Settling Decisions and Heterospecific Social Information Use in Shrikes

Animals often settle near competitors, a behavior known as social attraction, which belies standard habitat selection theory. Two hypotheses account for these observations: individuals obtain Allee benefits mediated by the physical presence of a competitor, or they use successfully settled individual as a source of information indicating the location of high quality habitat. We evaluated these hypotheses experimentally in two species of shrikes. These passerine birds with a raptor-like mode of life impale prey to create larders that serve as an indicator of male/habitat quality. Thus, two forms of indirect information are available in our system: a successfully settled shrike and its larder. Typically these two cues are associated with each other, however, our experimental treatment created an unnatural situation by disassociating them. We manipulated the presence of larders of great grey shrikes and examined the settling decisions of red-backed shrikes within and outside the great grey shrike territories. Male red-backed shrikes did not settle sooner on plots with great grey shrikes compared to plots that only contained artificial larders indicating that red-backed shrikes do not use the physical presence of a great grey shrike when making settling decisions which is inconsistent with the Allee effect hypothesis. In contrast, for all plots without great grey shrikes, red-backed shrikes settled, paired and laid clutches sooner on plots with larders compared to plots without larders. We conclude that red-backed shrikes use larders of great grey shrikes as a cue to rapidly assess habitat quality.     

Progressive bias in species status is symptomatic of fine-grained mapping units subject to repeated sampling

Atlas maps of butterflies invariably fail to distinguish the status of records, that is, whether they are observations of breeding populations or vagrant individuals. Yet, for conservation purposes, it is clearly important to know whether records relate to breeding populations in suitable habitats or not. The high mobility of butterfly adults carries two expectations. First, vagrants will frequently be recorded within grid squares, particularly when mapping is fine grained. Second, the frequency of vagrants is likely to be higher in mapping units comprising biotopes with few butterfly habitats, than in those rich in butterfly habitats, if only because there is a greater regional pool of potential vagrants for biotopes depleted in butterfly habitats. It follows that with repeated sampling of squares or biotopes differences in species breeding status will be cumulative between those rich and poor in butterfly habitats. In this paper, these predictions have been tested using data from 30, 1 ha grid squares on Alderley Edge Site of Special Scientific Interest (SSSI) (UK), half of which are in woodland (few butterfly habitats) and half with open habitats (non-woodland; rich in butterfly habitats). Butterflies have been recorded during 38 visits over 4 years. Within squares, vagrants have been distinguished from breeding species on the basis of the presence of larval hostplants and other suitable resources for seasonal maintenance. Owing to the occurrence of vagrants, number of breeding species was found to be significantly fewer than total species in mapping units. Vagrants were found to be significantly more abundant in woodland squares, which contain few species larval hostplants, than in squares dominated by open biotopes with many species larval hostplants. Repeated sampling resulted in a cumulative increase in the frequency of vagrant species. Furthermore, the relative frequency of vagrants increased at a greater rate in woodland squares compared to non-woodland squares. Suggestions are made as to how recording for atlases may be improved.     

Adaptive plasticity in wing melanisation of a montane butterfly across a Himalayan elevational gradient

1. Traits that are significant to the thermal ecology of temperate or montane species are expected to prominently co-vary with the thermal environment experienced by an organism. The Himalayan Pieris canidia butterfly exhibits considerable variation in wing melanisation. We investigated: (i) whether variation in wing melanisation and (ii) activity period of this montane butterfly was influenced by the seasonally and elevationally changing thermal landscape.
2. We discovered that wing melanisation varied across elevation, seasons, sex, and wing surfaces, with the variation strongly structured in space and time: colder seasons and higher elevations produced more melanic individuals. Notably, melanisation did not vary uniformly across all wing surfaces: (i) melanisation of the ventral hindwing co-varied much more prominently with elevation, but (ii) melanisation on all other surfaces varied with seasonal changes in the thermal environment.
3. Observed wing surface-specific patterns indicated thermoregulatory function for this variation in melanisation. Such wing surface-specific responses to seasonal and elevational variation in temperature have rarely been reported in montane insects.
4. Moreover, daily and seasonal thermal cycles were found to strongly influence activity periods of this species, suggesting the potential limits to wing melanisation plasticity.
5. Overall, these results showed that the seasonal and elevational gradients in temperature influence the thermal phenotype as well as activity periods of this Himalayan butterfly. It will be critical to study the phenotypic evolution of such montane insects in response to the ongoing climate change, which is already showing significant signs in this iconic mountain range.

     

Species-specific engineered antifouling topographies: correlations between the settlement of algal zoospores and barnacle cyprids

Novel, non-toxic antifouling technologies are focused on the manipulation of surface topography to deter settlement of the dispersal stages of fouling organisms. This study investigated the effect of the aspect ratio (feature height/feature width) of topographical features engineered in polydimethylsiloxane, on the settlement of cyprids of Balanus amphitrite and zoospores of Ulva linza. The correlation of relative aspect ratios to antifouling efficacy was proven to be significant. An increase in aspect ratio resulted in an increase of fouling deterrence for both zoospores and cyprids. The spore density of Ulva was reduced 42% with each unit increase in aspect ratio of the Ulva-specific Sharklet AF topography. Similarly, the number of settled cyprids was reduced 45% with each unit increase in aspect ratio. The newly described barnacle-specific Sharklet AF topography (40 microm feature height, aspect ratio of 2) reduced cyprid settled by 97%. Techniques have been developed to superimpose the smaller Ulva-specific topographies onto the barnacle-specific surfaces into a hierarchical structure to repel both organisms simultaneously. The results for spore settlement on first-generation hierarchical surfaces provide insight for the efficacious design of such structures when targeting multiple settling species.     

Targeting squares for survey: predicting species richness and incidence of species for a butterfly atlas

1. Predictions on species richness and incidence of species are made using data for three scales of mapping from the Greater Manchester butterfly atlas; for the whole of the conurbation (2 km×2 km scale) and for two sample areas centred on the Mersey Valley (1 km×1 km scale; 1 ha scale). Predictions are based on data for recording effort, altitude, biotopes, host-plants and nectar resources. 2. Data for Greater Manchester indicate that substantial shortfalls may occur in recording butterfly species for atlases despite the fact that butterflies are generally easily identified and well supported with recorders. Shortfalls tend to be larger for species with fewer records, indicating that some species may be more easily overlooked than others. 3. The results demonstrate that targeting squares for re-survey is necessary and feasible. The predictions have other valuable research applications, the most important of which is being able to assess the accuracy of distribution maps, to correct them, and to make projections of distribution changes. 4. Predictions may be enhanced by improvements to mapping in three ways: (i) Collecting data on recording effort. Variation in recording effort typically accounts for differences in species richness and incidence of species more than any other variable; (ii) Collecting data on biotopes and specific resources. The present results are promising and demonstrate that the collection of environmental data linked to a suitable sampling frame could facilitate knowledge of the distribution of species over extensive areas that remain under-recorded; and (iii) Distinguishing between breeding individuals and vagrants. Vagrancy is a problem associated both with species and scale. Although species vary substantially in their capacity to migrate beyond their habitats, the effect of vagrancy on distribution maps becomes an increasingly large problem as the grain of mapping (size of recording units) decreases. It is suggested that over-recording can be a problem, particularly when mapping is fine-grained.     

Ecological Restoration Treatments Increase Butterfly Richness and Abundance: Mechanisms of Response

Few ecosystem restoration studies evaluate whether arthropods are important components of ecosystem recovery. We tested the hypothesis that ponderosa pine restoration treatments would increase adult butterfly species richness and abundance as a direct result of increased understory diversity and abundance. To examine mechanisms that potentially affect adult butterfly distribution, we quantified host plant frequency, nectar plant abundance, and insolation (light intensity) in restoration treatment and control forests. This study is unique, because this is the first invertebrate monitoring in ponderosa pine forest restoration treatments in the U.S. Southwest and also because these treatments are the first replicated ponderosa pine restoration treatments at a landscape scale. Three patterns emerged: (1) butterfly species richness and abundance were 2 and 3 times greater, respectively, in restoration treatment units than in paired control forests 1 year after treatment, and 1.5 and 3.5 times greater, respectively, 2 years after treatment, ordination of control and treatment sampling units using butterfly assemblages showed significant separation of control and restoration treatment units after restoration treatment; (2) host plant and nectar plant species richness showed little difference between treated and control forests even 2 years after treatment; and (3) insolation (light intensity) was significantly greater in treated forests after restoration. We suggest that changes in the butterfly assemblage may occur due to light intensity effects before plant community changes occur or can be detected. Butterfly assemblage differences will have additional cascading effects on the ecosystem as prey for higher trophic levels and through plant interactions including herbivory and pollination.     

Poly modal emergence of the tiger swallowtail, Papilio glaucus (Lepidoptera: Papilionidae): source of a false second generation in central New York State

Abstract. 1. The tiger swallowtail butterfly, Papilio glaucus (L.) (Lepidoptera: Papilionidae), is commonly assumed to have a bivoltine life cycle in central New York State and other parts of the northeastern United States. The seasonal abundance of adults in Tompkins County, New York, shows a bimodal pattern in some years, and a skewed unimodal pattern in others. We studied the incidence of diapause, the potential for successful development of two generations in the field, and the dates of adult emergence from overwintering pupae to determine whether these seasonal patterns are the result of bivoltinism.
2. Insects from Tompkins County, reared as larvae under 16L:8D photoperiod, uniformly enter pupal diapause.
3. Comparison of the heat units required for successful development of two generations with the heat units available in the field during 11 years shows that emergence of non-diapausing individuals would occur too late in the summer to contribute to the second peak of butterfly abundance. Offspring of non-diapausing individuals could only rarely complete development before the end of the growth season.
4. Diapausing offspring of butterflies collected in early June and late July differed sufficiently in dates of emergence to account for the field pattern of seasonal abundance.
5. Electrophoretic studies revealed no evidence of genetic isolation between early and late emerging butterflies.
6. These results suggest that polymodal emergence of diapausing insects can masquerade as a bivoltine life cycle.     

Recruitment and distribution of Dreissena polymorpha (Bivalvia) on substrates of different shape and orientation

Dreissena polymorpha recruitment on artificial substrates was studied in the Włocławek Dam Reservoir (the Vistula River, Poland). Densities on downstream and upstream vertical surfaces of plastic plates differed significantly from each other, with the former settled by more individuals. Vertical and horizontal plates, as well as upper and lower horizontal surfaces were settled similarly. In another experiment mussels settled on flat, convex and concave glass surfaces, directed upstream or downstream. Among the upstream surfaces, the concave ones were the most densely settled. No significant differences in mussel recruitment on various downstream surfaces were found. Thus, substrate shape influenced mussels only when they were exposed to water flow. Mussels were aggregated (Lloyd index > 1) along all the edges of the horizontal plates and along the upper edge of the vertical ones. Such distribution was probably caused by the post‐settlement movement of metamorphosed individuals. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Multi‐generational long‐distance migration of insects: studying the painted lady butterfly in the Western Palaearctic

Long‐range, seasonal migration is a widespread phenomenon among insects, allowing them to track and exploit abundant but ephemeral resources over vast geographical areas. However, the basic patterns of how species shift across multiple locations and seasons are unknown in most cases, even though migrant species comprise an important component of the temperate‐zone biota. The painted lady butterfly Vanessa cardui is such an example; a cosmopolitan continuously‐brooded species which migrates each year between Africa and Europe, sometimes in enormous numbers. The migration of 2009 was one of the most impressive recorded, and thousands of observations were collected through citizen science programmes and systematic entomological surveys, such as high altitude insect‐monitoring radar and ground‐based butterfly monitoring schemes. Here we use V. cardui as a model species to better understand insect migration in the Western Palaearctic, and we capitalise on the complementary data sources available for this iconic butterfly. The migratory cycle in this species involves six generations, encompassing a latitudinal shift of thousands of kilometres (up to 60 degrees of latitude). The cycle comprises an annual poleward advance of the populations in spring followed by an equatorward return movement in autumn, with returning individuals potentially flying thousands of kilometres. We show that many long‐distance migrants take advantage of favourable winds, moving downwind at high elevation (from some tens of metres from the ground to altitudes over 1000 m), pointing at strong similarities in the flight strategies used by V. cardui and other migrant Lepidoptera. Our results reveal the highly successful strategy that has evolved in these insects, and provide a useful framework for a better understanding of long‐distance seasonal migration in the temperate regions worldwide.     

Scleractinian coral recruitment patterns at Salt River submarine canyon,St. Croix,U.S. Virgin Islands

Scleractinian coral recruitment patterns were studied at depths of 9, 18, 27 and 37 m on the east and west walls of Salt River submarine canyon, St. Croix, U.S. Virgin Islands, by censusing coral juveniles which settled on experimental settling plates placed on the reef for 3–26 months as well as coral juveniles within quadrats on the reef. The most common species in the juvenile population within quadrats were Agaricia agaricites, Porites astreoides, Madracis decactis, Stephanocoenia michelinii, and A. lamarcki. The only species settling on settling plates were Agaricia spp., Madracis decactis, Porites spp., Stephanocoenia michelinii and Favia fragum. A total of 271 corals settled on 342 plates, with 51% of the juveniles on the east wall and 49% on the west wall. Of these 34% settled on horizontal surfaces and 66% on vertical surfaces. Based on results from quadrats, Agaricia agaricites and Porites astreoides had high recruitment rates relative to their abundance on the reef. In contrast, Agaricia lamarcki, Montastraea annularis, M. cavernosa and Siderastrea siderea had high amounts of cover compared to their abundance as juveniles within quadrats. The mean number of juveniles per m² within quadrats ranged from 3 to 42. In general, there was a decrease in the mean number of juveniles and the number of species with depth. Total number of juveniles on settling plates was highest at 18 m on both walls. The largest number within quadrats was at 18 m on the east wall, followed by 9 m and 18 m on the west wall. High rates of coral recruitment tended to be associated with low algal biomass and relatively high grazing pressure by urchins and fishes.     

八大公山国家级自然保护区不同生境蝶类群落特征与月动态

为了解八大公山国家级自然保护区内的蝴蝶群落组成及海拔分布, 作者于2016-2018年间对该区域不同生境的蝴蝶群落进行了系统调查和多样性分析, 并持续观测其群落的月动态变化。本研究共记录蝴蝶6,164只, 隶属于5科107属191种。低海拔(250-450 m)生境记录到的蝴蝶以凤蝶亚科为主, 高海拔(1,200-1,400 m)生境以粉蝶亚科为主, 而中海拔(700-900 m)生境无明显的蝴蝶优势类群。相似性分析结果表明, 各生境存在很高比例的共有种(59%以上), 这些共有种在不同生境的个体数分布存在很大的差异。季节动态分析结果表明, 八大公山蝴蝶群落的物种数、个体数及多样性指数在4-6月逐渐上升, 7月达到峰值, 8-9月逐渐下降。总体来说, 八大公山的蝴蝶群落组成沿海拔梯度呈现垂直分布差异, 高海拔与低海拔存在明显的异质性, 中海拔则呈现出一种过渡状态; 且八大公山不同海拔的蝴蝶群落表现出较为一致的季节动态, 都具有很高比例的物种更替; 相对于低海拔, 高海拔生境蝴蝶群落的活跃期更短, 物种的时间周转率更高。     

Effects of plant structure on butterfly diversity in Mt. Marsabit Forest – northern Kenya

Butterflies, like most forest dependent animals are good ecological indicators of the health of the forests they dwell. For example, butterfly species richness decreases after a forest disturbance and fragmentation but a few species may subsequently invade the forest fragment and boost the species richness. Studies were conducted to determine the effects of human activity and seasonal changes on butterfly species in the affected new habitats. Results showed that both seasonal and habitat changes significantly affect the butterfly abundance (P = 0.0001). Similarly, there was significant correlation between plant diversity and butterfly diversity in wet season (r = 0.854) and dry season (r = 0.855). The significance of these studies as a useful tool for sustainable forest use and conservation is discussed.     

Substrate selection and larval settlement by Cupelopagis vorax

Cupelopagis vorax was sampled for one year with a glass slide sampler. Slides were collected every two weeks and the numbers and locations of settled individuals noted. Reproductive condition of the collected rotifers was recorded. The population appeared suddenly and rapidly attained peak numbers. C. vorax shows a distinct preference for the underside of horizontally-oriented surfaces. Sexual reproduction occurred when the number of settling individuals was maximum.     

宁夏贺兰山自然保护区蝴蝶群落多样性及其环境影响因子

宁夏贺兰山自然保护区蝴蝶群落多样性及其与环境因素的关系,2017年5-9月采用样线法对贺兰山东麓6类生境和不同干扰类型10条样线的蝴蝶群落结构及其多样性季节动态进行调查。共记录蝴蝶5科36属45种,蛱蝶科Nymphalidae的属和物种数最多,为17属19种;凤蝶科Papilionidae最少,仅1属1种。菜粉蝶Pieris rapae、云粉蝶Pontia daplidice、斑缘豆粉蝶Colias erate和小檗绢粉蝶Aporia hippia是该地区的优势种,个体数量分别占总个体数的11.76%、11.63%、11.21%和10.17%。不同生境样线优势类群和常见类群不同。蝴蝶的栖息地偏好与寄主植物有关,蝴蝶的生境分布类型可分为生境广布型、湿润平原型、荒漠半荒漠草原型和山地森林型。蝴蝶群落Shannon-Wiener多样性和丰富度指数以灰榆疏林草地生境最高,优势度最低。各物种在生境内的季节变化趋势与不同生境植被生长季节相关,高峰期为7-8月。不同调查时间蝴蝶的优势种和常见种不同。物种数以7月份调查最多,有33种,占全年调查总物种数的73.33%;5月份调查最少,有20种。蝴蝶群落Shannon-Wiener多样性和丰富度指数以8月份最大,5月份最小。蝴蝶成虫发生类型分为全年发生型、春季型、夏季型和夏秋季型。不同生境和季节发生的优势种可以作为对生境状况进行评估的指示类群。采用CCA分析物种分布与微环境因子的关系,海拔对蝴蝶物种多样性分布格局有显著影响。蝴蝶丰富度与海拔、温度、风速显著正相关。适度干扰有利于蝶类多样性增加,较强的人为干扰会影响蝶类栖息环境,降低蝶类多样性。因此,生境差异性和干扰与蝴蝶群落的物种多样性密切相关,维持贺兰山垂直植被带的生境异质性和保持适度干扰是保护蝴蝶多样性的关键。     

Sources of intraspecific variation in the hostplant seeking behavior of Colias butterflies

Summary Egg-laying females of the legume-feeding butterfly Colias philodice eriphyle were observed within a high-altitude study site during 1977 and 1978. Average oviposition selectivity showed two patterns of seasonal variation. First, second-brood females laid eggs more frequently after alighting upon hostplants than did first-brood females in both years. Second, a consistent decline in post-alighting oviposition probability near the end of the second brood corresponded with a dramatic decrease in the water content of hostplant foliage near the end of the dry summer season. In addition to seasonal variation in oviposition behavior, individual females landed and oviposited upon widely varying sets of legume hostplant species. By sampling hostplant abundances along the flightpaths of observed females, we show that individuals varied in their tendency to land upon different hostplants. Females tended to specialize upon one or two species, at least in the short term, and the pattern of oligophagy for the population as a whole is partly generated by variation in the host-seeking behavior of individual females.     

Seasonal Dynamics of Pelagic Larvae and Settling of the Fouling Organisms in Conditions of Thermal Pollution

Year-round comprehensive study of fouling of the cooling system of the Vladivostok Heat Power Plant (VTETs-2) was carried out. The seasonal dynamics of pelagic larvae, their settling, and succession of fouling communities on test plates were analyzed in the intake scoop (Ussuriiskii Bay) and in Zolotoi Rog Bay (Amurskii Bay), which are subjected to thermal pollution by dump waters of VTETs-2. It was shown that the barnacles Balanus crenatus, B. improvisus, and B. amphitrite; bivalves Mytilus trossulus and Crassostrea gigas; polychaetes Polydora limicola and Hydroides ezoensis; and ascidians Molgula manhattensis and Diplosoma mitsukurii were background species in the plate fouling. A high correlation between the seasonal dynamics of larval plankton and the settling of spat was recorded only in some species. The total larval density in Zolotoi Rog Bay, despite the critical level of its pollution, more than 4 times exceeded that of the relatively clean Ussuriiskii Bay. The number of recorded species on the test plates was 2 times higher in Ussuriiskii Bay than in Zolotoi Rog Bay; however, the biomass and population density of settled spat of the dominant forms was several times lower in Ussuriiskii Bay. Thanks to thermal pollution, Zolotoi Rog Bay is an intermediate step for the introduction and acclimation of tropical species, such as B. amphitrite and M. manhattensis, brought by long-distance vessels. Measures aimed at the prevention of intensive settling of mytilids in the cooling system of VTETs-2 are suggested.     

Substrate Marking by an Invasive Ladybeetle: Seasonal Changes in Hydrocarbon Composition and Behavioral Responses

The multicolored Asian ladybeetle, Harmonia axyridis (Pallas), aggregates inside dwellings during the winter to survive the cold. Recent published reports have highlighted that overwintering individuals use hydrocarbon markings deposited on surfaces by conspecifics to orient toward aggregation sites. In the current study, monthly GC-MS analyses revealed seasonal modifications in the chemical profile of substrate markings deposited by moving individuals. The markings of overwintering ladybeetles contained larger proportions of heptacosadiene, nonacosadiene, hentriacontadienes, and methyl-nonacosanes, along with a lower proportion of heptacosene and nonacosene. This finding suggests the importance of the unsaturated and/or branched hydrocarbons in the H. axyridis aggregation process. Subsequently, we conducted behavioral assays to test whether (1) there is seasonal variation in the behavioral response of H. axyridis individuals toward substrate markings deposited by conspecifics in the same physiological state and (2) the observed behavioral modification is due to a change in ladybeetle sensitivity and/or a change in the chemical composition of the substrate marking. The results indicate that overwintering individuals exhibit a stronger “following” response toward conspecific substrate markings. This behavior is linked to both the physiological state of ladybeetles and the specific chemical profile of the marking biomolecules deposited under overwintering conditions.     

Phenotypic plasticity in field populations of the tropical butterfly Hypolimnas bolina (L.) (Nymphalidae)

Phenotypic plasticity may enable organisms to maximize their fitness in seasonally variable environments. However, in butterflies, seasonal polyphenism is often striking but functionally obscure. This paper addresses the possible adaptive significance of phenotypic variation in the tropical butterfly Hypolimnas bolina (L.) (Nymphalidae). Plasticity in body size and wing coloration can be elicited in this species under laboratory conditions, however it is not known how this plasticity is expressed in the wild. Moreover, adult H. bolina spend the winter dry season in a reproductive diapause, which allows certain predictions regarding the occurrence of seasonal plasticity. Based on consideration of the requirements of diapausing and directly developing individuals, we predicted that if seasonal plasticity in phenotype were adaptive, then overwintering individuals should be larger and darker than their directly developing counterparts. This prediction was largely - although not entirely - fulfilled. Dry season butterflies were duller and darker than their wet season counterparts (this plasticity was superimposed on a genetic colour polymorphism), however size plasticity varied geographically. Dry season adults were consistently larger than wet season adults in the tropical north, but not in the south. We use these findings to discuss the possible adaptive significance of seasonal variation in the colour and size of this tropical butterfly.     

Size matters for violent discharge height and settling speed of Sphagnum spores: important attributes for dispersal potential

Background and Aims

Initial release height and settling speed of diaspores are biologically controlled components which are key to modelling wind dispersal. Most Sphagnum (peat moss) species have explosive spore liberation. In this study, how capsule and spore sizes affect the height to which spores are propelled were measured, and how spore size and spore number of discharged particles relate to settling speed in the aspherical Sphagnum spores.

Methods

Spore discharge and spore cloud development were filmed in a closed chamber (nine species). Measurements were taken from snapshots at three stages of cloud development. Settling speed of spores (14 species) and clusters were timed in a glass tube.

Key Results

The maximum discharge speed measured was 3·6 m s⁻¹. Spores reached a maximum height of 20 cm (average: 15 cm) above the capsule. The cloud dimensions at all stages were related positively to capsule size (R² = 0·58–0·65). Thus species with large shoots (because they have large capsules) have a dispersal advantage. Half of the spores were released as singles and the rest as clusters (usually two to four spores). Single spores settled at 0·84–1·86 cm s⁻¹, about 52 % slower than expected for spherical spores with the same diameters. Settling speed displayed a positive curvilinear relationship with spore size, close to predictions by Stokes'' law for spherical spores with 68 % of the actual diameters. Light-coloured spores settled slower than dark spores. Settling speed of spore clusters agrees with earlier studies. Effective spore discharge and small, slowly settling spores appear particularly important for species in forested habitats.

Conclusions

The spore discharge heights in Sphagnum are among the greatest for small, wind-dispersed propagules. The discharge heights and the slow settling of spores affect dispersal distances positively and may help to explain the wide distribution of most boreal Sphagnum species.     

From savannah to farmland: effects of land‐use on mammal communities in the Tarangire–Manyara ecosystem,Tanzania

Land‐use change is considered a major driver of biodiversity loss. In the western part of the Tarangire–Manyara ecosystem, we assessed large mammal species richness along a land‐use gradient (national park, uninhabited pastoral area and settled pastoral‐ and farmland). We found the highest species richness in the national park and in the pastoral area and lowest species richness in the settled and farmed area. There was little evidence of seasonal changes in species diversity. Except for top‐order carnivores, all functional feeding guilds were still represented in pastoral and settled areas. Although we did not find significant differences in body mass distributions and species’ representation of feeding guilds between the study sites, there was a trend that omnivores, mesopredators and top‐order carnivores tended to occur at lower species richness in agricultural areas than in the pastoral and fully protected areas. These results indicate that areas used for livestock keeping can maintain high wildlife species richness and that direct and indirect effects of agricultural and settlement expansions are the main drivers of species richness loss in the Tarangire–Manyara ecosystem and possibly other African savannah ecosystems. These results are useful for informed land‐use planning that aims to maintain species diversity and ecological connectivity between protected areas.