Intermittent Streams Research Articles

Species of Wadicosa (Araneae, Lycosidae): a new species from the southeastern Arabian Peninsula

Wadicosa arabica sp. nov. is described from material of both sexes collected in Oman and the United Arab Emirates. The species belongs to the W. fidelis group and differs from its congroupers, inter alia, by the shape of the tegular apophysis and the embolus in the male. The occurrence of W. arabica sp. nov. is restricted to the gravel, pebble and cobble beds of ephemeral and intermittent streams (wadis) in the mountains of the eastern United Arab Emirates and northern Oman (the Hajar Mountains sensu lato). There it is often common and conspicuous alongside areas of surface waters. Notes on its courtship behaviour are given.

Assessing the Influence of Zero‐Flow Threshold Choice for Characterising Intermittent Stream Hydrology

ABSTRACTZero‐flow recordings in gauged streamflow data are critically important for intermittent stream research. Acknowledging the high uncertainty in zero‐flow recordings, many studies pick a small number as zero‐flow threshold, below which the flow is considered to be zero. The choice of zero‐flow threshold is often arbitrary or unjustified, which leads us to wonder: would selecting a slightly different threshold change analysis result significantly? Here, we used a simple sensitivity analysis to assess how the choice of zero‐flow threshold impacts the calculated values of relevant metrics to intermittent stream research. Results show that these metrics tended to be more sensitive to lower zero‐flow thresholds, suggesting that even choosing a slightly different threshold could lead to meaningfully different results from the management perspective. This study highlights the need for reasonable justification of the choice of zero‐flow threshold and concludes with potential ways to reduce uncertainty in zero‐flow measurement.

What Is Relatively Permanent? Flow Regimes of Arizona Streams within the Context of the 2023 Conforming Rule on the Revised Definition of “Waters of the United States”

The classification of stream flow regimes has been a subject of study for over a half century in the fields of hydrology, geomorphology, ecology, and water resources management. But with the most recent Supreme Court decision on jurisdictional Waters of the United States (WOTUS) and the 2023 Conforming Rule, the answer to the question of which waters are relatively permanent has increased in importance and urgency. One state where this question is salient is Arizona, where approximately 95% of its streams are nonperennial. In this study, we use long-term (>30 years) daily discharge records from Arizona to assess semi-natural flow regimes of arid streams within the context of the 2023 Conforming Rule. Using flow percentile distributions, we distinguished flow permanency—ephemeral vs. intermittent vs. perennial—for 70 stream reaches distributed throughout the state. Ephemeral streams had a median flow of 0 cms and a 75th percentile flow permanence less than 25% (i.e., less than 3 months of flow for every 7.5 out of 10 years). On the other end of the spectrum, perennial streams had a 90th percentile flow permanence of 100%. In the middle, intermittent streams had a 75th percentile flow permanence greater than 25% and a 90th percentile flow permanence less than 100%. We also assessed the effect of the recent megadrought (since 1994) on flow permanency. As a result of the megadrought, four perennial streams transitioned to intermittent, four intermittent streams transitioned to ephemeral, and one perennial stream became ephemeral. The flow classification we present here is specific to Arizona streams but could be useful to other arid regions seeking to answer the question of which streams are relatively permanent in a typical year.

Anuran occupancy varies with stream characteristics and flow across Arizona wilderness areas

Abstract Riparian ecosystems comprise less than 2% of the landscape in the arid western United States, yet they provide habitat and resources to over half of arid‐land wildlife species, including a broad diversity of anurans (frogs and toads). Despite this, relatively few studies describe riparian herpetofaunal communities in the Southwest, and remote wilderness areas are particularly undersurveyed. We employed passive acoustic monitoring to capture anuran advertisement calls in wilderness area tributaries of the Verde River, Arizona, USA. In the spring and summer of 2021 and 2022, 13–29 autonomous recording units (ARUs) were deployed along perennial, intermittent and ephemeral tributary stream reaches. We characterized sites based on the per cent of pool, riffle, run and side channel habitat within 100 m of each ARU and quantified substrate, wetted channel width and canopy cover. To relate anuran occupancy to environmental and hydrological variables, we evaluated acoustic detection data using single‐species, single‐season occupancy models. Four species were detected in this study: canyon treefrog (Hyla arenicolor), red‐spotted toad (Anaxyrus punctatus), Woodhouse's toad (Anaxyrus woodhousii) and non‐native American bullfrog (Lithobates catesbeianus), with canyon treefrog being the most ubiquitous species observed. Vocal activity of canyon treefrog was higher at perennial and intermittent sites compared to ephemeral sites, and the presence of pools was most strongly associated with canyon treefrog occupancy. Persistent, slow‐moving water best predicted the presence of breeding canyon treefrogs. Notably, this study did not detect several species with historical records in the middle Verde River catchment, including Arizona toad (Anaxyrus microscaphus) and northern leopard frog (Lithobates pipiens). Given climate change‐related flow declines and intensifying demands for water in arid lands globally, maintaining stream flows that provide consistent and suitable hydroregimes for anuran breeding and larval development is of increasing importance. Determining habitat use and flow regimes necessary to support anuran populations can aid in prioritization of conservation actions related to water management and predict how changes in water availability may impact stream‐breeding anurans.

A unified streamflow drought index for both perennial and intermittent rivers at global scale

ABSTRACT The modelling of streamflow drought is usually performed with different approaches for perennial and intermittent rivers, as no-flow periods require a dedicated statistical treatment. Here, a unified drought index is proposed by extending the threshold method to all flow regimes. The method generalizes the approach commonly adopted for low-flow droughts by accounting for the probability of occurrence in a yearly reference period. Application to a global dataset for 1991–2020, derived from ERA5-forced LISFLOOD model simulations, demonstrates how consistent outcomes can be obtained in all major perennial and intermittent streams. A simplified version of the method is also discussed, detailing how reliable drought detection can be achieved in many parts of the world (e.g. central Europe, the eastern US for low-flow, and northern Russia and the Middle East for no-flow) even when the frequency distribution of the spells in time is replaced by the simpler average number of events.

Hidden results of functional diversity in macroinvertebrates: Trait-groups specific response to flow intermittency in lowland streams

As global flow intermittency increases, understanding how macroinvertebrates respond at a functional level in streams becomes crucial for effective water management. This study investigates the functional response of macroinvertebrates to flow intermittency in Hungarian lowland streams over a 10-month period, comparing intermittent and perennial streams across the entire community, trait groups, and trait states. We aimed to demonstrate differences in functional diversity using metrics such as functional richness, evenness, divergence, dispersion, and Rao's quadratic entropy. For trait groups, we focused on both response and stable traits, anticipating greater differences in response traits. Additionally, we identified which trait states, as indicated by community-weighted means, contribute significantly to variations between streams. Our findings indicate that functional diversity in intermittent streams is generally lower or equivalent to that in perennial streams, suggesting disparities in functional trait composition. Significant differences were observed within trait groups, indicating specific responses of trait groups to intermittency. We identified resilience trait states—including current velocity, reproduction, respiration, female length, locomotion, substrate relation, aquatic stages, and resistance forms—that contributed to these differences. The three-level analysis revealed a hidden relationship: differences at the state level do not consistently manifest at the trait group or whole community levels. Investigating functional changes at the trait group or trait state level can serve as an early indicator of community shifts. Incorporating trait groups as indices into assessment frameworks could facilitate early detection of functional changes during bioassessment. We recommend considering trait groups when evaluating functional responses to flow intermittency in future studies.

Impact of a WWTP effluent overland flow on the properties of a mediterranean riparian soil

In this work we aim to assess the impact of a WWTP effluent overland flow on properties and nutrient concentrations of a riparian soil, in order to explore the potential of this practice as a nature-based treatment. We set two study zones of 150 m2 on the field, one control and one that received the WWTP effluent on its surface for one month. Samples were taken before and after the effluent overland flow system, to test the impact of the effluent on soil properties through a BACI design, and after 17 months, to evaluate the recovery of the soil. Two depths were studied: 0–5 cm and 5–20 cm. The effluent overland flow triggered an increase in exchangeable sodium percentage and a decrease in nitrate concentration in both depths, and an increase in ammonium concentration in 0–5 cm depth. After 17 months, there were not found relevant differences among zones. In conclusion, this practice could be used in the purpose to reduce the nutrient concentrations of WWTP effluents. This practice could be relevant for regions where WWTP effluents are discharged in low-flow or intermittent streams, such as semi-arid regions or the Mediterranean region.

Correlation Between Apical, Anterior, and Posterior Vaginal Wall Prolapse With Voiding Dysfunction: A Single Center Retrospective Cohort Study.

Voiding Dysfunction (VD) is one of the most common disorders among women, which is characterized by a disorder in urination. Pelvic organ prolapse is one of the factors that can affect VD. In this study, the relationship between prolapse in the anterior, posterior, and apical areas and VD has been evaluated. This is a cohort retrospective study. The participants in this study were women with VD, who referred to the pelvic floor disorders clinic of Imam Khomeini Hospital in Tehran in 2018-2020. Clinical information was obtained retrospectively from the hospital's electronic data system, also symptoms (intermittent stream, incomplete voiding, poor flow, post void dribble, straining to void, stage anterior, posterior and apical) and urodynamic parameters (including EMG, PVR100, Qmax12, and pdet20) were evaluated, which included detailed questionnaires (Urinary Distress Inventory 6 (UDI-6) and Incontinence Impact Questionnaire-7 (IIQ-7)), pelvic examination, and complete urodynamic evaluation. There was a direct relationship between the age of the patients and the stage of prolapse (p<0.001). So that, the stage increased with age. In addition, it was found that the severity of urinary symptoms is related to the stage of prolapse in the apical area (p=0.001). Also, the results showed that intermittent stream symptoms and the symptoms of staining to void had a significant relationship with the stage of prolapse (III and IV) in the apical and anterior areas. Also, it was shown that only PVR > 100 had a significant relationship with the stage of prolapse in the apical area (p=0.001). Intermittent stream and straining to void were related to the stages of prolapse in the apical and anterior regions. It was also concluded that the greater the prolapse, the higher the value of PVR > 100.

Fish beta diversity associated with hydrologic and anthropogenic disturbance gradients in contrasting stream flow regimes

Understanding the role of hydrologic variation in structuring aquatic communities is crucial for successful conservation and sustainable management of native freshwater biodiversity. Partitioning beta diversity into the additive components of spatial turnover and nestedness can provide insight into the forces driving variability in fish assemblages across stream flow regimes. We examined stream fish beta diversity across hydrologic and anthropogenic disturbance gradients using long-term (1916–2016) site occurrence records (n = 17,375) encompassing 252 species. We assessed total beta diversity (Sørensen dissimilarity), spatial turnover, and nestedness of fish assemblages in contrasting stream flow regimes across a gradient of decreasing flow stability: groundwater stable (n = 77), groundwater (n = 67), groundwater flashy (n = 175), perennial runoff (n = 141), runoff flashy (n = 255), and intermittent (n = 63) streams. Differences in total beta diversity among the stream flow regimes were driven predominantly (>86 %) by spatial turnover (i.e. species replacement) as opposed to nestedness (i.e. species loss or gain). Total fish beta diversity and spatial turnover were highest in streams with intermediate flow stability (groundwater flashy), while more flow-stable streams (groundwater stable and groundwater) had lower turnover and higher nestedness. Species turnover was also strongly associated with seasonal variation in hydrology across all flow regimes, but these relationships were most evident for assemblages in intermittent streams. Distance-based statistical comparisons showed significant correlations between beta diversity and anthropogenic disturbance variables, including dam density, dam storage volume and water withdrawals in catchments of groundwater stable streams, while hydrologic variables were more strongly correlated with beta diversity in streams with runoff-dominated and flashy flow regimes. The high spatial turnover of species implies that fish conservation actions would benefit from watershed-focused approaches targeting multiple streams with wide spatial distribution, as opposed to simply focusing on preserving sites with the greatest number of species.

Ten-Year Response of Riparian-Associated Songbirds to Implementation of Streamside Management Zones in Watershed-Scale Harvests in the Appalachian Mountains

Abstract Streamside management zones (SMZs) are regulated components of actively managed forests in the eastern United States, but width and overstory retention requirements vary widely among states. Within watershed-scale harvests, we evaluated the relative abundances of three riparian-associated songbirds (Acadian flycatcher, Empidonax virescens; blue-headed vireo, Vireo solitarius; and Louisiana waterthrush, Parkesia motacilla) near Appalachian headwater streams receiving three SMZ treatments representative of a range of current state SMZ regulations in the eastern United States. Prior to harvest, all species were relatively abundant near all stream types, including ephemerals. Abundances of all species were largely similar among SMZ treatments at 3 years and 10 years postharvest and were higher along streams with greater residual canopy cover within 100 m. Forested SMZs as prescribed by current regulations can sustain these species in managed forests up to 10 years postharvest, but abundance appears to be driven largely by canopy cover retention in adjacent stands. Managing habitat for riparian-associated songbirds in harvested watersheds will require expanding the extent of focus beyond the local stream corridor to include consideration of silvicultural systems that retain greater canopy cover in surrounding forests. Where conservation of riparian-associated songbirds is a management objective, SMZ protection should be extended to all streams. Study Implications: The results of this study suggest that forested streamside management zones (SMZs) mandated by contemporary best management practices (BMPs) in Kentucky and other eastern US states can sustain similar abundances of three riparian-associated songbirds in managed watersheds up to 10 years after harvest. Overstory retention in SMZs along perennial and intermittent streams is common across the eastern United States, but state BMPs rarely require retention along ephemeral streams. Target songbird species occupied forests along all stream types prior to harvest, and their postharvest abundances were positively associated with canopy retention within 100 m of streams. If long-term occupancy of managed stands by riparian-associated songbirds is an objective, we recommend using SMZs around all streams, including ephemerals, and implementing at least moderate-retention silvicultural systems in areas within 100 m of streams.

Dry, drier, driest: Differentiating flow patterns across a gradient of intermittency

AbstractIntermittent streams exhibit regular patterns of drying and are widespread, but the patterns of drying among streams within geographic proximity are not fully understood. We compared annual patterns of flow and drying among 10 intermittent streams within a single drainage basin and assessed how traditional hydrologic metrics described variation between streams. We installed stream intermittency sensors and evaluated stage height using low‐cost methods and evaluated landscape factors as potential drivers of flow patterns. Intermittent streams varied based on both high‐ and low‐flow metrics, driven by a variety of landscape‐level factors, especially watershed size. Additionally, we compared the observed flow regimes within our system with predictions generated using an established Soil and Water Assessment Tool, finding that modeled streamflow patterns generally underrepresented observed drying within the system.

Underactive bladder, Fowler's syndrome are potentially curable by uterosacral ligament repair.

Underactive bladder (UAB) is essentially an inability of the bladder to properly empty. UAB symptoms, when they co-occur with posterior fornix syndrome (PFS) symptoms (urge, frequency, nocturia, chronic pelvic pain), can be cured/improved, surgically by uterosacral ligament (USL) repair, non-surgically, by devices which give mechanical support of the USLs or strengthening pelvic muscle and ligaments with squatting-based exercises. The pathogenic pathway from weak USLs to UAB (and PFS) is that, when the muscles which externally open the posterior wall of the urethra contract against lax USLs, their contractile force weakens, and they cannot open the urethra adequately. The detrusor then contracts against a relatively unopened urethra to cause obstructive symptoms (i.e., UAB) such as slow stream, intermittent stream (stopping and starting), hesitancy (difficulty starting), feeling of incomplete emptying, and post-micturition dribble. Co-occurrence of PFS symptoms indicates that UAB may be part of the PFS, with USL causation, which can be tested by a tampon or probe in the posterior fornix. If the emptying (and other) PFS symptoms improve, it is a sign that UAB, and Fowler's syndrome (FS) can potentially be cured or improved by USL repair. Following USL repair, many studies have recorded very significant improvement in emptying symptoms, and objective tests, for example, postvoid residual (PVR), decreased natural bladder volume, and decreased emptying time. FS and UAB are most likely a part of the PFS and, therefore, potentially curable by USL repair.

Local environment and fragmentation by drought and damming shape different components of native and non-native fish beta diversity across pool refuges

Pool refuges are critical for maintaining stream fish diversity in increasingly intermittent streams. Yet, the patterns and drivers of beta diversity of native and non-native fish in pool refuges remain poorly known. Focusing on Mediterranean streams, we decomposed beta diversity of native and non-native fish into richness difference (RichDiff) and species replacement (Repl), and local (LCBD, LCBDRichDiff and LCBDRepl) and species (SCBD) contributions. We assessed the influence of environmental and spatial factors associated with drought and damming fragmentations on beta diversity components and LCBDs, and of local species richness and occupancy on LCBDs and SCBD, respectively. Overall, non-native species showed a more limited occupancy of pool refuges than native fish. RichDiff dominated beta diversity, though it was influenced by drought and damming fragmentations for native fish and local environment for non-native fish. Repl for native fish was slightly influenced by local environment, but for non-native fish was largely driven by drought and damming, albeit with a contribution of local environment as well. LCBD and LCBDRichDiff increased in pools in low order streams for native fish and at low elevations for non-native fish, and with high or low species richness. SCBD was higher for native species with intermediated pool occupancy, but for non-native species with low occupancy. Our results suggest that stream fragmentation may drive native species loss and non-native species replacement in pool refuges, and that environmental filtering may shape non-native species loss. Pools in lower order streams harbouring unique species-rich or species-poor assemblages should be prioritize for conservation and restoration, respectively, and pools at low elevation with unique non-native assemblages should deserve control efforts. We encourage the partitioning of beta diversity and individual analysis of native and non-native fish in intermittent streams, which may be key in stressing the importance of pool refuges in safeguarding native fish diversity.

Resistance not resilience traits structure macroinvertebrate communities in newly drying stream sections

Transitioning from perennial to non-perennial flow regimes causes ecological shifts in aquatic communities. Aquatic macroinvertebrates deploy resistance and resilience strategies to cope with flow intermittency, crucial in rivers with long-term seasonal dry episodes. Less is known, about how these strategies support community persistence in streams that only recently have experienced drying, and where local assemblages lack such adaptations. Our study conducted two four-season campaigns, separated by a one-year break, to assess macroinvertebrate responses in newly drying intermittent streams by comparing intermittent and perennial stream sections. We characterize communities from structural and functional perspectives, and then evaluate the response at the trait state level. We observed a decline in taxa richness and abundance, but not structural diversity, in response to flow intermittency. Resistance traits are more important than resilient traits in structuring macroinvertebrate communities in newly intermittent stream sections. Taxa in intermittent sections exhibit a smaller trait space, indicating lower functional redundancy. The macroinvertebrate response to intermittency lacks a predictable pattern, suggesting time-dependent and trait-state-specific colonization by adapted taxa and community assembly with resistance and resilience strategies. As river drought increases due to climate change, recognizing the temporal dimension becomes crucial for understanding ecological responses to intermittency.

Dual effects of drying and urban pollution on leaf litter decomposition and shredder consumption in permanent and intermittent streams

In the present study we investigated the combined effect of flow intermittence and wastewater treatment plant (WWTP) effluent on leaf litter decomposition in two Mediterranean streams with permanent and intermittent flow regimes. The litter decomposition experiment was performed using black poplar litter bags where we measured litter mass loss, fungal biomass, aquatic hyphomycete sporulation and species richness and C:N ratio. Afterwards, the remaining litter material from the different treatments was offered to the shredder Potamophylax latipennis in a microcosm laboratory experiment, and its growth and consumption rates were studied. We hypothesised that drying would decrease leaf litter decomposition in the permanent stream more than in the intermittent stream and that WWTP effluent would compensate for drying effects when both stressors interacted. The results indicated that drying has the greatest impact on the permanent stream, decreasing decomposition, aquatic hyphomycete species richness, and leaf litter quality. In the intermittent stream, WWTP effluent decreases aquatic hyphomycete species richness, but drying increases it, showing an opposing effect and a synergistic interaction. In the permanent stream drying provoked an increase in the shredder consumption rate. Thus, the expected more frequent intermittence in rivers under climate change may threaten the processing of organic matter.

Broadscale and fine‐scale variables predict the occurrence of a stream‐breading bufonid: Habitat use by the Arizona toad (Anaxyrus microscaphus)

AbstractArizona toad (Anaxyrus microscaphus) is a stream‐breeding bufonid of conservation concern in Arizona, New Mexico, Utah, and Nevada. We determined the occupancy and habitat use of the Arizona toad throughout its range. We surveyed 500‐m reaches along perennial and intermittent streams during the summers of 2021 and 2022 (n = 232) in Arizona. We recorded the presence of all toad life stages, focusing on larval stages. We related toad occupancy to broadscale environmental variables, including measures of bioclimate, habitat heterogeneity, solar radiation, and topography. We collected fine‐scale variables to summarize vegetation cover and substrate within plots (n = 53). We applied multiple occupancy models. Single‐species model results found low toad occupancy with high detection. Two principal component analyses (PCA) were run on broadscale and fine‐scale variables to reduce the number of variables included in the models. Toad occupancy was best predicted by top models with bioclimatic components; occupancy decreases with extremely hot temperatures and less precipitation. A logistic regression related toad presence to fine‐scale components with top models describing riparian complexity and algae. Arizona toads were selected for areas with foliar canopy cover, shallow water, algae cover, and pebble substrates. Arizona toad is an uncommon species and maintaining riparian forests of complex habitats with shallow and side‐channel flow will be important for toad conservation. Implications of less water cause riparian habitat to dry, which ultimately harms aquatic life.

Biological invasions in intermittent rivers and streams: current knowledge, and future frontiers

Intermittent rivers and ephemeral streams (IRES) have been overlooked in invasion science as the characteristic drying - wetting regimes are assumed to be a barrier to invasion processes. Flow contraction/cessation limits the persistence and success of water-dependent invasive alien species (IAS) in most IRES, while flash floods may restrict limnophilic and strictly terrestrial ones. However, IRES are subject to multiple anthropogenic stressors that could ultimately favour the arrival and spread of IAS and their mosaic of dynamic habitats may theoretically support both terrestrial and aquatic IAS. Successful IAS are characterised by adaptations, traits and life histories which facilitate rapid, opportunistic exploitation of habitats and resources. Here, the potential invasibility of IRES is discussed along with a summary of current knowledge gaps, examples and challenges across different continents. IAS in IRES should be considered a cause for concern but also an intriguing study system to understand the mechanics of biological invasions under global change.

Advancing low-flow quantile estimation: The role of areal scale factor (ASF) and annual flow–duration curves

Abstract Estimating the streamflow corresponding to a particular probability is of great importance in many hydrological studies, such as determining hydroelectric water potential, assessing water quality, and investigating sedimentation and drought. This paper aims to effectively estimate low-flow quantiles since hydrologic droughts motivate the study. The study illustrates a methodology, where droughts are characterized by the lower part of the flow–duration curve (FDC), and offers a perspective estimating low-flow quantiles related to the basin characteristics. Low-flow quantiles are derived both from traditional FDCs curves and median annual FDCs (AFDCs). As an innovation, the concept of areal scale factor, which represents a scaling ratio between the basin area and flow quantiles, was introduced. Unlike many other parametric approaches, this study models the streamflow quantiles depending on the basin characteristics instead of the parameters in the analytical equation of FDCs. The methodology was evaluated for the Western and Southwestern Anatolia regions in Turkey. The outcomes were compared for two types of FDCs in two regions. The approach gave similar results for both study regions. AFDCs provided a distinct advantage over traditional FDCs, especially for low-flow quantiles, due to the superiority of AFDCs in estimating streamflow quantiles of intermittent streams.

Navigating the drought: upstream migration of a small-sized Cypriniformes (Telestes muticellus) in response to drying in a partially intermittent mountain stream

River flow intermittence is a natural phenomenon intensified by human activities, such as water abstraction and the effects of climate change. A growing number of rivers are predicted to experience intermittent flows, which may impact the diversity and abundance of freshwater species. Dry riverbeds directly diminish the availability of habitats for freshwater organisms, and suitable environments can turn into ecological traps with reduced survival rates, posing a significant threat to population persistence. Even though fish movements can enable drought-affected populations to persist, little is known about individual fish movement between intermittent and perennial reaches. Here, we study the movement of individual PIT-tagged Italian riffle dace (Telestes muticellus) in an intermittent and perennial river reach before, during and after two severe drying events. A high proportion of fish from the intermittent reach survived the drying riverbed through directed upstream migration. This was manifested in fish living in the intermittent reach of the river displaying significantly higher linear ranges, and net travelled distances during the monitoring period than fish in the perennial reach, which remained resident with limited linear range and net distances travelled. This finding underscores the importance of conserving longitudinal river connectivity in the face of increased water scarcity and intermittent flow patterns.

The role of seedbanks and hyporheic refuges in supporting benthic invertebrate community resistance and resilience to dry phases

In intermittent streams, aquatic organisms use various strategies to face dry phases, but the relative contribution of these strategies to persist during dry phase remains unclear. Here, we investigated the in situ persistence of benthic invertebrates in the saturated hyporheic sediments and the “invertebrate seedbank” that persists in dry sediments across six Mediterranean intermittent streams. Taxonomic and functional responses within hyporheic and seedbank assemblages were compared with those in the benthic assemblages under connected flow conditions by combining field and mesocosms data. The dry phase duration in each stream was calculated to assess the responses of hyporheic and seedbank assemblages. Taxonomic composition and abundance-weighted traits related to resistance and resilience to face the dry phase in each assemblage type (benthic, hyporheic, seedbank) were determined. Taxonomic (richness and diversity) and functional (richness and dispersion) metrics were also calculated. We found that seedbank and hyporheic assemblages supported up to 16% and 40% of the benthic taxa, respectively. Only taxonomic and functional richness differed between assemblage types. Contrary to previous research, no clear relationship was established between diversity or the abundance of resistance traits and the duration of dry phase; however, a negative linear relationship was identified between the abundance of resilience traits and the duration of the dry phase. The increase in the frequency and duration of drying events due to climate change will reduce water availability in both saturated and unsaturated streambed sediments, compromising the persistence of aquatic biodiversity in intermittent streams.