Browsing by Author "Hampel, Henrietta"

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250-year records of mercury and trace element deposition in two lakes from Cajas National Park, SW Ecuadorian Andes
(2021) Schneider, Tobias; Musa Bandowe, Benjamin; Mestrot, Adrien; Mestrot, Adrien; Hampel, Henrietta; Mosquera, Pablo; Frankl, Lea; Wienhues, Giulia; Vogel, Hendrik; Tylmann, Wojciech; Grosjean, Martin
Historical records of trace elements in lake sediments provide source-to-sink information about potentially toxic pollutants across space and time. We investigated two lakes located at different elevations in the Ecuadorian Andes to understand how trace element fluxes are related to (i) geology, (ii) erosion in the watersheds, and (iii) local point sources and atmospheric loads. In remote Lake Fondococha (4150 m a.s.l.), total Hg fluxes stay constant between ca. 1760 and 1950 and show an approximately 4.4-fold increase between pre-1950 and post-1950 values. The post-1950 increase in fluxes of other trace elements (V, Cr, Co, Ni, Cu, Zn, As, Cd, and Pb) is lower (2.1–3.0-fold) than for Hg. Mostly lithogenic sources and enhanced soil erosion contribute to their post-1950 increase (lithogenic contribution: > 85%, Hg: ~ 58%). Average post-1950 Hg fluxes are approximately 4.3 times higher in peri-urban Lake Llaviucu (3150 m a.s.l.) than in the remote Lake Fondococha. Post-1950 fluxes of the other trace elements showed larger differences between Lakes Fondococha and Llaviucu (5.2 < 25–29.5-fold increase; Ni < Pb–Cd). The comparison of the post-1950 average trace element fluxes that are derived from point and airborne sources revealed 5–687 (Hg–Pb) times higher values in Lake Llaviucu than in Lake Fondococha suggesting that Lake Llaviucu’s proximity to the city of Cuenca strongly influences its deposition record (industrial emissions, traffic, caged fishery). Both lakes responded with temporary drops in trace element accumulations to park regulations in the 1970s and 1990s, but show again increasing trends in recent times, most likely caused by increase in vehicular traffic and openings of copper and gold mines around Cajas National Park.
A 150-year record of polycyclic aromatic compound (PAC) deposition from high Andean Cajas National Park, southern Ecuador
(2018) Musa Bandowe, Benjamin; Frankl, Lea; Grosjean, Martin; Tylmann, Wojciech; Mosquera, Pablo; Hampel, Henrietta; Schneider, Tobias
The temporal profiles of polycyclic aromatic compounds (PACs) in lake sediments reflect past changes in emissions, transport and deposition of these pollutants and, thus, record natural and anthropogenic processes. We document fluxes of PACs [(polycyclic aromatic hydrocarbons (PAHs), oxygenated PAHs (OPAHs) and azaarenes (AZAs)] deposited in two tropical high-altitude lakes in the CajasNational Park (Ecuadorian Andes, 2°50′S, 79°10′ W). In remote and high elevation Laguna Fondococha (4130 m a.s.l.), the temporal fluxes of OPAHs and AZAs were similar to those of PAHs suggesting similar sources. A significant increase of PAC deposition after the 1950s reflects Ecuador's economic development. PAH fluxes were relatively low (Σ27PAHs (without retene and perylene): 0.86–11.21 ng cm−2 yr−1) with a composition pattern typical for long-range atmospheric transport (high 9-fluorenone/fluorene ratios) and biomass burning (30% lowmolecularweight PAHs). PAHs diagnostic of high temperature combustion (industry, traffic) make up 20–25% of total PAHs. Perylene concentrations increase linearly with increasing sediment depth suggesting diagenetic in-situ production. At lower elevations (Laguna Llaviucu, 3140 m a.s.l.) and closer to urban areas, PAC fluxes in the past decades were 4–5 times higher than in the remote high-elevation lake. Laguna Llaviucu also showed higher concentrations of high molecular weight pyrogenic PAHs and a greater diversity of AZAs. Individual OPAHs and AZAs reflect mainly combustion activities. In Laguna Llaviucu, which is at a lower elevation (3140 m a.s.l.) and closer to the city, molecular ratios suggest short-range atmospheric transport and deposition of PACs.A very foggy climate (170 rainy days per year) with the precipitation maximum at 3500 m removes PACs very efficiently (by wet deposition) from the atmosphere at very short distances from emission sources. This partly explains why L. Llaviucu shows higher fluxes of PACs than the higher elevation L. Fondococha. This study presents the first historical record of organic pollutants from environmental archives in Ecuador.
A simple approach to account for stage–discharge ucertainty in hydrological modelling
(2022) Vázquez Zambrano, Raúl Fernando; Hampel, Henrietta
The effect of stage–discharge (H-Q) data uncertainty on the predictions of a MIKE SHE-based distributed model was assessed by conditioning the analysis of model predictions at the outlet of a medium-size catchment and two internal gauging stations. The hydrological modelling was carried out through a combined deterministic–stochastic protocol based on Monte Carlo simulations. The approach considered to account for discharge uncertainty was statistically rather simple and based on (i) estimating the H-Q data uncertainty using prediction bands associated with rating curves; (ii) redefining the traditional concept of residuals to characterise model performance under H-Q data uncertainty conditions; and (iii) calculating a global model performance measure for all gauging stations in the framework of a multi-site (MS) test. The study revealed significant discharge data uncertainties on the order of 3 m3 s−1 for the outlet station and 1.1 m3 s−1 for the internal stations. In general, the consideration of the H-Q data uncertainty and the application of the MS-test resulted in remarkably better parameterisations of the model capable of simulating a particular peak event that otherwise was overestimated. The proposed model evaluation approach under discharge uncertainty is applicable to modelling conditions differing from the ones used in this study, as long as data uncertainty measures are available.
Abundance and morphometry changes across the high mountain lake-size gradient in the tropical Andes of Southern Ecuador
(2017) Mosquera Vintimilla, Pablo Vernardo; Hampel, Henrietta; Vázquez Zambrano, Raúl Fernando; Alonso , Miguel; Catalan , Jordi
The number, size, and shape of lakes are key determinants of the ecological functionality of a lake district. The lake area scaling relationships with lake number and volume enable upscaling biogeochemical processes and spatially considering organisms’ metapopulation dynamics. These relationships vary regionally depending on the geomorphological context, particularly in the range of lake area <1 km2 and mountainous regions. The Cajas Massif (Southern Ecuador) holds a tropical mountain lake district with 5955 water bodies. The number of lakes deviates from a power law relationship with the lake area at both ends of the size range; similarly to the distributions found in temperate mountain ranges. The deviation of each distribution tail does not respond to the same cause. The marked relief limits the size of the largest lakes at high altitudes, whereas ponds are prompt to a complete infilling. A bathymetry survey of 202 lakes, selected across the full-size range, revealed a volume-area scaling coefficient larger than those found for other lake areas of glacial origin but softer relief. Water renewal time is not consistently proportional to the lake area due to the volume-area variation in midsize lakes. The 85% of the water surface is in lakes >104 m2 and 50% of the water resources are held in a few ones ( 10) deeper than 18 m. Therefore, midlakes and large lakes are by far more biogeochemically relevant than ponds and shallow lakes in this tropical mountain lake district.
Abundance and morphometry changes across the high-mountain lake-size gradient in the tropical Andes of Southern Ecuador
(BLACKWELL PUBLISHING LTD, 2017-08-01) Hampel, Henrietta; Vázquez Zambrano, Raúl Fernando
The number, size, and shape of lakes are key determinants of the ecological functionality of a lake district. The lake area scaling relationships with lake number and volume enable upscaling biogeochemical processes and spatially considering organisms' metapopulation dynamics. These relationships vary regionally depending on the geomorphological context, particularly in the range of lake area <1 km2 and mountainous regions. The Cajas Massif (Southern Ecuador) holds a tropical mountain lake district with 5955 water bodies. The number of lakes deviates from a power law relationship with the lake area at both ends of the size range; similarly to the distributions found in temperate mountain ranges. The deviation of each distribution tail does not respond to the same cause. The marked relief limits the size of the largest lakes at high altitudes, whereas ponds are prompt to a complete infilling. A bathymetry survey of 202 lakes, selected across the full-size range, revealed a volume-area scaling coefficient larger than those found for other lake areas of glacial origin but softer relief. Water renewal time is not consistently proportional to the lake area due to the volume-area variation in midsize lakes. The 85% of the water surface is in lakes >104 m2 and 50% of the water resources are held in a few ones (?10) deeper than 18 m. Therefore, midlakes and large lakes are by far more biogeochemically relevant than ponds and shallow lakes in this tropical mountain lake district.
An annotated checklist of the freshwater cladocerans (Crustacea: Branchiopoda: Cladocera) of Ecuador and the Galapagos Islands
(2018) López, Carlos; Hampel, Henrietta
An annotated checklist of recorded species of Cladocera (Crustacea: Branchiopoda) from inland aquatic habitats in Ecuador (including the Galápagos) is provided. We revised all published records, evaluated the validity of each taxon and provided short taxonomic and biogeographical remarks for each taxon. A total of 34 valid species grouped into 23 genera was found. Presently, all attempts to analyze distributional patterns of cladocerans in Ecuador are premature due to the scarcity of adequate information. Current achievements in the inventory of cladocerans, information gaps and recommendations for future studies on cladoceran taxonomy in Ecuador are discussed.
Assessing the performance of SHETRAN simulating a geologically complex catchment
(2022) Vázquez Zambrano, Raúl Fernando; Birkinshaw, Stephen J.; Hampel, Henrietta; Brito Soliz, Josue Eduardo
Despite recent progress in terms of cheap computing power, the application of physically-based distributed (PBD) hydrological codes still remains limited, particularly, because some commercial-license codes are expensive, even under academic terms. Thus, there is a need for testing the performance of free-license PBD codes simulating complex catchments, so that cheap and reliable mechanistic modelling alternatives might be identified. The hydrology of a geologically complex catchment (586 km2) was modelled using the free-license PBD code SHETRAN. The SHETRAN evaluation took place by comparing its predictions with (i) discharge and piezometric time series observed at different locations within the catchment, some of which were not taken into account during model calibration (i.e., multi-site test); and (ii) predictions from a comparable commercial-license code, MIKE SHE. In general, the discharge and piezometric predictions of both codes were comparable, which encourages the use of the free-license SHETRAN code for the distributed modelling of geologically complex systems.
Biomasa foliar, desfronde y descomposición de la hojarasca en los rodales de Polylepis reticulata del Parque Nacional Cajas
(2015) Pinos Flores, Juan Andrés; Hampel, Henrietta; Gracía Alonso, Carlos
In this study we analyzed leaf litterfall (falling leaves), leaf turnover and the process of litter decomposition of Polylepisreticulata in 6 permanent unlogged sample plots, 100m², located in the Cajas National Park (Cuenca, Azuay) for a period of 9 months. To measure leaf litterfall, five circular collectors (0.125m² opening; 2mm mesh size) were distributed in each plot and contents collected every 15 days. Decomposition bags (dimensions 15 x 15 cm; 2mm mesh size) with about 20g (dry weight) of litterfall, were placed in the soil covered with moss and litter. The bags were collected in periods of 30, 60, 90, 150 and 210 days. Mean annual litterfall for Polylepisreticulata was 3.85 Tons/ha and leaf turnover was 1.75 years. The maximum leaf production was in the month of May and was 4 times greater than the minimum. In 210 days, the decomposition bags lost 20% of its mass and resulted in a rate of 0.40 year-1.
Branquiópodos de las masas de agua lacustre del Parque Nacional Cajas (Andes Australes, Ecuador) inventario y notas autoecológicas
(Universidad de Cuenca, 2017) Alonso, Miguel; Mosquera, Pablo; Hampel, Henrietta; Vázquez, Raúl F.
Extensive sampling of 202 lentic water bodies (lakes, lagoons and ponds) located between 3150 and 4460 m a.s.l. in the Cajas National Park (South Ecuadorian Andes) has revealed the high interest of these mountain enclaves in tropical latitudes for the investigation of faunal and ecological aspects of the branchiopod fauna. The first results allowed to recognize 21 species, 15 of them new to Ecuador, of which 2 are in process of description to be published as new to science. All species are characteristic of little mineralized and oligotrophic waters, 8 of them appear in the plankton and the rest in the limnetic littoral benthos.
Branquiópodos de las masas de agua lacustre del Parque Nacional Cajas (Andes Australes, Ecuador) inventario y notas autoecológicas
(2017) Alonso Garcia-amilivia, Miguel Null; Mosquera, Pablo; Hampel, Henrietta; Vázquez Zambrano, Raúl Fernando
Extensive sampling of 202 lentic water bodies (lakes, lagoons and ponds) located between 3150 and 4460 m a.s.l. in the Cajas National Park (South Ecuadorian Andes) has revealed the high interest of these mountain enclaves in tropical latitudes for the investigation of faunal and ecological aspects of the branchiopod fauna. The first results allowed to recognize 21 species, 15 of them new to Ecuador, of which 2 are in process of description to be published as new to science. All species are characteristic of little mineralized and oligotrophic waters, 8 of them appear in the plankton and the rest in the limnetic littoral benthos.
Challenges for a sustainable management of Ecuadorian water resources
(2015) Nolivos Alvarez, Indira Yadira; Villacís, Marcos; Vázquez Zambrano, Raúl Fernando; Mora Serrano, Diego Esteban; Dominguez Granda, Luis Elvin; Hampel, Henrietta; Velarde, Elizabeth
This paper depicts opinions that condense the thinking of different sectors (i.e., academia, government, private sector, etc.) dealing in certain degree with the management of Ecuadorian water resources. Particularly, the manuscript echoes the main conclusions of a national Workshop that was held in Quito by mid 2014, about the sustainable use of water resources in Ecuador, with the purpose of proposing a research agenda adapted to the priority needs of governmental agencies. The paper discusses several key issues for the management of Ecuadorian water resources such as the urgent need for an active involvement of the national academy into the problem analysis/solving process for water management purposes, in a view of sustainable development, and as a way of warranting the effectiveness of the national policy for development oriented research that the current government is promoting. Herein, there is a need for complementing this policy by promoting a national system that foster communication between the water governmental institutions and the scientific community in terms of opportunities (financial and logistical) for scientific research in water resources and stakeholders engagement. Further, the paper stresses the urgent need of gathering and structuring all relevant knowledge/information/data into a unique repository for decision support that relies on auxiliary tools such as Geographical Information Systems (GIS), numerical modelling and associated uncertainty analyses, etc.; this in conjunction with the establishment and maintenance of a national monitoring network of water resources related environmental variables.
Community structure and functional feeding groups of macroinvertebrates in pristine andean streams under different vegetation cover
(2020) Vimos Lojano, Diego José; Hampel, Henrietta; Vázquez Zambrano, Raúl Fernando; Martinez Capel, Francisco
© 2020 European Regional Centre for Ecohydrology of the Polish Academy of Sciences As a function of the dominant vegetation cover, patterns of variation in the structure and composition of both, the aquatic macroinvertebrate communities and their functional feeding groups (FFG) were examined at pristine streams of two high Andean micro-catchments of southern Ecuador. Ten sampling segments were defined in the study streams surrounded by either Tussock grass (TG), Quinua forest (QF) or high mountain forest (HMF). In each segment, environmental and biological samples were collected. Different statistical analyses were implemented for assessing possible relationships between biological and environmental variables. TG and QF streams were found to share many physical and biological characteristics. HMF ecosystems, which are characterised by greater total hardness, water velocity, temperature, pH and nitrite/nitrate concentrations exhibited low values of diversity, richness, relative abundance of non-insects, piercer and parasites. Further, high values of relative abundance of Plecoptera (predators) were observed in HMF, apparently due to higher water velocities and their resistance to these flow conditions. The composition of the macroinvertebrate community showed similarity in TG and QF. It was observed at the three study sites a dominance of organisms generally tolerant to lower availability of oxygen (Chironomidae and non-insect class) and, curiously, to higher concentrations of nutrients. It was found some taxa associated with the presence of organic matter in the sediment because they use allochthonous resources (Phylloecus).
Crustáceos bentónicos y macrófitos como indicadores de calidad ecológica en los lagos de los Andes Australes de Ecuador
(Universidad de Cuenca, 2017) Alonso, Miguel; Mosquera, Pablo; Hampel, Henrietta; Vázquez, Raúl F.
The taxonomic composition of the litoral benthic limnetic crustacean communities, (branchiopods, copepods and ostracods) and macrophytes of the lacustrine water bodies of the Cajas National Park located in the Southern Andes of Ecuador have been studied in order to identify the most suitable taxa to be used as indicators of the ecological status of lakes. Among the crustaceans (22 taxa) three groups were differentiated. A first group with taxa of higher indicator value including Branchinecta papillata, Ilyocryptus spinosus, Alonella sp, Pleuroxus sp. Paralona pigra and Alona sp. gr. manueli. A second group with medium indicator value including Alona glabra, Alona guttata, Microcyclops sp. Eucyclops sp. and Paracyclops sp. The third group was formed by taxa of the lower indicator value, either because of its eurioic and / or cosmopolitan character or because of its rarity. Macrophytes have been evaluated as good indicators of the ecological and conservation status of the lakes. The taxa which were submerged, floating and rooted in the sediment were identified to be a good indicator for the water body, and helophytes and hygrophytes for the limnetic litoral zone.
Crustáceos bentónicos y macrófitos como indicadores de calidad ecológica en los lagos de los Andes Australes de Ecuador
(2017) Alonso Garcia-amilivia, Miguel Null; Mosquera, Pablo; Hampel, Henrietta; Vázquez Zambrano, Raúl Fernando
The taxonomic composition of the litoral benthic limnetic crustacean communities, (branchiopods, copepods and ostracods) and macrophytes of the lacustrine water bodies of the Cajas National Park located in the Southern Andes of Ecuador have been studied in order to identify the most suitable taxa to be used as indicators of the ecological status of lakes. Among the crustaceans (22 taxa) three groups were differentiated. A first group with taxa of higher indicator value including Branchinecta papillata, Ilyocryptus spinosus, Alonella sp, Pleuroxus sp. Paralona pigra and Alona sp. gr. manueli. A second group with medium indicator value including Alona glabra, Alona guttata, Microcyclops sp. Eucyclops sp. and Paracyclops sp. The third group was formed by taxa of the lower indicator value, either because of its eurioic and / or cosmopolitan character or because of its rarity. Macrophytes have been evaluated as good indicators of the ecological and conservation status of the lakes. The taxa which were submerged, floating and rooted in the sediment were identified to be a good indicator for the water body, and helophytes and hygrophytes for the limnetic litoral zone.
Deforestation and benthic indicators: How much vegetation cover is needed to sustain healthy Andean streams?
(2014-08-22) Hampel, Henrietta
Deforestation in the tropical Andes is affecting ecological conditions of streams, and determination of how much forest should be retained is a pressing task for conservation, restoration and management strategies. We calculated and analyzed eight benthic metrics (structural, compositional and water quality indices) and a physical-chemical composite index with gradients of vegetation cover to assess the effects of deforestation on macroinvertebrate communities and water quality of 23 streams in southern Ecuadorian Andes. Using a geographical information system (GIS), we quantified vegetation cover at three spatial scales: the entire catchment, the riparian buffer of 30 m width extending the entire stream length, and the local scale defined for a stream reach of 100 m in length and similar buffer width. Macroinvertebrate and water quality metrics had the strongest relationships with vegetation cover at catchment and riparian scales, while vegetation cover did not show any association with the macroinvertebrate metrics at local scale. At catchment scale, the water quality metrics indicate that ecological condition of Andean streams is good when vegetation cover is over 70%. Further, macroinvertebrate community assemblages were more diverse and related in catchments largely covered by native vegetation (>70%). Our results suggest that retaining an important quantity of native vegetation cover within the catchments and a linkage between headwater and riparian forests help to maintain and improve stream biodiversity and water quality in Andean streams affected by deforestation. This research proposes that a strong regulation focused to the management of riparian buffers can be successful when decision making is addressed to conservation/restoration of Andean catchments. © 2014 Iñiguez-Armijos et al.
Dendrochronological analysis and growth patterns of polylepis reticulata (Rosaceae) in the ecuadorian andes
(2019) Alvites, Cesar Ivan; Battipaglia, Giovanna; Santopuoli, Giovanni; Hampel, Henrietta; Vázquez Zambrano, Raúl Fernando; Matteucci, Giorgio; Tognetti, Roberto
Relict tree species in the Andean mountains are important sources of information about climate variability and climate change. This study deals with dendroclimatology and growth patterns in Polylepis reticulata Hieron., growing at high elevation (mean of 4000 m a.s.l.) in three sites of the Ecuadorian Andes. The aims of the research were: (i) characterizing tree-ring boundaries; (ii) describing tree-ring patterns of the study sites; (iii) investigating the relationships between climate and radial tree growth; and (iv) determining the spatial correlation between seasonal climatic factors and tree-ring width of P. reticulata. Tree rings were characterized by semi-ring porosity and slight differences in fibre wall thickness between latewood and subsequent earlywood. In all sampling sites, tree rings in heartwood were more clearly visible than in sapwood. Tree-ring width was more related to temperature than to precipitation, with growth being also affected by site conditions and stand structure, as well as other local factors. No significant relationships were found between tree-ring chronologies of P. reticulata and El Niño-Southern Oscillation (ENSO) and Vapour Pressure Deficit indices. The study highlights that there is not a clear driving climate factor for radial growth of P. reticulata. Additional research is needed to study growth dynamics of this species and the impacts of local environmental variables.
Estructura de los rodales de polylepis reticulata del Parque Nacional El Cajas. Estado actual para proyección futura en el marco del cambio climático
(2015) Pacheco León, Karla Antonieta; Hampel, Henrietta
This research aimed to describe the structure of Polylepisreticulata stands in Cajas National Park (P.N.C.), to provide accurate information on the current status of these forests and to contribute a baseline to the development of a future project that will analyze the ecophysiology of Polylepis and the functional responses to climate change. Six permanent plots were selected (3800 – 4000 m a.s.l) in three different areas: Toreadora lake, Taquiurco Hill and San Luis Forest. Structural variables such as: density, diameter at breast height (DBH), growth rates of trees, aboveground biomass, content and carbon accumulation rates, Specific Leaf Weight (SLW), Leaf Area (LA) and Leaf Area Index (LAI) were determined. Further, self-thinning law was known. When possible these variables were measured directly in field, however indirect methods were adopted when direct measurement would have been too invasive and/or expensive. Allometric equations were developed from field data to estimate biomass, growth rates, leaf area and others. Global mean density was 4025 trees/ha with aboveground biomass of 102.55 Mg/ha, 50% of which is carbon. Increases found for Polylepis are very slow and ranged from 0.04 to 0.55 mm/year. Annual production was 1.11 Mg/ha. The results show that the 70 % of absorbed carbon is used for the production and maintenance of the leaves.
Evaluating the Ecological Status of Fluvial Networks of Tropical Andean Catchments of Ecuador
(2023) Vázquez Zambrano, Raúl Fernando; Hampel, Henrietta
In the tropical high mountains, human activities have strongly intensified in recent decades. Agricultural frontier movement toward higher elevations, river channel modifications, mining, and urban waste discharge threaten river ecosystem health, which is even more alarming when drinking water supply comes from surface water. The aim of the current study was to evaluate the ecological status of high mountain fluvial networks of tropical Andean catchments based on the definition of different river types. Physical–chemical variables and macroinvertebrate communities were sampled in 90 stations of seven tropical high mountain catchments. River habitat and riparian vegetation quality were further evaluated. K-means classification, using physical and hydro-morphological characteristics, identified six different river types. This classification was further refined to five river types by the analyses of macroinvertebrate communities through multidimensional scaling and analysis of similarity. The anthropogenic pressure gradients, present in the different river types, were inorganic (i.e., conductivity, turbidity), organic (i.e., fecal coliforms), river habitat, and riparian vegetation quality. Macroinvertebrate communities responded to different environmental variables in the páramo, mountain forest with humid shrub, urban, and Tarqui river types. Heterogeneous fluvial habitats and high altitude favored taxa such as Atanatolica, Mortoniella, Helicopsyche, Anacroneuria, Paltostoma, Helicopsyche, Paltostoma, Atopsyche, Pheneps, and Maruina. Chironomidae and Psychoda dipteran were associated with higher biochemical oxygen demand, lower oxygen concentration, high fecal coliforms, and total dissolved solids, while Haitia was linked to elevated nitrate concentrations. Integrated watershed management could benefit from a well-established biomonitoring network, considering different river types, which represents the natural variability of the ecosystems, as well as anthropogenic pressure gradients.
Genetic isolation among mountains but not between stream types in a tropical high-altitude mayfly
(BLACKWELL PUBLISHING LTD, 2016-05-01) Finn, Debra Suzanne; Hampel, Henrietta
Glaciers that directly feed high-altitude streams create unique environmental conditions that contribute substantially to regional-scale lotic habitat diversity and biodiversity, including intra-specific genetic diversity (as population structure) between glacier-fed and other types of streams (e.g. groundwater-fed). However, these population-genetic patterns are thus far only understood for macroinvertebrates in the temperate zone, where strong seasonality and narrow temporal windows for emergence and mating could help drive patterns of genetic differentiation between streams with contrasting temperature, flow, or other environmental characteristics influencing life-history patterns. Our primary objective was to assess population-genetic structure between groundwater-(GW) and glacier runoff-fed (RO) streams in high-altitude tropical (relatively aseasonal) basins of the Ecuadorian Andes. Our focal species was Andesiops peruvianus, a baetid mayfly confamilial with well-studied temperate alpine mayflies. We pursued secondary objectives of evaluating broader scale population-genetic patterns across mountain ranges for the first time in high-altitude tropical streams, and evaluating genetic evidence for recovery from population bottlenecks in this volcanically active region. For the primary objective, we collected A. peruvianus (mean N = 16.5 per reach) and a suite of environmental variables from six intra-basin pairs of GW/RO stream reaches at altitudes 4000-4300 m a.s.l. on three glaciated volcanoes representing two parallel sub-ranges of the Ecuadorian Andes. We tested for significant GW/RO pairwise differences in haplotype distribution and genetic diversity obtained by sequencing the barcoding region of the mitochondrial cytochrome oxidase I gene. For the broader scale sub-objectives, we added two unpaired populations (total N = 231) and evaluated genetic structure at nested spatial scales of streams/basins/mountains, and we tested for differences between mountains. We also measured Tajima's D and Fu's FS to evaluate evidence for demographic instability at the scale of individual mountains, each with a different volcanic history. We found no evidence for population structure between GW and RO streams within basins. Population structure among basins within mountains was significant, but only in areas where streams occupied deep, physically isolating canyons. Comparisons between all possible pairs of the three mountains revealed significant structure, but pairwise ?ST was an order of magnitude greater between pairs of mountains occupying different ranges than for the pair in the same range. Indeed, no haplotypes were shared between the two Andean sub-ranges. All three mountains, regardless of recent volcanic history, showed a significant signature of recovery from recent bottleneck. Our results suggest that strong environmental differences between glacial runoff and groundwater stream types do not isolate these tropical, high-altitude mayfly populations. Rather, populations are panmictic within basins. Broader scale patterns among mountains suggest that dispersal and gene flow in these tropical streams proceed similarly to temperate alpine systems; that is, relatively strong isolation among mountains but reasonable capacity for gene flow between headwaters in close proximity on a single mountain. A notable difference from the temperate studies is that mayfly populations in Ecuadorian high-altitude streams appear to be demographically unstable, regardless of the recent volcanic eruption history of the mountain they occupy. Frequent eruptions in this volatile region might affect streams across areas more extensive than a single mountain.
Habitat suitability curves for freshwater macroinvertebrates of tropical andean rivers
(2020) Vázquez Zambrano, Raúl Fernando; Vimos Lojano, Diego Jose; Hampel, Henrietta
Sustainable river management requires a thorough understanding of the response of aquatic biota to riverine microhabitat variability. The purpose of this study was to assess macroinvertebrate hydraulic-habitat suitability in Ecuadorian Andean rivers to support habitat modelling for sustainable ecosystem management. 597 macroinvertebrate samples were collected from ten sampling stations the Yanuncay River, Ecuador. Physical, chemical, hydraulic and habitat variables were measured/calculated. Froude number, Reynolds number, substrate index and algae coverage were major drivers of macroinvertebrate response, and were used to develop suitability curves for Baetodes, Andesiops, Camelobaetidius, Ecuaphlebia, Anacroneuria, Atopsyche, Simulium and Palpomyia using General Additive Models. Standardised density contours of taxa as functions of hydraulic and habitat variables were also developed. Taxonomic response was related to body structures/shapes and feeding habits. Baetodoes, Simulium, Anacroneuria and Atopsyche preferred fast flowing waters, and thus, they could be significantly affected in case of flow reduction. Similar habitat suitability curves were developed from the main river and the tributaries, possibly due to the short distance between the sampling stations. This study fills a major knowledge gap by developing macroinvertebrate habitat suitability curves for future physical habitat simulations and environmental flow assessments in the Andean region