Digging Activities Research Articles

Effect of noise on sand digging and emergence activities in green turtle (Chelonia mydas) hatchlings

Anthropogenic noise affects animal behavior and physiology. However, relatively few studies have been conducted on the effects of noise on beach-associated animals. This study evaluated the effects of noise on sound emission, sand digging activity, and emergence from the sand surface by green turtle (Chelonia mydas) hatchlings. Acoustic recorders and infrared cameras were used to investigate the behavior of hatchlings in sand-filled chambers under three acoustic conditions: 1) a control treatment, which was silent throughout the experiment; 2) an environmental noise treatment, which exposed the hatchlings to white noise (WN) at a sound pressure level (SPL) approximately 13 dB higher than that of the control, which is similar to that of a natural beach; and 3) a loud noise treatment, which exposed them to WN at an SPL approximately 25 dB higher than that of the control. The WN ranged from 0 to 4 kHz with a repeating cycle of 30 min sound emission and 2 h 30 min silence. Sound emissions from green turtle hatchlings were detected; however, the amount of sound emissions was too small to discuss their ecological significance. The time to emergence and total number of digging bouts in the 24 h pre-emergence periods were not significantly different among treatments; however, the number of digging bouts was significantly higher during loud noise exposure. The response to loud noises may play a role in allowing hatchlings to escape from threats and/or coordinate synchronous behavior among multiple individuals. However, because the number of digging bouts decreased after loud noise exposure, prolonged exposure to loud noise may have detrimental effects on hatchlings, such as depletion of the energy reserves available to the hatchlings. Thus, anthropogenic noise on or around beaches and it effect on animals should be carefully considered.

Burrow builders as ecosystem engineers for pit-building antlions (Neuroptera: Myrmeleontidae).

Burrow builders are often classified as ecosystem engineers because their digging activities regulate the availability of resources for other organisms. As antlion larvae prefer to construct their traps in bare sandy or loose soil, they could benefit from burrowing activities. We investigated the role of burrow builders as ecosystem engineers for antlions (Myrmeleontidae) in a tropical semideciduous forest in Mexico. The number of traps of antlion larvae was recorded on 30 sampling quadrats (45cm) at the entrance of burrows (of unidentified builders) and on 30 paired off-burrow quadrats. Additionally, the percentage of bare soil was estimated for the 60 quadrats sampled. Of the 30 quadrats at the entrance of burrows, a total of 336 traps were recorded, with 21 (70%) of them having at least one trap, while for the 30 off-burrows quadrats, only two (6.6%) of them had traps, just three in total. The percentage of bare soil and the abundance of traps were significantly greater in quadrats at the entrance of burrows compared to quadrats without burrows. The abundance of traps at the entrance of burrows was positively affected by the percentage of bare soil. The few traps in the off-burrows quadrats suggested that, in addition to the limited bare soil, ground compactness probably limits the establishment of antlion larvae. Otherwise, when digging, burrow builders create small patches of bare sandy soils that are used by these insects. We concluded that the ecosystem engineering effect of burrow builders is an important structuring element for antlion populations in the tropical semideciduous forest studied.

Toxicity, horizontal transfer, and physiological and behavioral effects of cycloxaprid against Solenopsis invicta (Hymenoptera: Formicidae).

The red imported fire ant, Solenopsis invicta Buren, is a significant urban, agricultural, and medical pest with a wide distribution in the world. Surface or mound treatment using contact insecticide is one of the main methods to control S. invicta. In the present study, cycloxaprid, a newly discovered neonicotinoid insecticide, was evaluated for S. invicta control and compared with two referent insecticides, imidacloprid and bifenthrin. Surfaces or sand treated with cycloxaprid, imidacloprid, or bifenthrin caused high mortality of S. invicta workers, and the action of cycloxaprid or imidacloprid was slower than bifenthrin. Like imidacloprid and bifenthrin, cycloxaprid can be horizontally transferred from corpses or live donor ants to recipient ants. In addition, cycloxaprid- or imidacloprid-treated surfaces significantly induced the activities of acetylcholinesterase (AChE) and detoxification enzymes; nevertheless, they had no significant effect on the foraging behaviors of S. invicta workers. Also, sand treated with cycloxaprid or imidacloprid did not negatively affect the digging activities of ants. Interestingly, S. invicta workers excavated significantly more sand containing 0.01 mg/kg cycloxaprid than untreated sand in the no-choice digging bioassays. In addition, extensive nesting activities (sand excavation and stacking) were observed in the flowerpots containing untreated sand or sand treated with cycloxaprid or imidacloprid. On the contrary, bifenthrin significantly reduced the foraging, digging, and nesting activities of S. invicta workers. Cycloxaprid is a slow-acting and nonrepellent insecticide against S. invicta workers, and its contact and horizontal toxicities are slightly higher than imidacloprid. © 2022 Society of Chemical Industry.

Translocations of digging mammals and their potential for ecosystem restoration: a review of goals and monitoring programmes

Abstract Globally, translocations are commonly used to improve the conservation status of threatened species. There is increasing recognition that translocations of ecosystem engineers also have the potential to restore ecological processes. Digging mammals are often considered to be ecosystem engineers, as their diggings provide shelter for other species and can significantly alter soil properties, with subsequent changes to vegetation. Using Australian species as a case study, we reviewed published and grey literature on digging mammal translocations to determine how often these translocations are conducted to restore ecosystem processes. We documented ecosystem‐level monitoring and research efforts, and assessed whether restoration was perceived to be occurring post‐release. At least 208 translocations of 24 digging mammal species have been conducted in Australia, with a further 38 planned for the near future. Prior to 2019, only 3% of translocations included a goal relating to the restoration of ecosystem processes associated with digging activities. Nearly a quarter of pre‐2019 translocations have been the subject of some form of ecosystem‐level monitoring or research, but long‐term ecosystem‐level monitoring was very rare. In contrast, 74% of the translocations planned for post‐2018 include a goal relating to the restoration of ecological processes and most also include plans to conduct ecosystem‐level monitoring. Ecosystem restoration was perceived to be occurring for 26% of the pre‐2019 translocations. None of the documents we reviewed indicated that ecological degradation had occurred post‐translocation, even when declines in other taxa were recorded. The restoration of ecosystem processes is increasingly being identified as a goal for translocation programmes. Where this is the case, we suggest that translocation practitioners include success criteria for the restoration of ecosystem processes, and commit to long‐term monitoring designed to detect ecosystem‐level effects of translocations.

Optimalisasi dan Produktivitas Alat Gali-Muat dan Alat Angkut pada Tambang Batu Granit PT Vitrama Properti di Desa Air Mesu, Kecamatan Pangkalan Baru, Kabupaten Bangka Tengah

Granite mining activity of PT Vitrama Properti is done by blasting system followed by work combination of one unit Excavator serve four units Dump Truck with a production target of 60.000 tonnes/month. The method of this research is quantitative descriptive to know achieving optimization and productivity Excavator-Dump Truck and efforts are needed to achieve the production target. The results of this research that digging and transport activities not run optimally seen from the low efficiency of work, which only reached 46,57% for digging activity and 40,51% material transport activities of the actual productivity of 29503,44 tons / month for Exacavator and 20754,72 tons / month for Dump Truck. Efforts are needed to achieve the production target is to make improvements circulation time of Dump Truck, increase the work efficiency of digging-transport activity and adding charging frequency to vessel Dump Truck.

Woody Species Diversity and Management in Homegarden Agroforestry: The Case of Shashemene District, Ethiopia

The study was conducted in Shashemene district, Ethiopia. Management-related data were collected using informal and formal surveys. Woody species diversity and related parameters were collected from 60 households. Woody species with ≥5 cm diameter at breast height (DBH) were measured and recorded and below 5 cm were counted and recorded in 10 m ∗ 10 m and 1 m ∗ 1 m plot, respectively. A total of 36 woody species were recorded, of which 58% were indigenous to the area. The overall mean number of woody species per plot was 3.13. Four woody species, namely, Cordia africana, Croton macrostachyus, Persea americana, and Catha edulis, showed highest importance value index. Farmers’ preference ranks for selected woody species were recorded in order of Cordia africana, Eucalyptus camaldulensis, Croton macrostachyus, and Cupressus lusitanica, respectively. The similarity in woody species composition between the study villages ranged from 0.46 to 0.60. To sustain the management of woody species, farmers implemented pruning, thinning, composting, weeding, digging, and watering activities in the area. Garden availability and market and road accessibility are the major determinants of woody species in homegarden agroforestry. The study revealed woody species diversity, management practices implemented, and factors affecting woody species diversity management in homegarden agroforestry. Therefore, government should be worked on infrastructure, resource reallocation, and awareness creation in communities for the better improvement of species diversity and its sustainable management in homegarden agroforestry.

Spider (Araneae) and harvestman (Opiliones) communities are structured by the ecosystem engineering of burrowing mammals

Abstract Burrowing mammals through their digging activities are important ecosystem engineers and bioturbators in grassland ecosystems. Through habitat formation, they can have significant effects on other species in an ecosystem, structuring their abundance and diversity. We analysed the effect of the European ground squirrel (Spermophilus citellus) on spider (Araneae) and harvestman (Opiliones) communities, because these arachnids are the most abundant and dominant predators with a great variety of foraging strategies, and their community composition is strongly influenced by the physical structure of the environment. We established replicate mound plots positioned directly in the centre of ground squirrel mounds with paired off‐mound control plots undisturbed by ground squirrels. We sampled spiders and harvestmen using pitfall traps on 30 ground squirrel mounds and 30 paired off‐mound control plots at two study sites differing in grazing intensity and plant species richness. We found that the response of spiders was site‐specific, while harvestmen responded consistently to disturbances by burrowing mammals. Mounds exhibited increased abundance and species richness of harvestmen at both study sites, while species richness of spiders was increased only in intensively managed grassland. We also detected compositional changes of the arachnid community on the mounds in comparison to the grassland matrix. Our findings indicate that burrowing mammals through physical state changes in abiotic and biotic material modulate the resources for other species and maintain a high diversity of biotic communities in intensively grazed grasslands.

Breeding populations of a declining farmland bird are dependent on a burrowing, herbivorous ecosystem engineer

In recent decades, numerous farmland birds have experienced considerable population declines. The loss of nutrient-poor habitats with short vegetation due to land-use intensification, abandonment or nitrogen deposition helps account for this decrease. Soil-disturbing ecosystem engineers can naturally create short and sparsely vegetated swards with beneficial effects for biodiversity.The aim of this study is to examine the influence of the European rabbit (Oryctolagus cuniculus) as an ecosystem engineer on breeding populations of the severely declining northern wheatear (Oenanthe oenanthe) on the East Frisian Islands (Lower Saxony, northern Germany). Rabbits were found to have had a considerable influence on the structure of the dune grassland, the main breeding habitat of the wheatear: high rabbit abundance resulted in greater burrow density and more bare ground. Wheatears were also more abundant on islands with larger rabbit populations. At the plot level, wheatear abundance increased with burrow density and the cover of potential foraging habitats (short vegetation). In addition, the likelihood of nest-building increased with burrow density and decreased with vegetation height.We thoroughly investigated the dependence of the northern wheatear on large populations of the ecosystem engineer European rabbit. Through their digging and grazing activities, rabbits create two key resources for breeding wheatears: (i) sufficient burrows as potential nesting sites and (ii) the availability of short vegetation as foraging habitats.

Goliath frogs build nests for spawning – the reason for their gigantism?

ABSTRACTIn contrast to its popularity, astonishingly few facts have become known about the biology of the Goliath Frog, Conraua goliath. We herein report the so far unknown construction of nests as spawning sites by this species. On the Mpoula River, Littoral District, West Cameroon we identified 19 nests along a 400 m section. Nests could be classified into three types. Type 1 constitutes rock pools that were cleared by the frogs from detritus and leaf-litter; type 2 constitutes existing washouts at the riverbanks that were cleared from leaf-litter and/or expanded, and type 3 were depressions dug by the frogs into gravel riverbanks. The cleaning and digging activities of the frogs included removal of small to larger items, ranging from sand and leaves to larger stones. In all nest types eggs and tadpoles of C. goliath were detected. All nest types were used for egg deposition several times, and could comprise up to three distinct cohorts of tadpoles. Nests seemed to be clustered. Camera trapping revealed that nests are guarded by adult frogs at night. The breeding nests may allow the frogs to deposit their eggs away from the torrent rivers, and potential egg and tadpole predators. As nest construction, at least in some cases, requires the removal of large and heavy items, we hypothesize that this can only be achieved by decent sized frogs, possibly explaining the unique size of the species.

Functional morphology and paleoecology of Pilosa (Xenarthra, Mammalia) based on a two-dimensional geometric Morphometrics study of the Humerus.

The relationship between humerus shape and the modes of exploring substrate among extinct and extant Pilosa (especially anteaters and ground sloths) were investigated here. We used geometric morphometrics and discriminant analyses to relate morphological patterns and their possible ecological categories. Our results suggest that plesiomorphic taxa such as Nothrotheriidae, most Megalonychidae and basal Megatheriidae tend to have more slender humerus, associated to generalist habitus (climbing, swimming and digging activities), and while Mylodontidae developed specialized digging habitus. Additionally, we inferred ground sloths which inhabited the Brazilian territory during the Quaternary likely occupied at least four different niches. Mammals display morphofunctional adaptations on the limbs which are reflected on their modes of substrate exploration. Herein, we analyzed the humerus morphology of ground sloths and anteaters. Our results suggest that most of the Pleistocene Mylodonts were fossorial taxa, while most of the Santacrucian sloths plus extant anteaters were semiarboreal or semiaquatic taxa. The Pleistocene Megatheriidae should be ambulatory.

Introducing a Regulatory Policy Framework of Bait Fishing in European Coastal Lagoons: The Case of Ria de Aveiro in Portugal

The harvesting of bait through digging in coastal mudflats is practiced for recreational and commercial purposes in European coastal systems including the Ria de Aveiro coastal lagoon on the northwest Atlantic coast of Portugal. The scale of harvesting in the Ria de Aveiro has recently increased due to the current economic climate in Portugal, with targeting of the polychaete, Diopatra neapolitana species or “casulo” as it is widely known in the Aveiro region. The national authorities have attempted to control casulo digging by issuing a regulation (Ordinance) in 2014 on the maximum daily catch limit to be caught by each individual. The daily catch limit is intended to represent the Maximum Sustainable Yield (MSY) for casulo beyond which overfishing will occur. The monitoring of the regulatory measures is expected to be conducted through on-site inspections in the digging areas. However, weak law enforcement was noticed, while there is also controversy over the daily catch limit (quota) stipulated by the Ordinance. To this end, the current study attempted to assess digging activities through remote monitoring and random inspections for a better policy enforcement of the national regulation. In addition, different harvesting scenarios were employed through a simplified bioeconomic model to attribute the current and future harvesting trends of bait digging in Aveiro coastal lagoon. The study findings indicate that remote monitoring coupled with some onsite interviews could be a more effective approach for the implementation of the current bait digging policy. Further, the results point to a distinctive discrepancy between the daily catch amount (MSY) introduced by the national legislation and the study findings which should be further scrutinized. The diggers seem to have reached the sustainable harvest identified by the present research. The current economic hardship in Portugal and the low profitability in similar employment sectors will possibly attract more diggers and increase harvesting in the near future. An increased harvest would likely trigger overfishing of D. neapolitana with unknown consequences for the population of the species as well as the aquatic ecosystem. The socio-economic and environmental effects are yet to be further clarified with more detailed data and advanced modeling techniques to ensure the sustainability of the activity.

An unusual tumulus or cenotaph at Cozzo Rotondo, town of Grifone (Bisignano, Cosenza, Italy). New and old geological investigation for an archaeological discovery

The hillock named “Cozzo Rotondo”, in Grifone (Bisignano, province of Cosenza, Italy), has attracted the attention of numerous researchers since 1986, when it was discovered, and – owing to its peculiar morphology – is described as a monumental tumulus. This research, integrating old unpublished data and new ones, aims to define its internal structure and how it was made. In fact , its shape is in striking contrast with the geomorphological context of the surrounding area. Its shape, orientation and spatial setting recall many tumuli of Central Europe. A series of popular myths and legends, as well as its curious name, are associated with this hillock, conferring it a certain halo of mystery. The geological, geophysical and geomorphological investigations carried out in the past – in particular those quoted in this study – confirm that this hillock is made up of homogeneous sand arranged in natural layers and that its shape is the result of the digging and remodelling of a natural slope. Based on geomorphological observations, it has been estimated that the volume of earth dug out is about 8,000 m3, concentrated nearly exclusively in the southwestern sector of the hillock, where the soils are more recent and thinner. Subsequently, the material was scattered in the underlying plain, thus forming a gentle bluff, some 1-2 m thick, over an area of 4,000 m2, as confirmed by georadar surveying. In particular, geological investigations carried out on a series of excavations have clearly shown the presence of a moat surrounding an ancient building and a clayey colluvium, which were dated to the 8th century CE (by means of 14C dating) and after the 8th century BCE (by means of fluorescence analyses), respectively. It was therefore suggested that the digging and remodelling activities took place in this time interval. Geoelectrical and georadar surveying seems to show the absence of voluminous finds, strengthening the hypothesis – expressed also by many archaeologists – that the hillock of Cozzo Rotondo is a quaint tumulus resulting from accurate partial modelling, almost totally made by a sort of “deep carving”. More likely, it is a monumental cenotaph, built in a very original way.

Scratching beneath the surface: Bandicoot bioturbation contributes to ecosystem processes

AbstractAnimals that forage for food or dig burrows by biopedturbation can alter the biotic and abiotic characteristics of their habitat. The digging activities of such ecosystem engineers, although small at a local scale, may be important for broader scale landscape processes by influencing soil and litter properties, trapping organic matter and seeds, and subsequently altering seedling recruitment. We examined environmental characteristics (soil moisture content, hydrophobicity and litter composition) of foraging pits created by the southern brown bandicoot (Isoodon obesulus; Peramelidae), a digging Australian marsupial, over a 6‐month period. Fresh diggings typically contained a higher moisture content and lower hydrophobicity than undisturbed soil. A month later, foraging pits contained greater amounts of fine litter and lower amounts of coarse litter than adjacent undug surfaces, indicating that foraging pits may provide a conducive microhabitat for litter decomposition, potentially reducing litter loads and enhancing nutrient decomposition. We tested whether diggings might affect seedling recruitment (seed removal by seed harvesters and seed germination rates) by artificially mimicking diggings. Although there were no differences in the removal of seeds, seedling recruitment for three native plant species (Acacia saligna, Kennedia prostrata and Eucalyptus gomphocephala) was higher in plots containing artificial diggings compared with undug sites. The digging actions of bandicoots influenced soil moisture and hydrophobicity, the size distribution of litter and seedling recruitment at a local scale. The majority of Australian digging mammals are threatened, with many suffering substantial population and range contraction. However, their persistence in landscapes plays an important role in maintaining the health and function of ecosystems.

Fine-scale spatial distribution of the common lugworm Arenicola marina, and effects of intertidal clam fishing

Despite its ubiquity and its role as an ecosystem engineer on temperate intertidal mudflats, little is known of the spatial ecology of the lugworm Arenicola marina. We estimated lugworm densities and analyzed the spatial distribution of A. marina on a French Atlantic mudflat subjected to long-term clam digging activities, and compared these to a nearby pristine reference mudflat, using a combination of geostatistical techniques: point-pattern analysis, autocorrelation, and wavelet analysis. Lugworm densities were an order of magnitude greater at the reference site. Although A. marina showed an aggregative spatial distribution at both sites, the characteristics and intensity of aggregation differed markedly between sites. The reference site showed an inhibition process (regular distribution) at distances <7.5 cm, whereas the impacted site showed a random distribution at this scale. At distances from 15 cm to several tens of meters, the spatial distribution of A. marina was clearly aggregated at both sites; however, the autocorrelation strength was much weaker at the impacted site. In addition, the non-impacted site presented multi-scale spatial distribution, which was not evident at the impacted site. The differences observed between the spatial distributions of the fishing-impacted vs. the non-impacted site reflect similar findings for other components of these two mudflat ecosystems, suggesting common community-level responses to prolonged mechanical perturbation: a decrease in naturally-occurring aggregation. This change may have consequences for basic biological characteristics such as reproduction, recruitment, growth, and feeding.

Analysis of the causes of spawning of large-scale, severe malarial epidemics and their rapid total extinction in western Provence, historically a highly endemic region of France (1745-1850).

BackgroundThe two main puzzles of this study are the onset and then sudden stopping of severe epidemics in western Provence (a highly malaria-endemic region of Mediterranean France) without any deliberate counter-measures and in the absence of significant population flux.MethodsMalaria epidemics during the period from 1745 to 1850 were analysed against temperature and rainfall records and several other potentially relevant factors.ResultsStatistical analyses indicated that relatively high temperatures in early spring and in September/October, rainfall during the previous winter (principally December) and even from November to September and epidemics during the previous year could have played a decisive role in the emergence of these epidemics. Moreover, the epidemics were most likely not driven by other parameters (e.g., social, cultural, agricultural and geographical). Until 1776, very severe malarial epidemics affected large areas, whereas after this date, they were rarer and generally milder for local people and were due to canal digging activities. In the latter period, decreased rainfall in December, and more extreme and variable temperatures were observed. It is known that rainfall anomalies and temperature fluctuations may be detrimental to vector and parasite development.ConclusionThis study showed the particular characteristics of malaria in historical Provence. Contrary to the situation in most other Mediterranean areas, Plasmodium falciparum was most likely not involved (during the years with epidemics, the mean temperature during the months of July and August, among other factors, did not play a role) and the population had no protective mutation. The main parasite species was Plasmodium vivax, which was responsible for very severe diseases, but contrary to in northern Europe, it is likely that transmission occurred only during the period where outdoor sporogony was possible, and P. vivax sporogony was always feasible, even during colder summers. Possible key elements in the understanding of the course of malaria epidemics include changes in the virulence of P. vivax strains, the refractoriness of anophelines and/or the degree or efficiency of acquired immunity. This study could open new lines of investigation into the comprehension of the conditions of disappearance/emergence of severe malaria epidemics in highly endemic areas.

CD4⁺ but not CD8⁺ T cells revert the impaired emotional behavior of immunocompromised RAG-1-deficient mice.

An imbalanced immune system has long been known to influence a variety of mood disorders including anxiety, obsessive-compulsive disorders and depression. In this study, we sought to model the impact of an immunocompromised state on these emotional behaviors using RAG-1−/− mice, which lack T and B cells. We also investigated the relative contribution of CD4+ or CD8+ T cells to these manifestations using RAG-1−/−/OT-II and RAG-1−/−/OT-I transgenic mice, respectively. Our results show that RAG-1−/− mice present a significant increase in digging and marble-burying activities compared with wild-type mice. Surprisingly, these anxiety-like behaviors were significantly reverted in RAG-1−/−/OT-II but not RAG-1−/−/OT-I transgenic mice. Immunodepletion experiments with anti-CD4 or anti-CD8 in C57/BL6 mice or repopulation studies in RAG-1−/− mice did not reproduce these findings. Microarray analysis of the brain of RAG-1−/− and RAG-1−/−/OT-II mice revealed a significantly different gene fingerprint, with the latter being more similar to wild-type mice than the former. Further analysis revealed nine main signaling pathways as being significantly modulated in RAG-1−/− compared with wild-type mice. Taken together, these results suggest that life-long rather than transient immunodeficient conditions influence the emotional behaviors in mice. Most interestingly, these effects seem to correlate with a specific absence of CD4+ rather than CD8+ T cells. Validation of these findings in man might provide new clues on the mechanism by which early life immune modulation might impact mood response in adults and provide a further link between immune and emotional well-being.

Long-term Decline of a Fringing Coral Reef in the Northern South China Sea

The Luhuitou coral reef is a fringing reef at Hainan Island in the northern South China Sea. Since the 1960s, the reef has experienced several significant ecological changes. During that interval, the mean coral cover decreased dramatically from 80-90% in 1962-65 and to just 12% in 2009. In the 1960s, the coral community structure was divided into three well-defined zones: a Goniastrea zone and Montipora zone (both on the reef flat) and an Acropora zone (on the reef slope). However, by 2009, Porites lutea became the dominant species on the reef flat, whereas the predominance of Acropora on the reef slope weakened significantly. There are few long-established Porites lutea colonies present, with approximately 80% being younger than 30 years old. This demographic pattern differs significantly from healthy coral reefs, which are typically dominated by large, well-established (and mature) coral colonies. The long-term decline of the Luhuitou coral reef has most likely been driven as a result of anthropogenic activities, such as overfishing, destructive fishing, reef rock digging, and mariculture and tourism activities. Our study reinforces previous works and highlights the vulnerability of coral reefs to anthropogenic impacts.

Foraging activity by the southern brown bandicoot (Isoodon obesulus) as a mechanism for soil turnover

Mammals that forage for food by biopedturbation can alter the biotic and abiotic characteristics of their habitat, influencing ecosystem structure and function. Bandicoots, bilbies, bettongs and potoroos are the primary digging marsupials in Australia, although most of these species have declined throughout their range. This study used a snapshot approach to estimate the soil turnover capacity of the southern brown bandicoot (Isoodon obesulus, Shaw 1797), a persisting digging Australian marsupial, at Yalgorup National Park, Western Australia. The number of southern brown bandicoots was estimated using mark–recapture techniques. To provide an index of digging activity per animal, we quantified the number of new foraging pits and bandicoot nose pokes across 18 plots within the same area. The amount of soil displaced and physical structure of foraging pits were examined from moulds of 47 fresh foraging pits. We estimated that an individual southern brown bandicoot could create ~45 foraging pits per day, displacing ~10.74 kg of soil, which extrapolates to ~3.9 tonnes of soil each year. The digging activities of the southern brown bandicoots are likely to be a critical component of soil ecosystem processes.

Joint morphology and its relation to function in elite sprinters

Joint structure seems well suited to the functional needs of the various animals who excel at running, digging, swimming, and other activities, but there is little evidence to suggest that variation in joint structure among humans determines function. We present experimental measurements made in human sprinters and non-sprinters, including measurements of tendon excursion from ultrasound imaging and bone geometry from magnetic resonance imaging, that suggest differences in ankle joint anatomy between these two groups. The functional significance of these morphological differences is explored using non-periodic forward dynamic simulation of a sprinter's initial acceleration.

Post-weaning ontogeny of the mandible in fossorial water voles: ecological and evolutionary implications

Ventura, J. and Casado-Cruz, M. 2011. Post-weaning ontogeny of the mandible in fossorial water voles: ecological and evolutionary implications. —Acta Zoologica (Stockholm) 92: 12–20. Geometric morphometrics was applied to the mandible of fossorial water voles (Arvicola terrestris monticola) to determine size and shape variations in this structure during post-weaning ontogeny. The sample consisted of collection specimens obtained in the Aran Valley (Spain), which were grouped into six age classes. Mandible size and shape did not differ significantly between sexes, but between age classes. Mandible size accounted significantly for the shape variation. After the size-related differences were removed, the mandible shape did not show significant sexual dimorphism but differences by age remained significant. The main shape changes occur between the third and tenth weeks of life and are related to the shift from suckling to a herbivorous diet. Although mandible shape was less remodelled after that age, an appreciable variation also occurs during adulthood. Age-related changes lead to enhancing the digging potential of the mandible, which in adults becomes a robust structure with an increased surface and stronger crests for muscle insertion. As part of the mandible shape variation was not related to the size-dependent adjustment and diet does not vary significantly between juvenile and adult voles, shape changes that occur during adulthood can be related to the mechanical stress derived from digging activities.