Lowland Ecoregion Research Articles

Mayflies of the Bednja River, Croatia

Here we present the results of a mayfly study conducted on a hydromorphologically altered lowland river in Croatia, the Bednja River. Twenty-two mayfly species were recorded, Baetis fuscatus (Linnaeus, 1761) and Serratella ignita (Poda, 1761) being the most widespread and Paraleptophlebia submarginata (Stephens, 1836) and Cloeon dipterum (Linnaeus, 1761) the rarest species. A significant increase in mayfly species richness was observed along the river course. Nevertheless, cluster analysis showed that their assemblages were not grouped according to the study position along the Bednja River. The lowest species richness and diversity were recorded for the spring area. Surprisingly, the highest species richness was found at a site with moderate hydromorphological alterations, and the highest diversity at a site with severe hydromorphological alterations. This could be because the river is connected to numerous lateral streams and a variety of microhabitats are available. New distribution records in Croatia are presented for some rare species in Croatian freshwater habitats, such as Heptagenia longicauda (Stephens, 1836). Ephemera lineata Eaton, 1870 was recorded for the first time in the Pannonian lowland ecoregion (ER 11) in Croatia. Caenis cf. pseudorivulorum Keffermüller, 1960 has not yet been recorded in Croatian freshwater habitats, but since our identifications are based on juvenile specimens, its occurrence is still to be confirmed.

Papua at the Crossroads: A Plea for Systematic Conservation Planning in One of the Largest Remaining Areas of Tropical Rainforest

Land-use change has progressed rapidly throughout the Indonesian archipelago and is now intruding into western New Guinea (Tanah Papua), one of the world’s last wilderness areas with extensive tracts of pristine and highly diverse tropical rainforests. Tanah Papua has reached a crossroads between accelerating environmental degradation and sustainable development policies entailing landscape-scale conservation targets, pledged in the Manokwari Declaration. We assessed the representation of ecoregions and elevational zones within Tanah Papua’s protected area network to identify its shortcomings at broad spatial scales. Lowland ecoregions are less protected than mountainous regions, with half of the western and southern lowlands designated for land-use concessions. Under the direct threat from land-use change, the political motivation in Tanah Papua toward conservation- and culture-centered land management provides a window of opportunity for scientifically guided, proactive conservation planning that integrates sustainable development for the benefit of Indigenous communities.

Longitudinal dynamics of Odonata assemblages in an anthropogenically impacted lotic system

European lowland rivers are extensively impacted by hydromorphological pressures, and the relationship between individual benthic macroinvertebrate groups and these degradations are insufficiently investigated. Therefore, we studied distribution and ecological traits of Odonata inhabiting a lotic system in the Pannonian lowland ecoregion (ER 11) in Croatia affected by degraded water quality and hydromorphological stressors. The study encompassed multihabitat sampling of 20 longitudinally distributed sampling sites, selected for their representativeness of disturbances. Only five species were recorded withPlatycnemis pennipes(Pallas, 1771) andOnychogomphus forcipatus(Linnaeus, 1758) dominating. We found woody debris samples contained a disproportionately higher number of Odonata, especially Zygoptera, compared to all other sampled microhabitats. The downstream longitudinal increase in Odonata abundance was not followed by an expected increase in species richness. Only five (oxygen saturation, pH, ammonium, water temperature and total nitrogen) of the sixteen tested water quality parameters were significant variables in determining the variation of Odonata assemblages.Calopteryx virgo(Linnaeus, 1758) and juvenileGomphidaewere associated with sites of somewhat higher ammonium and total nitrogen concentrations while all other taxa showed a negative association to ammonium. Odonata abundances were affected by modification of the river channel where significant decrease in abundance was observed with increased modification. Our results suggest that even species with a broad ecological tolerance are sensitive to hydromorphological pressures and represent an important background for further research and conservation practices of lotic European Odonata.

Littoral mayfly assemblages in South-East European man-made lakes

Man-made freshwater habitats have been widely used to successfully modify the environment for human benefit, including purposes of irrigation, flood control or electricity generation. Over the past decade, our knowledge about the mayfly fauna and its ecology in South-East Europe has been growing, yet the data related to lentic assemblages remain very scarce. In this study, littoral mayfly assemblages were investigated at artificial and heavily modified lentic habitats in the Dinaric Western Balkan (n=21) and Pannonian Lowland (n=15) ecoregions. Mayfly nymphs were sampled during the summer months of 2016 or 2017. At each sampling site, ten samples were collected using a benthos hand net. A total of 21 mayfly species were recorded, though species richness per site was rather low (i.e., between zero and seven species). Cloeon dipterum (Linnaeus, 1761) was the most frequent species recorded, while Caenis horaria Linnaeus, 1758 was the most abundant. This study showed that the Croatian mayfly fauna is still growing, with the first record of Siphlonurus aestivalis Eaton, 1903 for the country. The assemblage structure was mainly dominated by lower reaches and lentic (potamal and littoral) elements and detritivores (gatherers/collectors and active filter feeders). Orthophosphates and chemical oxygen demand had the highest influence on mayfly assemblages, reflecting a higher level of pollution at sites in the Pannonian Lowland ecoregion, and consequently markedly lower mayfly abundances. As mayflies are widely used as bioindicators of freshwater ecosystems, detailed information about their assemblages in heavily modified and artificial habitats could contribute to future conservation activities of freshwater habitats and their communities. Additionally, these results could be applied in creating a monitoring system for artificial lakes according to the requirements of the European Water Framework Directive.

A new record of Kerivoula hardwickii (Horsefield, 1824) (Mammalia: Chiroptera: Vespertilionidae) after 23 years from a lowland rainforests of Sri Lanka

Distribution of Kerivoula hardwickii, Hardwicke's woolly bat, in Sri Lanka is restricted to the central highlands and to northeastern region of the country, and so far, only recorded from four distinct locations. In Sri Lanka, this species was last documented in the year 1994, and no subsequent surveys recorded this species in Sri Lanka, thus considered rare in Sri Lanka. In contrast, within its southern Asian biogeography, K. hardwickii is widely distributed, particularly in Southeastern Asia. In this study, a single male of K. hardwickii was observed in lowland rainforest ecoregion of Sri Lanka near Labugama-Kalatuwana Forest Reserve where the bat was roosting on a curled live banana frond. The bat was roosting 1.8 m above the ground. This was the first instance K. hardwickii was recorded in the lowland rainforests of Sri Lanka, which extends this species’ biogeography of Sri Lanka into the lowland wet zone. Thus, distribution range of K. hardwickii in Sri Lanka could be broader than historically documented. However, intensive surveys, particularly in lowland rainforest region, are required to validate the true distribution of this bat in Sri Lanka.

Influences of environmental factors on macroinvertebrate assemblages: differences between mountain and lowland ecoregions, Wei River, China.

Key environmental factors and the mechanisms of their influence on the physicochemical habitats and macroinvertebrate communities of streams may vary among ecoregions. We studied the differences in environmental (land use and physicochemical) factors and the mechanisms of their influence on macroinvertebrate assemblages between mountain and lowland ecoregions in central China. We applied generalized linear models to identify key environmental factors that influence macroinvertebrate metrics consisting of taxa richness, Ephemeroptera, Plecoptera, and Trichoptera (EPT) taxa, percentages of EPT and intolerant individuals, and the Shannon-Wiener diversity index. Environmental factors and macroinvertebrate metrics significantly differed between the ecoregions. Mountain streams had significantly lower nutrients and %silt, but had twice higher total taxa richness than lowland streams. Watershed land uses were key drivers that influenced the physical habitat in the mountain ecoregion and were the main drivers that influenced both physical and chemical conditions in the lowland ecoregion. Correspondingly, watershed scale land uses, as well as physical and chemical variables, explained more variance in macroinvertebrate metrics than local-scale land uses in both mountain and lowland ecoregions. The overall biological variation was explained better by watershed-scale than by reach-scale land uses, whereas the spatial scale over which land use and physicochemical variables influence streams varied across ecoregions. Our results suggest that better landscape planning should be adopted for watershed management to improve water quality and physical habitat, and thus the conservation and restoration of macroinvertebrate biodiversity.

Fire catalyzed rapid ecological change in lowland coniferous forests of the Pacific Northwest over the past 14,000 years.

Disturbance can catalyze rapid ecological change by causing widespread mortality and initiating successional pathways, and during times of climate change, disturbance may contribute to ecosystem state changes by initiating a new successional pathway. In the Pacific Northwest of North America (PNW), disturbance by wildfires strongly shapes the composition and structure of lowland forests, but understanding the role of fire over periods of climate change is challenging, because fire-return intervals are long (e.g., millennia) and the coniferous trees dominating these forests can live for many centuries. We developed stand-scale paleorecords of vegetation and fire that span nearly the past 14,000yr to study how fire was associated with state changes and rapid dynamics in forest vegetation at the stand scale (1-3ha). We studied forest history with sediment cores from small hollow sites in the Marckworth State Forest, located ~1km apart in the Tsuga heterophylla Zone in the Puget Lowland ecoregion of western Washington, USA. The median rate of change in pollen/spore assemblages was similar between sites (0.12 and 0.14% per year), but at both sites, rates of change increased significantly following fire events (ranging up to 1% per year, with a median of 0.28 and 0.38%, P<0.003). During times of low climate velocity, forest composition was resilient to fires, which initiated successional pathways leading back to the dominant vegetation type. In contrast, during times of high climate variability and velocity (e.g., the early Holocene) forests were not resilient to fires, which triggered large-scale state changes. These records provide clear evidence that disturbance, in the form of an individual fire event, can be an important catalyst for rapid state changes, accelerating vegetation shifts in response to large-scale climate change.

Croatian freshwater oligochaetes: species diversity, distribution and relationship to surrounding countries.

This paper presents a checklist of the freshwater oligochaetes of Croatia, including data related to the ecoregions, river basins and habitat types in which species were recorded. The checklist is based on literature data and new records from unpublished research conducted since 1975. A total of 71 freshwater oligochaete species were recorded at 345 sampling sites. The family Naididae was most species rich (31 species), followed by the family Tubificidae (27 species), Lumbriculidae (6 species) and Pristinidae (4 species). The families Haplotaxidae, Propappidae and Lumbricidae were least diverse, with only one species recorded for each. Approximately two-thirds of the oligochaete species occurred in both the Dinaric western Balkan and the Pannonian lowland ecoregions. Similar patterns in species richness were detected for the Black Sea and the Adriatic Sea basins. Species richness varied between habitat types, with rivers as the most speciose habitats. In comparison to adjacent countries, the Croatian oligochaete fauna was most similar to that of Bosnia and Herzegovina, Hungary and Austria.

Minimum sampling area for the monitoring of herb diversity in riparian zone of temperate rivers, China

AbstractOptimal sampling area for biodiversity monitoring is a classical scientific topic for the biodiversity research in view of the cost, human resources and ecological significance. However, how much sampling area is enough for biodiversity monitoring in riparian area, the ecotone among freshwater and terrestrial system? Whether the optimal sampling areas are different among ecoregions? To explore these scientific questions, the minimum sampling area of riparian herbs was studied in Taizi river, Liaoning province, China. The species‐area relationship was modeled using average species richness in the same area (2.25, 4.5, 6.75 and 9 m2) of 55 sites distributed along riparian zone of Taizi river water course. The power model S = aAb modeled best, and was selected to fit species‐area curves. The minimum sampling areas for total species and dominant families were calculated via the selected model and corresponding estimated species richness. Results showed that the minimum sampling areas (MSAs) for herbs diversity monitoring in whole basin, highland ecoregion, midland ecoregion and lowland ecoregion of Taizi river were 12.82, 12.06, 13.46 and 13.08 m2,respectively. The MSAs of dominant families Compositae species and Graminale species were similar to that of total species. The minimum sampling area of Taizi river riparian zone was similar to other temperate riparian grassland and wet grassland, larger than dry grassland and salt meadow. So we did not need consider ecoregion difference for temperate riparian herbs diversity monitoring in watershed scale.

Geographic distribution of the short-tailed river stingray (Potamotrygon brachyura): assessing habitat loss and fishing as threats to the world’s largest obligate freshwater elasmobranch

Freshwater elasmobranchs are threatened but little is known about them. Potamotrygon brachyura is the world’s largest obligate freshwater elasmobranch. This makes it popular among fishermen and suggests a susceptibility to anthropogenic threats. We collected records of P. brachyura (n=70) from media, fishermen and scientific sampling, to estimate its global geographic distribution (using both generalised additive and MaxLike models). Then, we estimated the species’ exposure to habitat modification and fishing pressure, by applying multinomial ordinal models with threat levels as response and the presence or absence of P. brachyura as an independent variable. Distance to coast, depth, water temperature range, salinity range and mean water temperature were the main determinants of the distribution in the Río de la Plata. This resulted in a narrow coastal distribution. In the Uruguay and Paraná River basins, the probability of occurrence was positively associated with flow accumulation, percentage of open water and submerged vegetation, and lowland ecoregions, and negatively to wetness index and altitude. This limited the distribution to large lowland rivers. Approximately 41% of the range of P. brachyura in the Río de la Plata was subject to high habitat modification. In the Uruguay and Paraná River basins, this percentage reached 7%; however, the overlap with high fishing pressure was 59%. For conservation purposes, P. brachyura may function as an umbrella species.

Surface Water and Groundwater Contributions to Streamflow in the James Bay Lowland, Canada

Climate and land-use changes are going to leave an indelible mark on the hydrology and globally significant peatlands of the Hudson Bay Lowlands (HBL), Canada. With forecasts for warmer and drier conditions over the next century, the relative contribution of water from surface and subsurface sources affecting both water quantity and quality will undoubtedly shift. Unfortunately, no empirical data exist for any streams or rivers of the HBL on the relative contributions of surface water and groundwater to streamflow, making assessment of future change difficult. Here we report the first data on sources of water to streams and rivers across a range of catchment sizes in the James Bay Lowland (JBL) ecoregion of the HBL. Solute chemistry was determined for a range of potential end members, end members were identified, and a chemical mixing model approach was used to determine the relative end-member contributions to streamflow across a range of catchment sizes (∼30–2000 km2). The relative contributions of bedrock-derived groundwater to streamflow increased with catchment area from <20 to >40% under dry conditions, and were ∼50% lower under wet conditions across all catchments. Runoff contributions from peatlands were relatively constant over space and time (53–67%), but the fraction of streamflow composed of rain and snowmelt varied dramatically between wet and dry periods, and among catchments. Given the importance of peatland-derived surface waters, future changes in precipitation and temperature could have significant implications for streamflow in the JBL, particularly during summer base-flow conditions. Moreover, the definition of reference catchments for baseline/impact monitoring must be carefully considered, given the potential for variation in hydrochemistry across physiographically similar catchments.

Response of three lotic assemblages to riparian and catchment‐scale land use: implications for designing catchment monitoring programmes

Summary1. Although many studies have focussed on the effects of catchment land use on lotic systems, the importance of broad (catchment) and fine (segment/reach) scale effects on stream assemblages remain poorly understood.2. Nine biological metrics for macrophytes (498 sites), benthic macroinvertebrates (491) and fish (478) of lowland and mountain streams in four ecoregions of France and Germany were related to catchment and riparian buffer land use using partial Redundancy Analysis and Boosted Regression Trees (BRTs).3. Lotic fauna was better correlated (mean max., r = 0.450) than flora (r = 0.277) to both scales of land use: the strongest correlations were noted for mountain streams. BRTs revealed strong non‐linear relationships between mountain assemblage metrics and land use. Correlations increased with increasing buffer lengths, suggesting the importance of near‐stream land use on biotic assemblages.4. Several metrics changed markedly between 10–20% (mountain ecoregions) and 40–45% (lowland) of arable land use, irrespective of the buffer size. At mountain sites with &gt;10% catchment arable land use, metric values differed between sites with &lt;30% and sites with &gt;30% forest in the near‐stream riparian area.5. These findings support the role of riparian land use in catchment management; however, differences between mountain and lowland ecoregions support the need for ecoregion‐specific management.

Additions to the Vascular Flora of Ontario, Canada, from the Sutton Ridges, Hudson Bay Lowland Ecoregion

Field studies in the Hudson Bay Lowland ecoregion of northern Ontario during 2010 resulted in the discovery of four native vascular plant species not previously confirmed from the province: Arctic Bellflower (Campanula uniflora; Campanulaceae), Lapland Diapensia (Diapensia lapponica; Diapensiaceae), Alpine Azalea (Kalmia procumbens; Ericaceae), and Alpine Brook Saxifrage (Saxifraga rivularis; Saxifragaceae). These four species are widespread arctic plants occurring in both North America and Eurasia and were found on the Sutton Ridges, a Precambrian bedrock inlier surrounded by the extensive wetlands of the Hudson Bay Lowland.

Reach- and Watershed-Scale Associations of Crayfish within an Area of Varying Agricultural Impact in West-Central Indiana

Abstract We studied the associations of crayfish with reach-scale instream habitat and water quality variables and watershed-scale variables of riparian and watershed land cover, runoff, impervious surfaces, and hydrologic soil type in west-central Indiana. Crayfish assemblage was measured by abundance, species richness, and diversity (Shannon's H) at 180 sites. The western portion of the study area, within the Interior River Lowland ecoregion, has been heavily impacted by agriculture, while the eastern portion, within the Interior Plateau ecoregion, is more heavily wooded and less impacted. The ability of variables at each spatial extent to predict crayfish assemblage was assessed using multiple linear regression analysis. Reach-scale models were better predictors of crayfish assemblage than watershed-scale models. A variety of habitat and water quality characteristics, principally instream cover, appeared as important predictors. Forested riparian and watershed land appeared as significant watershed-sca...

Physical and chemical limnology of a 61-lake transect across mainland Nunavut and southeastern Victoria Island, Central Canadian Arctic

We describe the physical and chemical properties of sixty-one tundra lakes, sampled in a latitudinal transect (65―71°N, 105―108°W) across mainland and island regions of Nunavut, central Canadian Arctic, and examine the influence of geology, geography, climate, and vegetation on lake water chemistry. This dataset complements earlier limnological surveys of the Canadian Arctic and provides valuable information for evaluating the vulnerability of tundra lakes to predicted climate change. Principal components analysis revealed a geographical clustering of lakes; pH, DIC, specific conductivity, and trace metal concentrations reflected major lithological differences between the mainland and Victoria Island. Clustering of mainland lakes by ecoregion was also detected. Lakes of the Queen Maud Gulf Lowland and Garry Lake Lowland ecoregions (north) differed from lakes of the Takijuq Lake Upland ecoregion (south) in depth, pH, and specihc conductivity as well as nutrient, DOC, and chlorophyll-a concentrations. Ionic composition of the northern mainland lakes also indicated that the influence of marine aerosols and/or leaching of residual marine salts from post-glacial marine deposits exposed by isostatic rebound. The northern mainland lakes were the most nutrient-rich and biologically productive of the three lake clusters and were characterized by median concentrations of total dissolved nitrogen (518 μg l ―1 ) and chlorophyll-a (1.6 μg l ―1 ) that were higher than previously reported for tundra lakes in the Canadian Arctic. These lakes were chemically similar to lakes of the Tuktoyaktuk Peninsula, in the western Canadian Arctic. Lakes of the southern mainland were dilute, acidic, and nutrient-poor, in accord with earlier limnological surveys in this ecoregion. Concentrations of nutrients, DOC, and chlorophyll-a in Victoria Island lakes fell in the middle of the ranges reported from other islands in the Canadian Arctic. Lithologic and edaphic factors strongly influenced the limnological properties of the tundra lakes surveyed and must be controlled for in order to fully evaluate the influence of future climate and vegetation change.

Potential impact of climate change on aquatic insects: A sensitivity analysis for European caddisflies (Trichoptera) based on distribution patterns and ecological preferences

We analysed the sensitivity of European Trichoptera (caddisfly) species to climate change impacts based on their distribution and ecological preferences, and compared the fraction of species potentially endangered by climate change between the European ecoregions. The study covers 23 European ecoregions as defined by Illies (1978). For 1134 Trichoptera species and subspecies, we coded 29 parameters describing biological and ecological preferences and distribution based on the evaluation of more than 1400 literature references. Five parameters served to describe the species’ sensitivity to climate change impacts: endemism, preference for springs, preference for cold water temperatures, short emergence period, and restricted ecological niches in terms of feeding types. Of the European Trichoptera species and subspecies, 47.9% are endemic, 23.1% have a strong preference for springs, 21.9% are cold stenothermic, 35.5% have a short emergence period, and 43.7% are feeding type specialists. The fraction of endemic species meeting at least one of the four other sensitivity criteria mentioned above is highest in the Iberic-Macaronesian Region (30.2% of all species), about 20% in several other south European ecoregions, and about 10% in high mountain ranges. In 15 out of 23 ecoregions (including all northern European and lowland ecoregions) the proportion is less than 3%.

Enhancing National Security and Energy Security in the Post-911 Era: Group Decision Support for Strategic Policy Analysis under Conditions of Conflict

Energy source diversity has become a fundamental principle of both US energy security and national security. The decision of whether or not to approve a new power plant facility in the US involves complex group decision and negotiation processes. These contentious, value-laden, and multi-faceted self organizing processes involve many decision makers (broad constituencies) with conflicting priorities and dynamic preferences, high decision stakes, limited technical information (both in terms of quality and quantity), and difficult tradeoffs. As population pressures and energy demands continue to mount, advances in conflict resolution can help to improve power plant siting processes as well as US energy security and national security. Specifically, this paper uses advances in the Graph Model for Conflict Resolution and its associated decision support system (DSS) GMCR II to analyze strategic aspects of a multi-party energy dispute involving the co-management of a shared air shed in the Fraser Lowland Eco-Region based on Sumas Energy 2 (SE2), a contentious power plant project proposed for the US side of the international border between the city of Abbotsford, British Columbia and town of Sumas, Washington. GMCR II provides strategic insights for enhancing energy security, national security, and environmental risk management in the United States.

The search for reference conditions for stream vegetation in northern Europe

Summary1. The European Water Framework Directive provides a framework for improving the ecological quality of stream ecosystems, with deviation from reference used as a measure of ecological status.2. Here we examine the possibility of using less impacted stream sites from Latvia, Lithuania and Poland to establish a Danish reference network for macrophyte assemblages, and as a guiding image for identification of possible references sites within Denmark. Both approaches were evaluated using historical Danish records.3. Four different macrophyte assemblages were identified for mid‐sized streams in the Central and Eastern Lowland ecoregions. Macrophyte assemblages could not be delineated using physical stream site characteristics; however a gradual change in assemblage composition was attributed to differences in alkalinity and human impact.4. Assemblages of contemporary vegetation in Denmark were quite similar to those found in Polish, Latvian and Lithuanian streams (26–35%). However, more importantly, from species‐based predictions we noted higher similarity, particularly with Latvian and Lithuanian streams, before intensive land use commenced in Denmark (c. 1900). These results show that stream sites from these three countries can be considered in a Danish reference network.5. Two of the four macrophyte assemblages comprised species such as Fontinalis antipyretica, Myriophyllum spicatum, Nuphar lutea, Potamogeton alpinus and P. perfoliatus that have a very scattered occurrence in the contemporary vegetation in Denmark. These groups were closely associated with the predictions from historic records, thereby lending support the conjecture that these assemblages could be part of the guiding image for the identification of potential reference sites within Denmark.

Influence of Environmental Variables on Stream Caddis Larvae in Three Slovenian Ecoregions: Alps, Dinaric Western Balkans and Pannonian Lowland

AbstractIdentification of the environmental variables that influence caddis larvae was performed on 504 samples collected at 94 sites within the three ecoregions of Slovenia; the Alps, the Dinaric western Balkans and the Pannonian lowland. Canonical Correspondence Analysis (CCA) was performed to find sig‐nificantly influential variables and compare their absolute and relative importance in structuring caddisfly assemblages in the different ecoregions. Altogether, 234 variables were considered. According to their type of influence on organisms, variables were classified as indirectly influential variables (e.g., altitude), and directly influential variables or ecological factors (e.g., temperature). Caddis larvae responses were characterized as log abundances of 132 taxa, of which 126 were identified at the species level. The absolute and relative influences of the same environmental variable were found to be different in the selected ecoregions. Of the ecological factors, temperature (maximum and range) was found to be the most important in both mountainous ecoregions (Alps and Dinaric western Balkans). In the Pannonian lowland ecoregion, periodicity was the most influential factor. Of the indirectly influential variables, those that were good predictors of caddis larvae assemblages in the mountainous ecoregions were relatively unimportant in the Pannonian lowland ecoregion. Differences among ecoregions were also found in the cumulative explained variation in the caddisfly distribution, which was the highest in the Alps and the lowest in the Pannonian lowland. (© 2007 WILEY‐VCH Verlag GmbH &amp; Co. KGaA, Weinheim)

Additions to the Flora of the Continental Northwest Territories from the Great Slave Lake Area

Eleven species are reported as new to the flora of the continental Northwest Territories. The new native species include Artemesia dracunculus, Chenopodium leptophyllum, Eleocharis erythropoda, Panicum capillare, Schoenoplectus pungens and Symphyotrichum lanceolatum subsp. hesperium var. hesperium. New alien species reported include Achillea ptarmica, Chaenorhinum minus, Galium aparine, Malva neglecta and Silene cserei. Sonchus arvensis, previously reported, is based on material referable to a subsp. uliginosus. Forms new to the flora include Achillea millefolium f. rosea and Actaea rubra f. neglecta. Locations, habitats and distinctive features are provided for the additional taxa. The Hay River lowland ecoregion is a floristically rich area that deserves more botanical exploration. Erratum included.