Preliminary Results of the Research on Biology, Ecology and Conservation of the Chelonoidis chilensis (Sensu Lato) Gray, 1870 Tortoise in Argentina.

Buenos Aires: Proyecto Tortugas, Fundación Vida Silvestre Argentina.
PDF, 45 Seiten, 8 Anhänge mit Grafiken.

waller-biblio

Freigegeben in W
Samstag, 11 Februar 2023 09:48

WIESEL, I. (2006)

Predatory and Foraging Behaviour of Brown Hyenas (Parahyaena brunnea (Thunberg, 1820)) at Cape Fur Seal (Arctocephalus pusillus pusillus Schreber, 1776) Colonies.

Diss. Uni Hamburg. 210 Seiten.

Volltext: https://ediss.sub.uni-hamburg.de/bitstream/ediss/1584/1/IWDissertation.pdf

Conclusions:

The predatory and foraging behaviour of brown hyenas (Parahyaena brunnea) was observed at mainland Cape fur seal (Arctocephalus pusillus pusillus) breeding colonies in the southern Namib Desert. The objectives of this study were to

(1) assess the availability, condition and accessibility of seals for brown hyenas,
(2) evaluate the importance of the coast for brown hyena abundance, movement and energy budget,
(3) determine factors influencing the foraging related time budget of brown hyenas,
(4) assess feeding preferences, and
(5) examine the consumption of prey.

Behavioural observations were conducted at the Van Reenen Bay seal colony and seal pup mortality data was recorded at the Wolf Bay seal colony.
GPS collars were fitted on coastal brown hyenas to determine their movement. Live seal pups were available for brown hyenas all year round, but their increasing size, mobility and activity, as well as the attendance pattern of adult females may influence the brown hyena’s foraging behaviour. Many dead pups were available to scavenge during the pupping season and represented an easy and safe way to obtain food.

In general, predators and prey are mutually influenced by each others behaviours. In Chapter 4 the anti-predator strategies of Cape fur seals towards brown hyenas were reviewed and assessed with regard to their influence on the hyena’s foraging strategies. Although Cape fur seals showed a near complete lack of anti-predator behaviour, the predator-prey system is possibly donor-controlled (Chapter 5) and the usual depensatory effect on prey populations that face novel or exotic predators is not expected (see Sinclair et al. 1998). The numerical response of predators to increased prey numbers as predicted by Holling (1959, 1965) could not be seen in this study (Chapter 5), and seasonality in the availability of seal pups, therefore, may limit brown hyena population growth, and may contribute to the maintenance of large home ranges despite localised food sources. However, coastal brown hyenas’ daily movements were less than that of inland ones, they have a lower field metabolic rate, and hence may consume less food.

Brown hyenas preferred to kill seal pups despite the availability of carrion (Chapter 6). The predation rate was unrelated to carrion availability, but the absolute number of kills was positively correlated to seal pup density. Increasing  seal pup density led to an increase in brown hyena capture rate and hunting efficiency. Furthermore the overabundance of easy and vulnerable prey led to surplus kills. However, brown hyenas foraged opportunistically by scavenging, killing and caching seal pups in proportion to their occurrence at the colony (Chapter 7 and 8), and hence, caused an additional impact on seal pup mortality by not only choosing the doomed surplus. The killing of seal pups seemed to be unrelated to hunger, and surplus killing occurred throughout the study period. Brown hyenas preferred to consume larger and heavier prey, but a large proportion of the brown hyena’s prey was only partially consumed (Chapter 8). Selectivity increased with seal pup density, and feeding and handling times per prey item were reduced. Brown hyenas showed a preference for brain tissue, and the consumption of brain tissue may quickly satisfy the brown hyena’s metabolic requirements, or may be important to keep a positive water balance. Although black-backed jackals (Canis mesomelas) outnumber brown hyenas and are their main competitors at seal colonies, they did not influence the brown hyena’s foraging strategy.

Brown hyenas, therefore, behave opportunistically regarding their feeding preferences and optimally regarding the consumption of seals. Seal pup density influences the brown hyena’s predatory and foraging behaviour, and seasonality in seal availability may limit brown hyena abundance and influence their movement patterns. Future observations of foraging brown hyenas outside the pupping season and at night could yield additional interesting information about adaptations in predatory and foraging behaviour to changes in seal behaviour, abundance and attendance.

wiesel-biblio

WIESEL, I. (2006)

Predatory and Foraging Behaviour of Brown Hyenas (Parahyaena brunnea (Thunberg, 1820)) at Cape Fur Seal (Arctocephalus pusillus pusillus Schreber, 1776) Colonies.

Diss. Uni Hamburg. 210 Seiten.

Volltext: https://ediss.sub.uni-hamburg.de/bitstream/ediss/1584/1/IWDissertation.pdf 

Conclusions

The predatory and foraging behaviour of brown hyenas (Parahyaena brunnea) was observed at mainland Cape fur seal (Arctocephalus pusillus pusillus)

breeding colonies in the southern Namib Desert. The objectives of this study were to

(1) assess the availability, condition and accessibility of seals for brown hyenas,

(2) evaluate the importance of the coast for brown hyena abundance, movement and energy budget,

(3) determine factors influencing the foraging related time budget of brown hyenas,

(4) assess feeding preferences, and

(5) examine the consumption of prey.

Behavioural observations were conducted at the Van Reenen Bay seal colony and seal pup mortality data was recorded at the Wolf Bay seal colony.

GPS collars were fitted on coastal brown hyenas to determine their movement. Live seal pups were available for brown hyenas all year round, but their

increasing size, mobility and activity, as well as the attendance pattern of adult females may influence the brown hyena’s foraging behaviour. Many dead pups

were available to scavenge during the pupping season and represented an easy and safe way to obtain food.

In general, predators and prey are mutually influenced by each others behaviours. In Chapter 4 the anti-predator strategies of Cape fur seals towards

brown hyenas were reviewed and assessed with regard to their influence on the hyena’s foraging strategies. Although Cape fur seals showed a near complete

lack of anti-predator behaviour, the predator-prey system is possibly donor-controlled (Chapter 5) and the usual depensatory effect on prey populations that

face novel or exotic predators is not expected (see Sinclair et al. 1998). The numerical response of predators to increased prey numbers as predicted by

Holling (1959, 1965) could not be seen in this study (Chapter 5), and seasonality in the availability of seal pups, therefore, may limit brown hyena population

growth, and may contribute to the maintenance of large home ranges despite localised food sources. However, coastal brown hyenas’ daily movements were

less than that of inland ones, they have a lower field metabolic rate, and hence may consume less food.

Brown hyenas preferred to kill seal pups despite the availability of carrion (Chapter 6). The predation rate was unrelated to carrion availability, but the

absolute number of kills was positively correlated to seal pup density. Increasing  seal pup density led to an increase in brown hyena capture rate and hunting

efficiency. Furthermore the overabundance of easy and vulnerable prey led to surplus kills.

However, brown hyenas foraged opportunistically by scavenging, killing and caching seal pups in proportion to their occurrence at the colony (Chapter 7

and 8), and hence, caused an additional impact on seal pup mortality by not only choosing the doomed surplus. The killing of seal pups seemed to be unrelated to hunger, and surplus killing occurred throughout the study period. Brown hyenas preferred to consume larger and heavier prey, but a large proportion of the brown hyena’s prey was only partially consumed (Chapter 8). Selectivity increased with seal pup density, and feeding and handling times per prey item were reduced.

Brown hyenas showed a preference for brain tissue, and the consumption of brain tissue may quickly satisfy the brown hyena’s metabolic requirements, or

may be important to keep a positive water balance. Although black-backed jackals (Canis mesomelas) outnumber brown hyenas and are their main competitors at seal colonies, they did not influence the brown hyena’s foraging strategy.

Brown hyenas, therefore, behave opportunistically regarding their feeding preferences and optimally regarding the consumption of seals. Seal pup density

influences the brown hyena’s predatory and foraging behaviour, and seasonality in seal availability may limit brown hyena abundance and influence their

movement patterns. Future observations of foraging brown hyenas outside the pupping season and at night could yield additional interesting information about adaptations in predatory and foraging behaviour to changes in seal behaviour, abundance and attendance.

Freigegeben in W

Kupferrote Springaffen (Plecturocebus cupreus)

Zeitschrift des Kölner Zoos 65(2): 49-62.

Volltext (PDF)

Zusammenfassung:

Wir berichten über Ergebnisse von Freilandstudien an Kupferroten Springaffen (Plecturocebus cupreus) an der Estación Biológica Quebrada Blanco (EBQB), einer Forschungsstation im nordöstlichen peruanischen Amazonastiefland. Diese Springaffen können aufgrund ihrer Nahrungszusammensetzung als frugivor-faunivor charakterisiert werden. Sie leben in Familiengruppen von 2-6 Mitgliedern. Die Beziehungen zwischen dem Elternpaar sind gekennzeichnet durch einen größeren Beitrag des Weibchens zur sozialen Fellpflege und zur Aufrechterhaltung der räumlichen Nähe. Männchen sind hingegen die hauptsächlichen oder einzigen Träger der Jungtiere. Nach den bisherigen genetischen Befunden sind die Kupferroten Springaffen monogam, d. h. Jungtiere stammen von Männchen eines Paares ab, Vaterschaften außerhalb des Paares wurden nicht gefunden. Außerdem übernehmen sie bei Begegnungen mit potentiellen Raubfeinden und mit Nachbargruppen aktiver als die Weibchen. Springaffen zeigen eine ungewöhnliche Assoziation mit Mistkäfern. Wir enden mit einem Ausblick auf offene Fragestellungen.

heymann-biblio

Freigegeben in H
Donnerstag, 27 Januar 2022 15:50

WILKINS, K., PEJCHAR, L. & GARVOILLE, R. (2019)

Ecological and social consequences of bison reintroduction in Colorado.

Conservation Science and Pracfice 1(2). DOI: 10.1002/csp2.9.

Abstract:

Bison were instrumental in shaping North America's Great Plains. Interest in restoring this iconic species and their ecological role in grassland ecosystems is rapidly gaining momentum. To evaluate the potential for bison to enhance habitat quality for wildlife and catalyze public engagement in grassland conservation, we assessed both the ecological and social effects of a recent bison reintroduction (2015) to northern Colorado. Specifically, we explored the effect of bison reintroduction on: (a) bird density and habitat use, (b) mammal habitat use, (c) vegetation composition and structure, and (d) visitor connectedness, known as place attachment, to a shortgrass prairie. We predicted that bison reintroduction would reduce cover and height of some grasses and shrubs, which would increase density and habitat use for obligate shortgrass prairie birds, and increase habitat use for coyote and lagomorphs. In addition, we predicted that visitors would express stronger place attachment to this grassland once bison were reintroduced. To measure ecological and social responses, we surveyed birds, mammals, and plants; and conducted structured visitor surveys before and after bison reintroduction. We found few short-term effects of bison on grassland bird density and habitat use, mammal habitat use, and vegetation composition and structure. However, we measured a significant increase in visitor place attachment to the grassland site 1 year after bison reintroduction. Our results suggest that a new bison reintroduction may have immediate positive benefits for connecting people to conservation, and that the ecological and social effects may unfold over different time scales. We recommend that future bison reintroduction efforts monitor ecological and social outcomes to advance reintroduction biology.

wilkins-biblio

Freigegeben in W
Sonntag, 09 Januar 2022 10:50

SCHULTE, U. (2007)

Beobachtungen zur Hybridisierung zwischen Ctenosaura similis (Gray, 1831) und Ctenosaura bakeri Stejneger 1901 auf Utila, Honduras. 

Elaphe N.F. 15: 55-59.

Zusammenfassung:

Die honduranische Karibikinsel Utila ist der einzige bekannte Ort der Welt, an dem drei Großleguanarten vorkommen. Währenddem Iguana iguana rhinolopha primär die Feuchtwälder bewohnt und Ctenosaura bakeri exklusiv die schattigen Mangrovensümpfe besiedelt, bevorzugt Ctenosaura similis semiaride bis aride Lebensdräume mit starker Sonneneinstrahlung. Trotz dieser ökologischen Trennung wurde bereits in der Vergangenheit von fertilen Hybriden zwischen C. similis und C. bakeri berichtet. Neben der Beschreibung eines möglichen Hybridgürtels mit beonbachteten potenziellen Bastarden, wird die ökologische Anpassungs- und Ausbreitungsfähigkeit von C. similis aufgezeigt.

schulte-biblio

Freigegeben in S

Habitat Determinants of the Threatened Sahel Tortoise Centrochelys sulcata At Two Spatial Scales.

Herpetological Conservation and Biology 12(2): 402–409.

The African Spurred Tortoise (Centrochelys sulcata), the second largest tortoise species in the world, is threatened with extinction because of a variety of threats, including habitat loss. Because details of habitat use for this species have not been published for wild populations of this species, we conducted this study to qualify and quantify habitat selection at two spatial scales in Burkina Faso and Niger (West Africa). Tortoises were active above-ground almost exclusively in August, during the peak of the wet season. We surveyed seven potential habitat types but the majority of adult and juvenile tortoises were observed in only two, dry river beds (locally named kori) and stabilized dunes. We used GIS (Geographical Information System) to map the known distribution of the African Spurred Tortoise in both countries in relation to the availability of kori. The habitat preference of African Spurred Tortoises widely overlaps with the occurrence of kori (and not permanent rivers or other water bodies) in the landscape. We discuss the biological and ecological reasons explaining the results, as well as the conservation consequences.

petrozzi-biblio

Freigegeben in P

Masoala - Das Auge des Waldes - Eine Überlebensstrategie für den Regenwald in Madagaskar.

144 Seiten mit zahlreichen Farbfotos von Priska Ketterer
Th. Gut Verlag, Stäfa. ISBN13: 978-3-85717-155-0

Klappentext:

Madagaskar ist einmalig bezüglich seiner Fauna und Flora, die in den Regenwäldern von Masoala ihren Höhepunkt findet. 1990 erliess die Regierung Madagaskars einen Aktionsplan zur Erhaltung der Umwelt. Um die Zerstörung dieses Naturschutzgebietes zu verhindern, entschlossen sich der Zoo Zürich sowie die Wildlife Conservation Society und ihre Partner, mit dem madagassischen Volk zusammen zu arbeiten. Die 2003 eingeweihte Masoalahalle im Zürcher Zoo ist ein Schaufenster für Madagaskar in Europa. Die beispielhafte Anlage basiert auf einem modernen Zoo-Naturschutzkonzept und ist Grundlage für eine enge Zusammenarbeit mit einem Naturschutzprojekt in der Wildnis. Mit dem Masoala Regenwald ist nicht nur eine moderne Zooanlage entstanden, sondern auch eine einmalige Sehenswürdigkeit, die weit über die Landesgrenzen hinaus auf Interesse stößt.

rübel-biblio

Freigegeben in R

Habitat Degradation and Seasonality Affect Physiological Stress Levels of Eulemur collaris in Littoral Forest Fragments.

PLoS ONE 9(9): e107698. https://doi.org/10.1371/journal.pone.0107698

Abstract:

The littoral forest on sandy soil is among the most threatened habitats in Madagascar and, as such, it represents a hot-spot within a conservation hot-spot. Assessing the health of the resident lemur fauna is not only critical for the long-term viability of these populations, but also necessary for the future re-habilitation of this unique habitat. Since the Endangered collared brown lemur, Eulemur collaris, is the largest seed disperser of the Malagasy south-eastern littoral forest its survival in this habitat is crucial. In this study we compared fecal glucocorticoid metabolite (fGCM) levels, a measure of physiological stress and potential early indicator of population health, between groups of collared brown lemurs living in a degraded forest fragment and groups occurring in a more preserved area. For this, we analysed 279 fecal samples collected year-round from 4 groups of collared brown lemurs using a validated 11-oxoetiocholanolone enzyme immunoassay and tested if fGCM levels were influenced by reproductive stages, phenological seasons, sex, and habitat degradation. The lemurs living in the degraded forest had significantly higher fGCM levels than those living in the more preserved area. In particular, the highest fGCM levels were found during the mating season in all animals and in females during gestation in the degraded forest. Since mating and gestation are both occurring during the lean season in the littoral forest, these results likely reflect a combination of ecological and reproductive pressures. Our findings provide a clear indication that habitat degradation has additive effects to the challenges found in the natural habitat. Since increased stress hormone output may have long-term negative effects on population health and reproduction, our data emphasize the need for and may add to the development of effective conservation plans for the species.

balestri-biblio

Freigegeben in B
Dienstag, 09 März 2021 12:26

PEGEL, M., THOR G. et al. (2000)

Rehwildprojekt Borgerhau: Untersuchungen zur Ökologie einer freilebenden Rehwildpopulation.

Wildforschung in Baden-Württemberg Band 5.

143 Seiten. Hrsg: Staatlichen Lehr-und Versuchsanstalt AulendorfWildforschungsstelle

Volltext: https://fortbildung-lazbw.lgl-bw.de/lazbw/webbasys/download/Shop/Rehwildbericht%20Borgerhau.pdf

Kitzrate und frühe Kitzsterblichkeit(Zitat aus Zusammenfassung)

Pro  im  Herbst  vorhandener  adulter  Geiß  wurden im Mittel 1,44 Kitze beobachtet. Diese Kitzrate  schwankte  witterungsbedingt in den einzelnen Jahren zwischen 0,93 und 1,63. Auf den gesamten Untersuchungszeitraum  bezogen wurden  am 1. September 14%  der Geißen  ohne Kitz festgestellt, 31%  hatten ein Kitz, 52% zwei Kitze und 3% drei Kitze. Die  frühe Kitzsterblichkeit (Geburt bis  1. September)  wurde nach  zwei Methoden  eingeschätzt (nach  ergleich zwischen potentieller und realisierter Kitzrate sowie nach der  Wiederbeobachtungsrate markierter Kitze). Es ergaben sich die Werte 24%  bzw. 22% als Mittel für den Untersuchungszeitraum. Markierte Kitze unterlagen keiner erhöhten Sterblichkeit.

pegel-biblio

Freigegeben in P

L'écologie de la mone de Campbell (Cercopithecus campbelli lowei) en Côte d'Ivoire.

La Terre et la Vie 1969/2: 135-163.

Summary:

Lowe's guenon (Cercopithecus campbelli lowei) is still one of the commonest monkeys of the Ivory Coast. It is found in all forest types, from old mature rain forest to secondary growth. Although these monkeys spend most of their time in the middle and lower layers of the forest, they occasionally visit the canopy or descend to the ground. The various types of locomotion are described and illustrated. Most of the detailed information obtained on the ecology and behaviour of the Lowe's guenon is based upon observations made from 1967 to 1969 on a wild troop living on the grounds of the Swiss Research Center, at Adiopodoumé. The history of this group has been recorded since 1964. Comparative observations were made on various wild troops in western Ivory Coast, and on 2 free ranging pets at the Lamto field station in 1967. The home range of the Adiopodoumé troop is small, covering about 3 hectares. The monkeys use the same sleeping trees for long pcriods of time and regularly visit fruit trees and places where they are given bananas. There is no rigid daily time schedule, and most of the home range is visited every day. The wild troop does not allow adult foreign conspecifics to settle on its territory, but a one year old male infant was accepted in February 1969. The staple food of the Lowe's guenon consists of fruits, flowers and leaves. Thirty two species of food plants are recorded. The monkeys are also very fond of insects, which they activcly hunt both in trces and on the ground. Insect hunting is selective, some unpalatable species being deliberately rejected. Water is licked from leaves and branches, or scooped out of tree holes. Breeding is seasonal, all infants bcing born between mid­November and mid-January, at the very end of the long rains and the beginning of the dry season. Thus the females appear ta conceive during the annual peak in rainfall and during the annual decline in temperature. The social structure of the troop is described. Although it includes more males than females, the Adiopodoumé troop is a «one male group», centered around the adult male. He acts as a leader and spends a great deal of time watching. The «warning bark» is his prerogative. Unlike mature females who readily act as «aunts», the adult male does not show interest in infants, even newborn ones, and juveniles. However he allows them to play close to him. Subadult males are bolder and more inquisitive than any other troop member. Juveniles and infants are very active players. No overt and rigid social hierarchy exists within the troop, although in certain circumstances younger individuals give way ta older ones. Early in 1969 a splitting of the group was observed. It took place progressively and quietly. In February, two males, 4 and 3 years old, and one 4 year old female, began to separatc from the rest of the troop during the day, returning to the traditional sleeping trees at night. They left the troop's home-range for good around the lst of March. Lowe's guenon often associates with other species of Cercopithecus (C. petaurista mainly) and Colobines (Colobus polykomos and C. badius). These mixed troops are more than chance aggregations of different species on the same food trees. In Lamto, the two free ranging male Cercopithecus campbelli lowei reacted immediately to the distress calls of a young female C. petaurista living with them, and would come to her rescue if she was in danger. Interactions with other Vertebrates are described. Reactions to soaring birds of prey are not stereotyped: in Adiopodoumé, the monkeys were not afraid of the common black kites, whereas an approaching buzzard sent them «diving» into thick foliage. Play interactions were observed with roosting hornbills, and even a pet mongoose. Breeding periodicity, which permits an eventual use of seasonal food surpluses, and the ability to descend to the ground and cross open spaces, might « pre-adapt » this forest monkey to life in wooded savannas. These two characteristics certainlv help one to understand the wide range of Lowe's guenon and its ability to live in the forest-savanna boundary.

bourilere-biblio

Freigegeben in B
Seite 1 von 12
© Peter Dollinger, Zoo Office Bern hyperworx