Natural processes, corridors, and networks 231organisms, and increases the rich floodplain habitat diversity of wetland
depressions, streambanks, sandy ridges, and surface microheterogeneity.
(F) River-ladder pattern.A‘‘river ladder” to protect rivers has vegetation strips
along both sides of a floodplain to facilitate wildlife movement and pro-
tect hillslopes and adjacent upland, plus a sequence of large vegetation
patches crossing the floodplain that reduce flooding, trap sediment,
contribute wood for downriver fish habitat, provide organic matter for
aquatic food chains, and maintain diverse habitats with rare floodplain
species.
(G) Drainage basin and stream corridor.The hydrologic, physical, chemical, and
biological characteristics of a stream/river can be modified or mitigated
by the riparianorstreamcorridor, but are much more affected and
effectively managed by the types and spatial arrangement of land use
across the watershed or drainage basin.
(H) Aquifer water.Aquifergroundwater, which (except in limestone areas)
moves very slowly and has little capacity to remove pollutants, is mainly
kept clean by a complete cover of natural vegetation, particularly over
its upslope portion.
Natural corridors and the matrix
(A) Corridor functions and their control.Widthandconnectivity are the primary
controls on all five key roles or functions of natural-vegetation strips or
corridors, i.e., conduit, filter (or barrier), source, sink, and habitat.
(B) Small patches attached to corridors.Small patches attached to natural corri-
dors and networks provide ‘‘rest stops” for wildlife movement that, espe-
cially on long routes, typically increase the chance of a species reaching
adestination.
(C) Gap in a corridor. The ability of an animal moving along a natural-
vegetation corridor to cross a gap or break in the corridor especially
improves as gap length relative to the spatial scale of species movement
shortens, and with more suitable conditions in and around the gap.
(D) Stepping stones between large patches.Forspecies movement between two
large natural patches, a row of stepping stones (small patches) or a poor-
quality corridor is normally better than no corridor, but a cluster of
stepping stones with an overall linear alignment provides alternative
routes and is likely to be more effective.
(E) Habitat contrast.Greaterhabitat contrast or difference between a patch
and a corridor or matrix decreases movement of species between the
patch and an adjoining corridor or matrix, and hence across a landscape.
(F) Matrix heterogeneity.Microhabitat heterogeneity increases the total
species pool of the matrix and its role as a source of species, and if