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USGS2002

Does increasing daylength control seasonal changes in clutch sizes of Northern Pintails ( Anas acuta )?

We evaluated spatiotemporal variation in clutch sizes of Northern Pintails (pintails; Anas acuta ) nesting in California (1985 to 1996), North Dakota (1982 to 1985), Saskatchewan (1982 to 1985) and Alaska (1991 to 1993) to determine whether seasonal declines in clutch size varied in ways that were consistent with a controlling influence of increasing day length. Pintails began nesting in mid-March in California, mid-April in North Dakota and Saskatchewan, and mid-May in Alaska. Observed durations of nesting were 70 ± 2.6 days (SE) in California, 60 ± 6.3 days in North Dakota, 66 ± 1.3 days in Saskatchewan, and 42 ± 0.7 days in Alaska. Annual differences were the principal source of variation in mean clutch sizes (σ̂ Y 2 = 0.15, SE = 0.049), which varied little among study locations (σ̂ A 2 = 0.002, SE = 0.013). Predicted rates of seasonal decline in clutch sizes increased with latitude early in the nesting season, but declined as the nesting season progressed, except in California. Rates of decline in clutch sizes thus were not directly related to rates of increase in day length. Predicted declines in numbers of eggs per clutch over the nesting season were similar for all four locations (range, 3.05–3.12) despite wide variation in durations of nesting. Evidence suggests that reduced nutrient availability during nesting contributes to a higher rate of decline in clutch sizes in Alaska than in temperate regions. Pintails that nest early lay large initial clutches, but thereafter clutch sizes decline rapidly and breeding terminates early. This reproductive strategy is adaptive because young that hatch earliest exhibit the highest survival rates; however, the conversion of grassland to cropland on the primary prairie breeding grounds has reduced hatching rates of clutches laid early in the nesting season. Under these conditions, the limited capacity to renest in late spring on their prairie breeding grounds probably has contributed to Pintail population declines.

The Auk↗

USGS2018

Diel fledging patterns among grassland passerines: Relative impacts of energetics and predation risk

The time of day that nestlings fledge from a nest is thought to be shaped by predation risk and energetics. To minimize predation risk, fledging is predicted to start as early in the day as possible so that nestlings can maximize time outside the nest to find a safe place to stay before nightfall. Fledging times are predicted to be tightly grouped and to not be affected by the number of nestlings, given that all nestlings are responding to the same relative risk of predation. Conversely, energetic considerations predict that fledging time of day should vary so that nestlings can maximize energy intake before having to forage for themselves. However, data to evaluate the relative importance of these drivers in grassland birds are scarce because of the difficulty of observing nestlings as they fledge. We used nest surveillance video from 178 nests to evaluate how the initiation and duration of fledging varied among 7 grassland passerine species, as well as by the number of nestlings in the nest and fledging date. Fledging initiation varied most strongly by species, with some effects of date. Across species, the median start time of fledging was 4.55 hr after sunrise. Fledging before the solstice started ∼30 min earlier compared to fledging at or after the solstice. Fledging duration increased with number of nestlings in the nest and was spread over >1 day in 21% of nests. While our results primarily supported the hypothesis that fledging is motivated by energetic considerations, additional data on basic life history traits and behavior will be needed to fully understand how fledging grassland birds balance energetics against predation risk.

The Auk↗

USGS2012

Mapping anuran habitat suitability to estimate effects of grassland and wetland conservation programs

The conversion of the Northern Great Plains of North America to a landscape favoring agricultural commodity production has negatively impacted wildlife habitats. To offset impacts, conservation programs have been implemented by the U.S. Department of Agriculture and other agencies to restore grassland and wetland habitat components. To evaluate effects of these efforts on anuran habitats, we used call survey data and environmental data in ecological niche factor analyses implemented through the program Biomapper to quantify habitat suitability for five anuran species within a 196 km 2 study area. Our amphibian call surveys identified Northern Leopard Frogs ( Lithobates pipiens ), Wood Frogs ( Lithobates sylvaticus ), Boreal Chorus Frogs ( Pseudacris maculata ), Great Plains Toads ( Anaxyrus cognatus ), and Woodhouse’s Toads ( Anaxyrus woodhousii ) occurring within the study area. Habitat suitability maps developed for each species revealed differing patterns of suitable habitat among species. The most significant findings of our mapping effort were 1) the influence of deep-water overwintering wetlands on suitable habitat for all species encountered except the Boreal Chorus Frog; 2) the lack of overlap between areas of core habitat for both the Northern Leopard Frog and Wood Frog compared to the core habitat for both toad species; and 3) the importance of conservation programs in providing grassland components of Northern Leopard Frog and Wood Frog habitat. The differences in habitats suitable for the five species we studied in the Northern Great Plains, i.e., their ecological niches, highlight the importance of utilizing an ecosystem based approach that considers the varying needs of multiple species in the development of amphibian conservation and management plans.

Copeia↗

USGS2024

Thermal traits of anurans database for the southeastern United States (TRAD): A database of thermal trait values for 40 anuran species

Thermal traits, or how an animal responds to changing temperatures, impacts species persistence and thus biodiversity. Trait databases, as repositories of consolidated, measured organismal attributes, allow researchers to link study species with specific trait values, enabling comparisons within and among species. Trait databases also help lay the groundwork to build mechanistic linkages between organisms and the environment. However, missing or hidden physiological trait data preclude building mechanistic estimates of climate change vulnerability for many species. Thus, physiologically focused trait databases present an opportunity to consolidate data and enable species-specific or multispecies, mechanistic evaluations of climate change vulnerability. Here, we present TRAD: thermal traits of anurans database for the southeastern United States, a database of thermal trait values related to physiological thermoregulation (critical thermal minima and maxima, preferred temperature), behavioral thermoregulation (activity period, retreat emergence temperature, basking temperature, minimum and maximum foraging temperatures), and body mass for 37 anuran species found within the southeastern United States. In total, TRAD contains 858 reported trait values for 37 of 40 species found in the region from 267 peer-reviewed papers, dissertations, or theses and is easily linked with trait data available in ATraiU, an ecological trait database for anurans in the United States. TRAD contains trait values for multiple life stages and a summarization of interspecific adult trait values. Availability of trait data varied widely among traits and species. Estimates of mass were the most common trait values reported, with values available for 32 species. Behavioral trait values comprised 23% of our database, with activity period available for 34 species. We found the most trait values for Cope's Gray Treefrog ( Dryophytes chrysoscelis ), with at least one trait value for eight traits in the database. Conversely, species in the genus Pseudacris generally had the fewest trait values available. Species with the largest geographic range sizes also had the greatest coverage of data across traits (rho 5 0.75, P , 0.001). TRAD can aid studies of anuran response to changing temperatures, physiological niche space and limitations, and potential drivers of anuran geographic range limits, influencing our understanding of other ecological and evolutionary patterns and processes and enabling multispecies comparisons of potential risk and resilience in the face of climate change.

southeastern United States↗

USGS2005

Comparative susceptibility of introduced forest-dwelling mosquitoes in Hawai'i to avian malaria, Plasmodium relictum

To identify potential vectors of avian malaria in Hawaiian native forests, the innate susceptibility of Aedes albopictus, Wyeomyia mitchellii, and Culex quinquefasciatus from 3 geographical sites along an altitudinal gradient was evaluated using local isolates of Plasmodium relictum. Mosquitoes were dissected 5-8 and 9-13 days postinfective blood meal and microscopically examined for oocysts and salivary-gland sporozoites. Sporogony was completed in all 3 species, but prevalence between species varied significantly. Oocysts were detected in 1-2% and sporozoites in 1-7% of Aedes albopictus that fed on infected ducklings. Wyeomyia mitchellii was slightly more susceptible, with 7-19% and 7% infected with oocysts and sporozoites, respectively. In both species, the median oocyst number was 5 or below. This is only the second Wyeomyia species reported to support development of a malarial parasite. Conversely, Culex quinquefasciatus from all 3 sites proved very susceptible. Prevalence of oocysts and sporozoites consistently exceeded 70%, regardless of gametocytemia or origin of the P. relictum isolate. In trials for which a maximum 200 oocysts were recorded, the median number of oocysts ranged from 144 to 200. It was concluded that Culex quinquefasciatus is the primary vector of avian malaria in Hawai'i. ?? American Society of Parasitologists 2005.

Journal of Parasitology↗

USGS2005

Population genetic analysis of Mountain Plover using mitochondrial DNA sequence data

Mountain Plover ( Charadrius montanus ) distribution and abundance have been reduced drastically in the past 30 years and the conversion of shortgrass prairie to agriculture has caused breeding populations to become geographically isolated. This, coupled with the fact that Mountain Plovers are thought to show fidelity to breeding grounds, leads to the prediction that the isolated breeding populations would be genetically distinct. This pattern, if observed, would have important management implications for a species at risk of extinction. Our study examined genetic variation at two mitochondrial regions for 20–30 individuals from each of four breeding sites. We found no evidence of significant population differentiation in the data from the control region or the ATPase 6/8 region. Nested-clade analysis revealed no relationship between haplotype phylogeny, and geography among the 47 control region haplotypes. In the ATPase 6/8 region, however, one of the two clades provided information suggesting that, historically, there has been continuous range expansion. Analysis of mismatch distributions and Tajima's D suggest that the Mountain Plover underwent a population expansion, following the Pleistocene glacial period. To explain the lack of detectable genetic differentiation among populations, despite their geographic isolation and fidelity to breeding locations, we speculate that there is sufficient female-mediated gene flow to homogenize gene pools among populations. Such gene flow might ensue if pair bonds are formed in mixed flocks on wintering grounds rather than on the summer breeding grounds.

The Condor↗

USGS2015

Breeding habitat associations and predicted distribution of an obligate tundra-breeding bird, Smith's Longspur

Smith's Longspur ( Calcarius pictus ) is a species of conservation concern which breeds in Arctic habitats that are expected to be especially vulnerable to climate change. We used bird presence and habitat data from point-transect surveys conducted at 12 sites across the Brooks Range, Alaska, 2003–2009, to identify breeding areas, describe local habitat associations, and identify suitable habitat using a predictive model of Smith's Longspur distribution. Smith's Longspurs were observed at seven sites, where they were associated with a variety of sedge–shrub habitats composed primarily of mosses, sedges, tussocks, and dwarf shrubs; erect shrubs were common but sparse. Nonmetric multidimensional scaling ordination of ground cover revealed positive associations of Smith's Longspur presence with sedges and mosses and a negative association with high cover of shrubs. To model predicted distribution, we used boosted regression trees to relate landscape variables to occurrence. Our model predicted that Smith's Longspurs may occur in valleys and foothills of the northeastern and southeastern mountains and in upland plateaus of the western mountains, and farther west than currently documented, over a predicted area no larger than 15% of the Brooks Range. With climate change, shrubs are expected to grow larger and denser, while soil moisture and moss cover are predicted to decrease. These changes may reduce Smith's Longspur habitat quality and limit distribution in the Brooks Range to poorly drained lowlands and alpine plateaus where sedge–shrub tundra is likely to persist. Conversely, northward advance of shrubs into sedge tundra may create suitable habitat, thus supporting a northward longspur distribution shift.

The Condor↗

USGS2018

Reproductive response of Arizona Grasshopper Sparrows to weather patterns and habitat structure

Avian species endemic to desert grasslands of North America contend with significant ecological challenges, including monsoonal rains, droughts, and variable temperatures. These birds have evolved physiological and behavioral means of coping with such extremes, but ongoing changes to temperature and precipitation patterns are affecting their breeding phenology, reproductive success, and population growth rates. We examined how seasonal and daily weather conditions and habitat structure were associated with the nest survival of Arizona Grasshopper Sparrows ( Ammodramus savannarum ammolegus ) in the semidesert and plains grasslands of southeastern Arizona, USA. The mean ± SE daily survival rate (DSR) of nests was 0.960 ± 0.006, corresponding to overall nest success of 46%. The previous season's precipitation, large rain events, and nest concealment were the most important factors explaining DSR. Grasshopper Sparrow nest survival decreased with a wetter previous growing season and with large rain events on previous days. Nests that were more concealed had lower survival rates. There was some evidence that nest survival was lower later in the nesting season. In addition, when nest concealment was included in models, there were positive but weak associations between other vegetation variables and DSR—nests with higher visual obstruction at the nest and nest plot scales, and nests that were farther from shrubs >2 m tall, showed higher survival rates. Predation was the major cause of nest failure, suggesting complex interactions among predation, precipitation, and nest concealment. Further, our findings suggest tradeoffs in the potential effects of future climate change on A. s. ammolegus . The increased frequency of extreme storm events predicted for the region may result in reduced nest survival of A. s. ammolegus , but, conversely, lower seasonal precipitation prior to nesting may positively influence nest survival.

Arizona↗

USGS2018

Interisland genetic structure of two endangered Hawaiian waterbirds: The Hawaiian Coot and Hawaiian Gallinule

Most of Hawaii's endemic avifauna are species of conservation concern. Some of Hawaii's endangered waterbirds, however, have increased in number as a result of intensive management of wetlands. To inform these conservation efforts, we examined interisland genetic structure and gene flow within 2 Hawaiian endemic waterbirds, the Hawaiian Coot ( Fulica alai ) and the Hawaiian subspecies of the Common Gallinule ( Gallinula galeata sandvicensis ), using microsatellite and mitochondrial loci. Hawaiian Coots and Hawaiian Gallinules occupy coastal wetlands and exhibit similar life history characteristics and generation times, although they may differ in dispersal propensity. Mark–resight data for Hawaiian Coot indicate interisland movements, whereas Hawaiian Gallinules are sedentary. Genetic diversity is partitioned across the landscape differently for Hawaiian Coots and Hawaiian Gallinules; patterns of variation are likely influenced by behavioral and ecological mechanisms. Hawaiian Coots exhibit low levels of structure at microsatellite loci ( F ST = 0.029) and high levels of gene flow among islands. Conversely, Hawaiian Gallinules are highly structured across marker types (microsatellite F ST = 0.205, mtDNA control region F ST = 0.370, mtDNA ND2 F ST = 0.087), with restricted recent gene flow. Patterns of gene flow have changed after the population declines in the early to mid-1900s. Gene flow estimates indicate historical dispersal from Kauai to Oahu in both species, while recent estimates show individual Hawaiian Coots dispersing from Oahu and restricted gene flow between islands for the Hawaiian Gallinule. Changes in gene flow through time suggest that patterns of dispersal may be an artifact of the availability of habitat, which may be indirectly associated with the synergistic influences of population density and wetland quality. Despite recent population size increases for both species, continued threats to Hawaiian waterbirds (i.e. nonnative mammalian predators and invasive plants, avian disease, altered hydrology, and saltwater inundation of freshwater wetlands) will likely require continued active management to maintain viable populations.

Hawaii↗

USGS2020

Giant Gartersnakes (Thamnophis gigas) exploit abundant non-native prey while maintaining their appetite for native anurans

The introductions of nonnative species can cause great change in the trophic dynamics of native species. Giant Gartersnakes, endemic predators in the Central Valley of California, are listed as threatened because of the conversion of their once vast wetland habitat to agriculture. Further contributing to this snake's changing ecology is the introduction of many nonnative prey species, resulting in a diet that is almost completely composed of nonnative species. In order to determine whether these snakes actively select their prey or simply consume what is abundant, we examined prey selection by adult Giant Gartersnakes in the context of what prey was available to each individual. Giant Gartersnakes selected a native anuran over nonnative anuran and fish species despite these nonnatives dominating the available species composition. These results contribute to understanding the mechanisms underlying Giant Gartersnake diets in the contemporary landscape and can lead to improved management of prey communities for Giant Gartersnakes and other native predators.

Herpetologica↗

USGS2006

Fens and floodplains of the temperate zone: Present status, threats, conservation and restoration

This Special Feature focuses on lowland fens and flood plains. In this introduction we discuss the most important mire-related terms, present status, threats and conservation and restoration attempts. Floodplains and especially lowland fens are rare and vulnerable ecosystems. They are highly threatened all over the world because of direct conversion to agricultural land and especially the lack of appropriate management and altered catchment hydrology. Finally we present a framework for the conservation and restoration of these ecosystems. This consists of (1) optimising abiotic conditions; (2) safeguarding propagule availability of the target species; (3) creating and maintaining conditions for (re)establishment of these species, and (4) appropriate management to keep the conditions suitable. ?? IAVS; Opulus Press.

Conference Paper↗

USGS2015

Deep-sea ostracods from the South Atlantic sector of the Southern ocean during the Last 370,000 years

We report changes of deep-sea ostracod fauna during the last 370,000 yr from the Ocean Drilling Program (ODP) Hole 704A in the South Atlantic sector of the Southern Ocean. The results show that faunal changes are coincident with glacial/interglacial-scale deep-water circulation changes, even though our dataset is relatively small and the waters are barren of ostracods until mid-MIS (Marine Isotope Stage) 5. Krithe and Poseidonamicus were dominant during the Holocene interglacial period and the latter part of MIS 5, when this site was under the influence of North Atlantic Deep Water (NADW). Conversely, Henryhowella and Legitimocythere were dominant during glacial periods, when this site was in the path of Circumpolar Deep Water (CPDW). Three new species (Aversovalva brandaoae, Poseidonamicus hisayoae, and Krithe mazziniae) are described herein. This is the first report of Quaternary glacial/interglacial scale deep-sea ostracod faunal changes in the Southern and South Atlantic Oceans, a key region for understanding Quaternary climate and deep-water circulation, although the paucity of Quaternary ostracods in this region necessitates further research. ?? 2009 The Paleontological Society.

Journal of Paleontology↗

USGS2002

How sedge meadow soils, microtopography, and vegetation respond to sedimentation

The expansion of urban and agricultural activities in watersheds of the Midwestern USA facilitates the conversion of species-rich sedge meadows to stands of Phalaris arundinacea and Typha spp. We document the role of sediment accumulation in this process based on field surveys of three sedge meadows dominated by Carex stricta , their adjacent Phalaris or Typha stands, and transitions from Carex to these invasive species. The complex microtopography of Carex tussocks facilitates the occurrence of other native species. Tussock surface area and species richness were positively correlated in two marshes (r 2 =0.57 and 0.41); on average, a 33-cm-tall tussock supported 7.6 species. Phalaris also grew in tussock form in wetter areas but did not support native species. We found an average of 10.5 Carex tussocks per 10-m transect, but only 3.5 Phalaris tussocks. Microtopographic relief, determined with a high-precision GPS, measured 11% greater in Carex meadows than Phalaris stands. Inflowing sediments reduced microtopographic variation and surface area for native species. We calculated a loss of one species per 1000 cm 2 of lost tussock surface area, and loss of 1.2 species for every 10-cm addition of sediment over the sedge meadow surface. Alluvium overlying the sedge meadow soil had a smaller proportion of organic matter content and higher dry bulk density than the buried histic materials. We conclude that sedimentation contributes to the loss of native species in remnant wetlands.

Wetlands↗

USGS2004

Changes in lagoonal marsh morphology at selected northeastern Atlantic coast sites of significance to migratory waterbirds

Five lagoonal salt marsh areas, ranging from 220 ha to 3,670 ha, were selected from Cape Cod, Massachusetts to the southern DelMarVa peninsula, Virginia, USA to examine the degree to which Spartina marsh area and microhabitats had changed from the early or mid- 1900s to recent periods. We chose areas based on their importance to migratory bird populations, agency concerns about marsh loss and sea-level rise, and availability of historic imagery. We georeferenced and processed aerial photographs from a variety of sources ranging from 1932 to 1994. Of particular interest were changes in total salt marsh area, tidal creeks, tidal flats, tidal and non-tidal ponds, and open water habitats. Nauset Marsh, within Cape Cod National Seashore, experienced an annual marsh loss of 0.40% (19% from 1947 to 1994) with most loss attributed to sand overwash and conversion to open water. At Forsythe National Wildlife Refuge in southern New Jersey, annual loss was 0.27% (17% from 1932 to 1995), with nearly equal attribution of loss to open water and tidal pond expansion. At Curlew Bay, Virginia, annual loss was 0.20% (9% from 1949 to 1994) and almost entirely due to perimeter erosion to open water. At Gull Marsh, Virginia, a site chosen because of known erosional losses, we recorded the highest annual loss rate, 0.67% per annum, again almost entirely due to erosional, perimeter loss. In contrast, at the southernmost site, Mockhorn Island Wildlife Management Area, Virginia, there was a net gain of 0.09% per annum (4% from 1949 to 1994), with tidal flats becoming increasingly vegetated. Habitat. implications for waterbirds are considerable; salt marsh specialists such as laughing gulls ( Larus atricilla ), Forster's terns ( Sterna forsteri ), black rail, ( Laterallus jamaicensis ), seaside sparrow ( Ammodramus maritimus ), and saltmarsh sharp-tailed sparrow ( Ammodramus caudacutus ) are particularly at risk if these trends continue, and all but the laughing gull are species of concern to state and federal managers.

Massachusetts, New Jersey, Virginia↗

USGS2008

Recent sedimentation patterns within the central Atchafalaya Basin, Louisiana

Sediment deposition and storage are important functions of forested bottomlands, yet documentation and interpretation of sedimentation processes in these systems remain incomplete. Our study was located in the central Atchafalaya Basin, Louisiana, a distributary of the Mississippi River and contains the largest contiguously forested riparian wetland in North America, which suffers from high sedimentation in some areas and hypoxia in others. We established 20 floodplain transects reflecting the distribution of depositional environments within the central Basin and monitored general and local sediment deposition patterns over a three-year period (2000-2003). Deposition rate, sediment texture, bulk density, and loss on ignition (LOI, percent organic material) were determined near or just above artificial markers (clay pads) located at each station per transect. Transect mean sedimentation rates ranged from about 2 to 42 mm/yr, mean percent organic material ranged from about 7% to 28%, mean percent sand (> 63 ??) ranged from about 5% to 44%, and bulk density varied from about 0.4 to 1.3. The sites were categorized into five statistically different clusters based on sedimentation rate; most of these could be characterized by a suite of parameters that included hydroperiod, source(s) of sediment-laden water, hydraulic connectivity, flow stagnation, and local geomorphic setting along transect (levee versus backswamp), which lead to distinct spatial sedimentation patterns. Sites with low elevation (long hydroperiod), high hydraulic connectivity to multiple sources of sediment-laden water, and hydraulic damming (flow stagnation) featured the highest amounts of sediment trapping; the converse in any of these factors typically diminished sediment trapping. Based on aerial extent of clusters, the study area potentially traps 6,720,000 Mg of sediment annually, of which, 820,000 Mg represent organic materials. Thus, the Atchafalaya Basin plays a substantial role in lowland sediment (and associated contaminant) storage, including the sequestration of carbon. Findings on local sedimentation patterns may aid in management of flow to control sediment deposition and reduce hypoxia. ?? 2008, The Society of Wetland Scientists.

Wetlands↗

USGS2008

Primary production and carrying capacity of former salt ponds after reconnection to San Francisco Bay

Over 6,110 ha of the commercial production salt ponds surrounding South San Francisco Bay, CA, have been decommissioned and reconnected to the bay, most as part of the largest wetlands restoration program in the western United States. These open water ponds are critical habitat for millions of birds annually and restoration program managers must determine the appropriate balance between retention of ponds versus re-conversion to tidal salt marsh, knowing that both are essential ecosystems for endangered bird species. Our study describes the ecological value of the new open water pond ecosystems as feeding habitats for birds. We used the oxygen rate of change method to determine ecosystem metabolic parameters from high resolution time-series of dissolved oxygen concentration. Areal gross primary production (8.17 g O 2 m −2 d −1 ) was roughly double the world’s most productive estuaries. High rates of phytoplankton photosynthesis were balanced by equally high rates of community respiration (8.25 g O 2 m −2 d −1 ). Metabolic equilibrium was delicately poised: sharp irradiance and temperature shifts triggered short term photosynthesis reduction resulting in oxygen depletion. We converted net primary production (NPP) into potential carrying capacity of the forage biota that support targeted pond waterbirds. NPP was processed through both a pelagic food web, resulting in forage biota for piscivorous birds and a benthic food web, resulting in forage biota for shorebirds and diving benthivores. Both food webs included efficient algal-based and inefficient detrital trophic pathways. The result of all primary production being routed through simple food webs was high potential forage production and energy supply to waterbirds, equivalent to 11–163 million planktivorous fish or 19–78 billion small estuarine clams within the 330-ha pond between May and October. Food quantity does not necessarily equal quality and these systems have the potential to produce toxic or inedible algae. Our study provides the first measurement of primary production in the open water ponds of San Francisco Bay and presents a novel approach for transforming primary production into forage production as a metric of an ecosystem’s energetic carrying capacity.

California↗

USGS2009

Identifying baldcypress-water tupelo regeneration classes in forested wetlands of the Atchafalaya Basin, Louisiana

Baldcypress-water tupelo (cypress-tupelo) swamps are critically important coastal forested wetlands found throughout the southeastern U.S. The long-term survival and sustainability of these swamp forests is unknown due to large-scale changes in hydrologic regimes that prevent natural regeneration following logging or mortality. We used NWI wetland maps and remotely sensed hydrologic data to map cypress-tupelo communities, surface water, and the extent and location of proposed regeneration condition classes for cypress-tupelo swamps in the Atchafalaya Basin, LA. Only 6,175 ha (5.8%) of the 106,227 ha of cypress-tupelo forest in the Lower Atchafalaya Basin Floodway was classified as capable of naturally regenerating. Over 23% (24,525 ha) of the forest area was mapped as unable to regenerate either naturally or artificially. The loss and conversion of nearly 25,000 ha of cypress-tupelo forest would have significant and long-lasting impacts on ecosystem services such as wildlife habitat for birds and Louisiana black bears. Given the landscape-scale changes in surface elevations and flooding depths and durations throughout southern Louisiana, similar conditions and impacts are likely applicable to all coastal cypress-tupelo forests in Louisiana. Better data on flooding during the growing season are needed to more accurately identify and refine the location and spatial extent of the regeneration condition classes.

Louisiana↗

USGS2011

Drought effect on selection of conservation reserve program grasslands by white-tailed deer on the Northern Great Plains

Limited information exists regarding summer resource selection of white-tailed deer (Odocoileus virginianus) in grassland regions of the Northern Great Plains. During summers 2005-2006, we analyzed habitat selection of adult female white-tailed deer in north-central South Dakota. We collected 1905 summer locations and used 21 and 30 home ranges during 2005 and 2006, respectively, to estimate habitat selection. Results indicated that selection occurred at the population (P < 0.001) and home range (P < 0.001) levels. Deer selected for Conservation Reserve Program grasslands and corn during both summers and shifted selection temporally within summer. Use of CRP grasslands occurred during early summer; 73.1 and 88.9% of locations in CRP were documented prior to 1 Jul. during 2005 and 2006, respectively. Conversely, selection for corn occurred during late summer; 86.0 and 68.4% of locations in corn were documented after 1 Jul. during 2005 and 2006, respectively. Additionally, deer selected for forested cover and rural development areas containing permanent water sources during extreme drought conditions during 2006. Deer likely selected for fields of CRP grasslands during early summer for cover and natural forages, such as clover (Trifolium sp.), prior to the period when agricultural crops become available. Drought conditions occurring in semiarid prairie grassland regions may reduce food and water availability and contribute to subsequent changes in deer habitat selection across the range of the species.

American Midland Naturalist↗