Tuesday, August 7, 2007 - 1:50 PM

COS 56-2: Nurse plants for increasing Abies religiosa survival and growth: Consequences for Monarch Butterfly (Dannaus plexipus) habitat restoration

Arnulfo Blanco-García and Roberto Lindig-Cisneros. National University (Mexico) or Universidad Nacional Autonoma de Mexico

Abies religiosa (sacred fir) is the most common species of this genus in Mexico and is restricted to high elevation locations (from 2,400 to 3,500 meters above sea level). In 1970 Abies forests occupied 0.16% of the country land area nowadays cover only 0.1%. Restoration of Abies forests is a conservation priority.

We evaluated the effect of sowing a native legume (Lupinus elegans) on survival and growth of Abies trees in an agricultural abandoned field being restored. We planted 144 seedlings, 22 months of age in patches with and without sowed lupines in july 2004. After two and half years, overall survival was 26 %, (33 % in patches with legumes and 21% in control patches). Survival decreased from 75 % to 39 % between April and June of 2005. The highest mortality was recorded in the peak of the dry season when lupine canopy was not fully developed. Two and a half years after planting trees under legumes are taller (25 ± 4 cm) than in control plots (13 ± 6 cm). Soil nitrogen concentrations increased in a two year period from 43 kg/ha to 59 Kg/ha in legume patches and 56 Kg/ha in control patches.

            In arrival monarch butterflies (Dannaus plexipus) areas, current survival rates of Abies are 10 % or lower.  Our results suggest that use of Lupinus elegans as a nurse and nitrogen fixing plant is an efficient way of increasing Abies religiosa survival and growth under restoration conditions.