Plant morphometry matches beetle diversity: effects of natural adjacent vegetation on grain Amaranth crop under small-holder conditions

Grain Amaranth, Amaranthus hypochondriacus L., is an emerging arable crop cultivated worldwide. One way to obtain resources from the crop, other than grain, is to grow Amaranths in the dry season and harvest only the leaves. In this environmental condition the response of an Amaranth agroecosystem to the presence of natural and semi-natural habitats or other crops has not been studied yet. We analysed the response of (1) Amaranth morphometry and (2) alpha and beta diversity of beetles to the nearness of adjacent vegetation and natural habitats (such as deciduous forest) at the small-holder conditions. Our results showed that A. hypochondriacus crop plants responded positively to the presence of an ecotone (adjacent vegetation) and the natural habitat (deciduous forest), i.e., A. hypochondriacus plants grew bigger in the section nearest to adjacent vegetation, which was a pattern consistent in time. Moreover, for beetles (considered as a bioindicator group), richness was different amongst the study areas and negatively followed the gradient of perturbation. These results suggest that Amaranth crop is sensitive to the presence of natural and semi-natural habitats but not to other crops in the dry season. In addition, beetles match the response of Amaranth plants. This is the first time that this type of data is recorded in grain Amaranth agroecosystem and it will help to understand the interaction amongst grain Amaranth agroecosystems, biodiversity, and natural adjacent vegetation to boost ecosystem services.