Non-native plantation monocultures, like early successional forest, could provide services such as carbon sequestration to meet international targets. However, one of the primary venues for developing plantations is tropical dry forest, which is already threatened by severe fragmentation. These forests and dependent wildlife populations could be better protected if the landscape context is considered prior to plantation development. In this analysis, we ask whether teak (Tecona grandis) plantations in Nicaragua could act as a barrier to animal migration and gene flow. We used least-cost path and circuit-based connectivity measures to predict the effect of plantation configuration on forest-dependent species, targeting the endangered Central American spider monkey (Ateles geoffroyi). Circuit-theoretic methods measure flow across multiple potential pathways, providing an additional measure of redundancy compared to a least-cost path. To deduce the effect of plantation configuration, we compared landscape connectivity prior to plantation development to a series of post-development scenarios.
Results/Conclusions
Our results strongly suggest that connectivity will be lost between critical forest stands following the current plantation operations. The effective distance or resistance between specific populations increased as plantation areas were converted to a non-forest matrix (least cost path 31% increase, circuit resistance 81% increase). In addition, new plantations will be developed in 2011 within the single largest continuous forest stand and will potentially bisect animal populations, increasing travel resistance within the stand by a factor of 10 (circuit resistance distance: 4.4 to 47 ohms).This scenario could have been avoided if the landscape had been evaluated prior to plantation development, even using available land cover information. We conclude that non-native reforestation for carbon sequestration can be better balanced with native biodiversity conservation if landscape context is incorporated into planning and certification.
