Academic literature on the topic 'Invasive willows'

The vines Echinocystis lobata and Parthenocissus quinquefolia are spreading over the natural vegetation in riparian zones, which may significantly affect riparian vegetation properties and the quality of litter for aquatic organisms. We examined leaf morphological, biochemical and optical traits of these invasive alien species, each paired with its host, the willows Salix caprea and S. fragilis, respectively. The vines altered the host radiation environment and the amount of photosynthetic pigments. Both vines had significantly higher specific leaf area and lower leaf tissue density compared to the willows, even though the leaves of P. quinquefolia were significantly thicker. Leaf optical properties varied significantly between vines and willows in some spectral regions. Compared to the willows, the vines reflected less light as UV, and more as green, and transmitted more light as green, yellow and red. The overgrowth of the willows with vines affected the reflectance of the willow leaves. Redundancy analysis of the relationships between leaf biochemical traits and reflectance spectra showed that chlorophyll a, anthocyanins, and UVB- and UVA-absorbing substances explained 45% of the reflectance spectra variability, while analysis with morphological traits revealed that specific leaf area, leaf thickness and upper cuticle thickness explained 43%. For leaf transmittance, UVB- and UVA-absorbing substances, carotenoids and anthocyanins explained 53% of the transmittance spectra variability, while analysis with morphological traits revealed that specific leaf area explained 51%. These data show that invasive alien vines can be discerned from each other and their hosts by their spectral signatures. In addition, the differences in the leaf functional traits between the vines and their hosts indicate significant differences in the quality of the plant litter entering the river.

Many invasive plant species are sparsely distributed across large areas Management of these species is often undertaken using a search and destroy approach where people search the landscape and treat (destroy) any individuals found However detection is imperfect and so these searches need to be undertaken on multiple occasions Given limited resources an explicit objective is to optimize efforts by targeting those areas for follow up visits that have the highest predicted abundance In order to simultaneously estimate both abundances and detection rates from data on search and destroy efforts it is necessary to have a good model of the detection process itself In a case study of invasive willow control across 120 km2 in alpine Australia intensively monitored sample plots were used to characterise how detection rates depend on perceived abundance for three groups of willow control contractors Bayesian models were used to fit an exponential detection function where the detection rate varied with plant size between contractors with the total number of willows treated and on features of the contractors movements It was found that detection rates decreased with increasing abundance but areas with high abundance were subject to greater search effort These models were combined with GPS tracking data representing 6 weeks of search and destroy missions to predict the remaining abundance of willows across the landscape and hence areas that are priorities for follow up control were identified

AbstractSalicaceae are typical invaders of riparian ecosystems throughout the world and they have the potential to change much of the invaded habitats. Along Patagonian streams, riparian softwood forests composed of non-native Salicaceae are increasing in abundance, area and tree species diversity. Especially in the last decades, dense floodplain forests dominated by invasive willows and poplars and additionally Russian olive and tamarisk spread almost explosively e.g. along the Río Negro in northern Patagonia. This study focuses on the identification of ecological niches and niche overlaps of the native and invasive woody species in order to assess the impact on the native Salix humboldtiana Willd. Data on species (presence/ absence) and explanatory variables were gathered in the field using a grid-based, stratified-randomized sampling design. Different environmental variables were then related to species occurrence in different life stages (adult, juvenile, seedling) using habitat distribution models. In the final models, flood duration, the amount of gravel and the location (upper or middle river valley) were included to describe the probability of occurrence of native and invasive taxa. For all life stages, a strong niche overlap could be observed for S. humboldtiana and the invasive taxa with no remaining exclusive habitats indicating a potential threat to the native willow. The study contributes to a better understanding of Salicaceae invasion and its consequences for riparian ecosystems.

The giant willow aphid (Tuberolachnus salignus) is a large stem-feeding insect which forms dense colonies on infested plants. Since T. salignus is a new invasive species in New Zealand, we have a poor understanding of the plant chemical responses to aphid infestation. This study aimed to characterize the volatile organic compounds (VOCs) emissions of fifteen different willow species and hybrids growing in New Zealand, and to evaluate changes in response to T. salignus attack in a field trial. Volatiles were collected using a headspace sampling technique and analysed using gas chromatography-mass spectrometry (GC-MS). We found high variability in the volatile profiles of different species and hybrids, with (Z)-3-hexenyl acetate and (E)-β-ocimene being the only common components to all blends. Taxonomically related plants showed an overlapping pattern of VOC emission, and there seemed to be a clear separation between shrub and tree willows. Responses to aphid infestation were variable, with only four species/hybrids showing changes in their total VOC emission, or that of at least one class of VOCs. A weak positive correlation between aphid population estimates and VOC emissions suggests that responses are species-specific and not infestation-dependent. These results reveal useful information about the interaction between T. salignus and its potential host plants for biological control and pest management purposes.

The Tijuana River Valley is the first natural habitat in California to be substantially invaded by the Kuroshio Shot Hole Borer (KSHB,Euwallaceasp.), an ambrosia beetle native to Southeast Asia. This paper documents the distribution of the KSHB in the riparian vegetation in the valley and assesses the damage done to the vegetation as of early 2016, approximately six months after the beetle was first observed in the valley. I divided the riparian habitats into 29 survey units so that the vegetation within each unit was relatively homogenous in terms of plant species composition, age and density. From a random point within each unit, I examined approximately 60 individuals of the dominant plant species for evidence of KSHB infestation and evidence of major damage such as limb breakage. In the 22 forested units,I examined the dominant arroyo and black willows (Salix lasiolepisBenth. andS. gooddingiiC.R. Ball), and in the seven scrub units, I examined mule fat (Baccharis salicifolia(Ruiz & Pav.) Pers.). Evidence of KSHB infestation was found in 25 of the 29 units. In the forest units, infestation rates ranged from 0 to 100% and were high (>60%) in 16 of the units. In the scrub units, infestation rates ranged from 0 to 33%. Infestation rates were significantly correlated with the wetness of a unit; wetter units had higher infestation rates. Evidence of major physical damage was found in 24 units, and dense stands of willows were reduced to broken trunks in several areas. Overall, I estimated that more than 280,000 (70%) of the willows in the valley were infested, and more than 140,000 had suffered major limb damage. In addition, I recorded evidence of KSHB infestation in the other common plant species in the valley; of the 23 species examined, 14 showed evidence of beetle attack. The four species with the highest rates of infestation were native trees in the Salicaceae family. The three species considered to be the worst invasive plants in the valley,Ricinus communisL., Tamarix ramosissimaLedeb. andArundo donaxL., had low rates of infestation. Several findings from this study have significance for resource managers: (1) the KSHB attack caused extensive mortality of trees soon after being first discovered so, if managers are to control the spread of the beetle, they will need to develop an effective early detection and rapid response program; (2) infestation rates were highest in units that were wet, so resource managers trying to detect the beetle in other areas should thoroughly search trees near water, particularly nutrient-enriched water; (3) the infestation appears to be a novel form of disturbance, and the affected forests may need special management actions in order to recover; and (4) the infestation has altered the structure of the forest canopy, and this is likely to promote the growth of invasive plant species that were relatively inconspicuous in the forests prior to the beetle attack but will now need more attention.

The Kuroshio Shot Hole Borer (KSHB, Euwallacea kuroshio) and the Polyphagous Shot Hole Borer (E. whitfordiodendrus; Coleoptera: Curculionidae: Scolytinae) have recently invaded southern California and are attacking live trees in commercial agriculture groves, urban parks and native riparian forests. Among native forests the worst impacts observed to date have been in the Tijuana River Valley in south San Diego County, where approximately 30% of the native willows (Salix spp.), or 120,000 trees, have died as a result of a KSHB infestation. This paper examines wood densities, wood moisture contents, KSHB infestation rates, and KSHB-induced mortality rates in two willow species (Salix lasiolepis and S. gooddingii) at sites near and far from sewage input. Comparisons were made on two spatial scales: broadly among sites within San Diego County; and locally among sites within the Tijuana River Valley. The results showed that, on average, willow trees growing closest to sewage pollution had significantly lower wood density, higher wood moisture content, higher KSHB infestation rates, and higher KSHB-induced willow mortality rates than those growing farther away. We present the Enriched Tree Hypothesis to explain the link between sewage pollution and KSHB impacts; it is as follows: (A) Riparian trees subject to nutrient enrichment from frequent sewage pollution grow quickly, and their fast growth results in wood of low density and high moisture content. If attacked by the KSHB, the trunks and branches of these nutrient-enriched trees provide an environment conducive to the fast growth of the symbiotic fungi upon which the KSHB feeds. With an abundant food supply, the KSHB population increases rapidly and the trees are heavily damaged by thousands of KSHB galleries in their trunks and branches. (B) Riparian trees not subject to frequent sewage pollution grow more slowly and have denser, drier wood. Conditions in their trunks and branches are not conducive to the fast growth of the KSHB’s symbiotic fungi. The KSHB generally ignores, or has low abundances in, these slow-growing trees. This new hypothesis explains current patterns of KSHB impact in San Diego County and focuses attention on the important roles of the environment and preexisting conditions of trees in determining the extent of KSHB impact. It highlights the Tijuana River Valley as an unusual site due to high sewage inputs and predicts that the high KSHB-induced willow mortality seen there should not occur in other natural riparian habitats in southern California. Most importantly, by identifying sewage pollution (or nutrient enrichment) as a major risk factor for KSHB impacts, the hypothesis ratchets down the KSHB-threat level for most riparian sites in southern California and directs attention to other nutrient-enriched sites as those most at risk.

Knowledge of the reproductive and dispersal dynamics of invasive species is central to designing control strategies that minimise local population growth, limit range expansion and reduce the likelihood of reinfestation. Molecular ecological methods in plant population studies has allowed a greater ability to quantify ecological processes such as mating patterns and dispersal which are hard to measure with traditional ecological approaches. Such approaches would be beneficial in the management of environmental weeds to provide information on reproductive and dispersal dynamics that can be used in the development of more effective scale-appropriate management strategies. Willows are aggressive exotic components of many river systems in south-eastern Australia. Current control efforts for the most highly invasive willow species, Salix cinerea, are extensive, costly and not always successful due to rapid post-removal reinfestation. A survey of populations in the Ovens River catchment of south-eastern Australia was undertaken to determine the reproductive ecology, catchment scale variance in population fecundity and dispersal dynamics within and between populations of S. cinerea. The species was found to be predominately insect pollinated but can exhibit wind pollination. Mean seed production was found to be higher than 300,000 seeds per tree across sites and years and is driven by tree size and flowering effort. Predictions of seed production at sites across the study catchment based on population and tree size and flowering effort showed that removing the top 20% of seed producing sites would result in a reduction in catchment seed set of over 50%. This high reproductive output combined with high initial germination rates, above 95%, gives the species the potential to reinfest cleared areas and expand its range. Microsatellite-based paternity analysis was used at four sites to ascertain the relative frequency of within versus between population mating events and identify the variation of male reproductive fitness. Observed patterns of within-site mating dynamics have highlighted a highly skewed male fitness distribution with a small number of fathers being responsible for a large proportion of successful fertilisation events. Genetic profiling of populations in surrounding rivers allowed identification of the most likely pollen and seed sources to give an estimate of the scale of dispersal. Results show that 60% of pollen and 50% of seed is moving more than 15 kilometres and a small amount travelling over 30 kilometres. These results suggest control of propagule pressure will be important for preventing future invasion. This may be attained by clearing high density sites that have the greatest reproductive output; subsequently targeting large trees at sparse and remote sites will have the greatest success in reducing propagule pressure. Reproductive dynamics were found to be heavily reliant on inter-site pollen and seed movement. Extensive pollen and seed dispersal was found among sites and among rivers across the catchment. These results suggest that future control efforts should emphasise removal of large high fitness individuals and populations with high reproductive output as well as spatially coordinating control activities across sites so as to account for inter-site reproductive dynamics.

This thesis explores the hydrological factors that may contribute to the observed distribution patterns of invasive willows (Salix) and native trees (Eucalyptus camaldulensis, E. largiflorens and Acacia stenophylla) along the Lower River Murray (LRM) in southern Australia. An initial survey, establishing the diversity and flowering biology of Salix taxa was carried out to ascertain the extent of invasion, and the likelihood of hybridisation, which may accelerate invasion. S. babylonica, S. fragilis, S. × chrysochoma and S. × rubens occur in the study region, each represented by a single gender. None were present on floodplains, but the most dominant taxon, S. babylonica, occurred along the entire length of the main channel. No seed or seedlings were observed; hence reproduction is likely to be asexual. More detailed survey work was then carried out to characterise the distribution patterns of the dominant S. babylonica and co-occurring natives (Eucalyptus camaldulensis, E. largiflorens and Acacia stenophylla) along a hydrologic gradient produced by the extensive weir system in the LRM. In weir pools, variation in daily water levels of weir pools is low (± 0.1 m) immediately upstream of the weir, but higher immediately downstream (0.2-1.0 m daily). The distribution of natives was uniform across weir pools, while S. babylonica was more abundant above weir structures, suggesting low tolerance to variable water regimes. Hypotheses relating to the observed distribution patterns were then tested experimentally on juveniles of the S. babylonica, E. camaldulensis and A. stenophylla. The experiment was carried out in outdoor ponds using an orthogonal design, with four elevations in relation to water level (-25 cm, 0 cm +25 cm, + 50 cm) under each of three water regimes. Experimental water regimes manipulated the magnitude of daily water level changes (static, 0 m dayˉ¹ ; moderate, ± 0.05 - 0.15 m dayˉ¹; high, ± 0.2 -0.5 m dayˉ¹) to mimic typical hydrological conditions across weir pools in the LRM. Final biomass and mean relative growth rates (S. babylonica, 0.0403 ± 0.002 g mˉ²dayˉ¹ A. stenophylla, 0.0249 ± 0.0017 g m ˉ² dayˉ¹; E. camaldulensis, 0.0204 ± 0.0016g mˉ² dayˉ¹) of all 3 species were unaffected by water regimes (i.e. water fluctuations), but were affected by elevation. Survival of both S. babylonica and A. stenophylla was lowest at low elevations where inundation was high. At higher elevations (+25 cm, +50 cm) the RGR of S. babylonica juveniles was much higher than the native juveniles. To test if the persistence of adults of each species along hydrologic gradients were associated with differing tolerances to water deficits and water use characteristics, S. babylonica and native species were examined under typical hydrological conditions in the field and during an unusual drawdown. S. babylonica occurring at the lowest elevations on riverbanks, had the least negative predawn shoot water potential (ψpredawn), followed by the natives, which were at higher elevations. A. stenophylla had the lowest stable carbon isotope ratio (δ¹³C) values (by 1.7 ‰) on the riverbank; suggesting more profligate water use than S. babylonica and E. camaldulensis. However, all riverbank trees had significantly less negative ψpredawn and lower δ¹³C than native trees on floodplains, consistent with higher water availability on riverbanks. The position and stable oxygen isotope ratio (δ¹⁸O) values were consistent with riverbank S. babylonica sourcing their water directly from the river or from shallow soil-water sources (<0.25 m). In floodplain habitats, depth to water was > 2.5 m, and groundwater was 5 times more saline (4.97 ± 0.88 dS mˉ¹) than river-water. Native trees with deep roots, the ability to lower water potentials and alter water use efficiencies may be at an advantage in this habitat relative to S. babylonica. Extreme low flows in the LRM, over a 6-month period, provided an opportunity to assess how S. babylonica and E. camaldulensis responded to a river-water drawdown. During the drawdown, river-water levels fell at a rate of ~2 – 2.5 mm dayˉ¹ and dropped to a minimum of 0.42 m below the designated pool level. S. babylonica and E. camaldulensis maintained high ψpredawn across the drawdown period, most likely because riverbank soil water availability was not limited; as depth to water table only decreased marginally (≤0.15 m) and soil water content and soil water potential were high (<1.1 MPa). However, an above average rainfall in February 2003 significantly increased soil water potential in the upper 0.25 m of the riverbank, which correlated with a significant increase in ψpredawn in E. camaldulensis, suggesting they were able to use shallow, precipitation derived soil-water sources whereas S. babylonica were not. Also under hot, dry conditions, S. babylonica had higher transpiration rates and lower instantaneous water use efficiencies than co-occurring E. camaldulensis. This suggests that S. babylonica may consume larger volumes of water per unit leaf area than natives, if access to water is maintained.
Thesis (Ph.D.) - University of Adelaide, School of Earth and Environmental Sciences, 2010

<em>Abstract</em>.—Formulating effective restoration goals and strategies for riparian ecosystems requires knowledge of the sources of variability at local and broad landscape scales. We examine sources and influences of natural and human-induced variability in riparian ecosystems and discuss their implications for restoration actions and recovery. We recommend that the development of restoration strategies should apply landscape perspectives that emphasize the connectivity of riparian systems to associated terrestrial and aquatic ecosystems. Particularly important are processes that involve the exchange of surface–subsurface waters, sediments, organic matter, and organisms between riparian and other ecosystems. Furthermore, the development of strategies should be based on understanding how past natural disturbances and human alterations and uses alter the connectivity and processes of riverine habitats throughout a drainage. Historical or retrospective information increases our understanding of how riparian and aquatic ecosystems function and provides insights on how to conserve and restore these resources. Although many restoration initiatives strive to repair ecosystem damage caused by humans, more recent views maintain that restoration efforts should facilitate the self-sustaining occurrence of natural processes and linkages among riparian, terrestrial, and aquatic ecosystems. Three general restoration strategies are presented: conservation, passive restoration (riparian reserves and buffer zones), and active restoration (flow and floodplain manipulations, restoring cottonwood/willow communities, and reducing invasive and exotic plants). Regardless of the strategy employed, restoration objectives should recognize that different portions of a riparian system can exhibit an array of recovery patterns as well as failure scenarios. Thus, objectives and strategies should enable us to evaluate the success of restoration activities as well as possibilities for continued degradation.

An aneurysm is a localised persistent dilation of the blood vessel wall. Aneurysm formation is hypothesised to be a consequence of haemodynamically generated forces working on the arterial wall leading to degeneration of the media layer (1). This focal degeneration typically occurs at curved arterial segments and at bifurcation points around the circle of Willis. Intracranial aneurysms are traditionally classified by aetiology and morphology. The majority are idiopathic and saccular. It is estimated that 1.5–6% of the general population have or will develop an intracranial aneurysm, predominantly occurring in women, most of them being asymptomatic (1). If left undetected these aneurysms may rupture with a 30 day mortality rate of 45% (1). There are two treatment options surgical clipping or endovascular coiling. Both of these techniques exclude the aneurysm from the normal circulation. Endovascular coiling is preferred due to its minimally invasive nature. Numerous studies have been done so far based on idealized glass models and using FVM, FEA methods, but very little testing has been carried out on devices using realistic silicone models. This is mainly because of the complexity of the cerebral vasculature. Silicone replicas of both realistic and idealised models were manufactured based on CT scans and anatomical dimensions obtained from literature, respectively (2).

Cerebral aneurysms generally occur at arterial bifurcations and arterial curves in or near the circle of Willis. For the treatment of this disorder, stent placement has been valued as a minimal invasive therapy. The effect of stents on flow reduction in cerebral aneurysms has been examined in several computed fluid dynamics (CFD) studies, suggesting that the stent position or the strut shape may affect flow reduction. However, the position of the stent with the best effect on flow reduction is still unknown because of the flow complexity. Three-dimensional visualization may help to easily specify the inflow zone from the parent artery to the aneurysm and to find the relationship between the effective strut position and the flow pattern. However, confirmation of the ability of 3D visualization to determine the effective position of a stent has not been achieved. In this study, we simulated blood flow with several aneurysm geometries to confirm the effect of 3D visualization on determination of optimal stent position. First, flow simulation using real aneurysm geometries without a stent was performed as a “pre-stenting situation.” Meshes were generated using a commercial code (Gambit 2.3, Fluent Inc., NH). CFD was carried out using a commercial code (Fluent 6.3, Fluent Inc., NH) based on steady flow. The streamlines around an aneurysm were visualized using a 3D visualization system (EnSight Gold 8.2, Comuputational Engineering Inc., NC) in Realization Workspace (RWS) to visualize the inflow zone. Secondly, a rectangular solid as a strut model was set in the inflow zone using computer-aided design (CAD) techniques. CFD was then performed as a “post-stenting situation” under the same conditions as the pre-stenting situation using the same mesh generator and CFD code. Three-dimensional visualization showed an inflow zone in the aneurysm. A bundle of flow streamlines hit the wall of the neck of the aneurysm and entered it. The inflow zone was a narrow local part in contrast to the outflow. After setting a strut, a change of flow pattern could be observed. The flow speed and the wall shear stress (WSS) were both reduced. When the strut position was moved away from the original position, the flow speed and the WSS were not reduced. These results may suggest that 3D visualization can provide information useful for strut positioning to realize effective reduction of flow into an aneurysm, especially a side wall aneurysm.

Highly imperiled Oregon white oak ecosystems are a regional conservation priority of numerous organizations, including Oregon Metro, a regional government serving over one million people in the Portland area. Previously dominant systems in the Pacific Northwest, upland prairie and oak woodlands are now experiencing significant threat, with only 2% remaining in the Willamette Valley in small fragments (Hulse et al. 2002). These fragments are of high conservation value because of the rich biodiversity they support, including rare and endemic species, such as Delphinium leucophaeum (Oregon Department of Agriculture, 2020). Since 2010, Metro scientists and volunteers have collected phenology data on approximately 140 species of forbs and graminoids in regional oak prairie and woodlands. Phenology is the study of life-stage events in plants and animals, such as budbreak and senescence in flowering plants, and widely acknowledged as a sensitive indicator of environmental change (Parmesan 2007). Indeed, shifts in plant phenology have been observed over the last few decades as a result of climate change (Parmesan 2006). In oak systems, these changes have profound implications for plant community composition and diversity, as well as trophic interactions and general ecosystem function (Willis 2008). While the original intent of Metro’s phenology data-collection was to track long-term phenology trends, limitations in data collection methods have made such analysis difficult. Rather, these data are currently used to inform seasonal management decisions on Metro properties, such as when to collect seed for propagation and when to spray herbicide to control invasive species. Metro is now interested in fine-tuning their data-collection methods to better capture long-term phenology trends to guide future conservation strategies. Addressing the regional and global conservation issues of our time will require unprecedented collaboration. Phenology data collected on Metro properties is not only an important asset for Metro’s conservation plan, but holds potential to support broader research on a larger scale. As a leader in urban conservation, Metro is poised to make a meaningful scientific contribution by sharing phenology data with regional and national organizations. Data-sharing will benefit the common goal of conservation and create avenues for collaboration with other scientists and conservation practitioners (Rosemartin 2013). In order to support Metro’s ongoing conservation efforts in Oregon white oak systems, I have implemented a three-part master’s project. Part one of the project examines Metro’s previously collected phenology data, providing descriptive statistics and assessing the strengths and weaknesses of the methods by which the data were collected. Part two makes recommendations for improving future phenology data-collection methods, and includes recommendations for datasharing with regional and national organizations. Part three is a collection of scientific vouchers documenting key plant species in varying phases of phenology for Metro’s teaching herbarium. The purpose of these vouchers is to provide a visual tool for Metro staff and volunteers who rely on plant identification to carry out aspects of their job in plant conservation. Each component of this project addresses specific aspects of Metro’s conservation program, from day-to-day management concerns to long-term scientific inquiry.

Climate and hydrology are major drivers of ecosystems. They dramatically shape ecosystem structure and function, particularly in arid and semi-arid ecosystems. Understanding changes in climate, groundwater, and water quality and quantity is central to assessing the condition of park biota and key cultural resources. The Sonoran Desert Network collects data on climate, groundwater, and surface water at 11 National Park Service units in south-ern Arizona and New Mexico. This report provides an integrated look at climate, groundwater, and springs conditions at Saguaro National Park (NP) during water year 2019 (October 2018–September 2019). Annual rainfall in the Rincon Mountain District was 27.36" (69.49 cm) at the Mica Mountain RAWS station and 12.89" (32.74 cm) at the Desert Research Learning Center Davis station. February was the wettest month, accounting for nearly one-quarter of the annual rainfall at both stations. Each station recorded extreme precipitation events (>1") on three days. Mean monthly maximum and minimum air temperatures were 25.6°F (-3.6°C) and 78.1°F (25.6°C), respectively, at the Mica Mountain station, and 37.7°F (3.2°C) and 102.3°F (39.1°C), respectively, at the Desert Research Learning Center station. Overall temperatures in WY2019 were cooler than the mean for the entire record. The reconnaissance drought index for the Mica Mountain station indicated wetter conditions than average in WY2019. Both of the park’s NOAA COOP stations (one in each district) had large data gaps, partially due to the 35-day federal government shutdown in December and January. For this reason, climate conditions for the Tucson Mountain District are not reported. The mean groundwater level at well WSW-1 in WY2019 was higher than the mean for WY2018. The water level has generally been increasing since 2005, reflecting the continued aquifer recovery since the Central Avra Valley Storage and Recovery Project came online, recharging Central Arizona Project water. Water levels at the Red Hills well generally de-clined starting in fall WY2019, continuing through spring. Monsoon storms led to rapid water level increases. Peak water level occurred on September 18. The Madrona Pack Base well water level in WY2019 remained above 10 feet (3.05 m) below measuring point (bmp) in the fall and winter, followed by a steep decline starting in May and continuing until the end of September, when the water level rebounded following a three-day rain event. The high-est water level was recorded on February 15. Median water levels in the wells in the middle reach of Rincon Creek in WY2019 were higher than the medians for WY2018 (+0.18–0.68 ft/0.05–0.21 m), but still generally lower than 6.6 feet (2 m) bgs, the mean depth-to-water required to sustain juvenile cottonwood and willow trees. RC-7 was dry in June–September, and RC-4 was dry in only September. RC-5, RC-6 and Well 633106 did not go dry, and varied approximately 3–4 feet (1 m). Eleven springs were monitored in the Rincon Mountain District in WY2019. Most springs had relatively few indications of anthropogenic or natural disturbance. Anthropogenic disturbance included spring boxes or other modifications to flow. Examples of natural disturbance included game trails and scat. In addition, several sites exhibited slight disturbance from fires (e.g., burned woody debris and adjacent fire-scarred trees) and evidence of high-flow events. Crews observed 1–7 taxa of facultative/obligate wetland plants and 0–3 invasive non-native species at each spring. Across the springs, crews observed four non-native plant species: rose natal grass (Melinis repens), Kentucky bluegrass (Poa pratensis), crimson fountaingrass (Cenchrus setaceus), and red brome (Bromus rubens). Baseline data on water quality and chemistry were collected at all springs. It is likely that that all springs had surface water for at least some part of WY2019. However, temperature sensors to estimate surface water persistence failed...