scholarly journals The impact of mammalian insectivores Rattus rattus (Rat), Mus musculus (Mouse) & Erinaceus europeus (Hedgehog) on the size and abundance of mainland Coleoptera and Orthoptera

2021 ◽  
Author(s):  
◽  
Thomas Hewitt
Keyword(s):  
Mus Musculus ◽  
Rattus Rattus ◽  
Temporal Analysis ◽  
Invertebrate Communities ◽  
Introduced Predators ◽  
Mammalian Predators ◽  
Study Sites ◽  
Tree Weta ◽  
Occupancy Rates ◽  
The Impact

<p>The impact of introduced mammalian predators on indigenous vertebrates is relatively well documented, however the general responses of indigenous invertebrate communities is less well known. Many indigenous invertebrates, particularly the large flightless species such as those in the genus Deinacrida (Orthoptera) and Anagotus (Curculionidae) have been extirpated from much of their range due largely to the impacts of introduced predators. Despite these well-known examples very little is known about the general impact of introduced predators on invertebrate communities. Beginning in 2012 pitfall traps and artificial wētā motels were established across seven study sites in the Aorangi and Remutaka ranges east of Wellington alternately baited with squid and monitored two to three times annually. Mammal tracking took place in the form of tracking tunnels giving three mammal indexes for rats (Rattus rattus), mice (Mus musculus) and hedgehogs (Erinaceus europeus). Cavity dwelling wētā in wētā motels were measured and counted in situ whilst pitfall trapped Coleoptera and Orthoptera were transported to the lab for measuring and identification. Linear mixed effects model, type 3 ANOVAS and generalised linear mixed models were used to examine whether mammal index had any impact on the size and the catch or occupancy of invertebrates. Increased rat and mouse tracking was associated with reduced coleoptera catch whilst increased hedgehog tracking was correlated with increases in Coleoptera catch. Pitfall trapped wētā (Hemiandrus spp) showed strong negative responses to increased rat tracking, neutral responses to mice and positive responses to hedgehogs. Tree wētā (Hemideina crassidens) occupancy rates declined in response to increased mouse abundance whilst the mean size of tree wētā residing in wētā motels showed an increase in response to rats and mice. These results show the complexity of understanding mammal invertebrate interactions which cannot be expected to be the same in all environments or across all taxa. Environmental factors typically impact far more strongly on invertebrate populations than they do on vertebrates and can obscure the impacts of top down predation in such studies. The results reported in this study only became apparent after 5+ years of sampling, demonstrating the importance of long-term temporal analysis of invertebrate communities in response to mammals before trends start to emerge. More research is required into the basic ecology and population dynamics of invertebrate communities before more general trends can be discerned.</p>

The impact of mammalian insectivores Rattus rattus (Rat), Mus musculus (Mouse) & Erinaceus europeus (Hedgehog) on the size and abundance of mainland Coleoptera and Orthoptera

2021 ◽  
Author(s):  
◽  
Thomas Hewitt
Keyword(s):  
Mus Musculus ◽  
Rattus Rattus ◽  
Temporal Analysis ◽  
Invertebrate Communities ◽  
Introduced Predators ◽  
Mammalian Predators ◽  
Study Sites ◽  
Tree Weta ◽  
Occupancy Rates ◽  
The Impact

<p>The impact of introduced mammalian predators on indigenous vertebrates is relatively well documented, however the general responses of indigenous invertebrate communities is less well known. Many indigenous invertebrates, particularly the large flightless species such as those in the genus Deinacrida (Orthoptera) and Anagotus (Curculionidae) have been extirpated from much of their range due largely to the impacts of introduced predators. Despite these well-known examples very little is known about the general impact of introduced predators on invertebrate communities. Beginning in 2012 pitfall traps and artificial wētā motels were established across seven study sites in the Aorangi and Remutaka ranges east of Wellington alternately baited with squid and monitored two to three times annually. Mammal tracking took place in the form of tracking tunnels giving three mammal indexes for rats (Rattus rattus), mice (Mus musculus) and hedgehogs (Erinaceus europeus). Cavity dwelling wētā in wētā motels were measured and counted in situ whilst pitfall trapped Coleoptera and Orthoptera were transported to the lab for measuring and identification. Linear mixed effects model, type 3 ANOVAS and generalised linear mixed models were used to examine whether mammal index had any impact on the size and the catch or occupancy of invertebrates. Increased rat and mouse tracking was associated with reduced coleoptera catch whilst increased hedgehog tracking was correlated with increases in Coleoptera catch. Pitfall trapped wētā (Hemiandrus spp) showed strong negative responses to increased rat tracking, neutral responses to mice and positive responses to hedgehogs. Tree wētā (Hemideina crassidens) occupancy rates declined in response to increased mouse abundance whilst the mean size of tree wētā residing in wētā motels showed an increase in response to rats and mice. These results show the complexity of understanding mammal invertebrate interactions which cannot be expected to be the same in all environments or across all taxa. Environmental factors typically impact far more strongly on invertebrate populations than they do on vertebrates and can obscure the impacts of top down predation in such studies. The results reported in this study only became apparent after 5+ years of sampling, demonstrating the importance of long-term temporal analysis of invertebrate communities in response to mammals before trends start to emerge. More research is required into the basic ecology and population dynamics of invertebrate communities before more general trends can be discerned.</p>

scholarly journals The impacts of an introduced mammalian predator (Mus musculus) on tree weta (Hemideina trewicki) and skinks (Oligosoma polychroma, Oligosoma infrapunctatum and Oligosoma lineoocellatum) in Cape Sanctuary, Hawkes Bay

2021 ◽  
Author(s):  
◽  
Emma Dent
Keyword(s):  
Native Species ◽  
Conservation Management ◽  
Limiting Factor ◽  
Pitfall Traps ◽  
Mark Recapture ◽  
Introduced Predators ◽  
Native Populations ◽  
Mammalian Predator ◽  
Tree Weta ◽  
The Impact

<p>The introduction of exotic species, particularly predators, into new ecosystems is one of the biggest causes of loss of biodiversity across the globe. Understanding the impacts that introduced species have on native species is crucial in conservation management, particularly for those species that are conservation-reliant. I examined the impact that an introduced mammalian predator (Mus muscularus) had on native prey populations of common (Oligosoma polychroma), speckled (Oligosoma infrapunctatum) and spotted (Oligosoma lineoocellatum) skinks and Hawkes Bay tree weta (Hemideina trewicki). I conducted a mark-recapture study using pitfall traps to examine the impact of mice on skink populations. I conducted a mark-recapture study through manual counts to examine the impact of mice on tree weta. I also examined occupancy of weta refuges while in the presence of mice. There were no captures of spotted skinks, and very low captures of common skinks. There was no significant change in capture numbers for speckled skink, however observed numbers did decline from November 2013 to November 2014. There was a significant decline in capture rates for tree weta over the course of my study. It was difficult to establish mice as the sole cause of any observed changes, however it is likely that they are a limiting factor for skink and weta populations, and have the potential to be a major factor in the observed decline in the tree weta population. My results highlight the importance of monitoring native populations, particularly those that are small and are in the presence of introduced predators. By monitoring native populations conservation management can make better informed decisions to work towards populations not being ‘conservation-reliant’.</p>

scholarly journals The impacts of an introduced mammalian predator (Mus musculus) on tree weta (Hemideina trewicki) and skinks (Oligosoma polychroma, Oligosoma infrapunctatum and Oligosoma lineoocellatum) in Cape Sanctuary, Hawkes Bay

2021 ◽  
Author(s):  
◽  
Emma Dent
Keyword(s):  
Native Species ◽  
Conservation Management ◽  
Limiting Factor ◽  
Pitfall Traps ◽  
Mark Recapture ◽  
Introduced Predators ◽  
Native Populations ◽  
Mammalian Predator ◽  
Tree Weta ◽  
The Impact

<p>The introduction of exotic species, particularly predators, into new ecosystems is one of the biggest causes of loss of biodiversity across the globe. Understanding the impacts that introduced species have on native species is crucial in conservation management, particularly for those species that are conservation-reliant. I examined the impact that an introduced mammalian predator (Mus muscularus) had on native prey populations of common (Oligosoma polychroma), speckled (Oligosoma infrapunctatum) and spotted (Oligosoma lineoocellatum) skinks and Hawkes Bay tree weta (Hemideina trewicki). I conducted a mark-recapture study using pitfall traps to examine the impact of mice on skink populations. I conducted a mark-recapture study through manual counts to examine the impact of mice on tree weta. I also examined occupancy of weta refuges while in the presence of mice. There were no captures of spotted skinks, and very low captures of common skinks. There was no significant change in capture numbers for speckled skink, however observed numbers did decline from November 2013 to November 2014. There was a significant decline in capture rates for tree weta over the course of my study. It was difficult to establish mice as the sole cause of any observed changes, however it is likely that they are a limiting factor for skink and weta populations, and have the potential to be a major factor in the observed decline in the tree weta population. My results highlight the importance of monitoring native populations, particularly those that are small and are in the presence of introduced predators. By monitoring native populations conservation management can make better informed decisions to work towards populations not being ‘conservation-reliant’.</p>

scholarly journals The impact of introduced predators on an island endemic, the St Helena Plover, Charadrius sanctaehelenae

2013 ◽  
Vol 23 (2) ◽  
pp. 125-135 ◽  
Author(s):  
FIONA BURNS ◽  
NEIL MCCULLOCH ◽  
TAMÁS SZÉKELY ◽  
MARK BOLTON
Keyword(s):  
Rattus Rattus ◽  
Population Level ◽  
Domestic Cat ◽  
Predator Species ◽  
Island Endemic ◽  
Common Myna ◽  
Introduced Predators ◽  
St Helena ◽  
Future Work ◽  
The Impact

SummaryWe investigated the impact of introduced predators on the productivity of the St Helena Plover Charadrius sanctaehelenae, a shorebird endemic to the South Atlantic island of St Helena. The nest predator species identified have all been introduced to St Helena in the last 510 years, and all are species that are known to be invasive on other islands. The species responsible for taking the largest proportion of eggs was the domestic cat Felis catus, with rats (Rattus rattus or R. norvegicus) and Common Myna Acridotheres tristis taking smaller proportions. Nest survival varied spatially and was correlated with an index of cat density. No relationship was observed between the number of nesting attempts per pair in a year and predator density. The resulting estimates of productivity were insufficient in some areas to allow stable populations to persist locally. Future work should focus on assessing the population level impacts of current and reduced predator densities to St Helena Plovers, and understanding the influence of resource availability and habitat structure on the densities and impacts of predators.

Drought increases the impact of introduced European foxes on breeding Australian pelicans

2016 ◽  
Vol 43 (6) ◽  
pp. 507 ◽  
Author(s):  
Gregory R. Johnston
Keyword(s):  
Path Analysis ◽  
South Australia ◽  
Breeding Population ◽  
Population Declines ◽  
Egg Mortality ◽  
Eradication Program ◽  
Introduced Predators ◽  
Mammalian Predators ◽  
Colonial Waterbirds ◽  
The Impact

Context Introduced mammalian predators have been responsible for population declines in native prey species around the world. Many conservation programs rely on control or eradication of introduced mammalian predators, but the impact of environmental variation on the efficacy of this approach is rarely documented. Aims The present paper describes (1) the impact of introduced European foxes (Vulpes vulpes) on breeding Australian pelicans (Pelecanus conspicillatus) in South Australia and (2) the responses of both species to a fox-eradication program using a before-after-impact framework. Methods The impact of foxes on breeding Australian pelicans was studied on a near-shore island. An index of fox abundance and direct measurements of breeding pelicans and mortality of pelican eggs and young were compared before foxes were established on the island, while foxes were resident and during a fox-eradication program. A path analysis was used to explore the causal relationships between fox abundance and other potential covariates (e.g. rainfall) on breeding pelicans. Key results Before foxes were established on the island, the number of breeding pelicans grew and egg mortality was low. While foxes were resident, the number of breeding pelicans fell and egg mortality rose. This was followed by an increase in the number of breeding pelicans and a decrease in egg mortality during a fox-eradication program. While foxes had a clear impact on egg mortality, a period of low rainfall also occurred while foxes were resident. The path analysis showed an interaction among rainfall, size of the pelican breeding population and the impact of foxes. In drought years, fewer pelicans bred and foxes were a major cause of nest abandonment when they entered pelican breeding colonies to prey on eggs. Conclusions These results confirmed that foxes can be an important predator of ground-nesting, colonial waterbirds, and showed that the impact of foxes may be higher in drought years when prey populations are low. Implications The present study suggests that an increase in the incidence of droughts as a result of climate change may increase the impact of introduced predators on drought-sensitive waterbirds and raises the possibility of focussing predator-control efforts during droughts, as periods of particular risk to colony-breeding waterbirds.

Detecting predation of a burrow-nesting seabird by two introduced predators, using stable isotopes, dietary analysis and experimental removals

2007 ◽  
Vol 34 (6) ◽  
pp. 443 ◽  
Author(s):  
Grant A. Harper
Keyword(s):  
Rattus Rattus ◽  
Isotopic Analysis ◽  
Diet Analysis ◽  
Passerine Birds ◽  
Dietary Analysis ◽  
Stable Isotopic Analysis ◽  
Introduced Predators ◽  
Ship Rat ◽  
Stable Isotopic ◽  
Burrowing Seabirds

Burrowing seabirds are vulnerable to extirpation by introduced predators such as rats, but much evidence of predation is circumstantial. On Taukihepa, an island off southern New Zealand, two possible predators exist with sooty shearwaters (Puffinus griseus): the weka (Gallirallus australis), a large rail, and the ship rat (Rattus rattus), both introduced to the island. It was expected that chick predation would be principally by weka, the much larger of the two predators. To measure losses of sooty shearwater chicks to weka or rats, nests were monitored with burrow-scopes at six sites in the summers of 2003–04 and 2004–05. In three of the sites rats were removed on 4-ha grids by trapping. In the other three sites rats were not trapped. In addition, weka were removed from all six sites in 2005. Concurrent diet analysis of weka and rat stomachs was undertaken as well as stable isotopic analysis (δ13C, δ15N) of samples from rats and weka. These were compared with possible prey items including sooty shearwaters. Additional stable isotope samples were taken from Pacific rats (Rattus exulans), a small rat species present with weka and sooty shearwaters on nearby Moginui Island. Weka diet comprised ~40% of bird remains by volume and calculations using Isosource, an isotopic source portioning model, estimated sooty shearwaters contributed 59% (range: 15–71%) of weka diet during the sooty shearwater chick-raising period. Ship rats, in contrast, had very depleted δ13C isotope signatures compared with sooty shearwaters and bird remains contributed <9% of diet by volume, with Isosource calculations suggesting that ship rats consumed more passerine birds (mean: 30%; range 5–51%) than sooty shearwaters (mean 24%; range: 0–44%). In both summers, more chicks were lost on sites from which rats had been removed than on control sites. When weka were removed in 2005, fewer chicks were lost than in 2004 and significantly fewer weka-killed chicks were found on weka-removal sites than on non-removal sites. Weka were the principal predator of sooty shearwater chicks, depredating an estimated 9.9% of nests. Combining several techniques quantified the loss and identified the principal predator of a seabird in decline.

Introduced predators and cavity-nesting seabirds: unexpected low level of interaction at breeding sites

2008 ◽  
Vol 86 (9) ◽  
pp. 1068-1073 ◽  
Author(s):  
L. Ruffino ◽  
K. Bourgeois ◽  
E. Vidal ◽  
J. Icard ◽  
F. Torre ◽  
...  
Keyword(s):  
Rattus Rattus ◽  
Breeding Cycle ◽  
Mediterranean Islands ◽  
Breeding Sites ◽  
Low Level ◽  
Black Rat ◽  
Cavity Nesting ◽  
Introduced Predators ◽  
Puffinus Yelkouan ◽  
First Time

The mechanisms by which introduced predators and long-lived seabirds interact and even coexist are still poorly known. Here, the interactions between the widely introduced black rat ( Rattus rattus (L., 1758)) and an endemic Mediterranean cavity-nesting seabird, the yelkouan shearwater ( Puffinus yelkouan (Acerbi, 1827)), were for the first time investigated for a set of 60 suitable breeding cavities throughout the entire breeding cycle of this seabird. Our results pointed out that rat visits to cavities were significantly higher when shearwaters had left the colony for their interbreeding exodus. Among the set of suitable breeding cavities, yelkouan shearwaters preferentially selected the deepest and the most winding cavities for breeding. Very few rat visits were recorded at the shearwater-occupied cavities and no predation event was recorded. These intriguing results reveal a low level of interaction between introduced black rats and yelkouan shearwaters, which may have facilitated their long-term coexistence for thousands of years on some Mediterranean islands.

scholarly journals Prevalencia de leptospirosis en roedores sinantrópicos de la Ciudad de Corrientes, Argentina. Período mayo 2005–junio 2008

2008 ◽  
Vol 19 (2) ◽  
pp. 150 ◽  
Author(s):  
G. Marder ◽  
R. M. Ruiz ◽  
O. R. Bottinelli ◽  
H. A. Peiretti ◽  
L. Zorzo ◽  
...  
Keyword(s):  
Mus Musculus ◽  
Rattus Rattus

<p>La leptospirosis es una zoonosis causada por bacterias del género Leptospira sp., las cuales regularmente provocan brotes de la enfermedad en Argentina, donde el conocimiento de su epidemiología es incompleto. Los roedores (ratas y ratones sinantrópicos y silvestres) son los principales reservorios de leptospirosis en nuestro medio. El objetivo del estudio fue investigar la presencia de Leptospira sp. en roedores de la Ciudad de Corrientes, Argentina, así como la especie, sexo y edad de los ejemplares positivos a leptospirosis. Fueron capturados 101 especimenes, cuyo tejido renal fue utilizado para demostrar la presencia de Leptospira sp. mediante microscopio de campo oscuro a partir de cultivos de 15 días hasta un máximo de 6 meses. La tasa de positividad detectada fue de 58,4%, con una alta proporción de animales machos de la especie Rattus rattus. Solamente pudo capturarse un ejemplar de Mus musculus, que resultó infectado. Se concluye que la alta prevalencia de leptospirosis en roedores del área en estudio constituye un alarmante factor de riesgo de infección en animales domésticos y seres humanos.</p>

scholarly journals Sea-ice edge is more important than closer open water access for foraging Adélie penguins: evidence from two colonies

2020 ◽  
Vol 640 ◽  
pp. 215-230
Author(s):  
C Michelot ◽  
A Kato ◽  
T Raclot ◽  
K Shiomi ◽  
P Goulet ◽  
...  
Keyword(s):  
Sea Ice ◽  
Environmental Changes ◽  
Early Stage ◽  
Open Water ◽  
Gps Tracking ◽  
Ice Edge ◽  
Sea Ice Edge ◽  
Study Sites ◽  
The Impact ◽  
Adélie Penguins

Sentinel species, like Adélie penguins, have been used to assess the impact of environmental changes, and their link with sea ice has received considerable attention. Here, we tested if foraging Adélie penguins from 2 colonies in East Antarctica target the distant sea-ice edge or take advantage of closer open waters that are readily available near their colony. We examined the foraging behaviour of penguins during the incubation trips of females in 2016 and males in 2017, using GPS tracking and diet data in view of daily sea-ice data and bathymetry. In 2016-2017, sea-ice cover was extensive during females’ trips but flaw leads and polynyas were close to both study sites. Sea ice receded rapidly during males’ trips in 2017-2018. Despite close open water near both colonies in both years, females and males preferentially targeted the continental slope and the sea-ice edge to forage. In addition, there was no difference in the diet of penguins from both colonies: all penguins fed mostly on Antarctic krill and males also foraged on Antarctic silverfish. Our results highlight the importance of the sea-ice edge for penguins, an area where food abundance is predictable. It is likely that resource availability was not sufficient in closer open water areas at such an early stage in the breeding season. The behaviours displayed by the penguins from both colonies were similar, suggesting a common behaviour across colonies in Terre Adélie, although additional sites would be necessary to confirm this hypothesis.

scholarly journals Glodavci u skladištima poljoprivrednih proizvoda – štetnost i suzbijanje

2021 ◽  
Vol 44 (6) ◽  
pp. 42-48
Author(s):  
Dinka Grubišić ◽  
Ivan Juran ◽  
Mirjana Brmež ◽  
Maja Šurlog ◽  
Viktorija Sever ◽  
...  
Keyword(s):  
Mus Musculus ◽  
Rattus Norvegicus ◽  
Rattus Rattus

Glodavci su važni štetnici uskladištenih poljoprivrednih proizvoda. Uz zadovoljenje osnovnih prehrambenih potreba, štetne vrste u skladištima nalaze povoljne uvjete za razvoj i razmnožavanje te zaštitu od prirodnih neprijatelja. Najštetnije vrste glodavaca u skladištima Republike Hrvatske jesu štakori vrsta Rattus norvegicus i Rattus rattus te domaći miš Mus musculus. Osim što se hrane uskladištenim proizvodima, rasipaju ih, onečišćuju urinom, izmetom, dlakom i slinom, navedene vrste rezervoari su zoonozama koje utječu na zdravlje ljudi, te domaćih i divljih životinja. U Republici Hrvatskoj u populacijama sitnih glodavaca dokazani su uzročnici Lajmske borelioza, trihineloze, leptospiroze, Q groznice i hemoragijske vrućice s bubrežnim sindromom. Utvrđene su i višestruke infekcije glodavaca uzročnicima zoonoza. Redovito praćenje brojnosti glodavaca važno je u svrhu pravovremenog suzbijanja te smanjenja materijalnih gubitaka, ali i u svrhu sprječavanja pojave epidemija zoonoza. Uz preventivne mjere koje podrazumijevaju održavanje higijene prostora te održavanje infrastrukture, čime sprječavamo privlačenje i nastanjivanje glodavaca u skladištima, provodi se i kontinuirana deratizacija koja uključuje primjenu mehaničkih, fizikalnih i kemijskih mjera zaštite.

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