Migratory Waterfowl Research Articles

Exceeding expectations increases satisfaction among Louisiana waterfowl hunters

AbstractLouisiana surveys waterfowl hunters every 5 years to assess hunter effort, harvest success, demographics, and preferences for proposed regulations and management practices. The 2020 Survey of Louisiana Waterfowl Hunters addressed hunter satisfaction patterns, hunter perceptions on waterfowl migration, associations of field experiences to satisfaction, associations among distribution waves, the efficacy of sample coverage by an email survey, and allowed comparison with hunter satisfaction with surveys in 2005, 2010, and 2015. We distributed a 31‐question survey by email to 73,554 Louisiana waterfowl hunters following the 2019–2020 season. We received 13,483 total responses, of which 8,218 were usable (licensed respondents actively hunting waterfowl during the 2019–2020 season), resulting in a qualified response rate of 12.0%. We compared qualified respondents to the overall population of Harvest Information Program registrants (169,891) and found no significant differences for age class, geographic distribution, and license type. Our results indicated that surveys should be distributed in 3 waves, as the number of days hunted would be overestimated by 7% (mean of 15 days [95% confidence interval = 14.7–15.7] compared to a mean of 14 days [95% confidence interval = 13.7–14.4]) by a single survey. Hunters' satisfaction was independent of which geographic zone they hunted, whether they were members of conservation organizations, or how many waterfowl were seen. Our results also indicated that the probability of greater hunter satisfaction was increased by 98% as the number of waterfowl harvested surpassed 57, by 68% for respondents reporting that their actual harvest exceeded expected harvest by at least one bird, and by 61% for respondents reporting that their actual days hunted exceeded expected days hunted by at least one day.

Molecular Screening and Characterization of Enteric Protozoan Parasites and Microsporidia in Wild Ducks from Portugal.

Enteric parasites pose significant threats to both human and veterinary health, ranking among the top causes of mortality worldwide. Wild migratory waterfowl, such as ducks, may serve as hosts and vectors for these parasites, facilitating their transmission across ecosystems. This study conducted a molecular screening of enteric parasites in three species of wild ducks of the genus Anas (A. acuta, A. platyrhynchos and A. crecca) from Portugal, targeting Blastocystis sp., Balantioides coli, Cryptosporidium spp., Encephalitozoon spp., and Enterocytozoon bieneusi. Fecal samples from 71 ducks were analyzed using PCR and sequencing techniques. The results revealed a 2.82% occurrence of Blastocystis sp. subtype 7 and Cryptosporidium baileyi, marking the first molecular detection of these pathogens in wild ducks in Portugal. While previous studies have documented these parasites in Anas spp. in other regions, this study contributes novel data specific to the Portuguese context. No evidence of Balantioides coli, Encephalitozoon spp. or Enterocytozoon bieneusi was found. These findings highlight the potential role of migratory ducks as vectors for zoonotic protozoa, emphasizing the need for enhanced surveillance of avian populations to mitigate cross-species transmission risks. Further research is warranted to understand the global public health implications associated with migratory waterfowl.

Metagenomic analysis of the gut microbiota of hooded cranes (Grus monacha) on the Izumi plain in Japan.

Recent advances in DNA sequencing technology have dramatically improved our understanding of the gut microbiota of various animal species. However, research on the gut microbiota of birds lags behind that of many other vertebrates, and information about the gut microbiota of wild birds such as migratory waterfowl is particularly lacking. Because the ecology of migratory waterfowl (e.g., lifestyle, diet, physiological characteristics) differs from that of other birds, the gut microbiota of migratory waterfowl likely also differs, but much is still unknown. The hooded crane (Grus monacha) is an important representative migratory waterbird species and is listed as endangered on the International Union for Conservation of Nature and Natural Resources Red List of Threatened Species. In this study, we analyzed the bacterial and viral microbiota in the gut of hooded cranes by using deep sequencing data from fecal samples of hooded cranes that winter on the Izumi plain in Japan, and found that Cetobacterium, Clupeiformes, and Pbunavirus were clearly present in the fecal samples of hooded cranes. These findings advance our understanding of the ecology of hooded cranes.

Broad geographic variation in age- and sex-dependent origin of harvested eurasian wigeon (Mareca penelope) revealed by stable-hydrogen (δ2H) isotope analyses of feathers

Migratory waterfowl are a harvested resource shared among multiple European countries, exposing them to potential overexploitation. Management of take is challenging since the life cycle of migratory waterfowl consists of several stages distributed among several locations, with possible spatio-temporal overlap among populations with differing population trends. Successful harvest management in such situations requires knowledge about the connections between breeding and non-breeding locations, and where birds are harvested. Breeding populations of Eurasian wigeon (Mareca penelope) are declining in Finland, underlining the need for more effective harvest management. Relative proportions and temporal distribution of local breeding birds and migrants from a larger Russian breeding population within the Finnish hunting bag has been unknown to date. We studied spatio-temporal origins of Finnish harvested wigeon by measuring stable-hydrogen (δ2H) isotope values from legally harvested birds. We modelled the changes in δ2H values of the feather samples within the hunting season using Gaussian processes and found that the origin of harvested wigeon in Finland changed during the hunting season and differed by age and sex. In juveniles and adult females but not in adult males, origin of harvested birds shifted from local and possibly western Russian birds to more long-distance migratory birds during the harvest season. These patterns likely reflected sex- and age-specific differences in migratory behaviour of Eurasian wigeon in the East Atlantic flyway, which can be used to guide future management and conservation of this species through the implementation of spatio-temporal harvest regulation.

Deteriorating wintertime habitat conditions for waterfowls in Caizi Lake, China: Drivers and adaptive measures

China has made enormous strides to achieve high-quality development and biodiversity conservation, and the establishment of nature-protected areas is one of the essential initiatives. Caizi Lake involves a natural reserve and two national wetland parks, accommodating winter migratory waterfowl over the middle and lower Yangtze River basin in China. However, the water transfer from the Yangtze River to the Huai River (YR-HR water transfer) has modified the winter hydrological conditions of Caizi Lake, negatively affecting wintertime waterfowl habitats. Hence, conserving wintertime waterfowl habitats necessitates knowledge of the dynamical mechanisms behind the impacts of YR-HR water transfer on wintertime waterfowl habitats and adaptive measures. Here we developed a machine learning model, the normalized difference vegetation index, and on-spot observatory datasets such as the spatial distribution of waterfowl species and underwater topography of Caizi Lake. We found that the rising winter water level of Caizi Lake encroaches on winter waterfowl habitat with extremely high suitability. Meanwhile, rising water levels reduced waterfowl food sources. Thus, rising water levels due to YR-HR water transfer deteriorated waterfowl living conditions over Caizi Lake. Therefore, we proposed adaptive measures to alleviate these negative effects, such as water level regulation, artificial feeding of waterfowls, restoration and reconstruction of contiguous mudflats, grass flats. This study highlights human interferences with waterfowl habitats, necessitating biodiversity conservation at regional scales.

Migratory herbivorous waterfowl track multiple resource waves during spring migration.

East Asian herbivorous waterfowl intensively use farmland in spring, next to their natural habitat. Accordingly, they might have expanded their migration strategy from merely tracking the green wave of newly emerging vegetation to also incorporating the availability of post-harvest agricultural seeds (here dubbed the seed wave). However, if and how waterfowl use multiple food resources to time their seasonal migration is still unknown. We test this migration strategy using 167 spring migration tracks of five East Asian herbivorous waterfowl species and mixed-effect resource selection function models. We found that all study species arrived at their core stopover sites in the Northeast China Plain after agricultural seeds became available, extended their stay after spring vegetation emerged and arrived at their breeding sites around the emergence of vegetation. At the core stopover sites, all study species used snowmelt as a cue to track seed availability, although smaller-bodied species tended to arrive later. At the breeding sites, swans tracked the onset of vegetation emergence and geese tracked the mid- or end phases of snowmelt. Our findings suggest that waterfowl track multiple resource waves to fine-tune their migration, highlighting new opportunities for conservation.

Long‐term observation of waterfowl migration in the south‐east of the forest zone of Western Siberia, Russia

The aim of this research is an analysis of the long‐term dynamics of the composition and number of migratory waterfowl in the southeast of the forest zone of Western Siberia.Visual observations of waterfowl migration were carried out in the format of daily 2‐hour morning counts in April‐May through a period 18 years (1998–2023) near the Tomsk on the Tom river. Additionally, in 2002–2003, simultaneous migration was also observed on the Ob river in the southern, central and northern parts of the Tomsk region. The method of E.I. Gavrilova and E.V. Kumari was used with some modifications. Birds were counted which were transit flying via the territory, as well as birds sitting on the lake water in the area of the observation point.Twenty‐one species of waterfowl have been registered. Analysis of long‐term dynamics has revealed a trend towards a decrease in the total number of migrating waterfowl. In the most abundant species, Anas acuta, this trend is statistically significant. In some species – Anas strepera and Cygnus Cygnus – the trend of dynamics is positive.Most likely reason for the decline in waterfowl numbers is excessive spring hunting. A reduced hunting duration or the introduction of a moratorium every few years may be among the responses required. We suggest using the period of mass migration to monitor the waterfowl resource. This period is shorter and when the greatest number of birds migrate.

The first report and biological characterization of Avian Orthoavulavirus 16 in wild migratory waterfowl and domestic poultry in China reveal a potential threat to birds

ABSTRACT The Avulavirus within the family Paramyxoviridae includes at least 22 different species, and is known to cause different types of infections and even be fatal in multiple avian species. There is limited knowledge of the genetic and biological information of Avulavirus species 2 to 22 in domestic and wild birds and the disease significance of these viruses in birds is not fully determined, although as many as 10 new distinct species have been identified from wild birds and domestic poultry around the world in the last decade. This study aimed to use PCR, virus isolation, and sequencing to genetically and biologically characterize Avian Orthoavulavirus 16 (AOAV-16) in wild birds and domestic poultry collected from different locations in China between 2014 and 2022. Of five isolated AOAV-16 strains (Y1 to Y5), only the Y4 strain had a haemagglutination (HA)-negative result. All of these isolates were low virulent viruses for chickens, except Y3 which was detected simultaneously with avian influenza virus (AIV) of H9N2 subtype. Furthermore, at least four different types of intergenic sequences (IGS) between the HN and L genes junction, and recombination events, as well as interspecific transmission by wild migratory birds, existed within the species AOAV-16. These findings and results of other reported AOAV-16 strains recommend strict control measures to limit contact between wild migratory birds and domestic poultry and imply potential threats to commercial poultry and even public health challenges worldwide. RESEARCH HIGHLIGHTS First confirmation of AOAV-16 in domestic and wild birds in China. AOAV-16 are low virulent viruses for chickens. Co-circulation/co-infection of AOAV-16 and H9N2 subtype AIV enhanced pathogenicity. Different intergenic sequences and recombination events exist within AOAV-16.

Using an adaptive modeling framework to identify avian influenza spillover risk at the wild-domestic interface

The wild to domestic bird interface is an important nexus for emergence and transmission of highly pathogenic avian influenza (HPAI) viruses. Although the recent incursion of HPAI H5N1 Clade 2.3.4.4b into North America calls for emergency response and planning given the unprecedented scale, readily available data-driven models are lacking. Here, we provide high resolution spatial and temporal transmission risk models for the contiguous United States. Considering virus host ecology, we included weekly species-level wild waterfowl (Anatidae) abundance and endemic low pathogenic avian influenza virus prevalence metrics in combination with number of poultry farms per commodity type and relative biosecurity risks at two spatial scales: 3 km and county-level. Spillover risk varied across the annual cycle of waterfowl migration and some locations exhibited persistent risk throughout the year given higher poultry production. Validation using wild bird introduction events identified by phylogenetic analysis from 2022 to 2023 HPAI poultry outbreaks indicate strong model performance. The modular nature of our approach lends itself to building upon updated datasets under evolving conditions, testing hypothetical scenarios, or customizing results with proprietary data. This research demonstrates an adaptive approach for developing models to inform preparedness and response as novel outbreaks occur, viruses evolve, and additional data become available.

Highly Pathogenic Avian Influenza (HPAI) H5 Clade 2.3.4.4b Virus Infection in Birds and Mammals.

Avian influenza viruses (AIVs) are highly contagious respiratory viruses of birds, leading to significant morbidity and mortality globally and causing substantial economic losses to the poultry industry and agriculture. Since their first isolation in 2013-2014, the Asian-origin H5 highly pathogenic avian influenza viruses (HPAI) of clade 2.3.4.4b have undergone unprecedented evolution and reassortment of internal gene segments. In just a few years, it supplanted other AIV clades, and now it is widespread in the wild migratory waterfowl, spreading to Asia, Europe, Africa, and the Americas. Wild waterfowl, the natural reservoir of LPAIVs and generally more resistant to the disease, also manifested high morbidity and mortality with HPAIV clade 2.3.4.4b. This clade also caused overt clinical signs and mass mortality in a variety of avian and mammalian species never reported before, such as raptors, seabirds, sealions, foxes, and others. Most notably, the recent outbreaks in dairy cattle were associated with the emergence of a few critical mutations related to mammalian adaptation, raising concerns about the possibility of jumping species and acquisition of sustained human-to-human transmission. The main clinical signs and anatomopathological findings associated with clade 2.3.4.4b virus infection in birds and non-human mammals are hereby summarized.

Isolation and genetic characterization of multiple genotypes of both H5 and H7 avian influenza viruses from environmental water in the Izumi plain, Kagoshima prefecture, Japan during the 2021/22 winter season

In the 2021/22 winter, one H5N1 and nine H5N8 high pathogenicity avian influenza viruses (HPAIVs) of clade 2.3.3.4b were isolated from the water in crane roosts on the Izumi plain, Japan. Additionally, we isolated low pathogenicity avian influenza viruses (LPAIVs) of five subtypes: H1N1, H4N2, H4N6, H7N7, and H10N4. H5N8 HPAIVs belonging to the G2a group were isolated throughout winter, whereas H5N1 HPAIV belonging to the G2b group were isolated only in early winter. These findings suggest co-circulation of both G2a and G2b HPAIVs in early winter. Although two H7N7 LPAIVs were isolated from cranes’ roost water collected on the same day, the gene constellations of the two isolates were clearly different, indicating the contemporary invasion of at least two different genotypes of H7N7 LPAIVs in the Izumi plain. This study underscores the importance of monitoring both HPAIVs and LPAIVs to understand avian influenza virus ecology in migratory waterfowl populations.

Identifying an Understudied Interface: Preliminary Evaluation of the Use of Retention Ponds on Commercial Poultry Farms by Wild Waterfowl

While the recent incursion of highly pathogenic avian influenza into North America has resulted in notable losses to the commercial poultry industry, the mechanism by which virus enters commercial poultry houses is still not understood. One theorized mechanism is that waterfowl shed virus into the environment surrounding poultry farms, such as into retention ponds, and is then transmitted into poultry houses via bridge species. Little is known about if and when wild waterfowl use these retention ponds, leading to uncertainty regarding the potential significance of this interface. To quantify the use of retention ponds on commercial poultry farms by wild waterfowl, we surveyed 12 such ponds across Somerset and Dorchester counties, Maryland, USA. This region was chosen due to the high level of poultry production and its importance for migratory waterfowl. Surveys consisted of recording waterfowl visible on the retention ponds from public roadways at least once per week from 20 September 2022–31 March 2023. Throughout the course of this study, we observed a total of nine species of waterfowl using retention ponds on commercial poultry farms at nine of 12 sites. The number of waterfowl observed at retention ponds varied notably throughout the course of our survey period, with values generally following trends of fall migration within each species indicating that resident birds were not the only individuals to utilize these habitats. Additionally, waterfowl use was highest at sites with little vegetation immediately surrounding the pond, and lowest when ponds were surrounded by trees. Our data suggest that retention ponds on commercial poultry farms present a notable interface for waterfowl to introduce avian influenza viruses to farm sites. However, additional testing and surveys could provide further insight into whether it may be possible to reduce the use of these habitats by wild waterfowl through vegetative management as preliminarily reported here.

Where east meets west: Phylogeography of the high Arctic North American brant goose.

Genetic variation in Arctic species is often influenced by vicariance during the Pleistocene, as ice sheets fragmented the landscape and displaced populations to low- and high-latitude refugia. The formation of secondary contact or suture zones during periods of ice sheet retraction has important consequences on genetic diversity by facilitating genetic connectivity between formerly isolated populations. Brant geese (Branta bernicla) are a maritime migratory waterfowl (Anseriformes) species that almost exclusively uses coastal habitats. Within North America, brant geese are characterized by two phenotypically distinct subspecies that utilize disjunct breeding and wintering areas in the northern Pacific and Atlantic. In the Western High Arctic of Canada, brant geese consist of individuals with an intermediate phenotype that are rarely observed nesting outside this region. We examined the genetic structure of brant geese populations from each subspecies and areas consisting of intermediate phenotypes using mitochondrial DNA (mtDNA) control region sequence data and microsatellite loci. We found a strong east-west partition in both marker types consistent with refugial populations. Within subspecies, structure was also observed at mtDNA while microsatellite data suggested the presence of only two distinct genetic clusters. The Western High Arctic (WHA) appears to be a secondary contact zone for both Atlantic and Pacific lineages as mtDNA and nuclear genotypes were assigned to both subspecies, and admixed individuals were observed in this region. The mtDNA sequence data outside WHA suggests no or very restricted intermixing between Atlantic and Pacific wintering populations which is consistent with published banding and telemetry data. Our study indicates that, although brant geese in the WHA are not a genetically distinct lineage, this region may act as a reservoir of genetic diversity and may be an area of high conservation value given the potential of low reproductive output in this species.

Community-science reveals delayed fall migration of waterfowl and spatiotemporal effects of a changing climate.

Climate change has well-documented, yet variable, influences on the annual movements of migratory birds. The effects of climate change on fall migration remains understudied compared with spring but appears to be less consistent among species, regions and years. Changes in the pattern and timing of waterfowl migration in particular may result in cascading effects on ecosystem function, and socio-economic and cultural outcomes. We investigated changes in the migration of 15 waterfowl species along a major flyway corridor of continental importance in northeastern North America using 43 years of community-science data. We built spatially- and temporally explicit hierarchical generative additive models for each species and demonstrated that climate, specifically the interaction between minimum temperature and precipitation, significantly influences migration phenology for most species. Certain species' migratory movements responded to specific temperature thresholds (climate migrants) and others reacted more to the interaction of temperature and precipitation (extreme event migrants). There are already significant changes in the fall migration phenology of common waterfowl species with high ecological and economic importance, which may simply increase in the context of a changing climate. If not addressed, climate change could induce mismatches in management, regulations and population surveys which would negatively impact the hunting industry. Our findings highlight the importance of considering species-specific spatiotemporal scales of effect on climate on migration and our methods can be widely adapted to quantify and forecast climate-driven changes in wildlife migration.

Genetic Characterization of Avian Paramyxovirus Isolated from Wild Waterfowl in Korea between 2015 and 2021.

Avian paramyxoviruses (APMVs) are often carried by wild waterfowl, and the wild waterfowl may play an important role in the maintenance and spread of these viruses. In this study, we investigated APMVs in the population of migratory wild waterfowl from 2015 to 2021 in Korea and analyzed their genetic characteristics. Fourteen viruses were isolated and subsequently identified as APMV-1 (n = 13) and APMV-13 (n = 1). Phylogenetic analysis of the full fusion gene of 13 APMV-1 isolates showed that 10 APMV-1 isolates belonged to the class II sub-genotype I.2, which was epidemiologically linked to viruses from the Eurasian continent, and 3 viruses belonged to class I, which linked to viruses from the USA. The APMV-13 isolates from wild geese in this study were highly homology to the virus isolated from China. Sequence analysis of 14 isolates showed that all isolates had a typical lentogenic motif at the cleavage site. In summary, we identified the wild species likely to be infected with APMV and our data suggest possible intercontinental transmission of APMV by wild waterfowl. Our current study also provides the first evidence for the presence of class I of APMV-1 and APMV-13 in wild waterfowl surveyed in Korea.

Evolution and biological characteristics of the circulated H8N4 avian influenza viruses1

The circulating avian influenza viruses in wild birds have a high possibility of spillover into domestic birds or mammals at the wild bird-domestic bird or bird-mammal interface. H8N4 viruses primarily circulate in migratory wild waterfowl and have rarely been identified in domestic birds. In this study, we summarized the spatial and temporal distribution of global H8 viruses, specified their natural reservoirs, and performed detailed evolutionary analysis on the dominant H8N4 viruses. Here, we also reported a novel H8N4 virus isolated from a Eurasian coot sample from a wetland in eastern China in 2022. Animal infection studies indicated that the wild bird-originated H8N4 virus can replicate and transmit efficiently in ducks but has not adapted to chickens. Additionally, this naturally isolated H8N4 virus can replicate in mice without prior adaptation. These results indicate that H8 viruses exist mainly in the wild duck reservoir and pose a high infection risk to domestic ducks. Therefore, the active surveillance of influenza viruses at the wild and domestic waterfowl interface will contribute to monitoring the circulation of these viruses.

Spatially heterogeneous shifts in vegetation phenology induced by climate change threaten the integrity of the avian migration network.

Phenological responses to climate change frequently vary among trophic levels, which can result in increasing asynchrony between the peak energy requirements of consumers and the availability of resources. Migratory birds use multiple habitats with seasonal food resources along migration flyways. Spatially heterogeneous climate change could cause the phenology of food availability along the migration flyway to become desynchronized. Such heterogeneous shifts in food phenology could pose a challenge to migratory birds by reducing their opportunity for food availability along the migration path and consequently influencing their survival and reproduction. We develop a novel graph-based approach to quantify this problem and deploy it to evaluate the condition of the heterogeneous shifts in vegetation phenology for 16 migratory herbivorous waterfowl species in Asia. We show that climate change-induced heterogeneous shifts in vegetation phenology could cause a 12% loss of migration network integrity on average across all study species. Species that winter at relatively lower latitudes are subjected to a higher loss of integrity in their migration network. These findings highlight the susceptibility of migratory species to climate change. Our proposed methodological framework could be applied to migratory species in general to yield an accurate assessment of the exposure under climate change and help to identify actions for biodiversity conservation in the face of climate-related risks.

Population genetics of Artemia urmiana species complex (Crustacea, Anostraca): A group with asymmetrical dispersal and gene flow mediated by migratory waterfowl

Bird-mediated dispersal of resting eggs is the main mechanism for Artemia dispersal among catchments. The bisexual populations of Artemia urmiana species complex, which is here considered to be a collection of Artemia genetically close to the so-called “Western Asian Lineage”, are mostly distributed in central and western Asia (i.e., in regions falling into the Central Asian Flyway of migratory birds) and live in diversified habitats. Little is known about the genetic relationships among these populations. Aiming to understand the population genetic characteristics and the roles of migratory birds on the dispersal and gene flow of this Artemia group, we evaluated the genetic diversity, genetic differentiation, and gene flow among 14 populations, with their altitudes ranging from 540 to 4870 m above sea level, using 13 microsatellite markers. Almost all populations exhibited high genetic diversity and heterozygote excess, which may be a consequence of combined effects of dispersal and hybridization. The global genetic differentiation (FST) value was 0.092, the pairwise FST values were 0.003–0.246. Discriminant analysis of principal components identified three genetic clusters, consisting of Urmia Lake (Iran), Zhundong (Xinjiang, China), and 12 Qinghai-Tibet Plateau populations, respectively. The among-population genetic differentiation seems to be a consequence of isolation by distance and adaptation to diversified habitats induced by altitudinal gradient. Historical gene flows are asymmetrical, and show an evolutionary source-sink dynamics, with Jingyu Lake (Xinjiang, China) population being the major source. These results support our hypothesis that in Qinghai-Tibet Plateau and surrounding areas the bird-mediated dispersal of Artemia may be biased towards from north to south and/or from higher altitude to lower altitude.

Drivers of hydrologic budgets in small terminal lakes in the Alberta prairies

The prairies and boreal plain within the North Saskatchewan Watershed (NSW) of Central Alberta have numerous shallow ponds and lakes that sustain unique aquatic ecosystems and are critical habitat for migratory waterfowl in North America. However, over the past 20 years water levels have declined and the reasons are unresolved. Here we used a combination of inorganic geochemical analyses and stable water isotopes to constrain the hydrologic budgets of six lakes in the NSW. Our results show that the bedrock groundwater major element geochemistry is controlled by chemical weathering reactions along the flow paths and is dominated by lower δ18O and δ2H values (i.e. isotopically depleted), while the lake water generally shows unchanging evaporatively enriched stable isotope values and cation concentrations. An isotopic mass balance (IMB) technique combined with solution geochemical modelling using activity – activity plots reveals that deep groundwater input is negligible, while the lakes appear to lose a greater fraction of water inflows to evaporation (60%) than shallow groundwater and surface outflow (40%). The relative importance of shallow groundwater requires further study, as shallow groundwater sampling locations are scarce and surface outflow is negligible. The IMB technique also indicated that these prairie lakes have short water residence times, ranging from 1.8 to 10.4 yrs. Our results suggest that declining lake levels are likely the result of a changing relationship between precipitation and evaporation from the climatic norm.

Daphnia magna (Crustacea: Anomopoda) in central Mexico wetlands: implications of escape from ecotoxicological laboratories

Daphnia (Ctenodaphnia) magna, a species widely used for ecotoxicological tests, was recorded for the first time in waterbodies of the Mexican protected area and RAMSAR site Ciénegas del Lerma. The identity of the species was confirmed using morphological traits and cytochrome oxidase I as a molecular marker. Haplotypes were 100% identical to cultures used in laboratory bioassays in México and Canada. Individuals analyzed are related to strains from Europe, and their sequences differed from natural populations reported from the United States of America and Canada. This Mexican wetland supports a rich community of migratory waterfowl; therefore, D. magna could quickly spread to other waterbodies and cause potential adverse effects on local Daphnia species. The utilization of non-native species in ecotoxicological tests must be undertaken with great care, to ensure escape to natural waters is prevented.