The overall objective of this research project is to establish a baseline to monitor ecological and cultural changes in Sibiloi National Park, while controlling for changes in the surroundings. Because of the notorious lack of comprehensive sources with which to assess change in the area, the establishment of a baseline remains paramount in order to monitor both current and future threats, as well as to provide the required information to optimize conservation efforts both within and outside the park, working together with the local communities.
Researchers: Mar Cabeza, Daniel Burgas, Ricardo Rocha, Álvaro Fernández-Llamazares, Sara Fraixedas & Adrià López-Baucells
Turkana Basin Institute (TBI)
Although a growing number of studies have addressed the effects of forest fragmentation on tropical bat assemblages, these studies generally have had to draw inferences based on sampling that spanned relatively short periods. However, little is known about bat responses to habitat fragmentation over the longer term.
Most of our empirical understanding of tropical fragmentation has been derived from the Biological Dynamics of Forest Fragments Project (BDFFP) in Brazil, the world’s largest and longest-running experimental study of habitat fragmentation. The impacts of forest fragmentation on the BDFFP bat fauna were initially assessed in 1996-99. The overall objective of this project is to investigate the temporal dynamics of bat responses to forest fragmentation within the BDFFP landscape. The availability of a data set from 1996-99 provided an unique opportunity for a comparative follow-up study aimed at elucidating temporal changes in the bat fauna and therefore to provide rare insights into the longer-term dynamics of a fragmented tropical bat assemblage.
We are currently resurveying the same forest fragments and control plots in continuous forest first surveyed in 1996-99 (using identical methods, i.e. ground and canopy mist nets for sampling phyllostomid bats and automatic and manual acoustic surveys for aerial insectivorous bats). These data will be used to evaluate temporal changes in population- (abundance), ensemble-, and assemblage-level parameters (e.g. species richness, diversity, species composition) and how they differ among fragments of different size and between fragments and controls.
Little is known about how bats respond to edge effects, particularly in relation to temporal changes in the strength of edge effects associated with matrix regeneration. Data from interior and edge transects in the fragments and controls as well as in the adjoining matrix will be used to assess edge-related responses of bats and to determine temporal variation in those responses.
As fragmentation is a landscape-scale phenomenon, the consequences of fragmentation on biodiversity are most appropriately assessed within a landscape framework. We will determine fragmentation effects within the greater landscape context and assess whether bat responses are related to a range of predictors describing landscape composition and configuration. By evaluating relationships between biotic response variables and landscape metrics both across different spatial scales and across time we will be able to more adequately address the complexity underlying bat responses to fragmentation than in previous studies on this issue.
We will further evaluate whether species responses are associated with particular ecological traits of bat species. Comparing the results with findings from a study in a landbridge island system will allow us to gain insights into which species characteristics determine vulnerability to landscape transformation in systems of different fragment-matrix contrast. So far no study evaluating fragmentation impacts on bats has addressed both the spatial aspects of fragmentation, i.e. the larger landscape context, and temporal effects, as we propose to do. We believe that this approach can greatly advance our understanding of fragmentation effects on bats and that the findings from this study will make an important contribution to the field of fragmentation research in general.
Ferreira, D., Rocha, R., López-Baucells, A., Farneda, F.Z., Carreiras, J.M.B, Palmeirim, J.M. & Meyer, C.F.J. Season-modulated responses of Neotropical bats to forest fragmentation. Ecology and Evolution,in review.
Rocha, R., López-Baucells, A., Farneda, F.Z., Groenenberg, M., Bobrowiec. P.E.D., Cabeza, M., Palmeirim, J.M. & Meyer, C.F.J. Consequences of a large-scale fragmentation experiment on Neotropical bats: disentangling the relative effects of local and landscape-scale attributes. Landscape Ecology, in press.
Rocha, R., Gordo, M., & López-Baucells, A. (2016) Completing the menu: addition of Sinax ruber and Dendropsophus minutus (Anura: Hylidae) to the diet of Trachops cirrhosus (Chiroptera: Phyllostomidae) in Central Amazon. North-Western Journal of Zoology, 12(1): 199-201.
Farneda, F.Z., Rocha, R., López-Baucells, A., Groenenberg, M., Silva, I., Palmeirim, J.M., Bobrowiec. P.E.D. & Meyer, C.F.J. (2015) Trait-related responses to habitat fragmentation in Amazonian bats. Journal of Applied Ecology, 52(5): 1381-1391.
López-Baucells, A., Rocha, R., Fernández-Arellano, G., Bobrowiec. P.E.D., Palmeirim, J.M. & Meyer. C.F.J. (2014) Echolocation of the Big Red Bat Lasiurus egregius (Chiroptera: Vespertilionidae) and first record from the Central Brazilian Amazon. Studies on Neotropical Fauna and Environment, 49(1):18-25
López-Baucells, A., Rocha, R., Mayés, I., Vulinec, K. & Meyer. C.F.J. (2013) First record of Micronycteris sanborni (Chiroptera: Phyllostomidae) from Central Amazonia, Brazil: range expansion and description of its echolocation. Mammalia, 78(1): 127–132
Madagascar is almost unmatched in its levels of endemism and species diversity leading to its classification as one of the highest priorities for international conservation. Most of the island’s endemics are exclusive to forest ecosystems and are currently threatened by severe rates of forest loss.
Despite its proximity to the African continent, humans only reached the island some 2,000 years ago. Human arrival was followed by the extinction of most of the islands’ megafauna and by a major change in forest cover. In recent decades deforestation has continued apace, and in just half a century (c. 1953 to c. 2000), the island’s total forested area decreased by nearly 40% causing several recent faunal extinctions. Nowadays, Madagascar is in the midst of severe land-use change, mostly driven by slash-and-burn, smallholder agriculture. Understanding the consequences of these agricultural practices for Malagasy native species is therefore of the foremost importance for the conservation of the nation’s biodiversity.
We investigate how Malagasy bird and bat assemblages are capable to persist across the island’s anthropocentric habitats. We’re also trying to understand the potential of insectivorous bats to suppress populations of agricultural insect pests.
Eklund, J., Blanchet, G., Nyman, J., Rocha, R., Virtanen, T. & Cabeza, M. Contrasting spatial and temporal trends of protected area effectiveness in mitigating deforestation in Madagascar. Biological Conservation, in review.
López-Baucells, A., Rocha, R., Andriatafika, Z., Tojosoa, T., Kemp, J., Forbes, K., Cabeza, M. Roost selection by synanthropic bats in rural Madagascar: what makes non-traditional structures so tempting? Hystrix, in review.
Rocha, R., Tarmo, V. & Cabeza, M. (2015) Bird assemblages in a Malagasy forest-agricultural frontier: effects of habitat structure and landscape-scale forest cover. Tropical Conservation Science, 8(3): 681-710.
Among the four species of flying foxes found in Australia, Pteropus alecto is extending its distribution colonizing new territories in the southern becoming sympatric with the native and endangered Pteropus poliocephalus at the edges of its distribution. In 2010, severe starvation conditions and food shortage in the Sydney region resulted in considerable mortality and morbidity of flying-foxes. This recent colonization event together with the limiting food availability offered a suitable scenario to study one of the first phases of the aforementioned competition relationships between sibling species, and model it by comparing food usage with stress condition.
A very clear partitioning process on feeding resources, characterized by plant species turnover in the diet was revealed. While fruit was the most frequent food type for both bat species, native Ficus sp. was the main item in P. poliocephalus but exotic palm’s fruits were mainly found in P. Alecto. Pollen evidences were, in both species always at lower proportions. Although high stress hormone levels were detected overall, they were weakly influenced by diet composition. We proved how ecosystems with introduced species could definitely lead to additional invasions as a reciprocal partitioning facilitation process, as shown in our case study, where the exotic palms might most likely have facilitated the recent P. alecto establishment. We provide evidence that stress condition assessment in wild bats can be successfully used in order to quantify general stress within the colonies and monitor it through time, but it might be difficult to use in order to unravel interspecific competition.
López-Baucells, A., Parry-Jones, K., Webster, K. N., Divljan, A., Garin, I. Sharing or shifting? Exploring the effects of severe starvation conditions on feeding competition between flying foxes. In preparation.
The islands of São Tomé and Príncipe in the Gulf of Guinea island system are known as being an exceptional centre of endemism and have a five century long history of agricultural induced habitat modification with much of it being steered by cocoa and coffee shade plantations. Despite this, many of the endemics have been able to adapt to the agricultural landscapes with considerable tree cover associated with shade plantations and no extinctions of endemic species have been documented on the island. In the last decades however, a shift from agroforestry systems to more open agricultural practices involving less tree cover has started to take place and the impacts of this land-use transformation in the island native species is still largely unknown.
Assessing the relative impact of different agricultural practices is therefore essential to design conservation strategies which can best preserve the islands biodiversity while satisfying human needs.
Carvalho, M., Rego, F. Palmeirim, J. & Fa. J.E. (2015) Wild meat consumption on São Tomé Island, West Africa: implications for conservation and local livelihoods. Ecology and Society, 20(3), 27.
Carvalho, M., Palmeirim, J.M., Rego, F.C., Sole, N., Santana, A. & Fa., J.E. (2015) What motivates hunters to target exotic or endemic species on the island of São Tomé, Gulf of Guinea? Oryx, 49, 278-286.
Russo, D., Maglio, G., Rainho, A., Meyer, C.F.J., Palmeirim, J. (2011) Out of the dark: diurnal activity in the bat Hipposideros ruber on São Tomé island (West Africa). Mammalian Biology, 76, 701-708.