Mountain bluebird
The mountain bluebird is a medium-sized bird weighing about 30 g with a length from 16–20 cm. They have black eyes. Adult males are bright turquoise-blue and somewhat lighter underneath. Adult females have duller blue wings and tail, grey breast, grey crown and back. In fresh fall plumage, the female's throat and breast are tinged with red-orange, brownish near the flank contrasting with white tail underparts, their call is a thin'few'. It is the state bird of Nevada, it is an omnivore and it can live 6 to 10 years in the wild. It eats spiders, grasshoppers and other insects, small fruits; the mountain bluebird is a relative of the western bluebirds. These birds hover over the ground and fly down to catch insects flying from a perch to catch them; the first technique takes up to 8 times the energy than waiting. They eat insects and berries, they may forage in flocks in winter, when they eat grasshoppers. Mountain Bluebirds will come to a platform feeder with berries, or peanuts, their breeding habitat is open country across western North America, including mountainous areas, as far north as Alaska.
They nest in nest boxes. In remote areas, these birds are less affected by competition for natural nesting locations than other bluebirds. Mountain bluebirds are a monogamous breed; the male can be seen singing from bare branches. The singing takes place right at dawn. Females build the nests themselves. Eggs are unmarked, sometimes white; the clutch size is five eggs. Young may have some down. Incubation last 14 days and the young will take about 21 days before they leave the nest. Both males and females fiercely protect the nest; the mountain bluebird is the state bird of Nevada. Mountain bluebirds are cavity nesters and can become partial to a nest box if they have raised a clutch, they may reuse the same nest, though not always. Mountain bluebirds will not abandon a nest if human activity is detected close at the nest; because of this, they can be banded while they are still in the nest. Mountain Bluebirds are common, but populations declined by about 26% between 1966 and 2014, according to the North American Breeding Bird Survey.
Partners in Flight estimates the global breeding population of 4.6 million, with 80% spending some part of the year in the U. S. 20% breeding in Canada, 31% wintering in Mexico. The species rates an 8 out of 20 on the Continental Concern Score. Mountain Bluebird is a U. S.-Canada Stewardship species, is not on the 2014 State of the Birds Watch List. These bluebirds benefited from the westward spread of logging and grazing in the late nineteenth and early twentieth centuries, when the clearing of forest created open habitat for foraging; the subsequent waning of these industries, coupled with the deliberate suppression of wildfires, led to a dwindling of open acreage in the West and the decline of the species. More as land-use practices have stabilized, so have Mountain Bluebird populations. Construction of nest boxes in suitable habitat has provided a population boost. Populations are declining in areas where trees are too small to provide natural nesting cavities, where forest and agricultural management practices have reduced the availability of suitable nest sites.
Among birds that nest in cavities but can’t excavate them on their own, competition is high for nest sites. Mountain and more Eastern bluebirds compete for nest boxes where their ranges overlap. House Sparrows, European Starlings, House Wrens compete fiercely with bluebirds for nest cavities. Western bluebird Eastern bluebird All About Birds: Mountain Bluebird, Cornell Lab of Ornithology The Condor, Vol. 83, No. 3, pp. 252–255 Mountain Bluebird Information and Awareness North American Bluebird Society "Mountain bluebird media". Internet Bird Collection. Mountain bluebird photo gallery at VIREO
Seedling
A seedling is a young plant sporophyte developing out of a plant embryo from a seed. Seedling development starts with germination of the seed. A typical young seedling consists of three main parts: the radicle, the hypocotyl, the cotyledons; the two classes of flowering plants are distinguished by their numbers of seed leaves: monocotyledons have one blade-shaped cotyledon, whereas dicotyledons possess two round cotyledons. Gymnosperms are more varied. For example, pine seedlings have up to eight cotyledons; the seedlings of some flowering plants have no cotyledons at all. These are said to be acotyledons; the plumule is the part of a seed embryo that develops into the shoot bearing the first true leaves of a plant. In most seeds, for example the sunflower, the plumule is a small conical structure without any leaf structure. Growth of the plumule does not occur; this is epigeal germination. However, in seeds such as the broad bean, a leaf structure is visible on the plumule in the seed; these seeds develop by the plumule growing up through the soil with the cotyledons remaining below the surface.
This is known as hypogeal germination. Dicot seedlings grown in the light develop short hypocotyls and open cotyledons exposing the epicotyl; this is referred to as photomorphogenesis. In contrast, seedlings grown in the dark develop long hypocotyls and their cotyledons remain closed around the epicotyl in an apical hook; this is referred to as skotomorphogenesis or etiolation. Etiolated seedlings are yellowish in color as chlorophyll synthesis and chloroplast development depend on light, they will turn green when treated with light. In a natural situation, seedling development starts with skotomorphogenesis while the seedling is growing through the soil and attempting to reach the light as fast as possible. During this phase, the cotyledons are closed and form the apical hook to protect the shoot apical meristem from damage while pushing through the soil. In many plants, the seed coat still covers the cotyledons for extra protection. Upon breaking the surface and reaching the light, the seedling's developmental program is switched to photomorphogenesis.
The cotyledons open upon contact with light and become green, forming the first photosynthetic organs of the young plant. Until this stage, the seedling lives off the energy reserves stored in the seed; the opening of the cotyledons exposes the shoot apical meristem and the plumule consisting of the first true leaves of the young plant. The seedlings sense light through the light receptors cryptochrome. Mutations in these photo receptors and their signal transduction components lead to seedling development, at odds with light conditions, for example seedlings that show photomorphogenesis when grown in the dark.. Once the seedling starts to photosynthesize, it is no longer dependent on the seed's energy reserves; the apical meristems give rise to the root and shoot. The first "true" leaves expand and can be distinguished from the round cotyledons through their species-dependent distinct shapes. While the plant is growing and developing additional leaves, the cotyledons senesce and fall off. Seedling growth is affected by mechanical stimulation, such as by wind or other forms of physical contact, through a process called thigmomorphogenesis.
Temperature and light intensity interact. A photoperiod shorter than 14 hours causes growth to stop, whereas a photoperiod extended with low light intensities to 16 h or more brings about continuous growth. Little is gained by using more than 16 h of low light intensity once seedlings are in the free growth mode. Long photoperiods using high light intensities from 10,000 to 20,000 lumens/m² increase dry matter production, increasing the photoperiod from 15 to 24 hours may double dry matter growth; the effects of carbon dioxide enrichment and nitrogen supply on the growth of white spruce and trembling aspen were investigated by Brown and Higginbotham. Seedlings were grown in controlled environments with ambient or enriched atmospheric CO2 and with nutrient solutions with high and low N content. Seedlings were harvested and measured at intervals of less than 100 days. N supply affected biomass accumulation and leaf area of both species. In white spruce only, the root weight ratio was increased with the low-nitrogen regime.
CO2 enrichment for 100 days increased the leaf and total biomass of white spruce seedlings in the high-N regime, RWR of seedlings in the medium-N regime, root biomass of seedlings in the low-N regime. First-year seedlings have high mortality rates, drought being the principal cause, with roots having been unable to develop enough to maintain contact with soil sufficiently moist to prevent the development of lethal seedling water stress. Somewhat paradoxically, Eis observed that on both mineral and litter seedbeds, seedling mortality was greater in moist habitats than in dry habitats, he commented that in dry habitats after the first growing season surviving seedlings appeared to have a much better chance of continued survival than those in moist or wet habitats, in which frost heave and competition from lesser vegetation became major factors in years. The annual mortality docu
Mammal
Mammals are vertebrate animals constituting the class Mammalia, characterized by the presence of mammary glands which in females produce milk for feeding their young, a neocortex, fur or hair, three middle ear bones. These characteristics distinguish them from reptiles and birds, from which they diverged in the late Triassic, 201–227 million years ago. There are around 5,450 species of mammals; the largest orders are the rodents and Soricomorpha. The next three are the Primates, the Cetartiodactyla, the Carnivora. In cladistics, which reflect evolution, mammals are classified as endothermic amniotes, they are the only living Synapsida. The early synapsid mammalian ancestors were sphenacodont pelycosaurs, a group that produced the non-mammalian Dimetrodon. At the end of the Carboniferous period around 300 million years ago, this group diverged from the sauropsid line that led to today's reptiles and birds; the line following the stem group Sphenacodontia split off several diverse groups of non-mammalian synapsids—sometimes referred to as mammal-like reptiles—before giving rise to the proto-mammals in the early Mesozoic era.
The modern mammalian orders arose in the Paleogene and Neogene periods of the Cenozoic era, after the extinction of non-avian dinosaurs, have been among the dominant terrestrial animal groups from 66 million years ago to the present. The basic body type is quadruped, most mammals use their four extremities for terrestrial locomotion. Mammals range in size from the 30–40 mm bumblebee bat to the 30-meter blue whale—the largest animal on the planet. Maximum lifespan varies from two years for the shrew to 211 years for the bowhead whale. All modern mammals give birth to live young, except the five species of monotremes, which are egg-laying mammals; the most species-rich group of mammals, the cohort called placentals, have a placenta, which enables the feeding of the fetus during gestation. Most mammals are intelligent, with some possessing large brains, self-awareness, tool use. Mammals can communicate and vocalize in several different ways, including the production of ultrasound, scent-marking, alarm signals and echolocation.
Mammals can organize themselves into fission-fusion societies and hierarchies—but can be solitary and territorial. Most mammals are polygynous. Domestication of many types of mammals by humans played a major role in the Neolithic revolution, resulted in farming replacing hunting and gathering as the primary source of food for humans; this led to a major restructuring of human societies from nomadic to sedentary, with more co-operation among larger and larger groups, the development of the first civilizations. Domesticated mammals provided, continue to provide, power for transport and agriculture, as well as food and leather. Mammals are hunted and raced for sport, are used as model organisms in science. Mammals have been depicted in art since Palaeolithic times, appear in literature, film and religion. Decline in numbers and extinction of many mammals is driven by human poaching and habitat destruction deforestation. Mammal classification has been through several iterations since Carl Linnaeus defined the class.
No classification system is universally accepted. George Gaylord Simpson's "Principles of Classification and a Classification of Mammals" provides systematics of mammal origins and relationships that were universally taught until the end of the 20th century. Since Simpson's classification, the paleontological record has been recalibrated, the intervening years have seen much debate and progress concerning the theoretical underpinnings of systematization itself through the new concept of cladistics. Though field work made Simpson's classification outdated, it remains the closest thing to an official classification of mammals. Most mammals, including the six most species-rich orders, belong to the placental group; the three largest orders in numbers of species are Rodentia: mice, porcupines, beavers and other gnawing mammals. The next three biggest orders, depending on the biological classification scheme used, are the Primates including the apes and lemurs. According to Mammal Species of the World, 5,416 species were identified in 2006.
These were grouped into 153 families and 29 orders. In 2008, the International Union for Conservation of Nature completed a five-year Global Mammal Assessment for its IUCN Red List, which counted 5,488 species. According to a research published in the Journal of Mammalogy in 2018, the number of recognized mammal species is 6,495 species included 96 extinct; the word "mammal" is modern, from the scientific name Mammalia coined by Carl Linnaeus in 1758, derived from the Latin mamma. In an influential 1988 paper, Timothy Rowe defined Mammalia phylogenetically as the crown group of mammals, the clade consisting of the most recent common ancestor of living monotremes and therian m
Forest
A forest is a large area dominated by trees. Hundreds of more precise definitions of forest are used throughout the world, incorporating factors such as tree density, tree height, land use, legal standing and ecological function. According to the used Food and Agriculture Organization definition, forests covered 4 billion hectares or 30 percent of the world's land area in 2006. Forests are the dominant terrestrial ecosystem of Earth, are distributed around the globe. Forests account for 75% of the gross primary production of the Earth's biosphere, contain 80% of the Earth's plant biomass. Net primary production is estimated at 21.9 gigatonnes carbon per year for tropical forests, 8.1 for temperate forests, 2.6 for boreal forests. Forests at different latitudes and elevations form distinctly different ecozones: boreal forests near the poles, tropical forests near the equator and temperate forests at mid-latitudes. Higher elevation areas tend to support forests similar to those at higher latitudes, amount of precipitation affects forest composition.
Human society and forests influence each other in both negative ways. Forests serve as tourist attractions. Forests can affect people's health. Human activities, including harvesting forest resources, can negatively affect forest ecosystems. Although forest is a term of common parlance, there is no universally recognised precise definition, with more than 800 definitions of forest used around the world. Although a forest is defined by the presence of trees, under many definitions an area lacking trees may still be considered a forest if it grew trees in the past, will grow trees in the future, or was designated as a forest regardless of vegetation type. There are three broad categories of forest definitions in use: administrative, land use, land cover. Administrative definitions are based upon the legal designations of land, bear little relationship to the vegetation growing on the land: land, designated as a forest is defined as a forest if no trees are growing on it. Land use definitions are based upon the primary purpose.
For example, a forest may be defined as any land, used for production of timber. Under such a land use definition, cleared roads or infrastructure within an area used for forestry, or areas within the region that have been cleared by harvesting, disease or fire are still considered forests if they contain no trees. Land cover definitions define forests based upon the type and density of vegetation growing on the land; such definitions define a forest as an area growing trees above some threshold. These thresholds are the number of trees per area, the area of ground under the tree canopy or the section of land, occupied by the cross-section of tree trunks. Under such land cover definitions, an area of land can only be known as forest if it is growing trees. Areas that fail to meet the land cover definition may be still included under while immature trees are establishing if they are expected to meet the definition at maturity. Under land use definitions, there is considerable variation on where the cutoff points are between a forest and savanna.
Under some definitions, forests require high levels of tree canopy cover, from 60% to 100%, excluding savannas and woodlands in which trees have a lower canopy cover. Other definitions consider savannas to be a type of forest, include all areas with tree canopies over 10%; some areas covered in trees are defined as agricultural areas, e.g. Norway spruce plantations in Austrian forest law when the trees are being grown as Christmas trees and below a certain height; the word forest comes from Middle English, from Old French forest "forest, vast expanse covered by trees". A borrowing of the Medieval Latin word foresta "open wood", foresta was first used by Carolingian scribes in the Capitularies of Charlemagne to refer to the king's royal hunting grounds; the term was not endemic to Romance languages. The exact origin of Medieval Latin foresta is obscure; some authorities claim the word derives from the Late Latin phrase forestam silvam, meaning "the outer wood". Frankish *forhist is attested by Old High German forst "forest", Middle Low German vorst "forest", Old English fyrhþ "forest, game preserve, hunting ground", Old Norse fýri "coniferous forest", all of which derive from Proto-Germanic *furhísa-, *furhíþija- "a fir-wood, coniferous forest", from Proto-Indo-European *perkwu- "a coniferous or mountain forest, wooded height".
Uses of the word "forest" in English to denote any uninhabited area of non-enclosure are now considered archaic. The word was introduced by the Norman rulers of England as a legal term denoting an uncultivated area set aside for hunting by feudal nobility; these hunting forests were not neces
Ecosystem
An ecosystem is a community of living organisms in conjunction with the nonliving components of their environment, interacting as a system. These biotic and abiotic components are linked together through nutrient cycles and energy flows. Energy is incorporated into plant tissue. By feeding on plants and on one-another, animals play an important role in the movement of matter and energy through the system, they influence the quantity of plant and microbial biomass present. By breaking down dead organic matter, decomposers release carbon back to the atmosphere and facilitate nutrient cycling by converting nutrients stored in dead biomass back to a form that can be used by plants and other microbes. Ecosystems are controlled by internal factors. External factors such as climate, the parent material which forms the soil and topography, control the overall structure of an ecosystem, but are not themselves influenced by the ecosystem. Ecosystems are dynamic entities—they are subject to periodic disturbances and are in the process of recovering from some past disturbance.
Ecosystems in similar environments that are located in different parts of the world can end up doing things differently because they have different pools of species present. Internal factors not only control ecosystem processes but are controlled by them and are subject to feedback loops. Resource inputs are controlled by external processes like climate and parent material. Resource availability within the ecosystem is controlled by internal factors like decomposition, root competition or shading. Although humans operate within ecosystems, their cumulative effects are large enough to influence external factors like climate. Biodiversity affects ecosystem functioning, as do the processes of disturbance and succession. Ecosystems provide a variety of services upon which people depend; the term ecosystem was first used in 1935 in a publication by British ecologist Arthur Tansley. Tansley devised the concept to draw attention to the importance of transfers of materials between organisms and their environment.
He refined the term, describing it as "The whole system... including not only the organism-complex, but the whole complex of physical factors forming what we call the environment". Tansley regarded ecosystems not as natural units, but as "mental isolates". Tansley defined the spatial extent of ecosystems using the term ecotope. G. Evelyn Hutchinson, a limnologist, a contemporary of Tansley's, combined Charles Elton's ideas about trophic ecology with those of Russian geochemist Vladimir Vernadsky; as a result, he suggested. This would, in turn, limit the abundance of animals. Raymond Lindeman took these ideas further to suggest that the flow of energy through a lake was the primary driver of the ecosystem. Hutchinson's students, brothers Howard T. Odum and Eugene P. Odum, further developed a "systems approach" to the study of ecosystems; this allowed them to study the flow of material through ecological systems. Ecosystems are controlled both by internal factors. External factors called state factors, control the overall structure of an ecosystem and the way things work within it, but are not themselves influenced by the ecosystem.
The most important of these is climate. Climate determines the biome. Rainfall patterns and seasonal temperatures influence photosynthesis and thereby determine the amount of water and energy available to the ecosystem. Parent material determines the nature of the soil in an ecosystem, influences the supply of mineral nutrients. Topography controls ecosystem processes by affecting things like microclimate, soil development and the movement of water through a system. For example, ecosystems can be quite different if situated in a small depression on the landscape, versus one present on an adjacent steep hillside. Other external factors that play an important role in ecosystem functioning include time and potential biota; the set of organisms that can be present in an area can significantly affect ecosystems. Ecosystems in similar environments that are located in different parts of the world can end up doing things differently because they have different pools of species present; the introduction of non-native species can cause substantial shifts in ecosystem function.
Unlike external factors, internal factors in ecosystems not only control ecosystem processes but are controlled by them. They are subject to feedback loops. While the resource inputs are controlled by external processes like climate and parent material, the availability of these resources within the ecosystem is controlled by internal factors like decomposition, root competition or shading. Other factors like disturbance, succession or the types of species present are internal factors. Primary production is the production of organic matter from inorganic carbon sources; this occurs through photosynthesis. The energy incorporated through this process supports life on earth, while the carbon makes up much of the organic matter in living and dead biomass, soil carbon and fossil fuels, it drives the carbon cycle, which influences global climate via the greenhouse effect. Through the process of photosynthesis, plants capture energy from light and use it to combine carbon dioxide and water to produce carbohydrates and oxygen.
The photosynthesis carried out by all the plants in an ecosystem is called the gross primary production. About half of the GPP is consumed in plant respiration; the remainder, that portion of GPP, not used up by respirati
Squirrel
Squirrels are members of the family Sciuridae, a family that includes small or medium-size rodents. The squirrel family includes tree squirrels, ground squirrels, marmots, flying squirrels, prairie dogs amongst other rodents. Squirrels are indigenous to the Americas and Africa, were introduced by humans to Australia; the earliest known squirrels date from the Eocene period and are most related to the mountain beaver and to the dormouse among other living rodent families. The word "squirrel", first attested in 1327, comes from the Anglo-Norman esquirel, from the Old French escurel, the reflex of a Latin word sciurus; this Latin word was borrowed from the Ancient Greek word σκίουρος, which means shadow-tailed, referring to the bushy appendage possessed by many of its members. The native Old English word for the squirrel, ācweorna, survived only into Middle English before being replaced; the Old English word is of Common Germanic origin, cognates of which are still used in other Germanic languages, including the German Eichhörnchen, the Norwegian ikorn/ekorn, the Dutch eekhoorn, the Swedish ekorre and the Danish egern.
Squirrels are small animals, ranging in size from the African pygmy squirrel at 7–10 cm in length and just 10 g in weight, to the Laotian giant flying squirrel at 1.08 m in length and the Alpine marmot, which weighs from 5 to 8 kg. Squirrels have slender bodies with bushy tails and large eyes. In general, their fur is silky, though much thicker in some species than others; the coat color of squirrels is variable between—and even within—species. In most squirrel species, the hind limbs are longer than the fore limbs, while all species have either four or five toes on each paw; the paws, which include an poorly developed thumb, have soft pads on the undersides and versatile, sturdy claws for grasping and climbing. Tree squirrels, unlike most mammals, can descend a tree head-first, they do so by rotating their ankles 180 degrees, enabling the hind paws to point backward and thus grip the tree bark from the opposite direction. Squirrels live in every habitat, from tropical rainforest to semiarid desert, avoiding only the high polar regions and the driest of deserts.
They are predominantly herbivorous, subsisting on seeds and nuts, but many will eat insects and small vertebrates. As their large eyes indicate, squirrels have an excellent sense of vision, important for the tree-dwelling species. Many have a good sense of touch, with vibrissae on their limbs as well as their heads; the teeth of sciurids follow the typical rodent pattern, with large incisors that grow throughout life, cheek teeth that are set back behind a wide gap, or diastema. The typical dental formula for sciurids is 1.0.1.31.0.1.3. Many juvenile squirrels die in the first year of life. Adult squirrels can have a lifespan of 5 to 10 years in the wild; some can survive 10 to 20 years in captivity. Premature death may be caused when a nest falls from the tree, in which case the mother may abandon her young if their body temperature is not correct. Many such baby squirrels have been rescued and fostered by a professional wildlife rehabilitator until they could be safely returned to the wild, although the density of squirrel populations in many places and the constant care required by premature squirrels means that few rehabilitators are willing to spend their time doing this and such animals are euthanized instead.
Squirrels mate either once or twice a year and, following a gestation period of three to six weeks, give birth to a number of offspring that varies by species. The young are altricial, being born naked and blind. In most species of squirrel, the female alone looks after the young, which are weaned at six to ten weeks and become sexually mature by the end of their first year. In general, the ground-dwelling squirrel species are social living in well-developed colonies, while the tree-dwelling species are more solitary. Ground squirrels and tree squirrels are either diurnal or crepuscular, while the flying squirrels tend to be nocturnal—except for lactating flying squirrels and their young, which have a period of diurnality during the summer; because squirrels cannot digest cellulose, they must rely on foods rich in protein and fats. In temperate regions, early spring is the hardest time of year for squirrels because the nuts they buried are beginning to sprout, while many of the usual food sources have not yet become available.
During these times, squirrels rely on the buds of trees. Squirrels, being herbivores, eat a wide variety of plants, as well as nuts, conifer cones, fruits and green vegetation; some squirrels, however consume meat when faced with hunger. Squirrels have been known to eat small birds, young snakes, smaller rodents, as well as bird eggs and insects. Indeed, some tropical squirrel species have shifted entirely to a diet of insects. Predatory behavior has been observed in various species of ground squirrels, in particular the thirteen-lined ground squirrel. For example, Bailey, a scientist in the 1920s, observed a thirteen-lined ground squirrel preying upon a young chicken. Wistrand reported seeing this same species eating a freshly killed snake. Whitaker examined the stomachs of 139 thirteen-lined ground squirrels and found bird flesh in four of the specimens and the remains of a short-tailed shrew in one.
Dispersal vector
A dispersal vector is an agent of biological dispersal that moves a dispersal unit, or organism, away from its birth population to another location or population in which the individual will reproduce. These dispersal units can range from pollen to seeds to fungi to entire organisms. There are two types of those that are active and those that are passive. Active dispersal involves organisms. In passive dispersal, the organisms have evolved dispersal units, or propagules, that use the kinetic energy of the environment for movement. In plants, some dispersal units have tissue that are called diaspores; some dispersal is self-driven, such as using gravity, does not rely on external vectors. Other types of dispersal are due to external vectors, which can be biotic vectors, such as animals, or abiotic vectors, such as the wind or water. In many cases, organisms will be dispersed by more than one vector before reaching its final destination, it is a combination of two or more modes of dispersal that act together to maximize dispersal distance, such as wind blowing a seed into a nearby river, that will carry it farther down stream.
Autochory is the dispersal of diaspores, which are dispersal units consisting of seeds or spores, using only the energy provided by the diaspore or the parent plant. The plant of origin is the dispersal vector itself, instead of an external vector. There are four main types of autochory that act on diaspores: ballochory, or violent ejection by the parent organism. In some cases, ballochory can be more effective when utilizing a secondary dispersal vector: ejecting the seeds in order for them to use wind or water for longer distance dispersal. Animal-mediated dispersal is called zoochory. Zoochory can be further described by. Animals are an important dispersal vector because they provide the ability to transfer dispersal units longer distances than their parent organism can; the main groups include dispersal by birds, dispersal by ants, dispersal by mammals, dispersal by amphibians or reptiles, dispersal by insects, such as bees. Animals are a large contributor to pollination via zoophily. Flowering plants overwhelmingly are pollinated by animals, while invertebrates are involved in the majority of that pollination and mammals play a role.
Birds contribute to seed dispersal in several ways. Birds cache, or store, the seeds of trees and shrubs for consumption. Long-distance dispersal, rare for a parent plant to achieve alone, could be mediated by migratory movements of birds. Long-distance dispersal operates over spatial areas that span thousands of kilometers, which allow it to promote rapid range shifts and determine species distributions. In seed dispersal, ingestion of seeds that are capable of resisting digestive juices allows the seeds to be scattered in feces and dispersed far from the parent organism. For these seeds, gut passage enhances germination ability when the seeds are ingested by birds and mammals. Ingestion of herbivores by carnivorous animals may help disperse seeds by preying on primary seed dispersers such as herbivores or omnivores; when a bird is eaten by a cat or another carnivore, that animal will inadvertently consume the seeds that the prey species consumed. These seeds may be deposited in a process called diplochory, where a seed is moved by more than one dispersal vector, important for seed dispersal outcomes as carnivores range and enhance the genetic connectivity of dispersed populations.
Birds act as dispersal vectors for non-seed dispersal units as well. Hummingbirds spread pollen on their beaks, fungal spores may stick to the bottom of birds’ feet. Water birds may help to disperse aquatic invertebrates branchiopods and bryozoans; this includes all of the dispersal caused by ants, including seed dispersal and the dispersal of leaf matter from trees. To birds, dispersal by mammals allows for long distance dispersal via carnivores; the act of carnivores eating primary dispersal vectors can lead to long distance dispersal and connection between different populations of the same species because of large predator ranges in comparison to smaller herbivore ranges. Mammals have been shown to act as dispersal vectors for seeds and parasites. Just as in ornithocory, ingestion by herbivores acts as a dispersal vector for seeds, gut passage increases the rate of germination. Marsupials, rodents and some species in the suborder Feliformia have all been identified as pollinators. Non-flying mammals have been identified as acting as pollinators in Australia, Africa and Central America.
Some plants may have traits that coevolved to utilize mammals as dispersal vectors, such as being pungent in odor, nocturnal nectar production, robust flowers that can handle rough feeders. The pollen of some plants can be found stuck to the fur of mammals as well as accidentally ingested when nectar is consumed. Mammals contribute to fern spore dispersal by carrying spores on their fur. Small mammals acting as dispersal vectors may have advantages for the dispersing organism comp
.jpg)
.jpg)
