No abstract

Ants are effective at moving seeds toward their nests, something that may benefit the seeds. We evaluated whether seed movements that may be useful for the rehabilitation of degraded pastures in Colombia can be enhanced by local ants. An artificial aril was prepared and then evaluated in six open cattle pasture farms. Twenty paper disks (each holding seeds with an artificial aril, honey, tuna oil, and control) were set up along linear transects at each farm, and monitored five times in 48 hours. A total of 340 out of 480 seeds were moved from the experimental units by ants. Seeds with tuna oil and an artificial aril were removed twice as frequently as the control and honey smeared seeds. Ectatomma ruidum, Solenopsis geminata, and Pheidole sp. removed the majority of seeds. Advantages of the artificial aril over tuna oil are discussed. This inexpensive technique can enhance seed movement by generalist ants in degraded pastures, likely contributing to regeneration and ecological rehabilitation.

Livestock production models prevailing in Colombian Andes are simplified treeless pastures for extensive ranching, with the consequent reduction of environmental services, such as seed dispersal, due to lack of primary dispersers, scarcity of adequate sites for seedling establishment and competition with grasses. This study evaluated if, in these harsh environments, ants can promote the colonization of arboreal species through directed dispersion of seeds towards the nests. Ten seeds of each species were offered to ants in six grazing pastures. Ants removed 25% of the seeds (1827) in 48 hours. Preference for arillated and small-to-medium sized seeds, such as Pithecellobium dulce, and Guazuma ulmifolia, was observed. Cyphomyrmex major, Ectatomma ruidum, Solenopsis geminata and Atta cephalotes were the key ant species in seed removal. It was concluded that functional ant groups present in the pastures could contribute to secondary dispersion of seeds with potential for restoration.

Land use management influence changes in biodiversity beyond the targeted species. Management practices in coffee plantations have shifted from coffee growing below accompanying (shade) trees, to intensified monocultures in which coffee grows fully exposed to the sun. Anthropogenic disturbance causes changes in species composition relative to adjacent natural patches and reduces their biotic heterogeneity. Here, we assessed the impact of coffee plantation management practices on the taxonomical, phylogenetic and functional composition of ant communities, an ecologically dominant group and crucial biological pest controller in these agroecosystems. We hypothesized that shade‐grown coffee plantations would harbour ant communities similar to those of nearby forest patches, but dissimilar to those of intensified monocultures. We surveyed ant diversity in eight shade‐grown coffee farms, eight intensive coffee monocultures and eight forest patches. We used a combination of active and passive sampling methods over two field campaigns spanning 6 months. Our results support our hypothesis for all diversity dimensions. Additionally, ant communities in intensified monocultures were taxonomically and functionally, but not phylogenetically, more homogeneous than those found in forest patches and shade‐grown plantations. Synthesis and applications. Our findings support the idea that practices in shade‐grown coffee plantations buffer the impoverishment of multiple diversity dimensions after forest conversion. Additionally, we identified that leaf‐litter depth and number of twigs mitigate ant diversity loss which, in turn, can favour the presence of potential biocontrol agents. By assessing and integrating multiple biodiversity dimensions into management strategies, farmers and interested parties can minimize future biodiversity and ecosystem service loss.