Raul Valdez

Evaluation of microhistological analysis for determining ruminant diet botanical composition.

The accuracy of microhistological techniques for analysis of herbivore diets was evaluated with cattle, sheep, and Angora goats fed grass, forb, and shrub mixtures of known botanical compositions. Two observers performed microhistological analyses on undigested diets as offered and on feces collected. Similarity indices and chi-square tests were used to determine if differences existed among actual diets, estimated diets, and fecal samples. Botanical compositions of diets fed to all 3 animal species generally were accurately estimated by fecal analyses. In some other studies, shrubs in ruminant diets have been inaccurately estimated by the microhistological technique. However, in our study, shrubs were accurately estimated with no differences between actual and observed compositions. We attribute this to the fact that shrub materials used in our study had a high proportion of current growth relative to woody materials. Woody plant parts had lower proportions of identifiable epidermal material than leaves and young stems. In grass-forb diets, forbs sometimes were overestimated and differentiation among grasses was difficult. However, in most cases, observers could precisely estimate diets of the 3 herbivore species.

Influence of native shrubs on nutritional status of goats: nitrogen retention.

In vivo digestibility trials were conducted to evaluate the influence of shrubs containing low and high levels of soluble phenolic/tannins on digestibility and nitrogen retention by Angora goats. Each of 6 shrubs and alfalfa hay (Medicago sativa L.) were fed to goats at 30% (dry matter basis) of the diet in a barley straw-prairie hay mixture. The mixture was regulated so that all diets contained about 8% crude protein. High soluble phenolic shrubs used included big sagebrush (A rtemisia tridentata Nutt. ssp. tridentata), gray oak (Quercus grisea Liebm.), true mountain mahogany (Cercocarpus montanus Raf.), and one-seed juniper (Juniperus monosperma [Engelm.] Sarg). Low-soluble phenolic species included common winterfat (Ceratoides lanata [Pursh.], J.T. Howell), fourwing saltbush (A triplex canescens [Pursh.], Nutt.), and alfalfa. Nitrogen digestibilities of winterfat, gray oak, mountain mahogany and one-seed juniper diets were less (P .05) compared with the alfalfa control. Retained nitrogen (g/d) differed (P<.05) only among alfalfa, juniper, and mountain mahogany diets. Goats fed juniper had greater (P<0.05) retained nitrogen than the alfalfa control. Shrubs high in soluble phenolics, with the exception of big sagebrush, had elevated fecal nitrogen losses, but reduced urinary nitrogen losses compared with the alfalfa control. Forage organic matter intake (% body weight) and nitrogen intake (g/d) were correlated more highly with nitrogen retention than dietary crude protein (%) or digestible protein (%). Present data indicate that protein found in palatable native shrubs is assimilated with similar efficiency to that in alfalfa hay if these shrubs are consumed at

Wildlife Conservation and Management in Mexico

Abstract Mexicos wildlife has been impacted by human land use changes and socioeconomic and political factors since before the Spanish conquest in 1521. Presently, it has been estimated that more than 60% of the land area has been severely degraded. Mexico ranks in the top 3 countries in biodiversity, is a plant and faunal dispersal corridor, and is a crucial element in the conservation and management of North American wildlife. Wildlife management prerogatives and regulatory powers reside in the federal government with states relegated a minimum role. The continuous shifting of federal agencies responsible for wildlife management with the concomitant lack of adequate federal funding has not permitted the establishment of a robust wildlife program. In addition, wildlife conservation has been further impacted by a failure to establish landowner incentives, power struggles over user rights, resistance to change, and lack of trust and experience in protecting and managing Mexicos wildlife. We believe future strategies for wildlife programs must take into account Mexicos highly diversified mosaic of ecosystems, cultures, socioeconomic levels, and land tenure and political systems. The private sector, along with communal properties, in cooperation with federal and municipal governments, nongovernmental organizations, corporations, and international agencies may have the greatest potential of sustainable management of Mexicos wildlife. The present federal wildlife management strategy is an initial positive effort because it promotes participatory wildlife conservation by key stakeholders. We identify the aspects of this strategy that we believe will be needed to establish a sustainable program to manage Mexicos wildlife.

Magnification and shrub stemmy material influences on fecal analysis accuracy.

When 100X and 200X microscope magnification levels were used singly and interchangeably in microhistological analysis, magnification level had no effect (K.05) on diet botanical composition of 60% grass and 60% forb diets containing 6 forage species fed to mule deer. However, hrrge differences occurred between magnification levels for individual plant species in a 60% shrub diet containing the same forage species. The use of the 100X and 200X magnification levels interchangeably was slightly more accurate than exclusive use of either magnification level for the high grass and high shrub diets. For fecal analysis our study shows 100X and 200X microscope magnification levels can be used singly or interchangeably with little influence on accuracy. Use of the 100X magnification level to scan fields for potentially identifiable fragments followed by switching to 200X magnification for better resolution of fragments difftcult to discern can slightly improve both speed and accuracy. Fourwing saltbush, which had a high proportion of stemmy material relntive to leaves, was severely underestimated in the feces of all 3 diets. Our data indicate fecal analysis has limited value as an estimator of diets of herbivores, such as mule deer, that consume significant but variable quantities of stemmy material from shrubs. Fecal analysis has become one of the most widely used tools to evaluate the botanical composition of wild herbivore diets. While degree of magnification in fecal analysis studies has consistently been 100X or 125X, higher levels of magnification might improve the accuracy of fecal analysis. Fecal analysis may have severe limitations for estimating diets of herbivores consuming varying quantities of woody material during the year (Zyznar and Urness 1969, Westoby et al. 1976). The objectives of this research were to determine the similarity between actual mule deer diets and fecal samples when the 100X and 200X microscope magnification levels were used singly and interchangeably for estimating the botanical composition of fecal samples. Because the 3 diets used in this study contained different levels of shrub stemmy material, its influence on fecal analysis accuracy could be evaluated. Methods

Jackrabbit densities on fair and good condition Chihuahuan desert range.

This study was conducted on Chihuahuan desert range near Las Cruces, in southcentral New Mexico, to determine the relationship of blacktailed jackrabbit (Lepus californicus) densities to good (GC) and fair (FC) range condition. The Soil Conservation Service procedure was used to classify ecological range condition. Line transect procedures were used to estimate jackrabbit populations from July 1988 to December 1990. Concurrently vegetation cover and mean plant height were determined with the line intercept procedure. Jackrabbit densities on the fair condition range were higher (P < 0.10) than those on the good condition range. This difference is attributed to the fair condition range containing more protective cover and preferred forage than good condition range. Jackrabbit abundance showed no season (P < 0.10) or year differences (P < 0.10). Jackrabbits preferred grass-shrub mosaic habitats more than shrubland and grassland habitats. The need for diverse food sources and protective cover were apparently major determinants of habitat selection by jackrabbits. The good condition range contained greater (P < 0.10) grass cover and less (P < 0.10) shrub cover than the fair condition range. Our results indicated that maintaining Chihuahuan desert ranges in good to excellent condition is the best means of achieving lower abundance of jackrabbit populations.

Range condition influences on Chihuahuan Desert cattle and jackrabbit diets

Knowledge of comparative diet selection by cattle and black-tailed jackrabbits (Lepus californicus) would permit better estimation of grazing capacity on Chihuahuan desert ranges. Cattle and black-tailed jackrabbit diets were evaluated seasonally on good and fair condition ranges over a 2-year period. Fecal samples analyzed by the microhistological technique were used to determine diets of both animals. Key forage species in cattle diets were dropseeds (Sporobolus sp.), black grama (Bouteloua eriopoda Torr.), leatherweed croton (Croton pottsii Lam.), and bush muhly (Muhlenbergia porteri Scribn.). Key forage species in jackrabbit diets were honey mesquite (Prosopis glandulosa Torr.), cactus (Opuntia sp.), dropseed, broom snakeweed (Gutierrezia sarothrae Pursh.), and black grama. Overall diet botanical composition data showed cattle consumed 58% grass compared to 22% for jackrabbits (P < 0.05). Forb consumption was similar between the 2 animals and averaged about 31%. Shrub consumption averaged 47% and 12% for jackrabbits and cattle, respectively (P < 0.05). Range condition did not influence total grass consumption by either animal. Both animals, however, had lower forb and higher shrub consumption on fair compared to good condition range. Overall dietary overlaps between jackrabbits and cattle were 40 and 42% on good and fair condition ranges, respectively. Poisonous plants contributed up to 14 and 36% of cattle and jackrabbit diets, respectively. Data from this study show little forage competition occurs between cattle and jackrabbits when stocking rates and jackrabbit numbers are moderate. Several plants poisonous and unpalatable to cattle were important jackrabbit foods. These plants were more prevalent on the fair compared to the good condition range.

Evaluation of fecal indicators for assessing energy and nitrogen status of cattle and goats.

In vivo digestibility trials involving cattle (steers) and goats (wethers) fed shrub and nonshrub mixtures were conducted to evaluate the potential of fecal output, fecal nitrogen output, and fecal nitrogen percent for assessing diet intake, nitrogen balance, and digestibility. Two cattle digestion trials involving 8 feeds and 4 goat digestion trials involving 13 feeds were used to develop simple linear and multiple regression equations between fecal and diet characteristics. Crude protein percent (organic matter basis) of cattle diets ranged from 3.9 to 12.0%; that of goats ranged from 7.5 to 14.4%. Low-phenolic and high-phenolic shrubs were fed in separate diets to goats while cattle diets involved only low-phenolic shrubs. Fecal output of organic matter (percentage of body weight) was correlated (r2>0.80) with forage organic matter intake (percentage of body weight) for both cattle and goats when all feeds were included in the regression. Linear regression intercepts, but not slopes, differed (P<0.05) among cattle and goats. Multiple regression equations did not improve evaluation of forage intake over simple linear equations using fecal output. Fecal nitrogen output (g N/kg BW) was associated more closely with nitrogen balance (g N/kg BW) than other fecal indicators. Further, fecal N output was best associated with nitrogen balance for both cattle and goats (r2 = 0.64, 73, respectively) when used in multiple regression equations. Multiple regression equations showed potential for evaluating nitrogen intake (g N/kg BW) of both cattle and goats, (R2 = 0.91, 0.87, respectively). Although it is doubtful that our equations have broad applications, our approach might be useful if specific equations were developed for individual range types.

Changing Hispanic demographics: challenges in natural resource management

Abstract Hispanics are a growing segment of the United States population and will be an increasingly important stakeholder in future allocation and management of natural resources, including wildlife. In the United States, Hispanics now are the largest ethnic minority and will remain so over the next 40 years. Texas supports the second-largest Hispanic population in the United States behind California, and it will have a Hispanic majority by 2040. Some analysts predict that this demographic shift will leave us with a less-educated population with smaller incomes and higher levels of poverty—posing not only a social concern but also a challenge for conservation of wildlife resources. Here we identify shared Hispanic cultural characteristics, such as family, socioeconomic factors, and language, and their importance in planning wildlife outreach programs. Recognizing differences among Spanish-speaking cultures is equally important. Knowledge of cultural characteristics will enable wildlife advocates to better expose wildlife issues in a manner receptive by Hispanics. It is in the best interest of wildlife and wildlife professionals to encourage Hispanic participation in this planning process because of their growing political and economic influence.

The Role of Landowners in Jaguar Conservation in Sonora, Mexico

The northernmost known breeding population of jaguars occurs in the municipality of Nácori Chico, Sonora, Mexico about 270 km from the United States-Mexico border and may be the source from which jaguars sighted in the United States dispersed. Since 1999 at least 11 jaguars (Panthera onca) had been illegally killed in the area due to predator control programs. We initiated a jaguar landowner-based conservation plan in 2004. The eight participating landowners agreed to suspend predator control programs targeting jaguars and pumas (Puma concolor) only if cattle losses were compensated. A private outfitter, with the consent of landowners, initiated white-tailed deer (Odocoileus virginianus) hunts in 2004 and agreed to pay the group of participating landowners US

Multispectral and Texture Feature Application in Image-Object Analysis of Summer Vegetation in Eastern Tajikistan Pamirs

1500 for every deer hunt permit sold. The funds paid to the landowners from deer hunts were sufficient to convince landowners to suspend all predator-control efforts of jaguars and pumas. The involvement of landowners in the jaguar conservation program in northeastern Sonora is a successful, private, wildlife-conservation initiative that provides an example for jaguar conservation efforts in northern Mexico.