Mast seeding promotes evolution of scatter-hoarding

Many plant species worldwide are dispersed by scatter-hoarding granivores: animals that hide seeds in numerous, small caches for future consumption. Yet, the evolution of scatter-hoarding is difficult to explain because undefended caches are at high risk of pilferage. Previous models have attempted to solve this problem by giving cache owners large advantages in cache recovery, by kin selection, or by introducing reciprocal pilferage of ‘shared’ seed resources. However, the role of environmental variability has been so far overlooked in this context. One important form of such variability is masting, which is displayed by many plant species dispersed by scatterhoarders. We use a mathematical model to investigate the influence of masting on the evolution of scatter-hoarding. The model accounts for periodically varying annual seed fall, caching and pilfering behaviour, and the demography of scatterhoarders. The parameter values are based mostly on research on European beech ( Fagus sylvatica ) and yellow-necked mice ( Apodemus flavicollis ). Starvation of scatterhoarders between mast years decreases the population density that enters masting events, which leads to reduced seed pilferage. Satiation of scatterhoarders during mast events lowers the reproductive cost of caching (i.e. the cost of caching for the future rather than using seeds for current reproduction). These reductions promote the evolution of scatter-hoarding behaviour especially when interannual variation in seed fall and the period between masting events are large. This article is part of the theme issue ‘The ecology and evolution of synchronized seed production in plants’.

Seed Sowing Robot

Agriculture is the most important field for human beings. It is the backbone of our country's economic system. Equipment that needs less human effort and time with less price of implementation is way needed for fulfilment within the agricultural trade. Project work is focused on the seed sowing process and the design of a four-wheel-drive robot that does the work of seed sowing in plowed agricultural land avoiding the human effort by tracing the path and sowing seeds and tried to solve the problems related to agriculture. Seed sowing robot consists of battery-powered wheels, a DC motor inbuilt in these wheels, an Arduino Uno is useful for controlling the robotic activities. The Robot can detect the obstacle very easily with the help of an ultrasonic sensor. In every complete rotation of the rotating wheel, there’s a seed fall from the seed drum and performs seed sowingoperation. Keywords: Agriculture, Farmer, Seed, Robot

Patterns of Phenological Characteristics of Important Tree Species of Kumaun Himalaya

Phenology is one of the simplest and most effective study to understanding the role of climate change in recent scenario. A number of biotic and abiotic drivers controlled the timing and duration of various phenophases in same or different species. Temperature, rainfall and photoperiod are key drivers which adversely affect the phenology of woody plant. The study sites were conductedat 413 and 2345m elevation in Nainital forest division of Kumaun Himalaya. The phenological study were carried out onShores robusta, Mallotus philippinensis, Pinus roxburghii, Myrica esculenta,Quercus leucotrichophora and Rhododendron arboreum. The phenological observations were made at 15 days interval for low activity period and weekly in the periods of high activity. Phenological records were made for four phenophases, viz., leafing, leaf drop, flowering and seed fall.The leaf fall in S. robusta started from March 2nd week and was complete by the end of April. In M. philippinensis the fruiting commenced from the beginning of December and seed fall was complete by the 3rd week of April. In M. esculenta male flowers appear from August end and flowering was complete by October end.In R. arboreum seed dispersal started from February end and all the capsules had opened by mid-March. It is apparent from the present study that the phenological events of species controlled/shifted due to climatic irregularities and temperaturerise and these phenomena showed worldwide. Microclimatic condition alsoresponsible for controlling/shifting the phenological patterns of same or different species.

Effects of Skidding Operations after Tree Harvesting and Soil Scarification by Felled Trees on Initial Seedling Emergence of Spanish Black Pine (Pinus nigra Arn. ssp. salzmannii)

Skidding operations are thought to have negative impacts on soil emergence because they may increase soil compaction and reduce vegetation cover and the soil’s organic matter content. We investigated whether and to what extent tree harvesting and subsequent skidding initially altered seedling emergence in two Mediterranean forests of Pinus nigra Arn. ssp. salzmannii (Spanish black pine) in the Cuenca Mountains (Spain). Our main objective was to compare the Spanish black pine seedling emergence rate among skid trails, soil areas scarified by felled trees, and areas undisturbed next to harvest operations. In addition, we selected an unmanaged stand as reference, in order to look for evidence of seedling emergence under natural conditions. We measured Spanish black pine seed fall and seedling emergence immediately after harvest operations in two locations in the Cuenca Mountains (Palancares and Majadas forests), which are typical forests in Cuenca Mountains. The results showed that the Palancares site presented higher seed fall in comparison to the Majadas site. In addition, seed fall was higher in the unmanaged stand, as we recorded a higher tree density in this site in comparison to harvested stands (Palancares and Majadas). Furthermore, our results demonstrated differences in seedling emergence between lower elevation drier Palancares and higher elevation wetter Majadas and relative differences in seedling emergence among skid trail, scarified, and undisturbed harvested areas. Finally, the unmanaged stand presented the highest seedling emergence in comparison to scarified, compacted, and non-disturbed harvested areas. Overall, the results suggest a short-term impact of skidding on seedling emergence, which should be considered for future management guidelines of Spanish black pine in the Mediterranean climate.

Successful Ecological Regeneration of Opencast Coal Mine Spoils through Forestation: From Cradle to Grove

The reclamation of surface (opencast) coal mines is not always successful; there remains a legacy of degraded land that burdens local communities. This article evaluates a community-oriented, low-cost means of geoecological regeneration, the “Cradle for Nature” strategy, which uses mosaic tree planting to foster positive natural ecological processes. Results show that, while the autocompaction of minestones quickly raises soil densities to levels hostile to plant growth, forestation helps moderate soil densities. Weathering concentrates metals in minestones, but 14 years of forestation reduced the loadings of five metals by 35–52%. Twenty years of forestation doubled soil organic carbon to >7%; increased bacilli from 7% to 46%; actinomycetes from 10% to 26%; and soil microbe counts 12–15 times, especially in tree plantings treated with fertiliser. Soils under trees also supported a significantly greater earthworm biomass than under grass but, while open-canopy plantings had increased ground flora biodiversity, closed-canopy plantings had lower diversity and biomass. Following closure to grazing, ground biomass increased sevenfold. Young trees act as bird perches and significantly increase seed fall. Small mammal biomass and biodiversity increases after tree planting and higher predators appear. Varteg’s constructed forest provides an effective “cradle” for an emergent geoecological system and its habitat mosaic maximises biodiversity.

Mast seeding promotes evolution of scatter-hoarding

ABSTRACTMany plant species worldwide are dispersed by scatterhoarding granivores: animals that hide seeds in numerous, small caches for future consumption. Yet, the evolution of scatterhoarding is difficult to explain because undefended caches are at high risk of pilferage. Previous models have attempted to solve this problem by giving cache owners unrealistically large advantages in cache recovery, by kin selection (but individuals that cache and those that pilfer are usually unrelated), or by introducing reciprocal pilferage of “shared” seed resources. However, the role of environmental variability has been so far overlooked in this context. One important form of such variability is masting, which is displayed by many plant species dispersed by scatterhoarders. We use a mathematical model to investigate the influence of masting on the evolution of scatter-hoarding. The model accounts for periodically varying annual seed fall, caching and pilfering behavior, and the demography of scatterhoarders. Masting, through its effects on population density, reduces cache pilferage and lowers the reproductive cost of caching (i.e. the cost of caching for the future rather than using seeds for current reproduction). These reductions promote the evolution of scatter-hoarding behavior especially when interannual variation in seed fall and the period between masting events are high.

Seasonal litterfall composition and carbon and nitrogen returns in New Zealand shrubland

Mānuka–kānuka shrubland is an important carbon (C) sink in New Zealand, yet little is known about C cycling within these systems. The objective of our work was to assess seasonal litterfall rates, composition, and C and nitrogen (N) inputs in mixed mānuka (Leptospermum scoparium J.R. Forst & G. Forst.) and kānuka (Kunzea ericoides var. ericoides (A.Rich) J.Thompson) stands. Litterfall was collected for 2years at Tongariro National Park (NP) and Stoney Creek, Wairarapa (SC), separated into leaf, twig, bark, seed and ‘other’, and the C and N content of each component measured. Total litterfall was between 3557 and 4443kgha–1year–1, of which leaf material contributed 46–67%. Litterfall peaked during spring–summer months at both sites, and the overall litterfall rate was greater (P < 0.001) at SC than NP. Litterfall at SC contained greater (P < 0.001) amounts of ‘other’ due to higher undergrowth contributions, and also greater seed fall (P < 0.001), possibility due to the lower altitude at SC. The proportion of leaf material in litterfall also peaked during summer (P < 0.001). C inputs in the total litter were 1941–2448kgCha–1year–1 and N inputs ranged between 28 and 37kgNha–1year–1. There was little seasonal difference in C and N contents and the majority of both C and N inputs in litterfall were in the leaf material (P < 0.001). C inputs peaked during summer, but N inputs were closely aligned with total litterfall maximums during spring–summer. The leaf:wood ratio was 1.9 at both sites, indicating litter quality was consistent at both stands, regardless of differences in composition. Although the sites had similar rainfall and shrub ages, the rate of total litterfall differed, reflecting the potentially site-specific nature of litterfall in mānuka–kānuka shrubland. Further work is needed assessing litterfall and degradation rates across New Zealand to establish if mānuka–kānuka shrublands would remain carbon sinks under climate change.

Response of Phenological Events of Aesculus indica Colebr. to Climate Change Along an Altitudinal Gradient in Kumaun Himalaya, Uttarakhand

The present study investigated the timing and duration of phenological events of A. indica in different elevational range Kumaun Himalayan forest. A total of four sites at elevation ranging between 1,900m and 2,200m were selected and at each site 10 s were marked for observations. The phenological events, i.e. leaf bud formation, leaf bud busting, leafing, flowering bud formation, flowering bud busting, flowering, fruit/seed formation, seed fall and leaf fall were monitored. Phenological duration and asynchrony of these phenophases were determined at 10 day intervals and every 2-3 day intervals during the period of peak activities. The minimum length displayed leaf bud formation (44 days) and maximum by leaf fall (86 days) across the elevation. The environmental conditions, particularly temperature, affected the phenological patterns of A. indica. The leaf bud busting activity of A. indica was 51 days. Flowering activity started on May 1st and was extended over 76 days until July 15th. Seed fall activity was extended over 66 day across elevations. ANOVA showed the longevity of phenophases were varied significantly respective to elevations (p<0.05). Our observation showed that all the phenological events of A. indica appear early at lower (1900 m) and are delayed with increasing elevation. All corresponding phenological events were earlier at lower elevations because the optimum (9.0 to 19.5°C) is met earlier in these conditions.

Plant Attributes that Drive Dispersal and Establishment Limitation in Tropical Agricultural Landscapes

Factors that influence tropical-forest regeneration have been of interest across the tropics. We tested the degree of dispersal and establishment limitation of pioneer and non-pioneer tree species with different dispersal modes and seed sizes, using data on both seed fall and seedling establishment in primary forest, secondary forest, and pasture excluded from livestock. The study took place in a lowland tropical rain forest in southeastern Mexico. To calculate dispersal and establishment limitation, we used a density-weighted index that considers: (1) whether a seed or seedling of a given species has arrived in the sample area; and (2) the fraction of seeds or seedlings contributed by a given species relative to the total number of seeds or seedlings arriving at a sampling station. Dispersal limitation of non-pioneer species and animal-dispersed species decreased with succession. The secondary forest had less dispersal limitation for wind-dispersed pioneers than pasture, resulting in a dense aggregation of species with seeds dispersed by wind. Overall, establishment limitation differed between animal-dispersed and wind-dispersed species in the primary forest, and was negatively correlated with seed size. The low capacity of most species to arrive, germinate, and establish as seedlings in pastures slows succession back to forest. To overcome barriers to natural succession in pastures, transplanting seedlings of non-pioneer species is suggested because most of them show high dispersal and establishment limitation.