Wetland-associated Species Research Articles

The habitat preferences of invasive raccoon dog imply elevated risks for wetland-associated prey species

Habitat preferences of invasive predators determine where and for which prey species they pose a threat upon. This is crucial information for the conservation of endangered prey species because invasive predators pose additional predation on top of that caused by natural predators. In large parts of Europe, the most common invasive mesopredator is the raccoon dog (Nyctereutes procyonoides). To understand the risk that the raccoon dog poses for wetland-associated species, we collected information about its habitat preferences near these habitats. We used data on 24 GPS-collared raccoon dogs from three landscape types in Finland, to study their spatial and temporal habitat preferences. We first determined their home ranges, within which we then examined habitat use and preferences. Raccoon dogs showed generalist habitat use, which was evident in their wide range of used habitats. However, in spring and summer, during the breeding seasons of waterfowl and amphibians, they preferred wetlands and peatlands. They also preferred shorelines and the edges of forests and agricultural fields. During autumn and winter, raccoon dogs did not prefer wetlands. These findings support the conclusion that the raccoon dog’s habitat preferences pose a particular threat to wetland-associated species, such as nesting waterfowl and amphibians. The species’ habitat preferences coupled with high numbers of this invasive mesopredator pose additional predation for endangered wetland-associated species on top of that of native predators.

Composition and Conservation Status of Avifauna in Urban Non-protected Important Bird Area (IBA) Site of Western India

Kumbharwada wetland, an Important Bird Area (IBA) component in Bhavnagar, Gujarat, India, is a crucial wintering ground for migratory birds. Long-term monitoring of the avian community over a period of long time-frame is an excellent way to examine the health of this IBA site and thus provide an important ground to foster the conservation of birds in the region and management of this wetland. Given this consideration, field surveys were carried out from December 2020 to May 2023, following point count method to study the avian species richness in the study area. A total of 204 bird species belonging to 20 orders and 56 families are recorded, of which 85 species are migratory and 119 are resident. Anatidae is the most species-rich avian family (16 species). Highest number of species was recorded in the month of January (165 species in 2021 and 163 species in 2022). This wetland supports 107 (52.45%) wetland-associated species and 97 (47.55%) terrestrial species of birds. Twelve species are considered as Near Threatened, four species as Vulnerable and one species (Aquila nipalensis) as Endangered in IUCN Red List of Threatened Species. Four species (Sterna aurantia, Mycteria leucocephala, Phoeniconaias minor, and Threskiornis melanocephalus) with globally declining trend, are commonly seen in the study area, which shows that the wetland is a crucial habitat for bird species with high conservation priorities. Industrialization, encroachment, discharge of sewage water and chemical effluents, high-tension powerlines, stray dogs, and expansion of exotic vegetation remained the major threats to the habitat and avian community.

Combined analysis of roadside and off-road breeding bird survey data to assess population change in Alaska

ABSTRACT Management interest in North American birds has increasingly focused on species that breed in Alaska, USA, and Canada, where habitats are changing rapidly in response to climatic and anthropogenic factors. We used a series of hierarchical models to estimate rates of population change in 2 forested Bird Conservation Regions (BCRs) in Alaska based on data from the roadside North American Breeding Bird Survey (BBS) and the Alaska Landbird Monitoring Survey, which samples off-road areas on public resource lands. We estimated long-term (1993–2015) population trends for 84 bird species from the BBS and short-term (2003–2015) trends for 31 species from both surveys. Among the 84 species with long-term estimates, 11 had positive trends and 17 had negative trends in 1 or both BCRs; negative trends were primarily found among aerial insectivores and wetland-associated species, confirming range-wide negative continental trends for many of these birds. Three species with negative trends in the contiguous Unit...

Factors influencing herpetofaunal assemblages of aquatic systems in a managed pine forest

Although >12 million ha of southeastern United States are intensively managed pine forest, we have little understanding of biological contributions of aquatic systems embedded in pine plantations. Further, the influence surrounding forest stand structure on assemblages of wetland-associated species in managed forests are poorly understood. To address these gaps, we investigated herpetofaunal assemblages across three ephemeral aquatic system types [unaltered sites (n=16), altered sites (n=18), and roadside ditches (n=19)] embedded in an intensively managed pine landscape in eastern North Carolina, USA. These aquatic systems varied in their disturbance intensity and landscape context. Unaltered sites were avoided by silvicultural activities (set aside), altered sites were actively managed as part of the surrounding plantation, and ditches received maintenance as part of routine forest management. We examined amphibian and reptile species richness and assemblage composition at 53 aquatic sites surrounded by early-, middle-, or late-rotation aged pine plantations. During January–July 2013 and January–June 2014, we detected 34 amphibian and reptile species with visual encounter, dipnet, and call surveys at aquatic sites. We estimated species richness and used Analysis of Similarity to assess differences in species richness and assemblage structure by aquatic system type and stand age class. Amphibian species richness was greatest in unaltered and altered sites but was similar among stand age classes. Reptile species richness was similar among aquatic system types and stand age classes. Analysis of Similarity results revealed that amphibian assemblages were similar among stand age classes but were significantly different among all aquatic systems. Reptile assemblages also were similar among stand age classes but differed between altered sites and roadside ditches. Differences between richness and assemblage results may have been related to low detections of reptiles because our non-metric multi-dimensional scaling analysis, which only included species with >1 detection, revealed less obvious differences among reptile assemblages by aquatic system type. Despite dramatic variation in disturbance intensity and site-level environmental metrics, we did not find distinct herpetofaunal assemblages among aquatic system types or stand age classes. Our results suggest that aquatic systems in reconfigured landscapes not only support a range of herpetofaunal species, but that amphibian and reptile assemblages are similar across system types.

Assessment of Diurnal Wind Turbine Collision Risk for Grassland Birds on the Southern Great Plains

AbstractWind energy is one of the fastest growing renewable energy sources in the United States and has the potential to reduce the use of traditional nonrenewable energy. However, there is concern for potential short- and long-term influences on wildlife populations, such as bird collisions with turbine blades, habitat loss, habitat fragmentation, and habitat avoidance. Bird flight heights are indicative of collision risks, but knowledge of their distributions is limited. Our goal was to examine the diurnal flight heights of bird species to assess which are at greatest risk of collision with wind turbine blades. During October 2008–August 2009, we estimated the flight heights of 66 bird species at a planned wind energy facility on the southern Great Plains. Flight heights were estimated by measuring angle of incline with a clinometer and ground distance with a laser rangefinder. Previous work has been limited to flight height measurements categorized to site-specific rotor swept zone (RSZ) specifications that has resulted in limited applicability to other wind turbine RSZ specifications. Our research is distinctive because it provides more resolution in flight height estimates than those categorized into bins and allows application to wind turbines with different RSZs. We found that the flight heights of six bird species varied among seasons, indicating their risk of collision changed throughout the year. Observations indicated that the average flight heights of 28 bird species were within the potential RSZ (32–124 m above ground level) at our study site and that two species exhibited mean flight heights above the RSZ. Fifteen of those species were wetland-associated species, 7 were raptor or vulture species, and 6 were listed as species of greatest conservation need by Texas Parks and Wildlife Department. We observed 14 bird species (1 vulture, 2 raptors, 7 wetland-associated species, and 4 passerines or other species) with greater than 25% of their observed flight heights within the RSZ. Our results indicate that raptors and wetland-associated species are the avian groups at greatest risk of collision with wind turbines due to their diurnal flight heights. However, the resolution of our data will allow assessment of which bird species are at greatest risk of collision for various wind turbine specifications. This information can help guide site assessment and placement for wind energy facilities across the southern Great Plains and help mitigate potential collision impacts on bird species.

Biogeographic and Conservation Significance of the Occurrence of the Canadian EndemicSorex maritimensis(Maritime Shrew) in Northern New Brunswick

Sorex maritimensis (Maritime Shrew) is endemic to New Brunswick and Nova Scotia. We suggest that post-glacial dispersal northward by this species from a coastal plain refugium located in the mid-Atlantic, rather than dispersal from a refugium off Nova Scotia as previously proposed, is more parsimonious with current understanding of the glacial history of the region. A range extension into northeastern New Brunswick shows that the species is distributed north—south in New Brunswick and suggests that wetlands in heavily forested regions meet the ecological requirements of the Maritime Shrew. Such wetlands may provide avenues for dispersal and ensure connectivity among populations. Habitat descriptions for the Maritime Shrew indicate a wetland-associated species adaptable enough to utilize disturbance-dominated and anthropogenic wetlands. Further investigations of the biology of the Maritime Shrew are required to inform future habitat and wetland protection policies that should consider the requirements of this poorly known Canadian mammal.

Low Prevalence of Chytrid Fungus (Batrachochytrium dendrobatidis) in Amphibians of U.S. Headwater Streams

Abstract Many declines of amphibian populations have been associated with chytridiomycosis, a disease caused by the aquatic fungus Batrachochytrium dendrobatidis (Bd). Despite the relatively high prevalence of chytridiomycosis in stream amphibians globally, most surveys in North America have focused primarily on wetland-associated species, which are frequently infected. To better understand the distribution and prevalence of Bd in headwater amphibian communities, we sampled 452 tailed frogs (Ascaphus truei and Ascaphus montanus) and 304 stream salamanders (seven species in the Dicamptodontidae and Plethodontidae) for Bd in 38, first- to third-order streams in five montane areas across the United States. We tested for presence of Bd by using PCR on skin swabs from salamanders and metamorphosed tailed frogs or the oral disc of frog larvae. We detected Bd on only seven individuals (0.93%) in four streams. Based on our study and results from five other studies that have sampled headwater- or seep-associated a...

Survey Techniques for Determining Occupancy of Isolated Wetlands by Round-tailed Muskrats

Neofiber alleni (round-tailed muskrat) is a wetland-associated species of conservation concern restricted to the southeastern United States. This species is relatively unstudied and no standardized procedures exist for determining its distribution. We evaluated a survey technique for assessing presence-absence of round-tailed muskrats in small, isolated, freshwater marshes in central Florida. We conclude that ≥ 2 trained persons searching adjacent belt transects on foot for ≤ 30 min during fall–early winter can reliably determine occupancy for muskrats based on presence of their distinctive lodges. Resurveys of unoccupied wetlands did not reveal any false absences from our initial survey, and an investigation of lodge persistence indicated that false presences were unlikely. Broad-scale studies of distributional patterns and temporal trends in occupancy of the round-tailed muskrat are needed to assess its conservation status and threats.

Distribution, Habitat Characteristics, and Population Trends of the Rare Southeastern Endemic Rudbeckia auriculata (Perdue) Kral (Asteraceae)

Rudbeckia auriculata is a rare wetland-associated species endemic to three southeastern states: Alabama, Florida, and Georgia. This study includes eight censuses of flowering individuals of the species during the ten-year period from 1992 to 2002. Although the number of known populations has increased during this time, the total number of flowering stems has remained relatively constant. Population size ranged from a single flowering stem to populations with over 1,000 flowering stems. Information on soils and associated species of vascular plants was collected at 20 of the 32 known sites during 1999, 2000, and 2001. Typical sites for the plant are located on wet soils along roadsides, power line right-of-ways or other disturbed sites. Associated species are those characteristic of disturbed open wetland sites. Although some large colonies of R. auriculata still exist, only two populations, both in the northern portion of the species' range, have been protected.

Wetland and upland use patterns in semi-aquatic snakes: Implications for wetland conservation

Conservation efforts require detailed knowledge of a species' habitat use and movements about the landscape. We radio-tracked sympatric congeners, the Copperbelly Water Snake (Nerodia erythrogaster neglecta) and the Northern Water Snake (Nerodia sipedon sipedon) in northwestern Ohio and southern Michigan, USA, to investigate differences in the use of wetland and upland habitats between species. Nerodia erythrogaster neglectaused twice as many wetlands (4.1 6 0.4) as N. s. sipedon (2.1 6 0.3), moved between these wetlands three times more often (9.1 6 1.9 times) than N. s. sipedon (2.8 6 1.0 times), and moved to small wetlands seven times more often (3.6 6 0.7 times) than N. s. sipedon (0.5 6 0.3 times). Nearly 30% of N. e. neglecta locations were in uplands, sometimes over 100 m from the nearest wetland. Less than 3% of N. s. sipedon locations were in upland habitats, and all locations were , 30 m from wetlands. We simulated the impact of small wetland loss and demonstrated that N. e. neglecta would need to move longer than normal distances when traveling between wetlands after small wetlands are lost, while N. s. sipedon would not. The northernmost populations of N. e. neglecta are listed as federally threatened and state en- dangered in Ohio, Michigan, and Indiana; N. s. sipedon remains abundant in this region. Historic and current wetland losses in the midwestern United States may have severely impacted N. e. neglecta populations due to this species' high vagility and use of numerous wetlands. Protection and restoration of wetland landscapes are critical for the long-term persistence of many wetland-associated species, including N. e. neglecta.