Burrows Of Small Mammals Research Articles

Effects of Conspecifics on the Burrow Occupancy Behavior of Spotted Salamanders (Ambystoma maculatum)

Abstract The spotted salamander (Ambystoma maculatum) is a pool-breeding species thought to depend on small mammal burrows for survival in terrestrial habitats. We investigated burrow occupancy patterns using laboratory and field experiments where salamanders were housed alone or in pairs, in arenas with either one or two burrows. In the single-burrow field experiment, intruders were significantly less likely than residents to occupy burrows, and the probability of burrow occupancy declined following nighttime rain. However, spotted salamanders frequently co-occupied burrows (mean burrow co-occupancy rate, 59%). In the single-burrow laboratory experiment, mean burrow occupancy rate was 98%, both when salamanders were housed alone and in pairs. However, salamanders housed in pairs with two burrows co-occupied burrows less frequently than expected by chance, and greater size disparity was associated with lower burrow co-occupancy rates. Our results suggest that spotted salamanders may often fail to effectiv...

Influence of abundance of small-mammal burrows and conspecifics on the density and distribution of spotted salamanders (Ambystoma maculatum) in terrestrial habitats

Spotted salamander (Ambystoma maculatum) distributions were studied within eighteen 272-m2 field enclosures in upland deciduous forest adjacent to two breeding ponds. The enclosures were subsequently used in experiments involving (i) removal of small-mammal burrows to determine if burrow abundance influenced salamander density and (ii) manipulation of salamander densities to determine if increased density was associated with decreased growth, fecundity, or probability of re-emerging to breed. Mean density of salamanders wintering in enclosures <65 m from the breeding ponds was 1.0/100 m2 (SD = 1.1/100 m2, n = 17, range = 0–4.0/100 m2). Density declined as distance to the nearest breeding pond increased, and the sex ratio was skewed sharply toward males (8:1) wintering close (<65 m) to the pond but not farther from the pond (1:1). Males residing within the enclosures weighed more than males wintering farther from the breeding ponds. Migrating salamanders were over 3 times more likely to leave burrow-removal plots than control plots prior to the summer inactive period. Salamanders housed at high density (15/enclosure) were less likely to re-emerge to breed than were salamanders housed at low density (5/enclosure), but we observed no effects on growth or fecundity. Results suggest that conspecific distribution and burrow availability might affect the density of spotted salamanders within terrestrial habitats.

Soil resource heterogeneity in the Mojave Desert

Heterogeneity of soil resources was investigated in the Mojave Desert to better understand spatial variability of soil attributes in a Larrea tridentata–Ambrosia dumosa community. Six soil samples were collected at each of eight microsites, with this sampling scheme replicated for three sites that were 0·7 km apart on a 10-km long bajada. The eight microsites were: five different shrub types (individual shrubs of L. tridentata, individual shrubs of Lycium pallidum , individual shrubs of A. dumosa, mixtures of shrub species with small mammal burrows, and mixtures of shrubs without small mammal burrows), a grass microsite (around individual plants of the tussock grass Pleuraphis rigida), and two microsites without perennial vegetation (one within small washes and the other within the interspace between perennial plants). Fifteen soil parameters were assessed, and all were found to differ among microsites. Nutrients were assessed as the pools extractable by vegetation. Mineral nutrients except for Ca, organic matter, and litter were higher in soils collected from shrub microsites compared to the others. Shrub microsites with small mammal burrows had significantly more N and P than those without burrows. Non-vegetated microsites in washes and plant interspaces contained very low N and P levels. Mg, Na, pH and cation exchange capacity were highest in soils under Lycium shrubs, while Ca levels were highest in wash soils. Arbuscular mycorrhizal spore densities were generally low (0–0·2 spores g −1 soil) except for Lycium soils, which contained 1·8 spores g −1 soil. Wash and interspace soils lacked spores but had mycorrhizal inoculum potential values similar to the other microsites, indicating that mycorrhizal propagules were present. Thus, the presence of perennial shrubs strongly influenced microsite soil characteristics and resulted in higher nutrient levels. Small mammal burrows further enhanced the mineral nutrient content of soils. In addition, all soil characteristics except for spore density differed among the three sites across the bajada, and interactions between microsite and site were common. Clearly, soil resources for plants are spatially heterogeneous in this desert ecosystem and differ greatly between adjacent micro- and macrosites in this L. tridentata–A. dumosa community.

A new genus and species of Aphodiini (Coleoptera: Aphodiidae) inhabiting burrows of small mammals in Lebanon’s mountains

Grandinaphodius inferorum n. gen. n. sp. is described from Lebanon (type locality: Faraya, Jounie prov.), found at the entrance to the burrows of small mammals. Data on the ecology and biology are provided, and drawings of epipharynx, labium, male genitalia and dorsal habitus of both male and female are given. Based on the study of its holotype, the new combination Euorodalus elephantinus (Petrovitz, 1967) is proposed.

Post-breeding migrations of newts (Triturus cristatus and T. marmoratus) with contrasting ecological requirements

Two newt species with contrasting ecological requirements (Triturus cristatus and T. marmoratus) were radio-tracked after leaving a shared breeding pond in western France. Movements of 30 individuals were recorded over 491 days. During the first terrestrial night, the newts migrated with high directionality up to 137 m to their refuges. Burrows of small mammals were among the favourite refuges. Movements after the first night were mostly underground and over shorter distances (< 6.8 m). Sixty-four per cent of all tracked newts stayed within 20 m of the pond edge, and migrations were recorded up to 146 m away from the pond. Both species preferred areas with bushes, hedgerows and trees, and avoided pastures and open areas. Migration in the direction of a habitat type characterized by trees and underground shelters was favoured over migrations in other directions. A clear terrestrial niche separation between the two newt species was not observed. The results are discussed in relation to previous findings that T. cristatus supersedes T. marmoratus as a consequence of anthropogenic change to the terrestrial environment, affecting the species differentially.

Post‐breeding migrations of newts (Triturus cristatus and T. marmoratus) with contrasting ecological requirements

AbstractTwo newt species with contrasting ecological requirements (Triturus cristatus and T. marmoratus) were radio‐tracked after leaving a shared breeding pond in western France. Movements of 30 individuals were recorded over 491 days. During the first terrestrial night, the newts migrated with high directionality up to 137 m to their refuges. Burrows of small mammals were among the favourite refuges. Movements after the first night were mostly underground and over shorter distances (&lt; 6.8 m). Sixty‐four per cent of all tracked newts stayed within 20 m of the pond edge, and migrations were recorded up to 146 m away from the pond. Both species preferred areas with bushes, hedgerows and trees, and avoided pastures and open areas. Migration in the direction of a habitat type characterized by trees and underground shelters was favoured over migrations in other directions. A clear terrestrial niche separation between the two newt species was not observed. The results are discussed in relation to previous findings that T. cristatus supersedes T. marmoratus as a consequence of anthropogenic change to the terrestrial environment, affecting the species differentially.

Introduction to the Special Issue: ecological significance of open burrow systems

Krotovinas, burrows of small mammals, occur widely in the soils of the steppes. The distribution and effect of krotovinas on soil organic carbon (SOC) stocks were studied in a deep profile (450 cm) at an archaeological site of the Palaeolithic period at Shenyang Agricultural University of China. It was found krotovinas occurred at all depths, and there was variation in their distribution and size. The density of krotovinas increased with depth, and was the highest (10/m2) at 250 cm depth. The average area of krotovinas' sections in most part of the profile ranged from 100 to 160 cm2. Krotovinas covered an area of 7 to 17% of the profile wall. Average SOC concentration in the krotovinas was 5.3 g/kg, whereas it was 4.5 g/kg in the surrounding soil matrix. SOC stocks at 100 to 450 cm accounted for 72% of total SOC stocks at 0 to 450 cm depth. Total SOC stock in the whole profile (0 to 450 cm) was 295 t/ha considering the presence of krotovinas, whereas it was 274 t/ha when the krotovinas were excluded. This study shows how krotovinas can be quantified, and that krotovinas can affect SOC concentration and change patterns of SOC distribution. The amount of SOC stored in deep soils should be taken into consideration for evaluating SOC stocks.

Effects of small mammal burrows on water infiltration in a cool desert environment.

The hypothesis that small mammal burrows can increase the amount of water infiltrating into the soil profile was tested. The amount of water added to the soil profile from spring recharge in areas adjacent to ground squirrel (Spermophilus townsendii and S. elegans) burrows was compared to nearby areas without burrows. Recharge amounts in burrow areas were significantly higher than nonburrow areas. An average of 21% more of the winter precipitation infiltrated into the soil near burrows. The amount of recharge was also found to be positively related to burrow density. Burrows also affected the distribution of the recharge by adding significantly more water to the deeper portions (>50 cm) of the soil profile.

INFLUENCE OF SMALL MAMMALS ON STORMFLOW RESPONSES OF PINE‐COVERED CATCHMENTS1

ABSTRACT: The relative abundance of small mammals in five forest land cover types on the upper Coastal Plain of north Mississippi was determined. Burrowing mammals accounted for one‐half of the total captures; one shrew species that accounted for over one‐fourth of the total captures had a strong affinity for well‐stocked pine plantations. The opportunity for detention and retention of rainfall was enhanced by burrowing activity. Reductions of stormflow volumes 12 to 15 years after replacing poor quality, upland hardwoods with loblolly pine were only partially explained by increased interception of rainfall; much of the residual reductions are postulated to be due to small mammal burrows. Small mammal activity deserves further study as an important aspect of forest land hydrology.

Use of doubly-labeled water ((3)HH (18)O) for determination of H 2O flux and CO 2 production by a mammal in a humid environment.

The accuracy of the doubly labeled water ((3)HH(18)O) technique for estimating H2O flux and CO2 production in pocket gophers was evaluated in laboratory experiments. Experiments were conducted under conditions of elevated humidity in order to determine the influence of unlabeled H2O vapor input on H2O flux and CO2 production rates which are determined from isotope turnover. High humidity is commonplace in burrows of many small mammals, including those of the pocket gopher, and theoretically could introduce substantial errors when determining these rates with isotopic procedures.Water influx that was estimated from tritium turnover was not significantly different from actual H2O influx which was determined from feeding rates. Also, (3)HH(18)O techniques yielded estimates of CO2 production that were not significantly different from values determined from energy intake rates. Such close agreement was not anticipated. The unexpected accuracy probably results due to offsetting errors associated with (1) the influx of unlabeled H2O vapor through the skin and lungs of labeled pocket gophers and (2) the effects of biological fractionation of isotopes in the body H2O of labeled pocket gophers.

Burrowing ability and behavior of salamanders of the genus Ambystoma

The burrowing ability and behavior of five species of fossorial salamanders of the genus Ambystoma were examined in the laboratory. Individual salamanders were subjected to three experimental treatments to test the hypothesis that salamanders do not actively dig their own burrows but alternatively enlarge cracks, crevices, and invertebrate or small mammal burrows for occupancy. One species, A. tigrinum, actively dug burrows under all experimental treatments while A. talpoideum actively dug 50% of the time. The other species (A. opacum, A. annulatum, A. maculatum) burrowed passively by using their snout and body to enlarge holes or cracks provided. Individual salamanders not able to burrow (actively or passively) underground incurred significant water loss (25–39%) and several died after a 24-h test period. Digging ability was not clearly related to snout–vent length, head width, or forelimb diameter. These data suggest that the digging ability of ambystomatid salamanders may be a behavioral adaptation and is not simply related to morphology.

Wormlike Objects (Nematode Larvae?) on Two Gamasine Mites Taken from Noctuid Moths

Although phoresy upon insects by larval nematodes is well known (Goodey 1951), their occurrence on mites has seldom been reported. Davydova et al. (1967) found numerous examples on gamasines from the burrows of small mammals and the nests of birds in West Siberia. While they could not determine the species of larval worms, they considered that such phoresy favors the distribution and the completion of the life cycle in forms parasitic upon the vertebrates in the nests or burrows of which the mites were found. Dr. E. W. Baker (personal communication) recalls seeing 1 mite bearing a supposed nematode larva, and remembers the report of a similar finding in a Russian paper published prior to 1954, but could give no further details. I have not located the early Russian report, nor have I made an exhaustive search of the literature for other instances.