Controlling a Blackberry Invader

Supporting PhD students is a key part of GCT's work to further our scientific knowledge and understanding of the Galapagos ecosystem. Jorge Luis Renteria is an Ecuadorian researcher working with the Charles Darwin Foundation's Introduced Plants Program and Imperial College in London to assess the impacts of the highly invasive blackberry Rubus niveus.


Jorge Renteria in the field
Rubus niveus, known locally as 'mora', originates from the Himalayas and was introduced to Galapagos in the 1970s for agricultural purposes.  Little did they know that this tenacious plant would actually render massive areas of farmland useless and also impact on native flora - in particular the Scalesia forests of the humid highlands.  The seeds are spread by rats and native birds that feed on the fruit and have now been spread to most of the Islands.  The main reason for the colonising success of this species is the dense 'seed banks' that accumulate - densities of up to 7,000 seeds per m2 have been recorded in one area.  Seeds can stay dormant for 10 years, waiting for the ideal conditions to germinate.  This allows the mora to out-compete many native plants resulting in dense thickets of this prickly shrub.

There is a severe need to improve upon current management strategies - eradication methods in the Galapagos National Park have proved largely unsuccessful and prohibitively expensive. Jorge's project will provide a key baseline to develop further strategies and models for management.

Key aims:

  • To improve understanding of the environmental impacts of R. niveus
  • To assess current management strategies in place e.g. the effectiveness of the eradication programme in Santiago Island
  • To better understand the invasion process
  • To produce a population model to predict results of proposed management strategies

Preliminary results:

  • The growth performance of R. niveus is superior to native species and dramatically alters forest structure
  • Seed density is 4.4x greater than all other native plants
  • In Santiago, herbicide control has been effective in limiting the spread of known populations but difficulties arise in locating other populations before fruiting and halting seed dispersal

Jorge is due to finish his PhD in 2011.  He then hopes to return to Galapagos to further his research.