Ken Heck

Ken Heck
Dauphin Island Sea Lab | DISL · University Programs

About

192
Publications
38,287
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16,356
Citations
Citations since 2016
35 Research Items
6946 Citations
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201620172018201920202021202202004006008001,000
201620172018201920202021202202004006008001,000

Publications

Publications (192)
Article
Full-text available
Abstract Biodiversity can enhance the response of ecosystems to disturbance. However, whether diversity can reduce the ecological effect of human‐induced novel and extreme disturbances is unclear. In April 2010, the Deepwater Horizon (DwH) platform exploded, allowing an uncontrolled release of crude oil into the northern Gulf of Mexico. Initial sur...
Article
Full-text available
Halodule wrightii (shoal grass) is a dioecious seagrass with a widespread tropical and subtropical distribution. Like all seagrass species, H. wrightii has the ability to expand asexually through rhizome elongation and to reproduce sexually through seed. To better understand H. wrightii sexual recruitment dynamics in the northern Gulf of Mexico, we...
Article
Full-text available
The importance of habitat factors in designing marine reserves and evaluating their performance over time has been regularly documented. Over three biennial sampling periods, we examined the effects of vegetated coverage and habitat diversity (i.e., patchiness) on fish density, community composition, and species-specific patterns along a gradient o...
Article
While it has been well established that waterbirds can consume substantial amounts of submerged aquatic vegetation (SAV) on their wintering grounds, relatively little is known about their effects on SAV in the northern Gulf of Mexico (nGOM). We measured the impact of wintering American coot (Fulica Americana) foraging on native wild celery (Vallisn...
Article
Estuarine ecosystems are characterized by heterogeneity in species assemblages and habitat complexity, so prey in these systems are often threatened by multiple predators across a mosaic of habitats. When several predator species or conspecifics co-occur, behavioral interactions between them can introduce non-independence to their predator-prey dyn...
Article
Full-text available
The expansion of black mangrove Avicennia germinans into historically smooth cordgrass Spartina alterniflora-dominated marshes with warming temperatures heralds the migration of the marsh-mangrove ecotone northward in the northern Gulf of Mexico. With this shift, A. germinans is expected to outcompete S. alterniflora where it is able to establish,...
Data
Linear decomposition model. Y-axis: dry mass at time t divided by initial dry mass. A. germians: r2 = 0.89; S. alterniflora: r2 = 0.95. (TIF)
Data
Double-exponential decomposition model. Y-axis: dry mass at time t divided by initial dry mass. A. germinans: r2 = 0.90; S. alterniflora: r2 = 0.99. (TIF)
Article
While it has been well established that waterfowl can sometimes control the distribution and abundance of seagrasses, relatively little is known about their effects in the northern Gulf of Mexico (nGOM). Seagrass meadows provide critical habitat for commercially important finfish and shellfish and as winter waters continue to warm, the nGOM will li...
Chapter
Seagrasses are known to provide important habitats for a diversity of fish and fisheries species. Continued research has allowed us to re-evaluate the generalisations, and identify the gaps in our knowledge regarding these habitats, particularly in an Australian context. Seagrasses generally form part of a mosaic with other habitats within a seasca...
Article
The tropically associated black mangrove (Avicennia germinans) is expanding into salt marshes of the northern Gulf of Mexico (nGOM). This species has colonized temperate systems dominated by smooth cordgrass (Spartina alterniflora) in Texas, Louisiana, Florida and, most recently, Mississippi. To date, little is known about the habitat value of blac...
Article
Full-text available
Asian tiger shrimp, Penaeus monodon Fabricius, 1798 are a newly established exotic species on the Atlant ic and Gulf coasts of the United States (US). Their size, estuarine distribution, and diet preference for crustaceans and mollusks in their native range suggest that these shrimp may have significant impacts on a vari ety of species native...
Article
Nearshore coastal ecosystems are among the most productive environments on the planet but are threatened as a result of sea level rise, human development and pollution. These ecosystems often act as a sink for contaminants released into the open ocean as documented during the 2010 Deepwater Horizon oil spill. The geographic extent (1000s of km of p...
Article
Full-text available
The fish Sarpa salpa (L.) is one of the main macroherbivores in the western Mediterranean. Through direct and indirect mechanisms, this herbivore can exert significant control on the structure and functional dynamics of seagrass beds and macroalgae. Past research has suggested nutritional quality of their diet influences S. salpa herbivory, with th...
Article
Full-text available
Phenotypic variability is a valuable adaptive mechanism for seagrass species that exist in a dynamic environment and can lead to significant intraspecific regional distinctions in life history. Research is lacking in studies examining the significance of within-species phenotypic variation in relation to gradients in environmental condition at a la...
Article
Full-text available
We evaluated the impact of shoreline dynamics on fringing vegetation density at mid- and low-marsh elevations at a high-energy site in the northern Gulf of Mexico. Particularly, we selected eight unprotected shoreline stretches (75 m each) at a historically eroding site and measured their inter-annual lateral movement rate using the DSAS method for...
Data
Total density mid marsh. (DOCX)
Data
Live density mid marsh. (DOCX)
Data
Live density low marsh. (DOCX)
Data
Total density low marsh. (DOCX)
Article
Full-text available
Oyster reefs and seagrass beds are being lost worldwide at alarming rates. These habitats provide many services to humankind and, thus, much effort has been dedicated to their restoration. Here, we examine the efficacy of created oyster reefs at enhancing seagrass beds through the amelioration of hydrographic conditions and water quality. We carrie...
Article
Full-text available
Coastal lagoons are ubiquitous along coastlines worldwide. Here, we compare the abundance of epifauna, seagrass-associated macroinvertebrates, and small fish across a gradient of seagrass cover in shallow coastal lagoons of the northern Gulf of Mexico. Two of the lagoons had little or no seagrass cover (0–18.8 %), and four had high cover (83.8–97.5...
Article
Full-text available
Temperatures are rising in most temperate and polar environments, and a well-documented effect of this change is a poleward range shift by a wide variety of terrestrial and aquatic species. In the northern Gulf of Mexico (GOM), an increasing number of tropical species have recently become established among the extant warm-temperate fauna. These inc...
Article
Full-text available
Estuarine shorelines have been degraded since humans arrived in the coastal zone. In recent history, a major cause of habitat degradation has been the armoring of shorelines with vertical walls to protect property from erosive wave energy; however, a lack of practical alternatives that maintain or enhance ecological function has limited the options...
Article
Top-down impacts of avian predators are often overlooked in marine environments despite evidence from other systems that birds significantly impact animal distribution and behavior; instead, birds are typically recognized for the impacts of their nutrient rich guano. This is especially true in shallow seagrass meadows where restoration methods util...
Article
Full-text available
Syntheses of research spanning diverse taxa, ecosystems, timescales, and hierarchies are crucial for understanding the cumulative impacts of the Macondo oil spill in the Gulf of Mexico. Four years after the spill, responses of estuarine fishes to oil pollution have been studied at organismal through population levels, and there is an emerging misma...
Article
Full-text available
Climate-driven changes in biotic interactions can profoundly alter ecological communities, particularly when they impact foundation species. In marine systems, changes in herbivory and the consequent loss of dominant habitat forming species can result in dramatic community phase shifts, such as from coral to macroalgal dominance when tropical fish...
Conference Paper
Large and apparently unprecedented increases in the abundance of juvenile gray (Lutjanus griseus) and lane snapper (L. synagris) within northern Gulf of Mexico (nGOM) seagrasses have been recently documented. Although previously occurring infrequently within the nGOM, their increased abundance coincides with regional warming trends, and may result...
Article
Full-text available
Beach nourishment is becoming an increasingly common method to offset shoreline erosion worldwide. The effects of nourishment and resulting sedimentation on adjacent seagrasses have been previously examined; however, few studies have investigated the effects of beach nourishment on seagrass-associated benthic macrofauna. This is especially true for...
Article
Structural complexity strongly influences the outcome of predator–prey interactions in benthic marine communities affecting both prey concealment and predator hunting efficacy. How habitat structure interacts with species-specific differences in predatory style and antipredatory strategies may therefore be critical in determining higher trophic fun...
Data
Full-text available
Structural complexity strongly influences the outcome of predator–prey interactions in benthic marine communities affecting both prey concealment and predator hunting efficacy. How habitat structure interacts with species-specific differences in predatory style and antipredatory strategies may therefore be critical in determining higher trophic fun...
Article
Full-text available
The loss of salt-marsh habitat is proceeding at an alarming rate worldwide, resulting in the loss of ecosystem function and reduced exchange with adjacent habitats. The immediate result of shoreline erosion is the loss of fringing vegetation, but it is unclear how, and at what temporal scale, intertidal floral zones respond to shoreline loss. Using...
Article
We investigated the interaction between epiphyte-grazer abundance and eutrophication to assess the relative importance of top-down and bottom-up effects in subtropical seagrass meadows. In field experiments using a cageless technique to control amphipod abundance, we measured the effects of grazing and nutrient supply on the growth and productivity...
Article
Full-text available
The emulsification of oil at the Deepwater Horizon (DWH) well head relegated a large proportion of resultant hydrocarbon plumes to the deep sea, facilitated the incorporation of oil droplets into microbial and planktonic food web, and limited the severity of direct, wetland oiling to coastal Louisiana. Nevertheless, many transient fish and inverteb...
Data
Supporting Tables S1–S7. (DOCX)
Article
The incorporation of d(13)C and d(18)O from respired CO2 to tests and whole calcified tissues (WCT) of the sea urchin Lytechinus variegatus was investigated in 120 individuals to elucidate the influence of diet type on the calcification process. Sea urchins were raised during 4 mo in controlled seawater tanks using 3 different diets (d(13)C; d(18)O...
Article
The induction of morphological, physiological and chemical defenses against herbivory is well known in seaweeds, but relatively unstudied in seagrasses. To determine if grazing history affected turtlegrass (Thalassia testudinum) palatability, choice and no choice feeding experiments were conducted with turtlegrass and the variegated sea urchin (Lyt...
Conference Paper
Full-text available
In this study we examine the effects of salinity on the morphology and ion accumulation in leaves and rhizomes of the seagrasses Thalassia testudinum and Halodule wrightii. To this end, shoots were planted in a series of aquaria and exposed for 7 days to 10, 23 (control treatment), 30, 40, 50 and 70 psu. Increasing salinity reduced the number of le...
Presentation
Full-text available
Structural complexity strongly influences the outcome of predator-prey interactions in benthic marine communities affecting both prey concealment and predator hunting efficacy. How habitat structure interacts with species-specific differences in predatory style and antipredatory strategies may therefore be critical in determining higher trophic fun...
Article
Full-text available
Consumer-diet discrimination factors (Delta N-15 and Delta C-13) are often applied without corroboration from laboratory experiments. Deviations in Delta N-15 and Delta C-13 that may occur from different diet types were quantified by raising 120 sea urchins Lytechinus variegatus in laboratory tanks on 3 different diets: seagrass Thalassia testudinu...
Article
Full-text available
The trophic role of the sea urchin Lytechinus variegatus (Lamarck) and the importance of epiphytes as mediators of trophic interactions were evaluated in a Thalassia testudinum meadow, St. Joseph Bay, Florida, in fall 2010. Tethering experiments were deployed within the meadow to assess consumption rates, and food choice experiments, with combinati...
Article
Densities of submerged vegetation and those of associated animals tend to co‐vary. This relationship is often attributed to the positive correlation between the density of vegetation and its protective value against predators. However, two counteracting basic elements underlying this paradigm limit its generality. That is, increasing vegetation den...
Article
Full-text available
We investigated the effects of differing spatial scales of seagrass habitat architecture on the composition and abundance of settling bivalves in a sub-tropical seagrass community. The density of newly settled bivalves was generally greater atThalassia testudinum grass bed edge (<1 m) compared to interior portions of the bed (>10 m). Deviation from...
Data
Results of Repeated-Measures ANOVA on Vegetation Retreat. (DOCX)
Data
Relative Abundance of the Most Abundant Fishes and Mobile Invertebrates. (DOCX)
Data
Results from Wilcoxon Signed-Rank Tests on Single Species or Grouped Taxa. (DOCX)
Data
Results from Multivariate PERMANOVA Tests. (DOCX)
Data
Results from Univariate PERMANOVA Tests. (DOCX)
Article
Full-text available
Shorelines at the interface of marine, estuarine and terrestrial biomes are among the most degraded and threatened habitats in the coastal zone because of their sensitivity to sea level rise, storms and increased human utilization. Previous efforts to protect shorelines have largely involved constructing bulkheads and seawalls which can detrimental...
Data
Summary table for CPUE data (fish kilometer-towed−1) of fishes prior to (2006–2009) and following (2010) the DH disaster. (DOCX)
Data
Distribution of trawl samples among sampling areas (Chandeleur Islands, Gulf Islands, Grand Bay, Florida Bays) and years (2006–2010). (DOCX)
Data
Quantitative description of seagrass habitats sampled throughout the northern Gulf of Mexico during 2006–2010. (DOCX)
Data
Summary table for the management status of the 20 most abundant fishes collected during our survey program. (DOCX)
Data
Summary table of the effects of sampling area and year (context: pre- versus post-spill) on the diversity (S, ES(20), H′, and J′) of trawl samples collected within northern Gulf of Mexico seagrass meadows. (DOCX)
Data
Information used to determine the likelihood of larvae contacting oiled water during the summer of 2010. (DOCX)
Data
Comparisons of community structure between catch data prior to (2006–2009) or immediately following (2010) the Deepwater Horizon disaster (ANOSIM and SIMPER). (DOCX)
Data
Summary table of the effects of sampling area, larval risk and harvest pressure on the change in catch rates of individual species for pre- (2006–2009) and post-spill (2010) data. (DOCX)
Data
Complete CPUE data obtained for 2006–2009 trawl surveys within seagrass meadows of the northern Gulf of Mexico. (XLSX)
Data
Catch rates of all fishes, pooled together, among sampling areas prior to (2006–2009) and following (2010) the Deepwater Horizon disaster. (DOCX)
Data
Catch rates of individual species, among sampling areas prior to (2006–2009) and following (2010) the Deepwater Horizon disaster. Data are presented for the 20 most abundant species. (DOCX)
Data
Catch rates among sampling areas and years for the 20 most abundant species collected during trawl surveys. (DOCX)
Data
Diversity measures for seagrass-associated fish communities within sampling areas affected by the Deepwater Horizon disaster. (DOCX)
Data
Summary table of the effects of sampling area and year (context: pre- versus post-spill) on the catch rates of the 20 most abundant fishes collected during surveys in northern Gulf of Mexico seagrass meadows. (DOCX)
Article
Full-text available
The ecosystem-level impacts of the Deepwater Horizon disaster have been largely unpredictable due to the unique setting and magnitude of this spill. We used a five-year (2006-2010) data set within the oil-affected region to explore acute consequences for early-stage survival of fish species inhabiting seagrass nursery habitat. Although many of thes...
Article
Consumers of seagrasses are increasingly recognized for their ability to shape landscape features and regulate energy flux in coastal ecosystems. To date, however, the nutritional characteristics and morphological features by which herbivores and omnivores make feeding decisions are poorly understood. To elucidate how consumers of marine vascular p...
Article
Full-text available
Eutrophication is a widespread phenomenon that disrupts natural ecosystems around the globe. Despite the general recognition that ecosystems provide many services and benefits to humans, little effort has been made to address how increasing anthropogenic eutrophication affects those services. We conducted a field experiment to determine the effect...
Article
Full-text available
The ability of oysters to remove large quantities of particulates from the water column, thereby potentially improving water quality, has been cited as one of the reasons for oyster reef restoration. However, this ability has not yet been effectively demonstrated in the field. As part of the Alabama Oyster Reef Restoration Project, this study was d...
Article
Full-text available
The indirect, behavioral effects of predation and predator-predator interactions can significantly alter the trophic ecology of many communities. In numerous instances, the strength of these effects may be determined by the ability of prey to identify predation risk through predator-specific cues and respond accordingly to avoid capture. We exposed...
Article
Full-text available
Abstract Global temperatures are rising, and are expected to produce a poleward shift in the distribution of many organisms. We quantified changes in fish assemblages within seagrass meadows of the northern Gulf of Mexico (GOM) between the 1970s and 2006–2007, and observed changes consistent with this forecast. During 2006–2007 we sampled seagrass...