Aquatic Ecology

Chamberlain, Debbie A.; Possingham, Hugh P.; Phinn, Stuart R.

doi: 10.1007/s10452-021-09896-9pmid: N/A

Marine-protected areas are designated to reduce anthropogenic impacts on biodiversity and enhance fish production, but other ecological processes are inadequately accommodated in plans for coastal and marine ecosystems. We conducted a quantitative systematic literature review and meta-analysis on how researchers and decision-makers include ecological processes in coastal and marine conservation planning. Marine spatial planning ideally delivers representative protected areas systems that deliver persistence for ecosystems and species. Although several reviews have reported on incorporating connectivity as a process in marine spatial planning, to our knowledge, no one has yet published an inclusive review on how ecological processes are incorporated to help ensure persistence in coastal and marine planning. A total of 162 peer-reviewed journal research papers and 27 non-peer-reviewed papers (n = 189) were identified that included ecological processes in coastal and marine conservation planning between 2000 and 2019, the number of papers integrating ecological processes peaked in 2013 followed by a declining trend to 2019. We attribute the trend to the complexity of the problem of integrating dispersal and demographic objectives alongside other management goals. The results of our statistical analysis uncovered that incorporating ecological processes in conservation planning is important for coastal and marine ecosystems across the literature (p-value < 0.001). However, there was significant variation in scope and choice of method in planning assessments. Dispersal was the process most frequently incorporated in spatial plans, followed by demography and flows of nonliving materials. Identifying appropriate ecosystem objectives and incorporating multiple sources of uncertainty into conservation planning for coastal and marine ecosystems remain important areas for future research. This review highlights the need for greater awareness among planners of the relevance of ecological processes in conservation planning for coastal and marine ecosystems.

Perroca, Júlia Fernandes; Nogueira, Caio Santos; Carvalho-Batista, Abner; Costa, Rogerio Caetano

doi: 10.1007/s10452-021-09889-8pmid: N/A

We investigated the population structure, sex ratio, growth parameters, longevity and natural mortality (M) of a hololimnetic population of the Amazon River prawn Macrobrachium amazonicum that presents different morphotypes. Sampling was performed monthly from May 2017 to April 2018 in a water reservoir in the municipality of Severínia, São Paulo, southeast Brazil. Juveniles, ovigerous females (OF) and males (except the morphotypes GC2) were more abundant in the dry season. The overall and seasonal sex ratio leaned toward males. Males were also more abundant in the larger size classes. Growth parameters for males and females were CL∞ = 19.98 mm and 16.94 mm, k = 4.42 year−1 and 3.94 year−1, t0 = -0.3762 and 0.0628, respectively. Longevity was 1.04 years for males and 1.17 years for females, and M was 4.43 year−1 for males and 3.94 year−1 for females. The OF sampled presented smaller sizes in comparison to those registered in the literature, which may be because they reach sexual maturity sooner than in other localities. Males attained larger asymptotic sizes than females; however, their increased growth rate resulted in lower longevity and higher M. High M values among larger males can occur due to disputes over territory, food, and females, while smaller males are often cannibalized. Both sexes presented low longevity, intense growth rates and small asymptotic sizes in comparison to those registered in the literature, which is likely due to high instability in the system caused by environmental variations and anthropic influences.

Olivares-Ferretti, Pamela; Chavez, Viviana; Hernandez, Klaudia; Peredo-Parada, Matías; Parodi, Jorge

doi: 10.1007/s10452-021-09890-1pmid: N/A

The invasive diatom Didymosphenia geminata (Lyngbye) Schmidt, D. geminata has invaded the austral zone of Chile, causing significant ecological, scientific and societal concerns. We aimed to evaluate the viability and motility of Daphnia magna (D. magna), as a biosensor for effects of D. geminata. Toxicity assays were performed in dilutions of river water alone (V/V dilution) and in river water contaminated with D. geminata (V/V dilution) or polyphenols extracted from D. geminata under controlled conditions and different time (acute 30 min and 7 h). Our results indicated that D. magna was sensitive to increasing concentrations of D. geminata extracts. We observed a 50% (IC50) viability reduction after 24 h of exposure to a 0.023 V/V dilution and the same value when using polyphenols from D. geminata; additionally, this treatment further reduced the motility capacity by 50% after 72 h. The D. magna organisms were acutely responsive, showing a 50% reduction in frequency at 15 min. We conclude that D. magna is sensitive to polyphenols produced by D. geminata in rivers, suggesting potential chronic toxic consequences on several aquatic species following exposure to these diatom substances.

Oliveira, Ricardo; Martínez, Aingeru; Gonçalves, Ana Lúcia; Canhoto, Cristina

doi: 10.1007/s10452-021-09891-0pmid: N/A

The decomposition of leaf litter is a key ecological process in stream ecosystems. Leaf traits, variable across species and within species, constitute a prime driver of this process. Vitis vinifera, the most valuable horticultural crop in the world, represent a priviledged opportunity to assess the importance of intra-specific leaf variability on litter decomposition due to its high phenotypical diversity across cultivars. This study aims to assess the importance of leaf trait differences of four Vitis vinifera cultivars (Aragonez, Baga, Bical and Fernão Pires) on mass loss and microbial and detritivore descriptors, in a low order stream. Results indicate that leaf trait variability among cultivars is a main driver of leaf mass loss and microbial decomposers activity. Fungal sporulation rates were reduced in leaves from cultivars more defended by structural defenses—thoughness, higher leaf mass per area and trichomes density. Invertebrates’ structure and density of shredders responded to leaf N concentrations more than leaf structural descriptors. Macroinvertebrates seem to play a crucial role as decomposition facilitators, by accelerating fungal colonization and conidial release, particularly in cultivars endowed with a dense indumentum. Our results indicate that V. vinifera leaf litter is a high-quality substratum that may present narrow intra-specific leaf traits variability, determined by distinct cultivar genetics, which are able to modulate the litter decomposition process in streams. We suggest that further research assessing the effects of vegetation alterations on stream ecosystem functioning should include leaf litter intra-specific dissimilarities that, even when subtle, may propagate from terrestrial to aquatic systems with cascading impacts across the stream food chains.

DiGiacopo, Devin G.; Hua, Jessica

doi: 10.1007/s10452-021-09893-ypmid: N/A

Wetland plant communities are changing rapidly due to a wide range of human activities. The deposition of leaf litter from novel plant communities can alter both the chemical and physical habitat of aquatic ecosystems. Lesser understood are the ecological consequences of novel leaf litter inputs in aquatic communities. Toward this goal, we used two plant invasion scenarios (comparing native black huckleberry to exotic autumn olive and native swamp loosestrife to exotic purple loosestrife) to simulate a shift in wetland plant communities. In this study, we investigated the effects of novel leaf litter leachates on three aquatic ecological interactions: intraspecific competition, predation and parasitism. We examined how leaf litter leachates influence the interactions of American toad larvae (Anaxyrus americanus) with their conspecifics, a dragonfly predator (Anax spp.) and a trematode parasite (Echinostomatidae). We found that leaf litter type influenced competitive interactions only for the huckleberry versus autumn olive comparison. We did not detect any effects of leaf litter type on predator–prey interactions. Finally, litter type strongly influenced host–parasite interactions for both leaf litter comparisons, altering host susceptibility, parasite survival and net infection rates. These results highlight the breadth of potential ecological repercussions of shifting wetland plant communities for native ecosystems.

Li, Lanxin; Zhang, Wenwen; Zhang, Mengzeng; Zhang, Guozhi; Hu, Xinxin; Liu, Chuang; Cao, Xin; Liang, Wenyan

doi: 10.1007/s10452-021-09894-xpmid: N/A

Water shortages make the reclaimed water widely used in urban parks. Due to the residual pollutants, phytoremediation is often carried out in water bodies. In this study, an urban park was selected to study the practical effects of phytoremediation by comparing the water quality in different seasons and water areas. Chemical oxygen demand (COD), total nitrogen (TN), ammonia nitrogen (NH4+–N), total phosphorus (TP), and dissolved organic matter (DOM) were detected. The spatial analysis of pollutants was performed using kriging interpolation in Arc GIS. Hydrophytes species and planting area were also investigated. The results showed that phytoremediation effectively reduced the concentrations of TN and TP in waters all year round. Except in summer, phytoremediation also presented excellent removal of COD and NH4+–N. However, the removal effects of COD and NH4+–N were relatively inadequate in summer due to the rainfall and runoff. Submerged plants played a more important role than emerged plants in water restoration. Especially in winter, the growth of submerged plants guaranteed the removal of nutrient substances. Parallel factor analysis of fluorescent spectra displayed three components in the DOM, namely tryptophan-like (C1), humic-like (C2), and tyrosine-like substances (C3). The spring samples contained C1 and C2, while there was additional C3 in summer samples. The fluorescence intensities of C1, C2, and C3 were stronger in the area with higher plant density, which also reflected the high number of adsorbed microorganisms and was beneficial to degradation and removal of pollutants.

Xu, Chao; Wang, Hai-Jun; Li, Yan; Xu, Chi; Yu, Qing; Liu, Miao; Zhang, Miao; Wang, Hong-Zhu; Hamilton, David P.; Jeppesen, Erik

doi: 10.1007/s10452-021-09899-6pmid: N/A

Loss of submerged macrophytes resulting from high turbidity has become a global environmental problem in shallow lakes, associated with eutrophication. To help macrophyte recovery, application of artificial light-emitting diodes (LEDs) has been proposed to complement nutrient load reductions. We set up a mesocosm experiment to test if LEDs could compensate for shading effects from phytoplankton. We incubated three submerged macrophytes (Vallisneria natans, Myriophyllum spicatum and Ceratophyllum demersum) in 12 tanks of 1000 L under three artificial LED light treatments (red, blue and white) for 94 days in summer. The results showed that 1) growth of V. natans and M. spicatum was stimulated in all the LED light treatments, while C. demersum died in the end of the experiment in all treatments. The growth variables (MLShoot, DMShoot) of V. natans in blue, red and white treatments were 1.8–4.5 times greater than those in the control treatment. For M. spicatum, all plants only survived in the treatments with artificial light supplement. 2) Growing status of V. natans was similar among the treatments of different light colors, while M. spicatum grew best in the red light treatment. The results suggest that artificial light, particularly red light, can promote the recovery of submerged macrophytes in waters where impaired light climate would prevent or delay growth of macrophytes and recovery from eutrophication. Further large-scale field studies are, however, needed to fully elucidate the potential of using artificial light to stimulate growth and recovery of submerged macrophytes in shallow lakes.

Pond, Gregory J.; Krock, Kelly J. G.; Ettema, Leah F.

doi: 10.1007/s10452-021-09900-2pmid: 34712099

Documenting flow regimes and the ecology of source headwater streams has gained considerable attention for scientific and regulatory purposes. These streams do not appear on standard maps, and local physiographic and climatologic conditions can control their origins. We investigated macroinvertebrate assemblages seasonally and in relation to flow duration, catchment and habitat variables within 14 source headwaters (< 1 ha) in the Western Allegheny Plateau over a 19-month period. We classified 6 perennial (P) and 8 intermittent (I) streams directly with continuous flow data loggers. Several biological and trait-based metrics could distinguish flow class, but few instream physical measures could. Macroinvertebrate metrics and assemblage dispersion varied seasonally and responded significantly along a gradient of total flow duration. Separate indicator species analyses generated 22 genera and 15 families with significant affinities to P streams. Richness of P-indicator taxa was also strongly correlated with flow duration gradients, and we estimated a total flow duration changepoint at 77% (3 indicator families) followed by a sharp increase in richness. Two rapid field-based flow duration methods (NC Stream Identification index and OH Headwater Habitat Evaluation index) could distinguish upstream ephemeral reaches from P and I reaches, but misclassified P as I more frequently. Our findings highlight that diverse coldwater macroinvertebrate assemblages inhabited extremely small, low-discharge springs in the region, and responded with flow duration. These source headwater habitats are susceptible to human disturbance and should be monitored as is routinely done in larger lotic systems.

Montaña, Carmen G.; Keppeler, Friedrich W.; Laughrey, Clay P.; Schalk, Christopher M.

doi: 10.1007/s10452-021-09902-0pmid: N/A

Environmental and spatial–temporal processes are proposed as important mechanisms regulating permanent pond communities, but comprehensive research of these factors at fine scales (i.e. patches or microhabitats) is still lacking. Here, we investigated environmental, spatial, and temporal variables influencing community structure and diversity (α, β, γ) in pond microhabitats over one annual cycle (i.e. four seasons). Standardized surveys were conducted monthly for one year, and a suite of biotic and abiotic variables were recorded at each microhabitat to test which assembly processes are important in structuring pond communities. As expected, spatial and environmental variables influenced local species organization at both the annual and seasonal scale. The high β diversity among pond microhabitats was mainly attributed to species turnover from one microhabitat to another rather than richness differences. Habitat heterogeneity largely explained the variation on α and β diversity among pond microhabitats. Overall, our results suggest that multiple ecological processes affect community assembly dynamics in permanent ponds. First, the temporal variation on the distribution of species across pond microhabitats that was associated with environmental fluctuations (mainly temperature, dissolved oxygen, substrate composition, and emergent vegetation) inferred that species sorting (i.e. niche-based processes) is an important driver of the observed community patterns, while the spatiotemporal turnover in species composition and density can be explained by colonization and dispersal events occurring within microhabitats. Our study emphasizes the need to include time, space and environmental variables in studies assessing communities in permanent pond systems, as they appear to be related to distinct processes regulating communities at fine scales.

Kalinda, Chester; Chimbari, Moses J.

doi: 10.1007/s10452-021-09903-zpmid: N/A

Bulinus globosus snails inhabiting ephemeral rivers and ponds in sub-Saharan Africa experience seasonal water-level fluctuations and habitat desiccation. These environmental changes can instigate the aestivation of snails as a survival strategy. However, the net effect of these changes on snail population size following a period of desiccation and resuscitation is poorly understood. To lessen this knowledge gap, we evaluated the effects of desiccation on the fecundity and longevity of Bulinus globosus snails under laboratory conditions. The periods of desiccation used were 57, 64, 71 and 78 days. Our results showed that an increase in desiccation time from 57 to 78 days was associated with a twofold reduction in fecundity. Furthermore, the survival time of B. globosus snails decreased linearly with desiccation time. The median survival time of snails exposed to desiccation for 57 and 78 days was 63 days and 35 days, respectively. Reduction in the fecundity and snail survival post-desiccation may lead to population shrinkage of B. globosus.