Number Of Herbivore Species Research Articles

Spatiotemporal Variation of Urban Plant Diversity and above Ground Biomass in Haikou, China.

Understanding the drivers of urban plant diversity (UPD) and above ground biomass (AGB) in urbanized areas is critical for urban ecosystem services and biodiversity protection. The relationships between UPD and AGB have been investigated simultaneously. However, the drivers of UPD and AGB have been explored independently in tropical coastal areas at different time points. To fill this gap, we conducted a remote sensing interpretation, field plant plot surveys, and compiled socioeconomic and urban greening management survey data. We conducted spatial analyses to investigate the relationships among UPD and socioeconomic variables across different primary and secondary urban functional units (UFUs) in the tropical urban ecosystems of the coastal city of Haikou, China. The primary UFUs with the highest AGB were the recreation and leisure districts in 2015 and 2021. In 2015, AGB was mainly correlated with the number of herb species in undeveloped land and the districts of industry, business, recreation, and leisure. In 2021, AGB was affected primarily by the frequency of fertilizing, maintenance, and watering. Our study found that the relationship between UPD and AGB varied across time and space in Haikou. The plant diversity and AGB's response to human activities and socioeconomics appear to have a time-lag effect. These results provide new insights in understanding how management decisions affect urban vegetation and could be used to guide future urban green space planning in Haikou.

The bone collector: temporal patterns of bone-gnawing behaviour define osteophagia as a female prerogative in a large rodent

Calcium and phosphorous consumption is essential for bone development and maintenance throughout life, particularly to pregnant and lactating females. Bone consumption may provide mothers with the required supplemental amount of calcium and phosphorous. Osteophagia has been reported in a number of herbivore species as supplying such key mineral elements, although sound evidence is lacking for rodents. The diet of the crested porcupine is vegetarian and predominantly composed by roots and hypogeal storage organs. Gnawed bone residuals have often been observed in the surroundings of porcupine setts. This behaviour may have evolved to reduce the indefinite growth of incisor teeth, to increase calcium and phosphorous supply, or to fulfil both these functions. To clarify this issue, five setts were monitored for 3 years and bones in front of sett entries were counted and collected once a month. A total of 63 bones (mainly femurs and shins: 38.8%) was detected, mainly belonging to wild (46.03%) and domestic (28.57%) ungulates. The presence of gnawed bones in front of sett entries was recorded throughout the year, with a peak at the start of February. Camera-trapping data confirmed that areas surroundings house-farms, where most bones were probably collected, were only selected in the cold season. The peak of gnawed bone detection overlapped with the birth peak, suggesting that bones may be consumed by lactating females to increase the amount of minerals in their diet. This suggestion was further confirmed by the detection of no gnawed bones in front of the sett of the male-male pair. Porcupines are known to collect and gnaw bones in the surroundings of their setts, but ecological explanations and temporal patterns of this behaviour are unknown. We monitored five setts for 3 years, measuring and identifying gnawed bones in front of sett entries once a month. We then conducted an intensive camera-trapping session to monitor areas surrounding house-farms. Bone collection occurred throughout the year, with a peak in February, coinciding with the birth peak of this species. We therefore suggested that bone consumption could be a female prerogative, related to a supply of minerals in diet, as no gnawed bone was observed at the sett of a male-male pair.

Floristic Diversity Along An Altitudinal Gradient in Lakadmandi Beat of Kalatop Khajjiar Wildlife Sanctuary of District Chamba, Himachal Pradesh

A study was conducted to understand the floristic diversity along an altitudinal gradient with elevations varying from 1800-2400m above msl in Lakadmandi beat of Kalatop Khajjiar Wildlife Sanctuary in district Chamba, Himachal Pradesh during 2011. Total number of plant species was 81 belonging to 52 families and 76 genera. The dominant families were Asteraceae, Rosaceae, Pinaceae and Polygonaceae. The number of trees species was 6, 6 and 10 with the dominance of Quercus leucotrichophora, Cedrus deodara and Cedrus deodara at 1800-2000m, 2000-2200m and 2200-2400m elevation ranges respectively. The number of shrub species was 16, 13 and 23 with the dominance of Quercus leucotrichophora sapling, Sarcococca saligna and Sarcococca saligna at 1800-2000m, 2000-2200m and 2200-2400m elevations respectively. The number of herb species was 46, 46 and 58 at 1800-2000m, 2000-2200m and 2200-2400m elevation ranges respectively. On the basis of Importance Value Index (IVI), Valeriana jatamansii was the dominant herb at 2000-2200m and 2200-2400m elevation ranges respectively. The distribution pattern of most of plant species was contiguous at all altitudinal ranges. Index of diversity for herb species in these elevational ranges was 3.420, 3.568 and 3.250. Out of 40 medicinal plant species recorded from the area, 3 species i.e. Paris polyphylla, Podophyllum hexandrum and Taxus wallichiana fall in the category of threatened plants. The better conservation of natural resources can be done through promotion of community based conservation, ex-situ conservation through tissue culture, developing cultivation technologies and nurseries of medicinal plants and conducting of regular training on the procedure of medicinal plants collection and processing among the end users.

Assessment of Vegetation Along an Altitudinal Gradient in Khajrot Beat of Kalatop Khajjiar Wildlife Sanctuary of District Chamba, Himachal Pradesh

A study was conducted to assess the composition of vegetation along an altitudinal gradient with elevations varying from 1900-2300m above msl in Khajrot beat of Kalatop Khajjiar Wildlife Sanctuary in district Chamba, Himachal Pradesh during 2011. Total number of plant species was 105 belonging to 60 families and 95 genera. The dominant families were Asteraceae, Rosaceae, Polygonaceae, Lamiaceae and Pinaceae. The number of tree species at 1900-2100m and 2100-2300m elevation was 14 and 10 with the dominance of Picea smithiana at both the altitudes. The number of shrub species was 23 and 19 with the dominance of Sarcococca saligna at both the elevations. The number of herb species was 61 and 54 with the dominance of Valeriana jatamansii at 1900-2100m and 2100-2300m elevation ranges respectively. The distribution pattern of most of the plant species was contiguous in all the altitudinal ranges. Index of diversity for herb species in different elevation ranges was 3.301 and 3.334. Out of 50 medicinal plant species recorded from the area, 3 species i.e. Dioscorea deltoidea, Polygonatum verticillatum and Paris polyphylla fall in the category of threatened plants. The better conservation of natural resources can be done through promotion of community based conservation, ex-situ conservation through tissue culture, developing cultivation technologies and nurseries of medicinal plants and conducting of regular training on the procedure of medicinal plants collection and processing among the end users.

Plant Diversity Along an Altitudinal Gradient in Kalatop Beat of Kalatop Khajjiar Wildlife Sanctuary of District Chamba, Himachal Pradesh

Plant diversity study conducted at an altitudinal gradient varying from 1800-2400m above msl in Kalatop beat of the Sanctuary revealed that the total number of plant species was 142 belonging to 71 families and 127 genera. The dominant families were Asteraceae, Rosaceae, Fabaceae, Ranunculaceae and Polygonaceae. The number of trees species was 7, 9 and 12 with the dominance of Cedrus deodara at 1800-2000m, 2000-2200m and 2200-2400m elevation ranges respectively. The number of shrub species was 26, 27 and 24 with the dominance of Berberis lycium, Sarcococca saligna and Sarcococca saligna at 1800-2000m, 2000-2200m and 2200-2400m elevations respectively. The number of herb species was 59, 74 and 75 with the dominance of Bergenia ciliata, Pilea scripta and Valeriana jatamansii at 1800-2000m, 2000-2200m and 2200-2400m elevation ranges respectively. The distribution pattern of most of the plant species was contiguous in all altitudes. Index of diversity for herb species in these elevations ranges was 3.750, 3.674 and 3.472. Out of 63 medicinal plant species recorded from the area, 4 species viz; Podophyllum hexandrum, Taxus wallichiana, Polygonatum verticillatum and Zanthoxylum armatum fall in the threatened category. The better conservation of natural resources can be done through promotion of community based conservation, ex-situ conservation through tissue culture, developing cultivation technologies and nurseries of medicinal plants and conducting of regular training on the procedure of medicinal plants collection and processing among the end users.

Effects of local tree diversity on herbivore communities diminish with increasing forest fragmentation on the landscape scale.

Forest fragmentation and plant diversity have been shown to play a crucial role for herbivorous insects (herbivores, hereafter). In turn, herbivory-induced leaf area loss is known to have direct implications for plant growth and reproduction as well as long-term consequences for ecosystem functioning and forest regeneration. So far, previous studies determined diverging responses of herbivores to forest fragmentation and plant diversity. Those inconsistent results may be owed to complex interactive effects of both co-occurring environmental factors albeit they act on different spatial scales. In this study, we investigated whether forest fragmentation on the landscape scale and tree diversity on the local habitat scale show interactive effects on the herbivore community and leaf area loss in subtropical forests in South Africa. We applied standardized beating samples and a community-based approach to estimate changes in herbivore community composition, herbivore abundance, and the effective number of herbivore species on the tree species-level. We further monitored leaf area loss to link changes in the herbivore community to the associated process of herbivory. Forest fragmentation and tree diversity interactively affected the herbivore community composition, mainly by a species turnover within the family of Curculionidae. Furthermore, herbivore abundance increased and the number of herbivore species decreased with increasing tree diversity in slightly fragmented forests whereas the effects diminished with increasing forest fragmentation. Surprisingly, leaf area loss was neither affected by forest fragmentation or tree diversity, nor by changes in the herbivore community. Our study highlights the need to consider interactive effects of environmental changes across spatial scales in order to draw reliable conclusions for community and interaction patterns. Moreover, forest fragmentation seems to alter the effect of tree diversity on the herbivore community, and thus, has the potential to jeopardize ecosystem functioning and forest regeneration.

Shade Tree Diversity, Cocoa Pest Damage, Yield Compensating Inputs and Farmers' Net Returns in West Africa

Cocoa agroforests can significantly support biodiversity, yet intensification of farming practices is degrading agroforestry habitats and compromising ecosystem services such as biological pest control. Effective conservation strategies depend on the type of relationship between agricultural matrix, biodiversity and ecosystem services, but to date the shape of this relationship is unknown. We linked shade index calculated from eight vegetation variables, with insect pests and beneficial insects (ants, wasps and spiders) in 20 cocoa agroforests differing in woody and herbaceous vegetation diversity. We measured herbivory and predatory rates, and quantified resulting increases in cocoa yield and net returns. We found that number of spider webs and wasp nests significantly decreased with increasing density of exotic shade tree species. Greater species richness of native shade tree species was associated with a higher number of wasp nests and spider webs while species richness of understory plants did not have a strong impact on these beneficial species. Species richness of ants, wasp nests and spider webs peaked at higher levels of plant species richness. The number of herbivore species (mirid bugs and cocoa pod borers) and the rate of herbivory on cocoa pods decreased with increasing shade index. Shade index was negatively related to yield, with yield significantly higher at shade and herb covers<50%. However, higher inputs in the cocoa farms do not necessarily result in a higher net return. In conclusion, our study shows the importance of a diverse shade canopy in reducing damage caused by cocoa pests. It also highlights the importance of conservation initiatives in tropical agroforestry landscapes.

Analysis of plant diversity along an altitudinal gradient in Lippa- Asrang valley of cold desert in district Kinnaur, Himachal Pradesh

A study was conducted to understand the plant diversity along an altitudinal gradient with elevations varying from 2750 to 5000m above msl in Lippa – Asrang valley falling in cold desert area of Pooh sub division of district Kinnaur, Himachal Pradesh during 2007. The number of tree species at 2750-3200m and 3200-3650m elevations were 10 and 8 with the dominance of Cedrus deodara and Pinus wallichian respectively. The number of shrub species were 19, 17, 7 and 3 in the elevations of 2750-3200m, 3200-3650m, 3650-4100m and 4100-4550m respectively. Juniperus communis taking shape of the dominant shrub at 2750-3200 m, 3200-3650 m and 3650-4100m elevations. Rhododendron anthopogon was the dominant shrub at 4100-4550m elevation range. The number of herb species were 76, 73, 46, 39 and 33 at 2750-3200m, 3200-3650m, 3650-4100m, 4100-4550m and 4550-5000m elevational ranges respectively. On the basis of importance value index (IVI), Artemisia brevifolia, Heracleum candicans, Thymus linearis, Bergenia stracheyi and Bistorta affinis were the dominant herbs dotting different elevational ranges and distribution pattern of plant species was mostly contiguous in all the altitudes. Index of diversity for herb species in different elevational ranges was 3.89, 3.82, 3.47, 3.21 and 2.95. Out of 78 medicinal plant species as recorded from the area, 20 species fall in the category of threatened plants. The better conservation of natural resources can be well achieved through promotion of community based conservation stressing in-situ conservation through the establishment of nature reserves and ex-situ conservation through tissue culture, developing cultivation technologies and nurseries of medicinal plants and conducting regular trainings on the procedure of medicinal plants collection, processing amongst the end users/ the local people, traders and real stake holders.

Insects on urban plants: contrasting the flower head feeding assemblages on native and exotic hosts

Exotic plant species very often comprise a large proportion of urban floras. Because herbivorous insects depend on the presence of suitable host plants to maintain their populations, it is imperative to elucidate the relative importance of native and exotic hosts to understand the response of herbivorous guilds to urbanization. By using a plant-herbivore system composed of Asteraceae hosts and flower-head endophagous insects, we investigated whether the diversity and composition of herbivorous insects differs between native and exotic host-plant species in an urban environment. Although we found only seven exotic Asteraceae among the 30 species recorded, the overall abundance of exotics was considerably greater than that of native host plants. Overall, the exotic host species supported a small subset of the herbivore assemblage found on the native ones. The number of herbivore species per host species was significantly higher among the native plants, but we did not find a difference in herbivore abundance. Moreover, the higher taxonomic composition of herbivores on exotic Asteraceae was reduced, being composed of only three genera and two families from a total of 16 genera and six families of herbivores. These results provide support for the idea that plants outside of their original geographic distribution have lower loads of enemies than phylogenetically related native species. Our findings indicate that native host plants in urban areas play a critical role in supporting the native herbivorous insect fauna.

Native and Exotic Pests of Eucalyptus: A Worldwide Perspective

Eucalyptus species, native to Australia, Indonesia, the Philippines, and New Guinea, are the most widely planted hardwood timber species in the world. The trees, moved around the globe as seeds, escaped the diverse community of herbivores found in their native range. However, a number of herbivore species from the native range of eucalypts have invaded many Eucalyptus-growing regions in North America, Europe, Africa, Asia, and South America in the last 30 years. In addition, there have been shifts of native species, particularly in Africa, Asia, and South America, onto Eucalyptus. There are risks that these species as well as generalist herbivores from other parts of the world will invade Australia and threaten the trees in their native range. The risk to Eucalyptus plantations in Australia is further compounded by planting commercially important species outside their endemic range and shifting of local herbivore populations onto new host trees. Understanding the mechanisms underlying host specificity of Australian insects can provide insight into patterns of host range expansion of both native and exotic insects.

Comparison of lepidopteran larval communities among tree species in a temperate deciduous forest, Japan

Abstract 1. The enormous diversity of phytophagous insects in forest canopies is hypothesised to be supported by the number of herbivorous species per host tree species or host specificity. It is therefore necessary to examine the effect of host plant species on compositional changes in the herbivore communities.2. The lepidopteran larval communities were examined in the canopies of 10 tree species in a temperate deciduous forest of Japan. The phylogeny and leaf flush phenology of host plant species were taken into account as factors affecting the herbivore community assembly.3. Examination of seasonal changes in the larval community structures on each tree species showed that larval species richness, abundance, and evenness decreased significantly from spring to summer. Larval species richness and abundance were characterised by family‐level phylogenetic differences among tree species, whereas evenness was determined at a higher taxonomic level.4. Compositional changes in the larval communities among tree species showed a remarkable pattern, with a phylogenetic effect at a high taxonomic level in spring, similar to evenness, but a phenological effect in summer. This suggests that host specificity could support the lepidopteran larval diversity in spring.5. These results suggest that the differences in host utilisation of the herbivore, which reflects the phylogenetic effect of the host plants, can be important as a factor affecting the diversity of lepidopteran larval communities in temperate forests.

Breeding habitat selection by houbara bustard(Chlamydotis [undulata] macqueenii) in Mori, Xinjiang, China

The breeding habitat selection by houbara bustards in Mori, Xinjiang, China during the breeding seasons from April to June 1998—2000 was studied. Most of habitats chosen for breeding were short sub-shrubby and open areas close to high bushy patches. The nesting females clearly prefer low covered areas and avoid densely covered and high vegetation sites. The number of herb species was significantly smaller at nest sites than at randomly selected sites. Only the distance to the closest fox den contributed the most to discrimination between successful and predated nests. The average distance to the closest fox den was significantly longer at successful nests than at depredated nests. Vegetative density, plant species richness, topography and distance to the closest fox den are possibly the most important factors that determined the nest sites selection of houbara bustard. The displaying males clearly prefer low covered areas and avoid densely covered and high vegetation sites. The vegetation density and number of plant species at display sites was significantly lower than that at randomly selected sites. The average distance to the closest bushy patch was significantly shorter at display sites than at random sites. Plant species richness, vegetative density, vegetative cover and distance to the bushy patches are possibly the most important factors for the display sites selection of houbara bustard.

Patterns of Plant Diversity in Overbrowsed Primary and Mature Secondary Hemlock-Northern Hardwood Forest Stands

ROONEY, T. P. AND W. J. DRESS. (Department of Biology, Indiana University of Pennsylvania, Indiana PA 15705). Patterns of plant diversity in overbrowsed primary and mature secondary hemlock-northern hardwood forest stands. J. Torrey Bot. Soc. 124: 43-51. 1997.-Many studies report that herbaceous species diversity is higher in primary forest than mature secondary forests, but this pattern has not yet been demonstrated in forests overbrowsed by white-tailed deer. We compared the diversity of herbaceous and tree seedling species in 5 primary and 5 mature secondary riparian zone forest stands in northwestern Pennsylvania, a region which has been overpopulated with white-tailed deer for the past 65 years. We sampled study plots with 16 1 -M2 quadrats and recorded herb and tree seedling species presence and abundance. At the -rM2 scale, primary forest sites had significantly more tree seedling species per quadrat but the number of herb species per quadrat in primary and secondary forest sites was not significantly different. At the 2.25 ha scale, primary forest sites had significantly higher herb and tree seedling richness than secondary sites. Herbs and tree seedlings also exhibited significantly greater evenness in primary sites than secondary sites. There was considerable species composition overlap between primary and secondary sites. Tsuga canadensis, Fagus grandifolia, and Oxalis acetosella had a significantly higher frequency of occurrence and significantly greater abundance in primary forest sites, whereas Prunus serotina and Erythronium americanum had a significantly higher frequency of occurrence and significantly greater abundance in secondary forest sites. Acer rubrum was also significantly more abundant in secondary growth sites. We hypothesize that the trend towards greater diversity in primary forest plots is the result of these stands experiencing levels of disturbance closer to the historic disturbance regime.

Understorey plants as indicators of site productivity inPinus sylvestrisL. stands

The capabilities of understorey plant species to indicate site productivity, as expressed by site index (H100), were examined using data from 222 sample plots from mature stands of Pinus sylvestris L. in southern Finland. The number of herb species was relatively strongly correlated with site index (r =0.81). Also, the presence of 20–30 species indicated site index well. The link between understorey vegetation and site productivity was primarily based on the distribution patterns of these indicators. In contrast, species cover was poorly related to site productivity. In regressions of species cover on site index, only ten species achieved r 2 of 40% or more. No good indicators existed where site index was less than 21 m. The inclusion of soil deposit types (soil texture) in the prediction model compensated for the poor prediction power of understorey plants on sites of low productivity and increased the accuracy of site productivity estimation by approximately 15%. The estimation did not improve when temp...

Searching for weed biocontrol agents—when to move on?

‘Classical’ biological control for an exotic weed requires time‐consuming and expensive surveys for natural enemies in the weed's native range. We advocate the use of rarefaction curves to improve survey efficiency, i.e. to determine the minimum sampling effort for discovering most of the potential control agents actually occurring in the weed's native range. Rarefaction (dilution) curves can be used to estimate the number of herbivore species expected on a given number of plants, at sampling sites or regions, using presence/absence data and species frequencies. An analysis of the shape of the rarefaction curves will therefore indicate (a) which sites possibly contain more undiscovered herbivore species and (b) whether sampling new sites is more likely to reveal further herbivores. This approach is illustrated with two case studies of insect surveys, of root and flower head feeders on Centaurea maculosa (Asteraceae) in Europe and for flower head feeders of various Asteraceae in Brazil. Finally, we conside...

Time and the Number of Herbivore Species: The Pests of Sugarcane

Previous analyses have established that host species range in the most important determinant of plant— and animal—associated parasite species richness, and that the age of a host species within a region is, at most, much less important in determining this richness. However, these previous analyses were not able to completely rule out age as a cause, because the available host age estimations were crude and few host groups were available for comparison. This paper examines the arthropod pests of sugarcane (Saccharum officinarum) in 51 regions for which dates of introduction, areas in cultivation, and associated pest data are available. The sugarcane data are more complete and extensive than those for previously investigated host—parasite associations, and they make possible a more detailed analysis of the causes of species richness. Multiple regression analyses of these data cannot identify time to have any measurable influence upon the species richness of sugarcane pests. This implies pest species accumulation to reach an asymptote within, at most, a few hundred years. The asymptote is set by the geographic range of host species. The results of this study are consistent with those of four other analyses of host—parasite associations. We suggest sufficient evidence has accumulated to justify abandoning nonasymptotic species accumulation models (the "time) and "stability—time" hypotheses), at least for parasite communities. We caution against invoking "time" hypotheses for the explanation of diversity variation in other ecological systems where the influence of area and immigration rates cannot be dealt with. The "time" hypothesis also often involves virtually untestable assumptions about habitat constancy over very long periods of time.

Organization of a Plant‐Arthropod Association in Simple and Diverse Habitats: The Fauna of Collards (Brassica Oleracea)

Collards were grown at Ithaca, New York, in two experimental habitats: pure stands and single rows that were bounded on each side by diverse, meadow vegetation. The arthropods associated with these plants were sampled on 20 dates over a 3—year period. The status of the herbivore species was measured by their rank in biomass in each sample. The two most prominent species, Phyllotreta cruciferae and Pieris rapae, maintained high status throughout the investigation, but another important species, Brevicoryne brassicae, was absent for an entire season. Pit feeders usually formed the most important herbivore guild. Nevertheless, the guild spectrum, which describes the functional structure of the fauna, varied widely in time and space. The size distributions of species and of individuals were both highly skewed toward the smaller sizes. Herbivore loads, the mean biomass of herbivores per 100 g of consumable foliage, were consistently higher in the pure stands. Moreover, herbivore loads varied significantly with season in each experimental habitat. Both the number of herbivore species and the diversity of the herbivore load were greater in the diverse habitat. Biomass was more heavily concentrated among the prominent herbivores in the pure stands; increased dominance, rather than differences in species richness, appeared to be the major cause for the lower herbivore diversity in this habitat. The diversity of predators and parasitoids was higher in the pure stands. Most of the abundant species found on collards shared a similar narrow range of hosts. As a result the species in this core group of herbivores and parasitoids were regularly associated with each other. Predators and the less abundant herbivores tended to be less specialized and served to link the collard association with the surrounding community. Plant—arthropod associations are representative of component communities, well—integrated systems that form portions of larger compound communities. This distinction facilitates the analysis of community structure. Microclimates and the effectiveness of "enemies" did not appear to differ sufficiently in the two experimental habitats to account for the observed differences in the herbivore load. The results suggest a new proposition, the resource concentration hypothesis, which states that herbivores are more likely to find and remain on hosts that are growing in dense or nearly pure stands; that the most specialized species frequently attain higher relative densities in simple environments; and that, as a result, biomass tends to become concentrated in a few species, causing a decrease in the diversity of herbivores in pure stands.