Recovery of an imperiled plant species may require augmentation of existing populations or creation of new ones.Hundreds of such projects have been conducted over the last few decades,but there is a bias in the litera...Recovery of an imperiled plant species may require augmentation of existing populations or creation of new ones.Hundreds of such projects have been conducted over the last few decades,but there is a bias in the literature favoring successes over failures.In this paper,we evaluate a series of introductions that experimentally manipulated microhabitat and fire in an adaptive introduction framework.Between 2002 and 2012,we(and our collaborators) carried out ten introductions and augmentations of Florida ziziphus Pseudoziziphus(Condalia,Ziziphus) celata,a clonal shrub limited to very small populations and narrowly endemic to pyrogenic central Florida sandhills.Six of the introductions were designed as experiments to test hypotheses about how demographic performance was affected by microhabitat,fire,and propagule type.Introduced transplants had high survival(<90%annually),inconsistent growth,and little transition to reproduction,while introduced seeds had low germination and survival.Transplants were more efficient than seeds as translocation propagules.Shaded(vs.open) sites supported generally higher transplant and seedling survival and seed germination percentages,but growth responses varied among experiments.Supplemental irrigation increased transplant survival and seed germination,but otherwise seedling and plant survival and growth were not significantly affected.Contrary to expectations based on wild populations,introduced propagules have not been more successful in unshaded sites,suggesting that Florida ziziphus has broader microhabitat preferences than hypothesized.Compared to wild plants,introduced plants had similar survival and responses to fire,slower growth,and more delayed flowering.Introduced plants had no clonal spread.While no introduced population has demonstrated a capacity for long-term viability,one augmented population has flowered and produced viable fruits.Given that Florida ziziphus genets are long-lived,low levels of sexual reproduction may be adequate for the establishment of viable populati展开更多
Semen characteristics of naturally fertile pairs and their correlation with fertility of eggs in Florida sandhill crane (Grus canadensis pratensis) were examined. Six pairs were used in this experiment, and all of the...Semen characteristics of naturally fertile pairs and their correlation with fertility of eggs in Florida sandhill crane (Grus canadensis pratensis) were examined. Six pairs were used in this experiment, and all of them that had bred before were housed in open individual pens. These pairs were isolated physically each other but not visually and audibly. Semen was collected twice (Tuesday morning and Friday afternoon) from February 26 to June 4, 1993. The standard methods at Patuxent Wildlife Research Center were used collecting and evaluating the semen and spermatozoa. and incubating the eggs. There were statistically individual variations (p<0.05) about successful collecting attempts, semen volume, semen concentration, spermatozoon’s motility,spermatozoon’s number per collection, live spermatozoon’s number, male’s response to semen collection, and morphology of spermatozoa except the giant cell. There was a significantly (p<0.05, correlation coefficient was (0.73 or (1 .00) negative correlation between fertility of eggs and the multiple value of semen (sperm) characteristics of naturally fertile pairs in Florida sandhill crane.展开更多
基金funding and support from the Rare Plant Conservation program of the Florida Forestry Service,managed by Dennis Hardin and Mike Jenkinsthe National Science Foundation(DEB98-15370,DEB02-33899,DEB08-12717,DEB-1347843)+1 种基金the US Fish and Wildlife Service,and from Archbold Biological Stationsupport of David Bender(US Fish and Wildlife Service)
文摘Recovery of an imperiled plant species may require augmentation of existing populations or creation of new ones.Hundreds of such projects have been conducted over the last few decades,but there is a bias in the literature favoring successes over failures.In this paper,we evaluate a series of introductions that experimentally manipulated microhabitat and fire in an adaptive introduction framework.Between 2002 and 2012,we(and our collaborators) carried out ten introductions and augmentations of Florida ziziphus Pseudoziziphus(Condalia,Ziziphus) celata,a clonal shrub limited to very small populations and narrowly endemic to pyrogenic central Florida sandhills.Six of the introductions were designed as experiments to test hypotheses about how demographic performance was affected by microhabitat,fire,and propagule type.Introduced transplants had high survival(<90%annually),inconsistent growth,and little transition to reproduction,while introduced seeds had low germination and survival.Transplants were more efficient than seeds as translocation propagules.Shaded(vs.open) sites supported generally higher transplant and seedling survival and seed germination percentages,but growth responses varied among experiments.Supplemental irrigation increased transplant survival and seed germination,but otherwise seedling and plant survival and growth were not significantly affected.Contrary to expectations based on wild populations,introduced propagules have not been more successful in unshaded sites,suggesting that Florida ziziphus has broader microhabitat preferences than hypothesized.Compared to wild plants,introduced plants had similar survival and responses to fire,slower growth,and more delayed flowering.Introduced plants had no clonal spread.While no introduced population has demonstrated a capacity for long-term viability,one augmented population has flowered and produced viable fruits.Given that Florida ziziphus genets are long-lived,low levels of sexual reproduction may be adequate for the establishment of viable populati
文摘Semen characteristics of naturally fertile pairs and their correlation with fertility of eggs in Florida sandhill crane (Grus canadensis pratensis) were examined. Six pairs were used in this experiment, and all of them that had bred before were housed in open individual pens. These pairs were isolated physically each other but not visually and audibly. Semen was collected twice (Tuesday morning and Friday afternoon) from February 26 to June 4, 1993. The standard methods at Patuxent Wildlife Research Center were used collecting and evaluating the semen and spermatozoa. and incubating the eggs. There were statistically individual variations (p<0.05) about successful collecting attempts, semen volume, semen concentration, spermatozoon’s motility,spermatozoon’s number per collection, live spermatozoon’s number, male’s response to semen collection, and morphology of spermatozoa except the giant cell. There was a significantly (p<0.05, correlation coefficient was (0.73 or (1 .00) negative correlation between fertility of eggs and the multiple value of semen (sperm) characteristics of naturally fertile pairs in Florida sandhill crane.
