Designate protected area

Overall effectiveness category Likely to be beneficial
Number of studies: 4
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How is the evidence assessed?

Effectiveness

50%
Certainty

40%
Harms

10%

Calculating overall effectiveness category

Background information and definitions

This action includes protection of specific marshes or swamps, or areas that contain these habitats, whether through legal means (e.g. many National Parks and Marine Protected Areas) or some other agreement or commitment (e.g. Biosphere Reserves, Ramsar Sites, Wild and Scenic Rivers). Protected areas may be publicly or privately owned.

Protected areas may prohibit all human uses, or allow sustainable use to varying degrees and perhaps within designated zones. ‘Wise use’ of wetlands – allowing activities such as collection of plant materials for handicrafts, fishing, hunting, charcoal production and scientific research, as long as the ecological character of the site is maintained – is a fundamental principle of the Ramsar Convention (Ramsar Convention Secretariat 2010).

Studies that include, or aim to conserve, at least some marsh or swamp habitat are summarized as evidence for this action. Given the broad scale of this action, results may include other wetland habitats (e.g. peatlands and mudflats), aquatic habitats (e.g. rivers and lakes) or upland habitats (e.g. forests). It is not unusual for an entire catchment or watershed to be protected (Sullivan et al. 2018).

We have not summarized the following types of information, which are particularly weak or misleading when assessing effectiveness of protected areas:

Information about implementation only (i.e. area or number of protected sites).
Studies comparing protected and unprotected areas at a single time point (e.g. Imbert & Delbé 2006; Di Bella et al. 2014). In such studies, differences between protected and unprotected areas may simply reflect the fact that “better” areas (e.g. containing more species or marsh/swamp habitat) were selected for protection (Joppa & Pfaff 2009).
Studies examining the effects of specific interventions designed to tackle threats within protected areas (e.g. hunting, vehicle use, overharvesting). These studies are considered in other chapters.

Caution: Restricting certain activities in protected areas could actually increase the threat they pose. For example, restricting prescribed burning might (a) cause a build-up of vegetation or litter, stockpiling fuel for wild fires, or (b) encourage more illicit and uncontrolled burning due to the hurdle of obtaining permits (Pott & Pott 2004).

^{Di Bella C.E., Jacobo E., Golluscio R.A. & Rodríguez A.M. (2014) Effect of cattle grazing on soil salinity and vegetation composition along an elevation gradient in a temperate coastal salt marsh of Samborombón Bay (Argentina). Wetlands Ecology and Management, 22, 1–13.}

^{Imbert D. & Delbé L. (2006) Ecology of fire-influenced Cladium jamaicense marshes in Guadeloupe, Lesser Antilles. Wetlands, 26, 289–297.}

^{Joppa L.N. & Pfaff A. (2009) High and far: biases in the location of protected areas. PLoS ONE, 4, e8273.}

^{Pott A. & Pott V.J. (2004) Features and conservation of the Brazilian Pantanal wetland. Wetlands Ecology and Management, 12, 547–552.}

^{Ramsar Convention Secretariat (2010) Wise Use of Wetlands: Concepts and Approaches for the Wise Use of Wetlands, Fourth Edition. Ramsar Convention Secretariat, Gland.}

^{Sullivan C.A., Finlayson C.M., Heagney E., Pelletier M.-C., Acreman M.C. & Hughes J.M.R. (2018) Wetland landscapes and catchment management. Pages 404–421 in: J.M.R. Hughes (ed.) Freshwater Ecology and Conservation: Approaches and Techniques. Oxford University Press, Oxford.}

Study locations

Key messages

Four studies evaluated the overall effects, on vegetation or human behaviour, of designating protected areas involving marshes or swamps. There were two studies in China, one in Malaysia and one in Puerto Rico.

VEGETATION COMMUNITY

Overall extent (4 studies): Two studies (one replicated, one before-and-after) in China reported that the area of marsh, swamp or unspecified wetland in protected areas declined over 6–12 years. One replicated, site comparison study in Puerto Rico reported that protection had no clear effect on mangrove forest area, with similar changes over 25 years in protected and unprotected sites. One study of a mangrove forest in Malaysia reported that it retained at least 97% of its forest area over 98 years of protection as a forest reserve.

VEGETATION ABUNDANCE

VEGETATION STRUCTURE

Overall structure (2 studies): One replicated study in Chinareported “degradation” of the landscape structure of protected wetlands over 12 years. One before-and-after study in China reported fragmentation of wetland habitat within a protected area, but that this meant its structure became more like it had been 10–40 years previously.

About key messages

Key messages provide a descriptive index to studies we have found that test this intervention.

Studies are not directly comparable or of equal value. When making decisions based on this evidence, you should consider factors such as study size, study design, reported metrics and relevance of the study to your situation, rather than simply counting the number of studies that support a particular interpretation.

Supporting evidence from individual studies

A study in 1908–2006 of a sustainably managed mangrove forest in Peninsular Malaysia (Chong 2006) reported that it retained at least 97% of its mangrove coverage over this period. Mangrove coverage may even have increased slightly, through colonization of newly deposited sediments. For context, the study reports 16% loss of mangrove forest coverage across Malaysia between 1973 and 2000, but an increase of around 6% in Perak State (where the studied managed forest is located) between 1980 and 2000. Methods: The Matang Mangrove Forest Reserve has been protected and managed with sustainable, rotational wood harvesting since 1908. The study does not report details of the methods used to monitor mangrove coverage. Most data are taken from previously published sources.
Study and other actions tested
Referenced paper
Chong V.C. (2006) Sustainable utilization and management of mangrove ecosystems of Malaysia. Aquatic Ecosystem Health & Management , 9, 249-260.
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.
Study and other actions tested
Referenced paper
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.
A replicated study in 2000–2012 of 28 protected areas in northeast China (Lu et al. 2016) reported that the area of marsh and swamp within them decreased over time. Statistical significance was not assessed. The combined area of marshes and swamps decreased by 9% between 2000 and 2012, from 8,444 km² to 7,724 km². The area of natural aquatic habitats (rivers and lakes) decreased by 16%, from 5,805 km² to 4,886 km². The biggest cause of these losses was conversion to cropland (responsible for 39% of the area of marsh/swamp/aquatic habitat lost). The study also reported “degradation” of the landscape-scale structure of marsh/swamp/aquatic habitats in 21 of the 28 protected areas (reported as an index based on metrics such as the size, shape and separation of habitat patches). Methods: Twenty-eight protected areas were studied. They had been established between 1979 and 2003 (22 before 2000). All but one contained areas of marsh and/or swamp. Most were probably freshwater but some were probably brackish/saline (not explicitly reported). Land cover was determined from satellite images taken in summer or autumn 2000 and 2012. Classifications were verified in the field. Rainfall was similar in both years for each protected area (statistical significance not assessed).
Study and other actions tested
Referenced paper
Lu C., Wang Z., Li L., Wu P., Mao D., Jia M. & Dong Z. (2016) Assessing the conservation effectiveness of wetland protected areas in northeast China. Wetlands Ecology and Management, 24, 381-398.
A before-and-after study in 1972–2013 of a protected area in northwest China (Yu et al. 2017) reported that the area of wetland habitat declined despite protection, and that the habitat became more fragmented. Statistical significance was not assessed. The study site was protected as a National Nature Reserve in 2007. Between 2007 and 2013, wetland area declined from 657 km² to 588 km². For comparison, wetland covered 755 km² in 1972 and 798 km² in 1998. Between 2007 and 2013, the wetland habitat also became more fragmented, comprised of more, smaller patches with more complex borders (data reported as landscape metrics). This was a return towards the habitat configuration recorded in 1972 and 1998. The study also noted increasing rainfall, temperature, human population and farmland area near the study site. Methods: Land cover on the site of Ebinur Lake Wetland National Nature Reserve was mapped in two years before protection (1972, 1998) and two years after protection (2007, 2013). The date of protection was verified for this summary using Zhang et al. (2019). Data sources included satellite images, photos and GPS data. Wetland habitat excluded water bodies.
Additional Reference: Zhang F., Yushanjiang A. & Jing Y. (2019) Assessing and predicting changes of the ecosystem service values based on land use/cover change in Ebinur Lake Wetland National Nature Reserve, Xinjiang, China. Science of the Total Environment, 656, 1133–1144.
Study and other actions tested
Referenced paper
Yu H., Zhang F., Kung H., Johnson V.C., Bane C.S., Wang J., Ren Y. & Zhang Y. (2017) Analysis of land cover and landscape change patterns in Ebinur Lake Wetland National Nature Reserve, China from 1972 to 2013. Wetlands Ecology and Management, 25, 619-637.

Please cite as:

Taylor N.G., Grillas P., Smith R.K. & Sutherland W.J. (2021) Marsh and Swamp Conservation: Global Evidence for the Effects of Interventions to Conserve Marsh and Swamp Vegetation. Conservation Evidence Series Synopses. University of Cambridge, Cambridge, UK.

Where has this evidence come from?

List of journals searched by synopsis

All the journals searched for all synopses

This Action forms part of the Action Synopsis:

Marsh and Swamp Conservation

Related Actions

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Increase ‘on-the-ground’ protection (e.g. rangers) for marshes or swamps Action Link	No evidence found (no assessment)	0	Synopsis Link
Require mitigation of impacts to marshes or swamps Action Link	Likely to be beneficial	9	Synopsis Link
Designate protected area Action Link	Likely to be beneficial	4	Synopsis Link