Final Report: Pre-Construction Study of Bats and Birds at Cerro Izopo, Honduras
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Final Report: Pre-construction Study of Bats and Birds at Cerro Izopo, Honduras Common Vampire Bat (Desmodus rotundus ), 20 September 2013 (Photo Roselvy Juárez) 30 September 2013 Oliver Komar, Ph.D., Principal Investigator José Mora, Ph.D., Co-Principal Investigator John van Dort, M.A., Field Coordinator Centro Zamorano de Biodiversidad Departamento de Ambiente y Desarrollo Escuela Agrícola Panamericana (Zamorano) San Antonio de Oriente, Francisco Morazán, Honduras Contacts: [email protected], [email protected] TABLE OF CONTENTS ACKNOWLEDGEMENTS 1 SUMMARY 2 INTRODUCTION 2 DESCRIPTION OF AREA 2 METHODS 3 BATS 4 BIRDS 5 RESULTS 6 BATS 6 BIRDS 8 DISCUSSION 14 BATS 14 BIRDS 14 REFERENCES 16 ANNEXES 17 ANNEX 1: BAT SPECIES DETECTED IN CERRO IZOPO, AREA 14, DURING SEPTEMBER 2013 17 ANNEX 2: BIRD SPECIES DETECTED IN CERRO IZOPO, AREA 14, DURING SEPTEMBER 2013 19 ANNEX 3: BAT CAPTURES WITH MIST-NETS PER POINT 23 ANNEX 4: BAT CAPTURES WITH HARP TRAP PER POINT 23 ANNEX 5: NUMBER OF RECORDINGS (ANABAT) PER SPECIES PER POINT 23 ANNEX 6: BIRDS RECORDED AT POINT COUNTS PER POINT (HIGH COUNT OF THREE SAMPLING SESSIONS) PER SPECIES DURING SEPTEMBER 2013 24 ANNEX 7: PHOTO COLLAGE OF BAT SPECIES SAMPLED WITH MIST-NETS 26 ANNEX 8: EXAMPLES OF SONOGRAMS OF BAT VOCALIZATIONS OBTAINED DURING THE PRESENT STUDY 28 Acknowledgements EEHSA provided the funding for this study. We wish to thank Scarleth Núñez of EEHSA for logistics support, as well as the following EEHSA Security Staff for their valuable assistance in the field: Héctor Ávila, Melvin Flores, Melvin García, Victor García, Alfredo Gómez, Rolando Mejía, Luis Rivera, José Ernesto Ruíz, and Keni Salazar. We also thank ICF for granting research permission, and Roselvy Juárez and Carlos Funes for collecting bat data in the field. 1 Summary Preconstruction field work sampling bat and bird communities in Area 14 took place in September 2013. The presence of 18 bat species and 85 bird species was detected. All bat and bird species had been recorded in the Cerro de Hula wind facility previously. An average of 4.8 bat species and 13.9 bird species was found per sampling point. None of the bat species encountered has an IUCN conservation status other than Least Concern. Three of the bird species encountered have an IUCN status other than Least Concern: Olive-sided Flycatcher (Near-Threatened), Cerulean Warbler (Vulnerable) and Golden-cheeked Warbler (Endangered). All three species are Neotropical migrants that are either transient in Honduras (Cerulean Warbler, Olive-sided Flycatcher) or winter visitors (Golden-cheeked Warbler). As nocturnal migrants, all three species may be considered potential turbine strike victims. However, none of these species was detected as a strike victim during the first year of mortality monitoring in the Cerro de Hula wind facility. Introduction The Cerro de Hula wind facility began operations in October 2011, with an initial set of 51 turbines. In 2013, Energía Eólica de Honduras SA (EEHSA) planned an expansion of the park with six additional turbines, the majority to be located near the El Tablón community on Cerro Izopo (Area 14). In August 2013, EEHSA commissioned the Escuela Agrícola Panamericana (Zamorano University) to evaluate species’ richness and relative abundance of bat and bird communities in the area selected for second phase construction of wind turbines within the municipality of San Buenaventura, Francisco Morazán. Here we present the results of a field evaluation of bat and bird populations in Area 14. The area is located in close proximity (approximately 1 km) to first phase turbines erected in 2011. Thus, while this report reflects pre-construction inventory work carried out in this additional area, we caution against interpreting the results as purely “preconstruction”, as it seems reasonable to assume that bat and avian communities in the current study area utilize these nearby postconstruction areas as well. Description of area Field work took place near the El Tablón community on Cerro Izopo, in an area designated by EEHSA as “Area 14”, where the construction of a total of five turbines is scheduled. One additional turbine is planned for Area 4, on Cerro de Hula, in the municipality of Santa Ana. Since the bird and bat communities of Area 4 have already been sampled both preconstruction (Pandion 2010) and postconstruction (Zamorano 2013), and the extension of that area is limited to one turbine only in close proximity to existing turbines, we did not consider it appropriate to collect additional field data from that area. 2 Figure 1: Area 14, Cerro Izopo. The top yellow pins show the 10 sampling points, while the blue dots show the planned locations of the new turbines; lower yellow pins show existing first phase turbines on Cerro Izopo of Areas 9 and 10. Area 14 is located on the north slope of Cerro Izopo (N13°55’48”, W87°09’18”), approximately 13 km south-southeast of Tegucigalpa, 1 km north from the nearest existing turbines of Area 10, and 1.5 km northeast from the nearest existing turbines of Area 9 (Figure 1). The designated construction area is situated on a level ridge at approximately 1670 masl, surrounded by steep forested hillsides that drop 100–300 m. Habitats present in the study area consist of highly fragmented humid pine-oak and second-growth cloud forest patches (estimated at approximately 30%), and scattered agricultural plots (estimated at approximately 70%). Most agricultural plots were used for corn, and to a much lesser degree cabbage and coffee. Methods Field work took place in September 2013. Field data for bats and birds was collected at 10 points, each spaced at least 200 m from one another, distributed in an area roughly corresponding to the planned constructions of the five turbines (Figure 1). Location of the points was generally chosen within the small level ridge at sites with transitional habitat, i.e. edges of fields bordering on forest, to account for the dominance of these edge habitats in the area, while also avoiding the necessity to clear corn cultivation for mist-netting, or the possibility to inadvertently locate 3 points at substantially lower elevations, where bat and bird communities may be different (Table 1). Table 1: Sampling locations Point Coordinates 1 13°55’57.3”N 87°09’33.7”W 2 13°55’51.4”N 87°09’29.6”W 3 13°55’51.8”N 87°09’22.7”W 4 13°55’49.8”N 87°09’16.3”W 5 13°55’55.9”N 87°09’09.1”W 6 13°55’49.2”N 87°09’08.0”W 7 13°55’42.2”N 87°09’12.7”W 8 13°55’43.1”N 87°09’05.3”W 9 13°55’36.4”N 87°09’15.2”W 10 13°55’36.4”N 87°09’07.1”W Bats Sampling of the bat community was stratified to three complementary methods, to account for inherent detection differences between these methods. Thus, low-flying species (many of which include nectarivores and frugivores) were primarily sampled with 4 mist-nets, each 12 m long and 2.5 m high, low-flying insectivores were targeted with a harp trap (Figure 2), while higher-flying species (many of which include insectivores) were primarily sampled with acoustic equipment (Anabat), to be identified based on species’ unique vocal signatures. Bat sampling took place between 6 PM and midnight, during good weather. The mist-nets and harp trap were checked at least once every hour (once every half hour or more frequently in case of light, intermittent rain), and bats thus encountered were removed, measured, sexed, identified to species, and released. The sampling effort was 248 net hours for mist-netting and 53 hours for the harp trap. Acoustic sampling was carried out simultaneously and at the same location for one hour each night, broken up into smaller segments of 10–15 minutes at a time. Calls emitted by overflying bats were recorded with Anabat equipment, and these recordings were later converted to sonograms. The sonograms were then compared to a reference library of vocal signatures of known species, and thus identified to species (O’Farrell 1997, O’Farrell & Miller 1997, O’Farrell & Miller 1999, Ochoa et al. 2000). To measure relative abundance in bats, we combined the mist-netting and harp trap results, leaving out the acoustic monitoring. The first two methods allow a quantitative analysis, while acoustic monitoring of free-flying bats is better suited for a qualitative approach (O’Farrell et al. 1999). We present species richness per point as a sum of all species recorded at the point using all three sampling methods. We present relative abundance of bats per point as a sum of all individuals of all species present at each individual point using only mist-netting and harp trap methods. 4 Figure 2: Setting up the harp trap. EEHSA Security staff not only provided security assistance but often also field assistance. Photo: Roselvy Juárez. Birds Sampling of the bird community consisted of fixed-radius point counts (Hutto et al. 1986) carried out by one skilled observer familiar with the identification of all species, resident and migrant, expected to occur in the area. Bird point counts were carried out at the same 10 points as used for bat sampling. Each point was visited 3 times for a duration of 10 minutes per visit, i.e. 30 minutes sampling effort per point. All birds detected within a circumference of 50 m of the point were recorded as present at the point. To avoid double counts, the highest number of individuals for each species present at the point during one of those three counts was selected for analysis.