Heard but not seen: Comparing bat assemblages and study methods in a mosaic landscape in the Western Ghats of India

We used capture (mist‐netting) and acoustic methods to compare the species richness, abundance, and composition of a bat assemblage in different habitats in the Western Ghats of India. In the tropics, catching bats has been more commonly used as a survey method than acoustic recordings. In our study, acoustic methods based on recording echolocation calls detected greater bat activity and more species than mist‐netting. However, some species were detected more frequently or exclusively by capture. Ideally, the two methods should be used together to compensate for the biases in each. Using combined capture and acoustic data, we found that protected forests, forest fragments, and shade coffee plantations hosted similar and diverse species assemblages, although some species were recorded more frequently in protected forests. Tea plantations contained very few species from the overall bat assemblage. In riparian habitats, a strip of forested habitat on the river bank improved the habitat for bats compared to rivers with tea planted up to each bank. Our results show that shade coffee plantations are better bat habitat than tea plantations in biodiversity hotspots. However, if tea is to be the dominant land use, forest fragments and riparian corridors can improve the landscape considerably for bats. We encourage coffee growers to retain traditional plantations with mature native trees, rather than reverting to sun grown coffee or coffee shaded by a few species of timber trees.     

Bat activity and species richness in different land‐use types in and around Chome Nature Forest Reserve,Tanzania

Bats have important ecological roles in ecosystems, but many species are threatened because of anthropogenic impacts. Tanzania has limited information on how bats respond to habitat modification. This makes it difficult to anticipate which bat species are at risk. Bat activity and species richness were assessed in five land‐use types: forest and banana–coffee (upland habitats), rice paddy, riverine and sisal estate (lowland habitats). Mist nets, harp traps and bat detectors were used to sample bats. Species richness differed between habitats. Bat activity levels were higher in lowland habitats than upland habitats. Riverine and rice paddy habitats were shown to have an important role as foraging sites for many insectivorous bats as bat species richness and activity were generally higher than other habitats. Fruit‐eating bats preferred riverine and banana–coffee habitats. We recommend using organic manure as alternatives to chemical fertilisers, and pesticide use should be avoided in rice paddies. Riparian vegetation along rivers and water bodies should be maintained as important faunal nesting, roosting and/or foraging grounds. The requirement that farming practices be at least 60 m from the river should be strictly enforced. These recommendations will help in the conservation of bats and their habitats in modified agricultural landscapes.     

Bat and bird diversity along independent gradients of latitude and tree composition in European forests

Species assemblages are shaped by local and continental-scale processes that are seldom investigated together, due to the lack of surveys along independent gradients of latitude and habitat types. Our study investigated changes in the effects of forest composition and structure on bat and bird diversity across Europe. We compared the taxonomic and functional diversity of bat and bird assemblages in 209 mature forest plots spread along gradients of forest composition and vertical structure, replicated in 6 regions spanning from the Mediterranean to the boreal biomes. Species richness and functional evenness of both bat and bird communities were affected by the interactions between latitude and forest composition and structure. Bat and bird species richness increased with broadleaved tree cover in temperate and especially in boreal regions but not in the Mediterranean where they increased with conifer abundance. Bat species richness was lower in forests with smaller trees and denser understorey only in northern regions. Bird species richness was not affected by forest structure. Bird functional evenness increased in younger and denser forests. Bat functional evenness was also influenced by interactions between latitude and understorey structure, increasing in temperate forests but decreasing in the Mediterranean. Covariation between bat and bird abundances also shifted across Europe, from negative in southern forests to positive in northern forests. Our results suggest that community assembly processes in bats and birds of European forests are predominantly driven by abundance and accessibility of feeding resources, i.e., insect prey, and their changes across both forest types and latitudes.     

Biodiversity conservation,yield, and alternative products in coffee agroecosystems in Sumatra,Indonesia

Agroecology and conservation must overlap to protect biodiversity and farmer livelihoods. Coffee agroecosystems with complex shade canopies protect biodiversity. Yet, few have examined biodiversity in coffee agroecosystems in Asia relative to the Americas and many question whether coffee agroecosystems can play a similar role for conservation. We examined vegetation, ant and bird diversity, coffee yields and revenues, and harvest of alternative products in coffee farms and forests in SW Sumatra, Indonesia near Bukit Barisan Selatan National Park (BBS). BBS is among the last habitats for large mammals in Sumatra and >15,000 families illegally cultivate coffee inside of BBS. As a basis for informing management recommendations, we compared the conservation potential and economic outputs from farms inside and outside of BBS. Forests had higher canopy cover, canopy depth, tree height, epiphyte loads, and more emergent trees than coffee farms. Coffee farms inside BBS had more epiphytes and trees and fewer coffee plants than farms outside BBS. Tree, ant, and bird richness was significantly greater in forests than in coffee farms, and richness did not differ in coffee farms inside and outside of BBS. Species similarity of forest and coffee trees, ants, and birds was generally low (<50%). Surprisingly, farms inside the park were significantly older, but farm size, coffee yields, and revenues from coffee did not depend on farm location. Farmers outside BBS received higher prices for their coffee and also more often produced other crops in their coffee fields such that incentives could be created to draw illegal farmers out of the park. We also discuss these results with reference to similar work in Chiapas, Mexico to compare the relative contribution of coffee fields to conservation in the two continents, and discuss implications for working with farmers in Sumatra towards conservation plans incorporating sustainable coffee production.     

Implications of shifts in coffee production on tree species richness, composition and structure on small farms around Mount Kenya

Small coffee farms around Mount Kenya in Kenya contain many planted and remnant tree species but little is known in the region about the relationship between trees on farms and the methods and dynamics of coffee production. Shifts in production may alter tree diversity and potentially impact on future biodiversity conservation efforts by affecting niches available for indigenous trees on farms. Here, knowledge was gathered on how changes in coffee production on 180 small farms around Mount Kenya may affect tree diversity, categorizing farms according to coffee yield levels over a period of five years as increasing, decreasing or stable production. Tree species richness, abundance and composition were analyzed using species accumulation curves, Rènyi diversity profiles, rank abundance and ecological distance ordinations, and the effects of coffee production examined using quasi-Poisson generalized linear regressions. Species richness were positively correlated with tree basal area but negatively related to coffee, banana and maize yields value. A difference in average tree species richness, abundance and basal area on increasing farms was observed compared to the decreasing and stable farms, even though formal tests on richness and densities differences were inconclusive. These dynamics do not significantly influence vegetation structure but seem to have a bearing on species composition on farms of different coffee production. The overall low abundance (23 % of trees) but high richness (78 % of species) of indigenous trees on coffee farms could change markedly if the dynamics observed in the current study persist, indicating the need for the development of intensified multi-species cropping systems.     

Could temperature and water availability drive elevational species richness patterns? A global case study for bats

Aim A global meta‐analysis was used to elucidate a mechanistic understanding of elevational species richness patterns of bats by examining both regional and local climatic factors, spatial constraints, sampling and interpolation. Based on these results, I propose the first climatic model for elevational gradients in species richness, and test it using preliminary bat data for two previously unexamined mountains. Location Global data set of bat species richness along elevational gradients from Old and New World mountains spanning 12.5° S to 38° N latitude. Methods Bat elevational studies were found through an extensive literature search. Use was made only of studies sampling  70% of the elevational gradient without significant sampling biases or strong anthropogenic disturbance. Undersampling and interpolation were explicitly examined with three levels of error analyses. The influence of spatial constraints was tested with a Monte Carlo simulation program, Mid‐Domain Null. Preliminary bat species richness data sets for two test mountains were compiled from specimen records from 12 US museum collections. Results Equal support was found for decreasing species richness with elevation and mid‐elevation peaks. Patterns were robust to substantial amounts of error, and did not appear to be a consequence of spatial constraints. Bat elevational richness patterns were related to local climatic gradients. Species richness was highest where both temperature and water availability were high, and declined as temperature and water availability decreased. Mid‐elevational peaks occurred on mountains with dry, arid bases, and decreasing species richness occurred on mountains with wet, warm bases. A preliminary analysis of bat richness patterns on elevational gradients in western Peru (dry base) and the Olympic Mountains, WA (wet base), supported the predictions of the climate model. Main conclusions The relationship between species richness and combined temperature and water availability may be due to both direct (thermoregulatory constraints) and indirect (food resources) factors. Abundance was positively correlated with species richness, suggesting that bat species richness may also be related to productivity. The climatic model may be applicable to other taxonomic groups with similar ecological constraints, for instance certain bird, insect and amphibian clades.     

Island biogeography of bats in Baja California, Mexico: patterns of bat species richness in a near-shore archipelago

Aim We studied the relationship between the size and isolation of islands and bat species richness in a near‐shore archipelago to determine whether communities of vagile mammals conform to predictions of island biogeography theory. We compared patterns of species richness in two subarchipelagos to determine whether area per se or differences in habitat diversity explain variations in bat species richness. Location Islands in the Gulf of California and adjacent coastal habitats on the Baja California peninsula in northwest Mexico. Methods Presence–absence surveys for bats were conducted on 32 islands in the Gulf of California using acoustic and mist‐net surveys. We sampled for bats in coastal habitats of four regions of the Baja peninsula to characterize the source pool of potential colonizing species. We fitted a semi‐log model of species richness and multiple linear regression and used Akaike information criterion model selection to assess the possible influence of log₁₀ area, isolation, and island group (two subarchipelagos) on the species richness of bats. We compared the species richness of bats on islands with greater vegetation densities in the southern gulf (n = 20) with that on drier islands with less vegetation in the northern gulf (n = 12) to investigate the relationship between habitat diversity and the species richness of bats. Results Twelve species of bats were detected on islands in the Gulf of California, and 15 species were detected in coastal habitats on the Baja peninsula. Bat species richness was related to both area and isolation of islands, and was higher in the southern subarchipelago, which has denser vegetation. Log₁₀ area was positively related to bat species richness, which increased by one species for every 5.4‐fold increase in island area. On average, richness declined by one species per 6.25 km increase in isolation from the Baja peninsula. Main conclusions Our results demonstrate that patterns of bat species richness in a near‐shore archipelago are consistent with patterns predicted by the equilibrium theory of island biogeography. Despite their vagility, bats may be more sensitive to moderate levels of isolation than previously expected in near‐shore archipelagos. Differences in vegetation and habitat xericity appear to be associated with richness of bat communities in this desert ecosystem. Although observed patterns of species richness were consistent with those predicted by the equilibrium theory, similar relationships between species richness and size and isolation of islands may arise from patch‐use decision making by individuals (optimal foraging strategies).     

Instability of copronecrophagous beetle assemblages (Coleoptera: Scarabaeinae) in a mountainous tropical landscape of Mexico

We analyzed changes over time in species composition and functional guild structure (temporal beta diversity) for natural assemblages and those modified by humans in a fragmented, tropical mountain landscape. The assemblages belong to cloud forests (the original vegetation type), secondary forests, traditional shaded coffee plantations, commercial shaded coffee plantations, and a cattle pasture. Copronecrophagous beetles, subfamily Scarabaeinae (Insecta: Coleoptera: Scarabaeidae), were used as the indicator group. This group has been used in previous studies and other tropical forests and has been found to be a good indicator of the effects of anthropogenic change. For each assemblage, we compared samples that were collected several years apart. Changes were found in species composition, order of abundance, and in the proportion that a given species is present in the different functional groups. The changes that occurred between samplings affected the less abundant species in the cloud forest and in the pasture. In the other vegetation types, both abundant and less abundant species were affected. Their order of abundance and proportion in the different guilds also changed. This study shows that, although landscape richness remains relatively constant, richness at the local level (alpha diversity) changes notably even over short lapses of time. This could be a characteristic of landscapes with intermediate degrees of disturbance (such as those that have been partially modified for human use), where assemblage composition is very fluid.     

Bat species diversity and distribution in a disturbed regime at the Lake Bogoria National Reserve,Kenya

Human population growth drives intrusion and progressive conversion of natural habitats for agriculture. We evaluated human impacts on bat species diversity and distribution among four vegetation types in and around Lake Bogoria National Reserve between November 2012 and July 2013. Plants were surveyed using the Braun–Blanquet cover/abundance method, whereas bats were sampled using standard mist nets erected on poles at ground level. Floristic similarity analysis revealed three broad vegetation assemblages, namely riverine vegetation, farmland and Acacia woodland/Acacia–Commiphora woodland. Two hundred and 33 bats representing eleven species in eleven genera and seven families were recorded. These were Epomophorus minimus, Rhinolophus landeri, Hipposideros caffer, Cardioderma cor, Lavia frons, Nycteris hispida, Chaerephon pumilus, Mops condylurus, Neoromicia capensis, Scotoecus hirundo and Scotophilus dinganii. Species richness estimators indicated that sampling for bats at ground level was exhaustive. Bat species richness and diversity were highest in the more structurally complex Acacia woodland compared to more homogenous farmlands where we recorded only common and generalist species that often occur in open habitats. The higher bat species richness and diversity in the Acacia woodland as compared to farmland underscore the importance of remnant natural savannah woodlands in the conservation of bats and other elements of biodiversity .     

What Factors Affect Diversity and Species Composition of Endangered Tumbesian Dry Forests in Southern Ecuador?

This paper reports a study on species richness and composition of Tumbesian dry forest communities. We tested two alternative hypotheses about species assemblage processes in tropical dry forests: (1) species assemblage is determined by the filtering effect of environmental conditions and (2) species assemblage is determined by facilitative processes along the gradient of water availability, and thus, species richness and evenness increase as water becomes limited. In addition, we also explored the effect of climate and soil conditions on species composition in tropical dry forests. Species composition was sampled in 109 plots in terms of cover and tree diameter at breast height. Climatic, edaphic, topographic and anthropogenic degradation variables were obtained for each plot. We used generalized linear models and canonical correspondence analyses to evaluate the effect of environmental variables on species composition, richness and evenness. Water availability negatively affected richness and significantly determined the species assemblage. Species richness increased from ridges to valleys and evenness increased at higher altitudes. Soil characteristics showed no effect on richness and evenness but soil moisture, nitrogen concentration and soil temperature explained significant fractions of species composition. Although timber extraction and livestock in our study area were of low intensity, it negatively affected richness but had only a minor effect on species composition. Our results suggest that species composition in these endangered tropical dry forests may be at least partially explained by the stress‐gradient hypothesis, with higher species richness at drier conditions probably induced by facilitation processes.     

Bats are Not Birds – Different Responses to Human Land‐use on a Tropical Mountain

Land‐use intensification has consequences for biodiversity and ecosystem functioning, with various taxonomic groups differing widely in their sensitivity. As land‐use intensification alters habitat structure and resource availability, both factors may contribute to explaining differences in animal species diversity. Within the local animal assemblages the flying vertebrates, bats and birds, provide important and partly complementary ecosystem functions. We tested how bats and birds respond to land‐use intensification and compared abundance, species richness, and community composition across a land‐use gradient including forest, traditional agroforests (home garden), coffee plantations and grasslands on Mount Kilimanjaro, Tanzania. Furthermore, we asked how sensitive different habitat and feeding guilds of bats and birds react to land‐use intensification and the associated alterations in vegetation structure and food resource availability. In contrast to our expectations, land‐use intensification had no negative effect on species richness and abundance of all birds and bats. However, some habitat and feeding guilds, in particular forest specialist and frugivorous birds, were highly sensitive to land‐use intensification. Although the habitat guilds of both, birds and bats, depended on a certain degree of vegetation structure, total bat and bird abundance was mediated primarily by the availability of the respective food resources. Even though the highly structured southern slopes of Mount Kilimanjaro are able to maintain diverse bat and bird assemblages, the sensitivity of avian forest specialists against land‐use intensification and the dependence of the bat and bird habitat guilds on a certain vegetation structure demonstrate that conservation plans should place special emphasis on these guilds.     

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

The recent trend of agricultural intensification in tropical landscapes poses a new threat to biodiversity conservation. Conversion of previously heterogeneous agricultural landscapes to intensive plantation agriculture simplifies and homogenizes the landscape, reducing availability, and connectivity of natural habitat for native species. To assess the impact of agricultural intensification on bats, we characterized the bat assemblage in the Sarapiquí region of Costa Rica, where heterogeneous land uses are being converted to intensive, large‐scale pineapple plantations. In 2012 and 2013, we sampled bats in 20 remnant forest patches surrounded by varying proportions of pasture, mature forest, and pineapple and captured 1821 individual bats representing 39 species. We used ordination analyses to evaluate changes in species composition, where pineapple is the main component of the agricultural matrix. We identified landscape metrics specifically correlated with pineapple and used multiple linear regression to test their effects on bat species richness, diversity, and guild‐specific relative abundance. Results suggest pineapple expansion is driving changes in assemblage composition in remnant forest patches, resulting in new assemblages with higher proportions of frugivorous bats and lower proportions of insectivorous bats than in continuous mature forests. In addition, while pineapple does not diminish total bat species richness and diversity, the reduced forest cover and increased distance between forest patches in pineapple plantations has a significant negative impact on the relative abundance of insectivores. We also identify a potential threshold effect whereby patches surrounded by more than 50 percent forest can retain assemblage composition similar to that found in continuous mature forest.     

Invasion and retreat: shifting assemblages of dung beetles amidst changing agricultural landscapes in central Peru

This study examines the effects of deforestation, and the habitat value of coffee and regenerated forest for tropical dung beetles, a functionally significant insect group. Pitfall trapping was conducted at 22 sites in a montane region of central Peru during April and November/December of 2002. Sites included primary and secondary forest, shade-coffee, regenerated forest and open farms (mainly with banana, yuca, and corn). Ordination techniques indicated that beetle assemblages in forests, regenerated forest and coffee were relatively similar. However, assemblage compositions in forested areas differed even at similar altitudes under the influence of biogeographical factors, and the assemblages at disturbed sites (farms/coffee) were influenced by beetle dispersal from adjacent forests. During dry months, when beetle activity is low, communities at all habitat types tended to converge because fewer unique species were recorded in forests at that time and habitat/season generalists were dominant. Preliminary results also indicate that beetles in shady crops such as bananas responded to plant growth: as the banana canopy closed-in, producing more shade, open-habitat specialists retreated and forest/shade specialists invaded the sites. Chronosequence data at two of the sites demonstrate the rapid and dramatic changes in species richness and assemblage composition caused by deforestation. As forests become increasingly fragmented, and open farms continue to expand, dung beetles will become more restricted to the remaining fragments and reserves. In the mosaic landscape studied here, shade crops, like coffee, act as habitat and corridors for many dung beetle species. Small farm size and the consequent magnitude of edge effects, likely contributed to beetle movement between habitat types and determined the apparent generalist nature of many of the dung beetle species in this study.     

Recovery of Amphibian and Reptile Assemblages During Old‐Field Succession of Tropical Rain Forests

Conversion of tropical forests to agriculture affects vertebrate assemblages, but we do not know how fast or to what extent these assemblages recover after field abandonment. We addressed this question by examining amphibians and reptiles in secondary forests in southeastern Mexico. We used chronosequence data (12 secondary forests fallow for 1–23 yr and 3 old‐growth forest sites) to analyze successional trajectories and estimate recovery times of assemblage attributes for amphibians and reptiles. We conducted 6 surveys at each site over 14 mo (1200 person‐hours) and recorded 1552 individuals, including 25 species of amphibians and 36 of reptiles, representing 96 and 74 percent of the expected regional number of species, respectively. Abundance, species richness, and species diversity of amphibians increased rapidly with successional age, approaching old‐growth forest values in < 30 yr. Species richness and species diversity of reptiles reached old‐growth forest values in < 20 yr. By contrast, the abundance of reptiles and the assemblage composition of amphibians and reptiles recovered more slowly. Along the chronosequence, we observed more species replacement in reptile assemblages than in amphibian assemblages. Several species in the old‐growth forest were absent from secondary forests. Dispersal limitation and harsh conditions prevailing in open sites and early successional environments appear to preclude colonization by old‐growth forest species. Furthermore, short fallow periods and isolation of forest remnants lead to the formation of new assemblages dominated by species favored by human disturbances.     

Ecological biogeography of Mexican bats: the relative contributions of habitat heterogeneity,beta diversity,and environmental gradients to species richness and composition patterns

Mexico has higher mammalian diversity than expected for its size and geographic position. High environmental hetero geneity throughout Mexico is hypothesized to promote high turnover rates (β‐diversity), thus contributing more to observed species richness and composition than within‐habitat (α) diversity. This is true if species are strongly associated with their environments, such that changes in environmental attributes will result in changes in species composition. Also, greater heterogeneity in an area will result in greater species richness. This hypothesis has been deemed false for bats, as their ability to fly would reduce opportunities for habitat specialization. If so, we would expect no significant relationships between 1) species composition and environmental variables, 2) species richness and environmental heterogeneity, 3) β‐diversity and environmental heterogeneity. We tested these predictions using 31 bat assemblages distributed across Mexico. Using variance partitioning we evaluated the relative contribution of vegetation, climate, elevation, horizontal heterogeneity (a variate including vegetation, climate, and elevational heterogeneity), spatial variation (lat‐long), and vertical hetero geneity (of vegetation strata) to variation in bat species composition and richness. Variation in vegetation explained 92% of the variation in species composition and was correlated with all other variables examined, indicating that bats respond directly to habitat composition and structure. Beta‐diversity and vegetational heterogeneity were significantly correlated. Bat species richness was significantly correlated with vertical, but not horizontal, heterogeneity. Nonetheless, neither horizontal nor vertical heterogeneity were random; both were related to latitude and to elevation. Variation in bat community composition and richness in Mexico were primarily explained by local landscape heterogeneity and environmental factors. Significant relationships between β‐diversity and environmental variation reveal differences in habitat specialization by bats, and explain their high diversity in Mexico. Understanding mechanisms acting along environmental or geographic gradients is as important for understanding spatial variation in community composition as studying mechanisms that operate at local scales.     

Relationship between topographic heterogeneity and vegetation patterns in a Californian salt marsh

Questions: Are species richness and species abundances higher in the presence of tidal creeks? Do species richness and species abundances vary with plot size? Location: Intertidal plain of Volcano Marsh, Bahia de San Quintin, Mexico. Methods: We analysed vegetation patterns in large areas (cells) with tidal creeks (+creek) and without (‐creek). We surveyed vegetation cover, microtopography, habitat type, and distance to creeks in nested plots of five sizes, 0.1, 0.25, 1, 2.5, and 10 m². Results: Species richness, frequency, cover, and assemblages differed between ±creek cells. Richness tended to be higher in +creek cells, and cover and frequency of individual species differed significantly between ±creek cells. We found consistent patterns in vegetation structure across plot sizes. We encountered 13 species that occurred in 188 unique assemblages. The most common assemblage had six species: Batis maritima, Frankenia salina, Salicornia bigelovii, S. virginica, Salicornia spec. and Triglochin concinna. This assemblage occurred in ±creek cells and at all spatial scales. Of the most common assemblages all but one were composed of multiple species (3–9 species/plot). Conclusions: The persistence of vegetation patterns across a 100‐fold range in spatial scale suggests that similar environmental factors operate broadly to determine species establishment and persistence. Differences in assemblage composition result from variation of frequency and cover of marsh plain species, particularly Suaeda esteroa and Monanthochloe littoralis. The recommendation for restoration of Californian salt marshes is to target (and plant) multi‐species assemblages, not monocultures.     

Tropical Secondary Forest Management Influences Frugivorous Bat Composition,Abundance and Fruit Consumption in Chiapas,Mexico

Most studies on frugivorous bat assemblages in secondary forests have concentrated on differences among successional stages, and have disregarded the effect of forest management. Secondary forest management practices alter the vegetation structure and fruit availability, important factors associated with differences in frugivorous bat assemblage structure, and fruit consumption and can therefore modify forest succession. Our objective was to elucidate factors (forest structural variables and fruit availability) determining bat diversity, abundance, composition and species-specific abundance of bats in (i) secondary forests managed by Lacandon farmers dominated by Ochroma pyramidale, in (ii) secondary forests without management, and in (iii) mature rain forests in Chiapas, Southern Mexico. Frugivorous bat species diversity (Shannon H’) was similar between forest types. However, bat abundance was highest in rain forest and O. pyramidale forests. Bat species composition was different among forest types with more Carollia sowelli and Sturnira lilium captures in O. pyramidale forests. Overall, bat fruit consumption was dominated by early-successional shrubs, highest late-successional fruit consumption was found in rain forests and more bats consumed early-successional shrub fruits in O. pyramidale forests. Ochroma pyramidale forests presented a higher canopy openness, tree height, lower tree density and diversity of fruit than secondary forests. Tree density and canopy openness were negatively correlated with bat species diversity and bat abundance, but bat abundance increased with fruit abundance and tree height. Hence, secondary forest management alters forests’ structural characteristics and resource availability, and shapes the frugivorous bat community structure, and thereby the fruit consumption by bats.     

Do riparian forest strips in modified forest landscapes aid in conserving bat diversity?

Agricultural practices lead to losses of natural resources and biodiversity. Maintaining forests alongside streams (riparian forest strips) has been used as a mechanism to minimize the impact of clearing for agriculture on biodiversity. To test the contribution of riparian forest strips to conserve biodiversity in production landscapes, we selected bats as a biodiversity model system and examined two dimensions of diversity: taxonomic and functional. We compared bat diversity and composition in forest, with and without stream habitat, and in narrow forest riparian strips surrounded by areas cleared for agriculture. We tested the hypothesis that riparian forest strips provide potential conservation value by providing habitat and serving as movement corridors for forest bat species. Riparian forest strips maintained 75% of the bat species registered in forested habitats. We found assemblage in sites with riparian forest strips were dominated by a few species with high abundance and included several species with low abundance. Bat species assemblage was more similar between sites with streams than between those sites to forests without stream habitat. These results highlight the importance of stream habitat in predicting presence of bat species. We registered similar number of guilds between forest sites and riparian forest strips sites. Relative to matrix habitats, stream and edge habitats in riparian forest strips sites were functionally more diverse, supporting our hypothesis about the potential conservation value of riparian forest strips. Results from this study suggest that maintaining riparian forest strips within cleared areas for agricultural areas helps conserve the taxonomic and functional diversity of bats. Also, it provides basic data to evaluate the efficacy of maintaining these landscape features for mitigating impacts of agricultural development on biodiversity. However, we caution that riparian forest strips alone are not sufficient for biodiversity maintenance; their value depends on maintenance of larger forest areas in their vicinity.     

Wild coffee management and plant diversity in the montane rainforest of southwestern Ethiopia

Coffea arabica occurs naturally in the montane rainforests of Ethiopia, but large areas of these unique forests have been converted to other land-uses. In the remaining forest, wild coffee is managed and harvested with increasing intensity because of rising coffee prices in the world market. This study evaluated the impact of coffee management on wild coffee populations and the forest vegetation as a basis for conservation planning in southwestern Ethiopia. Vegetation surveys and yield assessments were carried out in unmanaged natural forest and in managed semi-forest coffee (SFC) systems. Analyses show that wild coffee density and coffee yields were low in natural forest (max. 15 kg ha⁻¹ year⁻¹). In SFC systems, 30% of the canopy trees and most undergrowth vegetation were removed. This stimulated wild coffee growth and strongly enhanced yields (max. 54 kg ha⁻¹ year⁻¹), but severely disturbed forest structure. Species richness increased by 26% because of an increase in species of ruderal and secondary vegetation; however, species richness and abundance of typical forest species declined. Conservation of the natural forest therefore requires the control of wild coffee management. Wild coffee certification is discussed as one tool to reconcile conservation measures and the interests of local farmers.     

Ecological characterization of bat species distributions in Michoacán, México, using a geographic information system

Aim To investigate the relationship between chiropteran species distributions and four fundamental environmental factors — temperature, precipitation, soil and vegetation — and to construct a species richness prediction map based on the environmental factors. Location The state of Michoacán, México. Methods Bat specimens collected during a 2‐year project were combined with museum specimens to form a dataset of over 3200 entries pertaining to 71 species of bats. Coordinates of the collection localities were recorded with GPS receivers or determined from maps. ArcView GIS was used to characterize the distribution of the species relative to the four environmental factors by projecting coordinates of the collection sites onto digitized maps of those factors. Correspondence analysis (CA) was used to evaluate the relationship between species distributions and the environmental factors. Results The CA results indicated that the order of importance of these factors is (from highest to lowest): temperature, vegetation, precipitation and soil. A predicted distribution map was constructed for each species of bat, based on the result of the CA analysis, using correspondences of each species to climate, vegetation and precipitation. Soil types were excluded from the prediction model because soil type does not appear to carry high predictive value for bat species in Michoacán. Distribution maps of the 71 bat species were then overlaid to generate a map of bat species richness for the state of Michoacán. Main conclusions Neither family membership nor feeding guild affiliation appear to play important roles in chiropteran species distributions in Michoacán. The bat species richness prediction map will be a useful tool for conservation works in the region.