Banca de DEFESA: JUAN CARLOS VARGAS MENA
Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.STUDENT : JUAN CARLOS VARGAS MENA
DATE: 05/03/2020
TIME: 09:00
LOCAL: Laboratório Didático I
TITLE:
The spatial and temporal structure of bat (Chiroptera) assemblages in Caatinga dry forests in northeastern Brazil
KEY WORDS:
Caves, cave-roosting, Chiroptera, conservation, beta diversity, new records, Seasonal dry tropical forests, trophic guilds, reproduction
PAGES: 151
BIG AREA: Ciências Biológicas
AREA: Ecologia
SUMMARY:
Seasonal Dry Tropical Forests (SDTF), such as the Caatinga, are considered adverse In the Caatinga dry forest, key factors that controls the structure and dynamics of the bat assemblages have been attributed to the spatial heterogeneity of different ecoregions and phytofisiognomies,and to seasonality of rain and pulses of food resource. Almost 95% of Rio Grande do Norte (RN) state correspond to Caatinga where it harbors abundant subterranean cavities (~1000 caves). Because patterns of spatial and temporal diversity of the bat fauna are virtually unknown in the Caatinga, the main objective of this thesis was to explore the spatial and temporal patterns of richness and species composition of bat assemblages in different landscapes, phytofisiognomies and cave roosts. In Chapter 1, I explored the richness and spatial and temporal diversity in trophic and species composition of bat assemblages through mist-net captures in 5 different Caatinga habitats in six regions throughout RN. In 100 sampling nights, I captured 1575 individuals of 31 species with a net capture effort of 239 824 m2h. Differences in the structure was found at the species- and ensemble-level (trophic guilds) between the assemblages both in the different studied areas and in the different habitats. This is likely related to species specific preferences to favor specific landscape characteristics and foraging habitats. Richness and species composition presented no evident seasonal variation between season. Food resource found along the year may be the key factor that sustain a similar structure of the bat assemblage year-round. In Chapter 2, I monitored nine caves in four regions in RN to examine the effects of the seasons and cave size on the richness and species composition at a roost level. Using two methods we recorded 17 bat species of 2045 captured and 4181 observed individuals in 61 sampling days. Richness and species composition did not change seasonally and no temporal turnover of species was found as well. Yet, increase in overall bat abundance and for some species (insectivores and piscivores) was found mostly in the rainy season. High bat abundance in the rainy season did not coincided with precipitation peaks but an evident abundance decrease coincided with the driest months. A synergy between seasons and cave size was found where in the rainy season large caves tended to vary more in abundance than small caves. As well, differences in species composition was found between large and small caves. Seasonally abundance increase is likely attributed to reproductive purposes. Most of the species were reproductively active during the rainy season where their preferred food was more abundant (frugivores, insectivores and animalivores), while others that rely on year-round available food resources were active during both season (sanguinivores, omnivores and unexpectedly nectarivores). In Chapter 3, I did a taxonomic revision in collections and bibliographic review to determine the gamma diversity of RN and present the first official list of bats of the state, including new records and discussion on conservation and priority research areas. Overall, the data obtained from 44 bat species of 3630 captured individuals and more than 4000 observed bats in 161 sampling days indicates that in general, bat assemblages are adapted to stay year-round in the studied areas but are strongly affected by spatial and by the vegetational structure of their preferred foraging areas. While inside roosts, temporal factors such as food availability strongly affect the reproduction activity of bat assemblages and reinforces the importance of caves of all sizes for the reproduction and protection of Caatingas’ bat populations, including of endemic and vulnerable species. The effort of this thesis, with the key collaboration of many valuable people, is a way to describe and have a deeper insight into the natural history and ecology of the poorly known bat fauna of the seasonal Caatinga dry forest in Brazil
BANKING MEMBERS:
Externo à Instituição - MARLON ZORTÉA - UFG
Presidente - 1718346 - EDUARDO MARTINS VENTICINQUE
Externo à Instituição - ENRICO BERNARD - UFPE
Interno - 1439088 - MAURO PICHORIM
Externa à Instituição - VALERIA DA CUNHA TAVARES - UFPB