The seed dispersal system and natural recruitment of invasive Pyracantha species in South African afromontane grasslands

Supervisors: Dr. Sandy Steenhuisen & Dr. Grant Martin

Donald completed his undergraduate at the University of the Free-State-Bloemfontein campus. He subsequently completed BSc honours majoring in Botany with the UFS in 2017. Donald has worked on vegetation analysis using the Braun-Blanquet method which will be usefull in his Masters degree working on Pyracantha species. Donald started his MSc in the beginning of 2018 and is based at University of the Free State, Department of Plant Sciences, Natural and Agricultural Sciences Phuthaditjhaba campus.

A fruiting bush of Pyracantha angustifolia (Photo: Trevor James)

Project Background

The introduction of non-indigenous species can have strong adverse effects on the native ecosystem. These species, released from natural predators, often reproduce and spread quickly, and out-compete/displace native fauna/flora, ultimately causing declines in native species' population numbers, leading to local extinctions. Non-native plant species encroaching on the habitats of indigenous plant species can lower reproductive success of other plants in a community by disrupting pollination and seed dispersal mechanisms (through competition for example). Many invasive species also owe their successful spread to their ability to self-pollinate and set seed without the need for pollinators. Others use native fauna as substitute pollinators and seed dispersers. It is thus essential to build our knowledge of the reproductive ecology of non-native species to guide in managing their spread.

As predicted by Carbutt (2012), members of the plant genus Pyracantha (commonly known as firethorns, family Rosaceae), brought into South Africa as ornamental plants, have become Category 1b invaders. This means that these species have high invasive potential, require compulsory control as part of an invasive species control programme, and must be removed and destroyed (SANBI 2015). Native fauna often act as substitute pollinators and seed dispersers for alien species and thus knowledge of how native species may be contributing to the spread of these invasives is valuable for any invasive species control programme. In this study we set out to determine the seed dispersal system of invasive Pyracantha species in afromontane areas of the eastern Free State and northern KwaZulu-Natal.

The small yellow/orange/red apple-like fruits of Pyracantha species are typically eaten and dispersed by frugivorous birds. The presence of these fruit-bearing bushes in the afromontane grasslands of eastern South Africa present an unusual situation in that the grassland flora is largely depauperate of brightly coloured fleshy fruit-bearing plant species. Fruiting firethorn bushes can be seen from far distances as bushes are covered in the brightly coloured fruits in an otherwise drab-coloured winter landscape. Preliminary observations suggest bird dispersal but no concrete data exists on which of our local bird species are dispersing the fruits and how effective they are at dispersing them.

Donald investigating Pyracantha angustifolia in the field

Progress to date

July 2018

Field trip 1: On the 11^th of July Dr. Sandy Steenhuisen and Donald adams visited a number of sites around Clarens in the Eastern Free state to set up camera traps. A number of promising sites were identified and four cameras deployed in the field.

Last Modified: Fri, 03 Aug 2018 09:54:39 SAST