Ed. Edwards et Ad. Huryn, EFFECT OF RIPARIAN LAND-USE ON CONTRIBUTIONS OF TERRESTRIAL INVERTEBRATES TO STREAMS, Hydrobiologia, 337(1-3), 1996, pp. 151-159
Since terrestrial invertebrates are often consumed by stream fishes, l
and-use practices that influence the input of terrestrial invertebrate
s to streams are predicted to have consequences for fish production. W
e studied the effect of riparian land-use regime on terrestrial invert
ebrate inputs by estimating the biomass, abundance and taxonomic richn
ess of terrestrial invertebrate drift from 15 streams draining catchme
nts with three different riparian land-use regimes and vegetation type
s: intensive grazing - exotic pasture grasses (4 streams), extensive g
razing - native tussock grasses (6 streams), reserve - native forest (
5 streams). Terrestrial invertebrate drift was sampled from replicated
stream reaches enclosed by two 1 mm mesh drift nets that spanned the
entire channel. The mean biomass of terrestrial invertebrates that ent
ered tussock grassland (12 mg ash-free dry mass m(-2) d(-1)) and fores
t streams (6 mg AFDM m(-2) d(-1)) was not significantly different (p >
0.05). However, biomass estimated for tussock grassland and forest st
reams was significantly higher than biomass that entered pasture strea
ms (1 mg AFDM m(-2) d(-1)). Mean abundance and richness of drifting te
rrestrial invertebrates was not significantly different among land-use
types. Winged insects contributed more biomass than wingless inverteb
rates to both pasture and tussock grassland streams. Winged and wingle
ss invertebrates contributed equally to biomass entering forest stream
s. Land use was a useful variable explaining landscape-level patterns
of terrestrial invertebrate input for New Zealand streams. Evidence fr
om this study suggests that riparian land-use regime will have importa
nt influences on the availability of terrestrial invertebrates to stre
am fishes.