Effects of forest fragmentation on the beetle assemblage at the relict forest of Fray Jorge, Chile

Barbosa, Olga; Marquet, Pablo A.

doi:10.1007/s00442-002-0951-3

Cited by 81 publications

(65 citation statements)

References 41 publications

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“…The most common explanation for this trend is that there is a mixing of distinct fragment and matrix faunas at habitat edges, giving rise to a zone of overlap with greater overall species richness (Ingham & Samways, 1996;Magura, 2002). While this is the most general species richness pattern, it is by no means universal, as a number of studies have found either no edge effect for species richness (Davies & Margules, 1998;Mönkkönen & Mutanin, 2003) or a positive correlation (Davies, Melbourne & Margules, 2001 b ;Barbosa & Marquet, 2002;Bieringer & Zulka, 2003). Evidently, in some systems many species avoid edges and the matrix-dwelling fauna is not always speciose enough to compensate for the loss of species at edges (Fig.…”

Section: Edge Effects (1 ) Community Composition At Habitat Bounmentioning

confidence: 99%

Confounding factors in the detection of species responses to habitat fragmentation

2005

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Habitat loss has pervasive and disruptive impacts on biodiversity in habitat remnants. The magnitude of the ecological impacts of habitat loss can be exacerbated by the spatial arrangement -or fragmentation -of remaining habitat. Fragmentation per se is a landscape-level phenomenon in which species that survive in habitat remnants are confronted with a modified environment of reduced area, increased isolation and novel ecological boundaries. The implications of this for individual organisms are many and varied, because species with differing life history strategies are differentially affected by habitat fragmentation. Here, we review the extensive literature on species responses to habitat fragmentation, and detail the numerous ways in which confounding factors have either masked the detection, or prevented the manifestation, of predicted fragmentation effects.Large numbers of empirical studies continue to document changes in species richness with decreasing habitat area, with positive, negative and no relationships regularly reported. The debate surrounding such widely contrasting results is beginning to be resolved by findings that the expected positive species-area relationship can be masked by matrix-derived spatial subsidies of resources to fragment-dwelling species and by the invasion of matrix-dwelling species into habitat edges. Significant advances have been made recently in our understanding of how species interactions are altered at habitat edges as a result of these changes. Interestingly, changes in biotic and abiotic parameters at edges also make ecological processes more variable than in habitat interiors. Individuals are more likely to encounter habitat edges in fragments with convoluted shapes, leading to increased turnover and variability in population size than in fragments that are compact in shape. Habitat isolation in both space and time disrupts species distribution patterns, with consequent effects on metapopulation dynamics and the genetic structure of fragment-dwelling populations. Again, the matrix habitat is a strong determinant of fragmentation effects within remnants because of its role in regulating dispersal and dispersalrelated mortality, the provision of spatial subsidies and the potential mediation of edge-related microclimatic gradients.We show that confounding factors can mask many fragmentation effects. For instance, there are multiple ways in which species traits like trophic level, dispersal ability and degree of habitat specialisation influence specieslevel responses. The temporal scale of investigation may have a strong influence on the results of a study, with short-term crowding effects eventually giving way to long-term extinction debts. Moreover, many fragmentation effects like changes in genetic, morphological or behavioural traits of species require time to appear. By contrast, synergistic interactions of fragmentation with climate change, human-altered disturbance regimes, species interactions and other drivers of population decline may magnify the impacts...

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Section: Edge Effects (1 ) Community Composition At Habitat Bounmentioning

confidence: 99%

Confounding factors in the detection of species responses to habitat fragmentation

2005

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“…In contrast to other studies (Didham et al 1998;Barbosa and Marquet 2001), the highest species richness was encountered in isolated forest fragments and old teak. Moreover, the similarity of arthropod assemblages was high, despite long distances among replicate sites (16-19 km).…”

Section: Edge Effects In Old Teak Plantations and Isolated Forest Fracontrasting

confidence: 99%

Arthropod diversity in Lama forest reserve (South Benin), a mosaic of natural, degraded and plantation forests

Lachat

Attignon

Djego

et al.

Topics in Biodiversity and Conservation

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Abstract. Arthropod assemblages were examined in Lama forest reserve, a protected area situated in the Dahomey gap, southern Benin, composed of plantations, degraded forest and remnants of natural forest. The objectives were to compare assemblages in relation to forest type and use, to elucidate the value of forest plantations for biodiversity conservation and to identify indicator species for specific forest habitats. Arthropods were collected over an 11-month period, using standardized sets of traps (pitfall, emergence, Malaise and flight intercept traps). Nine different habitats were studied, including natural and degraded forest, forest plantations (Tectona grandis and Senna siamea) of different age, and isolated forest fragments. Our analysis focused on detritivorous and xylophagous arthropods but also included ground beetles and heteropterans, totalling 393 species. We found no differences in species richness among natural and degraded forest habitats in the centre of the reserve (Noyau central). Outside of the Noyau central, species richness was highest in old teak plantations and isolated forest fragments and lowest in young teak and fuelwood plantations. Detrended correspondence analysis (DCA) separated three main groups: (1) natural forest, (2) degraded forest and young plantations, and (3) old plantations and isolated forest fragments. Multiple regression of DCA scores of the first two axes on environmental variables identified one natural and three disturbance-related predictors of arthropod assemblages in Lama forest: soil type (texture), canopy height, naturalness (proportion of Guineo-Congolian plant species) and understorey vegetation cover. We identified 15 indicator species for six different forest habitats. The highest numbers were found in abandoned settlements and old teak plantations. b-diversity was similar among the three DCA ordination groups (degraded forest excluded). Values for b-diversity were relatively high, suggesting that all major forest habitats contribute significantly to regional species pools and should therefore be protected. To enhance arthropod diversity, we propose that management practices in Lama forest should aim to encourage the development of species-rich understorey vegetation of the Guineo-Congolian phytogeographical region.

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“…Forest fragmentation leads to the increase of forest edge in relation to forest core and it might have harsh consequences for most animals and plants (Fagan et al, 1999;Laurance and Yensen, 1991), changing their distribution, behaviour, and survival, due to habitat loss (Barbosa and Marquet, 2002;Murcia, 1995;Sartorius et al, 1999;Ishino et al, 2012). Such consequences may be evident up to 500m inside a forest fragment (Laurance, 1991;, but most of these effects are more obvious in the first 35m (Rodrigues, 1998) to 60m (Lovejoy et al, 1986).…”

Section: Introductionmentioning

confidence: 99%

The importance of remnant native vegetation of Amazonian submontane forest for the conservation of lizards

Silva¹,

Santos-Filho²,

Canale

2014

Braz. J. Biol.

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Forest fragmentation affects animal population dynamics mainly by loss of habitat and disruption of animal movement. Lizard assemblages are affected by environmental changes, but, depending on their ecological needs, some species might be more vulnerable than others. The southern Amazon suffers accelerated anthropic actions replacing natural environments by farmland (crops and pasture). This region is considerably drier than most of the northern Amazon, with stational semi-deciduous forests fragmented and isolated by pasture, and crops to a lesser extent. Here we report data on lizard assemblages using semi-deciduous forests, forest edge and the surrounding pasture in the southern Amazon in Mato Grosso, Brazil. Lizards were collected in 21 forest fragments (41 to 7,035 ha) surrounded by pasture; using pitfall traps placed on a degradation gradient -from pasture inwards forest fragment (up to 200 m). We collected 242 individuals (14 species, seven families) in 6,300 trap-days. The pattern of species occurrence was largely nested and this nesting was associated with three habitat guilds (generalist, edge-tolerant, and forest species). Although there was no obvious fragmentation effect on lizards diversity community-wise, Hoplocercus spinosus, Bachia dorbignyi, Micrablepharus maximiliani and Kentropyx calcarta were more vulnerable to such effects than all other ten species collected. We verified that assemblages inhabiting pasture and forest edge are a nested subset of assemblages from the forest core. The remnant native vegetation is not distributed homogeneously and lizards species can persist in different parts of the landscape, therefore we recommend the protection of forest remnants as an important conservation action for lizards of the southern Amazon.Keywords: herpetology, Amazon, community ecology, conservation, nestedness.Efeito de borda sobre a comunidade de lagartos em fragmentos de floresta semidecidual submontana ao sul da Amazônia Resumo A fragmentação de florestas afeta a dinâmica das populações animais por meio, principalmente, da perda de habitat e interrupção dos movimentos dos animais. Assembléias de lagartos são afetados por mudanças ambientais, mas, a depender de suas demandas ecológicas, algumas espécies são mais vulneráveis do que outras. A Amazônia Meridional sofre ações antrópicas aceleradas substituindo ambientes naturais por terras voltadas para agropecuária (cultivos e pasto). Esta região é consideravelmente mais seca do que a maior parte das terras ao norte da Amazônia, com florestas estacionais semi-deciduais fragmentadas e isoladas por pasto, e, em menor extensão, cultivos agrícolas. Neste estudo apresentamos informações sobre uso de bordas e pastagem de lagartos confinados a fragmentos de florestas semi-decíduas no sul da Amazônia em Mato Grosso, Brasil. Foram coletados lagartos em 21 fragmentos florestais (41 a 7,035 ha) cercados por pasto; usando armadilhas de queda (pitfalltraps) colocadas em um gradiente de degradação -do pasto em direção ao interior do fragmento floresta...

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Effects of forest fragmentation on the beetle assemblage at the relict forest of Fray Jorge, Chile

Cited by 81 publications

References 41 publications

Confounding factors in the detection of species responses to habitat fragmentation

Confounding factors in the detection of species responses to habitat fragmentation

Arthropod diversity in Lama forest reserve (South Benin), a mosaic of natural, degraded and plantation forests

The importance of remnant native vegetation of Amazonian submontane forest for the conservation of lizards

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