erosion, some increase in soil depth, enhanced vegetation cover, improved vegetation composition and intraspecies density, and hydrological conditions were positively altered. The hydrological changes were visible not only at the study site but also in the villages inhabited in downstream of the study sites, where inhabiting communities claim increased and for longer duration water level in their wells. Due to increased water availability, these communities have successfully ventured in growing more crops, indicating increased cropping intensity on their land. The changes have also been noticed on the improvement in the composition of floating avian and wild animal population at the rehabilitated sites, which have attracted their in-migration, and appear capable of harboring them. The impact of rehabilitation efforts on soil chemical properties in both ecologies has been negligible during a decade or more of the rehabilitation efforts in this study. Therefore, any significant improvement in soil quality improvement in short term seems an unrealistic and fallacious expectation. The rehabilitation of degraded lands through social and biological measures, e.g., respectively, protection from grazing and assisted regeneration of vegetation, seems to have better impact than the physical/mechanical means. The details of the findings from the two cases – one from each ecology – are presented in this paper