Management of plant invasions mediated by frugivore interactions

Abstract

Summary1. Some of the most damaging invasive plants are dispersed by frugivores and this is an area of emerging importance in weed management. It highlights the need for practical information on how frugivores affect weed population dynamics and spread, how frugivore populations are affected by weeds and what management recommendations are available. 2. Fruit traits influence frugivore choice. Fruit size, the presence of an inedible peel, defensive chemistry, crop size and phenology may all be useful traits for consideration in screening and eradication programmes. By considering the effect of these traits on the probability, quality and quantity of seed dispersal, it may be possible to rank invasive species by their desirability to frugivores. Fruit traits can also be manipulated with biocontrol agents. 3. Functional groups of frugivores can be assembled according to broad species groupings, and further refined according to size, gape size, pre-and post-ingestion processing techniques and movement patterns, to predict dispersal and establishment patterns for plant introductions. 4. Landscape fragmentation can increase frugivore dispersal of invasives, as many invasive plants and dispersers readily use disturbed matrix environments and fragment edges. Dispersal to particular landscape features, such as perches and edges, can be manipulated to function as seed sinks if control measures are concentrated in these areas. 5. Where invasive plants comprise part of the diet of native frugivores, there may be a conservation conflict between control of the invasive and maintaining populations of the native frugivore, especially where other threats such as habitat destruction have reduced populations of native fruit species. 6. Synthesis and applications . Development of functional groups of frugivore-dispersed invasive plants and dispersers will enable us to develop predictions for novel dispersal interactions at both population and community scales. Increasingly sophisticated mechanistic seed dispersal models combined with spatially explicit simulations show much promise for providing weed managers with the information they need to develop strategies for surveying, eradicating and managing plant invasions. Possible conservation conflicts mean that understanding the nature of the invasive plant-frugivore interaction is essential for determining appropriate management.

The role of avian frugivores on germination and potential seed dispersal of the Brazilian Pepper Schinus terebinthifolius

“…10,no. 3 of the frugivores' preferred habitat within fragmented landscapes (Buckley et al 2006). Mandon-Dalger et al (2004) observed a possible synergistic interaction between alien birds and alien weeds, including Schinus in Reunion Island.…”

“…Linnebjerg et al 2009). Information on frugivores and the role of different dispersers should be considered at all stages of weed management (Buckley et al 2006). An opposite perspective rises in areas of natural occurrence of Schinus in South America.…”

“…As a toxic weed which threatens biodiversity, it has been target of eradication and/or control activities by conventional and biological methods in the US mainland (Morton 1978, Cuda et al 2005, as well as Hawaii (Hight et al 2003). The high ecological plasticity of Schinus is a common feature of successful invaders (Cuda et al 2005, Buckley et al 2006, Donnelly et al 2008.…”

“…Some of the most damaging invasive plants are dispersed by frugivores (Meisenburg & Fox 2002, Buckley et al 2006 and Schinus is a typical example. A range of bird species have been recorded feeding on Schinus fruits in their natural-occurring or human-disturbed areas in Brazil (e.g., Hasui & Höfling 1998, Krügel & Behr 1998, Jesus & Monteiro-Filho 2007, and countries where it was introduced, such as Australia (Panetta & McKee 1997), United States (Mytinger & Williamson 1987), Reunion Island in the Indian Ocean (Tassin et al 2007), Hawaiian Islands in the Pacific Ocean, and Bahamas in the Atlantic Ocean (Morton 1978).…”

Seed dispersal networks in the Galápagos and the consequences of alien plant invasions

“…There are increasing efforts to collect information on the potential dispersers of invasive plant species [12] and on the plants dispersed by introduced animals [13]. However, rigorous information on the entire species assemblages of plants, seed dispersers and their interactions is still rarely available [14]. Even when such studies exist, they have mainly considered birds, with reptiles and mammals receiving much less attention [15].…”