Conversion and recovery of Puerto Rican mangroves: 200 years of change

Published source details Martinuzzi S., Gould W.A., Lugo A.E. & Medina E. (2009) Conversion and recovery of Puerto Rican mangroves: 200 years of change. Forest Ecology and Management, 257, 75-84.
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This study is summarised as evidence for the following.

	Action	Category
	Provide general protection for marshes or swamps Action Link
	Designate protected area Action Link

Provide general protection for marshes or swamps

A before-and-after study in 1959–2002 of mangrove forests in Puerto Rico (Martinuzzi et al. 2009) reported that their area increased following legal protection of all mangroves on the island. Between 1959 and 1971, the area of mangroves in Puerto Rico declined from approximately 7,285 ha to 6,745 ha. The study attributes this to urban expansion. In 1972, legal protection was granted to all mangroves in Puerto Rico. Subsequently, the area of mangroves increased to 7,443 ha in 1977 and 8,323 ha in 2002. The study suggests that active restoration efforts and declining agricultural production contributed to this increase, alongside legal protection. The study also notes that lowland freshwater swamps, which were not granted the same protection as mangroves, were “almost none existent” by the early 2000s. Methods: The study was based on historical estimates of mangrove forest area across Puerto Rico, derived from aerial photos or satellite images. Estimates were corrected to include mangrove forests only, not associated wetland ecosystems.

(Summarised by: Nigel Taylor)
Designate protected area

A replicated, site comparison study in 1977–2002 of 97 mangrove forest sites in Puerto Rico (Martinuzzi et al. 2009) reported that site-level protection had no clear effect on mangrove forest area. Statistical significance was not assessed. Between 1977 and 2002, the total area of mangrove forest increased by 10% in protected sites (from 4,440 to 4,900 ha), 9% in partially protected sites (part protected, part unprotected; from 1,880 to 2,050 ha) and 15% in unprotected sites (from 1,090 to 1,250 ha). Considering individual sites, mangrove area increased in 52% of protected sites, 53% of partially protected sites and 40% of unprotected sites. Mangrove area decreased in 18% of protected sites, 17% of partially protected sites and 25% of unprotected sites. Methods: The study was based on historical estimates of mangrove forest area in 97 discrete sites across Puerto Rico, derived from aerial photos or satellite images. Note that site-level protection of mangroves in Puerto Rico occurs against a background of general legal protection of these habitats since 1972.

(Summarised by: Nigel Taylor)