Shrub swamps — also calledscrub swamps orbuttonbush swamps — are a type offreshwaterwetlandecosystem occurring in areas too wet to becomeswamps ("true" orfreshwater swamp forest), but too dry or too shallow to becomemarshes.[1][2] They are often considered transitional ("mid-successional") betweenwet meadows orfens and conifer or hardwood swamps.
By some classifications,[which?] shrub swamps must have at least 50% shrub cover and less than 20% tree cover. Other definitions[which?] specify large shrubs with small trees less than 35 feet (11 m) in height. Creation of shrub swamps often follows a catastrophic event in a forested swamp (flood, cutting, fire, or windstorm). Another route of development is via drained meadows and fens which progress to shrub swamps as a transitional state to forested swamps.
As a wet meadow matures it begins to fill in with vegetation and as this decomposes the soil thickens creating high spots (hummocks) above the water. Shrubs and small trees begin to grow on these. Shrub swamp water comes from run-off, streams and rivers and the water moves in and out of the swamp throughout the year. Consequently, they tend to be drier than wet meadows or forested swamps and permit water intolerant plant species to grow on the hummocks. Shrub swamps typically occur on organic soils, such asmuck and shallowpeat soils. Common plants found in the shrub swamps ofNorth America includealders,willows,elderberry andhighbush blueberry.
 |
