УРЛАГ
ГОО САЙХАН БА ЭРҮҮЛ МЭНД
ГАРААР ХИЙСЭН
СОЁЛ БА ТҮҮХ
ҮЗВЭР НААДАМ
БАЙГАЛЬ ОРЧИН
ХООЛ БА УНДАА
УРВУУ ИНЖЕНЕРЧЛЭЛ
ШИНЖЛЭХ УХААН
СПОРТ
ТЕХНОЛОГИ
ӨМСДӨГ ХЭРЭГСЭЛ
Sampling Invertebrates: Pitfall Traps and the Beating Tray
Most of the animals in any habitat are small, numerous and out of sight. You cannot quadrat them because they move, and you cannot mark-recapture most of them because there are too many — so you sample the ways they move instead.
A pitfall trap is a container sunk level with the soil that ground-active animals fall into as they walk. A beating tray is a pale sheet held under a branch that is struck sharply, so everything clinging to it drops onto a background where it can be seen. Between them they cover most of the invertebrates you will meet.
Neither gives you a population. A pitfall catch measures ACTIVITY-density — how many animals walked past — so a fast-moving beetle is over-represented and a sedentary one barely appears. Knowing exactly what your trap is measuring is the whole difference between a result and a pile of animals.
Анхан шат
3 days
Зааварчилгаа
1
1
Set the pitfall rim exactly level with the soil
Set the pitfall rim exactly level with the soil
Dig a hole, sink a smooth-sided container so its rim is EXACTLY flush with the surface, and firm the soil back against it so there is no gap or lip.
A rim standing a few millimetres proud is a wall that most ground beetles will simply walk around, and one set low creates a moat that funnels others in. Either way the catch reflects your digging rather than the fauna. Use two nested containers so the inner one can be lifted out without disturbing the hole.
Энэ алхмын материал:
Шилэн сав10 ширхэгШаардлагатай багаж:
Цэцэрлэгийн бяцхан хүрз
Шугам2
2
Cover it, and decide whether to kill
Cover it, and decide whether to kill
Set a flat stone or a tile on small pebbles a few centimetres above the trap to keep rain and birds out while leaving the gap open at ground level.
A dry trap catches animals alive, which is kind and lets you release them — but the predators eat the rest before you return, so you must check it every few hours. A preservative catches everything and can be left for days. For a first survey, use dry traps checked morning and evening, and only take specimens you genuinely cannot identify alive.
Энэ алхмын материал:
Зузаан цаас10 ширхэг3
3
Lay a grid of traps, not one trap
Lay a grid of traps, not one trap
Set at least five traps in a regular grid or along a transect, several metres apart, and treat each one as a separate sample.
Invertebrate catches are extremely variable — one trap beside an ant nest can hold more animals than the other four together — so a single trap tells you almost nothing. Several traps let you quote a mean AND a spread, and the spread is what tells you whether the difference between two habitats is real.
Энэ алхмын материал:
Шилэн сав10 ширхэг
Хэмжилтийн туг ба шонгийн иж бүрдэл1 багцШаардлагатай багаж:
Соронзон хэмжих туузан шугамЦэцэрлэгийн бяцхан хүрз4
4
Use a beating tray for everything above ground
Use a beating tray for everything above ground
Hold a pale sheet or an inverted pale umbrella under a branch and strike the branch sharply three times with a stick. Do not shake it.
A sharp jar dislodges animals that are clinging; shaking gives them time to grip harder or fly. Standardise the number of beats and the branch size and write them down, because 'a good shake' is not a unit. A pale background is what makes small dark animals visible, and it is why a white sheet outperforms a better net.
Энэ алхмын материал:
Хөвөн муслин даавуу2 metre
Модон дэгээ (дюбель)2 ширхэгШаардлагатай багаж:
Томруулагч шил
Хямсаа5
5
Sort, count and release promptly
Sort, count and release promptly
Tip the catch into a shallow tray, sort into groups with a soft brush or forceps, count, and release near the capture point.
Sort to whatever level you can defend — 'ground beetles', 'spiders', 'woodlice' is far more useful honestly recorded than uncertain species names. Keep the animals cool and shaded while you work; a plastic tray in the sun cooks a catch in minutes, and a survey that kills its subjects unnecessarily has failed at something more important than counting.
Шаардлагатай багаж:
ХямсааТомруулагч шил
Хээрийн тэмдэглэлийн дэвтэр6
6
Activity-density, diversity and comparing two habitats
Activity-density, diversity and comparing two habitats
Jupyter дэвтэр ачаалж байна…
Шаардлагатай багаж:
Хээрийн тэмдэглэлийн дэвтэр7
7
Take the traps out when you have finished
Take the traps out when you have finished
Lift every trap, fill the holes, and remove the covers.
An abandoned pitfall trap goes on catching and killing for months, and an open hole is a hazard to small mammals. Count your traps out and count them back in. This is the least interesting sentence in the batch and the one most often ignored.
Шаардлагатай багаж:
Цэцэрлэгийн бяцхан хүрзХээрийн тэмдэглэлийн дэвтэрМатериал
5- 10 ширхэгТүр орлуулагч
- 10 ширхэгТүр орлуулагч
- Түр орлуулагч
- 2 metreТүр орлуулагч
- 2 ширхэгТүр орлуулагч
Шаардлагатай багаж
6- Түр орлуулагч
- Түр орлуулагч
- 1 vendor sell this, none ship to you yetТүр орлуулагч
- Түр орлуулагч
- Түр орлуулагч
Холбоотой загварууд
Эдгээр загварууд мэдлэг хуваалцдаг — арга техник, материал эсвэл зарчим
CC0 Нийтийн домэйн
Энэ загвар CC0 дор гаргагдсан. Та зөвшөөрөл авахгүйгээр хуулах, өөрчлөх, түгээх, ашиглах боломжтой.
Загвараар дамжуулан бүтээгдэхүүн худалдаж авч Бүтээгчийг дэмжээрэй Бүтээгчийн шимтгэл Борлуулагчаар тогтоосон, эсвэл энэ загварын шинэ хувилбар үүсгэж орлогоо хуваахын тулд өөрийн загварт холбоос болгон оруулна уу.