scholarly journals Intrinsic Prey Preference and Selection of the Giant Gartersnake: A Threatened Predator in a Nonnative Prey-Dominated Community

2020 ◽  
Vol 11 (1) ◽  
pp. 164-173
Author(s):  
Julia S.M. Ersan ◽  
Brian J. Halstead ◽  
Erica L. Wildy ◽  
Michael L. Casazza ◽  
Glenn D. Wylie
Keyword(s):  
Exotic Species ◽  
Native Species ◽  
Prey Selection ◽  
Central Valley ◽  
Prey Preference ◽  
Live Prey ◽  
Species Of Conservation Concern ◽  
Conservation Concern ◽  
Behavioral Trials ◽  
Selection Of

Abstract The introduction of exotic species into an environment can introduce great change in the trophic dynamics of native species. This is of even greater concern if the native species is of conservation concern. The giant gartersnake, Thamnophis gigas, an endemic predator of the Central Valley of California and a species of conservation concern at the state and federal levels, has declined as a result of conversion of its once vast wetland habitat to agriculture. Another anthropogenic factor contributing to this snake's changing ecology is the introduction of nonnative prey into the species' habitats. These introductions have resulted in a prey community that is almost completely composed of exotic species and have potential for considerable effects. In order to assess prey preference and selection we performed three sets of behavioral trials on naïve neonates. We examined 1) neonate prey preference in response to olfactory cues of prepared prey extracts, 2) neonate consumption of different live prey items presented simultaneously; and 3) terrestrial feeding behavior and/or latency to successful attack. Results from the olfactory study suggest that native Sierran treefrogs, Pseudacris sierra, are preferred by neonates. Results from consumption trials suggest that neonates are more likely to select frog species than fish species. This is the first study that we are aware of that examines prey selection of this threatened species and serves to inform its conservation and management.

The Ecology of the Dingo in Northeastern New-South-Wales .4. Prey Selection by Dingoes, and Its Effect on the Major Prey Species, the Swamp Wallaby, Wallabia-Bicolor (Desmarest)

1986 ◽  
Vol 13 (2) ◽  
pp. 141 ◽  
Author(s):  
JD Robertshaw ◽  
RH Harden
Keyword(s):  
Native Species ◽  
Prey Species ◽  
Prey Selection ◽  
New South ◽  
Optimal Foraging Theory ◽  
Major Effect ◽  
Breeding Cycle ◽  
South Wales ◽  
Swamp Wallaby ◽  
Selection Of

Prey selection and its effect on the major prey species was examined between 1979 and 1980 by comparing the diet of dingoes and the biology of the swamp wallaby at two sites where the relative numbers of dingoes and wallabies differed. Selection of prey by dingoes was not opportunistic but demonstrated a preference for larger native species, and was similar to that found in the same area between 1972 and 1974. In particular, dingoes had a strong preference for swamp wallaby, the occurrence of which in the diet was disproportionate to its observed numbers; and switching was not observed even when numbers of swamp wallaby were reduced and alternative macropod prey present. Contrary to Optimal Foraging Theory predictions that the predator should become more catholic in prey selection, this species was more frequent in the diet when its availability was lower. At one site the major effect of this predation was the disruption of the breeding cycle, as a result of the loss of large pouch young because of the harassment of their mothers.

Mutual dilution of infection by an introduced parasite in native and invasive stream fishes across Hawaii

Parasitology ◽  
2016 ◽  
Vol 143 (12) ◽  
pp. 1605-1614 ◽  
Author(s):  
RODERICK B. GAGNE ◽  
DAVID C. HEINS ◽  
PETER B. MCINTYRE ◽  
JAMES F. GILLIAM ◽  
MICHAEL J. BLUM
Keyword(s):  
Water Quality ◽  
Native Species ◽  
Host Density ◽  
Dilution Effect ◽  
Urban Land Use ◽  
Parasite Abundance ◽  
Species Of Conservation Concern ◽  
Awaous Stamineus ◽  
Conservation Concern ◽  
Camallanus Cotti

SUMMARYThe presence of introduced hosts can increase or decrease infections of co-introduced parasites in native species of conservation concern. In this study, we compared parasite abundance, intensity, and prevalence between nativeAwaous stamineusand introduced poeciliid fishes by a co-introduced nematode parasite (Camallanus cotti) in 42 watersheds across the Hawaiian Islands. We found that parasite abundance, intensity and prevalence were greater in native than introduced hosts. Parasite abundance, intensity and prevalence withinA. stamineusvaried between years, which largely reflected a transient spike in infection in three remote watersheds on Molokai. At each site we measured host factors (length, density of native host, density of introduced host) and environmental factors (per cent agricultural and urban land use, water chemistry, watershed area and precipitation) hypothesized to influenceC. cottiabundance, intensity and prevalence. Factors associated with parasitism differed between native and introduced hosts. Notably, parasitism of native hosts was higher in streams with lower water quality, whereas parasitism of introduced hosts was lower in streams with lower water quality. We also found that parasite burdens were lower in both native and introduced hosts when coincident. Evidence of a mutual dilution effect indicates that introduced hosts can ameliorate parasitism of native fishes by co-introduced parasites, which raises questions about the value of remediation actions, such as the removal of introduced hosts, in stemming the rise of infectious disease in species of conservation concern.

Reducing the primary exposure risk of Henderson crakes (Zapornia atra) during aerial broadcast eradication by selecting appropriate bait colour

2016 ◽  
Vol 43 (4) ◽  
pp. 298 ◽  
Author(s):  
Steffen Oppel ◽  
Jennifer L. Lavers ◽  
Alexander L. Bond ◽  
Gavin Harrison
Keyword(s):  
Mixed Models ◽  
Native Species ◽  
Exposure Risk ◽  
Island Endemic ◽  
Invasive Predators ◽  
Species Of Conservation Concern ◽  
In Captivity ◽  
Specific Variation ◽  
Conservation Concern ◽  
Native Invasive

Context Operations to eradicate non-native invasive predators from islands frequently put native species at risk of consuming harmful substances, such as poison bait. The incorporation of certain colours in poison-bait pellets may reduce the risk of bait consumption and, therefore, non-target mortality. Previous work indicated that birds generally avoid blue or green colours; however, there is substantial inter-specific variation in this preference, and more experimental work on species of conservation concern is needed. Aims We tested whether a globally threatened island endemic, the Henderson crake (Zapornia atra), which suffered substantial mortality during a rat-eradication attempt on Henderson Island in 2011, would consume fewer blue than green pellets, which were used during the previous eradication attempt. Methods We held 22 Henderson crakes in captivity and provided them with either blue or green non-toxic pellets for 5 days in June and July 2015. We measured consumption and used linear mixed models to evaluate whether bait colour influenced consumption. Key results Henderson crakes did not consume any dry pellets, and all trials were conducted with wet bait pellets. We found slightly lower consumption of blue pellets than green pellets, and substantial variation among individuals. Females (n = 17) consumed 24% less blue than green bait, whereas males (n = 5) consumed 77% less blue than green bait. Conclusion Henderson crakes are unlikely to consume dry pellets, and will likely consume fewer blue than green bait pellets. Implications We recommend that any future rat eradication on Henderson Island considers using blue rather than green baits and targets dry weather to reduce the risk of Henderson crakes consuming toxic rodenticide bait pellets.

scholarly journals Experimental removal of introduced slider turtles offers new insight into competition with a native, threatened turtle

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e7444 ◽  
Author(s):  
Max R. Lambert ◽  
Jennifer M. McKenzie ◽  
Robyn M. Screen ◽  
Adam G. Clause ◽  
Benjamin B. Johnson ◽  
...  
Keyword(s):  
Native Species ◽  
Field Experiments ◽  
Slider Turtle ◽  
Species Of Conservation Concern ◽  
Ecological Resources ◽  
Mesocosm Experiments ◽  
In The Wild ◽  
Western Pond Turtle ◽  
Negative Impacts ◽  
Conservation Concern

The red-eared slider turtle (Trachemys scripta elegans; RES) is often considered one of the world’s most invasive species. Results from laboratory and mesocosm experiments suggest that introduced RES outcompete native turtles for key ecological resources, but such experiments can overestimate the strength of competition. We report on the first field experiment with a wild turtle community, involving introduced RES and a declining native species of conservation concern, the western pond turtle (Emys marmorata; WPT). Using a before/after experimental design, we show that after removing most of an introduced RES population, the remaining RES dramatically shifted their spatial basking distribution in a manner consistent with strong intraspecific competition. WPT also altered their spatial basking distribution after the RES removal, but in ways inconsistent with strong interspecific competition. However, we documented reduced levels of WPT basking post-removal, which may reflect a behavioral shift attributable to the lower density of the turtle community. WPT body condition also increased after we removed RES, consistent with either indirect or direct competition between WPT and RES and providing the first evidence that RES can compete with a native turtle in the wild. We conclude that the negative impacts on WPT basking by RES in natural contexts are more limited than suggested by experiments with captive turtles, although wild WPT do appear to compete for food with introduced RES. Our results highlight the importance of manipulative field experiments when studying biological invasions, and the potential value of RES removal as a management strategy for WPT.

scholarly journals Diet of Lesser Scaup Wintering on Lake Pontchartrain, Louisiana

2019 ◽  
Vol 10 (2) ◽  
pp. 567-574
Author(s):  
Clay M. Stroud ◽  
Claire E. Caputo ◽  
Michael A. Poirrier ◽  
Kevin M. Ringelman
Keyword(s):  
Prey Selection ◽  
Seasonal Effects ◽  
Lake Pontchartrain ◽  
Management Actions ◽  
Lesser Scaup ◽  
Breeding Populations ◽  
Species Of Conservation Concern ◽  
Conservation Concern ◽  
Direct Management ◽  
Nutrient Reserves

Abstract The lesser scaup Aythya affinis has been a species of conservation concern since continental breeding populations began declining in the 1980s. The causes of this decline are likely multifaceted, but cross-seasonal effects are believed to play a prominent role: females unable to acquire sufficient nutrient reserves during winter and spring migration have poor survival and breeding success. Understanding scaup diet composition and prey selection can help managers not only diagnose mechanisms underlying wintering scaup distributions, but may also help direct management actions to increase forage availability and quality. We evaluated the diet of 60 scaup collected from a major wintering site in Louisiana, Lake Pontchartrain. Scaup consumed almost entirely mollusks, especially targeting medium-sized (6–16 mm) common rangia clams Rangia cuneata, which were strongly selected relative to their availability. Eighty-two percent of scaup consumed dark false mussels Mytilopsis leucophaeata and 57% consumed dwarf surf clams Mulinia lateralis; both foods were selected by scaup, but were uncommon in benthic samples. On the other hand, small snails Texadina sphinctostoma, Probythinella protera were common in dredge samples but were either avoided or consumed in proportion to their availability. We conclude that medium-sized common rangia clams and dark false mussels are the most consumed foods for scaup wintering on Lake Pontchartrain, and hypothesize that annual variation in prey populations may be an important proximate driver of scaup abundance.

scholarly journals New database of all marine species biological and traits

2015 ◽  
Author(s):  
Mark Costello ◽  
Simon Claus ◽  
Stefanie Dekeyzer ◽  
Leen Vandepitte ◽  
Dan Lear ◽  
...  
Keyword(s):  
Economic Status ◽  
Marine Species ◽  
Ecological Indicator ◽  
Species Status ◽  
Ecological Traits ◽  
Additional Information ◽  
Species Of Conservation Concern ◽  
Conservation Concern ◽  
New Research ◽  
Selection Of

The World Register of Marine Species (WoRMS) is being expanded to include species’ biological and ecological traits, and their socio-economic ‘status’. In contrast to traits, a species status may vary in place and time. However, a species status is of great importance to society and thus species of conservation concern, introduced, fishery or aquaculture resource, harmful, or used as an ecological indicator, are so noted in the database. WoRMS is a complete inventory of named marine species, managed by over 200 experts, and contains additional information and links on many species. We prioritised inclusion of traits where they could be applied to most taxa, were easily available, and their inclusion would result in new research and/or management applications. Numerical traits were favoured over categorical. The top ten prioritized were taxonomic classification, environment, geography, depth, substratum, mobility, skeleton, diet, body size and reproduction. Habitat can be derived from a selection of these traits. New use-cases may further subdivide and expand upon these traits. Each new attribute (trait or status) multiplies the number of analyses possible from the database. Contributions and enquiries are welcomed.

Diet composition and prey selection of vendace Coregonus albula in the mesotrophic, temperate Lake Ostrowite (Northern Poland)

2008 ◽  
Vol 37 (1) ◽  
Author(s):  
Tomasz Kakareko ◽  
Paweł Napiórkowski ◽  
Jacek Kozłowski
Keyword(s):  
Diet Composition ◽  
Prey Selection ◽  
Temperate Lake ◽  
Coregonus Albula ◽  
Northern Poland ◽  
Mesotrophic Lake ◽  
Selection Of

Diet composition and prey selection of vendaceLake Ostrowite is a mesotrophic lake in Northern Poland 280.7 ha in area and 43 m deep at its deepest point. To study vendace (

Climatic Variables Differentially Influence Neotropical Plant Species of Conservation Concern

2021 ◽  
pp. 1-16
Author(s):  
Pablo Antúnez ◽  
Christian Wehenkel ◽  
Collins Byobona Kukunda ◽  
José Ciro Hernández-Díaz
Keyword(s):  
Plant Species ◽  
Climatic Variables ◽  
Species Of Conservation Concern ◽  
Conservation Concern

Using impact assessment study designs for addressing impacts to species of conservation concern

2012 ◽  
Vol 36 (3) ◽  
pp. 450-456 ◽  
Author(s):  
Mike E. Marshall ◽  
Ashley M. Long ◽  
Shannon L. Farrell ◽  
Heather A. Mathewson ◽  
Michael L. Morrison ◽  
...  
Keyword(s):  
Impact Assessment ◽  
Impact Assessment Study ◽  
Assessment Study ◽  
Species Of Conservation Concern ◽  
Conservation Concern ◽  
Study Designs

scholarly journals White-nose syndrome-related changes to Mid-Atlantic bat communities across an urban-to-rural gradient

BMC Zoology ◽  
2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Sabrina Deeley ◽  
Joshua B. Johnson ◽  
W. Mark Ford ◽  
J. Edward Gates
Keyword(s):  
The United States ◽  
Myotis Lucifugus ◽  
National Capital Region ◽  
Conservation Areas ◽  
White Nose Syndrome ◽  
Species Of Conservation Concern ◽  
National Capital ◽  
Park Service ◽  
Bat Conservation ◽  
Conservation Concern

Abstract Background White-nose Syndrome (WNS) has reduced the abundance of many bat species within the United States’ Mid-Atlantic region. To determine changes within the National Park Service National Capital Region (NCR) bat communities, we surveyed the area with mist netting and active acoustic sampling (2016–2018) and compared findings to pre-WNS (2003–2004) data. Results The results indicated the continued presence of the threatened Myotis septentrionalis (Northern Long-eared bat) and species of conservation concern, including Perimyotis subflavus (Tri-colored bat), Myotis leibii (Eastern Small-footed bat) and Myotis lucifugus (Little Brown bat). However, we documented a significant reduction in the abundance and distribution of M. lucifugus and P. subflavus, a decrease in the distribution of M. septentrionalis, and an increase in the abundance of Eptesicus fuscus (Big Brown bat). Conclusions Documented post-WNS M. septentrionalis recruitment suggests that portions of the NCR may be important bat conservation areas. Decreases in distribution and abundance of P. subflavus and M. lucifugus indicate probable extirpation from many previously occupied portions of the region.

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