What makes ecosystem restoration expensive? A systematic cost assessment of projects in Brazil

Abstract

Limited funding is a major barrier to implementing ambitious global restoration commitments, so reducing restoration costs is essential to upscale restoration. The lack of rigorous analyses about the major components and drivers of restoration costs limit the development of alternatives to reduce costs and the selection of the most cost-effective methods to achieve restoration goals. We conducted detailed restoration cost assessments for the three most widespread biomes in Brazil (Amazon, Cerrado, and Atlantic Forest) and estimated the restoration costs associated with implementing Brazil's National Plan for Native Vegetation Recovery (12M hectares). Most surveys (60-90%) reported using the costly methods of planting seedlings or sowing seeds throughout the site, regardless of the biome. Natural regeneration and assisted regeneration approaches were an order of magnitude cheaper but were reported in < 15% of projects. The vast majority of tree planting and direct seeding costs were incurred during the implementation phase, and nearly 80% of projects ended maintenance within 30 months. We estimated a price tag of US$0.7-1.2 billion per year until 2030 to implement Brazil's restoration plan depending on the area that recovers through natural regeneration. Our results offer valuable insights for developing strategies to make restoration cheaper and to increase its cost-effectiveness for achieving diverse benefits in Brazilian ecosystems. Our survey also provides a starting point for sound assessments of restoration costs and their drivers in other biomes, which are needed to reduce the financial barriers to scaling up restoration at a global scale.

The cost of restoring carbon stocks in Brazil's Atlantic Forest

“…Water limitation, in particular, may have played a critical role for the differential performance of restoration approaches, since the study region has a seasonal climate with annual water deficits of 20 mm or more depending on geographical features (Alvares, Stape, Sentelhas, Gonçalves, & Sparovek, 2013). In addition, tree plantations were fertilized, weeded, and planted at a regular spacing, which allow an efficient occupation of the deforested area by trees and enhance their growth, resulting in a higher accumulation of biomass per area (Brancalion, Meli, et al, 2019; Ferez et al, 2015). Our observation that tree plantations initially accumulate more carbon than second‐growth forest corroborates previous results obtained in southern Costa Rica (Holl & Zahawi, 2014) and Queensland, Australia (Shoo et al, 2016).…”

“…Intensive silvicultural practices, such as planting trees at regular spacing, fertilizing soil, and controlling weeds and leaf‐cutter ants, can promote rapid accumulation of aboveground biomass in tree stands (Rubilar et al, 2018; Wheeler et al, 2016). However, intensive silviculture is costly, and restoration projects do not provide sufficient revenues to offset high implementation and maintenance costs (Brancalion et al, 2019). In addition, most low‐resilience sites where tree planting is required to support restoration have been historically used for intensive agricultural production and therefore have high land opportunity costs (Laurance, Sayer, & Cassman, 2014) and altered biophysical conditions that reduce the potential for natural forest regrowth (Chazdon, 2014).…”

The erosion of biodiversity and biomass in the Atlantic Forest biodiversity hotspot

“…We assumed an average value of US$750 per hectare for within-fragment restoration, which includes activities to reduce edge effects, control of invasive species, and enrichment plantings 66,67 . We assumed an average of US$1000 per hectare for land opportunity cost (10 years period for cattle-ranching activities) 68 and an average of US$1500 per hectare for the restoration costs on degraded lands (from seedling plantation to assisted natural regeneration), which varies between US$350 and US$3000 per hectare for the Atlantic Forest 64,[68][69][70] . However, we assumed different restoration costs for each biogeographical region (i.e., less disturbed and fragmented landscapes should cost less to be restored - Supplementary Table 6).…”

Controlling invasive plant species in ecological restoration: A global review

“…However, the methods employed to control invasive plants in restoration may not always result in the expected outcomes, as the same or even new invasive plant species may colonize the site while native species recovery can be insufficient (Reid, Morin, Downey, French, & Virtue, 2009). Effective control of invasive plant species in restoration may also require long‐term investments (Norton, 2009) which are rarely available for restoration projects (Brancalion, Meli, et al, 2019), or rely on chemical methods that are of major environmental concern (Wagner, Antunes, Irvine, & Nelson, 2017). Controlling invasive plants in restoration can thus be an expensive, long lasting and uncertain process, which may compromise the implementation of the global restoration agenda.…”