![Sample our Global Development journals, sign in here to start your access, latest two full volumes FREE to you for 14 days]({"type":"image" , "src" : "/sda/5929/TOC-Subject-Sample-2021-Global-Development.jpg"})
Abstract
Although vast literature exists on the drivers of tropical deforestation and its ecological consequences, less is known about how patterns of forest fragmentation emerge in the first place. The purpose of this paper is to address this issue for the Brazilian portion of the Amazon basin by analyzing the social processes generative of five specific patterns, including rectangular, fishbone, radial, dendritic, and what we refer to as ‘the stem of the rose.’ We argue that forest fragmentation patterns in the Brazilian Amazon are largely determined by the types and arrival times of the agents who engage in land clearing. We also argue that the patterns manifest in the landscape by virtue of road construction and agricultural property formation, which often occur in tandem. We conclude by placing our discussion within legal and institutional contexts, and observe that fragmentation stemming from formal colonization projects is more consistent with biodiversity conservation than that associated with a laissez-faire occupation. However, erosive impacts may be greater in topographically sensitive areas.
Acknowledgments
We would like to thank two anonymous referees and the Editor who provided excellent comments on earlier versions of the manuscript. We remain responsible for any outstanding errors. We are indebted to all individuals who patiently answered our questions and inquiries and shared their knowledge about roads, local histories, and developmental processes all over the Amazon.
Disclosure statement
No potential conflict of interest was reported by the authors.
Notes
1. This digital dataset possesses at least two limitations that constrain our ability to do any temporal analysis: we do not know when road segments were built prior to our baseline year 2003, only after, and some roads may be ephemeral (e.g., certain logging roads and trails) and may have been abandoned after detection. We did not concurrently detect deforestation either and cannot make basin-wide claims about the road-fragmentation pattern nexus, although such work has been conducted for certain regions (e.g., Arima et al., Citation2005, Citation2013; Perz et al., Citation2008; Walker et al., Citation2013).
2. Network length measured within a GIS and included the following states: Acre, Amapá, Amazonas, Mato Grosso, Pará, Rondônia, and Roraima. Tocantins and Maranhão were not included because the predominant vegetation in these latter states is not evergreen forest.
3. We use the term colonization road here, even though they fit our classification as unofficial. Along BR-230, the federal government sometimes built an initial spur to 10 km, but most of the time private agents initiated construction. In all cases studied by the authors on BR-230, private citizens expanded the roads to their current length.
4. Although restricting our assessment to federal investment facilitates our presentation, it fails to capture social dynamics that have at times impacted the building of state roads, which can also distribute fragmentation patterns across the landscape (Schmink & Wood, Citation1984).
5. Another road, Perimetral Norte (BR-210) linking Boa Vista to Macapá along Brazil’s northern borders, was planned but only a few segments were actually built.
6. Projetos de Assentamento (PA) formed pursuant to Direct Action Land Reform (Simmons et al., Citation2010) often display the same spiny organization of space, but on a much smaller scale than the PICs strung out along the federal highways.
7. Schmink and Wood (Citation1984) described how first colonists and ranchers sometimes burned down hardwood trees because the logging industry was incipient in the early stages of frontier expansion in Amazonia, an indication that the agricultural frontier was ahead of the logging frontier at the time.
8. Other meso-scale organizations, such as land companies and social movement organizations (SMOs), also played a role in the process. To facilitate our presentation, we have focused on the upper-tier agency of the ‘state,’ and on the ground-level behaviors of resource-using agents.
9. Caviglia-Harris and Harris (Citation2011) find variations in the relationship between deforestation and settlement patterns in Rondônia, with landscapes on the order of 101–102 km2. The fragmentation patterns in this article extend over 104–105 km2, excepting the extent of the federal network at 106 km2.