Preliminary evidence suggests freshwater turtles respond positively to an environmental water delivery during drought

2016 ◽  
Vol 64 (5) ◽  
pp. 370 ◽  
Author(s):  
K. Howard ◽  
L. Beesley ◽  
K. Ward ◽  
D. Stokeld
Keyword(s):  
Body Condition ◽  
Environmental Flows ◽  
Environmental Water ◽  
Preliminary Evidence ◽  
Regulated River ◽  
Management Tool ◽  
Freshwater Turtles ◽  
Catch Per Unit Effort ◽  
Chelodina Longicollis ◽  
Average Body

Environmental flows (e-flows) are a common management tool to improve the health of flow-regulated river systems and their biota. The effect of e-flows on fish, waterbirds and vegetation has been assessed in Australia, but their influence on turtles remains largely unstudied. We opportunistically examined the effect of e-flows on the eastern long-necked turtle (Chelodina longicollis), a species that occupies ephemeral aquatic habitats, by measuring an index of abundance (catch per unit effort) and body condition before and after an environmental watering event that replenished a severely contracted creek in the mid-Murray region. We found that average body condition increased after watering. Abundance decreased markedly after watering, but the change was not statistically significant. While the causal inference of our study was limited by the opportunistic nature of our before-after experimental design, this study provides preliminary evidence that environmental flows may improve the health of turtles occupying ephemeral floodplain habitats. We encourage further research into the effect of e-flows on turtles to confirm the hypothesis that the increase in average body condition recorded in the current study was a function of e-flows.

Declines of freshwater turtles associated with climatic drying in Australia

2011 ◽  
Vol 38 (8) ◽  
pp. 664 ◽  
Author(s):  
Bruce C. Chessman
Keyword(s):  
River Flow ◽  
Freshwater Turtle ◽  
Severe Drought ◽  
Freshwater Turtles ◽  
Catch Per Unit Effort ◽  
Unit Effort ◽  
Murray River ◽  
Floodplain Inundation ◽  
Global Impacts ◽  
Chelodina Longicollis

Context While much attention has been paid to the effects of global temperature increases on the geographical ranges and phenologies of plants and animals, less is known about the impacts of climatically driven alteration of water regimes. Aims To assess how three species of freshwater turtle in Australia’s Murray–Darling Basin have responded to long-term decline in river flow and floodplain inundation due to climatic drying and water diversions. Methods Turtle populations were sampled in a section of the Murray River and its floodplain in 1976–82 following a wet period and in 2009–11 at the end of the most severe drought on record. Catch per unit effort, proportional abundance in different habitat types and population structure were assessed in both periods. Key results Catch per unit effort in baited hoop nets declined by 91% for the eastern snake-necked turtle (Chelodina longicollis) and 69% for the Murray turtle (Emydura macquarii), but did not change significantly for the broad-shelled turtle (Chelodina expansa). In addition, total catches from a range of sampling methods revealed a significantly reduced proportion of juvenile C. longicollis and E. macquarii in 2009–11, suggesting a fall in recruitment. Key conclusions The decline of C. longicollis was likely due mainly to drought-induced loss of critical floodplain habitat in the form of temporary water bodies, and that of E. macquarii to combined effects of drought and predation on recruitment. C. expansa seems to have fared better than the other two species because it is less vulnerable to nest predation than E. macquarii and better able than C. longicollis to find adequate nutrition in the permanent waters that remain during extended drought. Implications Declining water availability may be a widespread threat to freshwater turtles given predicted global impacts of climate change and water withdrawals on river flows. Understanding how each species uses particular habitats and how climatic and non-climatic threats interact would facilitate identification of vulnerable populations and planning of conservation actions.

Examining the impacts of red deer hind body condition score and pasture forage mass on calf weaning weight

2017 ◽  
Vol 57 (3) ◽  
pp. 466 ◽  
Author(s):  
D. R. Stevens ◽  
B. R. Thompson ◽  
G. W. Asher ◽  
I. C. Scott
Keyword(s):  
Body Condition ◽  
Cervus Elaphus ◽  
Red Deer ◽  
Body Condition Score ◽  
Restricted Feeding ◽  
Weaning Weight ◽  
Calf Growth ◽  
Total Milk ◽  
Condition Score ◽  
Average Body

The effect of pre-calving hind body condition and the interaction with pasture forage mass during lactation on calf growth and intake to weaning were investigated. Two-hundred and forty red deer hinds (Cervus elaphus scoticus × hippelaphus) of average body condition score (BCS) 3.5 were subjected to either ad libitum or restricted feeding for the 4 weeks before the expected start of calving (31 October) to create hinds of low (2.5) or high (3.5) BCS. The hinds were then grazed continuously on pasture of either low (<1200 kg DM/ha) or high (>2400 kg DM/ha) forage mass during lactation (29 October–25 March). In a 2 × 2 crossover design liveweight, liveweight gain and pasture intake were measured in both hinds and calves. Low hind body condition score (BCS 2.5) at the onset of lactation resulted in low calf weaning weight (46.9 kg) when forage mass was low, but not when forage mass was high (57.3 kg). High BCS (3.5) in hinds resulted in intermediate calf weaning weight when on low forage mass (51.2 kg) and high calf weaning weight when forage mass was high (56.6 kg). Both BCS and forage mass influenced calculated total milk production.

Effects of canine heartworm (Dirofilaria immitis) on body condition and activity of free-ranging coyotes (Canis latrans)

2000 ◽  
Vol 78 (6) ◽  
pp. 1042-1051 ◽  
Author(s):  
Benjamin N Sacks ◽  
Karen M Blejwas
Keyword(s):  
Body Mass ◽  
Body Condition ◽  
Dirofilaria Immitis ◽  
Canis Latrans ◽  
Infected Group ◽  
Control Group ◽  
Canine Heartworm ◽  
Average Body Mass ◽  
Free Ranging ◽  
Average Body

We used radiotelemetry to study relationships among canine heartworm (Dirofilaria immitis) infection, body condition, and activity of free-ranging coyotes (Canis latrans). Average body mass at death was lower for 17 coyotes in a high-intensity infected group (mean = 33.6 heartworms) than for 18 coyotes in a control group (mean = 3.6 heartworms; p < 0.01). Coyotes in the infected group lost body mass at an average rate of 20% per year relative to the control group (p < 0.01). Bone marrow fat was negatively correlated with heartworm burden (R2 = 0.27; p < 0.01). Average body mass of coyotes at initial capture (i.e., potentially before infection) did not differ between infected and control groups (p = 0.90; 1–β = 0.70). Activity was negatively correlated with heartworm burden during the last 2 months of life (R2 = 0.30; p < 0.01), but no correlation was found 2–4 months before death. Activity of the infected group (n = 13) declined over time (p = 0.01), whereas no difference in activity was observed in the control group (n = 13; p = 0.50). Our findings indicate that heartworm infection reduced body condition and activity of coyotes but that nutritional status did not significantly affect susceptibility to infection.

Food abundance and diet variation in freshwater turtles from the mid-Murray River, Australia

2018 ◽  
Vol 66 (1) ◽  
pp. 67 ◽  
Author(s):  
Kristen Petrov ◽  
Jessica Lewis ◽  
Natasha Malkiewicz ◽  
James U. Van Dyke ◽  
Ricky-John Spencer
Keyword(s):  
Green Algae ◽  
Prey Availability ◽  
Foraging Strategies ◽  
Freshwater Turtles ◽  
Food Items ◽  
Filamentous Green Algae ◽  
Invertebrate Diversity ◽  
Murray River ◽  
Specialist Species ◽  
Chelodina Longicollis

Consumers usually respond to variations in prey availability by altering their foraging strategies. Generalist consumers forage on a diversity of resources and have greater potential to ‘switch’ their diet in response to fluctuations in prey availability, in comparison to specialist consumers. We aimed to determine how the diets of two specialist species (the eastern long-necked turtle (Chelodina longicollis) and the broad-shelled turtle (Chelodina expansa) and the more generalist Murray River short-necked turtle (Emydura macquarii) respond to variation in habitat and prey availability. We trapped and stomach-flushed turtles, and compared their diets along with environmental variables (turbidity, macrophyte and filamentous green algae cover, and aquatic invertebrate diversity and abundance) at four wetlands in north-central Victoria. Diets of E. macquarii differed from those of both Chelodina species, which overlapped, across all four sites. However, samples sizes for the two Chelodina species were too small to compare among-wetland variation in diet. Dietary composition of E. macquarii was variable but did not differ statistically among sites. Emydura macquarii preferentially selected filamentous green algae at three of the four sites. Where filamentous green algae were rare, total food bolus volume was reduced and E. macquarii only partially replaced it with other food items, including other vegetation, wood, and animal prey. Many turtles at these sites also had empty stomachs. Thus, filamentous green algae may be a limiting food for E. macquarii. Although E. macquarii has previously been described as a generalist, it appears to have limited ability to replace filamentous green algae with other food items when filamentous green algae are rare.

scholarly journals From an irrigation system to an ecological asset: adding environmental flows establishes recovery of a threatened fish species

2019 ◽  
Vol 70 (9) ◽  
pp. 1295 ◽  
Author(s):  
Ivor Stuart ◽  
Clayton Sharpe ◽  
Kathryn Stanislawski ◽  
Anna Parker ◽  
Martin Mallen-Cooper
Keyword(s):  
Water Level ◽  
Fish Species ◽  
Life Histories ◽  
Environmental Flows ◽  
Irrigation System ◽  
Spatial Scales ◽  
Environmental Water ◽  
Environmental Flow ◽  
Murray Cod ◽  
Riverine Fish

Worldwide, riverine fish are the target of environmental water because populations have declined in lotic river habitats following river regulation. Murray cod is an endangered Australian riverine fish with remaining populations associated with lotic river reaches with instream habitat, including some creeks operated as part of irrigation systems. Our objectives were to develop a life history model, apply the building block method of environmental flows to enhance the abundance of juvenile Murray cod and promote population recovery. From 2008 to 2018 we evaluated changes to Murray cod juvenile abundance before and after implementation of a perennial environmental flow regime that began in 2013. During the first year of the environmental flow, larvae were collected as evidence of spawning. Murray cod abundance can be enhanced with environmental flows that target: (1) an annual spring spawning or recruitment flow with no rapid water level drops; (2) maximising hydrodynamic complexity (i.e. flowing habitats that are longitudinally continuous and hydrodynamically complex); and (3) an annual base winter connection flow. Recognition that incorporating hydraulics (water level and velocity) at fine and coarse time scales, over spatial scales that reflect life histories, provides broader opportunities to expand the scope of environmental flows to help restore imperilled fish species in regulated ecosystems.

Ecological and physiological impacts of salinisation on freshwater turtles of the lower Murray River

2012 ◽  
Vol 39 (8) ◽  
pp. 705 ◽  
Author(s):  
Deborah S. Bower ◽  
Clare E. Death ◽  
Arthur Georges
Keyword(s):  
Saline Lake ◽  
South Australia ◽  
Freshwater Turtle ◽  
Plasma Sodium ◽  
Freshwater Species ◽  
Freshwater Turtles ◽  
Brackish Lake ◽  
Ecological Processes ◽  
Murray River ◽  
Chelodina Longicollis

Context The increasing intensity and extent of anthropogenically mediated salinisation in freshwater systems has the potential to affect freshwater species through physiological and ecological processes. Determining responses to salinisation is critical to predicting impacts on fauna. Aims We aimed to quantify the response of wild-caught turtles from freshwater lakes that had become saline in the lower Murray River catchment. Methods Plasma electrolytes of all three species of freshwater turtle from South Australia were compared among two freshwater sites (Horseshoe Lagoon and Swan Reach), a brackish lake (Lake Bonney) and a saline lake (Lake Alexandrina). Key results Chelodina longicollis, C. expansa and Emydura macquarii from a brackish lake had higher concentrations of plasma sodium and chloride than those from freshwater habitats. However, osmolytes known to increase under severe osmotic stress (urea and uric acid) were not elevated in brackish sites. Turtles from the highly saline lake were colonised by an invasive marine worm which encased the carapace and inhibited limb movement. Conclusions Freshwater turtles in brackish backwaters had little response to salinity, whereas the C. longicollis in a saline lake had a significant physiological response caused by salt and further impacts from colonisation of marine worms. Implications Short periods of high salinity are unlikely to adversely affect freshwater turtles. However, secondary ecological processes, such as immobilisation from a marine worm may cause unexpected impacts on freshwater fauna.

scholarly journals A critical analysis of regulated river ecosystem responses to managed environmental flows from reservoirs

2014 ◽  
Vol 60 (2) ◽  
pp. 410-425 ◽  
Author(s):  
Ben R. Gillespie ◽  
Simon Desmet ◽  
Paul Kay ◽  
Martin R. Tillotson ◽  
Lee E. Brown
Keyword(s):  
Critical Analysis ◽  
Environmental Flows ◽  
Regulated River ◽  
River Ecosystem ◽  
Ecosystem Responses

Response of a floodplain fish community to river-floodplain connectivity: natural versus managed reconnection

2014 ◽  
Vol 71 (2) ◽  
pp. 236-245 ◽  
Author(s):  
R.J. Stoffels ◽  
K.R. Clarke ◽  
R.A. Rehwinkel ◽  
B.J. McCarthy
Keyword(s):  
Native Species ◽  
Fish Community ◽  
Large Scale ◽  
Environmental Flows ◽  
Regulated River ◽  
Pest Species ◽  
Fish Community Structure ◽  
River Floodplain ◽  
Natural Connection ◽  
Flood Pulses

To restore lateral connectivity in highly regulated river-floodplain systems, it has become necessary to implement localized, “managed” connection flows, made possible using floodplain irrigation infrastructure. These managed flows contrast with “natural”, large-scale, overbank flood pulses. We compared the effects of a managed and a natural connection event on (i) the composition of the large-bodied fish community and (ii) the structure of an endangered catfish population of a large floodplain lake. The change in community composition following the managed connection was not greater than that exhibited between seasons or years during disconnection. By contrast, the change in fish community structure following the natural connection was much larger than that attributed to background, within- and between-year variability during disconnection. Catfish population structure only changed significantly following the natural flood. While the natural flood increased various population rates of native fishes, it also increased those of non-native carp, a pest species. To have a positive influence on native biodiversity, environmental flows may need to be delivered to floodplains in a way that simulates the properties of natural flood pulses. A challenge, however, will be managing river-floodplain connectivity to benefit native more than non-native species.

scholarly journals The relationship between pink salmon biomass and the body condition of short-tailed shearwaters in the Bering Sea: can fish compete with seabirds?

2011 ◽  
Vol 278 (1718) ◽  
pp. 2584-2590 ◽  
Author(s):  
Kanako Toge ◽  
Rei Yamashita ◽  
Kentaro Kazama ◽  
Masaaki Fukuwaka ◽  
Orio Yamamura ◽  
...  
Keyword(s):  
Body Condition ◽  
Bering Sea ◽  
Pink Salmon ◽  
The Body ◽  
Oncorhynchus Gorbuscha ◽  
Catch Per Unit Effort ◽  
Study Region ◽  
Top Predators ◽  
The Relationship ◽  
The Bering Sea

Seabirds and large fishes are important top predators in marine ecosystems, but few studies have explored the potential for competition between these groups. This study investigates the relationship between an observed biennial change of pink salmon ( Oncorhynchus gorbuscha ) biomass in the central Bering Sea (23 times greater in odd-numbered than in even-numbered years) and the body condition and diet of the short-tailed shearwater ( Puffinus tenuirostris ) that spends the post-breeding season there. Samples were collected with research gill nets over seven summers. Both species feed on krill, small fishes and squid. Although the mean pink salmon catch per unit effort (in mass) over the study region was not related significantly with shearwater's stomach content mass or prey composition, the pink salmon biomass showed a negative and significant relationship with the shearwater's body mass and liver mass (proxies of energy reserve). We interpret these results as evidence that fishes can negatively affect mean prey intake of seabirds if they feed on a shared prey in the pelagic ecosystem.

A Ramsar wetland in crisis - the Coorong, Lower Lakes and Murray Mouth, Australia

2011 ◽  
Vol 62 (3) ◽  
pp. 255 ◽  
Author(s):  
Richard T. Kingsford ◽  
Keith F. Walker ◽  
Rebecca E. Lester ◽  
William J. Young ◽  
Peter G. Fairweather ◽  
...  
Keyword(s):  
Environmental Flows ◽  
Large River ◽  
Freshwater Ecosystems ◽  
Water Levels ◽  
Environmental Benefits ◽  
Low Flow ◽  
Freshwater Turtles ◽  
Murray Darling Basin ◽  
High Conservation ◽  
Sulfate Soils

The state of global freshwater ecosystems is increasingly parlous with water resource development degrading high-conservation wetlands. Rehabilitation is challenging because necessary increases in environmental flows have concomitant social impacts, complicated because many rivers flow between jurisdictions or countries. Australia’s Murray–Darling Basin is a large river basin with such problems encapsulated in the crisis of its Ramsar-listed terminal wetland, the Coorong, Lower Lakes and Murray Mouth. Prolonged drought and upstream diversion of water dropped water levels in the Lakes below sea level (2009–2010), exposing hazardous acid sulfate soils. Salinities increased dramatically (e.g. South Lagoon of Coorong >200 g L–1, cf. modelled natural 80 g L–1), reducing populations of waterbirds, fish, macroinvertebrates and littoral plants. Calcareous masses of estuarine tubeworms (Ficopomatus enigmaticus) killed freshwater turtles (Chelidae) and other fauna. Management primarily focussed on treating symptoms (e.g. acidification), rather than reduced flows, at considerable expense (>AU$2 billion). We modelled a scenario that increased annual flows during low-flow periods from current levels up to one-third of what the natural flow would have been, potentially delivering substantial environmental benefits and avoiding future crises. Realisation of this outcome depends on increasing environmental flows and implementing sophisticated river management during dry periods, both highly contentious options.

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