Springer Old Growth Forests - Chapter 19 pot

Impacts of Land Use on Habitat Functionsof Old-Growth Forests and their Biodiversity Dorothea Frank, Manfred Finckh, and Christian Wirth 19.1 Introduction While this book has a clear foc

Impacts of Land Use on Habitat Functions

of Old-Growth Forests and their Biodiversity

Dorothea Frank, Manfred Finckh, and Christian Wirth

19.1 Introduction

While this book has a clear focus on the biogeochemical function of old-growthforest, the pivotal role of old-growth forests in the conservation of biodiversity hasbeen a recurring theme in several chapters [e.g Chap 15 (Schulze et al.); Sect 16.3

in Chap 16 by Armesto et al.; Sect 17.1 in Chap 17 by Grace and Meir; Sect 13.5

in Chap 13 by Bergeron et al.; and Sect 20.3.2 in Chap 20 by Freibauer, thisvolume] It is because of their function of habitat provision that non-governmentalorganisations all over the world thrive to conserve old-growth forests1 Thisincludes a plethora of activities ranging from raising public awareness of the threat

to endangered species, to the promotion of environmental research and education,

to concrete actions such land acquisition and anti-deforestation campaigns

It is beyond the scope of this chapter to exhaustively review the science ofspecies conservation in old-growth forests Instead, we would like to provide a briefintroduction to this fascinating subject by presenting examples that serve to illus-trate the key habitat functions of old-growth forests in different biomes In addition,

we will discuss historic impacts and actual human threats to old-growth forestsworldwide, and their respective consequences with regard to habitat function

1 ‘‘WWF [‘‘World Wide Fund For Nature’’](http://www.panda.org/index.cfm); Greenpeace International (http://www.greenpeace.org/international/); Taiga Rescue Network (http://www.taigarescue.org/en// index.php; Finnish Nature League (http://www.luontoliitto.fi/metsa/forest/background/); Nature Con servancy (http://www.nature.org/); Friends of the Earth International (http://www.foei.org/); Ancient Forest International (http://www.ancientforests.org/); Ancient Forest Exploration and Research (http:// www.ancientforest.org/afer.html); Primal Nature (http://www.primalnature.org); Australian Wilderness Society (http://www.wilderness.org.au/); etc.

C Wirth et al (eds.), Old ‐Growth Forests, Ecological Studies 207, 429 DOI: 10.1007/978 ‐3‐540‐92706‐8 19, # Springer‐Verlag Berlin Heidelberg 2009

19.2 Old-Growth Forests – Habitat Function

The internal environmental conditions of old-growth forests differ from those ofearlier successional stages in two ways On the one hand, the fine-scale heterogene-ity of environmental conditions and structural elements tends to be higher in old-growth forests On the other hand, the resulting mosaic of patches is stable over longtime-scales The habitat function of old-growth forests, and their propensity to hostdiverse animal and plant assemblies, is closely related to this special mix of spatialheterogeneity and temporal stability The higher spatial variability and associatedstructural diversity is believed to provide a wider array of niches The process thatcreates the spatial variability in old-growth forests is the mortality of single trees orgroups of trees, often as a consequence of small-scale disturbances In other words,the notion of habitat- and thus species-rich old-growth forest is fully compatiblewith the intermediate disturbance hypothesis of diversity (Connel 1978) In addi-tion, temporal stability could promote speciation (Fjeldsa˚ and Lovett 1997) and thusthe evolution of mutualistic interactions On the flipside of this, specialised old-growth species are vulnerable to drastic regime-shifts and often disappear whenstands are destroyed by disturbances or heavily altered by management

It follows that plant and animal communities in old-growth forests are unique andoften different from other types of forests, as the following examples show: winter birdpopulations in different forest types in west central Pennsylvania in the UnitedStates, showed significantly higher species richness and abundances in old-growthstands compared to other forest types (Haney 1994) Ernst et al (2007) could showthat amphibian communities of primary tropical forests were generally diverse andtheir composition unpredictable In contrast, communities of logged or secondaryforests were less diverse and more predictable due to strong environmental filtersthat reduced the number of species intolerant of strong fluctuations in microclimate.Similar results were found in a study on hawk moth assemblages in Southeast-Asia,with the relative frequency of subfamilies of Sphingidae changing significantlyfrom primary to disturbed forests (Beck et al 2006), and in species changes inMalayan arboreal ant communities due to anthropic forest degradation (Floren andLinsenmair 2005; Floren et al 2001) These shifts in species composition indicateenvironmental constraints acting on the community

If gradients of ‘old-growthness’ can induce changes in diversity and tion, we may also expect to see differences in individual performance Lomolinoand Perault (2007) analysed the body size of selected mice or shrew species infragmented and extensive stands of old-growth temperate rainforests in the north-western United States Individuals from three species (Peromyscus keeni, Sorexmonticolus, Sorex trowbridgii) were significantly smaller in small forest fragmentsthan in more extensive stands of old-growth forest The comparison between largeold-growth stands and small fragments surrounded by monospecific plantations orearly-successional stands points to the importance of stand extent for the fitness ofindividuals and populations Woltmann (2002) analysed bird community responses

composi-to human disturbance in lowland Bolivia and found several species, e.g the ringed

antpipit (Corythopis torquata) and the spot-backed antbird (Hylophylax naevia),that avoid exploited forests.

In the following sections we will discuss how different environmental istics of old-growth forests are related to their function as a habitat for flora and fauna

character-19.2.1 Structure

The special structural features of old-growth forests (see Chap 2 by Wirth et al., andTable 13.2 in Chap 13 by Bergeron et al., this volume; Mosseler et al 2003), such asmultiple tree strata, uneven-aged or multi-aged structure, the presence of old indivi-duals of late-successional species, canopy gaps and dead and dying trees in varyingstages of decay (Mosseler et al 2003), especially large-sized coarse woody detritus(Bobiec et al 2005), provide niches and fulfil the structural and trophichabitat requirements of old-growth dependent wildlife In this context, structure is aproxy for a complex mixture of nutritional and behavioural requirements

Old-growth forests in humid climates normally host partly heterotrophic phyte communities, formed depending on the geographical region by fungi,bryophytes and lichens, ferns,Orchidaceae, Bromeliaceae and many other vascularplant taxa As a general feature, epiphyte diversity and biomass increases with standage Lichen and bryophyte diversity depends on microsite heterogeneity, and barkroughness; stem structure and chemical surface properties become more diversewith tree diameter and age (Friedel et al 2006; Belincho´n et al 2007) Vascularepiphytes generally depend on detritus accumulation on the trunk and branches,and on structural requisites such as broken branches and half fallen trees, whichdevelop as stands age The epiphyte communities themselves contribute to thestructural diversity and provide habitat for a specialised fauna including arboricou-lous amphibians, reptiles and mammals as well as stem-gleaning birds and a stillinsufficiently known number of invertebrates

epi-Many large woodpeckers occur only in late-successional or old-growth forests.Examples are the pileated woodpecker (Dryocopus pileatus) in North-Americanforests, the Magellanic woodpecker (Campephilus magellanicus) from temperatePatagonian Nothofagus forests, or the recently rediscovered ivory-billed wood-pecker (Campephilus principalis) in the southeastern United States and Cuba(Hartwig et al 2004; Fitzpatrick et al 2005; Hill et al 2006; Vergara and Schlatter2004) They serve as examples of animals that need large decaying and dead trees

as feeding substrates and to carve out cavities for nesting Thereby, they also act askeystone species as their abandoned large holes provide nesting, roosting, hidingand feeding sites for other birds, small mammals, reptiles, amphibians and inverte-brates (Simberloff 1998; McClelland and McClelland 1999; Bonar 2000; Aubryand Raley 2002) The number and size of cavities is significantly related to treediameter (Lindenmayer et al 2000) and thus to tree age Schlatter and Vergara(2005) observed higher abundances of three bird species around sap wells drilled

by the Magellanic woodpecker Other examples of old-growth-associated birds are

the seasonally frugivourous gray-cheeked thrush (Hylocichla minima) and theblackbacked woodpecker (Picoides arcticus), which feed on larvae and insects ondying conifers and occur predominantly in boreal old-growth forests (Thompson

et al 1999; Mosseler et al 2003) The life-history requirements of the northernspotted owl (Strix occidentalis caurina), a federally listed ‘‘threatened’’ species inthe Unites States, are associated with late-successional habitats, due to this species’preference for large caves (Hershey et al 1998; Andrews et al 2005; Forsman et al.2005) and structural understorey requirements for foraging (North et al 1999).Two ground-gleaning tapaculo species of Southern American temperate rain-forests, the black-throated huet-huet (Pteroptochos tarnii) and the ochre-flankedtapaculo (Eugralla paradoxa), are regionally present only if some old-growth forestpatches remain (see Sect 16.3 and Table 16.1 in Chap 16 by Armesto et al., thisvolume) Reid et al (2004) explain this pattern with preferences for food resourcesand escape-cover

19.2.2 Stand Microclimate

In all biomes, old-growth forests tend to have a structurally complex and dynamicvertical and horizontal light environment, with understorey light generally below 5%near the forest floor in closed forest and few microsites with high light levels (Chap 6

by Messier et al., this volume) Although being variable at a micro-scale, relativemicroclimatic stability is a constant feature of old-growth habitats at the macro-scale In other words, old-growth forests possess a high density and continuity ofmicro-sites that are buffered against variations in temperature, light and humidity.Thus it is not surprising that a high number of stenoecous species evolved in old-growth forests Many species closely bound to old-growth forests are poorlyadapted to microclimatic changes (Laurance et al 2006b) They lack resistancemechanisms against frost or desiccation, or depend on species that lack theseproperties, such as plethodontid salamanders (e.g the North American genusAneides; Spickler et al 2006; Mahoney 2001), Chilean leptodactylid frogs (Correa

et al 2006) or desiccation-sensitive vascular plants (e.g ChileanValdivia gayana),Hymenophyllaceae (Dubuisson et al 2003) and bryophytes (Friedel et al 2006).These taxa typically depend on the usually moist and well-buffered microclimaticconditions typical of old-growth forests (Wilson 2003), and are often inserted incomplex food webs or embedded in mutualistic interactions in terms of seed dispersal

or pollination

19.2.3 Spatiotemporal Stability

Until the beginning of the Neolithic period, old-growth forests prevailed in manyparts of the humid ecosystems of the tropical, temperate and boreal zone (Asouti

and Hather 2001; Kalis et al 2003; Marinova and Thiebault 2008) Extended forests

in earlier successional stages predominated mainly in areas subject to intensiveregimes of natural disturbances, such as wind, volcanic disturbances or natural fires.Long-term spatiotemporal stability of forest ecosystems at meso- and macro-scale seems to be an important precondition for the occurrence of many obligateold-growth species Hinojosa et al (2006) analysed the relationships betweenearly Miocene palaeofloras and the actual vegetation in the Chilean CoastalCordillera in south-central Chile They concluded that the notable evolutionarystability of many ancient lineages in the analysed vegetation in terms of morpho-logical persistance and floristic similarity is due to the extremely conservativeenvironment of the coastal forests Smith-Ramirez (2004) describes the forests

of the Chilean coastal range as a centre of endemism and explains this withpleistocenic forest continuity in coastal refugia and post-pleistocenic stability ofthe respective forest ecosystems Meijaard et al (2008) found a positive correlationbetween phylogenetic age and susceptibility to timber harvest in Borneanmammals Lineages that evolve in forest ecosystems that are stable on an evolu-tionary time scale apparently lack, in many cases, the plasticity to adapt to openconditions

Complex functional plant animal interactions have evolved in many ancientforest ecosystems In tropical forests and to a lesser extent also in temperateand boreal forests, animals have crucial functions as pollinators (e.g insects,birds, bats) and/or dispersal agents of plants (e.g birds, mammals) They defendother species against herbivory or predation (e.g ants) and they facilitate andaccelerate nutrient recycling (e.g termites, beetles) Fungi are key organisms forlignin decomposition and plant fungi associations are mutualistic key strategiesused to deal with nutrient poor sites (e.g.Orchidaceae) or with humid and coolenvironments (e.g Ericaceae), to mention just a few selected groups of forest-relevant mutualisms

Old-growth species often differ from early-successional species in their tional traits Several studies (Hamann and Curio 1999; Kitamura et al 2005;Tabarelli and Peres 2002) report higher percentages of zoochorous trees withlarger fruits and specialised frugivore seed dispersers in old-growth compared toearly-successional forests from central Philippines, north-eastern Thailand andsouth-east Brazil, respectively Many large frugivore species are restricted tointact old-growth habitats, and early-successional stages or secondary forests donot fulfil their ecological requirements To analyse old-growth specific habitatfunctions, species quality in terms of specific functional traits and ecologicalservices matters

func-The classical intermediate disturbance hypothesis predicts maximum speciesrichness of ecosystems under intermediate disturbance intensity and is generallyvalid in forest ecosystems at the landscape level (e.g Molino and Sabatier 2001).However, the increase in overall species richness under intermediate disturbance isthe result of a gain in disturbance-adapted generalists and occurs at the expense ofmore specialised old-growth species intolerant of disturbances (Roxsburgh et al.2004; Kondoh 2001)

19.3 Characteristic Human Impacts on Old-Growth Forests

in Different Biomes and their Impact on Habitat

Characteristics, Habitat Functions and Biodiversity

Neither the process nor the structural definitions of old-growth forest necessarilypreclude human impact However, the allowable degree of human impact is subject

to debate Armesto et al (Chap 16, Sect 16.1) consider old-growth condition tohave ‘‘ a species composition that has not been significantly modified (byrecurrent human impact or other large disturbance at least during the past twocenturies) Mosseler et al 2003 require‘‘minimal evidence of human disturbance’’

as an old-growth attribute Many authors emphasise that anthropogenic bances of forests are common if not ubiquitous (Redford 1992; Chap 17 byGrace and Meir, this volume)

distur-Severe man-made disturbances in old-growth forests have persistent effects onspecies composition and are, in many cases, not completely reversible This is especiallytrue under ongoing human impacts2 Recolonisation of habitat is an extremely slowprocess for species that depend on stable environmental conditions, have limited(diaspore) mobility or are embedded in trophic or functional mutualisms

Several authors describe the floristic legacy of ancient woodland fragments i.e.woodland defined by the historic continuity of its forest cover in temperate zones

of Europe and the eastern United States, characterised by plant species that do noteasily recolonise reestablished forests after agricultural land use (Bellemare et al.2002; Hermy et al 1999; Graae et al 2004; He´rault and Honnay 2005) Traitscorrelated with historic continuity of forest fragments include, for example, bar-ochory and myrmecochory, i.e generally short-distance dispersal strategies andlow diaspore production

In most forest types, it takes several centuries of a low disturbance regime todevelop old-growth conditions (see Sect 2.4 in Chap 2 by Wirth et al., this volume)and little is known about disturbance thresholds that impede or allow old-growthforests to develop The spatial extent and the intensity of anthropogenic impacts onold-growth forests differ according to economic driving forces, and the type ofimpacts and factors For example, impacts can be confined to property lines ornatural boundaries, or can trespass in a diffuse manner into old-growth forests Thefollowing section summarises typical human impacts on forest ecosystems withindifferent biomes, and the consequences these human impacts have for the habitatfunction of old-growth forests Table 19.1 shows the impacts caused by diversesocioeconomic driving forces on the habitat function of old-growth forests indifferent biomes

2 Lawrence (2004) observed a reduction in tree species diversity in repeated cycles of shifting cultivation in west Kalimantan, partially due to long distance dispersal limitations and changes in soil nutrients.

19.3.1 Boreal Forests

The climatic and edaphic conditions of the boreal forest region had largely impededagricultural land use until modern times The local populations in Eurosiberian andNorth-American boreal forests have been predominantly hunters and/or transhu-mant reindeer nomads, with low population densities and thus little impact on forestcover (Wallenius et al 2005) Thus, the boreal forests remained relatively intactuntil the beginning of industrialised forest exploitation; 300-year-old forests repre-sent the natural state ofPicea-dominated landscapes in north-eastern Fennoscandiaand north-western Russia (Wallenius et al 2005) Since human activities began inboreal areas, they have become the main agent of fire ignition (Wallenius et al

Table 19.1 Impacts of various anthropogenic drivers on the habitat function of old growth (OG) forest ecosystems in different biomes The grey scale indicates the importance of the impact (dark grey low, mid grey medium, light grey high) The figures indicate specific types of impacts and processes on habitat functions

Driver Spatial effect Impact a

Biome: Confined/diffuse Boreal Temperate Tropical Governmental interior colonisation

Collection of fruits, ornamental

and medical plants

Urbanisation Confined 1,2,3,4,6 2,5,6 Fragmentation by roads and

2005; Mollicone et al 2006), and fires have become more frequent (Mollicone et al.2006) Illegal logging increases in boreal regions, particularly in the Russian FarEast and the Baltic region (Taiga Rescue Network 2004).

Given that large stand-replacing fires are part of the natural dynamics of borealforests (see Gromtsev 2002), the questions of how to evaluate the higher man-madefire frequency and whether clear-cut logging effectively mimics the effects of firesare pivotal for evaluating their impact on boreal old-growth forests

Stand-replacing forest fires and clear-cut logging both eliminate canopy trees,but there are important differences, especially with respect to spatial patterns,temporal regularity and the amount of legacy deadwood: natural fires are alwayspatchy, leaving parts of the landscape to escape fire for long periods (Chap 13 byBergeron et al., this volume; Gossow 1996), and opening the possibility of thedevelopment of old-growth islands or corridors Large fires (2 20
103ha) leaveislands with a median size of about 10 ha (Eberhart and Woodard 1987) and thusfulfil the forest cover requirement for moose (Euler 1981, in Eberhart and Woodard1987) In Eurasian boreal forests characterised by non-stand-replacing recurringsurface fires (Wirth 2005), the effect of fire is to create a stable, fine-grainedage-class mosaic with high structural b-diversity (Sannikov and Goldammer1996) On the contrary, large-scale clear cuts (clear cuts up to more than10,000 ha in size have been reported4) are very uniform and rarely exhibit remnantpatches of the original vegetation Remnant patches favour wildlife in several ways:first, they serve as stepping stones and seeds for recolonisation of the area; second,they create habitat ‘edges’ required by some species, and third, they function asrefugia

In contrast to the short and regular cycles of clear-cuts, the frequency of naturalfires is highly irregular and unpredictable; they often spare wet microsites alongriver flood plains, swamps, lakes or river channels (Furayev 1996), and formirregular boundaries at the landscape-scale Fire and timber harvest remove livewood but, although being highly variable, fire removes far less live wood thanintensive timber harvest and, with the exception of extremely severe fires, it isunlikely that much of the large diameter live wood burns (Chap 8 by Harmon, thisvolume)

In boreal forests, vascular plant diversity decreases from early-successional tolate-successional forests, but cover and diversity of bryophytes increases in old-growth boreal forests (Sect 6.4.2 in Chap 6 by Messier, this volume; Hollings-worth et al 2006) As dispersal distances for many bryophytes are less than 50 m,they need a local source of propagules and sufficient time to develop rich commu-nities These communities are thus threatened by large-scale clear-cuts and shortrotations (Newmaster et al 2003) Many cyanolichen taxa are associated withstands having sufficient ‘old-growth characteristics’ with regard to canopy micro-climate and throughflow, which cannot develop in even-aged hemlock stands with a

4 See Greenpeace Canada ‘‘Threats to the Boreal Forest’’ (http://www.greenpeace.org/canada/en/ campaigns/boreal/threats to the boreal forest)

rotation of 120 years (Radies and Coxson 2004) Newmaster et al (2003) reachedsimilar conclusions for cedar-hemlock forests of British Columbia, where onlyold-growth forests provide a microclimate to form a rich community of raredessication-sensitive liverworts.

A broad variety of forest-dwelling animals also depend on old-growth teristics The endangered woodland caribou (Rangifer tarandus caribou) is asso-ciated with late-successional or old-growth forests where arboreal hair lichens, theirmain winter food source, are abundant (Apps et al 2001; Mosnier et al 2003).Another of the many other examples is the endangered saproxylic beetle speciesPytho kolwensis, which is restricted to virgin spruce-mire forests with a standcontinuity of at least 170 years as it requires long-term continuous availability ofsuitable host trees (Siitonen and Saaristo 2000)

charac-To summarise, the present industrialised exploitation of boreal forests, with itslarge-scale clear cuts often followed by monospecific reforestation5with a short andpredictable rotation, does not mimic natural disturbance dynamics It alters theboreal ecosystems substantially, and the proportion of old-growth boreal forestsharbouring sensitive species decreases

19.3.2 Temperate Forests

The land-use history of temperate forests differs greatly from that of the borealregions Since the beginning of the younger Neolithic, temperate forests have beencleared for agricultural land use or affected by fire wood and charcoal productionand grazing (Asouti and Hather 2001; Kalis et al 2003; Marinova and Thiebault2008) Agrotechnical innovation led to human population increases and subsequentexpansion of agricultural land This gradual conversion of forests and the manifoldsmall-scale exploitation of the remaining fragments produced diverse landscapepatterns in the different temperate regions of the world, reflecting the socioeco-nomic conditions and the pace of the conversion processes

In the following, we will discuss the driving forces of forest conversion, theresulting forest systems, and the consequences for old-growth biota, focussing onEurope and Chile as examples

19.3.2.1 Europe

Almost no primary forests are left in Central Europe Pollen records indicate thatfloristic changes had begun already in the middle Neolithic (Kalis et al 2003).Forest degradation and clearing producing marked signals in pollen composition

5 Plantation forests often exclude pioneer shrubs, non timber tree species and, especially, older age classes are very scare or non existent, thus food supply and cover availability for wildlife species are reduced (Gossow 1996)

started in the younger Neolithic period at about 6300 BP Forest destruction started

in regions with favourable soils and climate, and later extended into areas withminor productivity Pollen composition further suggests a simultaneous increase

of wood gathering, charcoal production and animal husbandry, causing largeareas of secondary forests, dominated by early-successional tree species (Kalis

et al 2003)

With the population increase in the Middle Ages, extended old-growth forestsremained only in the upper montane and subalpine belt and in royal huntingreserves Most other forests, many of them used as commons, were heavily impact-

ed by livestock husbandry, firewood and timber extraction, tannery (e.g oakcoppice) or charcoal production, and litter removal Forest overexploitation andthe removal of litter and topsoil caused soil degradation and the formation ofextended heathlands on sandy soils Mining regions and salterns in the Austrianalps had their own forest regulations and authorities to satisfy their specificdemands for pine and spruce

Systematic large-scale reforestation started early in the nineteenth century tofulfil the growing urban and industrial demand for timber Species compositionand structure of planted forests was different from natural forests, due to coevalstands, short rotation periods without large old trees and extensive utilisation

of Norway spruce and scots pine outside their natural habitat The latest importantprocess that has impacted the Central European forests is the atmospheric nitrogendeposition that grew dramatically throughout the twentieth century, and reached apeak in the 1980s6

Currently, about 30% of central Europe is covered by forest (Gu¨thler 2003), butunmanaged old-growth forests exist on less than 0.2% of the area, mostly in themountains Thus, there is little possibility to deduce the general features of primaryold-growth forests in lowland areas from analyses of these fragments

Nonetheless, we find a high diversity of management schemes, due partly to thehistoric legacy of a fine-textured land tenureship The historic diversity of privateand public stakeholders, each with their own interests in terms of productivity,investment return and weighting of contrasting environmental versus economicfactors, generated a multitude of forest types7 Although this created forest land-scapes characterised by a high g (inter-stand) diversity, the mean size of the forestparcels is small This combination has important consequences for biota requiringold-growth habitats Due to the lack of extensive forest, the fauna of large woodland

6 Actually, air borne nitrogen deposits in German forests fluctuate from 20 to 40 kg ha1a1, with important regional differences (Gu¨thler et al 2005) Wright et al 2001 report a trend of slightly reduced atmospheric nitrogen deposition in Central Europe compared to the peak in the 1980s.

7 Management schemes range from traditional concepts such as ‘‘coppice’’ for energy demand or

‘‘coppice with standards’’ for energy and construction over ‘‘shelterwood cutting’’ (‘‘Schirms chlag’’, ‘‘Femelschlag’’) to ‘‘selection forestry’’ (‘‘Plenterwald’’) for high quality timber Manage ment philosophies are quite diverse, from clear cut or age class forestry with low b diversity to

‘‘permanent forest’’ (‘‘Dauerwald’’) concepts, and from plantation forestry with alien species to

‘‘close to nature’’ silviculture with site adapted native species.

mammals is extremely impoverished The largest herbivores, such as the Aueroxand the Tarpan, have been extinguished; European bison or moose and top pre-dators such as the brown bear and wolf have been mostly driven back to lesspopulated areas in Northern and Eastern Europe.

Where we find remnants of ancient woodland, they still differ from agricultural secondary forests in terms of their floristic composition Hermy et al.(1999) listed 132 plant species of deciduous forests of Central Europe significantlyrelated with historic woodlands, and found long persistence of these plants evenwithin very small forest fragments Especially taxa with long-lived individuals,poor seed dispersers (gravity or ant dispersal) and short-statured geophytes arerestricted to ancient woodlands (Graae et al 2004; Hermy et al 1999; Herault andHonnay 2005) These findings are not restricted to the temperate forests of Europe,

post-‘‘ herbaceous understorey communities in the mixed-mesophyteic forests of theAppalachians appear unlikely to recover within the present planned logging cycles

of 40 150 years, suggesting continuing loss of diversity of understorey herbaceousplants.’’ (Meier et al 1996)

If we compare mature managed forests with natural old-growth in Germany,managed forests are dominated by few tree species with economic importance(Pinus silvestris, Picea abies, Fagus sylvatica, Quercus robur and Quercus pet-raea) Senescent and damaged trees are rare and typical old-growth features such

as detritus, caves, snags and logs are largely missing This structural depletion has

a heavy impact on parts of the forest biota: 25% of dead-wood dependent fungi in Bavaria are classified as threatened; of the 1,200 wood-dependent(xylobiont) coleopterae in Germany, about 50% are classified as endangered(Gu¨thler 2005) Many insects depend on very specific structural requisites, interms of dead wood diameter, dead wood insolation, and tree species, that arerarely realised in managed forests (Bobiec 2005; Ranius et al 2005; Buse et al.2008; Gu¨thler 2005)

macro-19.3.2.2 Chile

The region where temperate forest ecosystems occur in southern Chile has beenpopulated by humans since at least 12,000 BP (Heusser et al 1996) In the sixteenthcentury, the Spanish conquistadores reported a patchy mosaic of fields and clear-ances in a matrix of extended closed forests south of the Rio Bı´o-Bı´o (approx

37300S) (Berninger 1929) By the mid-nineteenth century, in the course of the so

called ‘‘pacification’’ and organised agricultural colonisation of South CentralChile, the indigenous population was settled in ‘‘reductions’’, and the majority ofthe land was given to European and Chilean settlers investors Since then, thepreviously continuous temperate forest ecosystems of southern-central Chile havesuffered substitution and fragmentation by extensive burning and logging foragricultural and forest land-uses (Berninger 1929; Lauer 1961)

Native forest fragments remained embedded in the subsistence agriculture system

of indigenous Mapuche communities as well as in the more intensive land-use system