Populations of Acer grandidentatum Nutt. (Bigtooth maple, Aceraceae = Sapindaceae) in central Texas are mostly found in isolated, deep, relatively remote, limestone canyons. Acer grandidentatum is found with a few oth...Populations of Acer grandidentatum Nutt. (Bigtooth maple, Aceraceae = Sapindaceae) in central Texas are mostly found in isolated, deep, relatively remote, limestone canyons. Acer grandidentatum is found with a few other mostly deciduous species. Recruitment of juveniles has been reported to be lacking. One population of A. grandidentatum juveniles was found in a limestone canyon in a State Natural Area in Central Texas. Fifty juveniles were located. Wire enclosures were placed around half of the seedlings with half left in the open. In an adjacent canyon, 50 juvenile seedlings were planted in a similar habitat with adult A. grandidentatum trees nearby. Half were in enclosures and half in the open. Plant survival was followed for four growing seasons until November 2019. At the end of that time when survivals were compared between plants in enclosures and those in the open in both canyon communities, there was a significant difference in survival in both communities (χ2, P < 0.001). Survival in the planted population in enclosures was 92% with 52% in the open. In the natural population in enclosures 68% survived, with 32% survivals in the open. When population extinction was compared, extinction for planted juveniles in enclosures using linear regression was 60.5 yrs and it was 11.9 yrs in the open. For native juveniles, it was 12.6 yrs in enclosures and 5.9 yrs in the open. The cause of most mortalities in the open seemed to be herbivory by white-tailed deer (Odocoleus virginianus).展开更多
文摘Populations of Acer grandidentatum Nutt. (Bigtooth maple, Aceraceae = Sapindaceae) in central Texas are mostly found in isolated, deep, relatively remote, limestone canyons. Acer grandidentatum is found with a few other mostly deciduous species. Recruitment of juveniles has been reported to be lacking. One population of A. grandidentatum juveniles was found in a limestone canyon in a State Natural Area in Central Texas. Fifty juveniles were located. Wire enclosures were placed around half of the seedlings with half left in the open. In an adjacent canyon, 50 juvenile seedlings were planted in a similar habitat with adult A. grandidentatum trees nearby. Half were in enclosures and half in the open. Plant survival was followed for four growing seasons until November 2019. At the end of that time when survivals were compared between plants in enclosures and those in the open in both canyon communities, there was a significant difference in survival in both communities (χ2, P < 0.001). Survival in the planted population in enclosures was 92% with 52% in the open. In the natural population in enclosures 68% survived, with 32% survivals in the open. When population extinction was compared, extinction for planted juveniles in enclosures using linear regression was 60.5 yrs and it was 11.9 yrs in the open. For native juveniles, it was 12.6 yrs in enclosures and 5.9 yrs in the open. The cause of most mortalities in the open seemed to be herbivory by white-tailed deer (Odocoleus virginianus).
