Can dryland use modify the assemblage of animals removing Prosopis flexuosa (Fabaceae) seeds?

CAMPOS, C. M.; MIGUEL, M. F.; CONA, M. I.

Drakensberg

Simposio; 6th International Symposium-Workshop on Frugivores and Seed Dispersal; 2015

University KwaZulu-Natal

The fruits of Prosopis flexuosa are indehiscent pods, with a mesocarp rich in sugars and protein and palatable to dispersing animals. The aim of this study is to analyse the role of seed removers at sites with different land uses (protected area with grazing exclusion -Ñacuñán Reserve-, protected area with domestic animals included -Ischigualasto Park-, and unprotected area under continuous grazing pressure -adjacent to Ñacuñán Reserve-). Fruit removal field trials are conducted using camera traps (Moultrie M-990i). At each site, we offer 20 pods (250 seeds) under 20 trees for 48h. The main results allow identifying and quantifying seed removal by animals that disperse seeds by endozoochory (native species: Lycalopex griseus, Dolichotis patagonum, Rhea americana, Lama guanicoe; exotic species: Lepus europaeus, cow, horse, donkey) and scatter-hoarding (Microcavia asutralis), and animals that predate seeds (Graomys griseoflavus). In the protected area without livestock and in the unprotected area, the main species removing seeds are G. griseoflavus (41.75±1.4; mean ± SE), L. griseus (13.12±0.9), and M. australis (11.4± 00.9). In the protected area with domestic animals, endozoochorous mammals are the most important dispersers: donkey, L. griseus, cow, horse, and D. patagonum. This is the first study assessing the extent of P. flexuosa seed removal by different animals in drylands under different land use conditions. In the long term, grazing exclusion produces changes in habitat structure and a decrease in the abundance of some dispersers, such as D. patagonum and M. australis, promoting seed removal by sigmodontine rodents that mainly act as seed predators.