Local extinction and nestedness of small-mammal faunas in fragmented forest of central Victoria, Australia

1998 ◽  
Vol 4 (2) ◽  
pp. 122 ◽  
Author(s):  
J. N. Deacon ◽  
R. Mac Nally
Keyword(s):  
Small Mammals ◽  
Small Mammal ◽  
Native Species ◽  
Fragment Size ◽  
Timber Harvesting ◽  
Forest Fragments ◽  
Large Area ◽  
Fragmented Forest ◽  
Old Trees ◽  
Mammal Faunas

A survey of small mammals was undertaken in eight forest fragments of three sizes (2.5, 10 and 40 ha) and in five "pseudofragments" within a large area of State Forest. The latter were used to provide "reference" results against which the fragments could be compared. There was a paucity of dasyurid marsupials in fragments and pseudofragments, but arboreal "herbivores" (possums and a glider) were 7.5 times more abundant in fragments than in pseudofragments. The Short-beaked Echidna Tachyglossus aculeatus was recorded in both fragments and pseudofragments. All sites were impoverished, with a maximum of four native species of small mammals recorded at any one site, and six native species recorded overall. There was significant faunal "nesting" as a function of fragment size, with the small-mammal fauna of smaller fragments being subsets of larger fragments. The extant fauna in fragments appears to be a result of a sequence of local extinctions such that some species are more vulnerable to habitat loss, fragmentation and degradation and become locally extinct earlier than other, hardier species. The impoverishment within pseudofragments seems to be a function of broad-scale habitat modifications and especially timber harvesting, which maintains the forest as a dense array of small, pole-sized trees with few large, old trees. Several of the arboreal mammals are dependent on hollows found in larger trees, so the absence of the latter probably constrains the occurrence and density of the hollow users.

scholarly journals Small mammal glucocorticoid concentrations vary with forest fragment size, trap type, and mammal taxa in the Interior Atlantic Forest

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Sarah A. Boyle ◽  
Noé U. de la Sancha ◽  
Pastor Pérez ◽  
David Kabelik
Keyword(s):  
Atlantic Forest ◽  
Small Mammals ◽  
Acute Stress ◽  
Physiological Stress ◽  
Fragment Size ◽  
Hair Shaft ◽  
Forest Fragments ◽  
Forest Fragment ◽  
Trapping Methods ◽  
Free Ranging

AbstractSpecies that live in degraded habitats often show signs of physiological stress. Glucocorticoid hormones (e.g., corticosterone and cortisol) are often assessed as a proxy of the extent of physiological stress an animal has experienced. Our goal was to quantify glucocorticoids in free-ranging small mammals in fragments of Interior Atlantic Forest. We extracted glucocorticoids from fur samples of 106 small mammals (rodent genera Akodon and Oligoryzomys, and marsupial genera Gracilinanus and Marmosa) from six forest fragments (2–1200 ha) in the Reserva Natural Tapytá, Caazapá Department, Paraguay. To our knowledge, this is the first publication of corticosterone and cortisol levels for three of the four sampled genera (Akodon, Oligoryzomys, and Marmosa) in this forest system. We discovered three notable results. First, as predicted, glucocorticoid levels were higher in individuals living withing small forest fragments. Second, animals captured live using restraint trapping methods (Sherman traps) had higher glucocorticoid levels than those animals captured using kill traps (Victor traps), suggesting that hair glucocorticoid measures can reflect acute stress levels in addition to long-term glucocorticoid incorporation. These acute levels are likely due to urinary steroids diffusing into the hair shaft. This finding raises a concern about the use of certain trapping techniques in association with fur hormone analysis. Finally, as expected, we also detected genus-specific differences in glucocorticoid levels, as well as cortisol/corticosterone ratios.

Patterns and scale of habitat use in two temperate-zone, small mammal faunas

1984 ◽  
Vol 62 (8) ◽  
pp. 1540-1547 ◽  
Author(s):  
Douglas W. Morris
Keyword(s):  
Habitat Selection ◽  
Small Mammals ◽  
Species Distribution ◽  
Small Mammal ◽  
Habitat Preference ◽  
Species Interactions ◽  
Microhabitat Use ◽  
Microhabitat Selection ◽  
Extinction Probabilities ◽  
Mammal Faunas

Small mammals were livetrapped and habitat quantified in replicates of six macrohabitats in Alberta and in temporal replicates of four macrohabitats in Ontario, Canada. Similar patterns emerged in both locations. The relative abundances of small mammals depended upon macrohabitat; within macrohabitats, species differed significantly in microhabitat use. The patterns were dynamic and probably the result of habitat preference instead of species interactions. Macrohabitat differences may in part be outcomes of microhabitat selection, but are unlikely to be completely understood without superimposing colonization and extinction probabilities on habitat selection models. Field biologists must recognize both scales of habitat to interpret patterns of species distribution.

scholarly journals Habitat quality versus spatial variables as determinants of small mammal assemblages in Atlantic Forest fragments

2015 ◽  
Vol 97 (1) ◽  
pp. 253-265 ◽  
Author(s):  
Ana C. Delciellos ◽  
Marcus V. Vieira ◽  
Carlos E. V. Grelle ◽  
Priscilla Cobra ◽  
Rui Cerqueira
Keyword(s):  
Species Richness ◽  
Atlantic Forest ◽  
Habitat Quality ◽  
Small Mammals ◽  
Small Mammal ◽  
Habitat Structure ◽  
Fragment Size ◽  
Vegetation Density ◽  
Matrix Properties ◽  
Mammal Assemblages

Abstract Fragment size, isolation, and matrix properties have received considerable attention as predictors of species richness, abundance, and composition in habitat patches. However, measurements of habitat attributes or habitat quality are more directly related to the proximate effects of habitat fragmentation and may be more determinant of assemblages than traditional explanatory variables at local scales. We determine how habitat structure in fragments—a measure of habitat quality—compares to fragment size, isolation, and matrix properties as determinants of richness, abundance, and composition of non-volant small mammals in a fragmented landscape of Atlantic Forest. Small mammals were surveyed once in 25 fragments in the Macacu River watershed, Rio de Janeiro, Brazil, from 1999 to 2001 and 2005 to 2009. A total of 83 candidate models were formulated and compared by Akaike Information Criteria. Habitat structure was one of the main determinants of small mammal assemblages in fragments, as important as fragment isolation for species composition and climatic season for species richness. Rodents were more abundant in fragments with increased overstory and understory vegetation density and more fallen logs. The contrary pattern was found for overall species richness and for species of terrestrial habit, which were more abundant in fragments with more open forest: decreased overstory and understory vegetation density and less fallen logs. Habitat quality in fragments may be a more important determinant of assemblages of small mammals and other vertebrates than previously considered in landscape and land use studies. O tamanho e isolamento dos fragmentos e as propriedades da matriz têm recebido considerável atenção como preditores da riqueza, abundância e composição de espécies em manchas de habitat. Entretanto, medidas dos atributos do habitat ou da qualidade do habitat são mais diretamente relacionadas aos efeitos imediatos da fragmentação de habitat, e seriam mais determinantes das comunidades do que as variáveis explicativas tradicionais. Determinamos como a estrutura do habitat nos fragmentos—uma medida da qualidade do habitat—se compara ao tamanho e isolamento dos fragmentos, e às propriedades da matriz como determinantes da riqueza, abundância e composição de espécies de pequenos mamíferos não-voadores em uma paisagem fragmentada de Mata Atlântica. Os pequenos mamíferos foram amostrados uma vez em 25 fragmentos na Bacia do Rio Macacu, Rio de Janeiro, Brasil, de 1999 a 2001 e de 2005 a 2009. Um total de 83 modelos foram formulados e comparados utilizando o Critério de Informação de Akaike. A estrutura do habitat foi um dos principais determinantes das comunidades de pequenos mamíferos nos fragmentos de mata, tão importante quanto o isolamento entre fragmentos para a composição de espécies e os efeitos das estações climáticas sobre a riqueza de espécies. Os roedores foram mais abundantes nos fragmentos com estratificação vertical e sub-bosque mais densos e com maior presença de troncos caídos. O padrão contrário foi encontrado para a riqueza total de espécies e para espécies de hábito terrestre, que foram mais abundantes em fragmentos com estratificação vertical e sub-bosque menos densos e menor presença de troncos caídos. A qualidade do habitat em fragmentos pode ser determinante das comunidades de pequenos mamíferos e outros vertebrados, mais importante do que considerado previamente em estudos de paisagens e uso da terra.

scholarly journals Jungpleistozäne und altholozäne Fauna (Gastropoda und Mammalia) vom Euerwanger Bühl bei Greding (Fränkischer Jura)

1975 ◽  
Vol 26 (1) ◽  
pp. 155-180
Author(s):  
Wighart V. Koenigswald ◽  
Wolfgang Rähle
Keyword(s):  
Small Mammals ◽  
Small Mammal ◽  
Early Holocene ◽  
Age Dating ◽  
Southern Germany ◽  
Last Glacial ◽  
Mammal Faunas ◽  
The Last Glacial

Abstract. Small mammals and gastropod faunas out of a collapsed cave were quantitatively and qualitatively studied. One complex belongs to the last glacial, the others to the early holocene, or precicely Preboreal and early Boreal according to C14 age dating. Early holocene small mammal faunas in southern Germany are represented by Pitymys subterraneus as well as pleistocene relict forms. The gastropod fauna contains Zebrina detrita in a typical Discus ruderatus / Nesovitrea petronella fauna.

scholarly journals Multi-scale determinants of small mammal and lizard dimensions of diversity across Amazonian insular forest fragments

2021 ◽  
Author(s):  
Ana Filipa Palmeirim ◽  
Fabio Farneda ◽  
Marcus Vinicius Vieira ◽  
Carlos A. Peres
Keyword(s):  
Habitat Loss ◽  
Small Mammals ◽  
Small Mammal ◽  
Habitat Type ◽  
Forest Area ◽  
Small Island ◽  
Forest Fragments ◽  
Species Identity ◽  
Hydropower Development ◽  
Β Diversity

Abstract Context Hydropower development is one of the primary drivers of habitat loss and insular fragmentation. Yet, studies quantifying such effects on biodiversity are mostly limited to taxonomic metrics, often overlooking species identity and their functional and phylogenetic roles. Objectives We examined taxonomic, functional and phylogenetic responses to habitat loss and insular fragmentation of small mammals and lizards within (α) and between sites (β). Methods Both taxa were surveyed across 25 islands within the Balbina Hydroelectric Reservoir, and adjacent continuous forest, in Central Amazonia. Each dimension of diversity was related to spatial and habitat variables. We also examined functional composition using community-weighted mean trait values, and community redundancy using functional uniqueness. β-diversity was partitioned into their richness (βrich) and replacement (βrepl) components. Results Functional and phylogenetic α−diversities of both taxa mirrored the taxonomic dimension, all of which increased with forest area. Individual small mammal (body mass and matrix tolerance), and lizard traits (heliothermic mode and habitat type) were also predicted by forest area. For both taxa, species functional uniqueness decreased with forest area, and all dimensions of β-diversity were predominantly partitioned in βrich. Conclusions The environmental filter created by forest area resulted in the low conservation value associated with small forest islands, only occupied by a small set of species comprised by generalist lizards and matrix-tolerant small mammals. On the other side, large forest sites ensured ecosystem resilience to disturbance. To maintain ecosystem integrity, creating a myriad small island over large expanses of floodwaters should be avoided in future hydropower development.

scholarly journals Habitat associations of small mammals in southern Brazil and use of regurgitated pellets of birds of prey for inventorying a local fauna

2007 ◽  
Vol 67 (4) ◽  
pp. 619-625 ◽  
Author(s):  
DR. Scheibler ◽  
AU. Christoff
Keyword(s):  
Small Mammals ◽  
Small Mammal ◽  
Rattus Rattus ◽  
Habitat Associations ◽  
Native Forest ◽  
Forest Fragments ◽  
Tyto Alba ◽  
Southern Brazil ◽  
Mammal Species ◽  
Barn Owls

We inventoried terrestrial small mammals in an agricultural area in southern Brazil by using trapping and prey consumed by Barn Owls (Tyto alba) and White-tailed Kites (Elanus leucurus). Small mammals were trapped in three habitat types: corn fields, uncultivated fields ("capoeiras"), and native forest fragments. A total of 1,975 small mammal specimens were trapped, another 2,062 identified from the diet of Barn Owls, and 2,066 from the diet of White-tailed Kites. Both trapping and prey in the predators' diet yielded 18 small mammal species: three marsupials (Didelphis albiventris, Gracilinanus agilis, and Monodelphis dimidiata) and 15 rodents (Akodon paranaensis, Bruceppatersonius iheringi, Calomys sp., Cavia aperea, Euryzygomatomys spinosus, Holochilus brasiliensis, Mus musculus, Necromys lasiurus, Nectomys squamipes, Oligoryzomys nigripes, Oryzomys angouya, Oxymycterus sp.1, Oxymycterus sp.2, Rattus norvegicus, and Rattus rattus (Linnaeus, 1758)). The greatest richness was found in the uncultivated habitat. We concluded that the three methods studied for inventorying small mammals (prey in the diet of Barn Owls, White-tailed Kites, and trapping) were complementary, since together, rather than separately, they produced a better picture of local richness.

scholarly journals Forest area predicts all dimensions of small mammal and lizard diversity in Amazonian insular forest fragments

2021 ◽  
Author(s):  
Ana Filipa Palmeirim ◽  
Fábio Z. Farneda ◽  
Marcus Vinícius Vieira ◽  
Carlos A. Peres
Keyword(s):  
Small Mammals ◽  
Small Mammal ◽  
Multiple Scales ◽  
Habitat Type ◽  
Forest Area ◽  
Integrative Approach ◽  
Dispersal Ability ◽  
Forest Fragments ◽  
Hydropower Development ◽  
Β Diversity

Abstract Context Although hydropower development is one of the primary drivers of habitat loss and insular fragmentation, its impacts on species identity and their functional and phylogenetic roles have often been overlooked. Objectives Here we use an integrative approach, considering taxonomic, functional and phylogenetic dimensions at multiple scales, to understand the processes underlying species (dis)assembly of two taxa exhibiting relatively low dispersal ability: small mammals and lizards. Methods We surveyed 26 islands within the Balbina Hydroelectric Reservoir, and adjacent continuous forest, in Central Amazonia. Each dimension of diversity was related to spatial and habitat variables. We also examined functional composition using community-weighted mean trait values, and community redundancy using functional uniqueness. β-diversity was partitioned into their richness (βrich) and replacement (βrepl) components. Results Functional and phylogenetic α-diversities of both taxa mirrored the taxonomic dimension, all of which increased with forest area. Individual small mammal (body mass and matrix tolerance), and lizard traits (body length, heliothermic mode and habitat type) were also predicted by forest area. For both groups, functional uniqueness decreased with forest area, and all dimensions of β-diversity were predominantly partitioned in βrich. Conclusions The environmental filter created by forest area resulted in the low conservation value associated with small forest islands, only occupied by a small set of species comprised by generalist lizards and matrix-tolerant small mammals. On the other side, large forest sites ensured ecosystem resilience to disturbance. To maintain ecosystem integrity, creating myriad small islands over large expanses of floodwaters should be avoided in future hydropower development.

scholarly journals Effects of land use, habitat characteristics, and small mammal community composition on Leptospira prevalence in northeast Madagascar

2020 ◽  
Vol 14 (12) ◽  
pp. e0008946
Author(s):  
James P. Herrera ◽  
Natalie R. Wickenkamp ◽  
Magali Turpin ◽  
Fiona Baudino ◽  
Pablo Tortosa ◽  
...  
Keyword(s):  
Land Use ◽  
Introduced Species ◽  
Community Composition ◽  
Relative Abundance ◽  
Small Mammal ◽  
Native Species ◽  
Forest Fragments ◽  
Mammal Species ◽  
Small Mammal Community ◽  
Mammal Community

Human activities can increase or decrease risks of acquiring a zoonotic disease, notably by affecting the composition and abundance of hosts. This study investigated the links between land use and infectious disease risk in northeast Madagascar, where human subsistence activities and population growth are encroaching on native habitats and the associated biota. We collected new data on pathogenic Leptospira, which are bacteria maintained in small mammal reservoirs. Transmission can occur through close contact, but most frequently through indirect contact with water contaminated by the urine of infected hosts. The probability of infection and prevalence was compared across a gradient of natural moist evergreen forest, nearby forest fragments, flooded rice and other types of agricultural fields, and in homes in a rural village. Using these data, we tested specific hypotheses for how land use alters ecological communities and influences disease transmission. The relative abundance and proportion of exotic species was highest in the anthropogenic habitats, while the relative abundance of native species was highest in the forested habitats. Prevalence of Leptospira was significantly higher in introduced compared to endemic species. Lastly, the probability of infection with Leptospira was highest in introduced small mammal species, and lower in forest fragments compared to other habitat types. Our results highlight how human land use affects the small mammal community composition and in turn disease dynamics. Introduced species likely transmit Leptospira to native species where they co-occur, and may displace the Leptospira species naturally occurring in Madagascar. The frequent spatial overlap of people and introduced species likely also has consequences for public health.

Relative use of contiguous and fragmented boreal forest by red squirrels (Tamiasciurus hudsonicus)

2000 ◽  
Vol 78 (3) ◽  
pp. 359-365 ◽  
Author(s):  
Erin Bayne ◽  
Keith Hobson
Keyword(s):  
Forest Fragmentation ◽  
Relative Abundance ◽  
Agricultural Landscape ◽  
Fragment Size ◽  
Tamiasciurus Hudsonicus ◽  
Forest Fragments ◽  
Red Squirrel ◽  
Red Squirrels ◽  
Fragmented Forest ◽  
Forest Habitats

We examined whether forest fragmentation by agriculture influenced the abundance of North American red squirrels (Tamiasciurus hudsonicus) in the southern boreal mixedwood forest of Saskatchewan. During the summers of 1995 and 1997, we determined the relative abundance of red squirrels in 43 forest fragments ranging in size from 0.2 to 82 ha and in 15 sites in nearby contiguous forest. Relative abundance was determined using acoustic point count surveys, in which all squirrel vocalizations were recorded. Within the fragmented agricultural landscape, we found that red squirrel abundance increased slightly with forest-fragment size, whereas the abundance of red squirrels was negatively correlated with the amount of forest cover within 1 km of a site. We also compared squirrel abundance in forest fragments with that in contiguous forest and found that red squirrels were significantly more abundant in forest fragments than in contiguous forest. We speculate that changes in dispersal patterns in fragmented forest habitats, higher squirrel survival in forest fragments, and differences in diet between contiguous and fragmented forest habitats contributed to this pattern. Our results suggest that forest fragmentation may not be particularly detrimental to habitat generalists like the red squirrel. However, an increased abundance of red squirrels in forest fragments may result in negative effects on other species, such as forest songbirds.

Microhabitat structure and food availability modelling a small mammal assemblage in restored riparian forest remnants

Mammalia ◽  
2018 ◽  
Vol 82 (4) ◽  
pp. 315-327
Author(s):  
Matheus R.J. Corrêa ◽  
Yuri M. Bellagamba ◽  
Adriele P. de Magalhães ◽  
Joice P.V. Martins ◽  
Antônio J. do R. Cruz ◽  
...  
Keyword(s):  
Food Availability ◽  
Small Mammals ◽  
Small Mammal ◽  
Riparian Forest ◽  
Foraging Strategies ◽  
Similar Species ◽  
Forest Fragments ◽  
Mammal Species ◽  
Forest Remnants ◽  
Microhabitat Structure

Abstract Small mammal populations respond to environmental changes in secondary riparian forest remnants in different ways, depending on the influences of biotic and abiotic variables. The present study evaluated how habitat/microhabitat structure and food availability influence small mammal assemblages in restored riparian forest remnants. Pitfall traps disposed in three linear transects were used to collect small mammals during 9 months of field work. General linear models were built to test the hypothesis that microhabitat structure (litter biomass and type – leaves and branches) and food availability (richness of zoochoric tree species and arthropods) influence species richness and abundance of small mammals. Three hundred and eighty-two individuals belonging to 14 species were captured. Biomass and type of litter (leaves or branches) provided greater structural to microhabitats, allowing the coexistence of morphologically similar species. Besides, food availability influenced foraging strategies of marsupials, forcing them to use the forest floor when zoochoric plants were rare. Thus, litter structure and food availability, allowing spatial segregation of the small mammal species using the forest fragments. We concluded that the maintenance of small mammals and their ecosystem services in restored riparian forests are dependent on habitat structure and food availability, thus, litter and zoochoric plants should be conserved in riparian forest fragments, especially those reforested.

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