FSD 2010 - Holbrook

5th International Symposium-Workshop on Frugivores and Seed Dispersal (1985-2010)

Kimberly M. Holbrook

Integrative Ecology Group, Estación Biológica de Doñana – CSIC, Av. Américo Vespucio, s/n, 41092 Sevilla, SPAIN.

kholbrook(a)ebd.csic.es

Activities

I am primarily interested in the ecology and conservation of plant-animal interactions. My research focuses on how dispersal limitation and long-distance dispersal affect plant communities as well as questions related to how seed dispersal is influenced by human activities. To understand seed dispersal processes I estimate dispersal using models based both on frugivore foraging and movement behaviour and genetic relatedness between adult and offspring plants.

Abstract

Human impacts on tropical forest dispersal systems: implications for large frugivorous birds and long-distance dispersal

Kimberly M. Holbrook, Bette A. Loiselle, Thomas V. Dietsch, Tony Chaser, Martin Wikelski, Thomas B. Smith

Anthropogenic influences have major and lasting effects on tropical forest ecosystems and processes. Seed dispersal, one of the key processes that drive forest diversity and genetic structure, has been shown to be negatively impacted by human activities. Long-distance dispersal (LDD) is particularly important in population spread, colonization, and gene flow between populations. Large frugivores, such as hornbills and toucans that are more likely to contribute to LLD, are especially vulnerable to hunting and habitat fragmentation. We discuss the implications of alteration of seed dispersal at local and regional scales for these two large frugivores based upon animal movement tracking and genetic insights on effective dispersal in plants. Previous research showed hornbills to move up to 290 km from tagging sites and to regularly move seeds more than 500 m from fruiting trees. Recent work with hornbills (14 individuals tagged with satellite GPS units) in Cameroon confirms long-distance movements of > 100 km. In Ecuador, toucans were shown to regularly disperse seeds up to 450 m with longest recorded movements of 3.7 km. Finally, a study using molecular methods to compare dispersal distances in hunted and non-hunted sites demonstrated a 50% reduction of dispersal distance by toucans at the hunted site. Frugivore movements likely have a profound effect on forest regeneration and structure and should be considered an important aspect of conservation in tropical forests.

Photo : Rainforest fruit diversity in Yasuni, Ecuador. © Kimberly Holbrook.

Recent references

Holbrook, KM and BA Loiselle. (2009) Seed dispersal in a neotropical tree, Virola flexuosa (Myristicaceae): does hunting of large vertebrates limit seed removal? Ecology 90:1449-1455.

Holbrook, KM, TB Smith, and BD Hardesty. (2002) Implications of long-distance movements by frugivorous hornbills in Cameroon. Ecography 25: 745-749.

Holbrook, KM and T B Smith. (2000) Seed dispersal and movement patterns in two species of Ceratogymna hornbills in a West African tropical lowland forest. Oecologia 125:249-257.

Whitney KD, MK Fogiel, AM Lamperti,KM Holbrook, DJ Stauffer, BD Hardesty, VT Parker and TB Smith. (1998) Seed dispersal by Ceratogymna hornbills in the Dja Reserve, Cameroon. Journal of Tropical Ecology 14:351-371.

Former FSD presentation

Holbrook, KM and BA Loiselle. (2007) Using toucan-generated dispersal models to estimate seed dispersal in Amazonia Ecuador. In: Dennis, AJ, Schupp, EW, Green, RJ and Westcott, DA (eds.) Seed Dispersal: Theory and its Application in a Changing World. CAB International, Wallingford, UK, pp 300-321.