Agricultural intensification alters bat assemblage composition and abundance in a dynamic Neotropical landscape

Patterns of Bat Diversity in an Undisturbed Forest and Forest Mosaic Habitats of the Afromontane Forest Biome of Western Cameroon

Anthropogenic activities continue to degrade natural montane ecosystems globally. Bats communities are altered by these changes. We analyzed how bats are affected by human-induced habitat changes by comparing the bat species diversity and functional diversity in undisturbed forest habitats and disturbed forest habitats of the Afromontane biome of Cameroon. We recorded 244 individuals from 13 species in the undisturbed forest, while 233 individuals from 16 species were recorded in the disturbed forest. Bat diversity was higher in disturbed habitats (D = 0.84) than undisturbed habitats (D = 0.67). Jackknife 1 species richness estimator suggests 21.53 species for the disturbed forest and 19.30 in the undisturbed forest. Closed-space forager insectivorous bats made up nearly half of the species in the undisturbed forest, but this dropped to 25% in the disturbed forest, meanwhile, edge-space foragers increased in the disturbed forest. Bat community analyses by ordination revealed a distinct bat community composition between the two forest types, demonstrated as a significant difference in diversity between the two forest types. The distribution of Rousettus aegyptiacus, Myonycteris angolensis, Hipposideros cf. ruber, and Micropteropus pusillus contribute the most to the difference in bat community composition between the two forest types. Edge and open-space species were likely to benefit from additional resources provided by the disturbed area, by expanding their range and distribution. However, this may not compensate for the decline in the population of forest species caused by the loss of pristine forests, thus measures to conserve montane forest remnants should be of utmost significance.

Roosting ecology of insectivorous bats in a tropical agricultural landscape

Bats spend more than half of their life in roosts, where key life events transpire. Therefore the availability and selection of roosts are important to bats everywhere, and may limit their ability to exploit every habitat, including agricultural landscapes such as paddy fields, orchards and tea plantations. This study aimed to investigate the day roosts used by insectivorous bat species in tea plantations of Sri Lanka. We surveyed 18 tea plantations where we recorded a total of 44 roosts involving five families and nine species of bats (Hipposideros galeritus, Hipposideros lankadiva, Hipposideros speoris, Rhinolophus beddomei, Rhinolophus rouxii, Megaderma spasma, Pipistrellus ceylonicus, Pipistrellus coromandra and Miniopterus cf. fuliginosus). Most (26) of the recorded roosts were geomorphic, (11) were anthropogenic, and (7) were in vegetation. H. lankadiva and M. cf. fuliginosus are the only species known to roost exclusively in geomorphic roosts; all others were opportunistic. Although protecting bat roosts is crucial for their conservation, it is challenging in view of existing tea management practices. Therefore, natural roosts should be maintained and protected. The introduction of artificial roosts might increase the number of bats able to forage over tea plantations and maximize their consumption of agricultural pests, thereby increasing tea production.

Landscape structure shapes the diversity of tree seedlings at multiple spatial scales in a fragmented tropical rainforest

The maintenance of seedling diversity of animal-dispersed tree species is fundamental for the structure and function of forest patches in fragmented tropical rainforests. Nonetheless, the effects of landscape structure at different spatial scales on α- and β-diversity of tree seedling communities are recently explored. Using a multi-scale approach, we assessed the relative effect of landscape composition and configuration on α- and β-diversity of animal-dispersed seedlings within 16 forest patches in the Lacandona rainforest, Mexico. We assessed these effects at 13 spatial scales (from 300 to 1500 m radius, at 100 m intervals) for three metrics of effective number of species considering α- and β-diversity. We found that α-diversity was largely affected by landscape composition and β-diversity by landscape configuration. On the one hand, the amount of secondary forest influenced α-diversity. Additionally, species richness increased in landscapes with highly aggregated forest patches. On the other hand, β-diversity was affected positively by forest fragmentation and negatively by the edge contrast of forest patches with the surrounding matrix. Our findings indicate that landscape configuration is a strong driver of seedling diversity in highly deforested rainforests. Promoting forest patches and secondary forests through payment for ecosystem services' programs, favoring matrix quality within land-sharing schemes of smallholder agriculture and secondary forest management, and identifying restoration opportunities for assisted or unassisted natural regeneration are urgently needed for conservation of seedling diversity in human-modified tropical landscapes.

Fragmentation does not affect gene flow in forest populations of the dusky pipistrelle bat on the eastern seaboard of South Africa

The Eastern Cape Province harbors almost half of the indigenous forest in South Africa, but these forests are threatened by large-scale agricultural and urban development planned for the coming decade. Additional anthropogenic development is likely to cause further fragmentation and degradation of forests inhabited by the dusky pipistrelle bat (Pipistrellus hesperidus). We used eight microsatellite markers to study the genetic diversity, population structure, and migration, of P. hesperidus (n = 120) across 14 sites in the Eastern Cape and KwaZulu-Natal provinces of South Africa. We examined the effect of contemporary land cover types on genetic differentiation to assess whether current levels of urbanization and agricultural development affect gene flow. High gene flow and low population structure were evident across sampled sites, apart from genetic discontinuities at the northern (Oribi Gorge Nature Reserve) and southern (Alexandria Forest) ends of the seaboard. Genetic discontinuity at Oribi Gorge may relate to anthropogenic modification of two rivers surrounding the forest, while the Alexandria-linked barrier is a climatic break known as the Bedford gap. Migration rates generally were low between sites except for one Scarp forest, Manubi State Forest, from which individuals dispersed to other sites. The Amatole Mistbelt forests supported high genetic diversity, and likely served as a refugium for P. hesperidus during the Last Glacial Maximum. The composition of land cover classes between sites was a poor predictor of genetic differentiation, although it seems likely that P. hesperidus uses riparian habitats and wetlands for dispersal. Lastly, urban and agricultural development did not have a significant effect on genetic differentiation, which may reflect the wide niche breadth and intermediate distribution range of the species. This study provides insights into genetic diversity and gene flow of P. hesperidus across the study region prior to agricultural intensification and large-scale urbanization.

Dimensions of Phyllostomid Bat Diversity and Assemblage Composition in a Tropical Forest-Agricultural Landscape

Tropical rainforests are suffering rapid habitat loss with large extensions of land transformed into agriculture. We wanted to know whether the type of agricultural activity in forest-agricultural landscapes affects how species composition as well as taxonomic and functional dimensions of diversity respond. We worked in the Amazon forests of southeast Peru and used bats as model organisms. We sampled mosaics characterized by forest adjacent to papaya plantations or cattle pastures. At each sampling site we established a transect in each of the three different vegetation types: forest interior, forest edge and agricultural land. We found that vegetation type was a better predictor of species composition than the type of agricultural land present. Vegetation structure characteristics explained differences in bat species composition between forest interior and edge. Agricultural land type chosen was not irrelevant as we found higher estimated species richness in papaya than in pasture sites. Agricultural land type present in a site and vegetation type affected functional diversity, with both agricultural land types showing a lower number of functionally distinct species than forests. We found papaya plantation sites showed species more evenly dispersed in trait space, suggesting they do better at conserving functional diversity when compared to cattle pasture sites. We demonstrate that sites that harbor agricultural activities can maintain a considerable proportion of the expected bat diversity. We note that this region still has large tracts of intact forest adjacent to agricultural lands, which may explain their ability to maintain relatively high levels bat diversity.

Loss of dominant caterpillar genera in a protected tropical forest

Reports of biodiversity loss have increasingly focused on declines in abundance and diversity of insects, but it is still unclear if substantive insect diversity losses are occurring in intact low-latitude forests. We collected 22 years of plant-caterpillar-parasitoid data in a protected tropical forest and found reductions in the diversity and density of insects that appear to be partly driven by a changing climate and weather anomalies. Results also point to the potential influence of variables not directly measured in this study, including changes in land-use in nearby areas. We report a decline in parasitism that represents a reduction in an important ecosystem service: enemy control of primary consumers. The consequences of these changes are in many cases irreversible and are likely to be mirrored in nearby forests; overall declines in the region will have negative consequences for surrounding agriculture. The decline of important tropical taxa and associated ecosystem function illuminates the consequences of numerous threats to global insect diversity and provides additional impetus for research on tropical diversity.

Misguided policy may jeopardize a diverse South brazilian environmental protection area

Abstract: The Devonian Escarpment (DEEPA), located in the south of Brazil, represents an important area of environmental preservation composed by grasslands, gallery forests, as well as rock outcrops and archaeological sites. A law project (LP 527/2016), which suggests a reduction of the DEEPA area in approximately 70% of its original area (from 393,579 to 125,895 ha), is currently being processed in the Paraná State House of Representatives. Such reduction seems to be related to economic interests (mainly agriculture and mining) in the state of Paraná. If approved, LP 527/2016 will allow farmers to deliberately expand their activities, with the suppression of natural forest as main consequence. Additionally, loss of faunal diversity, contamination of water and soils, and alteration in nutrient cycles are expected, due the intensive use of agrochemicals. In addition to the direct environmental consequences, we expect the disappearance of areas of high geological interest, reducing local geodiversity, as well as substantial economic losses with ecotourism. Brazil is a signatory to the United Nations Convention on Biological Diversity, where it undertakes to develop strategies to prevent biodiversity loss and ecosystem degradation by 2020. An approval of the LP would be contradictory, considering that there are few natural vegetation areas in this region of the country. We emphasize that the proposal of such projects goes against the sustainability in the country and disregard the scientific knowledge generated until then. Thus, it is necessary to develop regional and federal political objectives that guarantee economic development in a balanced way, considering the local bio and geodiversity, not the proposal of mechanisms that destroy them.

Comparative landscape genetics of two frugivorous bats in a biological corridor undergoing agricultural intensification

Agricultural intensification in tropical landscapes poses a new threat to the ability of biological corridors to maintain functional connectivity for native species. We use a landscape genetics approach to evaluate impacts of expanding pineapple plantations on two widespread and abundant frugivorous bats in a biological corridor in Costa Rica. We hypothesize that the larger, more mobile Artibeus jamaicensis will be less impacted by pineapple than the smaller Carollia castanea. In 2012 and 2013, we sampled 735 bats in 26 remnant forest patches surrounded by different proportions of forest, pasture, crops and pineapple. We used 10 microsatellite loci for A. jamaicensis and 16 microsatellite loci for C. castanea to estimate genetic diversity and gene flow. Canonical correspondence analyses indicate that land cover type surrounding patches has no impact on genetic diversity of A. jamaicensis. However, for C. castanea, both percentage forest and pineapple surrounding patches explained a significant proportion of the variation in genetic diversity. Least-cost transect analyses (LCTA) and pairwise G″st suggest that for A. jamaicensis, pineapple is more permeable to gene flow than expected, while as expected, forest is the most permeable land cover for gene flow of C. castanea. For both species, LCTA indicate that development may play a role in inhibiting gene flow. The current study answers the call for landscape genetic research focused on tropical and agricultural landscapes, highlights the value of comparative landscape genetics in biological corridor design and management and is one of the few studies of biological corridors in any ecosystem to implement a genetic approach to test corridor efficacy.