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Name ____________________________________ Spring Field Trip Ecology is the study of the interaction of organisms with their environment. The organism interacts with both biotic (living) and abiotic (non-living) components of its environment. We are interested in how these components help explain the diversity of living organisms and the distribution of any particular organism in the environment through time. During the term you have made observations of plants out of their natural environment; today you will observe some of our native plants in their normal surroundings. Your class meeting will take place at the Arboretum on the ECSU campus. I. ECOLOGICAL OBSERVATIONS On your field trip you should take notes on your own observations as well as those of your instructor and classmates. You will observe POPULATIONS (members of the same species within an area) that comprise a COMMUNITY (the different populations that interact and occupy an area). A community interacting with the physical factors of the environment is known as an ECOSYSTEM. A. TERRESTRIAL ECOSYSTEMS. You should be able to find ecosystems that mimic natural woods, prairie, and old fields. 1. Abiotic Factors. At each ecosystem, note any slope, exposure to wind, light intensity and overall temperature. Note obvious soil texture and composition as well as potential for drainage. Determine the relative amount of litter above the soil. 2. Biotic Factors. Observe the species that dominate the ecosystem in terms of biomass. Is there any stratification (layering)? If so, what factors are different between the layers? Do these help explain why certain species are dominant at each layer? Look for the plants you have observed this term; examples of each major group should be evident today. Identify the major angiosperms by using the key on subsequent pages. Go out of your way to observe the animals that interact with the plants; look for herbivores, parasites, pollinators, dispersers, and predators. If you cannot see animals, you may be able to observe the results of their presence: droppings, leaf/bark/fruit wall damage, fruit set. In what ways have the abiotic factors determined what plants are present and the positions they occupy within this ecosystem? In what ways have the plants of this ecosystem determined the abundance and success of animal species? 3. Organism interactions. Make observations on how the following categories are exemplified in each ecosystem: a. Food Chains--production, herbivory, predation, decomposition b. Symbioses--mutualism, commensalism, parasitism c. Competition--intraspecific, interspecific d. Structural--support, concealment, protection How many producer individuals are there relative to herbivores and carnivores? How does energy flow in this ecosystem? How do species protect themselves from those "higher" on the food chain? Take time out to observe the often overlooked decomposers; how important are they to the mineral nutrition of this ecosystem? Document © Ross E. Koning 1994. Permission granted for non-commercial instruction. Koning, Ross E. 1994. Spring Field Trip. Plant Information Website. http://plantphys.info/organismal/labdoc/springfieldtrip.doc It may be difficult to observe competition, particularly since the superior competitors have already succeeded, but you may note how successful the younger members of these species are faring with respect to established individuals. What resources may be limiting in this ecosystem? How are the successful species well-adapted to monopolize these resources or more efficiently use them? Are any of the plants spatially or temporally separating their efforts with respect to the annual efforts of other plants? 4. Change. Look for evidence of succession. Some types of change are brought about by the natural process of making new habitats; conversion of exposed bedrock to niches for plants and buildup of a soil. What are the pioneer species in this ecosystem? What is the climax community? How does each successive group of plants alter the environment to lead to the next level of succession? This would be an example of primary succession. Secondary succession occurs when a community is destroyed and a second round of succession is allowed to proceed. An old field going back to forest is an example of secondary succession. What are the species involved with this type of succession? B. Aquatic ecosystems. You will also observe a stream and a pond. Ask some of the same questions outlined above. Again look for species you already recognize, ask your instructor to help identify others. How do concepts such as food chains, symbioses, competition, and succession apply to an aquatic ecosystem? What are the limiting resources? What abiotic factors seem most important to survival? II. NON-FLOWERING PLANTS OF NOTE A. Algae. Most individual algae cannot be observed without the aid of a microscope, however some algae that are filamentous, colonial, or parenchymatous can be seen en masse. In the creek you might notice Ulothrix growing on many of the rock surfaces with wispy tufts of filaments wafting downstream. Depending on weather, the filaments are likely disintegrating as motile cells (zoospores and/or gametes) are released in early spring. If tree bark and/or rock surfaces in the arboretum appear green-tinted, there may be a thin film of algae coating these surfaces. The only way to identify these would be to return samples to the laboratory for microscopic analysis. B. Fungi. Depending on weather, you may see a range of fungi or none at all. Mycelium is found in the ground or under bark; if you pull back some of the leaf litter you might find the thread-like rhizomorphs of fungal mycelium. You might observe jelly fungi and bracket (shelf) fungi on dead logs or branches. You might see cherry blight. In some years we find coral fungi, puffballs, and mushrooms of various sorts. One of the most interesting is an epiphytic rust...the cedar/apple rust on juniper trees...it resembles a pink sea urchin! Obviously planting junipers near apple trees is not adviseable as they are the alternate hosts for this fungus. Here you see this kind of planting at the edge of the arboretum. C. Bryophytes. Mosses abound on creek banks, wetland soils, and tree-trunk bases. Some will show the green gametophytes only, but some will have last year's and this year's sporophytes attached. Polytrichum sporophytes for this year will have a greenish-red seta and an orange-pink calyptra. Polytrichum lives in drier upland sites. Other species, such as Mnium are more likely found on wet sites. Do mosses live only on the north side of Page 2 tree trunks; you might look at trees out in the open and trees in the deep woods before you give a good answer. Liverwort colonies occur on the banks of the creek, but are relatively rare. I have collected Conocephalum and Pallavicinnia there. Sphagnum moss is found in very wet soils in the floodplain. If you find a good hummock, try squeezing a small portion of the gametophytes to see what happens. D. Ferns and Allies. At this time of year, deciduous ferns are rapidly developing from perennial rhizomes. Fiddleheads should be easy to find, but the species of fern they represent is impossible to tell for most taxa. When fronds become reproductive it may be easier to determine which is which. Evergreen ferns of Connecticut include Polystichum acrostichoides (Christmas fern). You will also find last year's fertile fronds of Onoclea (sensitive fern) and Botrychium (grape fern). The fern allies are abundant. You should find Lycopodium lucidulum, L. obscurum, L. complanatum and Equisetum arvensis. Club moss sporophylls and strobili from last fall should still be visible. Horsetail strobili are likely over-the-hill, but vegetative shoots should be quite obvious. Selaginella would be found only in wet lawns...not in our arboretum (as far as I have looked). E. Gymnosperms. Our woods naturally include Juniperis virginiana (Juniper), Pinus strobus (White Pine), and Tsuga canadensis (Canadian Hemlock). You might also find Taxus cuspidata (Yew) as an escapee from cultivation. You might try to locate megasporangiate and microsporangiate cones. Juniper is a secondary successional species; how can you tell from its distribution? You will see arbor vitae planted at the margins of the arboretum parking lot. These are great landscaping gymnosperms. Depending on weather you might find pollination droplets on some of the naked ovules...especially "female" yews. III. ANGIOSPERM IDENTIFICATION The structure of the flower is commonly used in identifying an unknown flowering plant. A key, constructed to separate groups of species or individual species on the basis of contrasting characteristics, is usually followed in trying to determine the identity of a plant. For a part of the country, such as the northeastern United States, where a great many species are involved, the keys are lengthy and include many detailed aspects of the flower, fruit, and vegetative plant. Considerable experience and familiarity with complex terminology is needed before such a key can be followed with any ease. A short and simplified key is included here to allow you to identify approximately 20 different flowers, and to gain a little experience in the use of a key. You should be able to find at least some of the plants represented in the key. Roman numerals indicate the plant family while arabic numerals identify the genus and common name of each plant in the appended list. Page 3 A DICHOTOMOUS KEY FOR 20 SPRING ANGIOSPERMS A Perianth parts in 3's; leaves mostly parallel-veined ................................. MONOCOT B B Perianth none; flowers imperfect; spathe and spadix present ................................ C C Leaf divided into three lobes ........................................................................... I-1 CC Leaf unlobed and ovate ................................................................................... I-2 BB Perianth present; flowers perfect; no spathe or spadix present ............................... D D Ovary superior ..................................................................................................... E E Leaves in basal rosette, leaf spotted, flowers on long scape..................... II-3 EE Leaves held on elongate stem...................................................................... F F Flowers or flower clusters terminal ....................................................... G G Flowers solitary or small group ...................................................... II-4 GG Flowers numerous in large raceme .............................................. II-5 FF Flowers produced laterally along the stem; leaves along stem ........... II-6 DD Ovary inferior .............................................................................................. III-7 AA Perianth parts usually in 4's or 5's; leaves mostly net-veined..........................DICOT G G Ovary completely superior ...................................................................................... H H Perianth present .................................................................................................. I I Flowers radially symmetric............................................................................ J J Gynoecium of 4-15 separate pistils .................................................. K K Leaves whorled, 3-5 lobes................................................... IV-8 KK Leaves alternate, numerous lobes ........................................ IV-9 JJ Gynoecium of 1 simple or compound pistil................................ V-10 II Flowers slightly to highly zygomorphic ........................................................ L L Woody; stamens 5-10 ..................................................................... VI-11 LL Herbaceous; stamens 5-8 ...................................................................... M M Stamens 5; petals with nectar spur ................................................ N N Leaf blades no lobed ........................................................ VII-12 NN Leaf blades deeply lobed .................................................. VII-13 MM Stamens 8; petals lacking nectar spur ..................................VIII-14 HH Perianth absent; flowers subtended by petal-like bracts ........................... IX-15 GG Ovary inferior or partly so ...................................................................................... O O Flowers radially symmetric, not in flattened head ...................................... P P Ovary only partly inferior; styles 2 or more .................................... X-16 PP Ovary completely inferior; style 1 ......................................................... Q Q Petals 4 .................................................................................... XI-17 QQ Petals 5 or more .............................................................................. R R Stamens 6 ......................................................................... XII-18 RR Stamens 5.........................................................................XIII-19 OO Flowers bilaterally symmetric; in flattened head ............................. XIV-20 Page 4 FLOWERS INCLUDED IN THE SPRING KEY FAMILY TAXON COMMON NAMES I Araceae 1 Arisaema 2 Symplocarpus Jack in the pulpit skunk cabbage II Liliaceae 3 Erythronium 4 Trillium 5 Smilacena racemosa 6 Polygonatum biflorum trout lily trillium false Solomon's seal Solomon's seal III Orchidaceae 7 Cypripedium acaule lady slipper orchid IV Ranunculaceae 8 Anemone quinquefolia 9 Ranunculus wood anemone buttercup V Brassicaceae 10 Barbarea winter cress VI Fabaceae 11 Cercis redbud VII Violaceae 12 Viola papilionacea 13 Viola pedata common blue violet bird's foot violet VIII Polygalaceae 14 Polygala paucifolia gaywings IX Euphorbiaceae 15 Euphorbia cyparissias cypress spurge X Rosaceaeceae 16 Potentilla potentilla XI Rubiaceae 17 Houstonia bluets XII Berberidaceae 18 Berberis thunbergii Japanese barberry XIII Caprifoliaceae 19 Viburnum viburnum XIV Asteraceae 20 Taraxacum dandelion Special note: Isotria verticillata is an exceedingly rare orchid found in our arboretum. It is perhaps 20 cm tall with a 5-8 cm flower above a single whorl of leaves. The flower is greenish with brown and faint purple markings...kind of "spidery" in appearance. If you find one, for goodness sake don't pick it, they flower about once per decade! Page 5