Conversion of sagebrush shrublands to exotic annual grasslands negatively impacts small mammal communities

Aim The exotic annual cheatgrass (Bromus tectorum) is fast replacing sagebrush (Artemisia tridentata) communities throughout the Great Basin Desert and nearby regions in the Western United States, impacting native plant communities and altering fire regimes, which contributes to the long‐term persistence of this weedy species. The effect of this conversion on native faunal communities remains largely unexamined. We assess the impact of conversion from native perennial to exotic annual plant communities on desert rodent communities. Location Wyoming big sagebrush shrublands and nearby sites previously converted to cheatgrass‐dominated annual grasslands in the Great Basin Desert, Utah, USA. Methods At two sites in Tooele County, Utah, USA, we investigated with Sherman live trapping whether intact sagebrush vegetation and nearby converted Bromus tectorum‐dominated vegetation differed in rodent abundance, diversity and community composition. Results Rodent abundance and species richness were considerably greater in sagebrush plots than in cheatgrass‐dominated plots. Nine species were captured in sagebrush plots; five of these were also trapped in cheatgrass plots, all at lower abundances than in the sagebrush. In contrast, cheatgrass‐dominated plots had no species that were not found in sagebrush. In addition, the site that had been converted to cheatgrass longer had lower abundances of rodents than the site more recently converted to cheatgrass‐dominated plots. Despite large differences in abundances and species richness, Simpson’s D diversity and Shannon‐Wiener diversity and Brillouin evenness indices did not differ between sagebrush and cheatgrass‐dominated plots. Main conclusions This survey of rodent communities in native sagebrush and in converted cheatgrass‐dominated vegetation suggests that the abundances and community composition of rodents may be shifting, potentially at the larger spatial scale of the entire Great Basin, where cheatgrass continues to invade and dominate more landscape at a rapid rate.     

Landscape mosaic of Araucaria forest and forest monocultures influencing understorey spider assemblages in southern Brazil

Abstract This study investigates how abundance, diversity and composition of understorey spiders were influenced by four different forest habitats in a southern Brazilian Araucaria forest. The study area encompasses a landscape mosaic comprised of Araucaria forest, Araucaria plantation, Pinus plantation, and Eucalyptus plantation. Understorey spiders were collected by beating the vegetation inside three patches of each forest habitat. To assess possible predictors of spider assemblage structure, several patch features were analysed: potential prey abundances, estimation of vegetation cover, diversity index of vegetation types, patch ages, patch areas, and geographical distance between patches. To assess the influence of high‐level taxa approaches on spider assemblage patterns, analyses were carried out individually for family, genera and species levels. Additionally, Mantel tests were carried out in underlying similarity matrices between each taxon. Significant differences in spider abundances among forest habitats were found. Pinus plantations showed the highest abundance of spiders and Eucalyptus plantations showed the lowest abundance. Spider abundance was significantly influenced by patch ages, geographical distance and vegetation cover. Expected numbers of families, genera and species did not vary among forest habitats. Spider composition of two Eucalyptus patches differed from the other forest patches, probably due to their low vegetation cover and isolation. Genera composition was the best correlate of species composition, showing that a higher‐level surrogate can be an alternative to the species approach. The understorey spider diversity in this managed area could be maintained when suitable habitat structures are provided, thus ensuring the connectivity between different habitat types. Further studies should focus on individual species responses to the conversion of native forest to monocultures.     

Effects of landscape cover and local habitat characteristics on visiting bees in tropical orchards

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Invertebrate community response to fire and rodent activity in the Mojave and Great Basin Deserts

Recent increases in the frequency and size of desert wildfires bring into question the impacts of fire on desert invertebrate communities. Furthermore, consumer communities can strongly impact invertebrates through predation and top‐down effects on plant community assembly. We experimentally applied burn and rodent exclusion treatments in a full factorial design at sites in both the Mojave and Great Basin deserts to examine the impact that fire and rodent consumers have on invertebrate communities. Pitfall traps were used to survey invertebrates from April through September 2016 to determine changes in abundance, richness, and diversity of invertebrate communities in response to fire and rodent treatments. Generally speaking, rodent exclusion had very little effect on invertebrate abundance or ant abundance, richness or diversity. The one exception was ant abundance, which was higher in rodent access plots than in rodent exclusion plots in June 2016, but only at the Great Basin site. Fire had little effect on the abundances of invertebrate groups at either desert site, with the exception of a negative effect on flying‐forager abundance at our Great Basin site. However, fire reduced ant species richness and Shannon's diversity at both desert sites. Fire did appear to indirectly affect ant community composition by altering plant community composition. Structural equation models suggest that fire increased invasive plant cover, which negatively impacted ant species richness and Shannon's diversity, a pattern that was consistent at both desert sites. These results suggest that invertebrate communities demonstrate some resilience to fire and invasions but increasing fire and spread of invasive due to invasive grass fire cycles may put increasing pressure on the stability of invertebrate communities.     

“No signs of saturation”: long-term dynamics of vascular epiphyte communities in a human-modified landscape

It is debated whether slowing human population growth and intense urbanization may result in a slowdown of deforestation and an acceleration of natural forest regeneration. In a fragmented landscape the structure and composition of developing secondary forests will strongly depend on the local species pool. Thus, the understanding how organisms cope with biotic and abiotic challenges outside pristine habitats is pivotal. Structurally dependent, vascular epiphytes are an important biotic component of tropical forests. In human-modified tropical landscapes potential hosts are often still present. We aimed to assess if human-modified landscapes offer a refuge habitat in which epiphytes can form metacommunities that are ultimately viable. Eight years after an initial assessment we recensused the epiphytes in pasture trees in western Panama along a strong rainfall gradient. We document a threefold abundance increase (ca. 20,000 vs. >60,000 individuals) and an increase in species-richness (66 vs. 86 mostly drought-tolerant species). This large net increase suggests a highly dynamic system. Although absolute abundances changed dramatically, the relative contribution of major taxonomic groups to overall diversity and abundance changed little. Neither rainfall nor tree growth had a significant effect on relative annual community growth rates. At the plot level (=metacommunities), abundance increase was mostly due to the species already present in the first census, at the tree level (=communities) the contribution of new and old species was comparable. The documented long-term trend in epiphyte metacommunities in a human-modified landscape suggests that a diverse set of species sustains viable metacommunities and is likely to provide structural diversity to developing secondary forest.     

Diversity and similarity of butterfly communities in five different habitat types at Tam Dao National Park, Vietnam

Diversity and similarity of butterfly communities were assessed in five different habitat types (from natural closed forest to agricultural lands) in the mountains of Tam Dao National Park, Vietnam for 3 years from 2002 to 2004. The line transect count was used to record species richness and abundance of butterfly communities in the different habitat types. For each habitat, the number of species and individuals, and indices of species richness, evenness and diversity of butterfly communities were calculated. The results indicated that species richness and abundance of butterfly communities were low in the natural closed forest, higher in the disturbed forest, highest in the forest edge, lower in the shrub habitat and lowest in the agricultural lands. The indices of species richness, evenness and diversity of butterfly communities were low in agricultural lands and natural closed forest but highest in the forest edge and shrub habitats. The families Satyridae and Amathusiidae have the greatest species richness and abundance in the natural closed forest, with a reduction in their species richness and abundance from the natural closed forest to the agricultural lands. Species composition of butterfly communities was different among five different habitat types (40%), was similar in habitats outside the forest (68%) and was similar in habitats inside the forest (63%). Diversity and abundance of butterfly communities are not different between the natural closed forest and the agriculture lands, but species composition changed greatly between these habitat types. A positive correlation between the size of species geographical distribution range and increasing habitat disturbance was found. The most characteristic natural closed forest species have the smallest geographical distribution range.     

Changes in woody vegetation abundance and diversity after natural disturbances causing different levels of mortality

Questions: How does woody vegetation abundance and diversity differ after natural disturbances causing different levels of mortality? Location: Abies balsamea–Betula papyrifera boreal mixed‐wood stands of southeast Quebec, Canada. Methods: Woody vegetation abundance and diversity were quantified and compared among three disturbance‐caused mortality classes, canopy gap, moderate‐severity disturbances, and catastrophic fire, using redundancy analysis, a constrained linear ordination technique, and diversity indices. Results: Substantial changes in canopy tree species abundance and diversity only occurred after catastrophic fire. Shade‐tolerant, late‐successional conifer species remained dominant after canopy gap and moderate‐severity disturbances, whereas shade‐intolerant, early‐successional colonizers dominated canopy tree regeneration after catastrophic fire. Density and diversity of mid‐tolerant and shade‐intolerant understory tree and shrub species increased as the impact of disturbance increased. Highest species richness estimates were observed after catastrophic fire, with several species establishing exclusively under these conditions. Relative abundance of canopy tree regeneration was most similar after canopy gap and moderate‐severity disturbances. For the sub‐canopy tree and shrub community, relative species abundances were most similar after moderate‐severity disturbances and catastrophic fire. Vegetation responses to moderate‐severity disturbances thus had commonalities with both extremes of the disturbance‐caused mortality gradient, but for different regeneration layers. Conclusions: Current spatio‐temporal parameters of natural disturbances causing varying degrees of mortality promote the development of a complex, multi‐cohort forest condition throughout the landscape. The projected increase in time intervals between catastrophic fires may lead to reduced diversity within the system.     

Effects of landscape complexity and stand factors on arthropod communities in poplar forests

The arthropod communities are influenced by both local conditions and features of the surrounding landscape. Landscape complexity and stand factors may both influence arthropod communities in poplar forests, but the multiscale effects of these factors on poplar defoliators and natural enemies are still poorly understood. We collected poplar arthropods at 30 sampling sites within five forest landscapes in Xinjiang, China, and assessed whether landscape complexity and stand factors influence species abundance and diversity of poplar arthropods. Landscape complexity was quantified by several independent metrics of landscape composition, configuration, and connectivity at three spatial scales. We also determined the most powerful explanatory variables and the scale effect of each arthropod. Results found that landscape complexity and stand factors had different effects on different poplar arthropod communities. Landscape complexity promoted natural enemies at different spatial scales, but it inhibited the population of poplar defoliators at the scale of 200 m. Specifically, the abundance and diversity of all defoliators decreased with increasing proportion of nonhost plants. Landscape diversity only had a negative effect on defoliator abundance. The shape complexity of habitat patches increased the abundance of carabid beetles but reduced the abundance of green leafhoppers and migratory locusts. The abundance and diversity of predators increased with increasing structural connectivity of forest landscape. Additionally, both the abundance and diversity of all defoliators were positively correlated with the average height of herbaceous plants. Diversity of all defoliators increased with increasing size of host trees. The distance from sampling site to the nearest village positively influenced the abundance and diversity of all predators. Arthropod abundance and diversity in poplar forests were driven by stand factors and landscape complexity. Therefore, maintaining complex shape and structural connectivity of habitat patches and keeping poplar stands away from the village are crucial for management of forest landscape to enhance natural enemies. And in order to reduce the abundance of defoliators in poplar forest, the diversity of surrounding habitat types should be promoted within 200 m radii.     

Abundance and diversity of rodents at the human–wildlife interface in Western Serengeti, Tanzania

Rodent species abundance and diversity in Western Serengeti are evaluated and discussed in relation to different levels of conservation status [Unprotected Area (UA), Game Reserve (GR) and National Park (NP)] and broad site differences in human livelihood activities. A total of 2170 individuals, spread over 16 rodent species, were caught in a capture‐mark‐recapture study which covered both the dry and wet seasons. The more humid site (Tabora B) in the northern part of Serengeti had the highest diversity of rodents followed by the Mihale site at the western extension. The driest site at Robanda had the lowest overall species diversity. Diversity also varied between the three levels of conservation status whereby the UA had the least diversity while the NP, which enjoyed the highest level of conservation status, had the highest diversity of rodents. Unprotected Area and NP plots at Tabora B showed a rodent species similarity index of 40%; all the other paired plots scored over 50% similarity indices, suggesting that, within a site, species composition did not vary significantly between the three levels of conservation status. The Robanda site had the highest (56%) overall abundance of rodents; Mihale and Tabora B sites had about the same level of rodent abundance (20 and 24% respectively). For the Mihale site, Mastomys natalensis ranked first followed by Arvicanthis niloticus and Tatera robusta, each of which contained 40, 38 and 16%, respectively, of all individuals caught at the site. For the Robanda site, the figures were 66%A. niloticus, 22%M. natalensis and 9%T. robusta; while for the Tabora B site the scores were 37%M. natalensis, 18%T. robusta and 11%Lemniscomys barbarus. The differences in diversity, species composition and population abundance appear to result largely from physiognomic vegetation types, and habitat perturbations caused by livelihood activities in Western Serengeti.     

黄河中下游农业景观中景观简化对传粉昆虫多样性的影响——以巩义市为例

在农业景观中,传粉昆虫的生存繁衍与半自然生境的面积大小有关。集约化生产方式使半自然生境比例逐渐减少,农田比例不断增加,随着景观简化梯度的变化(农田比例逐渐增大),传粉昆虫群落多样性将会发生怎样的变化?选择黄河中下游典型农区巩义市为研究区域,采用诱捕盘法(Pan traps)进行农田、林地的传粉昆虫取样,以21个样点作为景观简化梯度(农田比例范围5%—86%)的呈现,基于每个样点的传粉昆虫多度和丰富度变化来探究景观简化对传粉昆虫多样性的影响。结果显示:区内累计捕获传粉昆虫39660头,优势类群包括双翅目(Diptera)、膜翅目(Hymenoptera)、鞘翅目(Coleoptera)等。采用逐步回归分析及线性拟合后发现景观简化程度与传粉昆虫多度和丰富度呈显著负相关(P0.05);景观简化对传粉昆虫类群间的影响也是有差异的,其中对鞘翅目多度的影响最为密切(R~2=0.27),同时对膜翅目和双翅目也有较大影响(R~2=0.14、R~2=0.11),景观简化与鳞翅目多度呈正相关;随景观简化的程度加深,农田生境中膜翅目多度呈显著下降趋势(P0.05),而林地中膜翅目多度变化不明显。在未来的景观规划中,应着重考虑传粉昆虫中鞘翅目类群的栖息地变化及食物资源状况。依据研究结果建议林地生境中应注重保护现有的自然植被群落,在人工林中可以种植一定面积的蜜粉源植物;农田生境内对杂草群落、半自然生境斑块进行合理规划的基础上,还可以种植线性景观植物作为传粉昆虫的食物源。     

Diversity and Coexistence of Ectoparasites in Small Rodents in a Tropical Dry Forest

To understand the mechanisms driving species diversity is central to community ecology. Here, we explored if habitat partitioning is associated with a species‐rich ectoparasite community in small rodents from a tropical dry forest in western Mexico. We trapped 199 mice in three 0.5 ha‐plots from eight small rodent species for every two months, from July 2011 to April 2012, and collected their ectoparasites. We identified 17 species of mites, two sucking lice species, two phoretic species, and one commensal species. The most abundant ectoparasite species was Steptolaelaps liomydis, representing 42 percent of all ectoparasites collected; seven ectoparasite species had < 10 individuals. Eighteen ectoparasite species (of 22 species) were collected from the most abundant rodent Liomys pictus. C‐score and the number of checkerboard species pairs were significantly higher against a random expectation. Ectoparasite species in L. pictus mice showed host microhabitat partitioning; Fahrenholzia ehrlichi and Fahrenholzia texana were found only in the anterior dorsal area, Ornithonysus sp. occurred along the dorsal part, Ixodes species were restricted to the ears, and Steptolaelaps liomydis was found throughout the body. We also identified ectoparasite communities with distinct species composition in two rodent species that use contrasting macrohabitats (L. pictus, strictly terrestrial; Peromyscus perfulvus, mostly arboreal). The remaining and low abundant rodent species showed a species‐poor ectoparasite community composition. We conclude that habitat partitioning at both macro and microhabitat scales appeared to characterize the species‐rich ectoparasite community. Conversely, most rodent host species with low abundances showed a species‐poor ectoparasite community.     

Variation in composition of two bumble bee species across communities affects nectar robbing but maintains pollinator visitation rate to an alpine plant,Salvia przewalskii

1. In many flowering plants, bumble bees may forage as both pollinators and nectar robbers. This mixed foraging behaviour may be influenced by community context and consequently, potentially affect pollination of the focal plant. 2. Salvia przewalskii is both pollinated and robbed exclusively by bumble bees. In the present study area, it was legitimately visited by two species of bumble bees with different tongue length, Bombus friseanus and Bombus religiosus, but it was only robbed by Bombus friseanus, the shorter‐tongued bumble bee. The intensity of nectar robbing and pollinator visitation rate to the plant were investigated across 26 communities in the Hengduan Mountains in East Himalaya during a 2‐year project. For each of these communities, the floral diversity, and the population size and floral resource of S. przewalskii were quantified. The abundances of the two bumble bee species were also recorded. 3. Both nectar robbing and pollinator visitation rate were influenced by floral diversity. However, pollinator visitation rate was not affected by nectar robbing. The results revealed that relative abundance of the two bumble bee species significantly influenced the incidence of nectar robbing but not the pollinator visitation rate. Increased abundance of B. religiosus, the legitimate visitors, exacerbated nectar robbing, possibly by causing B. friseanus to shift to robbing; however, pollinator visitation remained at a relatively high level. 4. The results may help to explain the persistence of both nectar robbing and pollination, and suggest that, in comparison to pollination, nectar robbing is a more unstable event in a community.     

围垦对南汇东滩湿地大型底栖动物的影响

为评价围垦促淤工程对南汇东滩湿地大型底栖动物生态学的影响,根据2004年10月和2009年10月对南汇东滩湿地底栖动物的定量定性调查数据,进行对比分析。结果表明:2004年共采集到大型底栖动物32种,其中在经围垦促淤后形成的堤内、堤外两个区域分别采集到底栖动物20种和21种,2009年堤内外分别为9种和19种,共26种;2004年堤内和堤外优势种分别为8种和4种,共有优势种为中华蜾蠃蜚和谭氏泥蟹,2009年堤内优势种仅有摇蚊幼虫1种,堤外有4种,优势种种类组成也发生了很大变化;2004年大型底栖动物的平均丰度和生物量分别为44.15个/m2和38.80 g/m2,2009年为86.76个/m2和1.97g/m2,2009年堤内、堤外的生物量与2004年相比明显降低,丰度变化则相对较小;运用SPSS软件的单因素方差分析、群落聚类和MDS排序对南汇东滩湿地各断面进行群落结构分析,结果表明围垦是大型底栖动物群落结构改变的一个重要因素,围垦造成堤内底栖动物群落结构发生了明显差异,堤外群落结构变化相对较小。大型底栖动物的生物多样性指数(Shannon-Weiner指数H'、Pielou均匀度指数J'、Margalef物种丰富度指数d和Simpson指数D)受到围垦促淤工程的影响均降低,尤其以围垦圈淤的堤内湿地生物多样性指数最低。围垦促淤工程对盐度、潮汐动力、底质特征的改变以及人类活动等因素是影响大型底栖动物群落结构的主要原因,工程结束后的湿地生态修复十分必要。     

The cascading effects of elephant presence/absence on arthropods and an Afrotropical thrush in Arabuko‐Sokoke Forest,Kenya

Although studies have explored how habitat structure and disturbance affect arthropod communities, few have explicitly tested the effects of both structure and disturbance level across trophic levels and phyla. We present here the results of a study conducted in the Arabuko‐Sokoke Forest (ASF) of coastal Kenya, in which abundance of arthropods and one of their avian predators, the East Coast Akalat Sheppardia gunning sokokensis was compared in relatively undisturbed habitat (outside elephant roaming areas) and in disturbed habitat (inside elephant roaming areas). Vegetation structure in both areas was measured using several metrics, including leaf litter depth, understory vegetation density, animal disturbance and fallen log counts. Leaf litter and coleopteran abundance were higher outside the elephant roaming areas, whereas understory visibility, animal disturbance and dipteran diversity were much higher inside the elephant areas. Species composition of several arthropod taxa (e.g. Hymenoptera, Coleoptera, Diptera, Hemiptera and Araneae) was also influenced by degree of disturbance, whereas akalat abundance was inversely related to understory visibility. Our results suggest that differences in species sensitivity to habitat disturbance and vegetation structure across trophic levels should be incorporated into the management and conservation of rare and endangered species.     

How Does Landscape Modification Induce Biological Homogenization in Tropical Stream Metacommunities?

Habitat modification can homogenize biological communities. Beta diversity analyses provide key information for understanding biotic homogenization, especially given recent conceptual and methodological advances. Here, we investigated if landscape modification was associated with taxonomic homogenization in 32 stream insect communities from the Brazilian Atlantic Forest. We investigated: (1) if the way we defined landscape affected our estimates of beta diversity; (2) to what extent changes in species composition versus relative abundance caused the observed homogenization; and (3) if environmental heterogeneity among modified habitats influenced homogenization. We detected taxonomic homogenization caused by landscape modification only when we used refined landscape categorizations and abundance‐based diversity measures. For forested streams, changes in relative abundance rather than absolute taxonomic composition increased the biological variation. Forested streams were generally more heterogeneous, with a variable set of abundant genera; by contrast, non‐forested streams were more homogeneous, with the same set of genera being more or less abundant. We suggest that landscape modification by agriculture, pasture, and silviculture reduces beta diversity by limiting the colonization of potential species, and, ultimately, causing taxonomic homogenization. Studies investigating biotic homogenization should include multiple dissimilarity measures representing changes in relative species abundance and community composition.     

Edge effects across boundaries between natural and restored jarrah (Eucalyptus marginata) forests in south‐western Australia

Edge effects are a widespread and ubiquitous ecological phenomenon, yet they remain poorly studied across edges between restored and natural forests. To address this lack of knowledge, we studied vertebrate communities across edges between 3‐year old restored mine‐pits and adjacent unmined forest in the jarrah (Eucalyptus marginata) forest of south‐western Australia. We found that mammal communities showed no edge response but reptile communities did. Overall reptile abundance and Morethia obscura abundance were higher in unmined forest along edges, Egernia napoleonis abundance was lower in unmined forest along edges, while Pogona minor abundance was lower in restored mine‐pits along edges. Predictive models were unable to predict species edge responses, due to the lack of knowledge of the ecology of jarrah forest reptiles, but proved useful in identifying potential ecological mechanisms behind observed edge responses and suggested that potential mechanisms were likely different for each species. Our study is the first to show edge responses in both habitats forming the edge between restored and natural forests, emphasizing the importance of studying both habitats forming the edge. Our results also suggest that, despite being poorly studied, edge responses are common across edges between restored and natural forest and result from a variety of ecological mechanisms. An increased understanding of the ecological mechanisms driving edge responses across edges between restored and natural forests will improve our ability to integrate restored areas into cross‐landscape management and, ultimately, improve our ability to manage landscapes for biodiversity conservation.     

Species abundance distribution and dynamics in two locally coupled communities

This study considered a model for species abundance dynamics in two local community (or islands) connected to a regional metacommunity. The model was analyzed using continuous probabilistic technique that employs Kolmogorov-Fokker-Planck forward equation to derive the probability density of the species abundance in the two local communities. Using this technique, we proposed a classification for the species abundance dynamics in the local communities. This classification was made based on such characteristics as immigration intensity, species representation in the metacommunity and the size of local communities. We further distinguished several different scenarios for species abundance dynamics using different ecological characteristics such as species persistence, extinction and monodominance in one or both local communities. The similarity of the species abundance distributions between the two local communities was studied using the correlation coefficient between species abundances in two local communities. The correlation is a function of migration rates between local communities and between local and metacommunity. Immigration between local communities drives the homogenization of the local communities, while immigration from the metacommunity will differentiate them. This community subdivision model provides useful insights for studying the effect of landscape fragmentation on species diversity.     

Disentangling the effects of plant species invasion and urban development on arthropod community composition

Urban development and species invasion are two major global threats to biodiversity. These threats often co‐occur, as developed areas are more prone to species invasion. However, few empirical studies have tested if both factors affect biodiversity in similar ways. Here we study the individual and combined effects of urban development and plant invasion on the composition of arthropod communities. We assessed 36 paired invaded and non‐invaded sample plots, invaded by the plant Antigonon leptopus, with half of these pairs located in natural and the other half in developed land‐use types on the Caribbean island of St. Eustatius. We used several taxonomic and functional variables to describe community composition and diversity. Our results show that both urban development and A. leptopus invasion affected community composition, albeit in different ways. Development significantly increased species richness and exponential Shannon diversity, while invasion had no effect on these variables. However, invasion significantly increased arthropod abundance and caused biotic homogenization. Specifically, uninvaded arthropod communities were distinctly different in species composition between developed and natural sites, while they became undistinguishable after A. leptopus invasion. Moreover, functional variables were significantly affected by species invasion, but not by urban development. Invaded communities had higher community‐weighted mean body size and the feeding guild composition of invaded arthropod communities was characterized by the exceptional numbers of nectarivores, herbivores, and detritivores. With the exception of species richness and exponential Shannon diversity, invasion influenced four out of six response variables to a greater degree than urban development did. Hence, we can conclude that species invasion is not just a passenger of urban development but also a driver of change.     

Fruiting phenology of fig trees in Kalinzu Forest,Uganda

The study determined the abundance and species composition of fig trees that fruited in the different forest types of Kalinzu Forest Reserve (KFR), Uganda. It also assessed the seasonal variations in abundance and species composition of the fig trees, the relationships between the fruiting patterns and rainfall and the figs’ inter‐ and intraspecific patterns of fruiting episodes. Sixteen fig species represented by 515 individuals were monitored monthly from December 2007 to January 2010. Most individuals and species that fruited were in the secondary forest types (the Musanga‐ and Parinari‐dominated secondary forests) and abundances of individuals of the different species were significantly associated with particular forest types. One colonizing species (Ficus sur) was the most abundant species that fruited and was mostly recorded in the secondary forests. Species composition and abundances of trees that fruited varied seasonally, and only the abundances of two canopy species (Ficus lingua and Ficus sansibarica) were significantly related with monthly rainfall. Most species experienced at least four fruiting phases, and F. sur displayed the longest episode covering 22 months. The results suggest that the past intensive logging in KFR promoted the regeneration of a diversity of fig species, and most species generally experience community‐wide asynchronous fruiting.     

Habitat preferences,seasonal abundance and diets of rodents in Alage,Southern Ethiopia

To understand habitat preferences, seasonal abundance and diets of rodents in wet and dry season surveys were conducted in Alage, Southern Ethiopia. Sherman and snap traps were used to capture rodents from the four habitats: bushland, Acacia woodland, maize and wheat farmlands. A total of 3312 trap nights, from the four trapping habitats, yielded 776 individuals that represented 11 species of rodents. The distribution of rodents varied between habitats and seasons. Wet season rodent abundance was 52.3% while in the dry season it was 47.7%. Seasonal differences in species abundance were insignificant. Bushland habitat had high wet and dry season abundances with 137 and 211 individuals, respectively. Abundance was low in maize farm (57 individuals) in the wet season and wheat farm (10 individuals) in the dry season. Stomach content composition analysis of snap‐trapped rodents from different habitats showed differences between species and across seasons. Six rodent species were recorded as pests on the farmlands in this study area. In conclusion, variation in habitat preferences and diet of rodents in different habitats and across seasons might be due to the role of ground cover and food sources.