Project Work Plan

Greater Everglades Science Program: Place-Based Studies

Project Work Plan FY 2003

A. GENERAL INFORMATION:

Project Title: Response Of Roseate Spoonbills Nesting In Florida Bay To Hydrologic Restoration: A Performance Measure Of Everglades Restoration

Project start date: 10/1/2002 Project end date: 9/30/05
Principal Investigator: Jerome J. Lorenz
Email address: jlorenz@audubon.org
Phone: 305-852-5092 Fax: 305-852-8012
Mail address: 115 Indian Mound Trail, Tavernier, FL 33070

Co-principal Investigator(s): Robert E. Bennetts
Email address: rbennetts@USGS.gov
Phone: 352-378-8181 x 374 Fax: 352-378-4956
Mail address: 7920 NW 71st St., Gainesville, FL 32653

Project Summary: Our project is designed to evaluate the effect of hydrologic restoration on the nesting distribution and success of Roseate Spoonbills (Ajaia ajaia) in Florida Bay and surrounding mangrove estuarine habitats. This project is further designed to test hypotheses about the causal mechanisms of observed changes. The Everglades ecosystem has suffered extensive degradation over the past century, including an 85-90% decrease in the numbers of wading birds. Previous monitoring of Roseate Spoonbills in Florida Bay over the past 50 years has shown that this species responds markedly to changes in hydrology and corresponding changes in prey abundance and availability. Shifts in nesting distribution and declines in nest success have been attributed to declines in prey populations as a direct result of water management. Consequently, the re-establishment of spoonbill colonies in northeast Florida Bay is one change predicted under a conceptual model of the mangrove estuarine transition zone of Florida Bay. Changes in nesting distribution and success will further be used as a performance measure for success of restoration efforts and will be incorporated in a model linking mangrove fish populations and spoonbills to alternative hydrologic scenarios.

Project Objectives and Strategy: The primary objectives of our research are to (1) quantify the changes in spatial distribution and success of nesting spoonbills relative to hydrologic patterns, (2) test hypotheses about the causal mechanisms for observed changes, (3) establish a science-based criteria for nesting distribution and success to be used as a performance measure for hydrologic restoration, and (4) estimate demographic parameters. To meet these objectives, we will use a combined field/modeling approach. Based on previous and concurrent research, hypothesized relationships between hydrology, fish populations, and spoonbill nesting distribution and success will be expressed in a simple, but spatially explicit, conceptual model. Field data will be collected and compared with predicted responses to monitor changes in spoonbill nesting as hydrologic restoration is implemented, and to test the hypothesized mechanisms for observed changes. Variation of hydrologic conditions among years and locations is a virtual certainty; thus we will treat this variation in a quasi-experimental framework where the variation in wet and dry season conditions constitutes a series of "natural experiments".

Potential Impacts and Major Products: The re-establishment of healthy wading bird populations in the Everglades system has been at the forefront of restoration goals since its inception, and the Roseate Spoonbill has been frequently identified as one of the key indicator species for restoration of the estuarine system. Thus, monitoring changes in the distribution and abundance of this species will provide a valuable measure of successful restoration. However, this study goes beyond a measure of success in that the methods we have proposed enable us to evaluate alternative hypotheses for the causal mechanisms of observed changes. We will be able to use annual variation in spoonbill response in a quasi-experimental context to test hypotheses, while simultaneously using the cumulative changes over longer time scales to evaluate the success of restoration efforts.

The data collected from this study would be published in peer-reviewed scientific journals; thus, would provide a credible basis for supporting decisions made by management agencies. Further, the conceptual model developed on this project would be formalized and made available to management agencies through a collaborative effort with the ATLSS modeling project. This model could be used by management agencies as an exploratory tool to evaluate alternative management actions and scenarios.

Collaborators: Donald L. DeAngelis, USGS, University of Miami, Florida
Jon C. Cline, TIEM, University of Tennessee

Clients: U. S. Geological Survey, South Florida Ecosystem Initiative scientists, U.S. Army Corps of Engineers, South Florida Water Management District will use results of this research. It is expected that the information provided by this project will be used by management agencies in South Florida to implement and refine hydrologic restoration strategies.

B. WORK PLAN

Title of Task 1: Conceptual model of spoonbill/fish/hydrology
Task Funding: PBS
Task Leaders: Jerome Lorenz, Robert Bennetts
Phone: 303-541-3036
Fax: 305-852-5092
Task Status (proposed or active): proposed
Task priority: high
Task Personnel: Jerome Lorenz, Robert Bennetts

Task Summary and Objectives: Based on previous research, develop an initial conceptual model that summarizes the relationship among the distribution and success of nesting spoonbills, the abundance and availability of mangrove fishes, and hydrology. This model should enable predictions about how nesting spoonbills and fishes should respond to a given set of hydrologic conditions. As such, the data collected during this study will constitutes a validation of the initial conceptual model. The validation process, then also serves as a mechanism by which this initial model can be refined.

Work to be undertaken during the proposal year and a description of the methods and procedures: FY03:

1. Synthesize existing research on the relationship between water levels, mangrove fishes, and the distribution and success of nesting spoonbills. Express these relationships in terms of hypotheses regarding wet and dry season water levels and the response by fishes and spoonbills. Establish preliminary quantitative relationship among relevant parameters which enable predictions of hypothesized relationships.
2. Collaborate with ATLSS modeling team to formalize the conceptual model into a preliminary working model that can be used to compare hypothesized and observed responses to hydrologic variation.

Title of Task 2: Estimate numbers, distribution, and success of nesting Roseate Spoonbills
Task Funding: PBS
Task Leaders: Jerome Lorenz, Robert Bennetts
Phone: 303-541-3036
Fax: 305-852-5092
Task Status (proposed or active): proposed
Task priority: high
Task Personnel: 1 post-doctoral research associate, 4 field technicians

Task Summary and Objectives: All islands previously reported to have spoonbill colonies will be surveyed at least twice during the nesting season and the number of spoonbill nests counted. Colonies will be grouped into five subregions based on proximal foraging location for each. The two largest colonies within each of five subregions will be used to estimate nesting success for each group.

Work to be undertaken during the proposal year and a description of the methods and procedures:
FY 03:

1. Spoonbill nests are generally located in dense red mangrove stands and are not generally visible from outside the colony. Therefore, all possible colonies locations must be visited by researchers in order to get an accurate nest count for Florida Bay. While traversing Florida Bay by boat, locations of Roseate Spoonbill activity will be investigated for new nesting sites.
2. The two largest colonies within each colony group will be used to estimate nesting success for each group. Survey transects will be established in each of these colonies so that representative samples of nests can be monitored. Each colony will be visited approximately every ten days and the contents of each nest were recorded.

Title of Task 3: Assessment of foraging location
Task Funding: PBS
Task Leaders: Jerome Lorenz, Robert Bennetts
Phone: 303-541-3036
Fax: 305-852-5092
Task Status (proposed or active): proposed
Task priority: high
Task Personnel: 1 post-doctoral research associate, 4 field technicians

Task Summary and Objectives: In order to use nesting effort and nest success as criteria for ecosystem evaluation, the location of primary foraging grounds must be known for each colony group. This enables predictions about the response of mangrove fishes and nesting spoonbills to be directly evaluated in relation to hydrologic conditions relevant to a particular colony.

Work to be undertaken during the proposal year and a description of the methods and procedures: FY03:

1. Flight line counts will be made at the two largest colonies in each colony group. Initially, the colony island will be circumnavigated by boat in order to determine the least number of positions needed to observe birds arriving and leaving the colony from any direction. Once identified, the boat will be anchored at each position for a predetermined amount of time and the number and direction (compass heading) of Roseate Spoonbills arriving and leaving the colony counted. The results of these observation will indicate the direction of the primary foraging grounds for the colony groups.
2. Although the flight line count technique is widely accepted in the study of wading bird foraging pattern, supplemental data from following flights would greatly increase the credibility of these observations and enable specific foraging destinations to be determined. Individual birds will be followed using a fixed-wing aircraft from their nesting colonies to the first foraging location.

Title of Task 4: Estimation of demographic parameters
Task Funding: PBS
Task Leaders: Jerome Lorenz, Robert Bennetts
Phone: 303-541-3036
Fax: 305-852-5092
Task Status (proposed or active): proposed
Task priority: high
Task Personnel: 1 post-doctoral research associate, 4 field technicians

Task Summary and Objectives: Nesting activity for Roseate Spoonbills has been monitored since 1950; however, there has been no effort to date to directly relate demography and environmental conditions, with the exception of nesting success. Direct estimation of demographic parameters would enable us to better understand the demographic mechanisms of observed responses by spoonbills (e.g., to distinguish numerical from behavioral responses). Consequently, we will use capture-resighting to estimate (1) survival of nestlings from branching until fledging, (2) survival of juveniles and adults, (3) recruitment into the breeding population, and (4) breeding dispersal.

Work to be undertaken during the proposal year and a description of the methods and procedures: FY03:

1. Nestlings would be banded with both USFWS and individually-numbered PVC bands between the ages of 7-14 days. This would be concurrent with nest checks used to determine nesting success.
2. Resighting of banded nestlings during FY2003 would occur just prior to dispersal to enable estimation of survival from the time of branching to the time of dispersal. In subsequent years, resightings of adults will also occur at the nest and during staging just prior to nest initiation.