Introduction Of Cattle Research Articles

Evaluation of the spatial and temporal distribution of and risk factors for Bluetongue serotype 1 epidemics in sheep Extremadura (Spain), 2007–2011

Extremadura has been one of the regions in Spain most severely affected by Bluetongue (BT) epidemics. The first incursion of BTV, which was successfully eradicated one year later, occurred in 2004, involving the BTV-serotype 4. However, a second incursion occurred in September 2007, this time involving serotype 1. Since then, the implementation of intensive vaccination programs have significantly reduced BTV-1 occurrence, but the disease has not been completely eradicated yet.This study aimed to provide, for the first time, a complete description of the spatial and temporal patterns of BTV-1 occurrence in sheep in Extremadura from 2007 to 2011 and to identify the risk factors that contributed to the seasonal occurrence of BTV-1 in this region. The results showed that risk factors contributing to BTV-1 occurrence in sheep changed between 2007 and 2011. Initially, when the population was still immunologically naïve, the main risk factors for BTV-1 occurrence were extensive management practices, large sheep farms and Culicoides abundance on farms. However, after the implementation of vaccination, other factors became more relevant for BTV-1 occurrence, mostly related to BTV reservoirs, such as the proximity of cattle farms or the introduction of cattle into farms. The Talaverana sheep breed also seemed to be associated with a significantly higher risk of BTV-1 occurrence, although it may be due to confounding factors, such as the geographical concentration of where this breed is kept and/or management practises used for this breed. The results of this study suggest that preventive and control strategies, including vaccination and active surveillance strategies, should be primarily focused on cattle farms kept in close vicinity to sheep flocks as well as in high-risk sheep farms (i.e. farms with a large farm size keeping both cattle and sheep and with a high number of animal introductions). Methods and results presented here may be used to guide decisions for the annual update of the control and eradication program in Spain.

Grazing Intensity Influences Ground Squirrel and American Badger Habitat Use in Mixed-Grass Prairies

Ground squirrel (Spermophilus spp.) and American badger (Taxidea taxus) burrowing activities are ecologically important disturbances that contribute to the heterogeneity of prairie environments. These activities also have a strong impact on habitat suitability for many other grassland species. However, effects of cattle grazing intensity on ground squirrel and American badger burrows are not well understood. From 2006 to 2012 we evaluated effects of grazing intensity and vegetation type on American badger burrow occurrence and ground squirrel burrow abundance using a manipulative grazing experiment in Grasslands National Park of Canada, Saskatchewan. The study area consisted of nine 300-ha pastures at a range of stocking rates, from very low to very high for the region. Each pasture had 10 plots (six upland and four lowland) where vegetation and burrow surveys were completed. Burrow abundance and occurrence as well as vegetation structure were assessed for 2 yr prior to the introduction of cattle to this landscape in 2008, which followed at least 15 yr without livestock, and from 2009 to 2012, following introduction of livestock. Data were analyzed using generalized linear mixed models. In upland habitats, ground squirrel burrow counts increased with increasing grazing intensity and decreasing vegetation biomass; conversely, badger burrow occurrence increased with decreased stocking rates and increasing average litter cover and vegetation biomass. Abundance and occurrence of both ground squirrel and badger burrows in lowland habitats was relatively independent of grazing intensity or vegetation. Vegetation composition had little impact on ground squirrel or badger burrows. A range of grazing intensities may contribute to maintaining diversity of burrowing mammals in prairie environments.

Survey of veterinarians in 6 US states regarding their experience with nursing beef calf respiratory disease

Bovine respiratory disease (BRD) is the leading cause of death of nursing beef calves 3 weeks of age and older, but little is known regarding risk factors for calf BRD. The objective of this survey was to describe observations and practices relevant to calf BRD by veterinarians in cow-calf practice. Recipients in Eastern (Georgia, Florida, and West Virginia) and Plains (Iowa, Kansas, and Nebraska) states were asked to complete an on-line questionnaire regarding events occurring between August 2011 and July 2012. A total of 574 veterinarians were solicited to participate; 61 (10.6%) returned responses suitable for inclusion, with an equivalent proportion responding from both regions. Respondents reported that 18% of their cow-calf clients recognized cases of nursing-calf BRD in the previous year, and 14% of their clients had at least 1 calf die of BRD. Infectious agents identified by antemortem or postmortem testing included Mannheimia haemolytica (60% of respondents); Pasteurella multocida (53%); Mycoplasma bovis (37%); bovine respiratory syncytial virus (33%); and bovine viral diarrhea virus (33%). Of responding veterinarians, 80% recommended or administered treatment for an outbreak of nursing-calf BRD in the previous year. Routine administration of respiratory vaccines to nursing beef calves was recommended by 87% of respondents. Respondents identified a variety of risk factors as potentially associated with calf BRD. Two of these, "introduction of cattle from outside sources" and "occurrence of diarrhea in calves", were also significantly associated with nursing-calf BRD in a previous survey of producers in the same states.

Methods of inducing conditioned food aversion to Baccharis coridifolia (mio-mio) in cattle

Three experiments were performed to determine the efficacy of various methods of averting naïve cattle to prevent Baccharis coridifolia poisoning: forced oral administration of 0.5g kg-1 body weight of fresh B. coridifolia; forced inhalation of the smoke from burning B. coridifolia and rubbing the plant on the animals' muzzles and mouths; and introducing the animals into paddocks with low invasion by B. coridifolia. Results demonstrated that cattle forced to ingest low doses become strongly averted if introduced into paddocks 23-26 hours after the aversion. In contrast, cattle introduced into the paddocks between 1-10 hours were not fully averted. Inhalation of B. coridifolia smoke, and rubbing the plant on the animals' muzzles and mouths were not efficient to induce an aversion. The introduction of cattle into paddocks with approximately 1% of B. coridifolia was efficient if the animals remained 5 months in the area, but not if they only remained for 60 hours, as cattle required sufficient time to learn to avoid the plant.

Description and analysis of the cattle trade network in the Madagascar highlands: Potential role in the diffusion of Rift Valley fever virus

In 2008–2009 a Rift Valley Fever (RVF) outbreak occurred in the Anjozorobe area, a temperate and mountainous area of the Madagascar highlands. The results of a serosurvey conducted in 2009 suggested recurrent circulation of RVF virus (RVFV) in this area and potential involvement of the cattle trade in RVFV circulation. The objective of this study was to describe the cattle trade network of the area and analyse the link between network structure and RVFV circulation. Five hundred and sixteen animals that tested negative in 2009 were sampled again in 2010. The 2009–2010 cattle-level seroconversion rate was estimated at 7% (95% CI: 5–10%). Trade data from 386 breeders of 48 villages were collected and analysed using social network analysis methodology, nodes being villages and ties being any movements of cattle connecting villages. The specific practice of cattle barter, known as kapsile, that involves frequent contacts between cattle of two breeders, was observed in addition to usual trade. Trade data were analysed using a logistic model, the occurrence of seroconversion at the village level being the outcome variable and the network centrality measures being the predictors. A negative association was observed between the occurrence of seroconversion in the village and introduction of cattle by trade (p=0.03), as well as the distance to the nearest water point (p=0.002). Conversely, the practice of kapsile, was a seroconversion risk factor (p=0.007). The kapsile practice may be the support for inter-village RVFV circulation whereas the trade network is probably rather implicated in the introduction of RVFV to the area from other parts of Madagascar. The negative association of the distance to the nearest water point suggests that after RVFV introduction, a substantial part of transmission may be due to vectors.

MAKEING A PLAN OF BIOSECURITY ON A CATTLE FARM

On a farm infectious diseases may occur by introducing infected animals, introduction of cattle in the incubation period, carcasses of animals that were not removed properly, vehicles, equipment, clothing and shoes of visitors or employees who have contact with other herds, more often contact with the herd, contact with other animals (horses, dogs, cats, wildlife, rodents, birds, insects), but also by contaminated objects, contaminated food, and improper management of manure when it comes to the creation of dust and scattering (Hristov, 2007). To prevent introduction of infection to the farm or farms in the environment, we use primary and secondary Biosafety measures. The most effective implementation of biosecurity measures on farms provides a development plan for that farm biosecurity. We have developed the biosecurity plan based on detailed observation and analysis of the relevance of indicators and on biosecurity which includes: 1. Making and submitting a written plan for achieving and maintaining biosecurity on farm production based on keeping proper records; 2. Isolation of he farm as a whole or individual segments of manufacturing and production operations; 3. Introduction of newly acquired animals in a herd; 4. Health of the herd; 5. Evaluations of the personnel and the equipment; 6. Traffic and movement control; 7. Attitude towards visitors; 8. Control of food and water; 9. Manure; 10. Disposal of carcasses of dead animals; 11. Relationship to other animals on the farm; 12. Population control of rodents and birds; 13. Sanitation (Stankovic et al,, 2010).

Late Holocene vegetation and fire dynamics from a savanna-forest ecotone in Roraima state, northern Brazilian Amazon

Two sediment cores from Mauritia flexuosa palm swamps have been studied by pollen and charcoal analysis. The cores Fazenda Cigana (FC) and Terra Indígena Aningal (TIA) were taken from a savanna-forest ecotone area in the Roraima State, northern Brazilian Amazon. Based on 5 radiocarbon dates, these records allow the reconstruction of the vegetation fire and climate dynamics during the past 1550 years. At the FC site was recorded a higher proportion of forest cover, suggesting local wetter climatic conditions favorable for forest expansion, especially by gallery forests, between 1550 and 1400 cal yr BP. Stands of M. flexuosa started to establish on the site indicating sufficient soil moisture. From 1400 to 1050 cal yr BP, forest cover retreated while savanna, and the Mauritia palm swamp expanded considerably. The FC site was marked by savanna and Mauritia cover with a slight increase of forest between ca. 1050 and 900 cal yr BP. From 900 to 300 cal yr BP the savanna and palm swamp taxa became dominant and the forest area decreased. At the TIA site the savanna cover was dominant between 1200 and 1000 cal yr BP. From 1000 to 700 forest expanded while savanna and Mauritia palm swamp reduced. Between 700 and 300 cal yr BP savanna and Mauritia palm swamp increased and forest area decreased. The high amount of charred particles found in the sediments, indicate fires with a marked increase between 1400 to 1000 cal yr BP (FC site) and 700 to 300 cal yr BP (TIA site), and probably caused the retreat of forest cover during these two time intervals. The relatively lower fire activity after 300 cal yr BP until present-day favored the increase of forested area at both TIA and FC sites. The arrival of the European settler and the subsequent introduction of cattle, is suggested as the main reason for the decrease of fire in the study region. The results point the fire caused by indigenous people as the principal controlling factor for forest and savanna dynamics during the past 1550 years.

Reproductive and economic impact following controlled introduction of cattle persistently infected with bovine viral diarrhea virus into a naive group of heifers

The reproductive impact following controlled introduction of animals persistently infected (PI) with bovine viral diarrhea virus (BVDV) was evaluated in BVDV-naive heifers. Heifers were randomly allocated into two groups: an unexposed control herd (n = 34) and a herd exposed to five persistently infected (PI) animals for 7 mo, beginning 50 days before the breeding season (n = 34). Initiation of the BVDV-challenge was timed to mimic either direct contact with PI calves born in the previous calving season or accidental introduction of PI herd additions prior to the breeding season. The PI animals represented BVDV Types 1a (n = 3), 1b (n = 1) and 2 (n = 1). Two BVDV-free, seropositive bulls were used in each group for 78 days breeding seasons. In both groups, 33 of 34 heifers became pregnant, with similar distribution of fetal ages. Two heifers in each group aborted (etiology undetermined). In addition, one calf was born dead and one calf died 3 days post-partum in the BVDV-exposed group. One calf in the unexposed group died 4 mo post-partum. No calves, including the stillborn calf and the two calves that died prior to weaning, were persistently infected with BVDV. In summary, introduction of PI cattle to a group of BVDV-naive heifers 50 days prior to the breeding season did not negatively impact reproductive performance. To the contrary, the active immunity that developed following field exposure to BVDV provided effective reproductive and fetal protection during the breeding season and subsequent gestations, despite continuous exposure to PI animals until approximately midgestation. Although BVDV can have potentially devastating reproductive effects, timing of infection is a critical determinant in the outcome of a BVDV infection. A controlled breeding season with introduction of herd additions at less critical reproductive time points can mitigate the negative reproductive health consequences of BVDV.

Risk factors for Psoroptes ovis mange on Belgian Blue farms in Northern Belgium

The parasitic mite Psoroptes ovis causes important economic losses in Belgian Blue cattle. Because mange problems vary significantly between farms, a cross-sectional questionnaire survey and subsequent farm visits were performed to identify potential risk factors for P. ovis infections on Belgian Blue farms in Flanders, Belgium.The questionnaire was sent to 1800 beef farms to evaluate the presence and severity of psoroptic mange in the herd and to assess farm management practices, including antiparasitic treatments. Subsequently, about 10% of the farms with a completed questionnaire were visited to validate the questionnaire and to retrieve supplementary information on additional management parameters, such as barn infrastructure and climate. Associations between parasitism and putative risk factors were assessed by logistic regression.Out of 1800 contacted farms, 680 (38%) completed questionnaires were received. Data were collected from 238 barns during 66 farm visits. The questionnaire results demonstrated a high farm prevalence of mange (74%; 95% CI (70.7–77.3)) and half of the farmers declared that the problem was difficult to control. Nevertheless, in only 14% of the barns a high scratching index was recorded and in most of the sampled animals (80%) the affected body surface was less than 10%. This indicates that despite the high prevalence and the difficulty to control the infection, clinical signs were often quite moderate.Logistic regression analyses of the questionnaire and the farm visit data suggested that heavily infested farms treat more intensively against mange. On most farms mange occurred the whole year round and more problems with mange were found on farms where a higher number of animals were purchased per year. In addition, the disease was more prevalent when the animals had a lower hygiene score. This score was strongly correlated with environmental hygiene, indicating that transmission of mites from the environment to the animals should not be underestimated. Conflicting results were obtained on the effect of supplementing minerals on the occurrence of mange. In this study, temperature, light intensity and relative humidity in the barns, ventilation systems, barn infrastructure, animal stocking rate and blood mineral levels were not indicated as risk factors for mange. In conclusion, maintaining a good animal hygiene and if possible, avoiding introduction of cattle may help to control psoroptic mange in Belgian Blue cattle.

Huellas y paisajes de la ganadería en el territorio uruguayo

The development of cattle farming has influenced and modeled the social and economic organization of Uruguay along history and has culturally acquired several expressions, including decisive evidence in the historical organization of its territory and the conformation of its rural landscape. The historic marks of cattle farming are key to understand the logics of land use planning and the natural-culturalconstruction of the Uruguayan landscape and have exerted great influence on the country’s internal policy organization, the division of land, the organization of roads and trails, its toponymy, etc. From the modifications of flora and fauna caused by the first introduction of cattle in the country, the conformation of the rural landscape of our territory has been linked to cattle farming, especially to the economic unit represented by the “estancia ganadera” (cattle farm). Its historic evolution delineated processes for land occupancy, holding and exploitation which lasted very long periods and with the so called “modernization of cattle farming” established the way and typology of rural architecture as well as forestry treatment and equipment which defined the predominant profile of rural areas in the country. The estate systems related to the industrialization of meat, which resulted from the productive situation of the country in the 70’s are also as significant, although their territorial dimension is much less. These industrial remains (unequally preserved, recognized and restored) require to be approached as cultural landscapes and demand the set up of their links with the territory and the productive chain. This approach focuses on recognizing and activating the most significant elements of this cultural heritage, integrating its management to cattle farming today and to sustainable strategies of local and regional productive development.

Subterranean Behavior and Other Notes for Ironoquia plattensis (Trichoptera: Limnephilidae) in Nebraska

Abstract Ironoquia plattensis Alexander & Whiles (Trichoptera: Limnephilidae) was discovered along the Platte River in central Nebraska in the late 1990s, and basic information about its life history is not well understood. Here, we describe previously undocumented life-history traits that demonstrate strategies used by I. plattensis for surviving in fluctuating wetland environments in a landscape formally shaped by flooding. In an off-channel aquatic habitat along the Platte River, we observed 1) larvae residing in a slough that did not dry completely, 2) larvae emigrating from aquatic to terrestrial habitats 1 mo earlier than reported previously, 3) larvae moving above ground during the summer aestivation period, 4) larvae residing underground in soil during summer aestivation, and 5) mass emergence and swarming of adults after daybreak in autumn. Underground larval aestivation represents a previously undocumented behavior for this species. It is unclear whether aestivating underground represents an unreported common behavior or an infrequent response to local disturbances. At our site, insects may have been responding to a prescribed burn in April and introduction of cattle in mid-May that yielded the site unsuitable for aboveground aestivation. Additional studies on the life history for I. plattensis are warranted to help manage, locate, and protect the few sites where it occurs.

Risk factors for elevated Enterococcus concentrations in a rural tropical island watershed

Associations were examined between riparian canopy cover, presence of cattle near streams, and month of year with the concentration of Enterococcus (Most Probable Number (MPN)/100 ml) in surface water at Waipā watershed on the North Side of the Hawaiian island Kaua’i. Each one percent decrease in riparian canopy cover was associated with a 3.6 MPN/100 ml increase of waterborne Enterococcus. Presence of cattle near monitoring sites was associated with an increase of 99.3 MPN/100 ml of Enterococcus in individual grab samples. Lastly, summer samples (July) were substantially higher in concentration of Enterococcus than winter collected samples (February) in Enterococcus in sampled streams. These results suggest that reducing canopy cover and introduction of cattle into riparian zones may contribute to increases of Enterococcus concentrations in stream water.

Origin and Diversification of Dung Beetles in Madagascar.

Madagascar has a rich fauna of dung beetles (Scarabaeinae and Aphodiinae) with almost 300 species described to date. Like most other taxa in Madagascar, dung beetles exhibit an exceptionally high level of endemism (96% of the species). Here, we review the current knowledge of the origin and diversification of Malagasy dung beetles. Based on molecular phylogenies, the extant dung beetles originate from eight colonizations, of which four have given rise to extensive radiations. These radiations have occurred in wet forests, while the few extant species in the less successful radiations occur in open and semi-open habitats. We discuss the likely mechanisms of speciation and the ecological characteristics of the extant communities, emphasizing the role of adaptation along environmental gradients and allopatric speciation in generating the exceptionally high beta diversity in Malagasy dung beetles. Phylogeographic analyses of selected species reveal complex patterns with evidence for genetic introgression between old taxa. The introduction of cattle to Madagascar 1500 years ago created a new abundant resource, onto which a few species have shifted and thereby been able to greatly expand their geographical ranges.

Araucaria forest dynamics in relation to fire frequency in southern Brazil based on fossil and modern pollen data

To elucidate the relationship between forest dynamics and fire frequency pollen percentages and charcoal amounts from a 120 cm long peat core and from samples of modern pollen rain were collected along a transect. The study site in southern Brazil is characterized by a species-rich mosaic of grassland– Araucaria forest. It is of crucial importance for management strategies for conservation to understand the development and maintenance of these vegetation mosaics including their sharp forest–grassland boundaries. During the late Holocene, considerable changes occurred in the area. From Anno Domini (AD) 1360 to 1410, the area was dominated by Campos (grassland) vegetation and fire was very common. From AD 1410 to 1500, Araucaria forest expanded and fire was less frequent. From AD 1500 to 1580, Campos grassland spread and the Araucaria forest ceased its development, apparently due to the increase of fire. From AD 1580 to 1935, after a decrease in fire frequency, Araucaria forest expanded again. From AD 1935 to the present, the Araucaria forest expanded while the Campos area decreased. Fire was very rare in this period. The results indicate a strong interaction of forest expansion, forming a mosaic of Campos and Araucaria forest, and the frequency of fire during the past 600 years. A possible collapse of the indigenous population following the post-Colombian colonization in southern Brazil after about AD 1550 may have caused a great reduction of fire frequency. The introduction of cattle (probably after AD 1780) and the resulting decrease of fire frequency might be the reason for forest expansion. Fire is probably the most important factor controlling the dynamics of the forest–grassland mosaics and the formation of sharp borders between these two vegetation types.

Spatial and temporal land cover changes in Terminos Lagoon Reserve, Mexico

Terminos Lagoon ecosystem is the largest fluvial-lagoon estuarine system in the country and one of the most important reserves of coastal flora and fauna in Mexico. Since the seventies, part of the main infrastructure for country's oil extraction is located in this area. Its high biodiversity has motivated different type of studies including deforestation processes and land use planning. In this work we used satellite image analysis to determine land cover changes in the area from 1974 to 2001. Our results indicate that tropical forest and mangroves presented the most extensive losses in its coverage. In contrast, urban areas and induced grassland increased considerably. In 2001 more than half of the ecosystem area showed changes from its original land cover, and a third part of it was deteriorated. The main causes of deforestation were both the increase in grassland and the growth of urban areas. However, deforestation was attenuated by natural reforestation and plant canopy recovery. We conclude that the introduction of cattle and urban development were the main causes for the land cover changes; however, the oil industry activity located in the ecosystem, has promoted indirectly to urban growth and rancher boom.

Evaluation of progress made by dairy and beef herds enrolled in the Minnesota Johne's Disease Control Program

To evaluate progress made by cattle herds in the control of paratuberculosis (Johne's disease) through participation in the Minnesota Johne's Disease Control Program (MNJDCP). Retrospective records analysis. Data for dairy and beef herds participating in the MNJDCP. Data for the MNJDCP were collected for analyses. Outcome measures included changes in numbers of participating cattle producers, risk assessment scores, and within-herd seroprevalence of Johne's disease by year of program participation. Results revealed steady increases in program participation by cattle producers in Minnesota over time, with > 30% of dairy producers and 2% of beef producers in the state participating by the end of 2006. Despite risk of introduction of Johne's disease to cattle herds through continued introduction of cattle from other herds, dairy and beef herds in the Management Program of the MNJDCP reduced their on-farm risk assessment scores during the program. Dairy herds in the Management Program reduced their mean within-herd seroprevalence 1.1% during the first year, 2.6% during the first 2 years, and 4.0% during the first 3 years of program participation. Significant within-herd seroprevalence reduction was also detected for beef herds that participated in the Management Program for at least 3 years. This study revealed a reduction in the risk of withinherd transmission of Johne's disease and seroprevalence over time in dairy and beef herds in the Management Program of the MNJDCP. This is consistent with a positive effect of the program for the control of Johne's disease in cattle.

Consequences of cattle introduction in a shrubsteppe ecosystem: indirect effects on desert horned lizards (Phrynosoma platyrhinos)

Abstract Livestock grazing is one of the most common forms of land use in the western United States, yet scientists struggle to accurately predict grazing impacts. This study examined the initial response of desert horned lizards (Phrynosoma platyrhinos) to cattle introduction at a site in northwestern Utah. We sampled 21 grazed and 7 ungrazed study plots before grazing (2001), after grazing (2002), and 1 year after the cessation of grazing (2003). We were specifically interested in whether grazing influenced lizards through biotic or abiotic pathways. Lizard response (based on scat counts) to the initial impact of grazing (<6 months after cattle introduction) suggests that lizards abandoned areas protected from grazing (i.e., ungrazed exclosures) presumably in favor of grazed areas. Avoidance of ungrazed plots by lizards coincided with a decline in shrub and grass cover on grazed plots and with no significant change in relative abundance or richness of prey (ants) on grazed plots. In 2003, one year after...

Soil physical responses to cattle grazing cover crops under conventional and no tillage in the Southern Piedmont USA

Grazing of cover crops in grain cropping systems can increase economic return and diversify agricultural production systems, but the environmental consequences of this intensified management have not been well documented, especially under different tillage systems. We conducted a multiple-year investigation of how cover crop management (grazed and ungrazed) and tillage system [conventional (CT; initial moldboard plowing and thereafter disk tillage) and no tillage (NT)] affected soil physical properties (bulk density, aggregation, infiltration, and penetration resistance) on a Typic Kanhapludult in Georgia. Responses were determined in two cropping systems: summer grain/winter cover crop and winter grain/summer cover crop. Soil bulk density was reduced ( P = 0.02) with CT compared with NT to a depth of 30 cm at the end of 0.5 year, but only to a depth of 12 cm at the end of 2, 2.5, and 4.5 years. Grazing of cover crops had little effect on soil bulk density, except eventually with 4.5 years of management. Water-stable macroaggregation was reduced ( P ≤ 0.01) with CT compared with NT to a depth of 12 cm at all sampling times during the first 2.5 years of evaluation. Stability of macroaggregates in water was unaffected by grazing of cover crops in both tillage systems. Across 7 sampling events during the first 4 years, there was a tendency ( P = 0.07) for water infiltration rate to be lower with grazing of cover crops (5.6 mm min −1) than when ungrazed (6.9 mm min −1), irrespective of tillage system. Across 10 sampling events, soil penetration resistance was greater under NT than under CT at a depth of 0–10 cm ( P = 0.001) and the difference was greater in ungrazed than in grazed systems ( P = 0.06). Biannual CT operations may have alleviated any surface degradation with animal traffic, but the initially high level of soil organic matter following long-term pasture and conversion to cropland with NT may have buffered the soil from any detrimental effects of animal traffic. Overall, the introduction of cattle to consume the high-quality cover crop forage did not cause substantial damage to the soil.

Historical Patterns and Drivers of Landscape Change in Colombia Since 1500: A Regionalized Spatial Approach

The extent and the spatial patterns of landscape transformation we observe today are the result of the historic human settlement process, often dating back hundreds or thousands of years. Analyzing and reconstructing those historical patterns helps to advance the understanding of the dynamics and persistence of present-day ecosystems. This article explores this reconstruction by identifying and analyzing historic drivers of landscape change for seven periods between 1500 and 2000, and presents historical land use maps showing major trends and impacts on natural ecosystems. Historic land use maps were built using an ecosystem map of 1998 and a “preclearing” ecosystem map, by constraining the spatial change of transformed areas using data on accessibility to rivers and roads, elevation, slope, moisture availability, and settlement areas. We estimate the transformed area rose from approximately 15 Mha in 1500 to 42 Mha in 2000, and land use changed from cropping in 1500 to predominantly grazing in 2000. Demographic impacts of colonization and the introduction of cattle were major drivers of change, but rates and trends of land cover change varied between regions and from period to period. The most impacted ecosystems have been the Andean and tropical dry forests, with the most recent trends toward clearing of humid lowland forests, especially in the Amazon and Pacific. Some landscapes have been subject to strong human influence continuously for more than 500 years, whereas others have been transformed for less than thirty years. We discuss the relevance of a historical approach for guiding conservation goals, ecological restoration efforts, and research hypotheses.

Vertebrate fossils excavated from the Bol'shoj Naryn site, East Siberia

Located at approximately 53°N, 103°E, the Bol'shoj Naryn site lies on the hills facing Osa Bay, in the Bratsk Reservoir. The authors started excavating this site in 2003. By 2005, we had found 337 stone tools and flakes, and more than 600 animal fossils, from the paleosol layers ( 14C dating: from 25,000 to 32,000 yr BP) deposited in the second half of the Karginian Interstadial. Large specimens of the fossils collected by visual observation were mostly the bones and teeth of Equus sp. and Bovinae, and small specimens obtained through wet sieving included many fossils of Lagurus lagurus, Microtus sp., and Spermophilus undulatus. This suggests that the steppe had spread around this site by the last half of the Karginian Interstadial. However, some of the animal fossils collected from the Bol'shoj Naryn site were characteristic of tundra or forest, as well as steppe. To understand why, remains characteristic of three different habitats were excavated from the same paleosol of the Karginian Interstadial, detailed discussions centered on the radiocarbon age of each material are needed. As part of our investigation of the fossils of large vertebrates, we measured various parts of the fossils of Eanus sp. in excavated specimens and in specimens collected from the reservoir's shore, in accordance with the procedure described by von den Driesch [1976. A Guide to the Measurement of Animal Bones from Archaeological Sites. Peabody Museum of Archaeology and Ethnology Bulletin 1, Peabody Museum, Harvard University, Cambridge, MA]. We inserted the measured values into the formula of Nishinakagawa et al. [1991. A study on the time and the route of the introduction of cattle and horses into Japan, as examined from skeletal remains of archaeological sites. Report of the Grant-in-Aid from the Ministry of Education, Culture, Sports, Science and Technology, Scientific Research (B) 1990 (Japanese, English abstract)] and found that the collected fossils were mostly of individuals with withers heights between 125 and 135 cm. To clarify the time transition, a future project will use measurements to examine the trait characteristics of the fossils of other large mammals. In future, we intend to clarify the histories of nature and humankind in the Pleistocene in the Fore-Baikal region and to add animal fossils excavated from other sites to the scope of our research.