Delbert 'Lee' Smee

• Ph.D.
• Professor (Associate) at Texas A&M University – Corpus Christi

Intense disturbances such as hurricanes may drastically affect ecosystems, producing both acute and long-term changes along coastlines. By disrupting human activities (e.g., fishing), hurricanes can provide an opportunity to quantify the effects of these activities on coastal ecosystems. We performed predator-exclusion experiments on oyster reefs i...

On 10 October 2018, Hurricane Michael made landfall along the Florida panhandle as a category 5 storm, with maximum sustained winds of 259 km h−1 and storm surge of 4.3 m. To assess impacts on seagrass meadows and nekton communities, we sampled seagrass beds in three estuaries along a gradient of storm intensity: one proximate to the hurricane trac...

Predator-prey interactions are a key feature of ecosystems and often chemically mediated, whereby individuals detect molecules in their environment that inform whether they should attack or defend. These molecules are largely unidentified, and their discovery is important for determining their ecological role in complex trophic systems. Homarine an...

Climate change is altering species’ range limits and transforming ecosystems. For example, warming temperatures are leading to the range expansion of tropical, cold-sensitive species at the expense of their cold-tolerant counterparts. In some temperate and subtropical coastal wetlands, warming winters are enabling mangrove forest encroachment into...

The capacity of an apex predator to produce nonconsumptive effects (NCEs) in multiple prey trophic levels can create considerable complexity in nonconsumptive cascading interactions, but these effects are poorly studied. We examined such effects in a model food web where the apex predator (blue crabs) releases chemical cues in urine that affect bot...

Hydrodynamic stress shapes the flora and fauna that exist in wave-swept environments, alters species interactions, and can become the primary community structuring agent. Yet, hydrodynamics can be difficult to quantify because instrumentation is expensive, some methods are unreliable, and accurately measuring spatial and temporal differences can be...

Many prey species can adjust morphology to reduce predation risk in response to predator cues. Enhancing prey defenses using predator cues may improve survival of cultivated species and enhance species restoration efforts, but assessment of such benefits at industrially relevant scales is needed. We examined how raising a model foundation species,...

Drift macroalgae, often associated with seagrass habitats, may provide resources and habitat to seagrass associated fauna, increasing faunal abundance and diversity. Yet, excessive amounts of drift macroalgae can be harmful, reducing the abundance of both aquatic angiosperms and animals by causing localized hypoxia. To ascertain the effects of drif...

Drift macroalgae, often found in clumps or mats adjacent to or within seagrass beds, can provide additional food resources and habitat complexity, leading to increased animal abundance, but large concentrations can also inhibit faunal movements, smother benthic communities, and contribute to hypoxia, reducing nekton abundance. Despite its ubiquity,...

Drift macroalgae, often found in clumps or mats adjacent to or within seagrass beds, can increase the value of seagrass beds as habitat for nekton via added food resources and structural complexity. But, as algal biomass increases, it can also decrease light availability, inhibit faunal movements, smother benthic communities, and contribute to hypo...

Tropical cyclones drive coastal ecosystem dynamics, and their frequency, intensity, and spatial distribution are pre- dicted to shift with climate change. Patterns of resistance and resilience were synthesized for 4138 ecosystem time series from n = 26 storms occurring between 1985 and 2018 in the Northern Hemisphere to predict how coastal ecosyste...

Climate change is transforming ecosystems and affecting ecosystem goods and services. Along the Gulf of Mexico and Atlantic coasts of the southeastern United States, the frequency and intensity of extreme freeze events greatly influences whether coastal wetlands are dominated by freeze‐sensitive woody plants (mangrove forests) or freeze‐tolerant gr...

In this study we present results of a simultaneous survey of six turtlegrass -dominated ecosystems across the northern Gulf of Mexico. Our results indicate that regional variation in seagrass morphology is an important driver of nekton habitat use across the GOM, and suggests that models of nekton production in seagrass habitats should be regionall...

Small variations in environmental parameters can substantially alter species composition, but the extent to which different species respond to these changes remains obscure. A synoptic survey of seagrass-associated faunal communities was performed across the Gulf of Mexico using otter trawls coupled with seagrass and water quality assessments. The...

Many mollusks alter their shell morphology in response to predator exudates or injured conspecifics to lower their predation risk. However, studies have yet to examine whether this predator-avoidance response can be applied to bolster reef restoration, fisheries enhancement, or aquaculture. We tested whether exposure to predator cues under hatchery...

We conducted a large-scale survey of seagrass trophic structures across the northern Gulf of Mexico and presented preliminary data.

When prey alter behavioral or morphological traits to reduce predation risk, they often incur fitness costs through reduced growth and reproduction as well as increased mortality that are known as nonconsumptive effects (NCEs). Environmental context and trophic structure can individually alter the strength of NCEs, yet the interactive influence of...

Marine ecosystems face numerous challenges from natural and anthropogenic sources. For example, excessive rainfall from storms rapidly lowers salinity, which can destroy coastal foundation species and their associated fauna [1], while fishing can alter coastal food webs, reduce biodiversity, and lower ecosystem resilience [2]. Concurrently, mass di...

Mesopredator release following top predator loss may reduce biodiversity and harm foundation species. We investigated the potential for moderate environmental changes to trigger mesopredator release by disrupting the foraging ability of top predators without affecting their abundance by performing an in situ experiment designed to isolate the magni...

Turbidity is widely regarded for modulating primary production and influencing the distribution of submerged aquatic vegetation. Although less well studied, turbidity can also have significant effects on trophic interactions and food webs by modifying light penetration and scattering, influencing foraging ability of visual-hunting predators such as...

Presentation describing environmental drivers of seagrass community composition in the northern Gulf of Mexico

We conducted a landscape-scale simultaneous survey in turtlegrass (Thalassia testudinum) beds at six sites across the northern Gulf of Mexico to examine relationships between turtlegrass structural complexity and nekton communities. This poster details preliminary analysis of results.

Climate change is driving poleward shifts in species distributions worldwide. In the Gulf of Mexico (GOM), warming temperatures foster black mangrove (Avicennia germinans L.) expansion into GOM wetlands replacing wetland plants including Spartina alterniflora Loisel, Salicornia depressa L., and Batis maritima L. We investigated insect community ass...

This presentation describes the results of a paper to describe how different environmental factors drive changes in seagrass community composition for several key species that utilize seagrass habitat as juveniles.

Like predators, contaminant stressors such as pesticides may have large and interacting effects on natural communities by removing species or altering behaviors and species interactions. Yet, few studies in estuarine systems have evaluated the effects of a single, low-dose exposure to pesticides on key predators. Here, we investigated the effects o...

This presentation outlines preliminary results from a large-scale research project evaluating how nekton use seagrass habitat across the northern Gulf of Mexico.

Inducing defenses to deter predators is a necessary process theorized to incur costs. Although studies have investigated defense trade-offs, quantifying trade-offs is challenging and costs are often inferred. Additionally, prey employ strategies to reduce costs, making costs difficult to predict. Our purpose was to investigate induced defense costs...

Insecticide effects on nontarget organisms most commonly involve measuring mortality after single exposures. We examined sublethal effects of consecutive exposures of malathion, an organophosphate insecticide used for mosquito abatement, on the behavior of blue crabs (Callinectes sapidus). We measured righting time (i.e., time to return upright whe...

This poster is a summary of a planned research project to compare nekton habitat use in seagrass ecosystems across the northern Gulf of Mexico.

Many prey react to predation risk by altering their phenotype to reduce their chances of being consumed but incur reductions in growth and fecundity when reacting to predators. To determine when to produce defenses, prey collect information and evaluate the costs and benefits of defense induction. Resource availability can affect prey ability and w...

Climate change is facilitating black mangrove Avicennia germinans (L.) encroachment into Gulf of Mexico (GOM) estuaries, where mangroves are displacing Spartina alterniflora (Loisel) and other marsh plants. Western GOM estuaries have low tidal exchange, and salinity ranges from 0 to >50 ppt depending upon rainfall. Besides promoting expansion of tr...

Hydrodynamic forces associated with waves influence the structure and function of rocky intertidal communities, but their effects on species composition and morphology within other marine communities have not been well studied. We measured wave characteristics and current speeds with acoustic Doppler velocimeters (ADVs) at oyster (Crassostrea virgi...

By influencing critical prey traits such as foraging or habitat selection, predators can affect entire ecosystems, but the nature of cues that trigger prey reactions to predators are not well understood. Predators may scavenge to supplement their energetic needs and scavenging frequency may vary among individuals within a species due to preferences...

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Climate change is altering the distribution of foundation species, with potential effects on organisms that inhabit these environments and changes to valuable ecosystem functions. In the Gulf of Mexico, black mangroves (Avicennia germinans) are expanding northward into salt marshes dominated by Spartina alterniflora (hereafter Spartina). Salt marsh...

Oyster reefs are important components of marine ecosystems and function as essential habitat for estuarine species; however, few studies have simultaneously compared natural intertidal reefs to more well-studied seagrass meadows and marsh habitats. We investigated habitat use within an estuarine mosaic consisting of intertidal oyster reef (Crassost...

Prey often modify their behaviours to diminish predation risk, but the persistence of such behavioural changes are not well understood. We investigated the effects of predation risk in the aquatic mollusc Aplysia californica to determine whether various natural aversive stimuli alter the expression of feeding behaviour (i.e. bites) over short-term...

Numerous studies have examined how predator diets influence prey responses to predation risk, but the role predator diet plays in modulating prey responses remains equivocal. We reviewed 405 predator–prey studies in 109 published articles that investigated changes in prey responses when predators consumed different prey items. In 54 % of reviewed s...

Prey organisms reduce predation risk by altering their behavior, morphology, or life history. Avoiding or deterring predators often incurs costs, such as reductions in growth or fecundity. Prey minimize costs by limiting predator avoidance or deterrence to situations that pose significant risk of injury or death, requiring them to gather informatio...

Predation can significantly affect prey populations and communities, but predator effects can be attenuated when abiotic conditions interfere with foraging activities. In estuarine communities, turbidity can affect species richness and abundance and is changing in many areas because of coastal development. Many fish species are less efficient forag...

We investigated how changes in abiotic conditions resulting from human activities indirectly alter trophic interactions using turbidity in estuaries as a model system. Development and nutrient input are causing turbidity to increase in many coastal areas. Using an 18 yr data set from Aransas and San Antonio Bays in Texas, we found fish abundance (S...

The objective of this study was to measure the communities associated with different seagrass species to predict how shifts in seagrass species composition may affect associated fauna. In the northwestern Gulf of Mexico, coverage of the historically dominant shoal grass (Halodule wrightii) is decreasing, while coverage of manatee grass (Syringodium...

Background/Question/Methods As populations decline, their intraspecific diversity may diminish. Population decline may be exacerbated if a decrease in intraspecific diversity also reduces important ecological functions that maintain population numbers. Oyster reefs are severely overharvested, declining by ~85% worldwide. We tested how increasing w...

Abstract Nonconsumptive effects (NCEs) have been shown to occur in numerous systems and are regarded as important mechanisms by which predation structures natural communities. Sensory ecology-that is, the processes governing the production, propagation, and masking of cues by ambient noise-provides insights into the strength of NCEs as functions of...

Predators often have large effects on prey populations and entire communities, but the nature of top-down control in speciose food webs is often difficult to assess due to consumer interactions such as complementarity, predator interference, and omnivory. To assess how top and intermediate predators affect community structure, we used predator excl...

Biotic and abiotic conditions can separately and synergistically influence the abundance and distribution of species and create vertical zonation patterns in marine systems. In Corpus Christi Bay, TX, USA, eastern oysters (Crassostrea virginica) are limited to intertidal habitats, while in adjacent estuaries, oysters not only grow subtidally, but t...

Many prey species alter their behavior and/or morphology in response to exudates from predators and injured con- or heterospecifics to alleviate predation risk. Yet, few studies have assessed the effectiveness of risk aversion in prey in terms of decreasing mortality. Recent studies have shown that eastern oysters Crassostrea virginica produce heav...

A comparative study of three imaging technologies has been conducted to nondestructively assess the thickness and strength of oyster shells grown in various environmental conditions. Oyster shell thickness and strength are expected to be dependent on the harshness of the oyster's environment as well as other factors. Oysters have been grown in envi...

The expression of prey antipredator defenses is often related to ambient consumer pressure, and prey express greater defenses under intense consumer pressure. Predation is generally greater at lower latitudes, and antipredator defenses often display a biogeographic pattern. Predation pressure may also vary significantly between habitats within lati...

As populations decline, their intraspecific diversity also diminishes. Population decline may be exacerbated if a decrease in intraspecific diversity also reduces important ecological functions that maintain population numbers. Oyster reefs are severely overharvested, declining by ~85 % worldwide. We tested how increasing within-species diversity o...

Nonlethal predator effects can significantly influence trophic interactions, and in this study we examined how size relationships between predators and prey would influence the expression of nonlethal predator effects. We assessed how size and vulnerability to predators would influence nonlethal effects in bivalve species common to oyster reefs. We...

To reduce their risk of being eaten, prey may change their morphology or behavior in response to predators, which can result in slower growth and lower fitness. To minimize costs, prey limit anti-predator responses to risky situations, which requires prey to reliably detect cues indicative of predation risk. The purpose of this study was to ascerta...

Stramonita haemastoma, the southern oyster drill, is a predatory gastropod that locates prey using waterborne chemical cues. These cues move by advection and are subjected to hydrodynamic forces such as turbulence, which can have significant effects on both the delivery of cues and on the efficiency and success of organisms that use chemical cues t...

Predators can strongly influence prey populations and the structure and function of ecosystems, but these effects can be modified by environmental stress. For example, fluid velocity and turbulence can alter the impact of predators by limiting their environmental range and altering their foraging ability. We investigated how hydrodynamics affected...

Predators can strongly influence prey populations and the structure and function of communities by altering the foraging behavior and/or habitat selection of prey. For these nonlethal predator effects to occur, prey must be able to detect and respond to cues indicating predation risk. The ability of prey to detect and respond to predator signals li...

The ability of prey to detect and adequately respond to predation risk influences immediate survival and overall fitness. Chemical cues are commonly used by prey to evaluate risk, and the purpose of this study was to elicit the nature of cues used by prey hunted by generalist predators. Nucella lapillus are common, predatory, intertidal snails that...

Background/Question/Methods As summarized in a variety of experimental studies and reviews, predators commonly have large impacts on prey populations and community organization through lethal or consumptive effects (CEs) and by nonlethal or nonconsumptive effects (NCEs) whereby predators cause prey to alter their morphology, behavior, and/or habita...

Predators often have large effects on community structure, but these effects can be minimized in habitats subjected to intense physical stress. For example, predators exert large effects on rocky intertidal communities on wave-protected shores but are usually absent from wave-swept shores where hydrodynamic forces prevent them from foraging effecti...

Soft-shell clams, Mya arenaria, are sessile, suspension-feeding bivalves that are preyed upon by the exotic green crab, Carcinus maenas. Clams evade crab consumers by burrowing deeper into the sediment after perceiving a threat from a nearby predator. The purpose of this study was to determine the types of signals that M. arenaria use to detect pre...

Although manatee grass is becoming increasingly abundant in Texas bays, its growth characteristics have not been measured in the western GOM. Changes in seagrass species composition can have significant community effects (Micheli et al. 2008), but the effects of a transition from shoal to manatee grass in the LM have not been extensively studied (b...

Organophosphate insecticides can compromise water quality and harm non-target species unintentionally. In this study, we examined the effects of a commonly used organophosphate insecticide, Malathion, on blue crabs Callinectes sapidus, which are an economically and ecologically important estuarine species. Adult and juvenile crabs were exposed to e...

Background/Question/Methods We studied microsatellites to quantify levels of genetic variation in the eastern oyster (Crassostrea virginica) within and among Texas bays. By determining the level of diversity, we will provide information that may be used to improve restoration. Although oysters have pelagic larvae that can travel long distances, du...

Habitat complexity often modifies rates of prey capture by visual predators, but little is known about how structural features affect non-visual olfactory consumers. Laboratory studies indi- cate that turbulent water flow over complex bedforms mixes chemical information in ways that con- fuse some olfactory foragers but improve the odor-tracking ab...

Previous studies have shown that prey living under intense consumer pressure possess stronger defenses against consumers than related species in habitats where consumer pressure is low. We tested whether prey sensitivity to risk would be heightened in habitats with elevated preda- tion pressure and accordingly whether prey living in these areas wou...

Many studies have shown that nonlethal predator effects such as trait-mediated interactions (TMIs) can have significant impacts on the structure and function of communities, but the role that environmental conditions play in modulating the scale and magnitude of these effects has not been carefully investigated. TMIs occur when prey exhibit behavio...

The lethal and nonlethal impacts of predators in marine systems are often mediated via reciprocal detection of waterborne chemical signals between consumers and prey. Local flow environments can enhance or impair the chemoreception ability of consumers, but the effect of hydrodynamics on detection of predation risk by prey has not been investigated...

Hard clams, Mercenaria mercenaria, are sessile, filter-feeding organisms that are heavily preyed upon by blue crabs, which find their clam prey using chemical cues. Clams may evade blue crabs by reducing their pumping (feeding) behavior when a threat is perceived. The purpose of this study was to determine the type of signals that clams use to dete...

Hard clams, Mercenaria mercenaria, are slow-moving organisms that are heavily preyed upon by both blue crabs and knobbed whelks in coastal Georgia. Hard clams are unable to escape from these predators, and when found, are commonly injured and/or consumed. Thus, their best survival strategy is to avoid their predators. In this study, we compared cha...

The selective advantage of avoiding lethal predation typically outweighs the benefits of obtaining food. Many aquatic organisms reduce their foraging activity after detecting the presence of injured conspecifics, but responses of cannibalistic animals are less obvious because injury-related cues might attract rather than deter alerted consumers. We...

Foraging blue crabs must respond to fluid forces imposed on their body while acquiring useful chemical signals from turbulent odor plumes. This study examines how blue crabs manage these simultaneous demands. The drag force, and hence the cost of locomotion, experienced by blue crabs is shown to be a function of the body orientation angle relative...

To locate food, mobile consumers in aquatic habitats perceive and move towards sources of attractive chemicals. There has been much progress in understanding how consumers use chemicals to identify and locate prey despite the elusive identity of odor signals and the complex effects of turbulence on chemical dispersion. This review highlights how in...