Characterizing Manatee habitat use and seagrass grazing in Florida and Puerto Rico: implications for conservation and management

1999 ◽  
Vol 5 (4) ◽  
pp. 289 ◽  
Author(s):  
Lynn W. Lefebvre ◽  
James P. Reid ◽  
W. Judson Kenworthy ◽  
James A. Powell
Keyword(s):  
Puerto Rico ◽  
Root Biomass ◽  
Atlantic Coast ◽  
Indian River Lagoon ◽  
Shoot Biomass ◽  
Feeding Strategies ◽  
Short Shoot ◽  
Tropical Regions ◽  
Seagrass Community ◽  
Indian River

The Indian River Lagoon on the Atlantic coast of Florida, USA, and the east coast of Puerto Rico provide contrasting environments in which the endangered West Indian Manatee Trichechus manatus experiences different thermal regimes and seagrass communities. We compare Manatee feeding behaviour in these two regions, examine the ecological effects of Manatee grazing on a seagrass community in the Indian River Lagoon, describe the utility of aerial surveys, radio tracking, and seagrass mapping to study Manatee feeding patterns, and develop hypotheses on sirenian feeding strategies in temperate and tropical seagrass communities. In both the Indian River Lagoon and Puerto Rico, Manatees were typically observed grazing in water depths = 2.0 m and more frequently on the most abundant seagrasses present in the community: Halodule wrightii in the Indian River Lagoon and Thalassia testudinum in eastern Puerto Rico. Where both H. wrightii and Syringodium filiforme were consumed in the Indian River Lagoon, Manatees tended to remove more S. filiforme than H. wrightii rhizome + root biomass. Even though 80 to 95% of the short-shoot biomass and 50 to 67% of the rhizome + root biomass were removed, grazed patches of H. wrightii and S. filiforme recovered significantly between February and August. H. wrightii may be both more resistant and resilient than S. filiforme to the impacts of Manatee grazing. Despite the significantly greater abundance of T. testudinum in Puerto Rico, Manatees exhibited selective feeding by returning to specific sites with abundant H. wrightii. They also appeared to feed selectively on T. testudinum shoots associated with clumps of the calcareous alga Halimeda opuntia. We hypothesize that Florida Manatees are less specialized seagrass grazers than Manatees in tropical regions like Puerto Rico. Continued research on Manatee grazing ecology in temperate to tropical seagrass communities will enable better protection and management of these vital and unique marine resources.

scholarly journals Growth Responses of Boreal Scots Pine, Norway Spruce and Silver Birch Seedlings to Simulated Climate Warming over Three Growing Seasons in a Controlled Field Experiment

Forests ◽  
2020 ◽  
Vol 11 (9) ◽  
pp. 943
Author(s):  
Katri Nissinen ◽  
Virpi Virjamo ◽  
Antti Kilpeläinen ◽  
Veli-Pekka Ikonen ◽  
Laura Pikkarainen ◽  
...  
Keyword(s):  
Norway Spruce ◽  
Scots Pine ◽  
Root Biomass ◽  
Growing Season ◽  
Silver Birch ◽  
Shoot Biomass ◽  
Growth Responses ◽  
Growing Seasons ◽  
Simulated Climate ◽  
Shoot And Root Biomass

We studied the growth responses of boreal Scots pine (Pinus sylvestris L.), Norway spruce (Picea abies L. Karst.) and silver birch (Betula pendula Roth) seedlings to simulated climate warming of an average of 1.3 °C over the growing season in a controlled field experiment in central Finland. We had six replicate plots for elevated and ambient temperature for each tree species. The warming treatment lasted for the conifers for three growing seasons and for the birch two growing seasons. We measured the height and diameter growth of all the seedlings weekly during the growing season. The shoot and root biomass and their ratios were measured annually in one-third of seedlings harvested from each plot in autumn. After two growing seasons, the height, diameter and shoot biomass were 45%, 19% and 41% larger in silver birch seedlings under the warming treatment, but the root biomass was clearly less affected. After three growing seasons, the height, diameter, shoot and root biomass were under a warming treatment 39, 47, 189 and 113% greater in Scots pine, but the root:shoot ratio 29% lower, respectively. The corresponding responses of Norway spruce to warming were clearly smaller (e.g., shoot biomass 46% higher under a warming treatment). As a comparison, the relative response of height growth in silver birch was after two growing seasons equal to that measured in Scots pine after three growing seasons. Based on our findings, especially silver birch seedlings, but also Scots pine seedlings benefitted from warming, which should be taken into account in forest regeneration in the future.

Dynamics of microcystins and saxitoxin in the Indian River Lagoon, Florida

Harmful Algae ◽  
2021 ◽  
Vol 103 ◽  
pp. 102012
Author(s):  
Abdiel E. Laureano-Rosario ◽  
Malcolm McFarland ◽  
David J. Bradshaw ◽  
Jackie Metz ◽  
Rachel A. Brewton ◽  
...  
Keyword(s):  
Indian River Lagoon ◽  
Indian River

scholarly journals Bloom dynamics and chemical defenses of benthic cyanobacteria in the Indian River Lagoon, Florida

Harmful Algae ◽  
2017 ◽  
Vol 69 ◽  
pp. 75-82 ◽  
Author(s):  
Jennifer M. Sneed ◽  
Theresa Meickle ◽  
Niclas Engene ◽  
Sherry Reed ◽  
Sarath Gunasekera ◽  
...  
Keyword(s):  
Indian River Lagoon ◽  
Chemical Defenses ◽  
Benthic Cyanobacteria ◽  
Indian River

scholarly journals Bivalve Feeding on the Brown Tide Aureoumbra lagunensis in a Shallow Coastal Environment

2021 ◽  
Vol 8 ◽  
Author(s):  
Eve Galimany ◽  
Jessica Lunt ◽  
Christopher J. Freeman ◽  
I. Segura-García ◽  
M. Mossop ◽  
...  
Keyword(s):  
Clearance Rate ◽  
Indian River Lagoon ◽  
Brown Tide ◽  
Bivalve Species ◽  
Clearance Rates ◽  
Interspecific Differences ◽  
Brown Tides ◽  
Indian River ◽  
Aureoumbra Lagunensis ◽  
Fish And Shellfish

Brown tides formed by Aureoumbra lagunensis decrease light penetration in the water column and are often followed by hypoxic events that result in the loss of fish and shellfish. To understand the ability of bivalve filter feeders to control and prevent A. lagunensis blooms, we exposed eastern oysters (Crassostrea virginica), hooked mussels (Ischadium recurvum), and hard clams (Mercenaria mercenaria) to a naturally co-occurring brown tide in the Indian River Lagoon (IRL), Florida, United States. Bivalves were exposed in the laboratory to multiple concentrations (104 to 106 cells mL–1) of isotopically labeled (13C and 15N) A. lagunensis cells. The standard clearance rate (herein clearance rate) of each bivalve species was calculated using flow cytometry to quantify A. lagunensis cell removal. The highest clearance rates were at 104 cells mL–1, but values varied across bivalve species (2.16 ± 0.30, 3.03 ± 0.58, and 0.41 ± 0.12 L h–1 for C. virginica, I. recurvum, and M. mercenaria, respectively). Although clearance rates decreased with increasing bloom concentrations, bivalves were still consuming algal cells at all concentrations and were retaining and assimilating more cells at the highest concentrations, as revealed by δ13C and δ15N values. We highlight interspecific differences among bivalve species in the removal of A. lagunensis, supporting the importance of healthy and diverse filter feeding communities in estuaries, especially as threats of brown tides and other HABs are increasing in the Anthropocene.

scholarly journals Early root development of Eucalyptus pellita F. Muell. seedlings from seed and stem cutting at nursery stage

2020 ◽  
Author(s):  
Affendy Hassan ◽  
Parveena Balachandran ◽  
Khairiyyah Razanah Khamis
Keyword(s):  
Root Development ◽  
Root Length ◽  
Root Biomass ◽  
Nitrogen Concentration ◽  
Stem Cutting ◽  
Shoot Biomass ◽  
Forest Plantation ◽  
Plant Materials ◽  
Eucalyptus Pellita ◽  
Root Intensity

Abstract BackgroundEucalyptus is among the important fast-growing species, and is typically managed on short rotation to sustain the production of timber, pulpwood, charcoal, and fire-wood. Macro-propagation using cutting for larger multiplying seedlings is cheaper and efficient instead of clonal seeds for uniform plant material seedling production. However, information on root growth of Eucalyptus pellita at early development from seed and stem cutting of E. pellita seedlings is still lacking. This is probably due to the difficulty in investigation belowground, and also due to methodological problems. With such information, it is useful for forest plantation company management in enhancing the understanding on strategies to optimize yield production with the appropriate agronomic or silvicultural approach in the field planting. Therefore, the objectives of this study were; to compare the root development of two different propagation seedlings of E. pellita; and to study the effect of various nitrogen concentration levels on two types of propagation of E. pellita seedlings. ResultsThe study was conducted using E. pellita seedlings from two types of propagation, namely, seed and stem cuttings, along with three different nitrogen concentrations (0, 50, and 200 kg N ha-1). Shoot biomass, root intensity (RI), total root intensity (TRI), root biomass, root length density (RLD), and specific root length (SRL) were recorded. Dried shoot biomass, RLD and SRL of E. pellita seedlings using stem cutting were significantly higher (P<0.05) compared to seed. Whereas, there were no significant differences (P>0.05) for root biomass, TRI and RI between the propagation types of E. pellita seedlings. Conclusions:E. pellita seedlings from stem cutting was greater in terms of root distribution compared to propagation by seeds at the nursery stage, and 50 kg N ha-1 was the optimal nitrogen concentration level from the considered levels to be applied to the E. pellita seedlings. The present study therefore provides more information and understanding on E. pellita for forest plantation companies in producing plant materials using stem cutting in a cost-effective and efficient manner. This would help the forest plantation companies in planning appropriate agronomic management in the future.

Invasive Syzygium jambos trees in Puerto Rico: no refuge from guava rust

2017 ◽  
Vol 33 (3) ◽  
pp. 205-212 ◽  
Author(s):  
Erin Burman ◽  
James D. Ackerman ◽  
Raymond L. Tremblay
Keyword(s):  
Puerto Rico ◽  
Species Distribution Modelling ◽  
Negative Consequences ◽  
Tropical Regions ◽  
Mountainous Regions ◽  
Syzygium Jambos ◽  
Guava Rust ◽  
Invasive Tree ◽  
High Precipitation ◽  
Austropuccinia Psidii

Abstract:Biological invasions can have negative consequences for resident biota, particularly when disease-causing organisms are involved. Austropuccinia psidii, or guava rust, has rapidly spread through the tropics affecting both native and non-native Myrtaceae. In Puerto Rico, the rust has become common on Syzygium jambos, an invasive tree native to South-East Asia. What are the drivers of infection, and do refugia exist across a heterogeneous landscape? We address these questions using species distribution modelling and beta regressions. The realized and potential distribution of Syzygium jambos is extensive. The model produced an AUC of 0.88, with land-use categories and precipitation accounting for 61.1% of the variation. Predictability of S. jambos is highest in disturbed habitats, especially in mountainous regions with high precipitation. All 101 trees surveyed and measured across Puerto Rico showed signs of infection to varying extents. Infection severity was consistently associated with annual mean temperature in all top beta regression models, but was also commonly associated with tree size and precipitation variables. We found no safe sites for S. jambos. Many trees were extremely unhealthy and some were dead, suggesting that S. jambos may soon become extinct on the island or reduced to persistent stump sprouts. Native vegetation may benefit from the local demise of S. jambos. While the rust has not jumped to native Myrtaceae, vigilance is required, as host-shifts have occurred in other tropical regions.

The Living Dock: A Study of Benthic Recruitment to Oyster Substrates Affixed to a Dock in the Indian River Lagoon

2018 ◽  
Vol 52 (4) ◽  
pp. 7-18
Author(s):  
Robert J. Weaver ◽  
Kelli Hunsucker ◽  
Holly Sweat ◽  
Kody Lieberman ◽  
Abby Meyers ◽  
...  
Keyword(s):  
Citizen Science ◽  
Indian River Lagoon ◽  
Pilot Project ◽  
Percent Cover ◽  
Benthic Organisms ◽  
Science Project ◽  
Time Period ◽  
Indian River ◽  
Local Water ◽  
Citizen Science Project

AbstractBenthic filter feeding organisms have the potential to improve local water quality by filtering microalgae and particulate matter out of the water column. A pilot project was conducted to test the concept of creating a Living Dock by growing these filter feeders at a dock in the Indian River Lagoon. Two different methods (mats and bags) were tested for their ability to recruit benthic organisms, as well as the efficacy of these methods for use as a long-term citizen science project. Eighteen oyster mats were wrapped around dock pilings, and 18 oyster bags were suspended between pilings of the same dock. After 1 year of immersion, healthy populations of barnacles, sponges, algae, bryozoans, mussels, and tunicates were found growing on both the bags and the mats. During that same time period, live oysters were also found growing on both mats and bags, with a maximum of 73 live oysters in one bag. Although the total percent cover of organisms settling on the shells did not differ between the mats or the bags, there was significantly greater organismal diversity in the bag treatment compared to the mat treatment. Bags were a more effective recruiter of benthic organisms, but longevity was an issue, with bags becoming heavily fouled and often breaking loose from the dock over time. It was noted that the mats with the higher shell densities saw greater recruitment and had greater diversity. Although the bags proved to be a better alternative than mats for the recruitment and growth of benthic organisms, they are not sustainable for use as a citizen science project. Future efforts should consider constructing mats with high-density shell counts, as the mats have more durability and are better suited for citizen scientists.

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