Informations et ressources scientifiques
sur le développement des zones arides et semi-arides

Accueil du site → Projets de développement → Projets de recherche pour le Développement → 2011 → POPULATION AND COMMUNITY STRUCTURE OF GRASSLAND AND SHRUB-ADAPTED AVIFAUNA OF THE CHIHUAHUAN DESERT AND GREAT PLAINS ECOREGIONS

United States Department of Agriculture (USDA) 2011

POPULATION AND COMMUNITY STRUCTURE OF GRASSLAND AND SHRUB-ADAPTED AVIFAUNA OF THE CHIHUAHUAN DESERT AND GREAT PLAINS ECOREGIONS

Grassland Shrub Avifauna

United States Department of Agriculture (USDA) Research, Education & Economics Information System (REEIS)

Titre : POPULATION AND COMMUNITY STRUCTURE OF GRASSLAND AND SHRUB-ADAPTED AVIFAUNA OF THE CHIHUAHUAN DESERT AND GREAT PLAINS ECOREGIONS

Identification : NM-DESMOND-11H

Pays : Etats Unis

Durée : Oct 1, 2011 à Sep 30, 2016

Domaine : Aquatic and Terrestrial Wildlife ; Wildlife habitats ;Endangered species ; Wild animals ; Wild birds

Partenaire : NEW MEXICO STATE UNIVERSITY 1620 STANDLEY DR ACADEMIC RESH A RM 110 LAS CRUCES,NM 88003-1239

Objectifs
Research in my lab will focus on population and community dynamics of grassland- and shrub-adapted birds : 1) To investigate effects of resource abundance and diversity on avian condition in desert grasslands through feeding trials, resource manipulation and direct examination of diet ; 2) To examine factors that influence seed production across years ; 3) To examine effects of habitat fragmentation and desertification on non-breeding grassland- and shrub-adapted birds, including identifying minimum patch sizes for occupation and threshold levels of shrub encroachment that render a patch unsuitable ; 4) To examine factors influencing burrowing owl productivity and movement patterns across Great Plains.

Descriptif
For any seed manipulation experiments we will, in general, follow our past protocol. This includes establishing a minimum of 36, 0.9 ha plots (30x300 m) on sites with similar elevation, topography and soil type. Plot size and shape may vary according to experimental objectives. The experimental design would include four treatments and one control with six replications of each treatment and the control. Treatments will vary according to experimental objectives (diet, community response, or both). Treatments will consist of 40 kg of a five-seed mixture. All seeds selected for manipulation trials will be native to the study area. The seeds in the five-seed mixture are equally proportioned based on mass (20% of the total weight each seed species). Birds will be mist-netted over seed manipulation plots. A 96-m net line and 2 wing nets will be established along the 200-m border of the targeted plot. Birds within the plot are flushed into nets using a crew of volunteers that spread out across the flush zone at the opposite end of the plot and walk toward the nets clapping their hands and making noise. All birds are banded, measurements of bill morphology, including culmen length, bill depth and width, are taken and stomach flushing is performed. The bird will be induced to regurgitate by flooding the stomach with warm water. Stomach and crop samples are run through a coffee filter and stored in small envelopes. These samples are taken to my lab at New Mexico State University where they are analyzed under a dissecting microscope and all seeds will be counted and identified. Seed production will be examined in relation to climatic conditions and grazing to model potential impacts of grazing on grass and forb seed production in New Mexico. Pastures will have low to high stocking rates (depending on experiment), with similar grazing management and we will control for grazing history. Ideally two sets of paired plots (625m2) will be established within each pasture with a minimum of 16 plots. Each set of paired plots will consist of one grazed plot and a grazing exclosure. An automated weather station is located centrally within each set of paired plots. Burrowing owl study sites are distributed from northwestern Chihuahua, Mexico to western South Dakota. These sites include prairie dog colonies in desert grasslands in Chihuahua, Mexico and southern New Mexico (Engel), the adjacent Kiowa and Rita Blanca National Grasslands in southern plains grasslands of west Texas and eastern New Mexico, two short grass prairie sites, Comanche and Pawnee National Grasslands in southern and northern Colorado, respectively, and two mixed grass prairie sites, Buffalo Gap and the Grand River National Grasslands in western South Dakota. Within each site 12 colonies were randomly selected : 4 each of small (5 - 25 ha), medium (50 - 100 ha) and large (> 150 ha) to achieve a broad distribution of sizes.

Présentation : USDA

Page publiée le 23 novembre 2015, mise à jour le 12 novembre 2017