Document: KEI-3-33-2

Nutrient resorption in shrubs growing by design, and by default along a Chihuahuan Desert arroyo.

KILLINGBECK, K.T.* ¹ and W.G.WHITFORD ²

University of Rhode Island, Kingston, RI, 02881, USA ¹
United States Environmental Protection Agency, ORD-NERL, Las Vegas, NV, 89193, USA ²

Abstract:
In the northern stretches of the Chihuahuan Desert, the margins of ephemeral stream channels called arroyos support vegetation dominated by a guild of winter-deciduous shrubs. We measured nitrogen (N), phosphorus (P), and zinc (Zn) resorption efficiency and proficiency in the six dominant species of such a guild in southern New Mexico. Collectively, these six species were no more efficient or proficient at resorbing N and P from senescing leaves than shrubs growing in other environments. However, resorption efficiency and proficiency varied significantly between plants specifically restricted in their distribution to riparian habitats (species growing by design), and those that were not (species growing by default). The two species growing by design (Brickellia laciniata and Chilopsis linearis) were more efficient and proficient at resorbing N than species growing by default (Fallugia paradoxa, Flourensia cernua, Prosopis glandulosa, and Rhus microphylla), and than any other group of plants to which they were compared. In addition to the effects on resorption conferred by whether shrubs grew by design or by default, leaf surface area, specific leaf mass, nutrient concentrations in green leaves, and the ability of fix nitrogen influenced resorption as well.

Keywords: arroyo, Chihuahuan Desert, desert shrubs, nitrogen, phosphorus, nutrient resorption, riparian habitats, senescing leaves

This abstract is being presented at: 9:45 AM in session:
Oral Session #61: Plant Responses to Nutrients.