No full-text available
To read the full-text of this research,
you can request a copy directly from the authors.
Diet of Trachemys scripta (Red-eared Slider) and Graptemys geographica (Common Map Turtle) in an Urban Landscape
... The current hypothesis is that turtles become infected with N. chrysemydis, N. emyditoides, and N. pseudemydis by ingesting infected ostracods. This hypothesis is supported by the feeding habits of aquatic turtles, such as red-eared sliders, which consume large amounts of aquatic vegetation, sessile aquatic organisms, and detritus where ostracods reside (Lindeman and Barger, 2005;Ernst and Lovich, 2009;Thorp and Rogers, 2016;Stephens and Ryan, 2019). ...
... Although Na is non-essential for plants and found in low concentrations, this element is a limiting nutrient in herbivores and plays an important role in Na-K pumps required for osmoregulation (Kaspari, 2020;Filipiak et al., 2023). Red-eared sliders often feed on large quantities of plant materials and in turn may be Na limited in freshwater habitats with low levels of animal matter (Stephens and Ryan, 2019). All 4 species of acanthocephalans had higher concentrations of Na than of K, despite lower concentrations of Na than K in turtle hosts. ...
Turtle acanthocephalans in the genus Neoechinorhynchus have complex life cycles and are thought to involve an ostracod intermediate host and a turtle definitive host. For Neoechinorhynchus emydis, an additional snail paratenic host is part of its life cycle. However, how snails become infected and whether other species of Neoechinorhynchus can be found in snails remains unclear. This study was conducted to understand the survival, development, and host use of 4 species of turtle acanthocephalans (Neoechinorhynchus chrysemydis, N. emydis, Neoechinorhynchus emyditoides, and Neoechinorhynchus pseudemydis) in their intermediate, paratenic, and definitive hosts. Using eggs recovered from adult acanthocephalans from naturally infected turtle hosts in Oklahoma, experimental infections were conducted in 2 species of ostracods and 1 species of freshwater snail. Ionomes also were generated for these acanthocephalans and their turtle definitive hosts to better understand resource competition. Upon ingestion by ostracods, eggs of all 4 species of acanthocephalans hatched in both ostracod species. However, no further acanthocephalan development occurred in Cypridopsis sp. ostracods, whereas all 4 acanthocephalan species grew and developed into infective juveniles over 28-32 days in Physocypria sp. ostracods. Of the 4 species of acanthocephalans, N. emydis grew faster early in ostracods and was the only species to survive and establish in snail hosts. This finding was supported by the observation of proboscis remnants in the feces of snails that ingested ostracods infected with N. chrysemydis, N. emyditoides, and N. pseudemydis. In contrast, when snails were exposed to eggs of all 4 acanthocephalan species, eggs were passed in the feces, resulting in no infections. The overall ionomic composition of adult acanthocephalans and their turtle hosts suggested that the hosts and parasites share host resources. However, specific elemental differences indicated that turtle acanthocephalans can accumulate heavy metals at concentrations higher than those in their hosts. Results of this study support previous field observations and hypotheses that (1) Physocypria sp. ostracods serve as intermediate hosts for N. chrysemydis, N. emydis, N. emyditoides, and N. pseudemydis; (2) N. emydis uses snail paratenic hosts, but snails are a non-viable route of transmission to turtles for N. chrysemydis, N. emyditoides, and N. pseudemydis; and (3) as adults, these 4 acanthocephalan species utilize their turtle definitive hosts similarly in terms of ionomic composition. This work challenges the traditional view of the acanthocephalan life cycle and sets the stage for future hypotheses.
... Several dietary studies assessed the stomach and/or intestine content of Slider populations, both from the native range (Pierce, 1992;Dreslik, 1999;Stephens and Ryan, 2019) and from the non-native range (Prevot-Julliard et al., 2007;Outerbridge, 2008;Lee and Park, 2010;Pérez-Santigosa et al., 2011;Wang et al., 2013;Works and Olson, 2018). These identify both native and non-native populations as omnivorous, with different life stages having different diets; for example, smaller Sliders are more carnivorous, whereas adults are more herbivorous. ...
Pond Sliders, Trachemys scripta, are among the widest-spread animal species outside their native range, and habitat suitability modelling has demonstrated that the current range of this species can expand even further. This species is also widely reported in Europe with successful reproduction being reported mainly from southern locations, though increasingly from more northern populations, e.g., Germany. Nonnative Trachemys scripta impact native species and ecosystems, e.g., they can displace native turtle species and are known to harbour pathogens and parasites. Surprisingly little attention has been given to their impact on freshwater ecosystems, and additionally, dietary studies are few in number and do not implement a methodology that allows identification of all prey taxa. Here, we report how a live duckling (Anas platyrhynchos) was predated on by a large adult Trachemys scripta. The event, where the turtle grabbed the duckling from the water surface and submerged underwater, only took several seconds. Although vertebrate prey has been identified in stomach/intestine samples of Trachemys scripta, the general explanation has been this species’ scavenging behaviour. Our report provides an alternative explanation, namely predation of live prey that has not been frequently observed due to the speed of such events. Therefore, from a biological invasion perspective, the effect of non-native Trachemys scripta populations on native vertebrate fauna may be underestimated. We argue that to better understand the occurrence, frequency and diversity of prey in future dietary studies of Trachemys scripta (and other taxa), genetic techniques should be applied.
The Rio Grande cooter (Pseudemys gorzugi) is an imperiled freshwater turtle native to the southwestern United States and northeastern Mexico. Previous studies investigating P. gorzugi diet have focused on the population occupying the Black River drainage in southeastern New Mexico, while Texas populations have remained unexamined. During the summer and fall of 2020, we studied the dietary habits of P. gorzugi and the syntopic red-eared slider (Trachemys scripta elegans) at San Felipe Creek, Texas, USA using fecal content and stable isotope analyses. We also compared the isotopic niches of these 2 co-occurring turtle species. Filamentous algae were, volumetrically, the most important food item for male, female, and juvenile P. gorzugi. Stable isotope mixing models indicated that lotic and lentic filamentous algae had the greatest proportional contribution to P. gorzugi and T. s. elegans diets, respectively. Stable isotope dietary mixing models also indicate T. s. elegans had a more carnivorous diet, composed mostly of red-rimmed melania (Melanoides tuberculata) and red swamp crayfish (Procambarus clarkii). Carnivory in this species was further supported by enriched δ15N values and higher trophic position estimates. Pseudemys gorzugi and T. s. elegans had δ13C and δ15N signatures that significantly differed, and the 2 species showed little overlap in isotopic niche space, suggesting a low likelihood of intense resource competition. Our results demonstrate that the diet of P. gorzugi, and the isotopic niche overlap between P. gorzugi and T. s. elegans at San Felipe Creek differ from that in the Black River drainage of New Mexico. The information provided here contributes toward a more complete understanding of P. gorzugi ecology, is useful for identifying suitable habitat worthy of conservation, and can help guide the development of feeding regimes for captive assurance colonies.
Setiadi AE, Rahayu HM. 2021. Reptiles in the Pontianak and Kubu Raya Residental Area, West Kalimantan, Indonesia. Biodiversitas 22: 2763-2770. The increase in population is directly proportional to housing needs. Expansion of residential areas can threaten the diversity of reptiles in West Kalimantan. This study aims to inventory and identify the diversity of reptiles in residential areas in Pontianak and Kubu Raya, West Kalimantan province, Indonesia. This research gives a better understanding of reptilian urban species to support monitoring and evaluation of biodiversity in West Kalimantan. This research uses the descriptive exploratory method. Four study areas were selected based on a proportion of impervious surfaces. Data collection used the VES (Visual Encounter Survey). Identification refers to Reptile field guides and identification books. The data were analyzed descriptively qualitatively, the level reptile diversity was analyzed using the Shannon Diversity Index, and the similarities of reptiles between the residential area in Pontianak and Kubu Raya were assessed using the Jaccard similarity coefficient. The results showed, from 50 individual reptiles found in Pontianak and Kubu Raya, there were 13 reptile species from the order Squamata and the order Testudines. The Shannon-Wiener Diversity Index of 2.26 and Jaccard similarity coefficient 0.384, indicating that the level of diversity of reptile species in the two study areas is classified as moderate.
The world's population is concentrated in urban areas. This change in demography has brought landscape transformations that have a number of documented effects on stream ecosystems. The most consistent and pervasive effect is an increase in impervious surface cover within urban catchments, which alters the hydrology and geomorphology of streams. This results in predictable changes in stream habitat. In addition to imperviousness, runoff from urbanized surfaces as well as municipal and industrial discharges result in increased loading of nutrients, metals, pesticides, and other contaminants to streams. These changes result in consistent declines in the richness of algal, invertebrate, and fish communities in urban streams. Although understudied in urban streams, ecosystem processes are also affected by urbanization. Urban streams represent opportunities for ecologists interested in studying disturbance and contributing to more effective landscape management.
Alterations of flow regimen, pollution, and introductions of exotic species have significantly altered the composition of invertebrates in many river systems throughout the world. How these alterations affect the diet of higher level predators is not well understood. We studied the diet of the Northern Map Turtle (Graptemys geographica) in the dam-regulated Susquehanna River in north-central Maryland. Northern Map Turtles are a relatively large, top-order predator that is legally endangered in the state and is impacted by commercial collecting elsewhere. Gastropods, trichopteran larvae, and invasive Corbicula sp. predominated across diet samples. Marked sexual and size-related differences occurred. Adult male G. geographica fed primarily on a group of small gastropod species (Planorbidae, Hydrobiidae, Physidae), trichopterans, and Corbicula, while adult females fed primarily on pleurocerid snails. There was virtually no overlap in the diets of the two sexes of G. geographica. This is of special conservation concern because two different groups of prey are needed in order to support this population of Northern Map Turtles, and many North American pleurocerid gastropod species are highly endangered and also threatened by hydroelectric activity. Our results are consistent with reports of other Map Turtle populations before the invasion of Zebra Mussels (Dreissena sp.), which often result in a sharp change in diet. Zebra Mussels have already been documented immediately upstream of our study site, so impacts from this invasive species may become apparent in the near future.
A dietary change occurs from youth to maturity in the turtle Pseudemys scripta in South Carolina. Juveniles in their first year of growth were primarily carnivorous whereas adults were largely herbivorous. The shift from a carnivorous to a herbivorous diet occurred over the course of one summer. A positive correlation between the calcium content of the shell and size of the turtle is demonstrated. The food of juveniles contained a significantly higher percentage of calcium than the food of the adults.
In order to effectively manage urban habitats, it is important to incorporate the spatial ecology and habitat use of the species utilizing them. Our previous studies have shown that the distribution of upland habitats surrounding a highly urbanized wetland habitat, the Central Canal (Indianapolis, IN, USA) influences the distribution of map turtles (Graptemys geographica) and red-eared sliders (Trachemys scripta) during both the active season and hibernation. In this study we detail the movements and habitat use of another prominent member of the Central Canal turtle assemblage, the common snapping turtle, Chelydra serpentina. We find the same major upland habitat associations for C. serpentina as for G. geographica and T. scripta, despite major differences in their activity (e.g., C. serpentina do not regularly engage in aerial basking). These results reinforce the importance of recognizing the connection between aquatic and surrounding terrestrial habitats, especially in urban ecosystems.
In urbanized landscapes, golf course ponds may provide the only remaining habitat for semi-aquatic animals. Eastern Mud Turtles (Kinosternon subrubrum), which rely heavily on both aquatic and terrestrial habitats, may face challenges on golf courses, which typically have significantly modified and fragmented landscapes. We conducted a radio-telemetric study of 11 mud turtles inhabiting a golf course pond in the western Piedmont of North Carolina to investigate their terrestrial activity and habitat selection in a fragmented landscape. Most turtles moved to terrestrial habitats in late summer and emigrated a mean distance ( SE) of 187.2 67.4 m and moved a mean straight line distance ( SE) of 119.3 47.4 m from the pond. We determined habitat selection using logistic regression to compare turtle locations with random locations and found that mud turtles selected forested habitats with moderate canopy cover and no grass. Mud turtles also selected habitat containing herbaceous vegetation and woody debris as overwintering locations. Mud turtles did not select heavily disturbed habitats with limited canopy cover and pavement or cut grass associated with fairways, roughs, and residential lawns. Overall, our study suggests that maintaining relatively undisturbed forested habitat within fragmented urban landscapes, such as those found on golf courses, may allow for the persistence of these semi-aquatic turtles. Information from this study can be used to better understand critical upland habitat requirements of other semi-aquatic species inhabiting fragmented landscapes and aid in the implementation of habitat management plans.
Road mortality has the potential to alter the structure of turtle populations because turtle populations are highly sensitive to additive sources of adult mortality. To address the issue, we captured painted turtles ( Chrysemys picta; n = 174) and snapping turtles ( Chelydra serpentina; n = 56) in 18 wetlands surrounded by low road density (≤1.5 km roads/km2 of landscape) and 17 wetlands surrounded by high road density (>1.5 km/km2) in central New York in 2002. High road density was associated with male-biased sex ratios in painted turtles (74% vs. 54% males; p = 0.01) and snapping turtles (95% vs. 74% males; p = 0.08), whereas turtle morphology and abundance were not associated with road density. Disproportionate road mortality of females on nesting migrations is the most likely cause of skewed sex ratios.
Resumen: La mortalidad en caminos tiene el potencial de alterar a las poblaciones de tortugas porque son relativamente sensibles a causas aditivas de mortalidad de adultos. Para abordar este tema, en 2002 capturamos Chrysemys picta (n = 174) y Chelydra serpentina (n = 56) en 18 humedales con baja densidad de caminos (≤1.5 km caminos/km2 de paisaje) y en 17 humedales con alta densidad de caminos (>1.5 km caminos/km2 de paisaje) en New York central. La densidad alta de caminos se asoció con proporciones de sexo sesgadas hacia machos en Chrysemys picta (74% vs. 54% machos; p = 0.01) y en Chelydra serpentina (95% vs. 74% machos; p = 0.08), mientras que la morfología y abundancia de tortugas no estuvieron asociadas con la densidad de caminos. La excesiva mortalidad de hembras en migración reproductiva es la causa más probable del sesgo en las proporciones de sexo.
Stomachs of the freshwater turtle Trionyx muticus mainly contained various invertebrates (primarily insects), fruits and fish carrion. The diet of males was more diverse and was significantly different from that of females. About 71% by volume of the prey of females was aquatic items (especially Hydropsyche larvae), whereas 67% of the prey of males was terrestrial items. No significant relationship could be found between comparisons of prey size and turtle size and of prey size and sex of turtle. Females forage primarly in stable microhabitats in deep water whereas males forage at the shallower interface between terrestrial and aquatic environments.-from Authors
Urban environments pose special challenges to flora, including altered disturbance regimes, habitat fragmentation, and increased opportunity for invasion by non-native species. In addition, urban natural area represents most people's contact with nature, given the majority of the world's population currently live in cities. We used coefficients of conservatism (C-values), a system that ranks species based on perceived fidelity to remnant native plant communities that retain ecological integrity, to quantify habitat quality of 14 sites covering 850 ha within the city of Indianapolis, Indiana, in the Midwestern United States. All sites contained significant natural area and were inventoried via intensive complete censuses throughout one or two growing seasons within the last 15 years. Mean C-values for five sites were high, especially when compared to values reported for the highest quality preserves in central Indiana. However, for most sites the difference in mean C-value with and without non-natives was rather high, meaning that natural quality is likely to have been compromised by the presence of non-natives. Sites receiving the highest levels of stewardship and those with the least public access via trails had the highest mean native C-values. A total of 34 invasive non-native species were found across all 14 sites. Most were woody species. Mean C-value over all sites was significantly negatively correlated with the number of non-natives present, especially those considered invasive. These results demonstrate for the Indianapolis area, and likely other urbanized OPEN ACCESS Diversity 2011, 4 612 Midwestern cities, remnant natural areas can retain high ecological value, especially if they receive regular environmental stewardship.
The term ''urban stream syndrome'' describes the consistently observed ecological degra-dation of streams draining urban land. This paper reviews recent literature to describe symptoms of the syndrome, explores mechanisms driving the syndrome, and identifies appropriate goals and methods for ecological restoration of urban streams. Symptoms of the urban stream syndrome include a flashier hy-drograph, elevated concentrations of nutrients and contaminants, altered channel morphology, and reduced biotic richness, with increased dominance of tolerant species. More research is needed before generaliza-tions can be made about urban effects on stream ecosystem processes, but reduced nutrient uptake has been consistently reported. The mechanisms driving the syndrome are complex and interactive, but most impacts can be ascribed to a few major large-scale sources, primarily urban stormwater runoff delivered to streams by hydraulically efficient drainage systems. Other stressors, such as combined or sanitary sewer overflows, wastewater treatment plant effluents, and legacy pollutants (long-lived pollutants from earlier land uses) can obscure the effects of stormwater runoff. Most research on urban impacts to streams has concentrated on correlations between instream ecological metrics and total catchment imperviousness. Recent research shows that some of the variance in such relationships can be explained by the distance between the stream reach and urban land, or by the hydraulic efficiency of stormwater drainage. The mech-anisms behind such patterns require experimentation at the catchment scale to identify the best management approaches to conservation and restoration of streams in urban catchments. Remediation of stormwater impacts is most likely to be achieved through widespread application of innovative approaches to drainage design. Because humans dominate urban ecosystems, research on urban stream ecology will require a broadening of stream ecological research to integrate with social, behavioral, and economic research.
We investigated the demography of a common aquatic turtle (Chrysemys picta) along a gradient of urbanization in southeastern New Hampshire. Using a geographic information system and live trapping of turtles, we compared the proportion of males, the proportion of adults, and the relative abundance of turtles in 37 ponds. We used satellite images, aerial photographs, and field visits to describe pond-specific features and habitat composition up to 2000 m from the perimeter of each pond. The proportion of males was positively associated with the percentage of forest cover within 500 m, greater road density within 100 m, and an index of predator activity at a pond. The proportion of adults in a population was associated with road density within 250 m of the pond and the percentage of the pond perimeter that was forested. Abnormal population structures associated with greater road densities did not necessarily result in lower abundances of turtles in ponds. Turtle abundance increased as the distance to neighboring wetlands decreased and the amount of nesting habitat near pond edges increased. Pond-specific features also affected turtle abundance where populations were larger in ponds with organic substrates and abundant coverage by shoreline vegetation than in ponds lacking these features. Few turtles were encountered in ponds with an abundance of herbaceous emergent vegetation, and fewer turtles were captured during a summer with abundant precipitation. Suburban and urban developments, with dense road networks and abundant populations of generalist predators (especially the raccoon, Procyon lotor), can alter the structure of aquatic turtle populations. Although these alterations may not result in immediate changes in turtle abundance within a specific population, we suspect that the reduction in recruitment caused by habitat alterations will eventually reduce or eliminate local populations. Even though there are life-history differences among species of turtles, our results may provide new insight into the causes of recent declines of other turtles.Resumen: Investigamos la demografía de una tortuga acuática común (Chrysemys picta) a lo largo de un gradiente de urbanización en el sur de New Hampshire. Por medio de un sistema de información geográfica y la captura de tortugas vivas, comparamos la proporción de machos, proporción de adultos y la abundancia relativa de tortugas en 37 charcas. Utilizamos imágenes de satélite, fotografías aéreas y visitas de campo para describir características específicas de cada charca y la composición del hábitat hasta 2000 m del perímetro de cada charca. La proporción de machos se asoció positivamente con el porcentaje de cobertura forestal hasta 500 m, mayor densidad de caminos hasta 100 m y un índice de actividad de depredador en una charca. La proporción de adultos en una población se asoció con la densidad de caminos hasta 250 m de la charca y el porcentaje arbolado del perímetro de la charca. Estructuras poblacionales anormales asociadas con mayores densidades de caminos no resultaron necesariamente en menor abundancia de tortugas en las charcas. La abundancia de tortugas incrementó a medida que disminuía la distancia a humedales vecinos y aumentaba la cantidad de hábitat para anidar cerca de los bordes de las charcas. Las características específicas de las charcas también afectaron a la abundancia de tortugas donde las poblaciones fueron mayores en charcas con sustratos orgánicos y abundante cobertura de vegetación de borde que en charcas sin estas características. Encontramos pocas tortugas en charcas con abundancia de vegetación herbácea emergente, y capturamos menos tortugas durante un verano con abundante precipitación. Desarrollos urbanos y suburbanos, con densas redes de caminos y poblaciones abundantes de depredadores generalistas (especialmente el mapache, Procyon lotor), pueden alterar la estructura de las poblaciones de tortugas acuáticas. Aunque estas alteraciones pueden no resultar en cambios inmediatos en la abundancia de tortugas en una población específica, sospechamos que la reducción de reclutamiento causada por alteraciones de hábitat eventualmente reducirá o eliminará poblaciones locales. Aunque hay diferencias en la historia de vida entre especies de tortugas, nuestros resultados pueden proporcionar una nueva visión de las causas de declinaciones recientes de otras tortugas.
Road mortality has been implicated as a significant demographic force in turtles, particularly for females, which are killed disproportionately on overland nesting movements. Moreover, the United States' road network has expanded dramatically over the last century. We therefore predicted that historical trends in sex ratios of turtle populations would be male biased. To test this prediction, we synthesized published estimates of population-level sex ratios in freshwater and terrestrial turtles in the United States (165 estimates for 36 species, published 1928–2003). Our analysis suggests that the proportion of males in populations has increased linearly (p= 0.001); the trend in male bias is synchronized with the expansion of the surfaced portion of the road network since 1930; sex ratios became more male biased in states with higher densities of roads; and populations have become more male biased in aquatic species, in which movement differentials between males and females are greatest, and are least biased in semiaquatic and terrestrial species, in which overland movements are more comparable between sexes. Our results suggest an ongoing depletion of breeding females from wild turtle populations over the last century because of many factors, including, and perhaps chiefly, road mortality.
Studies were carried out in eight woodland water bodies that are situated in an urbanised area of Southern Poland (Upper Silesia).
The aim of this study was to determine the influence of auto- and allochthonous plant detritus and exposure to sunlight on
the structure of snail communities in woodland ponds. Among some physico-chemical water parameters, pH influenced the occurrence
of snails, whereas sunlight caused an increase in diversity of the snail communities. In the total snail collection, 72.1%
of specimens were gathered in sun-exposed sites. By the same degree of insolation more preferred by snails were the sites
with allochthonic detritus. The snail fauna of subsidence ponds located inside a forest area differs from those occurring
in urban agglomerations. The most conspicuous difference is the high numbers in three woodland ponds of Hippeutis complanatus (L.), which is rare in this area.
Key wordssubsidence ponds-leaf litter-plant detritus
Our study focuses on the spatial ecology and seasonal habitat use of two aquatic turtles in order to understand the manner
in which upland habitat use by humans shapes the aquatic activity, movement, and habitat selection of these species in an
urban setting. We used radiotelemetry to follow 15 female Graptemys geographica (common map turtle) and each of ten male and female Trachemys scripta (red-eared slider) living in a man-made canal within a highly urbanized region of Indianapolis, IN, USA. During the active
season (between May and September) of 2002, we located 33 of the 35 individuals a total of 934 times and determined the total
range of activity, mean movement, and daily movement for each individuals. We also analyzed turtle locations relative to the
upland habitat types (commercial, residential, river, road, woodlot, and open) surrounding the canal and determined that the
turtles spent a disproportionate amount of time in woodland and commercial habitats and avoided the road-associated portions
of the canal. We also located 21 of the turtles during hibernation (February 2003), and determined that an even greater proportion
of individuals hibernated in woodland-bordered portions of the canal. Our results clearly indicate that turtle habitat selection
is influenced by human activities; sound conservation and management of turtle populations in urban habitats will require
the incorporation of spatial ecology and habitat use data.
Theory predicts that small populations may be driven to extinction by random fluctuations in demography and loss of genetic diversity through drift. However, population size is a poor predictor of extinction in large carnivores inhabiting protected areas. Conflict with people on reserve borders is the major cause of mortality in such populations, so that border areas represent population sinks. The species most likely to disappear from small reserves are those that range widely-and are therefore most exposed to threats on reserve borders-irrespective of population size. Conservation efforts that combat only stochastic processes are therefore unlikely to avert extinction.
Throughout the past several years there has been an increasing concern to reduce the pollutants within urban stormwater discharges, particularly combined sewer overflows (CSOs). The majority of the research on CSOs has focused on physical, chemical, and some biological components. This preliminary study investigated the occurrence of two pathogenic protozoa, Cryptosporidium and Giardia, in an urban stream during dry weather compared to their occurrence in a combined sewer overflow (CSO) end-of-pipe discharge to determine the loading potential and the potential human health impacts. Cryptosporidium oocysts and Giardia cysts were commonly observed in the urban stream during dry weather conditions, with concentrations of 5-105 oocysts/100L and 13-6,579 cysts/100L respectively. The CSO end-of-pipe samples during wet weather conditions discharged Cryptosporidium and Giardia at high levels, 250-40,000 oocysts/100L and 9,000-283,000 cysts/100L respectively. This preliminary study suggests that CSOs may significantly contribute to the load of Cryptosporidium and Giardia in ambient waters and source waters utilized for recreational use and potable water. However, further investigation will be needed to determine and characterize the full effect of this apparent loading source.
Although urbanization has contributed to wildlife population declines, urban ditches may present some of the last remaining refugia in expanding cities where turtles have persisted. To determine effective and easy-to-implement conservation measures, it is crucial to better understand the ecology of these urban turtle populations. Here, we assessed the influence of six easy-to-understand ditch characteristics on turtle abundance and richness using generalized linear mixed models. We based our study on capture and habitat data collected from May to August of 2011 and 2012, in seven ditches of Jonesboro, Craighead County, Arkansas, USA. Over these two years, we captured 452 turtles of six different species. Abundance and species richness were higher in ditches that were wider, longer, deeper, and had a wider buffer zone than ditches without these characteristics. No other variables (e.g., substrate type) were associated with variation in abundance or richness. Our results highlight the importance of habitat size for the persistence of turtle populations. Although other factors (e.g., water quality, food abundance) might be more ecologically relevant to urban turtles, ditch dimensions, being easy to manipulate, should be strongly considered when building or modifying a ditch system to minimize impact on turtle populations.
The diet of red-eared turtle shifted gradually from insect to plant material with increasing plastron length, and paralleled a habitat shift from feeding sites in shallow to deep water. Basking perches used by small turtles were narrower, more steeply sloped, and located in shallower water than those used by large turtles.-from Author
Sternotherus odoratus is an omnivorous turtle inhabiting shallow littoral zones of lakes and swamps in the eastern United States. Previous studies have quantified the diet of this turtle, but few have addressed seasonal and sexual differences. Stomach and fecal samples were collected from June through October 1998. Although males and females consumed similar taxa, there were monthly dietary differences likely, in part, because of sexual differences in peak activity and reproductive conditions. Patterns of consumption suggest that Stinkpots are omnivorous but show some dietary preferences.
A review of 108 papers on food habits of fishes, amphibians and reptiles in eastern United States points to the importance of crawfishes in the diet of some of these animals. Knowledge of the productivity and reproductive potential of crawfishes is given along with brief notes on each of the twelve most important species indicated in the food habits studies reviewed. The need for additional work on crawfishes in order that they be utilized to fullest advantage in wildlife management is stressed.
Three species of map turtle, Graptemys geographica, G. ouachitensis and G. pseudogeographica, inhabit the Mississippi River near Stoddard, Vernon Co., Wisconsin. Adult females of all three species are of similar size and are distinctly larger than males. One species, G. geographica, has a notably wider head than the other two. Quantitative analysis of fresh stomach contents of 113 adult females, qualitative analysis of 74 others and feeding observations confirm that the three species use different foods and feeding strategies. Graptemys geographica is a carnivore specializing on mollusks. Graptemys ouachitensis is an omnivore, but specializes in surface feeding. Graptemys pseudogeographica is a general omnivore overlapping the other two species both in food and feeding areas. Graptemys geographica seems to be limited by food availability. Graptemys ouachitensis represents 66% of the Graptemys in the study area and may be best at exploiting an apparently unlimited food resource of aquatic vegetation and insect larvae. In Arkansas, G. pseudogeographica is a mollusk specialist, possibly due to lack of competition from G. geographica and competition from the ubiquitous generalist, Pseudemys scripta, and the strict vegetarian, Pseudernys concinna.
Annual and seasonal movement patterns of map turtles were determined along 6600 m of the Raystown Branch of the Juniata River, Pennsylvania, over 5 years. Annual movement patterns included: (1) late spring and summer movement, primarily by males, upstream from a deep, slow area and return downstream to it in late summer; (2) late spring downstream movement, mainly by males, from the deep, slow area and upstream return to it in late summer; and (3) confinement to small areas along the river. High water appeared to inhibit normal upstream movement and enhance downstream movement. Movement of juveniles was mainly downstream and that of gravid females upstream; movement patterns of most females were unclear. Males, females, and juveniles showed no significant differences between distances between successive captures within years. Several long distance movements over short time spans were recorded; the highest was 1457.5 m/day. Over the years, range lengths of males were significantly greater than those of females.
There is a limited understanding of the lotic macroinvertebrate fauna of West Africa, although many watercourses are heavily impacted. Macroinvertebrates were sampled from a stream running through Accra, the capital of Ghana, to provide information on the nature of these communities and their response to pollution. The physicochemical pollution gradient in the stream was reflected in the macroinvertebrate community, which showed a similar response to that observed in well studied temperate areas. Heavily polluted sites within the city supported a poor fauna and were dominated by tolerant taxa, such as the Chironomidae. The success of the macroinvertebrate fauna in revealing the pollution gradient and discriminating between sites suggest that there is potential for biological monitoring in such situations.
The fall-winter food habits of the Texas river cooter (Pseudemys texana) were investigated at Spring Lake, Hays County, Texas, by examination of stomach contents. Samples were collected from 33 live turtles by flushing stomach contents with water (Fields et al., 2000). Four aquatic macrophytes composed 91.6% of the diet. Aquatic macrophyte availability at Spring Lake was estimated using the Daubenmire technique (Daubenmire and Daubenmire, 1968) and compared to occurrence in the diet to assess selectivity in foraging. Cooters actively selected Carolina fanwort (Cabomba caroliniana), a plant low in fiber and high in total digestible nutrients. Hydrilla (Hydrilla verticilata), an invasive exotic aquatic plant, was an important food item due to the large amount present in the lake.
Basking is common in emydid turtles and is generally accepted to be a ther- moregulatory behavior. In 2004, we quantifi ed and described the basking behavior of turtles in the Central Canal of Indianapolis. This canal system fl ows through an urban landscape that is dominated by fragmented woodlots, residential areas, and commer- cial areas. We observed that basking turtles exhibited variable basking behavior, with spatial and temporal shifts in basking behavior from east-facing banks in the morn- ing to west-facing banks in the afternoon. Turtles in the Central Canal are subject to frequent disturbance, which altered basking behavior. Many turtles forewent aerial basking on emergent substrates for aquatic basking on vegetation mats, which main- tained warmer and more consistent temperatures than either emergent substrates or the surrounding water. Living in an intensively managed urban habitat, turtles in the Central Canal are susceptible to frequent anthropogenic perturbations, and future man- agement should consider the life history and ecology of urban turtle populations
We studied turtle populations inhabiting a canal and a lake (both man-made) within a heavily disturbed, urban setting. Six aquatic and semi-aquatic turtle species were collected in both habitats: spiny softshell turtle (Apolone spinifera), painted turtle (Chrysemys picta), common snapping turtle (Chelydra serpentina), common map turtle (Graptemys geographica), common musk turtle (Sternotherus odoratus) and red-eared slider (Trachemys scripta). While G. geographica was the most common species in the canal habitat, T. scripta was most common in the lake habitat. We describe patterns of sexual size dimorphism and sex ratios for the three most abundant species (G. geographica, T. scripta and S. odoratus). We discuss our data in light of problems facing turtle assemblages in urban settings.
Abstract Benthic macroinvertebrates were sampled from four sites on upland streams in the Wentworth Falls area of the Blue Mountains, NSW. One site received effluent from a sewage treatment plant and the others were reference sites. Five replicate collections were taken from each site on four occasions at intervals of 3 months. Macroinvertebrate community data were analysed using univariate (ANOVA) and multivariate (NMDS) techniques and comparisons were made between analyses at different levels of taxonomic aggregation and using different methods of data transformation. Similar patterns were observed at both species and family levels, and even the order level showed a clear community response to effluent input. Binary (presence/ absence) data provided similar results to quantitative data for the species and family levels. However, when binary data were used at the order level, the distinctions between the reference sites became blurred. We discuss the implications of these findings for environmental monitoring.
The diet of the Common Map Turtle (Graptemys geographica) was studied in Lake Erie habitats associated with a Pennsylvania sandspit peninsula. Three taxa predominated in fecal samples: trichopteran larvae (principally leptocerids), gastropods, and Zebra and Quagga Mussels (Dreissena spp.). Pronounced sexual and size-related differences occurred for these taxa, as adult males fed primarily on trichopterans and snails, while the larger females fed almost exclusively on Dreissena spp., with prevalence of Dreissena spp. increasing with body size. Dietary data from habitats lacking invasive mollusks suggest that the overall reliance on mollusks in the diet may have increased since the invasion of Lake Erie by Dreissena spp. Results are similar to earlier reports concerning the effect of invasive Asian Clams (Corbicula spp.) on decreasing dietary diversity in females of many populations of the four species of Graptemys that have mollusk-adapted mesocephalic females.
The exponential increase in population has fueled a significant demographic shift: 60% of the Earth's population will live in urban areas by 2030. While this population growth is significant in its magnitude, the ecological footprint of natural resource consumption and use required to sustain urban populations is even greater. The land use and cover changes accompanying urbanization (increasing human habitation coupled with resource consumption and extensive landscape modification) impacts natural ecosystems at multiple spatial scales. Because they generally occupy lower landscape positions and are linked to other ecosystems through hydrologic connections, the cascading effects of habitat alteration on watershed hydrology and nutrient cycling are particularly detrimental to wetland ecosystems. I reviewed literature relevant to these effects of urbanization on the structure and function of forested wetlands. Hydrologic changes caused by habitat fragmentation generally reduce species richness and abundance of plants, macroinvertebrates, amphibians, and birds with greater numbers of invasives and exotics. Reduction in soil saturation and lowered water tables result in greater nitrogen mineralization and nitrification in urban wetlands with higher probability of NO–
3 export from the watershed. Depressional forested wetlands in urban areas can function as important sinks for sediments, nutrients, and metals. As urban ecosystems become the predominant human condition, there is a critical need for data specific to urban forested wetlands in order to better understand the role of these ecosystems on the landscape.
The effect of sample size and species diversity on a variety of similarity indices is explored. Real values of a similarity index must be evaluated relative to the expected maximum value of that index, which is the value obtained for samples randomly drawn from the same universe, with the diversity and sample sizes of the real samples. It is shown that these expected maxima differ from the theoretical maxima, the values obtained for two identical samples, and that the relationship between expected and theoretical maxima depends on sample size and on species diversity in all cases, without exception. In all cases but one (the Morisita index) the expected maxima depend strongly to fairly strongly on sample size and diversity. For some of the more useful indices empirical equations are given to calculate the expected maximum value of the indices to which the observed values can be related at any combination of sample sizes. It is recommended that the Morisita index be used whenever possible to avoid the complex dealings with effects of sample size and diversity; however, when previous logarithmic transformation of the data is required, which often may be the case, the Morisita-Horn or the Renkonen indices are recommended.
We investigated predation of simulated turtle nests in an effort to understand how land-use patterns and the availability of nesting habitat may affect turtle recruitment in a region where human populations and associated development are increasing. Simulated nests were patterned after those created by painted turtles (Chrysemys picta), a common aquatic turtle in our study area, and distributed in four patterns (clustered and near pond, scattered and near pond, clustered and far from pond, and scattered and far from pond) around 36 ponds. Landscape composition (500–2000 m from pond perimeters) and habitats surrounding pond edges (an area extending 250 m from the shore of each pond) were then compared with rates of predation at each pond. Nest-site characteristics also were compared to the fate of individual nests. Landscape composition and habitats surrounding ponds apparently had little influence on predation rates. Nest distribution and the immediate habitat features associated with each nest did affect vulnerability to predation. Clumped nests were preyed upon at a higher rate than scattered nests, and nests close to ponds (within 50 m) were more vulnerable to predators than those created far (100–150 m) from a pond. Counter to our expectations, proximity to edge habitats (other than the shore of a pond) reduced the probability that a nest would be detected by predators. Also, nests placed near roads and suburban lawns had a reduced likelihood of predation whereas those placed in agricultural areas or disturbed sites had a greater probability of being preyed upon. Our results suggest that predation of simulated turtle nests may be a consequence of their distribution and location relative to the foraging activities of common nest predators, especially raccoons (Procyon lotor). Efforts to enhance recruitment among declining populations of turtles should consider the abundance and distribution of nesting habitat. Providing additional nesting sites away from predator foraging habitats may reduce nest predation and increase the recruitment of hatchlings into a population.
South Africa’s freshwater quality and quantity is declining and consequently impacting on the ecological health of these ecosystems, due to increased agricultural, urban and industrial developments. The River Health Programme (RHP) was designed for monitoring and assessing the ecological health of freshwater ecosystems in South Africa, in order to effectively manage these aquatic resources. The RHP utilises biological indicators such as in-stream biota as a structured and sensitive tool for assessing ecosystem health. Although the RHP has been widely implemented across South Africa, no attempts have been made to explore microbial ecology as a tool that could be included as one of the RHP indices. This study used selected microbial responses and water physico-chemical parameters to assess the current water quality status of the Buffalo River. This study showed that water quality impairments compounded in the urban regions of King William’s Town and Zwelitsha and also downstream of the Bridle Drift Dam. The results also showed that the lower and the upper catchments of the Buffalo River were not significantly different in terms of water physico-chemistry and microbiology, as indicated by low stress levels of an NMDS plot. Though similarities were recorded between impacted and reference sites, the results strongly showed that known impacted sites recorded the poorest water physico-chemistry, including the Yellowwoods River. However, the Laing Dam provided a buffer effect on contributions of the Yellowwoods River into the Buffalo River. Multivariate analysis showed that microbial cell counts were not influenced by water physico-chemical changes, whilst microbial activity from the water and biofilm habitats showed significant correlation levels to water physico-chemical changes. This study demonstrated that further investigations towards exploitation of microbial activity responses to water physico-chemical quality changes should be channelled towards the development of microbiological assessment index for inclusion in the RHP.
An investigation of the ecology of the Map Turtle, Graptemys geographica (Le Sueur), in the northern part of its range
- D M Gordon
- R D Maccolluch
Gordon, D.M., and R.D. MacColluch. 1980. An investigation of the ecology of the Map
Turtle, Graptemys geographica (Le Sueur), in the northern part of its range. Canadian
Journal of Zoology 58:2210-2219.
Stomach flushing: A technique for chelonian dietary studies
- J M Legler
Legler, J.M. 1977. Stomach flushing: A technique for chelonian dietary studies. Herpetologica 33:281-284.
Amphibians and Reptiles of Indiana (revised), 2 nd Edition
- S A Minton
Minton, S.A. 2001. Amphibians and Reptiles of Indiana (revised), 2 nd Edition. Indiana
Academy of Science, Indianapolis, IN, USA. 422 pp.
Life History and Ecology of the Slider Turtle
- R R Parmenter
- H W Avery
Parmenter, R.R., and H.W. Avery. 1980. The feeding ecology of the Slider Turtle. Pp. 257-266, In J.W. Gibbons (Ed.). Life History and Ecology of the Slider Turtle. Smithsonian
Institution Press, Washington, DC, USA. 368 pp.
Quickfacts United States
- Us Census
US Census. 2018. Quickfacts United States. Available online at https://www.census.gov/
quickfacts/fact/table/US/PST045217. 1 March 2018.