Sandra Aparecida Santos

NICHE PARTITIONING AMONG WHITE-LIPPED PECCARIES (TAYASSU PECARI), COLLARED PECCARIES (PECARI TAJACU), AND FERAL PIGS (SUS SCROFA)

Abstract The introduction of a species into an ecosystem with species already occupying a similar trophic level is predicted to lead to a high degree of niche overlap. The feral pig (Sus scrofa), one of the worlds worst invasive species, was introduced to the Pantanal about 200 years ago and is thought to compete with the native white-lipped peccary (Tayassu pecari) and collared peccary (Pecari tajacu). Resource partitioning between the 3 species was examined, including analysis of fruit items and plants in fecal samples as well as encounter rates in different habitats, to help generate hypotheses about competitive interactions among the species. Overlaps in food resources and habitat use between feral pigs and peccaries were found to be lower than expected. In fact, niche overlap was highest between the native species. Results indicate that currently, feral pigs are not a direct threat to the native peccaries in the study area. Differences in morphology and behavior indicate possible mechanisms of niche partitioning between the species. Feral pigs may, nevertheless, impact the wildlife community in other ways as predators of eggs, by destruction of vegetation through rooting, or by functioning as disease reservoirs. Cattle-ranching activities may favor feral pigs and the current anthropogenic changes in the landscape could lead to changes in competitive dynamics between feral pigs and native species.

Avaliação dos Fatores que Influem nas Medidas Lineares do Cavalo Pantaneiro

The objective of this work was to evaluate the effects of sex, sub-region, age at registration and year of registration, on 15 linear measures (withers height, back height, croup height, midback height, head length, neck length, back-loins length, croup length, shoulder bone length, body length, head width, chest width, hip width, thorax perimeter and shin bone perimeter) of the Pantaneiro horse. Data from 1214 animals were used, registered in the Brazilian Pantaneiro Horse Association, from 1972 to 1991, and analyzed using GLM, PRINCOMP and CORR procedures of SAS and grouping procedures of the GENES program. The sex, animal age at registration, sub-region and year of registration were significant sources of variation for most of the characteristics studied. The animals of the Corumba region were in general larger than the animals from the other regions. Morphological measures should be taken on the animals from 4 years of age. Correlations between hip height, back height and shoulder height were high and positive, but between other measures were medium to low. Using the grouping method there are several grouping of animals by type which need to be further investigated.

Genetics of the Pantaneiro horse of the Pantanal region of Brazil

Genetic variation at seven red blood cell alloantigen, blood group loci and 10 biochemical genetic loci was examined in 102 Pantaneiro horses from the Pantanal region of Brazil and compared to that of other domestic horse breeds. Measures of both individual genic variation and populational genetic diversity within the Pantaneiro were near the average for domestic horse breeds. From the standpoint of genetic conservation there is no immediate concern for loss of variation within the Pantaneiro. Analysis of genetic relationship showed that the Pantaneiro was clearly of Iberian Peninsula descent and that it was most closely related to other Brazilian breeds.

Using nonlinear models to describe height growth curves in Pantaneiro horses.

Height at withers data mostly from birth to 36 months of age of 26 Pantaneiro horses were used to fit Brody, Richards, Gompertz, Logistic, Weibull and Morgan-Mercer-Flodin nonlinear response functions. Based on measures of average curvature and combined mean square error, the Weibull model was chosen. The asymptote of this curve, representing the average height at maturity, was higher for males than females. The maturity index, however, was more elevated for females than males. There was indication of a negative association between the maturity index and height at maturity only for females. These results indicate that females mature earlier. After checking for normality and homogeneity of variances within groups (sex) the analysis investigated sex differences via t-tests. A significant difference was detected only for height at birth.

Condição corporal, variação de peso e desempenho reprodutivo de vacas de cria em pastagem nativa no Pantanal

The aim of this study was to evaluate the influence of body condition score (BCS) on reproductive performance of beef cows before and after calving and to evaluate the calving probability using body condition score and weight variation during critical periods of the cow reproductive cycle. From 2001 to 2005, the body condition score was recorded in 248 multiparous cows raised in native pastures, submitted to different supplementation treatments (mineral mixture only - control; dry supplement; liquid supplement and liquid supplement for cow and calves). Weighing and body condition evaluation were made on a 1-9 point scale in August (prepartum period, 60-90 days before parturition) and January (postpartum and reproductive period). A reproduction score was created in function of the body scores in four consecutive years. Except for the treatment, the other factors (body condition score in the prepartum and postpartum periods and cow age) influenced the reproduction score. Thus, the calving probabilities were estimated for all cows. Generalized estimating equations (GEE) were used to evaluate the calving probability in function of the exploratory variables over time. Calving probability higher than 80% was obtained when cows scored 5,5 before calving. In relation to weight, the results showed that about 60% of calving cows maintained or gained weight in the postpartum period, leading to increase in the rebreeding probability. Similar situation occurred with single cows; however, the calving probability was lower. These results indicate that the calving probability using BCS is better estimated before calving. Furthermore, it indicates the presence of cows more adapted to the Pantanal climatic and feeding conditions than others.

Composição Botânica da Dieta de Bovinos em Pastagem Nativa na Sub-Região da Nhecolândia, Pantanal

This study aimed to identify the botanical composition of the diet of cattle extensively raised on native grasslands in the Pantanal wetland through the fecal microhystological technique, on a characteristic area of the subregion of Nhecolândia, from October/97 to September/99, and to verify the variation as affected by month, season, year and physiological condition of cows. A set of 726 microhystological slides was prepared, each slide being an observational unit. Based on distribution of maximum occurrence values of each species/slide and in the quantis, the species were classified into four main groups: 1- principal (max >20.0%); 2- medium superior (12.3% <max<=20.0%); 3- medium (6.7<max<=12.3%); 4-occasional (max<+6.7%). These groups represented 11%, 14%, 25% and 50% of the identified species, respectively. A split-plot in distinct time was adjusted envolving each effect (month, season) and its interactions with physiological condition and hydrological year. For all studied groups there were no significant effects of physiological condition of cows and no interaction of physiological condition with period and year on the mean composition of the diet. There were significant effects of season and year for all groups, however, the interaction season x year was significant only for the occasional group.

Rotational Grazing of Native Pasturelands in the Pantanal: an effective conservation tool

Deforestation and conversion of native habitats to exotic pasture and crops, plus inefficient agricultural and cattle management practices, are placing great pressures on natural resources in the Pantanal and Cerrado. To prevent further deforestation and protect biodiversity, areas already developed for farming and ranching need to be managed more efficiently and profitably, so that economic incentives for additional deforestation are minimized. To that end, the Wildlife Conservation Society (WCS) has been working with rural community partners to promote best-management practices that optimize profitability and efficient use of developed lands, while minimizing pressures on natural resources. To improve pasture conditions and reduce cattle impacts, we evaluated the use of rotational grazing as a management tool by monitoring native pasture and cattle within continuous and rotational grazing areas on a southern Pantanal ranch. Monthly comparisons of the grazing systems showed that forage dry mass in the rotational area was greater compared to that of continuously grazed areas. After 17 months, mean cattle weights were 15% heavier and pregnancy rates 22% higher for the herd using the rotational system. Based on forage allowance estimates, the potential stocking rates of the rotational system were 2 to 6 times higher than rates typical of continuously grazed areas in the Pantanal. Results support the use of rotational grazing in native pasture areas of the Pantanal.

Evaluation of conservation program for the Pantaneiro horse in Brazil

A genealogical analysis of registered Pantaneiro horses was carried out with 3647 males and 6794 females. Of these animals, 50.66% had identified sires and 48.86% identified dams. The number of pedigrees increased over the generations, with higher registration of parents of sires than dams. Two municipalities are responsible for almost 70% of all registers: i) Pocone (Mato Grosso State), where the headquarters of the breeders association is located and ii) Corumba (Mato Grosso do Sul State), where EMBRAPA Pantanal conducts its research. The mean inbreeding was 0.04% and average relatedness was 0.13%. Mean generation interval was 8.20 years. There is moderate to high genetic differentiation between farms (15% of total genetic variation) while between municipalities there is little differentiation. Wrights fixation statistics were calculated and FIS (inbreeding coefficient of individuals relative to the subpopulation) values indicate some heterozygosity between farms but not municipalities, with overall FIT (inbreeding coefficient of individuals relative to the total population) close to zero. The municipalities with the highest number of animals (Pocone and Corumba) import relatively fewer sires (45 and 67% respectively). Genetic indices from genealogical data on the Pantaneiro horse population show that inbreeding is under control.Future breeding plans should include germplasm exchange between municipalities. The conservation program for the Pantaneiro horse has been shown to be successful but careful planning is needed in the future to avoid inbreeding and changes in important breed traits given the increasing interest in the use of the breed in sporting competitions.

Monitoring British Upland Ecosystems With the Use of Landscape Structure as an Indicator for State-and-Transition Models

Abstract Remote sensing and landscape ecology concepts can provide a useful framework for state-and-transition models (STM) in order to quantify thresholds at different scales, and provide useful information for scientists, land managers, and conservationists in relation to resilience management. The overall aim of this research was to develop a spatially explicit STM to quantify thresholds based on the scale of disturbance processes impacting a grazing system. Specific objectives were to develop a conceptual STM framework for upland grazing ecosystems, to quantify spatial dynamics of stable and degraded pastures, and to assess threshold occurrence. Color aerial photography from Armboth Fell in the English Lake District National Park (United Kingdom) was classified into bare rock, dwarf shrub heath (DSH), and grassland/degraded wet heath (GDWH) in four pastures with different degrees of grazing pressure. Vegetation communities from these pastures were combined with soils, climate, and landform data to create a conceptual STM framework. Each pasture was sampled with 2-ha plots to quantify DSH and GDWH spatial structure. The proposed STM consisted of two reference and three alternative states. Low–grazing-pressure areas showed significantly higher percentage of DSH cover with larger contiguous patches and lower patch density than high–grazing-pressure areas. Breakpoints, considered to be thresholds, in mean patch area were identified in our data when DSH percentage cover was < 63% and GDWH, > 77%. The present study has shown the value of a robust, reliable, and repeatable approach to identify landscape dynamics and integrate it with field data to inform a conceptual STM framework for upland grazing ecosystems. It also demonstrates the importance of selecting scales relevant to the predominant disturbance process to test for threshold occurrence, and how this approach can be integrated with current assessment methods for resilience management.

Growth curve of Nellore calves reared on natural pasture in the Pantanal

Weight-age and hip height-age relations of Nellore calves, from birth to 10 months old were fitted using a logistic model including sex and year of birth as fixed effects. Calves and their dams were reared on natural pasture using continuous grazing system. The crude protein content and total digestible nutrients were analyzed for pasture selected by the animals. The weights of the calves were adjusted to 205 days and 365 days. There were no significant effects of sex and birth year on the growth curve parameters, but there were significant effects of sex on hip height. The average weight (a parameter) at 10 months of age was 170 kg and the inflection point was observed at 93.5 days old. When weight-age and hip height-age curves were combined in the same graph, the intersection occurred at 142 days. The number of days to gain 160 kg from birth to 205 days of age (adjusted) and number of days to gain 240 kg from 205 days to slaughter was different between the birth years, which were probably due to the quality of the natural pastures. It is necessary to implement nutritional management strategies such as high quality pasture and/or feeding supplementation for calves once they reach three months of age.