C-111 Project & Cape Sable Seaside Sparrow
Total Page:16
File Type:pdf, Size:1020Kb
C-111 PROJECT & CAPE SABLE SEASIDE SPARROW SUBPOPULATION D: BASELINE DATA ON SPARROWS, VEGETATION AND HYDROLOGY ANNUAL REPORT – 2011 1,2 1 THOMAS VIRZI , MICHELLE J. DAVIS , 3 3,4 3 JAY P. SAH , MICHAEL S. ROSS AND PABLO L. RUIZ 1Department of Ecology, Evolution and Natural Resources Rutgers, The State University of New Jersey, New Brunswick, NJ 08901 2Grant F. Walton Center for Remote Sensing and Spatial Analysis Rutgers, The State University of New Jersey, New Brunswick, NJ 08901 3Southeast Environmental Research Center, Florida International University, Miami, FL 33199 4Department of Earth and Environment, Florida International University, Miami, FL 33199 REPORT TO THE SOUTH FLORIDA WATER MANAGEMENT DISTRICT SEPTEMBER 2011 Contents 1.0 EXECUTIVE SUMMARY .............................................................................................................................. 3 2.0 INTRODUCTION ......................................................................................................................................... 7 2.1 PURPOSE ......................................................................................................................................................... 7 2.2 SPARROW ECOLOGY ........................................................................................................................................ 11 2.3 FIGURES ........................................................................................................................................................ 15 3.0 CAPE SABLE SEASIDE SPARROW DISTRIBUTION AND DEMOGRAPHY IN SUBPOPULATION D .................. 18 3.1 BACKGROUND ................................................................................................................................................ 18 3.2 METHODS ..................................................................................................................................................... 19 3.3 RESULTS AND DISCUSSION ................................................................................................................................ 21 3.4 TABLES AND FIGURES ....................................................................................................................................... 30 4.0 VEGETATION STRUCTURE AND COMPOSITION WITHIN SPARROW SUBPOPULATION D HABITAT ........... 39 4.1 BACKGROUND ................................................................................................................................................ 39 4.2 METHODS ..................................................................................................................................................... 40 4.3 RESULTS AND DISCUSSION ................................................................................................................................ 42 4.4 TABLES AND FIGURES ....................................................................................................................................... 48 5.0 LITERATURE CITED ................................................................................................................................... 61 6.0 APPENDICES ............................................................................................................................................ 66 6.1 APPENDIX 1 ................................................................................................................................................... 66 6.2 APPENDIX 2 ................................................................................................................................................... 69 6.3 APPENDIX 3 ................................................................................................................................................... 72 6.4 APPENDIX 4 ................................................................................................................................................... 75 6.5 APPENDIX 5 ................................................................................................................................................... 78 6.6 APPENDIX 6 ................................................................................................................................................... 79 6.7 APPENDIX 7 ................................................................................................................................................... 80 2 1.0 Executive Summary The main purpose of this report is to provide baseline conditions on Cape Sable seaside sparrow (CSSS or the “sparrow”) populations and habitat in small sparrow subpopulation D before implementation of the C-111 Spreader Canal Western Phase I Project (C-111 SC Project). The C- 111 SC Project was designed to restore the quantity, timing and distribution of water delivered to Florida Bay via Taylor Slough and to improve hydroperiod and hydropattern in the area south of the C-111 Canal known as the Southern Glades and Model Lands. The U.S. Fish and Wildlife Service (USFWS or the “Service”) issued a Biological Opinion dated August 25, 2009 addressing concerns over potential effects of the C-111 SC Project on CSSS populations and designated sparrow critical habitat, including subpopulation D which is located in the eastern portion of the Everglades just east of Taylor Slough and west of the C-111 Canal. As part of the USFWS Biological Opinion, the South Florida Water Management District (SFWMD or the “District”) is required to measure the impact of the C-111 SC Project on sparrows and habitat in subpopulation D. As a result, the District contracted Dr. Thomas Virzi of Rutgers University (Rutgers) to provide expert advice regarding the sparrow population, and Dr. Jay P. Sah and Dr. Michael S. Ross of Florida International University (FIU) to provide expert advice regarding sparrow habitat. This report is divided into three main sections. Section 2.0 is an introduction to this report, providing an overview of the C-111 SC Project and sparrow ecology. Section 3.0 provides a summary of historic data on the CSSS population in subpopulation D and reports the results of field research on sparrow distribution and demography conducted by Rutgers during the 2011 sparrow breeding season. Section 4.0 provides a summary of historic data on CSSS habitat in subpopulation D and reports the results of field research on vegetation structure and composition conducted by FIU during the 2011 sparrow breeding season. An overview of these sections is provided below. The final two sections of this report provide tables and figures (Section 5.0) and appendices (Section 6.0). 3 Section 2.0 In the USFWS Biological Opinion dated August 29, 2009, the Service concurred with the determination by the U.S. Army Corps of Engineers (USACE or the “Corps”) that the C-111 SC Project “may affect, and is likely to affect” the endangered CSSS, and that the project “will affect” designated CSSS critical habitat. Computer simulation modeling indicated that local conditions within CSSS subpopulation D critical habitat may be adversely affected by the C-111 SC Project resulting in an increased hydroperiod in the area. Although CSSS numbers are extremely low in subpopulation D (<10 sparrows typically), there is concern over recent declines in all of the small, spatially isolated sparrow subpopulations. The recent declines across all small sparrow subpopulations (A, C, D and F) have been attributed to anthropogenic changes in water flows in the Everglades ecosystem. The federally endangered CSSS is restricted to short-hydroperiod marl prairies in the southern Everglades, and this habitat has been adversely affected by hydrologic changes ranging from too much water in some areas (e.g. subpopulations A and D) to too little water in other areas (e.g. subpopulations C and F). Further, high water levels have been associated with reduced occupancy of sites and reduced reproductive performance. Due to the restricted range of the CSSS and the limited number (and condition) of remaining subpopulations, the potential loss of any sparrow subpopulation increases the probability of extinction for the entire species. Thus, any potential anthropogenic changes to hydrologic conditions in subpopulation D that may adversely affect sparrow breeding habitat must be monitored closely. Section 3.0 The first complete sparrow survey, conducted by Everglades National Park (ENP) in 1981, estimated the sparrow population at 400 birds in subpopulation D. A repeat survey in 1992 reported a dramatic decline in sparrow numbers subpopulation D, similar to declines reported for other sparrow subpopulations, attributing the decline to an increased hydroperiod in the area. Since then, sparrow occupancy and abundance only recently began to show any sign of improvement (past 3 years) likely as the result of a recent drying trend; however, the population remains extremely small (7 sparrows in 2011). Intensive ground surveys conducted 4 since 2006 show that sparrows have generally used the same area for breeding each year with territories concentrated in a small patch of suitable habitat in the northwestern-central portion of the subpopulation. Breeding has occurred sporadically since 2006; however, no breeding occurred in 2011. A major concern in subpopulation D is the severely male-biased sex ratio reported in most years (e.g. 6 males and 1 female in 2011), which has led to very low overall annual productivity due to the lack of enough females in the