Publications

Perturbation analysis is a powerful tool to study population and community dynamics. This article describes expressions for sensitivity metrics reflecting changes in equilibrium occupancy resulting from small changes in the vital rates of patch occupancy dynamics (i.e., probabilities of local patch colonization and extinction). We illustrate our approach with a case study of occupancy...

1. Savanna ecosystems – defined by the coexistence of trees and grasses – cover more than one‐fifth the world’s land surface and harbour most of the world’s rangelands, livestock and large mammal diversity. Savanna trees can have a variety of effects on grasses, with consequences for the wild and domestic herbivores that depend on them. 2. Studies of these effects have focused on two...

This study quantified the hypoxia tolerance of the Mayan cichlid Cichlasoma urophthalmus over a range of salinities. The species was very tolerant of hypoxia, using aquatic surface respiration (ASR) and buccal bubble holding when oxygen tensions dropped to

Yellow bullhead (Ictaluridae: Ameiurus natalis) is the most abundant ictalurid catfish in the Everglades of southern Florida, USA, and, as both prey and predator, is one of many essential components in the ecological-simulation models used in assessing restoration success in the Everglades. Little is known of its biology and life history in this southernmost portion of its native range...

Plant populations may adapt to environmental conditions over time by developing genetically based morphological or physiological characteristics. For tidal freshwater forested wetlands, we hypothesized that the conditions under which trees developed led to ecotypic difference in response of progeny to hydroperiod. Specifically, we looked for evidence of ecotypic adaptation for tidal...

Feeding opportunities of American alligators (Alligator mississippiensis) in freshwater wetlands in south Florida are closely linked to hydrologic conditions. In the Everglades, seasonally and annually fluctuating surface water levels affect populations of aquatic organisms that alligators consume. Since prey becomes more concentrated when water depth decreases, we hypothesized an...

The regularity and severity of tropical storms are major determinants controlling ecosystem structure and succession for coastal ecosystems. Hurricane landfall rates vary greatly with high and low frequency for given coastal stretches of the southeastern United States. Site-specific meteorological data of hurricane wind speeds and direction, however, are only available for select...

Many low‐elevation dry forests of the western United States contain more small trees and fewer large trees, more down woody debris, and less diverse and vigorous understory plant communities compared to conditions under historical fire regimes. These altered structural conditions may contribute to increased probability of unnaturally severe wildfires, susceptibility to uncharacteristic...

We model effects of interspecific plant competition, herbivory, and a plant's toxic defenses against herbivores on vegetation dynamics. The model predicts that, when a generalist herbivore feeds in the absence of plant toxins, adaptive foraging generally increases the probability of coexistence of plant species populations, because the herbivore switches more of its effort to whichever...

This paper describes direct video observations of two manefishes, likely Paracaristius sp., from the mesopelagic waters of the north-central Gulf of Mexico. One fish was observed with a remotely operated vehicle at a depth of 829 m by an industrial ROV as part of the SERPENT Project. The second was observed at 496 m from a manned submersible. Little is known about the behavior of...

Usually, fibroblasts are frozen in dimethyl sulphoxide (DMSO, 10% v/v) at a cooling rate of 1 °C/min in a low-temperature (−80 °C) freezer (LTF) before storage in liquid nitrogen (LN2); however, a LTF is not always available. The purpose of the present study was to evaluate apoptosis and viability of bovine fibroblasts frozen in a LTF or conventional freezer (CF; −20 °C) and their...

This report documents changes in forest structure and growth potential of dominant trees in salt-impacted tidal and non-tidal baldcypress wetlands of the southeastern United States. We inventoried basal area and tree height, and monitored incremental growth (in basal area) of codominant baldcypress (Taxodium distichum) trees monthly, for over four years, to examine the inter...