BIOL2024 Revision Notes PDF

**INTRODUCTION** \- Know the basic principles of the science of ecology \- Brief intro to phenology and climate change What is Ecology - The scientific study of the interactions that determine the distribution and abundance of organisms What do Ecologists do? - Seek patterns in complex...

**INTRODUCTION** \- Know the basic principles of the science of ecology \- Brief intro to phenology and climate change What is Ecology - The scientific study of the interactions that determine the distribution and abundance of organisms What do Ecologists do? - Seek patterns in complexity of nature (look for order in natural world) - Describe the patterns (collection of data, observations - The what and where type questions - Requires rigorous sampling methods - Repeated patterns builds predictability - Explain the patterns (hypotheses to predict patterns, experiments to test hypotheses) - The how and why questions - Seek causes, mechanisms and functions Components of biological systems that is looked at in this subject - Ecosystems - Communities - Populations - Organisms From highest to lowest \^ = increasingly complex + decreasing knowledge about function. Ecology and evolution - Darwin's theory of evolution by natural selection paramount - Nothing in biology makes sense except in the light of evolution - Natural selection is the ultimate why - Ecological patterns today are result of evolutionary process in the past + interactions with current environment Natural History and Ecology - Naturalists observe nature - All living things, physical conditions in which they live, their interactions with each other - Basis of all ecology - Ecologists aims to explain the observations Ecology and Scientific Method - Observations - Hypotheses - Predictions - Experiments - Statistical tests - Refinement of hypothesis Applied Ecology - Ecology of human disturbance - Use of ecological theory and principles to explain and manage human impacts - Ecology in environmentalism - Environmentalism is a social movement, not science, not ecology - Highlights environmental issues - Should be based on ecological observations - Does not explain the natural world - Not all ecology is conservation based - Ecology in conservation - Conservation biology built on ecology - Reasons for species rarity + decline are ecological q's - Legal protection mechanisms built on ecology Phenology - The study of cyclic and seasonal natural phenomena, especially in relation to climate and plant and animal life - Changes over time **ECOSYSTEMS** 1\. Be familiar with the major biomes and where they are located 2\. Understand the patterns of biomes in relation to temperature, precipitation and elevation 3\. Be familiar with the patterns of temperature and precipitation across the Australian continent 4\. Understand the greenhouse effect and the evidence for global climate change 5\. Know examples of phenological responses to climate change and how the data were recorded Major World Biomes - Biomes are distinctive associations of vegetation and animals, describing large-scale ecological variation - Primarily shaped by climate (temp + precipitation) - Similar biomes on different continents look similar, but the species will be diff in diff parts of the world as they have diff evolutionary histories - Ecologists use biomes as a convenient way of categorising areas of the world (but they do not necessarily have specific boundaries) Types of Biomes - Forest - Savanna - Desert - Tundra - River - Old-growth forest - Mangrove - Steppe - Island - Grassland - Wetland - Swamp - Plain - Shrubland What causes global patterns (biomes) - Rainfall Broader influences on where/when/why it rains - Angle of incidence varies due to tilt of the Earth - Temperature + rainfall influenced by solar radiation and atmospheric processes - Variability of rainfall is a dominant feature on much of the Australian continent - Precipitation - Elevation - Soil types Understanding environmental change as types of disturbance - Environmental fluctuations - Fire in temperature woodlands, forests + grasslands - Droughts in terrestrial biomes - Storms and cyclones events on coasts - Floods and droughts in rivers + streams - Human impacts Patterns of disturbance - Scale - Large scale (e.g. storms) - Small scale (e.g. turning over a rock in the intertidal zone) - Frequency - One event or pulse (e.g. an oil spill) - Continuous (e.g. eutrophication, climate change) - Periodic (e.g. storms, fires) - Changes composition of communities Climate vs Weather - Weather - Short-term conditions (incl. sunshine, rain, cloud cover, winds, snow, thunderstorms - Can change minute to minute, day to day - Climate - Avg daily weather for an extended period of time - Long-term pattern of weather in a particular area The Greenhouse Effect + The Main Lines of Evidence for Global Climate Change - Greenhouse effect = natural, important for life on Earth - The natural warming of the earth by heat trapped due to the presence of heat-absorbing atmospheric gases - Greenhouses gases (CO2, N2O, CH4) + water vapour warm the lower atmosphere + provide conditions suitable for life on Earth - Burning of fossil fuels (coal, oil, natural gas) have \^ conc.s of these gases in the atmosphere - Ozone in the lower atmosphere and CFC's also act as greenhouse gases - Climate change = human driven - Greenhouse gas emissions have increased since the Industrial Revolution, driven by economic + population growth - CO2 levels are increasing at an overwhelming rate - Leads to increase in the freq of extreme heat events + changes to rainfall timing + volume Data on Past Climates Scientists gather data on past climates by several methods - Tree ring widths record past climate (dendroclimatology) - Ice cores - Gas bubbles trapped in the ice contain chemical cues that reveal past temps. The same bubbles tell us the concentration of atmospheric gases, incl. greenhouse gases such as co2 + methane. Other material found in the ice, such as pollen, dust, and ash, provide info about sea level, precipitation, (see lecture sides) - Keeling Curve (measured conc. of CO2 in the atmosphere taken daily since 1958 - CO2 conc. haven't been over 300ppm in the last 800k yrs, except 1960. Humans evolves 300k yrs ago. Causes of Climate Change - Energy consumption - Transport emissions - Agriculture - Industrial processes and product use - Waste Phenology and Climate Responses - Phenology records can be a proxy for climate change - Temperature in particular influences small changes in timing of biological events - Things that change: - First events (e.g. flowering, breeding, nest w/ eggs) - Last recorded events (e.g. migrating individual) - Peaks events (e.g. flowering) Phenological changes 1. Early warning indicators - Phenology shifts 2. Complexity of ecological changes - Abundance (\^ + decreases) - Opportunity for growth (growing season length) - Morphology shifts - Range shifts (latitudinal or altitudinal) 3. Final non-reversible changes - Extinctions - Loss of diversity **VEGETATION** 1\. Be familiar with the concept of a plant community + the differing views on whether communities are natural units or constructs of convenience 2\. Understand the patterns of vegetation in Australia at the local (Sydney) and regional scales 3\. Know how to use the vegetation classification schemes of 1) Specht, 2) Beadle & Costin & 3) Forest types 4\. Understand vegetation structure and how it relates to habitat features that support a diversity of species 5. Know the methods used for vegetation mapping Plant Community - Ecological communities: groups of organisms (plants, animals, fungi) living + interacting in the same place at the same time - Assemblages: phylogenetically related groups within a community (e.g. eucalypt woodland) - Vegetation: may be divided into distinct units of intergrade with no clear boundaries (whether plant communities are real entities that can be mapped has been debated - Important: decisions about land we use often rely on vegetation maps - A scheme for grouping sets of species into communities, guilds, and ensembles based on the combination of geographical location, common ancestry, and shared resource use. Why We Should Care About Vegetation Concepts Vegetation community definitions have real consequences - Vegetation communities need to be defined to have legal protection - Are often the bases for conservation planning as they predict where species live (e.g. koalas) - Are frequently the basis for land-use planning (where conflict may occur) Vegetation Classification Comparing two schemes for Australia - Beadle & Costin: based on plant formation - Specht: simple to use based on structural attributes (woodiness, height, projective foliage cover) - Projective Foliage Cover: describes the area of ground (%) which is covered by the foliage of the dominant plants - Finding a height: using a clinometer or using estimates - Leaf characteristic - Mesomorphic: - Soft thin leaves - Thin cuticle - Predominantly horizontal - Typical of rainforests - Sclerophyllous - Hard, thick, leathery - High lignin and fibre - Vertical, pendulous - Dry Sclerophyll Forest - Specific leaf area - Measure of leaf thickness - SLA = leaf area (\$cm\^2\$)/leaf mass (g) - Area measured as a projected area by leaf area machine - Mass is dry mass of same area of leaf - Replicate leaves are used for estimates Vegetation Structure - LiDAR (Light Imaging Detection and Ranging): enables vegetation structure to be recoded in great detail and used in a variety of application for measuring biomass or carbon in a forest Vegetation Mapping and Classification Floristic surveys - Systematic techniques to minimise observer bias - Ensure final classification is explicit and repeatable - Survey sites stratified to represent: 5 geological substrates, 3 temperature zones, and 4 rainfall zones - Place plots in representative areas - Note previous classification was based on subjective interpretation of floristic patterns by experts Data recorded in each survey plot - Presence of all vascular plant species - Cover/abundance of each species on the Braun-Blanquet scale from 1-7 - Structural layers (tree, small tree, shrub, forb) - Height range of each layer - Projective foliage cover Hierarchical classification - Based on each cover/abundance scores for each species - Similarity among samples calculated - Clustering technique used to look for patterns - Dendrogram produced Lecture Summary - Ecological communities are groups of organisms living in the same place at the same time - Assemblages are phylogenetically related groups within a community - Vegetation may be divided into distinct units or it may integrate with no clear boundaries - Vegetation maps are models of how plant species are distributed - Mapping starts with plot samples of plant composition, classification of similarity, correlation to environmental variables, aerial photographs to extend the map units spatially and to complete the mapping - Maps can be out of date due to disturbance, clearance or new classifications **FORESTS** 1\. Be familiar with the forest types in Australia and where they are located 2\. Understand what makes Australia's rainforest types distinctive and appreciate why the canopy was considered a new frontier of discovery 3\. Be familiar with temperate rainforests, their locations, and the Tarkine, as a case study of diversity in Australia 4\. Be familiar with the Greater Blue Mountains World Heritage area 5\. Understand the principles of sustainable harvests as it applies to fisheries or forest 6. Understand the issues of invasive species and how we can study them Australia's Rainforest Types Australia's Wet Tropics - Less than 0.2% of Australia + 2% of our forest area - Incredibly biodiverse (species rich) despite relatively small area - many species not found anywhere else (endemic) Gondwana Rainforests - QLD, NSW - Extremely high conservation value - 200 rare or threatened plant + animal species - Similar species to rainforest of Gondwana - High altitudes Underground orchid - No leaves + no chlorphyll - Depends entirely upon symbiotic fungus for survival - Flowers appear in leaf litter - Pollination by small flies or insects - One of only four flowering plants on Earth to complete its life cycle entire underground - Seed dispersal possibly by bandicoots + wallabies Temperate Rainforests and the Tarkine Tarkine - Anglicised pronunciation of an Aboriginal tribes from western Tasmanian coastline → 2nd largest expanse of temperate rainforest in the world - Defined an an unbounded locality by the government - Name not used in maps, but has been used a subject of contention between conservationists + mining/logging interests Tarkine Treasures - Australia's largest remaining single tract of temperate rainforest - Rainforest is mainly Gondwanan species - Mosaic vegetation of communities, incl. woodland, wetlands, dry sclerophyll forest, etc. - High diversity of non-vascular plants (mosses, liverworts + lichens) - Provides habitat for over 100 threatened species of flora + fauna - 80% is protected from logging, only 5% is protected from mining Eucalypt Forests in the Greater Blue Mountains World Heritage Area World Heritage-listed areas - Important natural + cultural heritage - 1223 sites in 168 counties protected by international convention - 20 sites in Australia The Greater Blue Mountains Area - Australia's eucalypt vegetation - Adaptability + evolution in post-Gondwana isolation - Wide + balanced representation on eucalypt habitats - 90 eucalypt taxa - Representation of all four groups of eucalypts occur - High level of endemism - Evolutionary relic species which have persisted in highly restricted microsites Ecosystem Services Trees Provide - Keep us alive + healthy - Provide medicines - Store carbon, taking carbon dioxide out of the atmosphere - Provide many diff kinds of food Sustainable Harvests - Managing a biological resource - Logistic + exponential population growth - Maximum sustainable yield - Bioeconomic theory - Crash of Anchovy fishery - Tragedy of the commons - Australian forests Managing a biological resource - Exploited populations are harvested to provide a resource - Based on population ecology - Can be sustainable if we only remove the surplus production from the population Bioeconomic theory - Interactions of economic + biological systems - Aim: Harvest for maximal social + economic benefit - Dilemma: - The value of a resource is discounted through time - If high short term profit is the goal then it can lead to over-exploiting the resource to point of extinction - Mobile species As the resource diminished its catchability + hence profitability decreased so switch to a different species - Species in small areas or sessile Reduced population size does not necessarily decrease profitability so they may be harvested to extinction Tragedy of the Commons - Commons: any resource shared by a group of people (land, water, air) - Benefits for the individual - But the costs are shared communally → as the population grows + greed runs rampant, the commons collapses - No incentive to conserve - Solution is to have regulated use of resources Invasive Species \*Pinus radiata\* - Widespread use as a timber tree - Invading native forest in Australia - Listed as a weed species - Control possible but not usually undertaken - Yellow-tailed black cockatoos - Eat seeds out of cones - Important long-distance dispersal agent **URBAN ECOSYSTEMS** - Urban ecology - Global approaches - Defining cities - Urban-rural gradients - Heat Islands + rainfall patterns - Responses to pollution - Sydney as case study - past/present/future - The glass half empty - Loss of biodiversity in cities - Degradation of ecosystems in cities - Drivers of change - The glass have full? - Restoration of endangered communities \* Nature's classroom and our wellbeing - The future - ecology in, of and for cities UN Sustainable Development Goals - Sustainable cities + communities - Life below water - Life on land Conventional wisdom - The conservation of natural systems in cities (+ the services they provide) is often dismissed as a hopeless cause - From a restoration perspective: action is good, but it is the results of such action that matters more Classifying Cities - General - Size - Static vs growing - Growth rate (slow/fast) - Idiosyncrasies - Economic context - Latitudinal effects Scope + scales of place-based approaches - Threatened species - Iconic species - Floral visitors: landscapes + local habitats - Biodiversity + threats to human health - Ecology of invasion + recolonisation - People + nature in cities Urban-rural gradients - Gradient of ecological pattern + function moving away from an urbanised area - Land cover proportions - Land cover patterns - Species assemblages - \% impervious surface - Generally linear transects - Key hypothesis: do they vary in a predictable fashion w/ increasing distance from the city centre? Cities as hostile places for nature - Fragmentation - Area effects - Edge effects - Isolation - Heat island effects - Nutrient input - Invasive species - Pollution (atmospheric, water, light, noise) - Disturbance regimes (lack of fire, overuses, etc.) Urban heat island effects + insect plant interactions - Increased urban development + reduced vegetation cover - Increase in impervious surfaces Pollution - Atmospheric - NOx + ozone - Dust - Water - Light - Changes in behaviour + massive mortality - Noise - Altered songs + disrupted breeding for birds, mammals, frogs + grasshoppers Effects of pollution on plants + animals - Plants in urban ecosystems are exposed to pollutants + higher temps - Urban bees take longer to learn + forget more quickly Pollution + Plants - Urban plant biomass was 2x that of rural sites - Ozone (O3) was the major driver of change by excluding other possible factors (i.e. soils, temp, CO2, nutrient deposition, urban air pollutants + microclimatic variables - Higher rural ozone \$O3 exposures reduced growth at rural sites (consequence of nitrogen oxide scavenging in urban areas) Urbanisation affecting natural systems Sydney case study - Urban remnants support a diff invertebrate fauna to larger continuous area of similar vegetation - Dominant trees in urban remnants suffer higher levels of insect damage than in larger continuous areas - Loss of higher trophic levels from urban remnants, particularly small birds may contribute to the declining state of vegetation in urban environments - Disruptions to fundamental ecological processes may be indicative of the biotic state of these remnants Sydney's urban remnants - Substantial reduction in area of natural vegetation since 1788 - Anthropogenic pressures on remnant vegetation - Several vegetation types found only in urban remnants have high conservation significance - Ecological consequences of urbanisation Biodiversity loss impairing function in urban ecosystems Inverts in the Urban ecology toolbox - Multiple sampling methods to survey range of groups of ecological processes central to biodiversity/ecosystem function - Functional group approaches - Amenable to experimental approaches Insect-plant interactions - Shift focus from assessments of diversity to functions - Terrestrial arthropods - Herbivory - Regulation of herbivores - Seed dispersal - Pollination - Decomposition Terrestrial invertebrates and urban fragments - No diff in species richness in small + large - Smell remnants supported fundamentally diff faunal assemblages - Parasitic wasps showed most dramatic shift in composition - Functional groups of ants affected by fragment size- generalists + opportunists more prominent in smaller remnants Trapping/survey techniques - Beating/sweeping (from vegetation) - Pitfall traps (active ground-dwellers) - Yellow pan traps (wasps) - Direct searches - Light traps Herbivory in urban remnents - Higher levels of total herbivory caused by several diff eucalypt 'pests' - Higher levels of herbivory are consequences of release from predation in urban remnants - Decoupled ecological interactions as a major stressor in urban ecosystems Ecological restoration - Examining remnants, pastures + restored areas - Surveying invertebrates - Experimental work - Pollination - Seed dispersal - Parasitism + predation - Herbivory Climate change + urbanisation Embracing novel ecosystems - Accepting the new assemblages of species within these landscapes - Lowering the bar on what can be expected to maintain Urban greenspace - combating urban heat island effects + climate change - Surveys, focus groups, + field interviews of residents in Aus + NZ - Wellbeing not tied to what exists, but what we think exists - Compromising for what green already exists - Importance of nature near people - The case for accessible + inclusive nature, nature connectedness, + links to human health The future - Ecological interactions in novel ecosystems - Intense selection pressures + urban adapters - Integrate landscape + organismal traits to predict impacts of urbanisation - Celebrate the vestiges we have - Conserving extant e.g.'s - Restoring what we can - Using what we have to engage + educate **WOODLANDS** 1\. Be familiar with the bioregions and where they are located 2\. Appreciate the importance of Eucalypt woodlands for flora and fauna 3\. Know how basal area of trees is measured and its relationship to tree biomass 4\. Appreciate fire ecology: fire regimes, fire behaviour, fire intensity, fuel loads, plant responses to fire, benefits and limitations of prescribed burning 5\. Be familiar with Acacia open woodlands using a case study of Brigalow, *Acacia harpophylla* and its importance for endangered fauna Bioregions - Are large, geographically distinct area of land with common characteristics such as geology, landform patterns, climate, ecological features and plant + animal communities - In Australia, there are 89 bioregions - 419 IBRA subregions National Reserve System - Underrepresented Bioregions in Australia - Underrepresented Subregions Eucalypt woodlands - Eucalypts are dominant canopy species, widely spaced - Understorey in the east mainly grassy, while in the west are shrubby → variation in understorey structure + species reflects the range of climatic zones + site conditions supporting these open woodlands - Highly fragmented + extensively cleared for crops + pasture → sheep-wheat belts Fauna Requiring Eucalypt Woodlands - Koala - Typically inhabit open Eucalypt woodlands, + the leaves of these trees make up most of their diet - Koalas were widespread in Aus → esp. VIC + NSW - Land clearance + burning, destroyed much of their natural habitat + \^ no.s of koalas were killed for the fur trade - Status changed from vulnerable → endangered The Great Western Woodlands (GWW) - Biome: temperate woodland - 160,000 km\^2 - Global diversity hotspot - 20% of all Aus's known plant species - Haven for communities of animal species incl. many of the birds once typically found in temperate woodlands, but now declining in other parts of Aus (e.g. malleefowl) Description: - Stocky ground-dwelling Aus bird abt the size of a domestic chicken - Large nesting mounds constructed by the males - Lack of parental care after the chicks hatch Threats: - Clearing of habitat - Fox predation - Grazing - Inappropriate fire regimes Basal Area of Trees - A measure of how big a tree is - The cross-sectional area of a tree trunk measured at breast height over bark - Stand: an area of forest that can be identified + mapped according to broad forest type + height class - Standard basal area: the sum of the basal area of all live trees in a stand, + is usually expressed in m\^2/ha DBH = Diameter at Breast Height - Basal area is measured as DBH - Usually measured in cm - Step 1. convert diameter to area: Area of a circle = pi(radius)\^2 pi = 3.142 BA = pi(DBH/2)\^2 - Step 2. adjust from cm to m Basal area = pi(DBH/200)\^2 Basal area + biomass - Basal area, tree height + the taper of trunk, can be used to estimate tree biomass - Greater basal area = greater biomass, or bigger trees Fire ecology Key messages - Climate change is causing hotter + drier conditions - Fires are larger + more intense = megafires - Prescribed burning does not stop catastrophic fires - Fire regimes are needed to manage for biodiversity Fire and sclerophylly Fire is common in Aus + its incidence is strongly associated with sclerophylly - Environments w/ higher heat load - Lower rainfall - Soils w/ low nutrients, especially P - Locations exposed to wind - Recycling of minerals w/in plant tissues - More fibre (lignin) + low protein in litter - Litter which breaks down more slowly Fire defiinitions - Intensity of a fire: bushfire, wild fire, firestorm - Vegetation in which fire occurs: forest fire, scrub fire, brush fire - Whether the fire was planned: prescribed fire, controlled fire, hazard-reduction fire, cool-season fire - Head fire - Back fire - Fire fighting operation terms: back burning, burning off, burning out Fire regime - Frequency - Intensity - Season - Extent (spatial distribution) - Type of fire - Fire interval: length of time between 1 fire + the previous fire - Fire period: the fire interval averaged over a no. of fires Ecological fire regimes - Consider life history characteristics of the plants + animals that make up a community - Characteristics enabled the species to coexist w/ a fire regime over 10000s yrs + should reflect what the species can tolerate - Tolerable Fire Interval: the time after the species reaches reproductive maturity + b4 the time of senescence (old age) when production ceases - Determined by the attributes of a species - If a fire occurs b4 or after these stages, may prevent recovery of the species at a site, at least in the short term - The tolerable fire interval will vary for each species in a locality → fire has to be managed wisely Fire behaviour - The physical attributes of individual fires - Height + depth of the flames - Speed with which the fire moves - Size + shape of the various fonts - Intensity of the fire - Many of these attributes can be inferred from post-fire features of the burnt landscape - \^ winds, \^ temps, + low humidity encourage the spread + intensification of fires Fire intensity - Low intensity fire mostly \ - Plankton are an important food source - Plankton is at the base of most marine food webs - Basis of life on earth → photosynthesis + phytoplankton - Zooplankton + larvae basis of fisheries - Development: - Indirect: young do not look + feed similar to adults - Direct: young look + feed similar to adults **Development** **Location** -------------------------------------------------------- --------------------------------------------------------------------------------------------------------------- Indirect (e.g. oysters) External: eggs + sperm released to outside called broadcast spawners, development in plankton Indirect (e.g. some molluscs copulate by penis) Internal: release immature stage, development in plankton Indirect (e.g. barnacles + crabs copulate w/ a penis) Internal: some development + then release at a more advanced stage, development in plankton Direct development (e.g. squid, copulate with a penis) Internal: development of larvae into advanced juvenile stage, can be in egg masses on the benthos or internal Larvae - Many marine organisms have dispersive planktonic stage known as larvae - Size: - \ - Larvae importance - Larvae are ecologically important as the foundation stage of many marine populations - Basis of fisheries - Invasive species + species w/ high population no.s can alter ecosystems - Larvae are being impacted by climate change - Changing larval distributions, altered fisheries + concerns for species conservation - Vulnerable to climate change e.g. ocean acidification Fertilisation + location of development - Broadcast spawners: fertilisation occurs in the water column or near the benthos - Benthic egg masses: fertilisation occurs in the benthos w/ eggs deposited + then male fertilises the eggs or by copulation + fertilised eggs are deposited - Brooders: release their eggs into chambers on or in their body where fertilisation + development occurs → some lay benthic egg masses which are cared for Bi-phasic life cycles planktonic larval stage + benthic juvenile + adult stage 1. Barnacles - Hermaphrodites: male + female organs - Transfer sperm, eggs are fertilised - Nauplii release + feed - Metamorphose to a cyprid, doesn't feed - Cyprid returns to adult habitat, metamorphoses into juvenile barnacle 2. Crab life cycle - Separate sexes, copulate modified leg (pleopod) - Fertilised eggs passed to ventral abdominal surface - Brooded - Hatching stage - zoea, feed metamorphoses to a megalopae - Megalopae returns to adult habitat 3. Copepods - Body pear-shaped (thorax + abdomen fused) - One medial eye, 2 prs antennae - Swim using legs + antennae - Sexes separate - Nauplii released as larvae - All time spent in water column 4. Cnidarians - E.g. corals + anemonies → benthic adults + planktonic larvae 5. Polychaetes - Marine worms - Sexes usually separate - External fertilisation (swarming behaviour) - Trochophore larvae stage, metamorphoses into a veliger, metamorphoses into a juvenile 6. Echinoderms: - Sea urchins + sea stars - Diverse larval forms **MARINE HABITATS -- ESTUARIES** 1\. Define the different types of estuaries are 2\. To be able to describe the different regions of estuaries and key features (Case Study Sydney Harbour) 3\. Understand the importance of estuaries as supporting diverse habitat types for conservation 4\. Know what mudflats and sandflats are and the types of invertebrates that live in these habitats and their ecological roles 5\. Understand what is meant by coastal squeeze with saltmarsh and mangrove habitats as the examples 6\. Be able to describe the life history of a marine organism that uses nearshore and offshore habitats in its lifecycle (links to plankton lecture and practical exercise) Estuaries A body of water that is either permanently or periodically open to the sea and which receives at least periodic discharge from a river - Lie at the interface between marine, freshwater and terrestrial ecosystems - Are semi-enclosed bodies of water connected to the open sea - Influenced by marine, freshwater and terrestrial processes - Seawater is diluted with freshwater derived from land drainage - Salinity declines gradually from the seaside to upstream, but on a daily basis with tides and wind conditions can change rapidly - Temperature and salinity can vary widely seasonally and daily (e.g. tides) can be impacted by environmental factors such as flooding and heatwaves Types of Estuaries - Drowned in river valley - Following the ice age (e.g. Sydney Harbour, Murray R) - Are common in southeast Aus → most large estuaries are this type - \^ in sea level flooded lower regions of river basins - Barrier - Estuaries with sand bars or barrier islands at ocean side (e.g. Lake Macquarie - Narrow entrance restricted by a barrier (navigation hazard) - Saline coastal lagoon - With intermittently open entrance (e.g. Lake Conjola) - ICOLLs: intermittently closed/open lakes + lagoons are a special feature of NSW - Tectonic - Estuaries formed along a fault line (e.g. San Francisco Bay) Estuaries have a variable marine/freshwater influence - Tides - Salinity Division of estuaries into zone/regions Each with variable environmental characteristics strongly influenced by the salinity gradient - Outer estuary (mouth) - Marine dominated → salinity as for adjacent ocean - Wave + tide energy → strong tidal movement - Clean sand or rocks - Central estuary - Mixed energy - Brackish water - Salinity 25-30 - Inner or upper estuary - River dominated - Low salinity - Head of the estuary where freshwater enters the estuary - River dominated - Low salinity → up to 100% fresh at times Other notes - Estuaries are highly productive habitats due to the input of plant material from mangroves, trees + seagrass beds (plant detritus) → terrestrial sources of nutrients - High levels of nutrients + phytoplankton supporting marine life - Large river systems lined by mangrove forests - Highly productive systems - Many animals depend on them at diff life stages - Many species spawn in estuaries incl. commercial species fish and prawns - Support ecologically + economically important species such as oysters + prawns - Are important in supporting oyster aquaculture + prawn fisheries - Support a diversity of species that are tolerant of fluctuating salinity and are specialist for brackish water conditions Environmental Concerns Due to their location + runoff from the land estuaries are prone to pollution + bc many are in urban location + are used for shipping + ports also have many introduced species Mudflats + Sandflats Characteristic intertidal habitat in regions w/ large tidal ranges → are well developed in Aus' tropical regions + are often located in the lower regions of estuaries - The surface layer of the sand or mud is oxidised + with depth oxygen decreases → dark mud → the anomic layer smells of sulphide - Supports infaunal species → burrow forming + burrowing → worms + molluscs + ghost shrimp (yabbies) - Bioturbation → the burrowing + feeding activity of these animals are a key habitat modifiers → important in aerating the sediment, sediment turn over the nutrient cycling - Other burrowers include solider crabs → these are locally abundant → feed + burrow in aggregations Sources of disturbance - The animal populations can be impacted by environmental conditions such as heatwaves, storms + floods - Infaunal animals are an important source of food for a diversity of species - Predation by wading birds, fishes, rays, crabs and other predators is a major disturbance → key for migratory birds - Yabby pumping for bait is a major human disturbance Mangroves + Saltmarsh Habitats Mangroves - Occur in the upper intertidal regions of estuaries + along sheltered open coasts - In tropical Aus mangroves are highly diverse w/ 35 species - Mangroves have aerial roots or prop root to facilitate air exchange - In NSW = 2 species (white + river mangrove) - In tropical regions species are diverse Distinct flora + fauna - Animals in mangrove habitats are distinct incl. a suite of snails + crabs that live in burrows in the mud at the base of mangroves - Diff snail species live at diff heights up the mangrove tree → as it is a vertical intertidal habitat + can move up + down w/ the tide → also means to reduce predation by fishes - In NSW an abundant barnacle lives on mangrove trunks + has been well studied → are preyed on by predatory snails - The seaweed Neptune's necklace is a very abundant around the roots of mangroves in estuaries Mangrove habitats - The intertidal is trees + leaves Barnacles + snail on mangrove trunks - The intertidal substrate is made of trees + leaves Barnacles on leaves - The shallow subtidal substrate is made of roots Coral on roots - Ecosystem services - Are highly productive + are an important source of plant material + detritus \^ nutrients → their roots help aerate the sediment - Play a major role in filtering water that runs off the land reducing the load of contaminants that enter water ways - The loss of mangrove w/ urbanisation has been very detrimental to marine water quality → losing mangroves amplified pollutants in runoff - Mangroves buffer shorelines against sea level ride, protect against erosion, shelter + food for marine life + provide a nursery habitat for many species (e.g. fishes + prawns) Saltmarsh - Endangered ecological community - Coastal saltmarsh is often found on the landward side of mangrove stands - Saltmarshes needed drier conditions than mangroves to survive and are characterised by the presence of succulent plants - These plants are specialised + diverse Mangroves + Saltmarsh Habitats → Environmental Concerns - Climate change - Drought in 2015-2016 = extremely dry weather from severe El Nino - Low water levels lasted \~6 months, + mangroves died of thirst - Bushfires → some of these coastal marine habitats were destroyed by bushfires - Coastal development - Mangroves have been cleared in many countries to reclaim land for urban development + for prawn farming - Stats - 50% of saltmarshes lost in estuaries worldwide - 35% of mangroves lost in estuaries - Coastal squeeze - Leads to loss of saltmarsh first **MARINE HABITATS -- BEACHES** 1\. Know what features are used to categorise beaches 2\. Know the types of invertebrates that live on sandy beaches and soft sediment habitats 3\. Understand the concept of bioturbation and the types of species that are bioturbators 4\. Understand the use of artificial units of habitat to investigate assemblages in different habitats and impacts of environmental stress a\. CASE STUDY: soft sediment biota as a case study - links to practical exercise Sandy Beaches - A wave-deposited accumulation of sediment lying between the modal wave base + the upper swash limit - Wave base: maximum depth at which waves can transport beach material shoreward - Swash limit: landward limit of wave action + sediment transport - Habitability varies depending on wave + wind climate = exposure - Beaches are classified by their energy regime - Sediment grain size is also important + reflect the energy regime - Most dynamic component in coastal system + are one of the harshest environments for organisms, but they can be abundant in the sediment - Sediment grain size exerts a strong influence on the type of resident species - Some abundant animals on beaches incl. crustaceans → important prey for fishes + birds → many shorebirds depend on invertebrates for food - Filter feeding bivalves are generally more conspicuous invertebrates at low tide levels on wave-exposed beaches → commercially fishes + are collected as fishing bait - Overfishing of bivalves is a problem → a major source of food for the Pied Oystercatcher (bird) → reason why the bird is of conservation concern Characterisation of beaches of Aus - Description of each beach physical characteristics w/ specific comments on its: - Surf zone character - Physical hazards - Suitability for swimming, fishing, surfing - Based on the physical hazards, all beaches are rated in terms of public safety + scaled from 1-10 (least-most hazardous respectively) Bioturbators - Animals that live in and on the sediment and by their activity disturb, mobilise the sediment, oxygenating sediments + recycling nutrients → very important for ecosystem health - E.g.: - Beach bubbles - Donax clams Beach Types - Dissipative beaches: - Large waves (+/or) find sand - Wide surfzone - Intermediate beaches: - Intermediate wave height, sediment size, gradient + surfzone width - Bars + rip channels - Reflective beaches - Low waves (+/or) coarse sediment - Short surfzone - Are where unique sea star species are found → narrow range epidemics in temp + tropical Aus Storm effects on temperate coasts - sheltered estuarine beaches For beaches that are typically sheltered from waves, erosion can be dramatic + recovery a very slow pace Sandy Beaches + Soft Sediment - Environmental Impacts - Pressures on associated sediment infauna - Sources of contamination: stormwater drains → industrial waste + raw sewage - Climate change - Major environmental impacts for beachers incl. erosion by storms which also can strand masses of seaweed + animals + plastic pollution → storm surge - beach erosion - Recreational fishing - Cars driving on beaches Soft bottom habitats - Muddy + sandy habitats support diverse species - These incl. species that: - Live on the sediment e.g. fishes, prawns, crabs, + sea stars - Live on semi buried such as rays - Live in buried in the sediment e.g. worms + claims + heart urchins - Sediment can have massive populations of very tiny animals called meiofauna - Full range of feeding regimes → deposit feeders, filter feeders, scavengers + predators - Soft sediment = \^ biodiversity + bioturbators Environmental concerns - These habitats can be very productive habitats for fishing → both invertebrates → prone to overfishing - Impacted by land run off - Dredging for port development + maintaining shipping routes Sediment contamination - Effect on sediment biodiversity - Measurement of environmental impacts on soft sediment fauna → traditionally done by collecting samples of sediment by grabs or cores then extracting the biota + identifying the organisms - Environmental monitoring using sediment samples = expensive + time consuming - Monitoring assemblages in marine habitats w/ artificial units → assess environmental impacts more efficiently + cost-effective approach **MARINE HABITATS -- ROCKY SHORES** Rocky shores - Are large environmental gradients over small distance → marine to terrestrial in a short distance - Exposure depends on elevation of the shore → rock platforms, cliffs, + boulder fields - Exposure gradient from low to high shore → tide, aerial exposure + temp, oxygen - These exposure gradients as well as the substratum type strongly influence the animals that occur on rocky shores + where they are found on the shore - Are home to a diversity of species - Grazing species: snails, limpets, sea urchins, chitons - Predators: anemones, whelks - Suspension feeders: barnacles, oysters, ascidians - Algae: Neptune's necklace, microalgae - Food for birds such as oyster catchers at low tide + fishes at high tide - Littoral zone: from high water mark to submerged zone + so includes the intertidal Environmental gradients - physical factors: Most important are: - Tides → vertical - Wave exposure → horizontal Tides: effect of moon's gravitational force - 2 tides in Sydney → but this varies across locations around the world - 24hr 50min cycle Wave action - Strong gradients from exposed to sheltered shores - Important agent of disturbance - Interacts with tides + temp Other variable factors - Abiotic - Temp - Light - Salinity - Oxygen levels - pH - Substratum (rock type, surface topography, rock pools) - Physical factors - Desiccation stress - Disturbance - Biological processes - Competition - Predation - Herbivory - Succession - Natural + human-affected processes Rocky shores as one of the most intensely studied marine habitats - Comparatively easy access (does not require SCUBA) - Ease of experimental manipulation → to address hypotheses on ecological patterns and processes Many studies on - Competition - Predation (predator prey interaction) - Supply side ecology (dynamics of recruitment - through larval supply) Manipulative experiments - Necessary to determine which physical + biological processes determine the distribution + abundance of marine organisms - Studies from intertidal rocky shores have been very influential in marine ecology + ecology in general - Herbivory: many grazer exclusion experiments Models for marine ecology - Ease of data collection + experimental manipulation - Interactions between grazers such as limpets + algae + the predator prey relationship between whelks + barnacles has been a focus Ecologically important species - Differs between shores, exposure gradients - Resident species differ w/ respect to the type of shore (e.g. sheltered/exposed) + where in the world - Diff guilds - Grazers: herbivores that eat algal films, scrape algae off the rocks, e.g. limpets, snails, sea urchins, with habitat on shore influenced by adaptations to aerial exposure (rock surface/crevice vs tide pool species) - Predators: fishes (high tide), birds (low tide), predatory snails, anemones - Filter feeders: barnacles, tube worms - Local keystone predator on Sydney rocky shores - No generalist predator in AUS shores comparable to *Pisaster* in NA - No sessile species that dominate space like *Mytilus* - Sea stars are very abundant intertidal predators Zonation - Zonation in animal distributions is evident from low→high on the shore - Changes in the pattern of abundance + species composition w/ height on the shore - Each zone is characterised by indicator organisms although there is patchiness in the pattern due to diffs between shores - The distribution of species is influenced by tide height + splash from waves + the presence of shade + structures such as tide pods - Diversity is highest lower on the shore as a visit on a good low tide shows Environmental impacts of rocky shores - Heatwaves can cause mass mortality of intertidal animals especially if they coincide w/ big low tide series - This has been well documented for \100yrs but is now being exacerbated by climate change - \^ in intensity of flooding + storms - Harvesting by humans is a big issue - In SYD ppl collect buckets of urchins, limpets, abalone, + turban shells for consumption - The intertidal ascidian is used as fishing bait - Trampling by humans is also an impact Temperate rocky reefs + seaweed beds - Temperate reef systems are characterised by rocky reefs of large macroalgae (seaweeds) - These are massively productive plants that are the engineers of temperate waters, providing habitat + sources of nutrients → a massive food base for a vast diversity of species - Important in the carbon cycle + storage of 'blue carbon' - These macroalgal-based ecosystems support an abundance of herbivorous species e.g. amphipods which in turn are a key source of food for predatory fishes - There are also many herbivorous fishes that eat kelp - Kelp beds support many herbivores - The rocky reef infrastructure supports a great diversity of species, which often live around the stripes (roots) of kelp - Ecologically + economically important predators incl. lobsters + fishes Temperate latitudes - Seaweed communities form a major habitat in cold water - Seaweeds have low tolerance for \^ temps - Massive die offs of kelp occurs during heatwaves - The continued \^ in temps due to climate change is a concern for their survival Large seaweeds - Macroalgae kelp that form the foundation of underwater forests - The herbivore guild is ecologically important especially for invertebrates - Also a few species of herbivorous species Environmental impacts - Storms and warming waters destroy kelp - Invasion of tropical fishes + success of heat tolerant macroalgae The nature of habitats in temperate rocky reefs - There is a diversity of grazers that classify as habitat determiners → molluscs + echinoderms → sometimes called habitat engineers NSW has 2 species of barrens forming sea urchins \*Centrostephanus rodgersii\* - Distribution from subtropical to temperate region - Exhibits long term population stability - with \^s in the south - In subtropical NSW occurs w/ coral - The EAC has moved \~400km further south since the 1960s resulting in an input of C. rodgersii larvae + recruitment - Stronger EAC = \^ larval dispersal south - Warmer water = more favourable temps for larval development + recruit to adult pops - Impact of sea urchins shifting south to TAS: - Sea urchins are a fishery resource aka 'uni' - TAS development of a sea urchin fishery as a management tool to address the 'Centro problem' - In TAS culling (removal) programs are currently underway - There are many species that depend on barrens habitat bc *C. rodgersii* contributes to creation of mosaic = patchy habitat types → habitat mosaics matter **MARINE HABITATS -- SEAGRASS** 1\. Know the definition of seagrass 2\. Appreciate the ecological importance of seagrass habitat 3\. Know the ecological services provided by oyster reefs 4\. Appreciate current marine restoration activities through several case studies 5\. Understand the influence of climate in eastern Australia and concept of "Species on the Move" Seagrasses Flowering plants of terrestrial origin that returned to the sea + are fully adapted to live underwater In NSW + AUS There are only 60 species of seagrass worldwide + SA is the global centre of seagrass diversity w/ \~20 species \~14 of which occur nowhere else Diversity + Function - Seagrass beds occur in protected estuaries + bays - They are highly productive habitats producing a vast amount or plant material + form a major source of nutrients. They are among the most productive ecosystems on Earth - A highly valuable habitat that increases plant production + greatly expands the base of the food chain - Key spill over effects of export of nutrients to non-vegetated areas (e.g. seagrass detritus) - Seagrasses root systems penetrate + stabilise soft substrates + are important in coastal protection - Improve water quality - Carbon cycle: bury about 12% of the total carbon storage in marine ecosystems → storage of 'blue carbon' - Seagrass is a key food source for endangered herbivores (turtles + dugongs) Seagrass beds - Important habitat providing food + refuge for many species - Provide nursery area shelter for juvenile stages of fishes including many commercially important ones - Crucial habitat for endangered species - Leaf decay is a major of detritus → the detritus + the microbiome that colonises dead leaves is highly nutritious for many invertebrates - Fishes prey on the animals in the bed - Epiphytic algae that colonise the surface of seagrass leaves is an important source of food for many invertebrates Biodiversity + function - Food, habitat, refuge, nursery - Among the most productive ecosystems on Earth - Water quality + sediment stabilisation - Coastal protection Loss of seagrass Causes: - Coastal development - Degraded water quality - Climate change Environmental concerns + restoration - Need clear water for photosynthesis - Eutrophication, sedimentation, sewage release can kill seagrass beds → degrading of harbour - Mass swathes of seagrass beds have been lost due to urban development, shipping, anchoring → to the detriment of local ecosystems Oyster reefs - Oysters feed by filtering water + collecting little organisms + organic matter floating in the water column - Oyster can clean the water of pollutants + other nasties in the water column, maintaining ecosystem health - They filter large quantities of water through their gills → improving water clarity + quality - Loss of 90% of oyster reefs loss across the world - Caused by: - Harvesting live oysters for food - Harvesting oyster shells for lime - Water quality decreases - Disease - Invasive species - AUS loss directly related to colonisation + mortar - Loss of ecosystem services - Wave attenuation - Sediment stabilisation - Provision of habitat - Provision of food - Water filtration Restoration - Restoration is a big field in marine ecology + conservation → rewilding marine ecosystems - Restoring key ecosystem services - Restoring blue carbon Restoration of oyster reefs - Oyster reefs are layers of concreted oysters laid down over time which serve as naturally engineered habitat supporting a diversity of species + boost fisheries - They play a major service in improving water quality by their suspension feeding activity + in shoreline protection - AUS's oyster reefs - The remnant SYD rock oyster reefs in NSW are being investigated + application of artificial reefs is being trialled Sydney's lost reefs from: - Water filtering - Provides habitat - Protect shoreline infrastructure - Boost fisheries Restoration of crayweed - This disappeared from 70km of the Sydney coast → likely due to pollution - Operation Crayweed has successfully transplanted this species into Sydney + they have reproduced Ecological restoration of urban marine habitats - Urban marine habitats: - The presence of artificial infrastructure - Close to city waterfronts with high-population densities - Sydney harbour: modifications create human built habitats that differ greatly from natural system - The intro of natural processes + functions in the design of low-impact, multifunctional, bio-enhanced artificial structures for the built ocean environment Climate change - Climate change is altering coastal + oceanic conditions - Problems due to greenhouse gas (CO2) emissions - co-occurring stressors: 1. Global warming (air & ocean) 2. Ocean acidification - AUS → warming of air + ocean 1. Increasing temp: coastal waters 2. More extreme events: floods, cyclones, heatwaves 3. Altered ocean circulation + species distribution: tropicalisation of temperate AUS - Ocean acidification 1. Decreases ocean pH: problems - direct corrosive effects, interfere w/ pH dependent processes (e.g. enzyme systems) 2. \^ body levels of CO2: hypercapnia - physiological stress 3. Decreased carbonate mineral saturation: lower availability of the building blocks to make a skeletons + shells - Warming + acidification of AUS coastal waters - NSW estuaries are rapidly warming, acidifying + refreshing - Fauna is also changing due to heatwaves → mortality + increasing incidence of disease Species on the move - A universal response to climate change is the shift in distribution of species towards the poles → this had been going on for decades, but scientific records are scarce - When scientific records are scarce detecting change depended on museum records + fishing data - In AUS there is now very clear evidence for shifts in the distributions of seaweeds, fishes, invertebrates - These shifts can have severe ecological impacts - phase shifts - Problems of ecological mismatches - Problems due to changes in phenology Case study - impact of climate change range extending urchins on kelp habitat - The EAC is \^ in southward flow, more warm tropical water in SE AUS + associated spread of warm water species - Temperate AUS: fauna is changing + invasion of tropical species to NSW - Connectivity: larvae on the move - Habitat phase shift over 40 yrs - Stronger EAC = \^ larval dispersal south - Warmer water = more favourable temp for larval development + recruit to adult pops Tropicalisation of temperate AUS - Invasion of tropical + subtropical species to NSW such as herbivorous fishes + corals - Fauna is changing but not all species are moving - Species on the move, tropicalisation of temperate regions + temperate species from mainland extending to Tasmania **MARINE HABITATS -- CORAL REEFS** 1\. Know what coral reefs are 2\. Know the environmental conditions required for coral reefs to become established 3\. Appreciate the ecological importance of coral reef habitat 4\. Know the ecological services provided by coral reefs 5\. Understand the impact of ocean warming and marine heatwaves on corals and their bleaching response Coral reefs - Coral reefs are geomorphologic structures formed by accretion and accumulation of aragonite, produced primarily (but not exclusively) by hermatypic corals (= corals that host symbiotic algae called zooxanthellae) - Are the largest geological structures built by organisms: species from microbes to animals calcify making rocks out of water - Major calcifiers: corals, coralline algae + a host of other calcifying species (e.g. molluscs, sponges, bacteria, etc.) - Grow to sea level which is the upper limit of their habitat, and low tide is their constraint → sea level rise is a concern = drowned reefs Distribution - Found in the tropics - Are mostly confined close to the equator - Depth: reef building corals, shallow water - Reef building corals have symbiotic photosynthetic algae called zooxanthellae - depth restriction due to light penetration Conditions for survival Corals are ecosystem engineers, constructing the habitat required by 1000s of species → corals can only form reefs, grow + thrive in the presence of specific environmental conditions - Temperature: \~18degC generally required but thermal stress kills coral bleaching + death - Clear water: light is essential for a functional symbiosis depending on photosynthesis turbidity, sediment loads, pollution → kills coral - Salinity: \~35ppm - corals do not like freshwater, which is usually associated w/ excess nutrients from land run off → freshwater (decreased salinity) kills reefs - Aragonite saturation: building blocks of coral skeleton ocean acidification is a serious threat - Current: connectivity important in ability for larvae to travel between reefs → recruitment + recovery Conservation value - Most diverse marine ecosystems - Species list at vulnerable or endangered - Coral reefs are susceptible to disturbance Coral diversity Types of corals - Hermatypic: produce CaCO3 skeleton - Ahermatypic: no CaCO3 skeleton - Reef building corals are known a scleractinian corals + categorised as phylum Cnidaria, class Anthozoa, subclass Zoantharia, order Scleractinia Coral anatomy - Polyp is the unit, w/ tentacles + stinging nematocysts - Converge at mouth which passes to gut - Colony shares systems - Connective - Digestive - Build CaCO3 skeleton beneath - A thin veneer of tissue sits on top of the skeleton How coral reefs work - Tropical surface waters are clear + depleted of nutrients - Animal-algae symbiosis supports the great biomass on coral reefs - Symbiosis powers coral reefs = the basis of the ecosystem - Low plant biomass (but \^ productivity) - Extremely efficient mechanisms of nutrient re-cycling - Many species have symbiotic algal cells in their tissues, e.g. zooxanthellae in corals Coral symbiosis - Zooxanthellae → algal endosymbionts - Photosynthesise - Organic matter passed to host coral - Corals typically feed as well (zooplankton or detritus) - Tentacles - Mucus sheets on surface - Mesenterial filaments - Absorbing DOM - Necessary for reef building - Zoox also found in other animals, e.g. anemones, nudibranchs, clams, etc. Reef building - Corals + Coralline algae - Major depositors of CaCO3 - Buffer from wave activity - Trap sediment - Reef is cemented by: - Sponges - Bryozoans - Coralline algae Great Barrier Reef - Can be seen from space - The largest geological structures built by organisms Conservation - The GBR is crucial from a conservation perspective - This marine park + world heritage area supports populations of species that are listed by the IUCN as Vulnerable + Endangered (e.g. dugongs, turtles, etc.) Coral reef development - Fringing reef: well-developed reefs attached to mainland or continental islands - Platform or lagoon reefs: reefers begin by growing toward the surface of the ocean, eventually spreading out laterally → in many cases, wave action hollows the interior + a lagoon forms Threats to GBR - Downstream effects of land use (water quality issues) - Coral bleaching, rising temps - Coastal developments - \^ fishing effort + impacts - Shipping + pollution incidents - \^ tourism + recreation - Port development Long term future - Global climate change - Decrease in coral cover + mortality post bleaching - \^ cyclones/storm activity + intensity Oceanography and connectivity - Influences of tide, longshore currents (e.g. EAC), + wind - On physical structure + larval trajectories Coral spawning - Vast majority of corals are broadcast spawners - Fertilisation depends on synchronous breeding + gamete recognition Coral reef connectivity - Currents: connectivity between reefs sufficient larval supply, fishes + invertebrates - Oceanographic scale: EAC, wind, tides, upwellng - Mesoscale (1000km) - Reef scale → local topography Coral reefs provide vast ecosystem services - Supports a vast biodiversity - Food security for millions of people - Protection from coastal erosion and storms - Accretion against sea level rise - Most recreational services of any ecosystem → bass of tourism + regional economic prosperity Threats to coral reefs Main threats - Overfishing - Pollution - Boat traffic - Dredging - Climate change - Increasing ocean temperature - Ocean acidification from global warming as \^ CO2 uptake decreases seawater pH - Changing circulation - Increasing storm frequency + intensity - More extreme run-off (rainfall) events) - Sea level rise Limitations to coral growth nutrient concentration - Corals need nutrients but at high concentrations they can be outcompeted by algae (overgrowth occurs) - Eutrophication a treat to reefs → in shore reefs disappear or grow poorly for this reason Limitations to coral growth - temperature - Global warming + marine heatwaves are the major contemporary threats to reefs - Growth related to temp - Too cold (\~20degC) or warm (30-35decC) - Lose zooxanthellae - If not re-acquire, die Coral bleaching - Symbiotic algal cells (zooxanthellae) that provide food for corals are expelled - During bleaching, as the symbiotic algae are discarded, leaving the polyp behind - After bleaching the coral may 1. Recover slowly by re-acquiring its symbiont friends 2. Die, having run out of energy in the absence of the symbiotic algae that provide it with carbohydrates Degradation from reef to rubble - Degradation is declines in: - Coral cover - Habitat complexity - Species diversity - Key indicator species - Increases in: - Macroalgae - Bioerosion **CONSERVATION SCIENCE** Conservation biology - The applied ecology of endangered species - The science concerned w/ increasing the probability that the Earth's species will persist - The scientific study of Earth's biodiversity w/ the aim of protecting species from excessive rates of extinction Applied ecology Ecology of human disturbance - Use of ecological theory + principles to explain + manage human impacts - Effect of pollution - Effect of invasive species - Effect of land clearing - Managing harvestable species Ecology in conservation - Conservation biology built on ecology - Reasons for species rarity + decline are ecological q's - Legal protection mechanisms built on ecology, e.g. NSW Threatened Species Act Mammal Extinction in AUS - AUS has lost 18 species in last 200 yrs - Non-flying mammals in the Critical Weight Range have suffered most - Most had disappeared by the 1930s Declined populations of animals - Western species - Grassland + woodland fauna - Ground dwellers - Small sized The ICUN red list categories - International Union for the Conservation of Nature - 1.8mil species described in total - 22% mammas, 32% amphibians, 14% birds, 32% gymnosperms are threatened - Things are generally getting worse in the world → global patterns of net change overall extinction risk - So many species are data deficient → particularly invertebrates Diversity - Genetic diversity: conserving genetic potential for resilience - Community diversity: unique conservation unit, listed in places Reasons for conservation - Non-use values - Intrinsic value: rights of species to exist - Existence value: knowing it exists - Use value - Direct consumptive (food) or non consumptive (aesthetics + cultural) - Indirect (ecosystem services) - Options + bequests: potential uses in the future History of Conservation Early conservationists - Game conservation in the Bible Short history of western conservation ethics - Romantic-Transcendental Preservation Ethic: - John Muir 1838-1914 - Being in nature brings you to closer to God - Resource Conservation Ethic - Gifford Pinchot 1865-1946 - Nature is full of natural resources to exploit - Evolutionary-Ecological Land Ethic - Aldo Leopold 1886-1948 - Species do things in ecosystems = intrinsic value Conservation Paradigms Small vs declining populations - Small populations are at risk simply bc they are small - Declining populations are at risk of being driven to extinction Species vs ecosystems - Controversy between focusing on threatened species or conserving the whole ecosystem Components of biological systems - Biosphere, ecosystems, communities, species, populations, individual organisms, organs, tissues, cells/molecules Conservation vs restoration - Prevention vs cure - Preservation vs exploitation + recovery - Bio banking: debates on whether it works w/ imperfect knowledge Defining conservation - Conservation biology is a crisis discipline - Tolerating uncertainty is often necessary - Conservation biology is a mix of science + art requiring intuition as well as info - Conservation is synthetic, electric + multi-disciplinary w/ dependence on biological + social science disciplines - Conservation biology is holistic: reductionism alone cannot lead to explanation of community + ecosystem processes Central postulates - Functional postulates - Many species constituting natural communities are products of co-evolutionary processes - Many ecological processes have thresholds → can go discontinuous, chaotic or suspended - Genetic + demographic processes have thresholds below which random forces begin to prevail - Nature reserves are inherently disequilibrial for large, rare organisms - Normative postulates - Diversity of organisms is good - Ecological complexity is good - Evolution is good - Biotic diversity has intrinsic value **MANAGING SMALL POPULATIONS** \- Understand demographic drivers of change \- Understand demographic threats to small populations Allee effects Viable population issues \- Understanding how these are used in practice Population Defining population A group of interbreeding individuals (organisms) of the same species occupying a particular space at a particular time Population change influences - Births - Deaths - Immigration - Emigration Equation of rate of increase *r* r = (b-d) + (i-e) - R~m~ = intrinsic rate of increase - The rate of increase multiplied by how many there are along - How close the population is to the carrying capacity → population close to the carrying capacity does not \^ much bc the environment can only support that many - If long way from carrying capacity, the value is low → the population will be \^ at its max rate Allee effects - An Allee effect is a positive association between absolute avg individual fitness + population size over some finite interval - Strong Allee effect = -ve population growth at a small population size - When population size is small, rather than reduced competition, there are less food opportunities resulting in an even lower population size Mate incompatibility - Not all adults contribute to the next generation → e.g. immature, over aged, bad mothers, etc. - Not all breeders contribute equally → big variance = high skew of future gene pool - Effective population size equation: - Where σ^2^ is the variation in family size among females Sex ratio effects + N~e~ - Sex ratio skew reduces effective population \$N~e~=4N~m~N~f~/(N~m~+N~f~ ) - Depends on mating system - In a polygamous mating system, things are stable (50/50) - Skew of too many males and/or females, the effective population size drops down, sometimes dramatically Minimum viable population - Size of population needed for \ - Legal req. to fully restore - Challenges incl.: understanding what is taken may not come back + restoring flora (habitat) may not result in the ecosystem health returning Co-extinction General - Loss of obligate dependent species - Parasites after hosts - Plants after pollinators - Predators after prey - Specialised behaviours - Poorly studied process - Few studied e.g.s - Some been overturned - Is an under-recognised threat Coextinction of mealybug \*Pseudococcus markvarheyi\* - Sap feeding bug obligate on *Banksia montana* - *B. montana* undergone major decline due to fire, dieback disease + clearing - Too few plants too isolated to support bug now extinct - Big problem - Tracking vertebrate extinction is already difficult → parasite ecology is poorly known - 6600 affiliate species at risk → co-endangerment **CLIMATE CHANGE & EXTINCTION SYNERGIES** Climate Change Predictions - Global warming: temperatures are increasing at an unnatural rate every year → anthropogenic - In the short term, can't observe much change, but long term it is going to get even warmer + wetter + evapotranspiration → amt of change vary depends on the landscape, some places will not change that much - Already hot places will likely get even hotter - Sea temps are rising as well + getting more acidic - Results in bleaching effects on coral reaching thermal maximum = death of animals which maintain coral - CO3 being lost to corals - CO2 altering calcification of larvae → have flow on effects on the adult - Changes in food webs w/ higher sea temps = lower overall biomass bc of decrease in phytoplankton - Complex trophic implications - Sea levels rising → glaciers are melting + evapotranspiration is occurring more frequently - Predictions, however, may not be accurate, though we do know that landscapes are going to change - More extreme weather events Implications for individual species - \^ atmospheric CO2 concentration → climate change → effects on physiology + phenology + distributions → changes in species interactions → further shifts in distribution + extinction of some species → changes in community structure + composition - Future climate change leads to the vulnerability of endemic island mammals The big issue - The rate of change is most concerning → the time frame in which things are changing now, the environment + organisms cannot keep up w/ - Concerns that extreme changes in environments = more suitable for invasive species - AUS tropical rainforests can adapt to change, but not at the rate that it is occurring → extreme environments will change the most - Change is not just in an individual organism, but changes in the interactions bc of how it changes the fundamental aspects of their biology Options for species - Evasion (relocation) - Assisted translocation → may not work as natives may become Aliens, risking extinction of other organisms - In-situ change (phenotypic plasticity) - Phenological change may matter for some species - Genetic change - Future proofing reserves Adaptation by relocation → challenges for AUS wildlife - AUS has hard limits of altitude - 13% \500m - 0.01% \> 2000m - AUS is flat → can't easily go uphill - AUS is fragmented → dispersal options few + rivers run east west Mechanics of Synergistic Effects The idea that something creates CO2 in the atmosphere can actually be fed by the consequences of \^ CO2 in the atmosphere (positive feedback) - E.g. climate change: conditions get hotter + drier → \^ fire → more CO2 gets released as things are burnt → more climate change effects - Many extinction forces are not happening in isolation w/ one another, but they are all interacting w/ one another Conclusions - Predictions of climate change impact on biodiversity are dire - Phenological mismatches - Physiological mismatches - Extreme events exacerbate mismatch - Strategies more mitigation are limited + fraught - Adaptations likely too slow to address mismatch **CONSERVATION FUTURES** Bold new directions for conservation De-extinction - Defining extinction - Extinction is the end of an organism or of a group of organisms (taxon), normally a species - The moment of extinction is generally considered to be the death of the last individual of the species - Extinction matters - 1000 rangers killed in 10 yrs when protecting endangered animals - AUS has acute extinction guilt → 50000 yrs of history - Legislation acts to prevent extinction + biodiversity loss - Revive + restore program - Bringing back extinct species - When extinctions happen, many occur at the hands of humans → humans are responsible - De-extinction offering hope that conservation biology needs - Conservation biology is a crisis discipline → but we're habituating to bad news stories - Possibly the ultimate solution to extinction risk - Considerations for the resurrection of extinct species - Where they will live - Will there be enough genetic diversity - Welfare issues - Co-extinction issues - Ecosystem issues - Who chooses what to resurrect - Hypotheticals - What is conservation if there is no extinction - Choosing what species to bring back - The extinction of extinction - If 1 species is resurrected, extinction as a concept will disappear - What's done cannot be undone → sometimes the ultimate damage can be undone - What will conservation biology lose if extinction is extinguished - Not arguing pessimism over optimism - Don't need more extinctions - Need thresholds for ecological impact - W/o extinction risk conservation has no voice Rewilding - Rewilding to restore an ecological balance - Different to reintroducing → returning not just species in a reintroduction, but function - Need big herbivores to control vegetation, need predators to control prey numbers, etc. - Goal of rewilding is to reinstate lost processes by reintroducing species that may not necessarily have evolved there, with things that might do the right thing - Hypotheticals - Putting wildness where they can provide an ecosystem service - Rewilding gaining momentum Novel Ecosystems - Defining novel ecosystems - Novel ecosystems are human-altered environments w/ unique combinations of species and conditions that differ from historical ecosystems and often cannot be reversed. - A lot of the world is impact by human presence, having changed things an awful lot → how much human involvement is ok? - Seeing which ecosystems that are untouched by humans - Invaders changing ecosystems - Choosing what to conserve - Perhaps give up → too many people occupying space + not possible to conserve - Hypotheticals - Choosing how to manage conserved areas Conservation triage - Can we save every species? - The process of prioritizing limited conservation resources to protect species or ecosystems with the highest chances of survival or greatest ecological significance, acknowledging that some may not be saved due to resource constraints. - Not enough resources to spend on all of the taxa that are in need - Smart decision making in actions - Not enough money to spend on every species - Plan to use conservation triage to create high priority (55%) and lower priority (45%) species - Almost like a popularity contest - Conservation is comparatively cheap - Tell the public to allow more conservation work to be done - Hypotheticals - Very controversial subject - Don't tell people that things need help = low funding/interest/research Offsetting conservation impacts - Threatened communities central to conservation - If people want to destroy habitat, legislation states that you need to protect the same area or areas of the same/more value, in order to offset the damage that is being done - Loss of land + habitat meant that the same conservation value of this loss needs to be protected in perpetuity for longer - Biobanking: impact now- conserve later - Providing the funds to be able to create + recreate habitats/vegetation that were lost - The Biodiversity Offsets Scheme is the framework for offsetting unavoidable impacts on biodiversity from development w/ biodiversity gains through landholder stewardship agreements - Lesson from restoration ecology - Challenge to in-situ conservation - Can't replace what's lost - Goals posts shifted - Novel ecosystems - Conciliation biology - Are we giving up