Forest Biodiversity Lecture Notes PDF

Forest Biodiversity Lecture 1: Introduction to Biodiversity  What is Biodiversity? Biological Diversity - coined in 1980 by a conservation biologist (Thomas Lovejoy) Biodiversity - coined by W.G. Rosen in 1985, then first appeared in publication in 1988 by E.O. Wilson ...

Forest Biodiversity Lecture 1: Introduction to Biodiversity  What is Biodiversity? Biological Diversity - coined in 1980 by a conservation biologist (Thomas Lovejoy) Biodiversity - coined by W.G. Rosen in 1985, then first appeared in publication in 1988 by E.O. Wilson  BIODIVERSITY is… the variety of life in all its forms varia,on of life at all levels of biological organiza3on - genes ➡ species ➡ ecosystems and the valuable func5ons they perform essen3ally a synonym of `Life on Earth’ Levels of Biological Organization LEVELS OF BIODIVERSITY DIVERSITY ECOSYSTEM LEVELS OF BIODIVERSITY SPECIES DIVERSITY  Species diversity In 2022, based on IUCN Redlist, an estimated 2.16 million species have been described; estimates for the total number of species existing on earth at present vary from five million to nearly 100 million. A conservative working estimate suggests there might be around 12.5 million. LEVELS OF BIODIVERSITY GENETIC DIVERSITY  Genetic diversity Genetic diversity is the sum total of the genes in each organism that inhabit the earth. The gene, as a factor of heredity is passed on from parent to offspring and determines the physical characteristics that will be expressed in every generation. The gene is a storage facility, a repository of genetic information. GENETIC DIVERSITY GENETIC DIVERSITY  Species - the basic unit of classification for organisms; include closely related, morphologically similar, interbreeding, individual organisms Species diversity Nepenthes sp. can be assessed at different levels Nepenthes merrilliana of the classification hierarchy, viz. species, genera, families. Species diversity refers to the variety of different species, or the diversity between species. Nepenthes alata Nepenthes truncata What is a Species? The “biological species concept” (Ernst Mayr, 1940): “A species is a group of actually or poten?ally interbreeding natural popula?ons that are reproduc?vely isolated from other such groups” the basic unit of classifica?on What really is a species?  How many species are there? In 1700’s, time of Linnaeus – only about 4,200 plants and animals were described Today – about 2.16 million species (15.4% only) Global estimates – 12 to 14 million species (WCMC 1992, Cox 1997) to as high as 30 million (Hammond 1992, Ehrlich & Wilson 1993) Insects – the most diverse organism SPECIES DIVERSITY  Species richness in major groups of SPECIES DIVERSITY Chordates Plants 286,000/320,000 organisms Bacteria Bacteria Vi V ru iru s e se s s Fungi 70,000/1.6 Fungi M 70,000/1.6 M Nematodes Nematodes Arachnids Arachnids ‘Algae’ Insects 40,000/ 350,000 Insects The Living Estimated total: Purvis, A. & A. Hector. World 14 million species 2000. Nature 405: 212-219.  Biodiversity Crisis Documenting what is here before it is gone. Langgam, Sumatra, Indonesia www.maanystavat.fi  CURRENT STATE OF PHILIPPINE FORESTS World's 10 Most Threatened Forest Hotspots Remaining% Predominant%Vegetation% Rank% Hotspot% Forest% Type% Tropical,"Subtropical"moist" 1" Indo'Burma"(Asia'Pacific)" 5%" broadleaf"forests" Tropical,"Subtropical"moist" 2" New"Caledonia"(Asia'Pacific)" 5%" broadleaf"forests" Tropical,"Subtropical"moist" 3" Sundaland"(Asia'Pacific)" 7%" broadleaf"forests" Tropical,"Subtropical"moist" 4" Philippines"(Asia'Pacific)" 7%" broadleaf"forests" Atlantic"Forest"(South" Tropical,"Subtropical"moist" 5" 8%" America)" broadleaf"forests" Mountains"of"Soutwest"China" 6" 8%" Temperate"coniferous"forests" (Asia'Pacific)"" California"Floristic"Province" Tropical,"Subtropical"dry" 7" 10%" (North"America)" broadleaf"forests" Coastal"Forests"of"Eastern" Tropical,"Subtropical"moist" 8" 10%" Africa"(Africa)" broadleaf"forests" Madagascar"and"Indian"Ocean" Tropical,"Subtropical"moist" 9" 10%" Islands"(Africa)" broadleaf"forests" Tropical,"Subtropical"moist" 10" Eastern"Afromontane"(Africa)" 11%" broadleaf"forests;"Montane" grasslands"and"Shrublands" " 24 Source: Conservation International 2011 Forest Biodiversity Lecture 2: Philippine Biodiversity These countries has less than 10% of the global surface, but support more than 70% of the biological diversity on earth.  PHILIPPINE FAUNAL DIVERSITY 111 species of AMPHIBIANS… …82 species are FOUND ONLY in the Philippines.  REPTILES About 270 species of Reptiles (lizards, turtles, crocodiles, and snakes) are found in the country. …with 208 sp. (82%) endemic to the Philippines Only about 20 species of snakes are venomous. Two species of crocodiles Saltwater crocodile Freshwater crocodile BIRDS 192 We of have these moreoccur thanonly 576 inspecies the Philippines. of birds  MAMMALS Of the 179 species of land mammals, 52 threatened species, 1 possible extinct 111 species are found only in the Philippines. INSECTS More than 20,940 species 69.8% are endemics Total number of wildlife fauna species in the Philippines No. of Endemic Threatened Major Taxa Species Species Species Amphibians 105+ 82+ (78%) 24 (24) Reptiles 254+ 208+ (82%) 8 ( 4) Birds 576+* 192+ (33%) 74 (59) Mammals 202+** 110+ (54%) 51 (41) Total 1137+ 592+ (52%) 157 (128) + includes new species (38 for amphibians, 35 for reptiles, 15 for mammals) * includes rediscovered species ** 22 species of dolphins, whales and dugong  Vertebrate diversity and endemism of some megadiversity countries Country Amphibians Reptiles Birds Mammals Land Area (sq. km.) Brazil 517 (294) 468 (172) 1622 (>191) 524 (131) 8,511,965 Indonesia 270 (100) 511 (150) 1531 (397) 515 (201) 1,916,600 Colombia 583 (367) 520 (97) 1815 (>142) 456 (28) 1,141,748 Mexico 284 (169) 717 (368) 1050 (125) 450 (140) 1,972,544 Australia 196 (169) 755 (616) 751 (355) 282 (210) 7,686,810 Madagascar 178 (176) 300 (274) 253 (103) 105 (77) 587,045 China 274 (175) 387 (133) 1244 (99) 499 (77) 9,561,000 Philippines 83 (58) 254 (168) 556 (177) 179 (111) 300,780 Numbers in parenthesis are endemic species * based on Alcala and Brown (1998), Gonzalez (unpub.), Dickinson et al. (1991) and Heaney et al. (1998)  Top 10 countries in the world for bird endemism Country Endemic % Endemism Species Indonesia 397 26% Australia 355 47% 1st Brazil >191 12% Philippines 177 32% 3rd Colombia >142 8% Mexico 125 12% Peru 109 6% Madagascar 103 41% 2nd China 99 8% PNG 85 11% * based on Alcala and Brown (1998), Gonzalez (unpub.), Dickinson et al. (1991) and Heaney et al. (1998)  Corals 12 species are endemic to the Philippines & Indonesia 20 species recently described in the Calamianes 1 new species of Leptoseris in the Kalayaan Is. 22,000 species freshwater, land and marine molluscs Reef Fish  2500 species  915 species reef and reef-associated fish PLANTS estimated 15,000 species, 50% are endemics 70 – 80% Flowering plants 984 Threatened species  BIODIVERSITY HOTSPOT Ø Philipine species face one of the highest level of endangerment Ø >93% of forest cover has been lost in the last 500 years ago Ø 697 threatened species (2010 IUCN Red List) Ø megadiversity and biodiversity hotspot country Ø 2nd hottest spot 21 Forest Biodiversity Lecture 3: Patterns and Theories of Species Diversity  Questions 1. What are the reasons the tropics have more species than temperate and polar regions? 2. What does it mean that biodiversity patterns are scale dependent ? 3. How do we estimate the total number of world s species? 4. What are the reasons species richness goes up when you sample a larger area? How many species are there? How do we know? Take what we do know, project it to include things we don t Example 1: species-area curves Example 2: body size Example 3: sub-sampling  How many species are there? Estimates range from 5 to 100 million species (1.7 million described) New species being discovered Strong biases in counts – 1980: study of 19 trees in a tropical rainforest 1200 species of beetles 80% previously undescribed Likely 6 to 9 million species of arthropods – 1 sq m tropical forest: 200,000 mites, 32 million nematodes, 90 million bacteria # of species? – Oceans: very poorly studied, especially deep sea Estimated 1 million undescribed species from deep sea Scale dependence Biodiversity patterns are sensitive to SCALE. Just as what you see through a telescope depends on the magnification and field of view. Three basic reasons species richness increases with area: 1. Habitat diversity goes up (a greater range of environments are sampled, potentially including a greater array of niches) 2. Population sizes increase, leading to a lower extinction rate (from island biogeography) 3. Some species require large areas because they have large ranges or habitat requirements (e.g., large predators) Patterns of species richness Broad scale: Latitude Climate Elevation Fine scale: Productivity Disturbance Global plant diversity at large scales  An example of a typical latitudinal gradient New World Bats 180 160 140 Number of species 120 100 80 60 40 20 0 -80 -60 -40 -20 0 20 40 60 80 Data from Lyons & Willig 1997 Latitude  Another example, Palms of the New World 160 140 Number of Species 120 100 80 60 40 20 0 -40 -30 -20 -10 0 10 20 30 40 Latitude  Latitudinal Gradient Groups that provide evidence for a latitudinal gradient in diversity: Birds Marine Gastropods Mammals Marine Bivalves Freshwater Fishes Marine Fishes Trees Corals Epiphytes Insects Many have argued that this pattern is universally true for all large taxonomic groups Many small taxonomic groups, e.g. pine trees, don t show the expected pattern despite the fact that trees overall show the latitudinal gradient Pinaceae of North America 50 40 Tree species: Number of Species 30 U.S. and Canada ca. 679 20 Costa Rica 10 1400+ 0 0 10 20 30 40 50 60 70 80 Latitude (5 degree bands)  Latitudinal Gradient Other taxonomic groups also don t show the expected latitudinal gradient in diversity, but in each case the expected pattern is seen at a higher taxonomic level: Penguins (family) vs. Birds (Class) Seals (family) vs. Mammals (Class) Ichneumonidae (family) vs. Insects (Class) Threvidae (family) vs. Insects (Class)  Explanation Over Latitudinal Gradient of Diversity 1. Historical Perturbations – places that have been disturbed (e.g. by glaciation) may have fewer species because of A. Differential rates of extinction B. Inadequate time for species to recolonize 2. Differential rates of evolution – places with more resources or higher temperature may have faster rates of evolution A. Speciation faster than extinction B. More evolutionary experiments tried, and more niches filled  Explanation Over Latitudinal Gradient of Diversity 3. Climatic Stability – stable climate may promote specialization (and speciation) and reduce extinctions 4. Harshness – harsh conditions may limit species numbers 5. Interspecific interactions – biotic interactions may promote specialization and coexistence and are more intense in the tropics 6. Habitat Heterogeneity – diverse habitat structure may permit finer subdivision of resources and greater specialization 7. Productivity/Energy – greater available energy may allow for greater numbers of species to coexist Latitudinal patterns can be extended to altitude (elevation) and ocean depth Bird Species in Peru and New Guinea BIOGEOGRAPHIC THEORY AND ZONES  BIOGEOGRAPHY geographic patterns of species distribution & the processes that result in such patterns. distribution of life forms, past & present, & the causes of such distributions. describes the distributions of living & fossil species of plants & animals across the Earth's surface as consequences of ecological & evolutionary processes. Some Questions Related to Biogeography Why did some/several organisms become extinct? What factors contribute to the occurrence of unique species in some geographical units? How did speciation and species gradients occur? What environmental factors influence distribution of organisms? Why there are a certain number of species in a particular geographic region? Biogeography is a synthetic science. Geography Evolutionary Biology Soil science Geology Climatology Ecology Evolution Paleontology Molecular Systematics  Some Fundamentals in Biogeography Evolution (change in genetic composition of a population due to adaptation & counteradaptation) Extinction (disappearance of a species) Dispersal (movement of populations away from their point of origin, related to migration) Range and distribution Endemic areas Species variations Based on relatively complete compilations of species within well-studied groups, such as birds and mammals, biogeographers identified six different biogeographic realms or zones within which species tend to be closely related and between which turnovers in major groups of species are observed.  Biogeographic Realms or Zones Realm Continental areas Examples of distinctive included or endemic taxa Palearctic Temperate Eurasia and Hynobiid/Asiatic northern Africa salamanders Oriental Tropical Asia Lower apes(macaque) Ethiopian Sub-Saharan Africa Great apes (Gorilla) Australian Australia, New Guinea, Marsupials and New Zealand Nearctic Temperate North America Pronghorn antelope, ambystomatid/mole salamanders Neotropic Subtropical Central Hummingbirds, America and South antbirds, marmosets America Biogeographic Realms or Zones Major Terrestrial Biomes Biome distribution is closely associated with climate Factors regulating or limiting the distribution of organisms – BARRIERS 1) physical barriers such as land (e.g. islands & mountain and water 2) climatic barriers such T0, moisture, sunlight, etc 3) biologic barriers such as absence of food, presence of competitors, predators, or diseases  The patterns of species distribution level can usually be explained through a combination of historical factors Speciation Extinction Continental drift Glaciation (and associated variations in sea level, river routes, and so on) River or stream capture, in combination with the area and isolation of landmasses (geographic constraints) Available energy supplies Permian-Triassic Period Jurassic Period Cretaceous Period Present Day SE Asia Reconstructions 50-0 Ma © Robert Hall 1995 50 48 46 45 44 43 42 41 40 39 38 37 36 34 33 32 31 30 29 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 1 0  Equilibrium Theory of Island Biogeography (by Robert MacArthur and Edward O. Wilson, 1967) the number of species living on an island is a function of extinction and immigration rates on the island species diversity of an area is the result of an equilibrium between colonization and extinction. the number of species found on an island (the equilibrium number) is determined by two factors, the effect of distance from the mainland & the effect of island size, that would affect the rate of extinction on the islands & the level of immigration. > Implies a constant turnover in species, i.e., continual changes in species composition. Species diversity depends on the balance between immigration rate and the extinction rate of species or populations on these islands  more species can go immigration of extinction extinct because of species new species interactions and limited niches rate equilibrium saturation – new individuals won’t represent new species number of species present The success of dispersal and colonization is directly proportional to the size of the island The probability of species reaching and colonizing an island (or patch) is inversely proportional to the distance between the island (or patch) and the mainland that is the source of immigrants/ colonizers  Factors that Influence Island Communities Degree of isolation (distance to nearest neighbor, and mainland) Length of isolation (time) Size of island (larger area usually facilitates greater diversity) Climate (tropical versus arctic, humid versus arid, etc.) Location relative to ocean currents (influences nutrient, fish, bird, and seed flow patterns) Initial plant and animal composition if previously attached to a larger land mass (e.g., marsupials, primates, etc.) The species composition of earliest arrivals (if always isolated) Serendipity (the impacts of chance arrivals) Human activity Applications/ Implications of Island Biogeography Habitat fragmentation (insularization) – there could be “ecosystem decay” or “faunal collapse” (there is species loss as new equilibrium number is achieved, esp. for larger species); creation of metapopulations Development of habitat corridors as a conservation tool to increase connectivity between habitat islands. Habitat corridors can increase the movement of species between parks and reserves. Green bridges as wildlife corridor Wildlife corridors connecting critical habitats Implications of Island Biogeography Conservation planning gives priority on one large reserve that could hold more species; larger reserves should be the norm in reserve design  Implications of Island Biogeography Conservation planning gives priority on one large reserve that could hold more species; – larger reserves should be the norm in reserve design Speciation – allopatric and sympatric ✓ allopatric – populations of the same species become geographically isolated preventing genetic interchange ✓ sympatric – new species evolve from a single ancestral species while inhabiting the same geographic region Effects of fragmentation 1. Reduction in total area (sampling effect problems) loss of original habitat diversity exclusion of some species by chance reduction in population size of species (small population problems) Species that is adapted well to particular site conditions Species with a large facilitative effect on other members of the community (dominant species) Effects of fragmentation 2. Formation of disjunct areas (insularization effect) decrease in dispersal and immigration Isolation of population faunal collapse or relaxation (habitat patch remain but no more immigration) vulnerability during dispersal to other patches Effects of fragmentation 3. Increase in edge habitat further reduction in effective habitat area (edge habitat is poor) increased predation (associated with edge or adjacent habitat) invasion of exotics (edge habitat is altered enough to allow invasive species to establish themselves) disease (from adjacent areas) Change in microclimate  What species are most affected by fragmentation? 1. Area sensitive (e.g., carnivore with large area, low prey density) 2. Isolation sensitive (e.g., reproductive life history requires a dispersal phase through a certain kind of habitat) 3. Edge sensitive 4. Rare species (because of sampling effect - reduction in total habitat and or reduced population size) 5. Specialists or highly coevolved species (e.g., some species of birds require large tracts of old growth. Must maintain both populations)