Macroinvertebrate Secondary Production Research Articles

Effects of incomplete sampling on macroinvertebrate secondary production estimates in a forested headwater stream

Estimates of secondary production depend on the efficiency of sampling methods in capturing abundances and body lengths of the entire macroinvertebrate community. The efficiency of common sampling methods in fulfilling these criteria is poorly understood. We compared the effects of a Surber sampler (250 µm mesh size) and a Freeze corer in capturing abundance, biomass, and secondary production of macroinvertebrates in a forested headwater stream. We then examined how the use of nets with different mesh sizes could affect estimates of secondary production. Macroinvertebrate abundance was three times lower, and biomass was three times higher with the Surber than with the Freeze corer. Neither method captured the entire length distribution, and incomplete sampling of body lengths and abundance resulted in underestimating total secondary production by 48% (Surber) and 49% (Freeze corer). We estimated that reducing the mesh size from 250 to 100 µm would reduce the underestimation of production from ~ 48 to ~ 12% due to the inclusion of smaller individuals. Our results improve the efficiency of common sampling methods, allowing a reliable quantification of the role of macroinvertebrates in stream ecosystem functioning.

Resource supply and organismal dominance are associated with high secondary production in temperate agricultural streams

Abstract Agricultural land‐use affects the environmental and biological characteristics of stream ecosystems through multiple pathways including nutrient and pesticide contamination, riparian clear‐cutting and hydromorphological degradation. These changes in the abiotic environment can have a direct effect on the productivity of macroinvertebrate communities through environmental filtering and via altered resource conditions encompassing a shift from allochthonous to autochthonous primary production and changes in elemental stoichiometry and food quality. Additionally, macroinvertebrate productivity can be affected indirectly via biological mechanisms, such as changes in species interactions, richness, competition, and predation. We studied the effects of agriculture on structural and functional descriptors of macroinvertebrate communities by assessing environmental characteristics and macroinvertebrate secondary production (MSP), biomass and density in two forested and two agricultural streams and investigated underlying biotic mechanisms. On average, MSP was 1.6–3.6, biomass 2.8–6.2 and density 5–13 times higher in agricultural than in forested streams. This pattern was associated with higher nutrient concentrations, standing crops of riparian herbaceous vegetation, suspended particulate organic carbon, quantity and quality of epilithic biofilms and chlorophyll‐a concentrations in seston and biofilm of the agricultural streams. Species richness and evenness were significantly lower in agricultural than in forested streams. A negative relationship between MSP and species richness and evenness indicated that density compensation and trait dominance were the prevalent mechanisms facilitating higher MSP in agricultural streams. Our findings suggest that the loss of riparian canopy and excess nutrient conditions are the major environmental drivers contributing to homogenization of ecological niches and dominance of highly productive non‐insect generalist species. This study highlights the importance of an ecosystem approach to understanding how complex aggregate stressors affect the regulation of consumer–resource interactions. There is an urgent need to preserve or restore natural riparian vegetation, fostering habitat and resource diversity and limiting nutrient contamination to stream ecosystems. Read the free Plain Language Summary for this article on the Journal blog.

Shifting stream planform state decreases stream productivity yet increases riparian animal production.

In the Colorado Front Range (USA), disturbance history dictates stream planform. Undisturbed, old-growth streams have multiple channels and large amounts of wood and depositional habitat. Disturbed streams (wildfires and logging < 200years ago) are single-channeled with mostly erosional habitat. We tested how these opposing stream states influenced organic matter, benthic macroinvertebrate secondary production, emerging aquatic insect flux, and riparian spider biomass. Organic matter and macroinvertebrate production did not differ among sites per unit area (m-2), but values were 2 ×-21 × higher in undisturbed reaches per unit of stream valley (m-1 valley) because total stream area was higher in undisturbed reaches. Insect emergence was similar among streams at the per unit area and per unit of stream valley. However, rescaling insect emergence to per meter of stream bank showed that the emerging insect biomass reaching the stream bank was lower in undisturbed sites because multi-channel reaches had 3 × more stream bank than single-channel reaches. Riparian spider biomass followed the same pattern as emerging aquatic insects, and we attribute this to bottom-up limitation caused by the multi-channeled undisturbed sites diluting prey quantity (emerging insects) reaching the stream bank (riparian spider habitat). These results show that historic landscape disturbances continue to influence stream and riparian communities in the Colorado Front Range. However, these legacy effects are only weakly influencing habitat-specific function and instead are primarily influencing stream-riparian community productivity by dictating both stream planform (total stream area, total stream bank length) and the proportional distribution of specific habitat types (pools vs riffles).

Stream ecosystem response to chronic deposition of N and acid at the Bear Brook Watershed, Maine

The Bear Brook Watershed in Maine (BBWM) is a long-term, paired watershed experiment that addresses the effects of acid and nitrogen (N) deposition on whole watersheds. To examine stream response at BBWM, we synthesized data on organic matter dynamics, including leaf breakdown rates, organic matter inputs and standing stocks, macroinvertebrate secondary production, and nutrient uptake in treated and reference streams at the BBWM. While N concentrations in stream water and leaves have increased, the input, standing stocks, and breakdown rates of leaves, as well as macroinvertebrate production, were not responsive to acid and N deposition. Both chronic and acute increases of N availability have saturated uptake of nitrate in the streams. Recent experimental increases in phosphorus (P) availability enhanced stream capacity to take up nitrate and altered the character of N saturation. These results show how the interactive effects of multiple factors, including environmental flow regime, acidification, and P availability, may constrain stream response to chronic N deposition.

Investigating the effect of marine-derived nutrients from spawning salmon on macroinvertebrate secondary production in southeast Alaskan streams

It is generally accepted that juvenile salmonid production is linked, via bottom-up pathways, to marine-derived nutrient (MDN) inputs from spawning salmon. Many studies have used standing stock biomass estimates of aquatic macroinvertebrates to infer relationships between MDN and secondary production in streams that receive spawners. However, no study has measured aquatic macroinvertebrate secondary production in relation to MDN. To assess the relationship between MDN and aquatic insect production, we measured secondary production of the 5 dominant mayfly genera (Baetis spp., Drunella spp., Cinygmula spp., Epeorus spp., and Rhithrogena spp.) and chironomids throughout the primary growing season in 2 streams in southeastern Alaska. Both streams had upstream reaches blocked from spawning salmonids by a waterfall barrier and downstream reaches that received large spawning runs of pink and chum salmon. Four of the mayfly genera studied (Drunella spp., Cinygmula spp., Epeorus spp., and Rhithrogena spp.) had significantly greater production in upstream than in spawning reaches. Secondary production of Baetis spp. was similar between upstream and spawning reaches. Chironomid production was significantly greater in spawning than in upstream reaches. However, biomass of each taxon was maximized in the spring and summer before the primary period of MDN input. These patterns indicate that another factor, primarily spawning disturbance, is an important driver of benthic insect secondary production in these streams and might provide the community structure within which MDN subsidies occur. If these patterns are common in streams that receive salmon runs, then secondary production-mediated links between MDN and juvenile salmonid production might be mostly the result of responses of chironomids and other benthic organisms with similar life histories.

Response of secondary production by macroinvertebrates to large wood addition in three Michigan streams

Summary1. We measured responses in macroinvertebrate secondary production after large wood additions to three forested headwater streams in the Upper Peninsula of Michigan. These streams had fine‐grained sediments and low retention capacity due to low amounts of in‐channel wood from a legacy of past logging. We predicted that wood addition would increase macroinvertebrate secondary production by increasing exposed coarse substrate and retention of organic matter.2. Large wood (25 logs) was added haphazardly to a 100‐m reach in each stream, and a 100‐m upstream reach served as control; each reach was sampled monthly, 1 year before and 2 years after wood addition (i.e. BACI design). Macroinvertebrate secondary production was measured 1 year after wood addition in two habitat types: inorganic sediments of the main channel and debris accumulations of leaf litter and small wood.3. Overall macroinvertebrate production did not change significantly because each stream responded differently to wood addition. Production increased by 22% in the main‐channel of one stream, and showed insignificant changes in the other two streams compared to values before wood addition. Changes in main‐channel macroinvertebrate production were related to small changes in substrate composition, which probably affected habitat and periphyton abundance. Macroinvertebrate production was much greater in debris accumulations than in the main‐channel, indicating the potential for increased retention of leaf litter to increase overall macroinvertebrate production, especially in autumn.4. Surrounding land use, substrate composition, temperature and method of log placement are variables that interact to influence the response of stream biota to wood additions. In most studies, wood additions occur in altered catchments, are rarely monitored, and secondary production is not a common metric. Our results suggest that the time required for measurable changes in geomorphology, organic matter retention, or invertebrate production is likely to take years to achieve, so monitoring should span more than 5 years, and ecosystem metrics, such as macroinvertebrate secondary production, should be incorporated into restoration monitoring programs.

Macroinvertebrate secondary production in 3 forested streams of the upper Midwest, USA

AbstractMacroinvertebrate secondary production was estimated for 2 reaches in each of 3 adjacent forested headwater streams. We had 3 objectives: 1) to compare macroinvertebrate secondary production and community structure both within and among streams to examine the spatial extent of variability, 2) to explore important habitat variables related to secondary production, and 3) to compare our secondary production values to values from other headwater streams in deciduous forests. Principal components analysis separated study streams on the basis of small differences in substrate composition, organic-matter standing crops, and instream wood, but geology, riparian tree species composition, and fine benthic organic-matter standing crops were similar among streams. Secondary production varied among streams (range ∼1.2 to 3.3 g ash-free dry mass m−2 y−1) and was low compared to estimates from other streams draining deciduous forest. Macroinvertebrate communities had relatively higher production of scrapers, pr...

The response of macroinvertebrate production to a pollution gradient in a headwater stream

Summary1. This study quantified patterns of macroinvertebrate secondary production and stored benthic organic matter along a gradient of pollution and habitat channelisation over a 3‐km reach of Goosefare Brook, a first‐order stream in southern Maine (U.S.A.).2. Whole‐community invertebrate production decreased from 26.4 g ash‐free dry mass (AFDM) m−2 year−1 at the reference station to 1.1 g AFDM m−2 year−1 at stations with the greatest levels of pollution. Production decreased along the pollution gradient for most taxa, although decreases were partly offset by production increases in tolerant taxa. Biomass turnover rates (P/B) were less affected by the stresses than was production.3. Differences in functional characteristics of the community were evident at stations with channelised habitat, but overall production declined in a linear pattern that mirrored the pollution gradient. Stored organic matter showed a decline along the gradient, but was also lower at channelised stations. Populations of taxa with documented pollution tolerance were more likely to maintain or increase production and P/B.4. Decreasing biomass because of decreasing stored organic matter and lethal effects of pollutants resulted in shifts in the pathways of energy flow observed at stations exposed to moderate physical or chemical stress, to the loss of most taxa and an extreme (96%) decrease in production at the stations receiving the highest levels of metal pollution.5. The shifting prominence of different taxa along a continuum of stress in Goosefare Brook shows that describing the nature of an impairment in a functional context requires consideration of chemical stressors, habitat alterations and food resources.

Invertebrate food webs along a stream resource gradient

1. The flow of energy through food webs with similar species can vary with both space and time. The river continuum concept (RCC) provides a useful framework for predicting variability in the biota and food availability along streams. We estimated the flow of organic matter (g m−2 year−1) through food webs, arrayed along a stream, that had different resource inputs. Four sites were sampled along the Little Tennessee River, North Carolina, U.S.A.: two fifth order sites, one sixth and one seventh order site. The dominant resource is leaf detritus in the upstream reach (the upstream fifth order site), algae in the mid‐reaches (the downstream fifth and sixth order sites), and suspended material downstream (seventh order site).2. Eleven genera, contributing from 50 to 66% of the total macroinvertebrate secondary production of each site, were studied. We estimated organic matter flow from resource to consumer by combining previously measured rates of invertebrate secondary production with gut content analyses and assimilation efficiencies.3. Organic matter flow through food webs increased in a downstream direction, while the structure of the food webs remained constant. The total food consumed by the taxa analysed increased from 34 g m−2 year−1 at the upstream site to 730 g m−2 year−1 at the most downstream site. We estimate that the organic matter consumed by the entire macroinvertebrate community ranged from 66 to 1164 g m−2 year−1. These results indicate that there is variation in the magnitude of organic matter flow through the food webs along this river continuum.4. The dominant food resource consumed also changed along the gradient. Leaf detritus consumption decreased from 58% of the total consumption upstream to 6% downstream, whereas consumption of amorphous detritus increased from 18 to 64%. The proportion of animal material consumed also increased from 3 to 27%. The total consumption of autochthonous resources (diatoms and filamentous algae) increased along the continuum (from 6.41 to 34.05 g m−2 year−1). We conclude that these results are related to variation in resource availability, dietary shifts and invertebrate secondary production. These results link resource availability to energy flow, a relationship originally suggested by the RCC.