Del Apache National Wildlife Refuge Research Articles

The Role of Migratory Waterfowl as Nutrient Vectors in a Managed Wetland

Dense aggregations of waterfowl, often caused by loss of native wetlands and increased waterfowl numbers, can result in the destruction of wetland vegetation and agricultural crops, increase the risk of infectious disease outbreaks, and decrease water quality. Problems related to water quality may be particularly severe in arid regions of the southwestern United States, where water quality and quantity are contentious issues. Over 40,000 Lesser Snow Geese (Chen caerulescens caerulescens) and Ross’ Geese (Chen rossii) winter annually at Bosque del Apache National Wildlife Refuge, New Mexico. Daily feeding bouts by geese move large quantities of nutrients from farm fields where they feed to managed wetlands where they roost. Using energy and mass balance models, population estimates, daily and seasonal migration patterns, and feeding behaviors, we estimated the mass and ratio of nitrogen to phosphorus of nutrients loaded by geese into the wetlands of the Bosque del Apache National Wildlife Refuge. Loading rates peaked in late November 1995 at more than 300 kg nitrogen per day and over 30 kg phosphorus per day. As feeding behaviors changed through the winter and bird densities declined, loading rates fell. Our estimates suggest that in the winter of 1995–1996, bird‐borne nutrients supplied nearly 40% of the nitrogen and 75% of the phosphorus entering the primary wetland used for geese roosting. High loading rates by geese are a consequence of their colonial roosting behavior; over 90% of the geese roost on 10% of the wetland area. The effects of nutrient loading could be reduced by increasing flushing rates or dispersal of roosting waterfowl. The loss of natural wetlands, however, limits options for expanding wetland area available to waterfowl, and it may be difficult to increase flushing rates in this arid region. Thus, management of waterfowl and the nutrients they move will continue to be an important issue for wetlands of wildlife refuges. El Papel de las Aves Acuáticas como Vectores de Nutrientes en un Humedal Manejado Densas agregaciones de aves acuáticas causadas frecuentemente por la pérdida de humedales nativos y el incremento en el número de ave acuáticas, puede resultar en la destrucción de la vegetación de humedales y cultivos, un incremento en el riesgo de dispersión de enfermedades infecciosas y una disminución en la calidad del agua. Los problemas relacionados con la calidad del agua pueden ser particularmente problemáticos en regiones áridas del suroeste de los Estados Unidos, en donde la calidad y cantidad del agua son temas polémicos. Cerca de 40,000 ganzos Lesser snow (Chen caerulescens caerulescens) y ganzos Ross (Chen rosii) invernan anualmente en el Refugio de vida silvestre Bosque del Apache, en Nuevo Mexico. Diariamente grandes cantidades de nutrientes son trasladadas de las granjas donde los ganzos se alimentan an los humedales donde descansan. Mediante el uso de modelos de energía y balance de masas, estimaciones de la población, patrones de migración diaria y estacional y conductas alimenticias, estimamos la masa y proporción nitrógeno:fósforo de los nutrientes descargados por los ganzos en los humedales del Bosque del Apache. Las tasas de descarga tuvieron picos al final de Noviembre de 1995 de> 300 kg de nitrógeno y> 30 kg de fósforo por dia. Como la conducta alimenticia cambió a lo largo del invierno y las densidades de aves disminuyeron, las tasas de descarga cayeron. Nuestras estimaciones sugieren que en el invierno de 1995–1996 los nutrientes de origen avícola aportaron cerca del 40% del nitrógeno y 75% del fósforo que entró al humedal mayormente utilizado por los ganzos para descanso. Altas tasas de descarga por ganzos son consecuencia de su conducta de descanso en colonias;> 90% de los ganzos descanzó en solo 10% del área del humedal. Los efectos de descarga de nutrientes podrían ser reducidos incrementando las tasas de flujo o la dispersión de las aves en descanzo. La pérdida de humedales naturales limita de cualquier manera las opciones para expander el área de humedal disponible para las aves, además de que un incremento de las tasas de flujo puede ser dificil en esta árida región. Por lo tanto, el manejo de las aves y los nutrientes que mueven continuará siendo un problema importante para los humedales en refugios de vida silvestre.

Restoration of Saltcedar (Tamarix spp.)-Infested Floodplains on the Bosque del Apache National Wildlife Refuge

Vegetation development bordering the Middle Rio Grande, as with most major southwestern U.S. tributaries, has historically undergone rapid and dynamic change. The introduction of saltcedar (or Tamarisk, genus Tamarix) and other exotic species into this environment within the 20th century has contributed to this process. These plants are now an integral component of the riparian vegetation mix. Manpower, logistics, and financial resources constrain the degree to which a desired riparian habitat can be restored from saltcedar thickets on the Bosque del Apache National Wildlife Refuge near Socorro, NM. Saltcedar clearing is accomplished using a combination of herbicide, burning, and mechanical control techniques costing from $750 to $1,300/ha. Soil salinity and depth to water are the principal physical features limiting revegetation efforts. Cottonwood and black willow plantings and natural regeneration after timed irrigations have produced diverse habitats that support a wide array of faunal species in areas previously occupied by homogeneous saltcedar.

Effects of an experimental flood on litter dynamics in the middle rio grande riparian ecosystem

AbstractThe objectives of the study were to measure the effects of an experimental flood on : (1) leaf litter production by the riparian forest; (2) leaf decomposition; and (3) the amount of forest floor organic matter. The study area is located at Bosque del Apache National Wildlife Refuge, approximately 160 km south of Albuquerque, New Mexico. Experimental and reference study sites of about 3·1 ha were both located in cottonwood (Populus fremontii) riparian forests that had not been flooded for approximately 50 years. The experimental and control study sites were sampled for two years before flooding the experimental site. The experimental flood peaked on about 31 May, the average date of peak flow in the 100 year hydrograph for the USGS gauging station on the Rio Grande at Embudo, New Mexico. Litter fall was lower at the flood site than at the control site, whereas the rate of leaf decomposition was higher at the flood site during the period of inundation. However, the flood did not produce a measurable response in standing stock of forest floor litter. This pool of carbon may require the cumulative effects of several years of flooding to show a measurable response.

Rapid Salinity Mapping by Electromagnetic Induction for Determining Riparian Restoration Potential

AbstractThe feasibility of measuring soil salinity with electromagnetic induction (EM) for determining riparian restoration potential was investigated on a 28‐hectare plot at the Bosque del Apache National Wildlife Refuge in central New Mexico. The plot was cleared of exotic Tamarix chinensis (saltcedar), surveyed and gridded into 1370.2 hectare sections. Soil samples and EM measurements were taken at each section. We compared laboratory‐determined ECe values from the soil samples with ECa values calculated from the EM measurements using a model developed by Rhoades et al. (1990). Direct comparison of ECe values determined from the two methods yields a low correlation due to sample‐size differences but the calculated ECa was able to accurately predict whether the measured ECe would lie above or below some threshold value. An assessment of general site suitability for riparian restoration with electromagnetic induction has proven to be a rapid, accurate, and cost‐effective alternative to intensive soil sampling.

Persistence of the Meadow Jumping Mouse, Zapus hudsonius luteus, in New Mexico

Zapus hudsonius luteus is a subspecies of the meadow jumping mouse (Hafner et al., 1981) that is restricted to New Mexico and Arizona, where it occupies mesic habitats in lowland valleys and along montane streams (Bailey, 1913; Findley et al., 1975; Hafner et al., 1981; Hoffmeister, 1986). The subspecies has been reported from 14 localities in New Mexico (Hafner et al., 1981; R. D. Ohmart and V. C. Hink, in litt.) and 11 localities in Arizona (Hafner et al., 1981; Hall, 1981; Hoffmeister, 1986). In New Mexico, these records are from the San Juan Mountains (El Rito area), Sangre de Cristo Mountains (North Williams Lake), Jemez Mountains (upper Guadalupe River drainage), Sacramento Mountains (Rio Penasco and Silver Springs Creek), and the Rio Grande Valley (Espanola to the Bosque del Apache National Wildlife Refuge; Fig. 1). Southwestern populations of the genus Zapus were initially described by Miller (1911) as a distinct species, Zapus luteus, then as a subspecies of the western jumping mouse, Zapus princeps (Z. p. luteus), by Krutszch (1954). Based on genetic relationships between southwestern Zapus and other representatives of the genus, Hafner et al. (1981) concluded that these peripheral isolates were instead conspecific with the meadow jumping mouse, Z. hudsonius, and, therefore, considered them to be Z. h. luteus.

Urbanization and the Middle Rio Grande Conservancy District

A shift from irrigation agriculture to urban landuses is affecting physical and social aspects of the Middle Rio Grande Conservancy District. An evolutionary perspective and an examination of special districts provide a framework for understanding the significance of changes occurring in the district. The district was intended to have three benefits: flood control, supply of irrigation water, and drainage. The latter two have been profoundly affected by the shift to urbanization. QPECIAL districts have been created in many areas of the West to provide LI water-related services such as irrigation, food control, drainage, or a combination of purposes. Many districts that originally served rural populations have been progressively urbanized. The process of urbanization affects the social and physical environments of a district. The purpose of this study is to examine how change from rural to urban landuses has influenced and continues to affect the Middle Rio Grande Conservancy District (MRGCD) in New Mexico. The text is organized in three parts. The first is a historical examination of the creation of the MRGCD; the second is a discussion of characteristics of special governmental districts to establish a base for evaluating changes in the district; the third is an examination of the process of urbanization and its direct and indirect influences on certain social and physical aspects of the district. The middle section of the Rio Grande drainage basin is the focus of this study-specifically the portion served by the MRGCD.1 It extends 240 kilometers south from Cochiti Dam to the northern boundary of the Bosque del Apache National Wildlife Refuge and varies from two to eight kilometers in width (Fig. 1). The district encompasses 112,463 hectares, including 11,540 hectares of Indian lands. Of the total area, 52,145 hectares are considered potentially irrigable, although only 35,200 hectares, or approximately 68 percent of the total, are currently irrigated. On the bases of archaeological evidence, observations from early Spanish explorers, and certain assumptions about the ratio of Indian population to irrigated land, it has been estimated that 10,000 to 12,000 hectares were irrigated in 1539 when the Spanish explorer Antonio de Espejo entered the region.2 Spanish settlers brought with them during the sixteenth and seventeenth centuries a social structure for hydraulic community organization.3 I National Resources Committee, Regional Planning, Part VI: The Rio Grande Joint Investigation in the Upper Rio Grande Basin in Colorado, New Mexico and Texas (Washington, D.C.: Government Printing Office, 1938). 2Joseph L. Burkeholder, Report of the-Chief of Engineers: Vol. 1, Middle Rio Grande Conservancy District, Albuquerque, N.M., 1928. 3Arthur Maass and Raymond L. Anderson, ... And the Desert Shall Rejoice: Conflict, Growth, and Justice in Arid Environments (Cambridge, Mass.: MIT Press, 1978). * DR. THOMPSON is an assistant professor of geography at the University of New Mexico, Albuquerque, New Mexico 87131. This content downloaded from 157.55.39.144 on Wed, 07 Sep 2016 06:43:41 UTC All use subject to http://about.jstor.org/terms 36 THE GEOGRAPHICAL REVIEW