Ecology of small streams on the west coast of the South Island, New Zealand

Winterbourn, Michael J.; Collier, Kevin J.; Graesser, A.

doi:10.1080/03680770.1987.11898035

Cited by 8 publications

(10 citation statements)

References 7 publications

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“…In New Zealand, algal production in brown-water and clear-water streams with pH <5 can be severely nitrogen limited (Winterbourn, Collier & Graesser, 1988;M.J. Winterbourn, unpublished data), and where entire stream systems draining hard rock catchments have low pH, nutrient limitation of the kind described by Maurice et a!.…”

Section: Introductionmentioning

confidence: 97%

Nutrients, algae and grazers in some British streams of contrasting pH

1992

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1. The relationship between algal biomass accumulation, invertebrate colonization, and stream-water pH was investigated in seven streams in three regions of England and Wales. Possible nutrient limitation of algal production at all sites was examined with diffusion substrata. 2. Periphyton assemblages on experimental substrata after 30 days were dominated by diatoms, notably Eunotia spp., at all sites. Algal pigment concentration (chlorophyll a and phaeopigments) was not correlated with stream-water pH, and mean concentrations on control (unenriched) substrata ranged from 0.08 to 1.94|xgcm~^. 3. The growth response of periphyton to nutrient additions was site specific. Algal production was stimulated by nutrient additions at sites in the English Lake District and Llyn Bhanne (south-west Wales), but not in the Ashdown Forest (southern England). 4. Larval Chironomidae were the main invertebrates retrieved from substrata at all sites. Within all three regions, larval abundance was positively related to algal pigment concentration (biomass). Abundance of the stonefly Nemurella pictetii was also positively correlated with algal biomass at the one site where it occurred. 5. Our results indicate that epilithic algal production in small, oligotrophic streams is unlikely to be determined primarily by pH. Neither do they support the view that an absence of grazers from add streams is necessarily due to an inadequate food supply.

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Section: Introductionmentioning

confidence: 97%

Nutrients, algae and grazers in some British streams of contrasting pH

1992

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“…Consequently, stream discharges exhibit great temporal variability and streambeds are unstable. Above the tree-line, allochthonous inputs in the form of windblown leaves and other riparian vegetation are low, and retention of this material is often poor, as reported for sub-alpine streams in Westland (e.g., Winterbourn et al 1988). Bryophytes enhance habitat stability in these streams which may partially explain the high densities of invertebrates within this habitat (Suren 1990, in press).…”

Section: Bryophytesmentioning

confidence: 99%

Consumption of aquatic bryophytes by alpine stream invertebrates in New Zealand

Suren

Winterbourn

1991

New Zealand Journal of Marine and Freshwater Research

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represented a less nutritious food source for animals. Avoidance of bryophyte tissues thus reflects a combination of the presence of alternative foods and their low nutritional value; bryophytes may also contain antifcedant compounds.Keywords aquatic bryophytes; invertebrates; feeding; bryophagy; stable carbon analysis; autochthonous; allochthonous; food value; antiherbivore compounds Abstract Gut contents of 23 invertebrate taxa that dwell among bryophytes in two small New Zealand alpine streams with different riparian vegetation were examined. Bryophyte fragments were found in guts of 14 taxa, but only the tipulid Limonia hudsoni and the oeconesid caddisflies Zelandopsyche ingens and Oeconesus similis commonly consumed bryophytes. Bryophyte-dwelling animals consumed more periphyton at the unshaded site or riparian vegetation at the shaded site than did animals dwelling amongst gravels. Stable carbon isotope ratios were compared between selected animals and plants, and indicated that animals in the unshaded site relied primarily on autochthonous detritus, whereas animals from the shaded site relied on allochthonous detritus.

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“…From general considerations in fluvial systems with permanent flows, the 'River Continuum Concept' has been proposed as an integrating theory [32], but the validity of this concept in temporary rivers has been questioned by many authors [3,16,26,35,36]. From the degree of irregularity of its flow, the Palancar stream cannot be considered a continuous river.…”

Section: Introductionmentioning

confidence: 99%

The dynamics of fish populations in the Palancar stream,a small tributary of the river Guadalquivir, Spain

et al. 2001

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-The relationship between flooding and changes in the size distribution of fish populations in the Palancar stream confirms observations in other rivers. On average, density decreased by 36.2 % and biomass increased by 14.5 %, passing from a period of severe drought to one of heavier than normal rains. Precipitation is the most important of the many factors affecting the populations of the Palancar stream; the most evident changes all occurred after the drought. During the drought period, the marked seasonal fluctuation in flow was the most important factor regulating the population dynamics. Fish density and biomass varied in proportion to the water volume. During the rainy period, the studied section of the river was found to be an important reproduction and nursery area, with juveniles and individuals of reproduction age dominating. The presence of Micropterus salmoides, an introduced piscivorous species, is another factor affecting the population dynamics in the Palancar stream. The observed absence of age 0+ individuals of the dominant populations is considered a direct effect of predation.

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Ecology of small streams on the west coast of the South Island, New Zealand

Cited by 8 publications

References 7 publications

Nutrients, algae and grazers in some British streams of contrasting pH

Nutrients, algae and grazers in some British streams of contrasting pH

Consumption of aquatic bryophytes by alpine stream invertebrates in New Zealand

The dynamics of fish populations in the Palancar stream,a small tributary of the river Guadalquivir, Spain

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