MATERI KULIAH DINAMIKA LINGKUNGAN TERNAK

Apa yang dimaksudkan dengan lingkungan ternak?

Perhatian pertama harus diberikan pada kata lingkungan yang dalam hal ini harus memperhatikan beberapa hal sebagai berikut, yaitu:

1. asal mula ilmu lingkungan adalah ekologi, yaitu ilmu yang mempelajari hubungan timbal balik antara organisme dan lingkungannya di mana interaksi tersebut akan menentukan produktivitas, ukuran populasi dan persebaran organisme dan sebaliknya akan menentukan rona lingkungan.
2 dalam kajian ilmu lingkungan, suatu organisme selalu dipelajari dalam konteks unit populasi yang harus dimengerti dalam beberapa sudut pandang:

• Populasi adalah kumpulan individu suatu spesies organisme yang hidup secara bersama-sama dalam suatu ruang dan waku tertentu. Pertanyaan: berapa banyak individu untuk membentuk suatu populasi dan berapa luas ruang yang dapat dihuni oleh sebuah populasi.
• Karena pertanyaan tentang banyak individu seperti di atas maka batasan populasi didasarkan atas pengaruh suatu individu terhadap individu lain dalam populasi. Oleh karena itu:
• populasi adalah suatu sistem yang dinamis dari segala individu yang selalu melakukan hubungan
• Populasi adalah kumpulan individu sebuah spesies yang mempunyai potensi untuk berinteraksi satu dengan yang lainnya dan khusus antara individu jantan dan betina harus memiliki potensi untuk berbiak silang antar individu.

• Dalam konteks pertanyaan tentang luas ruang maka populasi individu harus dikaitkan dengan rasio antara jumlah individu dan luas ruang, yaitu kepadatan (density) individu. Jika jumlah individu > ukuran ruang maka akan timbul efek negatif berupa persaingan (kompetisi) dengan 2 akibat, yaitu:

· Jika terjadi dalam waktu yang singkat maka akan menimbulkan efek ekologi dengan kemungkinan gejala: (1) meningkatnya mortalitas dan tertekannya kelahiran, daya tahan hidup dan pertumbuhan populasi; dan (2) peningkatan emigrasi.

· Jika terjadi dalam waktu yang panjang maka akan menimbulkan efek evolusi, yaitu tersingkirnya sama sekali individu yang kalah dalam persaingan sehingga struktur populasi dikuasai oleh individu kuat (survival of the fittest).

• Terkait dengan isu persaingan dan kepadatan populasi maka terdapat 2 faktor lingkungan yang amat menentukan daya biak populasi, yaitu:

· Faktor bergantung kepadatan (density dependent factor), misalnya kekurangan ruang dan bahan makanan karena populasi terlampau padat.

· Faktor tidak tergantung kepadatan (density independent factor) misalnya cold stress, heat stress, angin ribut, hama, predator dan lain sebagainya yang bisa terjadi kapan saja (hazards).

• Untuk dapat memahami populasi maka harus diperhatikan beberapa ciri atau sifat-sifat kelompok populasi sebagai berikut:

1. laju perkembangan populasi à tugas

2. natalitas (kelahiran) à tugas

3. mortalitas à tugas

4. kerapatan (sudah dijelaskan di atas)

5. struktur dan sebaran umur

6. dispersi dan bentuk pertumbuhan serta kaitannya dengan daya dukung

7. tipe interaksi antar spesies

(1-3 adalah sifat populasi terkait sifat genetis individu dalam populasi – seleksi r; sedangkan 4 – 7 adalah sifat populasi terkait numerikal dan struktur populasi).

3. Karena sifat-sifat populasi di atas maka kajian dinamika lingkungan ternak harus juga melibatkan konsep komunitas karena populasi dalam ruang pasti terdiri atas lebih dari 1 populasi.

• Kepadatan populasi akan membentuk keanekaragaman, yaitu keanekaragaman di dalam spesies populasi-populasi (misalnya jenis kelamin dan jenis interaksi) dan keanekaragaman dalam hal penyebaran.
• Sifat terpenting dari komunitas dalam kaitannya dengan populasi adalah komunitas memiliki tingkat perkembangan, yaitu lahir, meningkat dan menua. Proses ini yang disebut sebagai suksesi menuju masyarakat komunitas yang mapan (puncak atau klimaks). Pada tahap puncak, komunitas memerlukan gangguan untuk menjaga stabilitasnya. Contoh adalah suksesi klimaks Krakatau antara 1886 – 1986.

4. Akhirnya, oragnisasi organisme yang tertinggi adalah ekosistem, yaitu komunitas + komponen abiotik, yaitu klimatik dan edafik.

Proses dasar dalam ekosistem adalah (1) aliran materi dan (2) siklus bahan.

• Untuk mempermudah pendugaan produktivitas ekosistem maka pola jaringan makanan disederhanakan menjadi piramida ekologi (struktur makanan)

Jadi, produktivitas pada tingkat makanan bagian atas dapat ditingkatkan jika produktivitas pada bagian paling bawah ditingkatkan. Hal inilah yang disebut sebagai efisiensi produktivitas.

• Produksi primer bersih atau P₁ = FS (hasil kotor atau FS – Respirasi atau R₁)
• Produksi sekunder bersih atau P₂ = P₁ – (R₁ + kerja + limbah melalui feces dan urine)
• Produksi tersier bersih atau P₃ = P₂ – (R₂ + kerja + limbah melalui feces dan urine)
  

Suatu perhampiran umum adalah: faktor 10%, maksudnya: jika lahan dan air pada suatu lokasi memproduksikan 1000 kg bobot kering rumput/tahunà akan menghasilkan 100 kg bobot kering herbivora/kapita/tahun à akan menghasilkan 10 kg bobot kering karnivora/kapita/tahun (Ewusie, 1992). Akan tetapi angka ini hanya merupakan perhampiran. Ada biasnya. Apa? (tugas pribadi)

Tanaman Makanan Ternak (Bahan III): Sumbu Tumbuhan dan Bagian-Bagiannya

Axis of Plants

• Leaf - Specialised for organism for photosynthesis
• Stem - Ascending axis of plant growth
• Flower - Reproductive organ of angiosperms
• Root - Underground organ of the plant
• Leaf Primordia - Young recently formed leaves
• Shoot apex - Terminal bud of a plant
• Apical Meristem - Mitotically dividing cells that are found either at the shoot or root
• Auxillary Bud - Contains the apical meristems of shoot branches
• Node - Location on the stem where leaves/branches emerge from
  Internode - The stem between two nodes
• Vascular Tissue - Internal transport system of a plant (xylem, Phloem)
• Lateral root - Grow via secondary meristems derived from mature regions of root
• Taproot - Major root axis - other roots develop from the tap root
• Root hairs - fine extensions from roots that act to increase the surface area that the plant is in contact with
• Root Apex - The terminal area of the root that contains the meristemic tissue
• Root Cap - Cells located at the growing tip of the root that help to protect the meristemic tissue

Grass Structure

Knowing the names of specific plant parts will provide a foundation for in-depth discussions of mechanisms which account for growth and recovery following defoliation. The diagram and definitions are divided into three categories: vegetative, floral (reproductive), and collar. During early growth, while a grass plant is vegetative, identification is difficult. When floral structures are visible, identification is easier. The collar region is helpful for identification and it contains a band of intercalary meristem which, when properly safe-guarded, will account for regrowth following mowing or grazing.

Vegetative Structures

Notice the following labeled items on the drawing:

• peduncle: upper most culm segment supporting the seed head.
• flag leaf: uppermost leaf of the culm, enclosing the seed head during the boot stage.
• culm node: solid region on the culm which gives rise to a leaf sheath. On certain grass species, lower culm nodes may bear adventitious buds capable of producing new tillers.
• culm: central axis of the mature grass shoot, comprised of nodes and internodes; each node bearing a leaf.
• leaf blade: part of the leaf above the sheath, also known as the lamina.
• leaf sheath: lower section of a grass, enclosing its associated culm internode.
• auricles: short, often claw-like appendages at the base of the leaf blade which tend to clasp the sheath at the culm internode. The various shapes can be useful for identifying certain grasses.
• ligule: a variously modified extension of the sheath lying at the base of the blade; often a vertical membrane, and in certain cases, mere bristles.
• crown: basal zone of the shoot, the origin of which was tissue at the base of the coleoptile during the seedling stage. The crown is essential for the perennial growth of the plant as this zone is comprised of over-wintering tissues (basal internodes, rhizomes, stolons, corms) which produce new shoots the following spring. Annual grasses do not develop a crown.
• stolon: a prostrate or creeping, above-ground stem, rooting at the nodes; a means of vegetative reproduction.
• rhizome: a prostrate subterranean stem, capable of rooting at the nodes and becoming erect at the apex; a means of vegetative reproduction.
• tiller: a daughter plant, a shoot capable of producing a new plant.
• meristem: the cells capable of growth

collar region: The collar region of the leaf is the most useful area for identifying vegetative-stage grasses. Later on, after seed head emergence, floral structures may provide a more obvious means of identification. The collar region consists of the leaf blade, the leaf sheath wrapping around the stem, auricles (if present), a ligule, and connective tissue called the collar. Each species is unique with respect to the presence, size, and shape of the auricles and ligules in this leaf zone. The collar (connective tissue) is a narrow band of intercalary meristem (tissue capable of growth) which accounts for blade growth. With immature blades, this meristem provides for further blade growth following defoliation. The collar region is also important in grass management. When properly safe-guarded, this band of intercalary meristem will account for contin ued blade growth following mowing or grazing of immature leaf blades.

Floral Structure

• inflorescence: flower head terminating the stem, consisting of a collection of flowers arranged on a common axis. There are three main grass inflorescence types: 1. panicle, 2. spik e, 3. raceme.
• rachis : central axis of seed head.

• spikelet: a flowering unit comprised of one or more florets enclosed by two glumes (bracts). When the spikelets are attached directly to the rachis the inflorescence is called a spike (wheat, rye, barley, ryegrass). When the spikelets are attached to the rachis with short pedicels, the inflorescence is termed as raceme. When the spikelets are attached by means of a branch the inflorescence is said to be a panicle.
• pedicel: in grasses, a short stem segment supporting a spikelet. Such spikelets are said to be pedicellate.
• glume(s): bracts which enclose the floret(s). A spikelet can be described as a "pair" of glumes with the enclosed floret(s). The outer (lower) glume is always the largest of the pair. In some species (Paniceae family) the uppermost glume is greatly reduced and is largely replaced by the lemma of a sterile floret contained within.
• floret: small flower; the reproductive unit of a grass spikelet consisting of a lemma and palea and the small flower they contain (see spikelet).
• rachilla: the segmented central axis of a spikelet is prominent in spikelets which bear two or more fertile florets. Each rachilla segment bears a floret, thus in threshed form, a single seed usually retains a rachilla segment or joint. The presence or absence of a rachilla segment provides a means of recognizing many seeds. Further, the shape and size of the segment is widely contrasted among species.
• lemma: the larger, outer, bract which, along with the palea, serves to contain the floret(s) held within. The lemma and palea provide a protective covering for the developing floret as well as for the seed after ripening.
• awn: a fibrous bristle (often called a beard) which is an extension of the midrib of the lemma. It may arise from the tip of the lemma or from the abaxial (outer) surface below the tip.
• beard: common term for awn.
• palea: the shorter, upper, bract which, along with the lemma, serves to contain the floret(s) held within (see lemma).
• stamens: the male organ of a flower supporting anthers which produce pollen.
• anther: the pollen bearing portion of a stamen, composed of one or two pollen sacs.
• pollen: the structures that result from the maturation of a microspore.
• pistil: the female organ of the flower comprised of the stigma, style, and ovary. The stigma receives pollen grain, which upon germination, produces a pollen tube which passes through the stigma into the ovary.

Tanaman Makanan Ternak (Bahan II): Fotosintesis

Fotosintesis

Fotosintesis adalah suatu proses biokimia yang dilakukan tumbuhan, alga, dan beberapa jenis bakteri untuk memproduksi energi terpakai (nutrisi) dengan memanfaatkan energi cahaya. Hampir semua makhluk hidup bergantung dari energi yang dihasilkan dalam fotosintesis. Akibatnya fotosintesis menjadi sangat penting bagi kehidupan di bumi. Fotosintesis juga berjasa menghasilkan sebagian besar oksigen yang terdapat di atmosfer bumi. Organisme yang menghasilkan energi melalui fotosintesis (photos berarti cahaya) disebut sebagai fototrof. Fotosintesis merupakan salah satu cara asimilasi karbon karena dalam fotosintesis karbon bebas dari CO2 diikat (difiksasi) menjadi gula sebagai molekul penyimpan energi. Cara lain yang ditempuh organisme untuk mengasimilasi karbon adalah melalui kemosintesis, yang dilakukan oleh sejumlah bakteri belerang.

Fotosintesis pada tumbuhan

Tumbuhan bersifat autotrof. Autotrof artinya dapat mensintesis makanan langsung. dari senyawa anorganik. Tumbuhan menggunakan karbon dioksida dan air untuk menghasilkan gula dan oksigen yang diperlukan sebagai makanannya. Energi untuk menjalankan proses ini berasal dari fotosintesis. Perhatikan persamaan reaksi yang menghasilkan glukosa berikut ini:

12H₂O + 6CO₂ + cahaya → C₆H₁₂O₆ (glukosa) + 6O₂ + 6H₂O

Glukosa dapat digunakan untuk membentuk senyawa organik lain seperti selulosa dan dapat pula digunakan sebagai bahan bakar. Proses ini berlangsung melalui respirasi seluler yang terjadi baik pada hewan maupun tumbuhan. Secara umum reaksi yang terjadi pada respirasi seluler berkebalikan dengan persamaan di atas. Pada respirasi, gula (glukosa) dan senyawa lain akan bereaksi dengan oksigen untuk menghasilkan karbon dioksida, air, dan energi kimia.

Tumbuhan menangkap cahaya menggunakan pigmen yang disebut klorofil. Pigmen inilah yang memberi warna hijau pada tumbuhan. Klorofil terdapat dalam organel yang disebut kloroplas. klorofil menyerap cahaya yang akan digunakan dalam fotosintesis. Meskipun seluruh bagian tubuh tumbuhan yang berwarna hijau mengandung kloroplas, namun sebagian besar energi dihasilkan di daun. Di dalam daun terdapat lapisan sel yang disebut mesofil yang mengandung setengah juta kloroplas setiap milimeter perseginya. Cahaya akan melewati lapisan epidermis tanpa warna dan yang transparan, menuju mesofil, tempat terjadinya sebagian besar proses fotosintesis. Permukaan daun biasanya dilapisi oleh kutikula dari lilin yang bersifat anti air untuk mencegah terjadinya penyerapan sinar matahari ataupun penguapan air yang berlebihan.

Proses fotosintesis

Lihat pula artikel proses fotosintesis untuk informasi lebih rinci Hingga sekarang fotosintesis masih terus dipelajari karena masih ada sejumlah tahap yang belum bisa dijelaskan, meskipun sudah sangat banyak yang diketahui tentang proses vital ini. Proses fotosintesis sangat kompleks karena melibatkan semua cabang ilmu pengetahuan alam utama, seperti fisika, kimia, maupun biologi sendiri.

Pada tumbuhan, organ utama tempat berlangsungnya fotosintesis adalah daun. Namun secara umum, semua sel yang memiliki kloroplas berpotensi untuk melangsungkan reaksi ini. Di organel inilah tempat berlangsungnya fotosintesis, tepatnya pada bagian stroma. Hasil fotosintesis (disebut fotosintat) biasanya dikirim ke jaringan-jaringan terdekat terlebih dahulu.

Pada dasarnya, rangkaian reaksi fotosintesis dapat dibagi menjadi dua bagian utama: reaksi terang (karena memerlukan cahaya) dan reaksi gelap (tidak memerlukan cahaya tetapi memerlukan karbon dioksida).

Reaksi terang

Reaksi terang adalah proses untuk menghasilkan ATP dan reduksi NADPH₂. Reaksi ini memerlukan molekul air. Proses diawali dengan penangkapan foton oleh pigmen sebagai antena. Pigmen klorofil menyerap lebih banyak cahaya terlihat pada warna biru (400-450 nanometer) dan merah (650-700 nanometer) dibandingkan hijau (500-600 nanometer). Cahaya hijau ini akan dipantulkan dan ditangkap oleh mata kita sehingga menimbulkan sensasi bahwa daun berwarna hijau. Fotosintesis akan menghasilkan lebih banyak energi pada gelombang cahaya dengan panjang tertentu. Hal ini karena panjang gelombang yang pendek menyimpan lebih banyak energi.

Di dalam daun, cahaya akan diserap oleh molekul klorofil untuk dikumpulkan pada pusat-pusat reaksi. Tumbuhan memiliki dua jenis pigmen yang berfungsi aktif sebagai pusat reaksi atau fotosistem yaitu fotosistem II dan fotosistem I. Fotosistem II terdiri dari molekul klorofil yang menyerap cahaya dengan panjang gelombang 680 nanometer, sedangkan fotosistem I 700 nanometer. Kedua fotosistem ini akan bekerja secara simultan dalam fotosintesis, seperti dua baterai dalam senter yang bekerja saling memperkuat.

Fotosintesis dimulai ketika cahaya mengionisasi molekul klorofil pada fotosistem II, membuatnya melepaskan elektron yang akan ditransfer sepanjang rantai transpor elektron. Energi dari elektron ini digunakan untuk fotofosforilasi yang menghasilkan ATP, satuan pertukaran energi dalam sel. Reaksi ini menyebabkan fotosistem II mengalami defisit atau kekurangan elektron yang harus segera diganti. Pada tumbuhan dan alga, kekurangan elektron ini dipenuhi oleh elektron dari hasil ionisasi air yang terjadi bersamaan dengan ionisasi klorofil. Hasil ionisasi air ini adalah elektron dan oksigen.

Oksigen dari proses fotosintesis hanya dihasilkan dari air, bukan dari karbon dioksida. Pendapat ini pertama kali diungkapkan oleh C.B. van Neil yang mempelajari bakteri fotosintetik pada tahun 1930-an. Bakteri fotosintetik, selain sianobakteri, menggunakan tidak menghasilkan oksigen karena menggunakan ionisasi sulfida atau hidrogen.

Pada saat yang sama dengan ionisasi fotosistem II, cahaya juga mengionisasi fotosistem I, melepaskan elektron yang ditransfer sepanjang rantai transpor elektron yang akhirnya mereduksi NADP menjadi NADPH.

Reaksi gelap

ATP dan NADPH yang dihasilkan dalam proses fotosintesis memicu berbagai proses biokimia. Pada tumbuhan proses biokimia yang terpicu adalah siklus Calvin yang mengikat karbon dioksida untuk membentuk ribulosa (dan kemudian menjadi gula seperti glukosa). Reaksi ini disebut reaksi gelap karena tidak bergantung pada ada tidaknya cahaya sehingga dapat terjadi meskipun dalam keadaan gelap (tanpa cahaya).

Faktor penentu laju fotosintesis

Berikut adalah beberapa faktor utama yang menentukan laju fotosintesis:

1. Intensitas cahaya
   Laju fotosintesis maksimum ketika banyak cahaya.
2. Konsentrasi karbon dioksida
   Semakin banyak karbon dioksida di udara, makin banyak jumlah bahan yang dapt digunakan tumbuhan untuk melangsungkan fotosintesis.
3. Suhu
   Enzim-enzim yang bekerja dalam proses fotosintesis hanya dapat bekerja pada suhu optimalnya. Umumnya laju fotosintensis meningkat seiring dengan meningkatnya suhu hingga batas toleransi enzim.
4. Kadar air
   Kekurangan air atau kekeringan menyebabkan stomata menutup, menghambat penyerapan karbon dioksida sehingga mengurangi laju fotosintesis.
5. Kadar fotosintat (hasil fotosintesis)
   Jika kadar fotosintat seperti karbohidrat berkurang, laju fotosintesis akan naik. Bila kadar fotosintat bertambah atau bahkan sampai jenuh, laju fotosintesis akan berkurang.
6. Tahap pertumbuhan
   Penelitian menunjukkan bahwa laju fotosintesis jauh lebih tinggi pada tumbuhan yang sedang berkecambah ketimbang tumbuhan dewasa. Hal ini mungkin dikarenakan tumbuhan berkecambah memerlukan lebih banyak energi dan makanan untuk tumbuh.

Bahan Kuliah Ilmu Tanaman Makanan Ternak: Fisiologi Tumbuhan (bahan I)

Plant physiology is a subdiscipline of botany concerned with the function, or physiology, of plants.^[1] Closely related fields include plant morphology (structure of plants), plant ecology (interactions with the environment), phytochemistry (biochemistry of plants), cell biology, and molecular biology.

Fundamental processes such as photosynthesis, respiration, plant nutrition, plant hormone functions, tropisms, nastic movements, photoperiodism, photomorphogenesis, circadian rhythms, environmental stress physiology, seed germination, dormancy and stomata function and transpiration, both part of plant water relations, are studied by plant physiologists.

Scope

The field of plant physiology includes the study of all the internal activities of plants—those chemical and physical processes associated with life as they occur in plants. This includes study at many levels of scale of size and time. At the smallest scale are molecular interactions of photosynthesis and internal diffusion of water, minerals, and nutrients. At the largest scale are the processes of plant development, seasonality, dormancy, and reproductive control. Major subdisciplines of plant physiology include phytochemistry (the study of the biochemistry of plants) and phytopathology (the study of disease in plants). The scope of plant physiology as a discipline may be divided into several major areas of research.

First, the study of phytochemistry (plant chemistry) is included within the domain of plant physiology. In order to function and survive, plants produce a wide array of chemical compounds not found in other organisms. Photosynthesis requires a large array of pigments, enzymes, and other compounds to function. Because they cannot move, plants must also defend themselves chemically from herbivores, pathogens and competition from other plants. They do this by producing toxins and foul-tasting or smelling chemicals. Other compounds defend plants against disease, permit survival during drought, and prepare plants for dormancy. While other compounds are used to attract pollinators or herbivores to spread ripe seeds.

Secondly, plant physiology includes the study of biological and chemical processes of individual plant cells. Plant cells have a number of features that distinguish them from cells of animals, and which lead to major differences in the way that plant life behaves and responds differently from animal life. For example, plant cells have a cell wall which restricts the shape of plant cells and thereby limits the flexibility and mobility of plants. Plant cells also contain chlorophyll, a chemical compound that interacts with light in a way that enables plants to manufacture their own nutrients rather than consuming other living things as animals do.

Thirdly, plant physiology deals with interactions between cells, tissues, and organs within a plant. Different cells and tissues are physically and chemically specialized to perform different functions. Roots and rhizoids function to anchor the plant and acquire minerals in the soil. Leaves function to catch light in order to manufacture nutrients. For both of these organs to remain living, the minerals acquired by the roots must be transported to the leaves and the nutrients manufactured in the leaves must be transported to the roots. Plants have developed a number of means by which this transport may occur, such as vascular tissue, and the functioning of the various modes of transport is studied by plant physiologists.

Fourthly, plant physiologists study the ways that plants control or regulate internal functions. Like animals, plants produce chemicals called hormones which are produced in one part of the plant to signal cells in another part of the plant to respond. Many flowering plants bloom at the appropriate time because of light-sensitive compounds that respond to the length of the night, a phenomenon known as photoperiodism. The ripening of fruit and loss of leaves in the winter are controlled in part by the production of the gas ethylene by the plant.

Finally, plant physiology includes the study of how plants respond to conditions and variation in the environment, a field known as environmental physiology. Stress from water loss, changes in air chemistry, or crowding by other plants can lead to changes in the way a plant functions. These changes may be affected by genetic, chemical, and physical factors.

Early history

Sir Francis Bacon published one of the first plant physiology experiments in 1627 in the book, Sylva Sylvarum. Bacon grew several terrestrial plants, including a rose, in water and concluded that soil was only needed to keep the plant upright. Jan Baptist van Helmont published what is considered the first quantitative experiment in plant physiology in 1648. He grew a willow tree for five years in a pot containing 200 pounds of oven-dry soil. The soil lost just two ounces of dry weight and van Helmont concluded that plants get all their weight from water, not soil. In 1699, John Woodward published experiments on growth of spearmint in different sources of water. He found that plants grew much better in water with soil added than in distilled water.

Stephen Hales is considered the Father of Plant Physiology for the many experiments in the 1727 book^[8]; though Julius von Sachs unified the pieces of plant physiology and put them together as a discipline. His Lehrbuch der Botanik was the plant physiology bible of its time.^[9]

Researchers discovered in the 1800s that plants absorb essential mineral nutrients as inorganic ions in water. In natural conditions, soil acts as a mineral nutrient reservoir but the soil itself is not essential to plant growth. When the mineral nutrients in the soil are dissolved in water, plant roots absorb nutrients readily, soil is no longer required for the plant to thrive. This observation is the basis for hydroponics, the growing of plants in a water solution rather than soil, which has become a standard technique in biological research, teaching lab exercises, crop production and as a hobby.

Bahan Kuliah Pengelolaan Kawasan Konservasi

Conservation biology

Conservation biology, or conservation ecology, is the science of analyzing and protecting Earth's biological diversity. Conservation biology is an interdisciplinary subject drawing on biological, physical and social sciences, economics, and the practice of natural-resource management. The rapid decline of biological systems around the world means that conservation biology is often referred to as a "Discipline with a deadline"^[1]. Conservation ecology addresses population dynamics issues associated with the small population sizes of rare species (e.g., minimum viable populations). The term "conservation biology" refers to the Conservation biology is the scientific study of the phenomena that affect the maintenance, loss, and restoration of biological diversity and the application of science to the conservation of genes, populations, species, and ecosystems. For the history of biodiversity conservation and volunteer activity, see conservation movement.

In the 19th century actions in the United Kingdom, the United States and certain other western countries emphasized the protection of habitat areas pursuant to visions of such people as John Muir and Theodore Roosevelt. Not until the mid 20th century did efforts arise to target individual species for conservation, notably efforts in big cat conservation in South America led by the New York Zoological Society.^[2] By the 1970s, led primarily by work in the United States under the Endangered Species Act^[3] along with Biodiversity Action Plans developed in Australia, Sweden, the United Kingdom, hundreds of specific species protection plans ensued. The Society for Conservation Biology is a global community of conservation professionals dedicated to advancing the science and practice of conserving Earth's biological diversity.

Threats to biological diversity

Presently the Earth is undergoing the Holocene Mass Extinction, an era of unprecedented number of species extinctions.^[4] Human influence over the Earth's ecosystems has been so extensive within the last 10,000 years, that scientists have difficulty estimating the total number of species lost in this era;^[5] that is to say the rates of deforestation, reef destruction, wetlands filling and other human acts are proceeding much faster than human assessment of the Earth's species. The matter of ongoing species loss is made more complex by the fact that most of the Earth's species have not been described or evaluated for endangerment. The IUCN has found that 23 percent of vertebrates, 53 percent of invertebrates and 70 percent of plants that have been evaluated are designated as endangered or threatened.^[6] (The IUCN does not disaggregate endangered from critically endangered or threatened for the purpose of these statistics.)

Historically the main threat to biodiversity has been a set of threats generated from the overpopulation of humans: mass agriculture, deforestation, overgrazing, slash-and-burn, urban development, pesticide use.^[5] Worldwide, the effects of global warming add a potentially catastrophic threat to global biological diversity; a 2004 study by Chris Thomas, Lee Hannah, et al. estimated that 15 to 37 percent of all species would become extinct by 2050.^[7]

Importance of biological diversity

See also: Benefits of biodiversity

Biologist Bruce Walsh of the University of Arizona states three reasons for scientific interest in the preservation of species; genetic or medical resources,^[8][9] ecosystem stability, and ethics.^[10], and today the scientific community "stress[es] the importance" of maintaining biodiversity^[11].

Biodiversity provides many ecosystem services that are often not readily visible. It plays an essential part in regulating the chemistry of our atmosphere, pollinating crops and generating water supply. Biodiversity is directly involved in recycling nutrients and providing fertile soils. Experiments with controlled environments have shown that humans cannot easily build ecosystems to support human needs; for example insect pollination cannot be mimicked by man-made construction. The total value of ecosystem services may amount to trillions of dollars in ecosystem services per annum to mankind.^{[12][13][14][15]} For example, one segment of North American forests has been assigned an annual value of 250 billion dollars;^[16] as another example, honey-bee pollination, a small segment of ecosystem services, is estimated to provide between 10 and 18 billion dollars of value per annum.^[17] The value of ecosystem services on one New Zealand island has been imputed to be as great as the GDP of that region.^[18]

History

Conservation biologists trace the ethics that guide their work back to early spiritual philosophies, including the Tao, Shinto, Hindu, Islamic and Buddhist traditions.^[19] In the West, origins of concern for the destruction of the natural environment by man can be traced to Plato;^{[20][original research?]} however, modern roots of conservation biology can be found in the late 18th century Enlightenment period particularly in England and Scotland.^[21][22] A number of thinkers, among them notably Lord Monboddo,^[22] described the importance of "preserving nature"; much of this early emphasis had its origins in Christian theology. By the early 1800s biogeography was ignited through efforts of Von Humboldt, DeCandolle, Lyell and Darwin;^[23] their efforts, while important in relating species to their environments, fell short of actual conservation.

The term conservation came into use in the late 19th century and referred to the management, mainly for economic reasons, of such natural resources as timber, fish, game, topsoil, pastureland, and minerals, and also to the preservation of forests (see forestry), wildlife (see wildlife refuge), parkland, wilderness, and watersheds. Western Europe was the source of much 19th century progress for conservation biology, particularly the British Empire with the Sea Birds Preservation Act 1869; however, the United States began making sizable contributions to this field starting with thinking of Thoreau and taking form in the United States Congress passing the Forest Act of 1891, John Muir's work and the founding of the Sierra Club in 1895, founding of the New York Zoological Society in 1895 and establishment of a series of national forests and preserves by Theodore Roosevelt from 1901 to 1909.^[24]

In the early 20th century the New York Zoological Society was instrumental in developing concepts of establishing preserves for particular species and conducting the necessary conservation studies to determine the suitability of specific locations that are most appropriate as conservation priorities; the work of Henry Fairfield Osborn Jr., Archie Carr and Archie Carr III is notable in this era.^[25][26]

By the early 1970s national and international governmental agencies became more active in the conservation of biodiversity. Notably the United Nations acted to conserve sites of outstanding cultural or natural importance to the common heritage of mankind. The programme was adopted by the General Conference of UNESCO in 1972. As of 2006, a total of 830 sites are listed: 644 cultural, 162 natural. The first country to pursue aggressive biological conservation through national legislation was the USA, which passed back to back legislation in the Endangered Species Act^[27] (1966) and National Environmental Policy Act (1970),^[28] which together injected major funding and protection measures to large scale habitat protection and threatened species research.

In 1980 a significant development was the emergence of the urban conservation movement. A local organisation was established in Birmingham, UK, a development followed in rapid succession in cities across the UK, then overseas. Although perceived as a grass-roots movement, its early development was driven by a burgeoning of academic research into urban wildlife. Initially perceived as radical, the urban movement's view of conservation being inextricably linked with other human activity has now become mainstream in conservation thought. Considerable research effort is now directed at urban conservation biology.

By 1992 most of the countries of the world had become committed to the principles of conservation of biological diversity with the Convention on Biological Diversity;^[29] subsequently many countries began programmes of Biodiversity Action Plans to identify and conserve threatened species within their borders, as well as protect associated habitats.

The late 1990s saw increasing professionalism in the sector, with the maturing of organisations such as the Institute of Ecology and Environmental Management and, more recently, the Society for the Environment.

Since 2000 the concept of landscape scale conservation has risen to prominence, with less emphasis being given to single-species or even single-habitat focused actions. Instead an ecosystem approach is advocated by most mainstream conservationist, although concerns have been expressed by those working to protect some high-profile species.

The science of ecology has clarified the workings of the biosphere; i.e., the complex interrelationships among humans, other species, and the physical environment; moreover, the burgeoning human population, and associated agriculture, industry and its ensuing pollution have demonstrated how easily ecological relationships can be disrupted.^[30]