Sirenians (manatees Trichechus spp. and the dugong Dugong dugon) are large-bodied and almost excl... more Sirenians (manatees Trichechus spp. and the dugong Dugong dugon) are large-bodied and almost exclusively herbivorous aquatic mammals occurring in coastal and freshwater habitats of most tropical and subtropical regions. Although sirenian ecology, habitat use, and abundance have been investigated across their range, little is known about the roles and impacts of these megaherbivores outside of the trophic relationships of 2 relatively well-studied species (T. manatus, D. dugon). This knowledge gap limits our understanding of how sirenians affect communities and ecosystem dynamics. We review the literature on the ecological roles and importance of sirenians in aquatic ecosystems, including the extinct Steller’s sea cow Hydrodamalis gigas. Our review reveals that sirenian herbivory and disturbance can markedly affect species biomass, productivity, and composition in macrophyte communities, thereby indirectly influencing other community members (e.g. invertebrates) and carbon storage in...
The red lionfish (Pterois volitans) is an invasive predatory marine fish that has rapidly expande... more The red lionfish (Pterois volitans) is an invasive predatory marine fish that has rapidly expanded its presence in the Western Hemisphere. We collected 214 invasive red lionfish samples from nine countries and territories, including seven unpublished locations. To more comprehensively evaluate connectivity, we compiled our d-loop sequence data with 846 published sequences, resulting in 1,060 samples from 14 locations. We found low nucleotide diversity (π = 0.003) and moderate haplotype diversity (h = 0.59). Using haplotype population pairwise Φ ST tests, we analyzed possible phylogeographic breaks that were previously proposed based on other reef organisms. We found support for the Bahamas/Turks/Caicos versus Caribbean break (Φ ST = 0.12) but not for the Northwestern Caribbean, Eastern Caribbean, or US East Coast versus Bahamas breaks. The Northern Region had higher variation and more haplotypes, supporting introductions of at least five haplotypes to the region. Our wide-ranging sa...
Journal of the Marine Biological Association of the United Kingdom
Belize contains important habitat for Antillean manatees (Trichechus manatus manatus) and provide... more Belize contains important habitat for Antillean manatees (Trichechus manatus manatus) and provides refuge for the highest known population density of this subspecies. As these animals face impending threats, knowledge of their dietary habits can be used to interpret resource utilization. The contents of 13 mouth, six digestive tract (stomach, duodenum and colon) and 124 faecal samples were microscopically examined using a modified point technique detection protocol to identify key plant species consumed by manatees at two important aggregation sites in Belize: Southern Lagoon and the Drowned Cayes. Overall, 15 different items were identified in samples from manatees in Belize. Five species of seagrasses (Halodule wrightii, Thalassia testudinum, Ruppia maritima, Syringodium filiforme and Halophila sp.) made up the highest percentage of items. The red mangrove (Rhizophora mangle) was also identified as an important food item. Algae (Ulva sp., Chara sp., Lyngbya sp.) and invertebrates ...
West Indian manatees (Trichechus manatus L.) are opportunistic, herbivorous aquatic mammals that ... more West Indian manatees (Trichechus manatus L.) are opportunistic, herbivorous aquatic mammals that occupy the warm, shallow coastal waters throughout the southeastern United States. Manatees are known to feed on large quantities of diverse plant types. Presently within the state of Florida, manatees are an endangered species facing environmental and anthropogenic threats. Several different organizations work to rescue and rehabilitate these animals for an eventual return to the wild. Also within Florida, invasive aquatic plants are becoming increasingly problematic, creating both negative economic and environmental impacts. Each year, efforts are made to control these exotic plant species through several different methods. However, physical, mechanical, chemical and biological means to contain nonindigenous plants each have their drawbacks. There is a need for a natural, integrated approach to invasive aquatic plant management. The opportunity for manatees to control exotic plant species within the Florida ecosystem exists, but is improbable because of inadequate population densities. This study builds on this potential examining the use of manatees held in captivity as a tool for management by utilizing the physical collection of targeted nonindigenous plants to supplement the diet of rehabilitated manatees. Provisions are augmented with nutrients that manatees may not obtain from other sources typically found in captive diets. Early introduction of natural plants may allow for an easier transition to normal feeding patterns upon release and may condition animals to continue consumption of exotic plants in the wild. Each step has the potential to contribute to the reduction of invasive aquatic plants in Florida, and presents a cost-effective feeding alternative for manatee rehabilitation facilities. This method promotes a native Florida species as a natural solution to the problem.
Sirenians (manatees Trichechus spp. and the dugong Dugong dugon) are large-bodied and almost excl... more Sirenians (manatees Trichechus spp. and the dugong Dugong dugon) are large-bodied and almost exclusively herbivorous aquatic mammals occurring in coastal and freshwater habitats of most tropical and subtropical regions. Although sirenian ecology, habitat use, and abundance have been investigated across their range, little is known about the roles and impacts of these megaherbivores outside of the trophic relationships of 2 relatively well-studied species (T. manatus, D. dugon). This knowledge gap limits our understanding of how sirenians affect communities and ecosystem dynamics. We review the literature on the ecological roles and importance of sirenians in aquatic ecosystems, including the extinct Steller’s sea cow Hydrodamalis gigas. Our review reveals that sirenian herbivory and disturbance can markedly affect species biomass, productivity, and composition in macrophyte communities, thereby indirectly influencing other community members (e.g. invertebrates) and carbon storage in...
The red lionfish (Pterois volitans) is an invasive predatory marine fish that has rapidly expande... more The red lionfish (Pterois volitans) is an invasive predatory marine fish that has rapidly expanded its presence in the Western Hemisphere. We collected 214 invasive red lionfish samples from nine countries and territories, including seven unpublished locations. To more comprehensively evaluate connectivity, we compiled our d-loop sequence data with 846 published sequences, resulting in 1,060 samples from 14 locations. We found low nucleotide diversity (π = 0.003) and moderate haplotype diversity (h = 0.59). Using haplotype population pairwise Φ ST tests, we analyzed possible phylogeographic breaks that were previously proposed based on other reef organisms. We found support for the Bahamas/Turks/Caicos versus Caribbean break (Φ ST = 0.12) but not for the Northwestern Caribbean, Eastern Caribbean, or US East Coast versus Bahamas breaks. The Northern Region had higher variation and more haplotypes, supporting introductions of at least five haplotypes to the region. Our wide-ranging sa...
Journal of the Marine Biological Association of the United Kingdom
Belize contains important habitat for Antillean manatees (Trichechus manatus manatus) and provide... more Belize contains important habitat for Antillean manatees (Trichechus manatus manatus) and provides refuge for the highest known population density of this subspecies. As these animals face impending threats, knowledge of their dietary habits can be used to interpret resource utilization. The contents of 13 mouth, six digestive tract (stomach, duodenum and colon) and 124 faecal samples were microscopically examined using a modified point technique detection protocol to identify key plant species consumed by manatees at two important aggregation sites in Belize: Southern Lagoon and the Drowned Cayes. Overall, 15 different items were identified in samples from manatees in Belize. Five species of seagrasses (Halodule wrightii, Thalassia testudinum, Ruppia maritima, Syringodium filiforme and Halophila sp.) made up the highest percentage of items. The red mangrove (Rhizophora mangle) was also identified as an important food item. Algae (Ulva sp., Chara sp., Lyngbya sp.) and invertebrates ...
West Indian manatees (Trichechus manatus L.) are opportunistic, herbivorous aquatic mammals that ... more West Indian manatees (Trichechus manatus L.) are opportunistic, herbivorous aquatic mammals that occupy the warm, shallow coastal waters throughout the southeastern United States. Manatees are known to feed on large quantities of diverse plant types. Presently within the state of Florida, manatees are an endangered species facing environmental and anthropogenic threats. Several different organizations work to rescue and rehabilitate these animals for an eventual return to the wild. Also within Florida, invasive aquatic plants are becoming increasingly problematic, creating both negative economic and environmental impacts. Each year, efforts are made to control these exotic plant species through several different methods. However, physical, mechanical, chemical and biological means to contain nonindigenous plants each have their drawbacks. There is a need for a natural, integrated approach to invasive aquatic plant management. The opportunity for manatees to control exotic plant species within the Florida ecosystem exists, but is improbable because of inadequate population densities. This study builds on this potential examining the use of manatees held in captivity as a tool for management by utilizing the physical collection of targeted nonindigenous plants to supplement the diet of rehabilitated manatees. Provisions are augmented with nutrients that manatees may not obtain from other sources typically found in captive diets. Early introduction of natural plants may allow for an easier transition to normal feeding patterns upon release and may condition animals to continue consumption of exotic plants in the wild. Each step has the potential to contribute to the reduction of invasive aquatic plants in Florida, and presents a cost-effective feeding alternative for manatee rehabilitation facilities. This method promotes a native Florida species as a natural solution to the problem.
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Papers by Aarin-Conrad Allen