Giant reed is one of the most widespread invasive species in riparian habitats in California and other coastal states of the United States. This species is thought to spread primarily asexually by flood dispersal of stem and rhizome pieces; viable seeds have not been found in the United States. Research was conducted to quantify genetic variation in giant reed along the Santa Ana River in California and to investigate the pattern of distribution of variation along this watershed. Populations at least 3.2 km apart were collected along the length of the Santa Ana River from the headwaters to the Pacific Ocean. One additional population from a different watershed was collected to serve as an out-group. Genetic analyses were conducted using both starch gel electrophoresis for isozyme analysis and random amplified polymorphic DNA (RAPD) analysis. Both isozyme and RAPD analyses revealed levels of genetic diversity comparable with those in the literature for clonal species, suggesting that asexual reproduction is the primary means of spread of giant reed. Most phenotypes were spread along the Santa Ana River, which is expected if water is the primary means of spread of vegetative propagules. Among the unique phenotypes found, two isozyme phenotypes and one RAPD phenotype were dominant and were found spread along the river, which may indicate greater fitness or competitive superiority to the other phenotypes that were less common. The dominant phenotypes were also found in the out-group population, possibly because of spread by humans. Because spread occurs mainly asexually, management efforts should focus on preventing establishment and spread of vegetative propagules. A moderate level of genetic diversity also suggests that biological control of this weed could be successful.
The Giant Nuthatch Sitta magna is restricted to southwestern China, eastern Myanmar, and northern Thailand. Although globally endangered, most aspects of its ecology remain as yet unquantified. To assess its habitat associations and population size, we conducted point counts with playback at 42 sample points across 12 discrete historical and potential localities within its Thai range during October to November 2015. Eleven habitat variables were measured, including three site-level vegetation variables and eight landscape variables were assessed, using geographic information system land cover maps. Nmixture models were applied to estimate density and extrapolate the size of the population. The Giant Nuthatch was found at four localities (12 of the 42 sample points) at elevations between 1,192 m and 1,738 m. It was not detected at four historical Giant Nuthatch localities in protected areas. Abundance increased with increasing elevation, increasing proportion of evergreen forest, and greater distance from villages. We estimated that the Thai population of Giant Nuthatch was approximately 964 individuals based on an average density of 1.96 individuals/km 2 in approximately 491.8 km 2 of appropriate forest habitat at 1,192 m to 1,951 m elevation. This may be an overestimate because available forest cover maps and images do not distinguish between the characteristic, patchily distributed, lower montane open pine-oak forest association used by Giant Nuthatch and denser, closed-canopy forest. Although Thailand's Giant Nuthatch population may be better protected than those in adjoining countries, we suggest that it remains threatened by forest fragmentation and habitat degradation throughout its range. Further comprehensive research is needed to assess the status of the remaining global population and the reasons for its scarcity.
The illegal wildlife trade, especially of live animals, is a major threat to slow lorises. Large numbers of confiscated slow lorises are sent to rescue facilities. We aimed to describe the occurrence and types of abnormal repetitive behaviours (ARBs) in 36 confiscated Bengal slow lorises (Nycticebus bengalensis), and examined factors influencing the occurrence of ARBs. We recorded behaviours of the slow lorises using instantaneous scans every 5 min from 19: 00 to 06: 00 h, and observed 6 types of ARBs in 14 (38.9%) individuals. Each individual exhibited 1 type of ARB. The most prevalent ARBs were pacing, rocking and up-down movement, and represented 29.9 ± 13.6% of the activity budget. Sex did not significantly influence the occurrence of ARB. Animals who had been at the centre for longer had a greater tendency to exhibit ARBs, but this was not statistically significant. We suggest that housing slow lorises in large semi-natural enclosures with conspecifics may reduce ARBs. Other factors potentially influencing ARBs, such as cage size, should be further investigated.
The endangered vermilion darter (Etheostoma chermocki) is endemic to the Black Warrior River system in the Mobile Basin in Alabama. Restoration and conservation of this species require an understanding of its population genetic structure, which can be characterized using microsatellite DNA. Nine microsatellite loci were developed; eight loci were polymorphic. Although observed heterozygosity was lower than expected heterozygosity in most polymorphic loci, only one locus showed significant deviation from Hardy–Weinberg equilibrium. These nine markers were tested in an additional 24 species of Etheostoma and appear to have sufficient allelic variation to be useful in studies of population genetic structure.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.