Conservation Evidence: Evidence Data

Collected Evidence: Collected Evidence: Designate protected area 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 China reported “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. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3384https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3384Mon, 12 Apr 2021 08:40:54 +0100Collected Evidence: Collected Evidence: Provide general protection for marshes or swamps Three studies evaluated the overall effects, on vegetation or human behaviour, of providing general protection for marshes or swamps. There was one study in each of Puerto Rico, China and Canada. VEGETATION COMMUNITY Overall extent (3 studies): Two studies in China and Canada reported that the area of wetlands (including habitats other than marshes or swamps) in their study regions declined over 10–29 years, despite general protection of wetlands. However, in China, the decline was slower than in a previous period without protection. One before-and-after study of mangrove forests in Puerto Rico reported that their area increased following legal protection. VEGETATION ABUNDANCE VEGETATION STRUCTURE Overall structure (1 study): One before-and-after study in China reported degradation in wetland landscape structure over 29 years when wetlands were generally protected. However, the decline was slower than in a previous period when wetlands were not protected. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3385https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3385Mon, 12 Apr 2021 09:30:20 +0100Collected Evidence: Collected Evidence: Require mitigation of impacts to marshes or swamps Nine studies evaluated the overall effects – on vegetation or human behaviour – of requiring mitigation of impacts to marshes or swamps. All nine studies were in the USA. VEGETATION COMMUNITY Overall extent (6 studies): Four studies in the USA reported that requiring mitigation of impacts to wetlands did not prevent loss of wetland area: the total area restored/created was less than the area destroyed. One study in the USA reported that the total area of wetlands restored/created for mitigation was greater than the area destroyed. However, the area restored/created was smaller in most individual projects. Two of the studies reported that fewer individual wetlands were restored/created than destroyed. One before-and-after study in the USA found that wetland area declined after legislation to offset impacts came into force, but at a slower rate than before the legislation applied. Four of the studies reported discrepancies between the area of specific vegetation types restored/created vs destroyed. VEGETATION ABUNDANCE VEGETATION STRUCTURE OTHER Compliance (8 studies): Eight studies, all in the USA, provided information about compliance with required mitigation. Five of the studies reported that the total area of wetlands conserved was less than the area required in permits. Three of the studies reported that most mitigation projects failed to meet targets stipulated in permits. One of the studies reported that only one of seven vegetation targets was met in all mitigation sites. One of the studies reported that 64–74% of assessed mitigation areas met success criteria stipulated in permits. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3386https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3386Mon, 12 Apr 2021 11:47:00 +0100Collected Evidence: Collected Evidence: Pay stakeholders to protect marshes or swamps Two studies evaluated the overall effects, on vegetation or human behaviour, of paying stakeholders to protect marshes or swamps. There was one study in each of the UK and Nigeria. VEGETATION COMMUNITY Overall extent (1 study): One replicated, before-and-after, site comparison study in the UK found that paying landowners to manage farmland ditches under agri-environment rules had no clear or significant effect on the frequency of emergent vegetation. Overall richness/diversity (1 study): One replicated, site comparison study in the UK found that farmland ditches managed under agri-environment rules contained a similar number of plant species to ditches not managed under these rules. VEGETATION ABUNDANCE VEGETATION STRUCTURE OTHER Human behaviour (1 study): One study in Nigeria reported that 58 communities with access to micro-credits for sustainable development changed their behaviour. In particular, they switched from livelihood practices that damaged mangrove forests to more sustainable practices. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3387https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3387Mon, 12 Apr 2021 11:49:07 +0100Collected Evidence: Collected Evidence: Increase ‘on-the-ground’ protection (e.g. rangers) for marshes or swampsWe found no studies that evaluated the effects, on vegetation or human behaviour, of increasing ‘on-the-ground’ protection for marshes or swamps. ‘We found no studies’ means that we have not yet found any studies that have directly evaluated this action during our systematic journal and report searches. Therefore we have been unable to assess whether or not the action is effective or has any harmful impacts. Please get in touch if you know of such a study for this action.Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3388https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3388Mon, 12 Apr 2021 11:51:05 +0100