# Forestry Best Management Practices Relationships with Aquatic and Riparian Fauna: A Review
## 3 Results and Discussion
### Streamside Management Zones  
SMZs, also known as riparian buffers, forest buffers, and filter strips, are a particularly important type of BMP because they provide a zone for water quality protection between managed lands and the stream [97; 98; 99]. For example, SMZs promote sediment and nutrient trapping by slowing and often preventing entry into aquatic systems [53; 100]. Appropriately managed and designed SMZs moderate light infiltration, dampen or minimize aquatic and terrestrial temperature gradients, slow nutrient flow, maintain hypoheic and hydrologic function, and preserve riparian vegetative composition and structure [2; 15; 101; 102; 103; 104; 105; 106]. However, SMZs also provide forest habitat for a variety of species and maintain structures important to faunal communities in the presence of forestry operations [27; 40; 107; 108; 109]. SMZs provide coarse woody debris and detritus inputs that serve as food and habitat structure for aquatic species [109; 110; 111; 112] and critical microhabitat for riparian organisms for nesting, roosting, feeding, or breeding. Implementation requirements and subsequent success of an SMZ depends on the aquatic species of concern, and to what extent managers need to protect riparian and aquatic ecosystems from disturbance [47]. As different species of wildlife have different sensitivities to environmental changes, they also have differing requirements for optimal environments, including canopy composition, width of the riparian buffer, and patch length along the stream [34]. SMZs can be designed to address these habitat requirements. Alterations to aquatic and terrestrial temperature gradients could impact aquatic biota, restricting movement, limiting biological functions, and altering habitat suitability [20; 113; 114; 115]. SMZs provide shade and relatively stable canopy composition and streambank stability; therefore, these riparian buffers help preserve terrestrial and aquatic temperature regimes in riparian areas, safeguarding and maintaining wildlife populations [114; 115; 116; 117; 118; 2; 115]. Canopy cover influences light and temperature regimes, which are important to many vertebrate species but also to other sensitive fauna such as dragonflies (Odonata) and moths and butterflies (Lepidoptera) [116; 119; 120; 121]. Species preferences for light infiltration, solar radiation, and temperature regimes differ [122; 47]. Although some species are sensitive to changes in these parameters, others may benefit from the manipulation and alteration of riparian vegetation [123]. Riparian zones can be managed to favor the life history for a particular species, but specific information for many threatened and endangered species is lacking and some species have conflicting life history needs. Thus, additional research is needed to ascertain how forestry riparian zones can be managed to best address various species' habitat requirements. SMZs also provide a source for coarse woody debris, snags, tree cavities, and rotting logs [39; 112]. These structures create diverse habitat and microtopography, benefiting a variety of riparian species [112; 124] and species within the surrounding landscapes where these structures may be less abundant. The benefits of coarse woody debris in aquatic ecosystems depend on the amount and size of such debris [39; 112; 2]. Because coarse woody debris can increase habitat diversity, it is an essential component of eastern stream ecosystems, and is required by fish populations [39] and some turtles [124]. Woody debris is typically generated during harvesting operations, and riparian buffers can be managed to provide woody debris input into aquatic ecosystems [110; 111; 112; 113; 114; 115; 39]. Although additional nutrient inputs sometimes can enhance fish habitat in headwater streams, in some cases, these inputs could stimulate downstream eutrophication [2].