lecture 7- conserving populations and species Flashcards
flamingo ex of pops fluctuating naturally
• Ex. Flamingos in africa - bars represent rainfall
○ Size of bubble corresponds to the amount of recruitment - empty bubble means no recruitment
○ Rainfall often drives population numbers by changing the availability of organisms that require water -ex feeding on lots of invertebrates that are available bc of more rain
○ Observational study - no manipulation
○ Across 60 yrs
why are long studies important
○ These kinds of data sets are foundational - if you don’t have a good length of time of observation, you don’t have an idea of how the population dynamics change over time
○ Pulses - variability in the amount of chicks hatching in any given year
○ Lots of ecological studies are done in the amount of time proportional to funding - ex. Funding for 4 years = study runs for 4 years
information that could help conserve a species at risk ?
- Environment
- Distribution - typically with things that are more cryptic (plants, insects) - hard to assess a species without having a knowledge of their distribution
- Biotic interactions
- Morphology
- Physiology
- Demography
- Behavior
- Genetics
- Interactions with humans
caribou ex of using traditional knowledge
• Objective: to understand long term patterns in caribou population changes for several herds in NWT
• Problem: Need long set of data to understand a population - how do we extend our knowledge to before people recorded the knowledge
• How can we use different kinds of data to assess a population?
○ For the caribou - looked at current extant trees for scaring by caribou - is recorded in the tree ring (a concentration of pigment where there was previous scaring)
○ Consulted with tiucho first nations elders to find locations where caribou travelled, then took samples from trees to look for scaring data and analyze rings
○ With enough trees + scars, you can estimate the abundance of caribou at any given time based on the amount of trees with scaring present
○ Takes a long time to core the trees - by consulting with the elders, the general migration patterns of the caribou were identified (sampling area) - based on the smaller sampling area, a system of coring and analyzing the trees gave enough data to estimate abundance in the past
○ Add time series graph here
○ Based on that data - time series constructed and we can see how the populations of caribou fluctuated over time
○ When you look towards now, the abundance estimates are towards the extreme ends of the negative residuals of this time series - we can tell that the fluctuation is far beyond the natural decline levels - evidence of human impact
○ Limitations: the numbers are estimates
• Study of penguins in South America
○ Radio collared the penguins
○ Shows you the range of the penguins
Gives you a sense that conserving these penguins extends into international waters - spatial scale of the problem: not just terrestrial breeding sites but also indirect impacts into the marine habitat (via fishing, etc)
when is collar work used + why
• Collar work is typically done with larger animals
○ They tolerate it
○ Larger organisms tend to move more and are harder to keep track of
○ Also have a removal mechanism - can be set to release automatically or be released actively
how are smaller organisms studied?
• With smaller organisms
○ Still lots of use of mark and recapture methods
§ Individuals captured, marked, released, then recaptured to estimate population size and range
§ Also gives an idea of the abundance of a population
○ Genetic approach
Traps to collect hairs, etc. then conduct a deep analysis
how is info communicated to make long term studies feasible
• Recognition that there is a value in combining people’s resources and understanding things on a larger scale
• Long term projects/organizations to connect groups = can sustain the necessary work to continue long term studies
• If a study is publicly funded, it needs to be publicly available - can be referenced
• Network monitoring
○ Big push for it starting about 2 decades ago
○ Currently, networking is much easier due to technology
• What do we do with information from long term studies
• Population viability analysis • Minimum viable population • Long-term monitoring • Assign conservation categories Assign legal protection
what is PVA - Population viability analysis
- General category of analyses - “backbone” of conservation studies
- Goal: mathematical analytical assessment of how a population will do in the future - viability
describe PVA in detail
• general and common study that estimated how the population will do in the future. They do projections, seeing the likelihoods, working with possibilities to see how the population will change with time based on the information you have- birth rates, longevity, abundance of population, fluctuates over time etc. but we can only project so much, because after a longer time there is more noise in the data.
• Interested in looking at sensitivities in a model - ex. What happens to this pop. If you remove 10% of the habitat?
○ Can overlay other factors onto it as well - ex. What happens if you lose 10% of habitat but protect only juveniles?
• Ultimately: will get a set of possibilities that are factorial
• Drawback: focus on the range of factors that are most critical - the assumptions you make will impact the conclusions you draw from PVA
what is the MVP?
A miniumum viable population for any given species in any given habitat is the smallest isolated population having a 99% chance of remaining extant for 1000 years despite the foreseeable effects of demographic, environmental, and genetic stochasticity, and natural catastrophes
what affects the mvp? why is it needed?
• The MVP depends on the % chance of survival (higher chance of survival = higher MVP required) and the number of years you want it to persist ( higher number of years= higher mvp)
• Rare species can be rare bc they are rare over a large area or only exist in a small area, or have pops. That are small = vulnerable
• Hard to make a plan to conserve a species without knowing MVP
○ If above mvp - might be able to survive in a zoo etc. , but not in nature
extinction deficit?
in nature
• Extinction deficit - there might be lots of species that are already under MVP that we don’t know are inviable
• Not absolute values!! These are projections ○ probabilities - prepare accordingly (ex. If there is an 80% chance of rain tomorrow, you will take an umbrella with you)
• Minimum dynamic area models?
• Can use these models to estimate the amount of area needed to conserve/protect populations
○ Based on area used and how they use it
• The larger the habitat, the more populations can progress in their natural dynamic
• For conservation, habitat protection is often the most important
Given natural conditions that are spatially sufficient = species survive
